QAF011a
Rev. 07 May 26, 07
Haward Technology Middle East
API 653: TANK INSPECTION CODE: Inspection, Repair, Alteration, & Reconstruction of Steel Aboveground Storage Tanks Used in the Petrochemical Industry (API Exam Preparation Training)
January 13-17, 2008 Abu Dhabi, UAE Course Instructor Mr. Ron VanArsdale This document is the property of the course instructor and/or Haward Technology Middle East. No part of this publication may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise, without the prior written permission of Haward Technology Middle East. P.O.Box: 26070, Abu Dhabi, UAE
Tel: +971-2-4488301
Fax: +971-2-4488302
Email:
[email protected]
http://www.haward.org
To the Participant The Course Notes are intended as an aid in following lectures and for review in conjunction with your own notes; however they are not intended to be a complete textbook. If you spot any inaccuracy, kindly report it by completing this form and dispatching it to the following address, so that we can take the necessary action to rectify the matter.
Haward Technology Middle East P.O. Box 26070 Abu Dhabi, UAE Tel.:+971 2 4488301 Fax: +971 2 4488302 Email:
[email protected]
Name Address
E-mail Course Title Course Date Course Location Description of Inaccuracy
Disclaimer
The information contained in these course notes has been compiled from various sources and is believed to be reliable and to represent the best current knowledge and opinion relative to the subject. Haward Technology offers no warranty, guarantee or representation as to its absolute correctness or sufficiency. Haward Technology has no responsibility in connection therewith; nor should it be assumed that all acceptable safety and regulatory measures are contained herein, or that other or additional information may be required under particular or exceptional circumstances.
Haward Technology Middle East COURSE OVERVIEW RE320
API 653: TANK INSPECTION CODE: Inspection, Repair, Alteration, & Reconstruction of Steel Aboveground Storage Tanks Used in the Petrochemical Industry (API Exam Preparation Training) Course Title API 653: TANK INSPECTION CODE: Inspection, Repair, Alteration, & Reconstruction of Steel Aboveground Storage Tanks Used in the Petrochemical Industry (API Exam Preparation Training)
Course Date / Venue Course : January 13-17, 2008 Course Venue: Vincennes Meeting Room, Le Meridien Hotel, Abu Dhabi, UAE Exam : March 19, 2008 Exam Venue : Al Majlis Ballroom Crowne Plaza Hotel, Abu Dhabi, UAE
Course Reference RE320 Course Duration/Credits Five days (40 hours as per API regulations)/4.0 CEUs Course Objectives In order to meet the needs of today's fast changing inspection industry, Haward Technology (ITAC) has developed the "Tank Inspection Course with API 653 Exam Prep.”. The course textbook includes notes and summaries on the tank inspection standards referenced in the API 653 Body of Knowledge. This comprehensive 40 hour course consists of five 8-hour teaching days. It is designed to accomplish a two-fold training agenda: (1) To train those individuals who are interested in obtaining the API 653 Tank Inspection Certification. (2) Train those who require a working knowledge of the intricacies encountered in the working environment. Additionally, quizzes are given at the end of each section; homework is handed out at the end of each class day, which consists of 25 questions per day and is reviewed at the beginning of the following day, and a “practice” exam is administered at the end of the course. Haward Technology is proud of the 90%+ pass rate attained by its students who have sat for the API 653 certification exam.
Training Methodology This interactive training course includes the following training methodologies as a percentage of total tuition hours:50% 30% 20%
Lectures Workshops, Group Work & Practical Exercises Videos & Software RE320 - Page 1 of 8 .
RE320-01-08 |Rev.29|22 December 2007
Haward Technology Middle East Who Should Attend The course is intended for Inspection Engineers who are seeking API-653 certification. Other engineers, managers or technical staffs who are dealing with Steel Aboveground Storage Tanks used in the Petrochemical Industry will also benefit. Course Certificate Haward Technology certificate will be issued to all attendees completing minimum of 75% of the total tuition hours of the course. Course Accreditation Haward Technology’s courses/workshops/seminars meet the professional certification and continuing education requirements for participants seeking Continuing Education Units (CEUs) in accordance with the rules & regulations of the International Association for Continuing Education & Training (IACET). IACET is an international authority that evaluates programs according to strict, research-based criteria and guidelines. The CEU is an internationally accepted uniform unit of measurement in qualified courses of continuing education. Haward Technology Middle East will award 4.0 CEUs (Continuing Education Units) for participants who completed the total tuition hours of this program. One CEU is equivalent to ten Professional Development Hours (PDHs) or ten contact hours of the participation in and completion of Haward Technology programs. A permanent record of a participant’s involvement and awarding of CEU will be maintained by Haward Technology. Haward Technology will provide a copy of the participant’s CEU Transcript of Records upon request. Required Codes and Standards: Listed below are the effective editions of the publications required for the March 19, 2008 API 653, Aboveground Storage Tank Inspector Examination. API Recommended Practice 571, Damage Mechanisms Affecting Fixed Equipment in the Refining Industry, First Edition, December 2003. IHS Product code API CERT 653_571 (includes only the portions specified below) ATTENTION: Only the following mechanisms to be included: 4.2.7 - Brittle Fracture 4.2.16 – Mechanical Fatigue 4.3.2 – Atmospheric Corrosion 4.3.3 – Corrosion under insulation (CUI) 4.3.8 – Microbiologically Induced Corrosion (MIC) 4.3.9 – Soil Corrosion 4.3.10 – Caustic Corrosion 4.5.1 – Chloride Stress Corrosion Cracking (C1-SCC) 4.5.3 – Caustic Stress Corrosion Cracking (Caustic Embrittlement) 5.1.1.11 – Sulfuric Acid Corrosion
API Recommended Practice 575, Inspection of Atmospheric and Low-Pressure Storage Tanks, Second Edition, May, 2005. IHS Product Code API CERT 575 RE320 - Page 2 of 8 .
RE320-01-08 |Rev.29|22 December 2007
Haward Technology Middle East
API Recommended Practice 577, Welding Inspection and Metallurgy, First Edition, October 2004. IHS Product Code API CERT 577 API Standard 650, Welded Steel Tanks for Oil Storage, Tenth Edition, November 1998, including Addendum 1 (March 2000), Addendum 2 (Nov. 2001), and Addendum 3 (Sept. 2003) and Addendum 4 (December 2005). IHS Product Code API CERT 650 API Recommended Practice 651, Cathodic Protection of Aboveground Petroleum Storage Tanks, Third Edition, January 2007. IHS Product Code API CERT 651 API Recommended Practice 652, Lining of Aboveground Petroleum Storage Tank Bottoms, Third Edition, October 2005. IHS Product Code API CERT 652 API Standard 653, Tank Inspection, Repair, Alteration, and Reconstruction, Third Edition, December 2001; including Addendum 1(September 2003) and Addendum 2 (November 2005). IHS Product Code API CERT 653 American Society of Mechanical Engineers (ASME), Boiler and Pressure Vessel Code, 2004 edition with the 2005 Addenda and 2006 addenda. i. ASME Section V, Nondestructive Examination, Articles 1, 2, 6, 7 and 23 (Section SE-797 only). ii. Section IX, Welding and Brazing Qualifications(Section QW only)
IHS Product Code for the ASME package API CERT 653 ASME. Package includes only the above excerpts necessary for the exam. API and ASME publications may be ordered through IHS Documents at 303-3977956 or 800-854-7179. Product codes are listed above. Orders may also be faxed to 303-397-2740. More information is available at http://www.ihs.com. API members are eligible for a 30% discount on all API documents; other exam candidates are eligible for a 20% discount on all API documents. When calling to order please identify yourself as an exam candidate and/or API member. Prices quoted will reflect the applicable discounts. No discounts will be made for ASME documents. Note: API and ASME publications are copyrighted material. Photocopies of API and ASME publications are not permitted. CD-ROM versions of the API documents are issued quarterly by Information Handling Services and are allowed. Be sure to check your CD-ROM against the editions noted on this sheet.
Course Fee US $3,750 per Delegate. This rate includes Participant’s Pack (Folder, Manual, Hand-outs, etc.), buffet lunch, coffee/tea on arrival, morning & afternoon of each day.
Accommodation Accommodation is not included in the course fees. However, any accommodation required can be arranged by Haward Technology at the time of booking.
RE320 - Page 3 of 8 . RE320-01-08 |Rev.29|22 December 2007
Haward Technology Middle East Course Instructor Mr. Ron VanArsdale, PE, USA, is the founder of Inspection Training and Consulting Company (ITAC). His duties include conducting training courses for Haward Technology and ITAC, creating new courses for inspection and other related activities, creating course material, as well as developing custom training programs, customized written practices and providing trouble-shooting consulting services. In the past, Mr. VanArsdale was employed by SGS Industrial Services as the Training Director and the American Welding Society (AWS) as the Curricula and Course Development Manager. In this position he developed various training courses dealing with the AWS Certified Welding Inspector program. He planned, organized, and developed all phases of educational activities for AWS. In addition to these functions, he is a member of the API 653 Questions Committee which devised the API 653 Tank Inspector Certification Examination; as well as a member of the API 570 Questions Committee which is charged with developing the API 570 Piping Inspector Certification Examination. Ron attended San Jacinto College and Texas A&M University, and has a Lifetime Teaching Certificate from the State of Texas. He is an AWS Certified Welding Inspector (CWI), ITAC Level III, an API Certified Aboveground Storage Tank Inspector, and API Certified Piping Inspector, an AWS Certified Welding Educator (CWE) and is an internationally recognized Presenter/Instructor. Additionally, he received the AWS Distinguished Member Award in March, 1989, the AWS CWI of the Year District Award in January, 1993, as well as the AWS District 18 Meritorious Award in September, 1993. He has thirty-three years experience in the erection, maintenance and inspection of buildings, petrochemical facilities, vessels, above-ground storage tanks, piping systems, in addition to teaching welding/inspection education courses. Mr. VanArsdale is professionally affiliated with the American Welding Society, American Society for Nondestructive Testing, American Petroleum Institute, Vocational Industrial Clubs of America, Haward Technology, American Inspection Society, the National Job Core and has been appointed a Kentucky Colonel by the Governor of Kentucky in recognition of his lifetime contribution to his fellow man.
Course Program The following program is planned for this course. However, the course instructor(s) may modify this program before or during the course for technical reasons with no prior notice to participants. Nevertheless, the course objectives will always be met: Day 1: Sunday, 13th of January 2008 0730 – 0800 Registration & Coffee 0800 – 0815 Welcome 0815 – 0900 Introduction 0900 – 0930 Students Take Initial Math Quiz 0930 – 1000 Review Math Quiz Answers 1000 – 1015 Break 1015 – 1045 Overview of Course Outline 1045 – 1230 Review of API 653 Body of Knowledge 1230 – 1330 Lunch RE320 - Page 4 of 8 . RE320-01-08 |Rev.29|22 December 2007
Haward Technology Middle East 1330 – 1445
API 653 - Section 1 – Scope: Introduction, Compliance With This Standard, Jurisdiction, Safe Working Practices
API 653 - Section 2 – Referenced Publications API 653 - Section 3 – Definitions 1445 – 1500 1500 – 1620
1620 – 1720 1720 – 1730 1730
Day 2: 0730 – 0830 0830 – 1000
Break
API 653 - Section 4 - Suitability For Service: General, Tank Roof Evaluation, Tank Shell Evaluation, Tank Bottom Evaluation, Tank Foundation Evaluation API 653 - Section 5 - Brittle Fracture Considerations: General, Basic Considerations, Assessment Procedure Distribute Homework End of Day One
Monday, 14th of January 2008 Review Homework Answers
API 653 - Section 6 - Inspection General, Inspection Frequency Considerations, Inspections from the Outside of the Tank, Internal Inspection, Alternative to Internal Inspection to Determine Bottom Thickness, Preparatory Work for Internal Inspection, Inspection Checklists, Records, Reports, Non-Destructive Testing
API 653 - Section 7 - Materials General, New Materials, Original Materials for Reconstructed Tanks, Welding Consumables
API 653 - Section 8 - Design Considerations for Reconstructed Tanks 1000 – 1015 1015 – 1230
General, New Weld Joints, Existing Weld Joints, Shell Design, Shell Penetrations, Wind Girders and Shell Stability, Roofs, Seismic Design Break
API 653 - Section 9 - Tank Repair And Alteration General, Removal and Replacement of Shell Plate Material, Shell Repairs Using Lap-Welded Patch Plates, Repair of Defects in Shell Plate Material, Alteration of Tank Shells to Change Shell Height, Repair of Defective Welds, Repair of Shell Penetrations, Addition or Replacement of Shell Penetrations, Alteration of Existing Shell Penetrations, Repair of Tank Bottoms, Repair of Fixed Roofs, Floating Roofs, Repair or Replacement of Floating Room Perimeter Seals, Hot Taps
API 653 - Section 10 - Dismantling And Reconstruction General, Cleaning and Gas Freeing, Dismantling Methods, Reconstructions, Dimensional Tolerances
API 653 - Section 11 - Welding Welding Qualifications, Identification and Records
API 653 - Section 12 - Examination And Testing Nondestructive Examination, Radiographs, Hydrostatic Testing, Leak Tests, Measured Settlement During Hydrostatic Testing
API 653 - Section 13 - Marking And Recordkeeping Nameplates, Recordkeeping, Certification
API 653 – Appendices A – G 1230 – 1330 1330 – 1400
Lunch Administer API 653 Section Quiz RE320 - Page 5 of 8 .
RE320-01-08 |Rev.29|22 December 2007
Haward Technology Middle East 1400 – 1500
API 650 - Section 1 - Scope General, Limitations, Compliance, Referenced Publications
API 650 - Section 2 - Materials 1500 – 1515 1515 – 1735
General, Plates, Welding Electrodes Break
API 650 - Section 3 - Design Joints, Bottom Plates, Annular Bottom Plates, Shell Design, Shell Openings, Shell Attachments and Tank Appurtenances, Roofs, Wind Load on Tanks (Overturning Stability)
API 650 - Section 4 - Fabrication API 650 - Section 5 - Erection 1735 – 1745 1745 Day 3: 0730 – 0800 0800 – 0945
General, Details of Welding, Inspection, Testing and Repairs, Repairs to Welds, Dimensional Tolerances Distribute Homework End of Day Two Tuesday, 15th of January 2008 Review Homework Answers
API 650 - Section 6 - Methods Of Inspecting Joints Radiographic Method, Magnetic Particle Examination, Ultrasonic Examination, Liquid Penetrant Examination, Visual Examination API 650 -
Section 7 - Welding Procedure & Welder Qualifications Definitions, Qualification of Welders
API 650 - Section 8 - Marking 0945 – 1000 1000 – 1130 1130 – 1200 1200 – 1230 1230 – 1330 1330 – 1445
Nameplates, Division of Responsibility, Certification Break
API 650 - Appendices B - S Administer API 650 Section Quiz
Slide Show – “Don’t Let This Happen To Your Tank” Lunch
Complete Slide Show -“Don’t Let This Happen To Your Tank” API RP 575 - Section 1 – Scope API RP 575 - Section 3 - Selected Nondestructive Examination (NDE) Methods Ultrasonic-Thickness Measurement, Magnetic Floor Testing
API RP 575 - Section 4 - Types Of Storage Tanks 1445 – 1500 1500 – 1730
General, Storage Tanks with Linings and/or Cathodic Protection, Storage Tanks with Leak Detection Systems, Low-Pressure Storage Tanks Break
API RP 575 - Section 5 - Reasons For Inspection and Causes of Deterioration Reasons for Inspection, Corrosion of Steel Tanks
API RP 575 - Section 6 - Frequency Of Inspection API RP 575 - Section 7 - Methods Of Inspection And Inspection Scheduling External Inspection of In-Service Tanks, Foundation Inspection, Anchor Bolt inspection, Grounding Connection Inspection, Thickness Measurements, Caustic Cracking, Tank Bottoms, Inspection Scheduling, Inspection Checklists
API RP 651 - Section 1 – Scope RE320 - Page 6 of 8 . RE320-01-08 |Rev.29|22 December 2007
Haward Technology Middle East API RP 651 - Section 3 – Definitions API RP 651 - Section 4 - Corrosion of Aboveground Steel Storage Tanks Introduction, Corrosion Mechanisms
API RP 651 - Section 5 - Determination of Need for Cathodic Protection API RP 651 - Section 6 - Methods of Cathodic Protection for Corrosion Control Introduction, Galvanic Systems, Impressed Current Systems, Cathodic Protection Rectifiers
API RP 651 - Section 7 - Design Of Cathodic Protection Systems Barriers to Cathodic Protection, Tank Bottom Replacement, Impervious Membrane Lining, Effects of Impermeable Membrane Secondary Containment Systems
API RP 651 - Section 8 - Criteria For Cathodic Protection API RP 651 - Section 9 - Installation Of Cathodic Protection Systems Introduction, Galvanic Anode Systems, Impressed Current Systems
API RP 651 - Section 10 - Interference Currents API RP 651 - Section 11 - Operation and Maintenance of Cathodic Protection Systems API RP 652 - Section 1 – Introduction API RP 652 - Section 3 – Definitions API RP 652 - Section 4 - Corrosion Mechanisms Chemical Corrosion, Concentration Cell Corrosion, Corrosion Caused by Sulfate-Reducing Bacteria, Erosion-Corrosion in Water Treatment
API RP 652 - Section 5 - Determination of The Need for Tank Bottom Lining General, Design Considerations and Tank Internals, Tank Environmental Considerations, Flexibility for Service Change
History,
API RP 652 - Section 6 - Tank Bottomlining Selection General, Thin-Film Tank Bottom Linings, Thick-Film Tank Bottom Linings
API RP 652 - Section 7 - Surface Preparation General, Precleaning
API RP 652 - Section 9 – Inspection API RP 652 - Section 10 - Repair Of Tank Bottom Linings General, Types of Repairs
API RP 652 - Section 11 - Safety Tank Entry, Manufacturer's Material Safety Data Sheets
API RP 571 - Section 1 – Scope API RP 571 - Section 4 – General Damage Mechanisms Brittle Fracture, Mechanical Fatigue, Atmospheric Corrosion, Corrosion Under Insulation (CUI), Microbiological Induced Corrosion (MIC), Soil Corrosion, Caustic Corrosion, Chloride Stress Corrosion Cracking (Cl SCC), Caustic Stress Corrosion Cracking (Caustic Embrittlement)
API RP 571 - Section 5 – Refining Industry Damage Mechanisms 1730 – 1735 1735
Distribute Homework End of Day Three RE320 - Page 7 of 8 .
RE320-01-08 |Rev.29|22 December 2007
Haward Technology Middle East Day 4: Wednesday, 16th of January 2008 0730 – 0800 Review Homework Answers 0800 – 1000 API RP 577 - Section 1 - Scope
API RP 577 - Section 3 - Definitions API RP 577 - Section 4 – Welding Inspection Tasks Prior To, During and Upon Completion of Welding Operations; Nonconformances and Defects; NDE Examiner Certification; Safety Precautions
API RP 577 - Section 5 – Welding Processes Shielded Metal Arc Welding (SMAW), Gas Tungsten Arc Welding (GTAW), Gas Metal Arc Welding (GMAW), Flux Cored Arc Welding (FCAW), Submerged Arc Welding (SAW), Stud Arc Welding (SW) 1000 – 1015 1015 – 1230
Break
API RP 577 - Section 11 – Refinery and Petrochemical Plant Welding Issues API RP 577 – Appendix A – Terminology and Symbols Weld Joint Types, Weld Symbols, Weld Joint Nomenclature, Electrode Identification
ASME Section V - Nondestructive Test Methods 1230 – 1330 1330 – 1530 1530 – 1545 1545 – 1715 1715 – 1720 1720 Day 5: 0730 – 0800 0800 – 1000 1000 – 1015 1015 – 1230 1230 – 1330 1330 – 1530 1530 – 1545 1545 – 1600 1600
Ultrasonic Thickness Testing, Liquid Penetrant Testing, Magnetic Particle Testing, Radiographic Film Interpretation Lunch
ASME Section IX - WPS and PQR Requirements Review Procedure Exercise Break
ASME Section IX - Welder Certification Distribute Homework End of Day Four Thursday, 17th of January 2008 Review Homework Answers
Question and Answer Session Break
API 653 Sample Exam Lunch
Continue API 653 Sample Exam Review API 653 Exam Answers Break Presentation of Certificates End of Course
Course Coordinator Samah Al Yazouri, Tel: +971-2-44 88 301, Fax: +971-2-44 88 302, Email:
[email protected]
RE320 - Page 8 of 8 . RE320-01-08 |Rev.29|22 December 2007
Table of Contents Section 1
653 Summary 2007
Section 2
650 Sum 2007
Section 3
575 Summary–07
Section 4
RP 651 Summary-07
Section 5
652 Summary-07
Section 6
RP 571 Summary 06
Section 7
577 Summary 06
Section 8
NDE Sum-2007
Section 9
ASME IX Summary-07
Section 10
Welding Metallurgy-97
Section 11
Tech Report Writing-97
Section 1 653 Summary 2007
API - 653 TANK INSPECTION, REPAIR ALTERATION AND RECONSTRUCTION THIRD EDITION - DECEMBER 2001 ADDENDUM 1 - SEPTEMBER 2003 ADDENDUM 2 - NOVEMBER 2005 SECTION 1 - INTRODUCTION 1.1
General 1.1.1
This standard covers carbon and low alloy steel tanks built to API-650 and 12C standards. These standard provide minimum requirements for maintaining the integrity of welded or riveted, non-refrigerated, atmospheric pressure, above ground storage tanks after they have been placed in service.
1.1.2 Scope coverage Foundation, bottom, shell, structure, roof, attached appurtenances and nozzles to the face of the first flange, first threaded joint or first welded end connection. NOTES:
1. 2.
Many API-650 requirements apply that will satisfy this new code. In case of conflict (for in-service tanks) between API12C; 650; and 653, this Code governs.
ITAC API 653 Summary, 2007
Page 1- 1
1.1.6 1.2
API 653 now recognizes API RP 579, Recommended Practice for Fitnessfor-Service. Under API 653 , the owner may use fitness-for-service criteria.
Compliance The owner/operator has ultimate responsibility for complying with API 653 provisions.
1.3
Jurisdiction Statutory Regulation (i.e., local, state or federal) shall govern, unless the requirements of this standard are more stringent than Statutory Regulation.
1.4
Safe Working Practices Safety procedures according to guidelines given in API publications 2015, 2016, and 2217A are suggested for potential hazards involved when conducting internal inspections, making repairs or dismantling tanks. NOTE:
Procedures must comply with any state or federal safety regulation involving "confined space" entry.
ITAC API 653 Summary, 2007
Page 1- 2
SECTION 3 - DEFINITIONS d. An independent organization or individual under contract to and under the direction of an owner or operator and recognized or otherwise not prohibited by the jurisdiction in which the aboveground storage tank is operated. The owner or operator’s inspection program shall provide the controls necessary for use by Authorized Inspectors contracted to inspect above ground storage tanks.
3.1 alteration: Any work on a tank involving cutting, burning, welding or heating operation that changes the physical dimensions and/or configuration of a tank. Typical examples of alterations include: a. The addition of manways and nozzles greater than 12-inch (NPS). b. An increase or decrease in tank shell height. 3.2
definition deleted
3.3
definition deleted
3.4 authorized inspection agency: One of the following organizations that employ an Aboveground Storage Tank Inspector certified by API. a. The inspection organization of the jurisdiction in which the aboveground storage tank is operated. b. The inspection organization of an insurance company which is licensed or registered to and does write aboveground storage tank insurance. c. An owner or operator of one or more aboveground storage tank(s) who maintains an inspection organization for activities relating only to its equipment, and not for aboveground storage tanks intended for sale or resale.
3.5 authorized inspector: An employee of an authorized inspection agency and is certified as an Aboveground Storage Tank Inspector per Appendix D of this standard. 3.6 breakover point: The area on a tank bottom where settlement begins. 3.7 change in service: A change from previous operating condition involving different properties of the stored product such as specific gravity or corrositivity and/or different service conditions of temperature and/or pressure. 3.8 corrosion rate The total metal loss divided by the period of time over which the metal loss occurred. 3.9 critical zone: The portion of the bottom or annular plate within 3 inches of the inside edge of the shell, measured radially inward. 3.10 hot tap: Identifies a procedure for installing a nozzle in the shell of a tank that is in service.
ITAC API 653 Summary, 2007
Page 1- 3
3.11 inspector: A representative of an organization’s mechanical integrity department who is responsible for various quality control, and assurance functions, such as welding, contract execution, etc. 3.12 owner/operator: The legal entity having both control of and/or responsibility for the operation and maintenance of an existing storage tank. 3.13 reconstruction: Any work necessary to reassemble a tank that has been dismantled and relocated to a new site. 3.14 reconstruction organization: The organization having assigned responsibility by the owner/operator to design and/or reconstruct a tank. 3.15 repair: Work necessary to maintain or restore a tank to a condition suitable for safe operation. Repairs include both major repairs (see 3.21) or repairs that are not major repairs. Examples of repairs include: a. Removal and replacement of material (such as roof, shell, or bottom material, including weld metal) to maintain tank integrity. b. Re-leveling and/or jacking of a tank shell, bottom. or roof. c. Adding or replacing reinforcing plates (or portions thereof) to existing shell penetrations. d. Repair of flaws, such as tears or gouges, by grinding and/or gouging followed by welding. 3.16 repair organization: An organization that meets any of the following:
or alters its own equipment in accordance with this standard. b. A contractor whose qualifications are acceptable to the owner/operator of aboveground storage tanks and who makes repairs or alterations in accordance with this standard. c. One who is authorized by, acceptable to, or otherwise not prohibited by the jurisdiction, and who makes repairs in accordance with this standard. 3.17 storage tank engineer: One or more persons or organizations acceptable to the owner/operator who are knowledgeable and experienced in the engineering disciplines associated with evaluating mechanical and material characteristics that affect the integrity and reliability of aboveground storage tanks. The storage tank engineer, by consulting with appropriate specialists, should be regarded as a composite of all entities needed to properly assess the technical requirements. 3.18 external inspection: A formal visual inspection, as supervised by an authorized inspector, to assess all aspects of the tank as possible without suspending operations or requiring tank shutdown (see 6.4.1). 3.19 internal inspection: A formal, complete inspection, as supervised by an authorized inspector of all accessible internal tank surfaces (see6.4.1). 3.20 fitness for service assessment: A methodology whereby flaws contained within a structure are assessed in order to determine the adequacy of the flawed structure for continued service without imminent failure.
a. An owner/operator of aboveground storage tanks who repairs ITAC API 653 Summary, 2007
Page 1- 4
3.21 as-built standard: The standard (such as API standard or UL5 standard) used for the construction of the tank component in question. If this standard is not known, the as-built standard is the standard that was in effect at the date of the installation of the component. If the date of the installation of the component is unknown, then the current applicable standard shall be considered to be the as-built standard. See Appendix A for a list of API welded storage tank standards. The standard used for repairs or alterations made after original construction is the as-built standard only for those repairs or alterations, so there may be more than one as-built standard for a tank. 3.22 current applicable standard: The current edition of the standard (such as API standard or UL standard) that applies if the tank were built today. 3.23 major alteration or major repair: An alteration or repair that includes any of the following: a. Installing a shell penetration larger than NPS 12 beneath the design liquid level.
f. Installing a new bottom. This does not include new bottoms in tanks where the foundation under the new bottom is not disturbed and either of the following conditions is met: 1. For tanks with annular rings, the annular ring remains intact; or, 2. For tanks without annular rings, the alteration does not include welding on the existing bottom within the critical zone. See 3.9 for a definition of the critical zone. Note: The work described in 12.3.2.5 is not considered to be the installation of a new bottom. g. Removing and replacing part of the weld attaching the shell to the bottom, or to the annular plate ring, in excess of the amounts listed in 12.3.2.4. la. h. Jacking a tank shell.
b. Installing a bottom penetration within 12 in. of the shell.
3.24 recognized toughness: A condition that exists when the material of a component is deemed acceptable for use by the provisions of any of the following sections of this standard:
c. Removing and replacing or adding a shell plate beneath the design liquid level.
a. Section 5.3.2 (based on edition of standard of tank's original construction, or by coupon testing).
d. Removing or replacing annular plate ring material where the longest dimension of the replacement plate exceeds 12 in.
b. Section 5.3.5 (based on thickness).
e. Complete or partial (more than one-half of the weld thickness) removal and replacement of more than 12 in. of vertical weld joining shell plates or radial weld joining the annular plate ring.
c. Section 5.3.6 (based on lowest design metal temperature). d. Section 5.3.8 (based on exemption curves).
ITAC API 653 Summary, 2007
Page 1- 5
3.25 unknown toughness: A condition that exists when it cannot be demonstrated that the material of a component satisfies the definition of recognized toughness.
ITAC API 653 Summary, 2007
Page 1- 6
SECTION 4 - SUITABILITY FOR SERVICE 4.1
General 4.1.1
When inspection indicates a change from original physical condition, evaluate to determine suitability for continued service.
4.1.2
This section covers: a. b.
4.1.3
Factors for consideration: (plus engineering analysis and judgment) a. b. c. d. e. f. g. h. i. j.
4.2
Evaluation for continued service. Decisions relative to repairs, alterations, dismantling, relocating, or reconstruction.
Internal corrosion (products or water bottom). External corrosion (environmental exposure). Allowable stress levels. Stored product properties (i.e., Specific Gravity, temperature, corrositivity). Metal design temperatures (at service location). External roof live load, wind and seismic loading. Foundation, soil and settlement conditions. Chemical analysis/mechanical properties (construction. material). Existing tank distortions. Operating conditions (i.e., filling/emptying rates and frequency).
Tank Roof Evaluation (General) 4.2.1.2 4.2.2
Roof plates corroded to an average "t" of less than 0.09" (in any 100 sq. in) Repair or Replace.
Fixed Roofs Determine condition of roof support system (i.e., rafters, girders, columns, bases and out of plumb columns). Corrosion and/or damaged members - Evaluate for repair or renewal. NOTE:
4.2.3
Pipe columns require special attention. Severe internal corrosion may not be evidenced by external visual inspection.
Floating Roofs 4.2.3.1
Cracks/punctures - Repair or replace.
4.2.3.2
Pitting/corrosion - Evaluate for potential penetration before the next scheduled internal inspection.
4.2.3.3
Roof support system, perimeter seals, drain system, venting, other appurtenances. Evaluate. ITAC API 653 Summary, 2007
Page 1- 7
4.2.3.4
See API-650 (Appendix C and H) for evaluation guidance. NOTE:
4.2.4
4.3
Upgrading - Not mandatory to meet those guidelines on floating roofs.
Change of Service 4.2.4.1
Internal pressure: Refer to API-650 (Appendix F) when evaluating/modifying roof or roof-to-shell junction.
4.2.4.2
External pressure: Roof support structure and roof-to-shell junction. Evaluate for effect of design partial vacuum. Refer to API-620.
4.2.4.3
All requirements of API-650 (Appendix M) shall apply before a change of service to operation at temperature above 200°F is considered.
4.2.4.4
See the current applicable standard if operation is to be at lower temperature than original design.
4.2.4.5
Evaluate if change of service will effect normal or emergency venting.
Tank Shell Evaluation 4.3.1.1
Flaws, deterioration, (greater than CA) must be evaluated for continued use suitability.
4.3.1.2
The shell condition, analysis and evaluation shall take into consideration the anticipated loading conditions and combinations including: a. b. c. d. e.
Pressure due to fluid static head. Internal and external pressure. Wind and seismic loads. Roof live loads. Nozzle, settlement and attachment loads.
4.3.1.3
Shell corrosion occurs in many forms and varying degrees of severity resulting in a generally uniform loss of metal over a large surface area or in localized areas. Pitting may also occur, but does not normally represent a significant threat to overall structural integrity unless present in a severe form with pits in close proximity to one another.
4.3.1.4
Methods for determining the minimum shell "t" suitable for continued operation are given in 4.3.2, 4.3.3, and 4.3.4. (see page 1-11 below for minimum shell “t” formula.) ITAC API 653 Summary, 2007
Page 1- 8
4.3.1.5
If the "t" requirements cannot be satisfied, the corroded or damaged areas shall be: a. b. c.
Repaired, or Allowable liquid level reduced, or Tank retired.
NOTE: 4.3.2
The maximum design liquid level shall not be exceeded.
Actual Thickness Determination: a. b.
See Inspection of Corrosion Areas (Fig. 4-1, Page 4-2). The controlling thickness in each shell course, where corroded areas of considerable size occur, must be determined.
NOTE:
This section deals with the averaging of corroded areas. This is not an exact science and should be used only when an area is questionable for repair. For exam purposes, you will be supplied with 't2 " and the diameter of the tank.
EXAMPLE: A tank 38 feet tall, 150 feet diameter, displays a large area of corrosion. The corroded area measures approximately 23 inches wide and 21 inches in height. The inspector has determined the least thickness in the area of corrosion to be 3/16 or .187 inches. Calculate the "L" length. ANSWER:
L = 3.7 Dt2 L = 3.7 (150 X .187) L = 3.7 28.05 L = 3.7 X 5.30 L = 19.61 inches or 19 5/8 inches approx.
4.3.2.2
Widely scattered pits may be ignored if: a.
b.
No pit results in the remaining shell "t" being less than one-half (1/2) of the minimum acceptable tank shell "t" (exclusive of the CA); And The sum (total) of their dimensions along any vertical line does not exceed two inches (2") in an eight inch (8") length. (See Fig. 4-2).
ITAC API 653 Summary, 2007
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EXAMPLE: Three (3) pits in close proximity. Dimension (measure) vertically - each pit. Add the sum (total dimensions) together. * d1 + d2 + d3 --- 2" NOTE:
If the pit dimension totals (measured vertically) exceed 2" in an 8" length, then these pits must be considered as strength factors.
4.3.3 Minimum Thickness Calculation for Welded Tank Shell This method is similar to the “one foot” method, as used in API Std 650. Note the stress tables and joint efficiencies are critical to this calculation. Emphasis should be placed on this section when studying for the API 653 Certification Exam. API has not established rules for “rounding off”.
ITAC API 653 Summary, 2007
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Minimum Thickness Calculation for Welded Tank Shell (API 653 Section 4.3.3.1) tmin = 2.6 (H-1)DG SE tmin = the minimum acceptable thickness, in inches, for each course as calculated from the above formula; however, tmin shall not be less than 0.1 inch for any tank course. D=
nominal diameter of tank, in feet.
H = height from the bottom of the shell course under consideration to the maximum liquid level when evaluating an entire shell course, in ft; or = height, from the bottom of the length L (see 4.3.2.1) from the lowest point of the bottom of L of the locally thinned area to the maximum liquid level, in ft; or =
height from the lowest point within any location of interest to the maximum liquid level, in ft.
G=
Highest specific gravity of the contents.
S=
Maximum allowable stress in pounds per square inch; use the smaller of 0.80Y or 0.429T for bottom and second course; use the smaller of 0.88Y or 0.472T for all other courses. Allowable shell stresses are shown in Table 4-1 for materials listed in the current and previous editions of API Std. 12C and Std. 650. Note: For reconstructed tanks, S shall be per the current applicable standard.
Y=
Specified minimum yield strength of the plate; use 30,000 psi if not known.
T=
The smaller of the specified minimum tensile strength of the plate or 80,000 psi; use 55,000 psi if not known.
E=
Original joint efficiency for the tank. Use Table 4-2 if original E is unknown. E=1.0 when evaluating the retirement thickness in a corroded plate, when away from welds or joints by at least the greater of one inch or twice the plate thickness.
ITAC API 653 Summary, 2007
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FOR UNKNOWN MATERIAL Maximum Allowable Stress (in PSI)
NOTE:
Use the smaller of:
First or Second Course
Other Courses
(Yield) .80Y = .80 X 30,000 = 24,000 or (Tensile) .429T = .429 X 55,000 = 23,595
(Yield) .88Y = .88 X 30,000 = 26,400 or (Tensile) .472T = .472 X 55,000 = 25,960
The Third Edition of API 653 has added Table 4-1, Maximum Allowable Shell Stresses (not for use for reconstructed tanks). This will make stress calculations much easier.
Sample problem for minimum thickness of a welded tank shell. An inspection of a welded, 138 foot diameter tank, 50 feet tall, 48 feet fill height shows some scattered pitting in the first course. What is the minimum shell thickness required for this tank, if the specific gravity of the product is 0.9?
tmin = ? D = 138' H = 48' G = .9 S = 23,600 (from Table 4-1) E=1
tmin = 2.6 (H-1) DG SE
tmin = 2.6 (48-1)((138)(.9) 23,600(1) 15,177.24 23,600 tmin = .643"
ITAC API 653 Summary, 2007
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Practice Problem tmin = 2.6 (H-1) DG SE A 190' diameter tank has a pit that measures 5/16" deep in the first course, what is the min t, if the fill is 42 feet and the specific gravity is 0.6? (The pit is not in a weld seam or HAZ.) The material is unknown. S=
Table 4-1
E=
Original joint efficiency for the tank. Use Table 4-2 if original E is unknown. E = 1.0 when evaluating the retirement thickness in a corroded plate, when away from welds or joints by at least the greater of one inch or twice the plate thickness.
Explanation of Practice Problem tmin = 2.6 (H-1) DG SE
tmin = ?
D = 190 S = 23,600
H = 42 E=1
G = .6
tmin = 2.6 (42-1) (190) (.6) 23,600(1) tmin = 12,152.4 23,600 tmin = .515 inches
ITAC API 653 Summary, 2007
Page 1- 13
Maximum Allowable Fill Height Calculation (4.3.3.2) H= Ht =
StEtx t min 2.6D
+1
Height from the bottom of the shell course under consideration to the hydrostatic test height when evaluating an entire shell course in ft; or
=
Height from the bottom of the length, L, (see 4.3.2.1) for the most severely thinned area in each shell course to the hydrostatic test height in ft; or
=
Height from the lowest point within any other location of interest to the hydrostatic test height in ft.
St =
Maximum allowable hydrostatic test stress in lbf~in.2 ; use the smaller of 0.88Y or 0.472T for bottom and second courses; use the smaller of 0.9Y or 0.519T for all other courses.
Notes: 1. Depending on the specific gravity of the content used to determine tmin, Ht may be less than H. Testing the tank to H may yield the corroded area. 2. If Ht is less than H, owner/operator shall determine the consequence and acceptability of operating the tank to H, its maximum design liquid level. Repairs to shell sections above H, shall comply with the requirements of 12.3.2. 3. For reconstructed tanks, St shall be per the current applicable standard.
ITAC API 653 Summary, 2007
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Sample problem for maximum allowable fill height of a welded tank shell. Ht = StEtmin 2.6D What is the hydrostatic test height of a welded tank 112’ diameter, that has a minimum thickness of .115 inches in the first course? (Shell material unknown) (E=1). Ht = StEtmin 2.6D
+1
Ht = 26,000 (1) .115 2.6(112) Ht = 2,990 291.2
+1
+1
Ht = 11.26’ Ht = 11’ 3 1/8”
The 3rd Edition of API 653 takes a two step approach for hydrostatic testing height H, Ht. STEP A: Controlling Thickness Ht = StEtmin 2.6D + 1 STEP B: Locally Thinned Areas Ht = StEtmin 2.6D
ITAC API 653 Summary, 2007
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4.3.4
Minimum "t" calculation for Riveted Tank Shell 4.3.4.1
Use the same formula as 4.3.3.1, except that the following allowable stress criteria and joint efficiency shall be used: a. b.
S = 21,000 lbs./sq./in. E - 1.0 for shell plate 6" or more away from rivets.
NOTE: 4.3.4.3
See Table 4-3 for joint efficiencies for locations within 6" of rivets.
Evaluate to what extent, if any, riveted joints have been affected by corrosion. Relate "bulging" condition between internal butt-straps and shell plates with stress placed on rivets.
INTERNAL CORROSION - OBSERVATIONS/COMMENTS Based on experience and personal observations only, the following is presented for field data survey and evaluation. A.
Tank Bottoms 1.
2. 3.
B.
For tanks with potential sour water present, check closely for accelerated corrosive attack around outer periphery. This is usually found at the lowest point and at the water collection point. Also applies to lower 4" - 6" of internal shell. Some product services specifically attack weld seams and the adjacent HAZ Not Internal, but related, corrosion often occurs to the underside of tank bottoms. If bottom leak is suspected as a result of underside corrosion, be prepared for a slow, long duration, expensive operation to verify and/or locate problem areas. * Later reference under Bottom Evaluation.
Tank Shells 1. 2. 3. 4. 5.
See prior comment on lower shell area with potential for sour water attack. * Sour Crude tanks very susceptible to this type corrosion. The theory that the hot side (i.e., west side thermal input) is more corrosive has not been justified or verified. Preferential attack on weld seams, HAZ, scaffold lug removal areas, etc., is not uncommon. Extreme upper, non-wetted shell area often experiences accelerated corrosion. This is a very real possibility in sour crude or No. 6 fuel oils due to high sulfur content in the vapor phase. Watch for accelerated metal loss (usually smooth, perhaps even grooved) at the normal product high liquid level in weak acid service.
ITAC API 653 Summary, 2007
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C.
Tank Roofs/Support Structure Should corrosion be found in the upper shell, the potential for a like loss should be suspected on the internal roof plates, the rafter/structural members and the roof support columns. These specific areas are exposed to the same environment as the upper, non-wetted shell surface. If only the two (2) lower shell rings show accelerated corrosion, closely check the roof support columns. Problems to the same degree and elevation may be present. 4.3.5
Distortions 4.3.5.1
Includes out-of-roundness, buckled areas, flat spots, peaking and banding at welded joints.
4.3.5.2
Potential causes: a. b. c. d. e.
4.3.6
4.3.9
Foundation settlement Over or under-pressuring High winds Poor shell fabrication/erection Repair Techniques
Flaws cracks and laminations a.
Examine/evaluate to determine need, nature or extent of repair. If repair is required, develop procedure (with sketch as necessary). Evaluate all issues on a case-by-case basis.
b.
Cracks in the shell-to-bottom (corner) weld are critical. Removal, not weld-over, is required.
Shell Penetrations Consideration details include: a. b. c. d. e. f.
Type and extent of reinforcement. Weld spacing. Proximity of reinforcement to shell weld seams. Thickness of component parts. Deterioration (internal/external). Existing welds met API 650, 7th Edition or later.
ITAC API 653 Summary, 2007
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4.3.10 Operation at Elevated Temperatures This section requires evaluation of the tank if it operates at temperatures above 200oF, but less than 500oF A special consideration should be given to tanks that are converted to elevated temperatures (4.3.10.2). 4.4
Tank Bottom Evaluation 4.4.1
General All aspects of corrosion phenomena, all potential leak or failure mechanisms must be examined. Assessment period shall be less than or equal to the appropriate internal inspection interval. NOTE:
4.4.2
Excessive foundation settlement can have a serious impact on the integrity of shell and bottoms. Refer to Appendix "B" for tank bottom settlement techniques.
Causes of Bottom Leaks Consider cause/effect/repair: a. b. c. d. e. f. g. h. i. j. k. l.
4.4.6
Internal pitting. Corrosion of weld seams and HAZ Weld joint cracking. Stresses (roof support loads and settlement). Underside corrosion (i.e., normally pitting). Inadequate drainage. Lack of an annular plate ring, when required. Uneven settlement (with resultant high stress). Roof support columns (or other supports) welded to bottom without allowance for adequate movement. Rock or gravel foundation pads. Non-homogeneous fill under bottom (i.e., shell, rock, clay, wood stakes, etc.). Inadequately supported sumps.
Bottom Measurements Methods (Appendix G may apply) a. b. c. d. e. f.
Spot U. T. measurement. Visual, internal survey with hammer test. UT "B" scan. MFE or MFLT Section removal (i.e., coupon). Abrasive blast (scan for capillary wicking).
ITAC API 653 Summary, 2007
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4.4.7
Minimum "t" for Tank Bottom Plate Two (2) Methods: a. b.
4.4.8
4.4.7.3
If the minimum bottom "t", at the end of the in-service period of operation, are calculated to be less than the bottom renewal thickness given in Table 6-1 (page 6-3), the bottom shall be repaired as follows: Lined, repaired, replaced or the interval to the next internal inspection shortened. Unless an RBI program is in place.
4.4.7.4
Critical zone thickness is redefined in this paragraph. Note the plate thickness in the critical zone shall be the smaller of 1/2 the original bottom plate thickness or 50% of tmin of the lower shell course, but not less than 0.1 inch.
4.4.7.7
The bottom extension shall be no less than 0.1 inch thick and must extend beyond the outside toe of the shell-to-bottom weld at least 3/8 inch.
Minimum "t" - Annular Plate Rings 1. 2. 3. 4.
4.5
Deterministic (See 4.4.7.1) - A long, drawn out formula/data process. Not normally used. Probabilistic (See 4.4.7.2) - Normal process. Statistical analysis based on thickness data resulting from visual, mechanical or UT survey.
See Table 4-4 (page 4 - 10). With product SG less than 1.0 that require annular plates for other than seismic loading consideration -- Also see Table 4-4. SG greater than 1.0: Refer to Table 3-1 of the API-650 standard. Add any specified corrosion allowance (4.4.8.2).
Tank Foundation Evaluation 4.5.1
General - (causes of foundation deterioration): a. b. c.
Settlement Erosion Cracking of concrete (i.e., calcining, underground water, frost, alkalies and acids).
ITAC API 653 Summary, 2007
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4.5.1.2
4.5.2 and 4.5.3
Description - concrete deterioration mechanisms. a.
Calcining - (loss of water of hydration). Normally occurs when concrete has been exposed to high temperature for a period of time. During intermediate cooling periods, the concrete absorbs moisture, swells, loses its strength and cracks.
b.
Chemical attack: cyclic changes in temperature and by freezing moisture.
c.
Expansion in porous concrete caused by freezing moisture - Spalling or serious structural cracks.
d.
Concrete bond deterioration - Attack by sulfate-type alkalies or even chlorides.
e.
Temperature cracks (hairline with uniform width). Not Normally serious.* Potential moisture entry points with resulting corrosion of the reinforcing steel.
General a. b. c.
For repair or renewal. Prevent water entry. Distortion of anchor bolts and excessive cracking of the concrete structure in which they are embedded may indicate: (i) (ii)
Serious foundation settlement. Tank over pressure uplift condition.
ITAC API 653 Summary, 2007
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SECTION 5 - BRITTLE FRACTURE CONSIDERATIONS 5.1
General Provides a procedure to assess the risk of failure due to brittle fracture, plus establishes general guidance for avoiding this type failure. Now there is an eleven (11) step assessment procedure.
5.2
Basic Considerations See Fig. 5-1 "Decision Tree" as the assessment procedure to determine failure potential. Prior incident data whereby brittle fracture has occurred either shortly after erection during hydrostatic testing or on the first filling in cold weather, after a change to lower temperature service, or after a repair/alteration. This failure has primarily occurred in welded tanks. 5.2.1 Reported conditions involving failures (primarily involving welded tanks): a. b. c. d.
Hydro test at initial erection. First filling in cold weather. After a change to lower temperature service. After a repair-alteration.
5.2.2 Any change in service must be evaluated to determine if it increases the risk of failure due to brittle fracture. For example, the change to a more severe service involving one of the following: a. b.
5.3
Lower operating temperature (especially below 60°F). Product with a higher specific gravity. * Consider need for hydrostatic test when any repair or alteration does not meet all requirements of the 653 standard or deterioration of the tank has occurred since the original hydrostatic test.
Assessment Procedure 5.3.1 – 5.3.12 Direction for Assessment General Comments: 1.
Fracture assessment would most likely be conducted by a metallurgist or design specialist.
2.
Several options exist based on the most severe combination of temperature and liquid level experienced by the tank during its life, whereby an increased potential for brittle fracture failure exists: a. b. c. d.
Restrict the liquid level. Restrict the minimum metal temperature Change service to a lower Specific Gravity. product. A combination of the three areas listed above. ITAC API 653 Summary, 2007
Page 1- 21
3.
Remember: Reducing the storage temperature increases the potential for failure. Shell stresses are increased and potential for failure is greater with a stored product change to a higher specific gravity.
SECTION 6 - INSPECTION 6.1
General - In-service Inspection of Tanks
6.2
Inspection Frequency Considerations 6.2.1
Some factors determining inspection frequency: a. b. c. d. e. f. g. h. i. j. k. l. m.
6.3
Nature of stored product. Visual inspection/maintenance results. Corrosion rates and/or allowances. Corrosion prevention systems. Previous inspection results. Methods-materials of construction or repair. Tank location (i.e., isolated, grouped, high risk areas). Potential for air, water or soil pollution. Leak detection systems. Change in operating mode. Jurisdictional requirements. Changes in service (including water bottoms). The existence of a double bottom or a release prevention barrier.
6.2.2
The interval between inspections (internal/external) is most influenced by its service history, unless special reasons indicate an earlier inspection is required.
6.2.3
Local jurisdictional regulations (i.e., vapor loss values, seal condition, leakage, proper diking and repair procedures) should be known by inspection personnel in their own locality, or should be furnished by owner-user to inspectors who function at remote locations.
External Inspection (Routine In-Service Type) 6.3.1.1 through 6.3.1.3 Routine external in-service inspection may be done by owner-user operator personnel. Routine requirements include: a. b. c.
Visual inspection from the ground. Intervals shall not exceed one month. External check for leaks, distortion, settlement, corrosion, foundation, paint, insulation, etc. ITAC API 653 Summary, 2007
Page 1- 22
6.3.2
6.3.3
Scheduled Inspections (All tanks) 6.3.2.1
Formal visual external inspection at least every five (5) years or RCA/4N years (where RCA is the difference between the measured shell thickness and the minimum required thickness in mills, and N is the shell corrosion rate in mills per year), whichever is less, by an Authorized Inspector. Tank may be in operation.
6.3.2.2
Remove insulation to extent necessary to determine condition of roof and shell.
6.3.2.3
Tank grounding system components, shunts, cable connection, etc., shall be visually checked.
6.3.2.4
Visually check tank grounding components.
In-service UT "t" measurement of shell. 6.3.3.1
Extent of UT survey - Determined by owner-user.
6.3.3.2
When UT is used as inspection method, intervals shall not exceed the following: a. b. c.
Five (5) years from commissioning new tank. At five year intervals (existing tanks where corrosion rate is not known. When the corrosion rate IS known, the maximum interval shall be the smaller of RCA/2N years (where RCA is the difference between the measured shell thickness and the minimum required thickness in mils, and N is the shell corrosion rate in mils per year) or fifteen (15) years.
6.3.3.3
Internal tank shell inspection (out-of-service condition) can be substituted for a program of external UT measurements made during in-service condition.
6.3.4.1
Cathodic Protection System -- Survey in accordance with API RP 651.
ITAC API 653 Summary, 2007
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6.4
Internal Inspection 6.4.1
General Internal inspection is primarily designed to: a. b.
Determine that bottom is not severely corroded or leaking. Gather data necessary to determine minimum "t" of shell and bottom for proper evaluation. NOTE:
c. 6.4.1.2
6.4.2
Prior in-service UT data may be used as criteria in the assessment process.
Identify/evaluate any tank bottom settlement. New item. The Authorized Inspector who is responsible for evaluation of a tank must visually examine each tank and review the NDE results.
Inspection Intervals 6.4.2.1
Internal inspection intervals are determined by: a. b.
Corrosion rates established during prior surveys. Anticipated corrosion rates based on experience with tanks in similar service.
NOTES:
1. 2. 3.
6.4.2.2
6.4.3
Normally, bottom corrosion rates will control. Set interval so that bottom plate minimum "t"(at the next inspection) are not less than the values listed in Tbl 6-1. In No case, shall the internal inspection interval exceed twenty (20) years.
If corrosion rates are not known and similar service data is not available (to determine bottom plate "t" at next inspection), the actual bottom "t" shall be determined by inspection(s), interval shall not exceed ten (10) years of operation to establish corrosion rates.
Alternative Internal Inspection Interval For unique combinations of service, environment and construction, the owner/operator may establish the interval using an alternative procedure. This method includes: a. b. c. d.
Determining bottom plate "t". Consideration of environmental risk. Consideration of inspection quality. Analysis of corrosion measurements. ITAC API 653 Summary, 2007
Page 1- 24
As an alternative an RBI program may be used. NOTE: Must be documented and made part of permanent record. 6.5
Alternative to Internal Inspection to Determine Bottom "t" In cases where construction, size or other aspects allow external access to bottom, an external inspection (in lieu of internal) is allowed to meet requirements of Table 6-1. Documentation also required.
6.7
Inspection Checklists Appendix "C" provides sample checklists of items for consideration for in or outof-service inspections. A similar checklist also exists in API RP 575. NOTES:
6.8
1. 2. 3. 4.
Would be very expensive and time consuming. Would require support personnel/equipment. Plant personnel could check a number of items. All are not necessary, unless special condition exists.
Records 6.8.1
General a. b.
Records form the basis of any scheduled inspection/maintenance program. If no records exist, judgment may be based on tanks in similar service. Owner/operator must maintain a complete record file on each tank consisting of three (3) types: i. ii. iii.
6.8.2
Construction Records Inspection History Repair/Alteration History
Construction Records May include the following: a. b. c. d. e. f. g.
Nameplate information Drawings Specifications Construction completion report NDE performed Material analysis Hydro data
ITAC API 653 Summary, 2007
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6.8.3
Inspection History a.
b. c. 6.8.4
Includes all measurements taken, condition of all parts inspected and a record of all examination and tests. Include a complete description of any unusual condition with probable reason for problem and recommendation for corrections. Sketches and detailed repair procedure should be provided if so desired by the customer. Corrosion rate and inspection interval calculations should be furnished and made a part of the permanent file.
Repair/Alteration History Includes all data accumulated from initial erection with regard to repairs, alterations, replacements, plus data associated with service changes (i.e., specific gravity and temperature). Include results of coating-lining experience.
6.9
Reports 6.9.1
Recommended repairs shall include: a. b.
6.9.2
General inspection reports shall include: a. b. c. d. e.
6.10
Reason for the repair. Sketches showing location and extent.
Metal thickness measurements Conditions found Repairs Settlement data Recommendations
Non-Destructive Examinations NDE personnel shall meet the qualifications identified in 12.1.1.2, but need not be certified in accordance with Appendix D. However, the results must be reviewed by an Authorized Inspector.
ITAC API 653 Summary, 2007
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SECTION 7 - MATERIALS 7.1
General This section provides general requirements for materials when tanks are repaired, altered or reconstructed. (See Section 9 for specific data).
7.2
New Materials Shall conform to current applicable tank standards.
7.3
Original Materials for Reconstructed Tanks 7.3.1
All shell plates and bottom plates welded to the shell shall be identified. Original contract drawings, API nameplate or other suitable documentation do not require further identification. Materials not identified must be tested.(See 7.3.1.2.). 7.3.1.2
7.3.1.3
7.3.3
If plates are not identified, subject plate to chemical analysis and mechanical tests, as required in ASTM-A6 and A370 (including Charpy V-Notch). API-650 impact values must be satisfied. For known materials, plate properties (at a minimum) must meet chemical and mechanical API-650 requirements with regard to thickness and design metal temperature. Flanges, fasteners, structural, etc., must meet current standards. Welding consumables must conform to the AWS classification that is applicable.
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SECTION 8 - DESIGN CONSIDERATIONS RECONSTRUCTED TANKS 8.2
New Weld Joints a. b.
8.3
Must meet applicable standard. Butt-weld joint with complete fusion and penetration.
Existing Joints Must meet as built standard.
8.4
Shell Design 8.4.1
When checking design criteria, the "t" for each shell course shall be based on measurements taken within 180 days prior to relocation.
8.4.2
Determining maximum design liquid level for product is determined by: a. b. c. d.
8.5
Calculate the maximum liquid level (each course) based on product specific gravity. Actual "t" measured for each course. Material allowable stress for each course. (See Table 3-2 - API-650). Selected design method.
Shell Penetrations 8.5.1
New/replacement penetrations must be designed, detailed, welded and examined to meet current applicable standard.
8.5.2
Existing penetrations must be evaluated for compliance with the as built standard.
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SECTION 9 - TANK REPAIR AND ALTERATION 9.1
General Basis for repair/alteration shall be equivalent to API-650 standard. 9.1.3 All repairs must be authorized by the Authorized Inspector or an engineer. The Authorized Inspector will establish hold points. 9.1.4 All proposed design, welding procedures, testing methods, etc., must be approved by the Authorized Inspector or an engineer. 9.1.5 Appendix F summarizes the requirements by method of examination and provides the acceptance standards, inspector qualifications, and procedure requirements. This is a good summary of NDT requirements and includes procedures from API 650, but it should not be used alone.
9.2
Removal and Replacement - Shell Plate 9.2.1 Thickness of the replacement shell plate shall not be less than the greatest nominal "t" of any plate in the same course adjoining the replacement plate except thickened insert plate. NOTE:
9.2.2
When evaluating plate suitability, any change from the original design condition (i.e., specific gravity, pressure, liquid level and shell height) must be considered.
Minimum Dimensions of Replacement Shell Plate 9.2.2.1
Twelve inches (12"), or 12 times the "t" of the replacement, whichever is greater. NOTE:
9.2.2.2
The replacement plate may be circular, oblong, square with rounded corners or rectangular with rounded corners, except when an entire plate is replaced. (See Fig. 9-1 for details).
When replacing entire shell plates, it is permissible to cut and reweld along the existing horizontal weld joints. Maintain weld spacing as per established API-650 values. NOTE:
Prior to welding the new vertical joints, the existing horizontal weld must be cut for a minimum distance of twelve inches (12") beyond the new vertical joints. As normal, weld verticals before roundseams.
ITAC API 653 Summary, 2007
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9.2.3
Weld Joint Design 9.2.3.1
Replacement Shell Plates - Butt joints with complete penetration and fusion. Fillet welded lapped patch plates are permitted.
9.2.3.2
Weld Joint Design a. b. c.
9.2.3.3
See API-650 (3.1.5.1 through 3.2.5.3). Joints in existing lap-weld shells may be repaired according to as built standard. Weld details - See API-650(5.2) and API-653 (Section 11).
Refer to Figure 9-1 for Minimum weld spacing dimensions. NOTE:
9.3.1
Special requirements for shell plates of unknown toughness, not meeting the exemption curve for brittle fracture: The new vertical weld must be at least 3” or 5T from bottom joints.
Lapped patch shell repairs are now an acceptable form of repair, API 653, Second Edition, Addenda 1. Existing patch plates may be evaluated to this Standard. 9.3.1.2
Lap patches may not be used on plate thicker than 1/2" or to replace door sheets.
9.3.1.3
Lap patch plates are not to be thicker than 1/2” or thinner than 3/16”.
9.3.1.4
All lap patch plates may be circular, oblong, square, rectangular or meet the nozzle reinforcing plate shapes of API 650.
9.3.1.5
Lap patch plates may cross welds. See figure 9-1 for weld spacing details.
9.3.1.6
Lap patch plates may extend to and intersect with the external shell-to-bottom joint. Internal lap patches shall have 6” toe-to-toe weld clearance between the patch and the shell-to-bottom weld.
9.3.1.7
Maximum size of lap patch plates is 48” x 72”, minimum 4”.
9.3.1.8
Shell openings are not allowed within a lapped patch repair.
9.3.1.9
UT required in the areas to be welded, searching for plate defects and remaining thickness. ITAC API 653 Summary, 2007
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9.3.1.10
9.3.2
9.3.3
Lapped patch plates may be used to close holes. 9.3.2.1
The lap patch plate must be seal-welded, including the inner perimeter of the hole. The minimum hole diameter is 2”.
9.3.2.2
Nozzle necks and reinforcing plates shall be entirely removed prior to installation of a repair plate.
9.3.2.3
The overlap of a repair plate shall not exceed 8 times the shell thickness, minimum overlap is 1”. The minimum repair plate dimension shall be 4 inches.
9.3.2.4
The repair plate thickness shall not exceed the nominal thickness of the shell plate adjacent to the repair.
Lapped patch plates may be used for thinning shells, below retirement thickness. 9.3.3.1
9.3.4
9.6
Repair plates shall not be lapped onto lap-welded shell seams, riveted shell seams, other lapped patch repair plates, distorted areas, or unrepaired cracks or defects.
Full fillet weld required on lap patch plates.
Lapped patch repair plates may be used to repair small shell leaks or minimize the potential from leaks. 9.3.4.4
This repair method shall not be used if exposure of the fillet welds to the product will produce crevice corrosion or if a corrosion cell between the shell plate and repair plate is likely to occur.
9.3.4.5
This repair method shall not be used to repair shell leaks if the presence of product between the shell plate and repair plate will prevent gas freeing from the tank to perform hot work.
Repair of Defective Welds 9.6.1
Cracks, lack of fusion and rejectable slag/porosity require repair. Complete removal by gouging-grinding and the cavity properly prepared for welding.
9.6.2
Generally, it is not necessary to remove existing weld reinforcement in excess of that allowed in API-650.
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9.6.3
Unacceptable weld undercut can be repaired by additional weld metal (or grinding), as appropriate. NOTE:
Maximum allowable depth of undercut: a. b.
1/64" on vertical seams 1/32" on horizontal seams
9.6.4
Weld joints that have experienced loss of metal by corrosion may be repaired by welding.
9.6.5
Arc strikes Repair by grinding or welded. If welded, grind flush.
9.7
9.8
9.9
Repair of Shell Penetrations 9.7.2
Reinforcing plates may be added but they must meet API-650 for dimensions and weld spacing.
9.7.3
Reinforcement plates can be installed to the inside wall, provided that sufficient nozzle projection exists for proper weld tie-in.
Addition/Replacement of Shell Penetrations 9.8.1
The requirements of both API 653 and API 650 must be met for shell penetrations.
9.8.6
Penetrations larger than 2" NPS shall be installed with the use of an insert plate if the shell "t" is greater than 0.50" and the material does not meet the current design metal temperature criteria. Additionally, the minimum diameter of the insert plate shall be at least twice the diameter of the penetration or diameter plus twelve inches (12"), whichever is greater.
Alteration of Existing Shell Penetrations 9.9.1
Altered details must comply with API-650.
9.9.2
New bottom installation (above old bottom) and using the "slotted" method through the shell may not now meet spacing requirements. Options for alternate compliance include the following three (3) items: 9.9.2.1
Existing reinforcement plate may be "trimmed" to increase the spacing between the welds, provided the modification still meets API-650.
9.9.2.2
Remove existing reinforcement and install a new pad. "Tombstone" shapes are acceptable. The existing upper half of he reinforcement plate my be used, with a new lower plate installed. A telltale hole must be installed in the new plate. ITAC API 653 Summary, 2007
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9.9.2.3 9.10
The existing penetration (nozzle and pad) may be removed and the entire assembly relocated to the correct elevation.
Repair of Tank Bottoms (Definition see paragraph 3.9) 9.10.1.1
See figure 9-5 for details for welded-on patch plates
9.10.1.2.1
No welding or weld overlays are permitted within the critical zone, except for welding of: a. b. c. d. e. d.
Widely scattered pits. Pinholes Cracks in the bottom plates. Shell-to-bottom weld. Welded-on patch plates Replacement of bottom or annular plate.
9.10.1.2.4
If more extensive repairs are required within the critical zone (than as listed in 9.10.1.2.), the bottom plate (under the shell) shall be cut out and a new plate installed.
9.10.1.2.5
This is a new paragraph that gives the requirements for reinforcement plates.
REVIEW NOTE: Weld Spacing requirements must meet API-650 (3.1.5.4 and 3.1.5.5) requirements. No 3 plate laps closer than twelve inches (12") from each other, from the tank shell, from butt weld annular joints and from joints of the annular ring to normal bottom plates. 9.10.2 Replacement - Entire Bottom 9.10.2.1.1
Non-corrosive material cushion (i.e., sand, gravel or concrete) 3"-4" thick shall be used between the old and new bottoms.
9.10.2.1.2
The shell shall be "slotted" with a uniform cut made parallel to the tank bottom.
9.10.2.1.3
Voids in the foundation (below the old bottom) shall be filled with sand, crushed limestone, grout or concrete.
9.10.2.1.4
Raise elevation of existing penetrations if the new bottom elevation requires a cut through the reinforcement.
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9.10.2.1.5
On floating roof tanks, keep in mind that the floating roof support legs may require revision to conform to new bottom elevation.
9.10.2.2
New bearing plates are required for floating roof leg supports and for fixed roof support columns. Column length revisions are also required on fixed roof tanks.
9.10.2.3
Consider removal of old bottom, or of providing protection from potential galvanic corrosion. NOTE:
See API-RP 651. Also see API-653 (4.4.5.) regarding bottom leak detection.
9.10.2.4
New weld joints in the tank bottom or annular ring shall be spaced at least the greater of 3 inches or 5t from existing vertical weld joints in the bottom shell course.
9.10.2.6
Consideration must be given to Cathotic Protection and leak detection systems when replacing the entire tank bottom.
9.10.3.1
Additional Welded-on Plates New inspection requirements, plates must be MT or PT if the weld spacing requirements can not be met.
9.11
Repair of Fixed Roofs 9.11.1.1 and 9.11.2.2 Same criteria as previously noted/discussed in API-650 relative to: a. b. c. d.
9.12
Plate "t" Roof support structure Loading Roof-to-shell junction
External and Internal Floating. Roofs a. b.
Repair in accordance to original construction drawings. If no original drawings available, use criteria from API-650, Appendix C and H.
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9.13
Repair/Replacement of Floating Roof Seals 9.13.1 Rim mounted seals can be removed, repaired or replaced. Items for consideration are: a. b. c.
Minimize evaporation/personnel exposure by limiting seal segment removal to 1/4 of the seal at one time. Use temporary spacers to keep roof centered. In-service repair may be limited to seal component parts or high positioned vapor seals.
9.13.2 Secondary seals can normally be "in-service" repaired or replaced. 9.13.3 Seal-to-Shell Gap Corrective action includes: a. b. c. d. e.
Adjusting hanger system or primary shoe seal types. Adding foam filler to toroidal seals. Increasing length of rim mounted secondary seals. Replacement (all or part) of the primary system. Adding a rim extension to install secondary seal.
9.13.4 Mechanical Damage: Repair or replace. NOTE:
Buckled parts require replacement, not straightening.
9.13.6 Minimum Allowable roof rim "t" = 0.10" Minimum "t" of new rim plate = 0.1875" 9.14
Hot Taps Installation on existing in-service tanks with shell material that does not require post-weld heat treatment. NOTE:
Connection size and shell "t" limitations are: a. b. c. d.
Six inches (6”) and small-minimum shell “t” 0.1875” Eight inches (8") and smaller-minimum shell "t" 0.25" Fourteen inches (14") and smaller-minimum shell "t" 0.375" Eighteen inches (18") and smaller-minimum shell "t" 0.50"
9.14.1.2
Use low hydrogen electrodes.
9.14.1.3
Hot taps are not permitted on: a. b.
Tank roof Within the gas/vapor space of a tank.
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9.14.2 Hot Tap Procedure Requirements a. b.
Use customer/owner developed-documented procedure. If no documentation is available, API Pub. 2201 applies.
9.14.3 Preparatory Work 9.14.3.1
Minimum spacing in any direction (toe-to-toe of welds) between the hot tap and adjacent nozzles shall be equivalent to the square root of RT (where "R" is tank shell radius, in inches, and "T" is the shell plate "t", in inches.
9.14.3.2
Shell plate "t" shall be taken in a minimum of four (4) places along the circumference of the proposed nozzle location.
9.14.5 Installation Procedure 9.14.5.1
Pre-cut pipe nozzle to shell contour and outside bevel for full penetration weld. (See Fig. 9-6, page 9-12 for details).
9.14.5.2
After pipe nozzle is welded, install the reinforcement (1 piece or 2 pieces). A two piece pad requires a horizontal weld). NOTES:
9.14.5.3
Full penetration weld - pad to nozzle. Limit weld heat input as practical.
Upon weld completion: a. b. c.
9.14.5.4
1. 2.
Conduct NDE as required by procedure. Pneumatically test per API-650 procedure. After valve installation, pressure test (at least 1.5 times the hydrostatic head) the nozzle prior to mounting the hot-tap machine.
Following the hot-tap machine manufacturer's procedure, only qualified operators can make the shell cut.
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SECTION 10 - DISMANTLING AND RECONSTRUCTION 10.1
General 10.1.1 Provides for dismantling and reconstruction of existing welded tanks relocated from their original site. 10.1.2 See Section 12 for hydrostatic and weld requirements.
10.3
Dismantling Methods Cut into any size pieces that are readily transportable to new site. 10.3.2 Bottoms 10.3.2.1
Deseam lapwelds, or cut alongside existing seams (a minimum of 2" from existing welds), except where cuts cross existing weld seams.
10.3.2.2
If most of the bottom is to be reused, cut from shell along line A-A (Fig. 10-1), or if entire bottom is salvaged intact, cut shell along line B-B.
10.3.3 Shells 10.3.3.1
Cut shell by one, or a combination, of the following methods: a.
Cuts made to remove existing welds and HAZ, the minimum HAZ to be removed will be one-half of the weld metal width or 1/4 inch, which ever is less, on both sides of the weld seam.
b.
Any shell ring 1/2 inch thick or thinner may be dismantled by cutting through the weld without removing the HAZ.
c.
Cuts made a minimum of 6" away from existing weld seams, except where cuts cross existing welds.
10.3.3.2
Shell stiffeners, wind girders and top angles may be left attached to shell or cut at attachment welds. If temporary attachments are removed, grind area smooth.
10.3.3.3
Cut shell from bottom plate along line B-B (see Fig. 10-1). The existing shell-to-bottom weld connection shall not be reused unless the entire bottom is to be salvaged intact.
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10.3.4 Roofs 10.3.4.1
Cut roof by lapweld deseaming or alongside (a minimum of 2" from) the remaining welds.
10.3.4.2
Roof structure Remove bolts or deseaming at structural welds.
10.3.5 Piece Marking 10.3.5.1
Shell bottom and roof plates Mark prior to dismantling for ready identification and reconstruction placement.
10.3.5.2
10.4
Punch mark (minimum 2 sets) at matching centers located on top and bottom edges of each shell segment for future proper alignment.
Reconstruction 10.4.2.1
Welding notes as follows: a. b. c.
10.4.2.2
Vertical weld joints should not aligned with joints located in bottom plates. No welding over heat affected zones (from original tank welds), except where new joints cross original joints. Refer to Fig. 9-1 for weld spacing.
Tank and Structural Attachment Welding Use processes specified in API-650.
10.4.2.3
Specific welding notes: a.
No welding is allowed when parts to be welded are wet from rain, snow or ice or when rain or snow is falling, or during high wind conditions (unless the work is shielded). Caution this is a common practice and should be avoided.
b.
No welding is permitted when the base metal is below 0°F.
c.
If the base metal temperature is between 0° and 32°F or the metal "t" is in excess of 1", the base metal within 3" of welding shall be pre-heated to approximately 140°F.
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10.4.2.4
As normal, each layer of weld deposit is to be cleaned of slag or other deposits.
10.4.2.5
As in API-650, the maximum acceptable undercutting is 1/64" for vertical butt joints and 1/32" for horizontal butt joints.
10.4.2.7
Same tack weld provisions as API-650, i.e.: a. b.
Vertical , manual tacks - Remove. Vertical, submerged tacks - If sound, clean only.
NOTE: 10.4.2.8
If weldable primer coatings exist, they must be included in procedure qualification tests. NOTE: welding.
10.4.2.9
Tack welds left in place must have been applied by a qualified welder.
All other coating must be removed prior to
Low-hydrogen electrodes required on manual metal-arc welds, including the shell to bottom attachment or annular plate ring.
10.4.3 Bottoms 10.4.3.2
Weld shell to bottom first (except for door sheets) before weldout of bottom plates is started.
10.4.4 Shells 10.4.4.1
Same fit-up/welding procedures and values as allowed in API-650 for vertical joints: a. b.
Over 5/8" thick - misalignment shall not exceed 10% of "t" (maximum 0.125"). Under 0.625" thick - misalignment shall not exceed 0.06". NOTE:
10.4.4.2
Complete vertical welding before roundseam below is welded.
Horizontal joints Upper plate shall not project over lower by more than 20% of upper plate "t"(with 0.125" maximum).
10.4.4.3
Material over 1.50" thick a minimum pre-heat of 200°F is required. ITAC API 653 Summary, 2007
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10.4.5 Roofs There are no special stipulations, except that structural members must be reasonably true to line and surface. 10.5
Dimensional Tolerances 10.5.2.1
Allowable maximum out-of-plumbness (top of shell relative to shell bottom) shall not exceed 1/100 of total tank height, with a maximum of 5" this dimension also applies to roof columns.
10.5.3 Roundness See values and measurement locations on Table 10-2. 10.5.4 Peaking Shall not exceed 0.50". 10.5.5 Banding Shall not exceed 1.00". NOTE: Somewhat more lax than API-650. 10.5.6 Foundations Same specifications as listed under API-650.
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SECTION 11 - WELDING 11.1
Welding Qualifications 11.1.1
Weld procedure specifications (WPS), welders and operators shall be qualified in accordance with Section IX of the ASME Code. API 653 now allows the use of SWPS’s, AWS D1.1 and AW D1.6 for the welding of ladder and platform assemblies, handrails and stairways, as well as miscellaneous assemblies. But not for attachment welds to the tank.
11.1.2
Weldability of steel from existing tanks must be verified. If the material specification is unknown or obsolete, test coupons for the procedure qualification shall be taken from the actual plate to be used. SECTION 12 - EXAMINATION AND TESTING 12.1.1.1
NDE shall be performed in accordance with API 650, plus API 653 supplemental requirements.
12.1.1.2
Personnel performing NDE shall be qualified in accordance with API 650.
12.1.1.3
Acceptance criteria shall be in accordance with API 650. NOTE: Appendix "F" is not mentioned.
12.1.1.5
Appendix G is mentioned fro qualifying personnel and procedures when using MFL.
12.1.2 Shell Penetrations 12.1.2.1
UT lamination check required for: a. b.
Adding reinforcement plate to an unreinforced penetration. Installing a hot-tap connection.
12.1.2.2
Cavities from gouging or grinding to remove reinforcement pad welds require either a magnetic particle or liquid penetrant test.
12.1.2.3
Completed welds attaching nozzle to shell or pad to shell and nozzle neck shall be examined by a magnetic particle or liquid penetrate test. Consideration should be given for extra NDE on hot taps.
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12.1.2.4
Complete welds in stress relieved components require magnetic particle or liquid penetrate testing (after stress relief, but before hydrostatic test).
12.1.3 Repaired Weld Flaws 12.1.3.1
Cavities from gouging or grinding to remove weld defects shall be either a magnetic particle or liquid penetrate tested.
12.1.3.2
Completed repair of butt welds shall be examined over their full length by UT or radiographic methods.
12.1.4 Temporary and Permanent Attachments to Shell Plates 12.1.4.1
A ground area resulting from the removal of attachments requires a visual test.
12.1.4.2
Completed welds on permanent attachments shall be examined by MT or PT, groups IV-VI, excluding the shell to bottom weld.
12.1.5 Shell-to-Shell Plate Welds New welds attaching shell plate to shell plate require visual and radiographic examination. Additionally, plate greater than 1", the backgouged surface of root pass and final pass (each side) shall be examined over its full length by a magnetic particle or liquid penetrate test. 12.1.5.2
New welds on new shell plate to new shell plate are to be examined and radiographed to API 650.
12.1.6 Shell-to Bottom
12.2
12.1.6.1
Joints shall be inspected over its entire length by a right angle vacuum box and a solution film, or by applying light diesel oil. (“Diesel” test technique).
12.1.6.2
An air pressure test may be used to check the shell-tobottom weld.
12.1.8.2
(New Paragraph) deals with lap welded shell patches.
Radiographs Number and location - Same as API-650, plus the following additional requirements:
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12.2.1.1
Vertical Joints a. b. c.
12.2.1.2
Horizontal Joints a. b. c.
12.2.1.3
New plate to new plate: Same as API 650. New plate to existing plate: Same as API 650, plus one (1) additional radiograph. Existing plate to existing plate: Same as API 650, plus one (1) additional radiograph.
New plate to new plate: Same as API 650. New plate to existing plate: Same as API 650, plus one (1) additional radiograph for each 50 feet of horizontal weld. Existing plate to existing plate: Same as API 650, plus one (1) additional radiograph for each 50 of horizontal weld..
Intersections a. b. c.
New plate to new plate: Same as API 650. New plate to existing plate: Shall be radiographed. Existing plate to existing plate: Shall be radiographed.
12.2.1.4
Each butt-weld annular plate joint - Per API-650.
12.2.1.5
For reconstructed tanks 25 percent of all junctions shall be radiographed.
12.2.1.6
New and replaced shell plate or door sheet welds: 12.2.1.6.1
Circular - Minimum one (1) radiograph
12.2.1.6.2
Square or Rectangular:
One (1) in vertical, one (1) in horizontal, one (1) in each corner. NOTE:
12.2.1.8
All junctions between repair and existing weld shall be radiographed. If defects are found, 100% is required on weld repair area.
For penetrations installed using insert plates as described in 9.8.2, the completed butt welds between the insert plate and the shell plate shall be fully radiographed.
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12.2.2 Criteria Acceptance If a radiograph of an intersection between new and old weld detects unacceptable flaws (by current standards) the weld may be evaluated according to the as built standard. 12.3
Hydrostatic Testing 12.3.1.1
A full hydrostatic test, held for 24 hours, is required on: a. b.
c.
A reconstructed tank. Any tank that has had major repairs or alterations (See 3.23.) unless exempted by 12.3.2 for the applicable combination of materials, design and construction features. A tank where an engineering evaluation indicates the need for the hydrostatic test.
12.3.2 Hydrostatic not Required Conditions 12.3.2.1
A full hydrostatic test of the tank is not required for major repairs and major alterations when: a. b.
12.3.2.2
The repair has been reviewed and approved by an engineer, in writing. The tank owner or operator has authorized the exemption in writing.
Shell Repair
12.3.2.2.1
Weld procedures for shell repair must include impact testing.
12.3.2.2.3
New requirements, new shell materials must API 650 7th edition or later, must meet requirements for brittle fracture, stress must not be more than 7,000 psi as calculated from the new formula given in this paragraph. S = 2.6 H D G t S= H= t= D= G=
shell stress in pounds per square foot tank fill height above the bottom of repairs or alteration in feet shell thickness at area of interest in inches tank mean diameter in feet specific gravity of product
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12.3.2.2.5
New radiography requirements, the finished weld in the shell plates shall be fully radiographed.
12.3.2.2.8
A big change in this section, door sheets shall comply with the requirements for shell plate installation, except they shall not extend to or intersect the bottom-to-shell joint.
12.3.2.3
Bottom Repair Within the Critical Zone
12.3.2.3.1 12.5
Now allows UT to be used on annular plate butt welds
Measured Settlement (During Hydro) 12.5.1.1 12.5.1.2
When settlement is anticipated, the tank being hydrotested must have a settlement survey. Initial Settlement Survey: With tank empty, using the number of bottom plate projections as elevation measuring points (N), uniformly distributed around the circumference. FORMULA: N=D/10 Where: a.
N=
b.
D=
NOTE:
minimum number of measurement points (not less than 8). The Maximum spacing between measurement points shall be 32 feet. tank diameter (in feet). See Appendix B for evaluation and acceptance.
12.5.2 Survey During Hydro Measure at increments during filing and at 100% test level. NOTE:
Excessive settlement (per Appendix B) shall be cause to stop test, investigate and/or repair.
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SECTION 13 - MARKING AND RECORD KEEPING 13.1.1 API-653 reconstructed tanks require nameplate with letters and numerals must be a minimum of 5/32" high. The following information is required a. b. c. d. e. f. g. h. i. j. k. l. m.
Reconstructed to API-653. Edition/revision number. Year reconstruction completed. If known, the as built standard and original date. Nominal diameter Nominal height. Design specific gravity of product stored. Maximum permissible operating liquid level. Contractor's serial and/or contract number. Owner/operator identification number. Material for each shell course. Maximum operating temperature. Allowable stress used in calculations for each course.
13.1.2 New nameplate Shall be attached to the tank shell adjacent to existing nameplate. 13.2
Record keeping Tanks evaluated, repaired, altered or reconstructed to API-653 require the following owner/operator records: a. b. c.
Component integrity evaluation, including brittle fracture considerations. Re-rating data (including liquid level). Repair and alteration considerations. 13.2.1.3
Additional support data including, but not limited to, information pertaining to: a. b. c. d. e. f. g. h. i. j. k. l. m.
Inspections (including "t" measurements). Material test reports/certifications. Tests. Radiographs (to be retained for at least one year). Brittle fracture considerations. Original construction data. Location and identification (owner/operator number, serial number). Description of tank (diameter, height and service). Design conditions (i.e., liquid level, specific gravity, stress and loading). Shell material and thickness (by course). Tank perimeter elevations. Construction completion record. Basis for hydrostatic test exemption
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13.3
Certification Documentation of reconstruction in accordance with API-653 is required. (See Fig. 13-2). APPENDIX B EVALUATION OF TANK BOTTOM SETTLEMENT B.1.1 Common methods to monitor potential problem: a. b. c.
Initial settlement survey, at erection and hydro. Planned frequency, per soil settlement predictions For existing tanks (with no settlement history), monitoring should be based on visual observations and prior service history.
B.1.2 Excessive settlement requires evaluation/interpretation of survey data. Tank should be emptied and releveling repair conducted. B.1.3 Correcting shell and bottom settlement problems include the following techniques: a. b. c. B.2
Localized bottom plate repair. Partial releveling of tank periphery. Major releveling of shell and bottom.
Types of Settlement B.2.1 Elevation measurements around the circumference and across the tank diameter are the best method for evaluating shell and bottom settlement problems. Local depressions may require other techniques. B.2.2 Shell Settlement Evaluation Tank settlement results from either one or a combination of the following three (3) settlement components: B.2.2.1
Uniform settlement. May vary in magnitude, depending on soil characteristics. It is the least severe or threatening settlement problem. It does not introduce stress in tank structure, but does present a potential problem for piping, nozzles and attachments.
B.2.2.2
Planar Tilt (rigid body tilting). Rotates the tank in a tilted plane. This tilt will cause an increase in the liquid level and an increase in the shell hoop* stress. Can also cause binding of peripheral seals in a floating roof and inhibit roof travel. This may be visible in the form of elongation of top shell ring in floating roof tanks. Can affect tank nozzles that have piping attached to them. ITAC API 653 Summary, 2007
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B.2.2.3
Differential Settlement (out of plane). Due to a tank shell being a rather flexible structure, non-planer configuration type settlement often occurs. Potential Problems: a. b. c. d. e.
B.2.2.4
Increased stress levels. Elongation of upper shell. Floating roof travel interference and potential seal damage or roof "hang-up". Development of shell flat spots. High nozzle/piping stress levels.
Uniform and rigid body tilt can cause problems as noted, overall integrity of the shell and bottom are more likely to be impacted by differential settlement. Therefore, this type problem becomes very important to determine severity and evaluate properly. Common approach for settlement survey: a. b. c.
Obtain transit survey from the correct number of evenly spaced points. Determine magnitude of uniform and rigid body tilt from each point on tank periphery. Develop a graphic line point representation of the involved data.
NOTE:
B.2.2.5
Develop values (showing elevation differences) by comparing transit measurement readings by use of provided decimal chart. A stress analysis method is now included in this paragraph.
Refer to B.3.2 for method of determining acceptable settlement condition or values.
B.2.3 Edge settlement B.2.3.1
Occurs when tank shell settles sharply around the periphery, resulting in deformation of the bottom plate near the shell junction. (See Fig. B-4 for pictorial view).
B.2.5 Localized Bottom Settlement (Remote from Shell) B.2.5.1
Depressions/bulged that occur in a random matter, remote from shell.
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B.2.5.2
Acceptability dependent upon: a. b. c.
Localized bottom plate stresses. Design/quality of lap welds. Void severity below the bottom plate.
NOTES:
B.3
1. 2.
Not normally seen as extreme problem. When occurring, normally associated with new tank where no or insufficient load bearing soil test borings have been made.
Determination of Acceptable Settlement B.3.1 General Greater settlement may be acceptable in tanks with a successful service history than new construction standards allow. Each condition must be evaluated, based on service conditions, construction materials, soil characteristics, foundation design and prior service history. B.3.2 Shell Settlement Determine the maximum out-of-plane deflection. The formula for calculating the maximum permissible deflection is shown on page B-4. Requires technical assistance.
B.4
Repairs If conditions beyond acceptable conditions are found, a rigorous stress analysis should be performed to evaluate the deformed profile, or repairs conducted. Various repair techniques are acceptable. (See Section 9.10 for helpful details). Several new figures have been added to Appendix B, however the bases for the new figures and requirements have been challenged. There is no bases for the information in the figures.. The user is left to his own devices as how to use this information.
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APPENDIX C CHECKLISTS FOR TANK INSPECTION Tables C-1 and C-2 are sample checklists illustrating tank components and auxiliary items that deserve consideration during internal/external inspections. Use these as guidance items only. Numerous items need not be checked by the inspector, but rather by plant personnel. Table C-1 (In Service Inspection checklist) includes 111 separate items. Table C-2 (Out-of-Service Inspection Checklist) includes 248 separate items. APPENDIX D AUTHORIZED INSPECTOR CERTIFICATION This Appendix was rewritten in the 4th Addenda to API 653. D.1
Written exam. based on the ‘current’ API 653 Body of Knowledge.
D.2
Educational requirements for the API 653 Authorized Inspector.
D.5
Recertification requirements for the API 653 Authorized Inspector. D.5.3 The requirements for re-examination are listed, after two re-certifications, 6 years, each inspector shall demonstrate knowledge of revisions to API 653. APPENDIX E TECHNICAL INQUIRIES
This section is a listing of how to contact the API 653 committee. The Technical Inquiry Responses have also been listed, but are not a part of the exam. This information is useful in actual application of API 653.
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APPENDIX F NDE REQUIREMENTS SUMMARY This section is a summary of the requirements for NDE personnel and procedures, API 650, ASME Section V and VIII, and ASNT are listed. This is a very good section that will be useful to the user. APPENDIX G QUALIFICATION OF TANK BOTTOM EXAMINATION PROCEDURES AND PERSONNEL This appendix was established in the first addenda to edition three of API 653 and outlines procedure and qualifications for floor scanning, G.2 Definitions G.2.1 essential variables: Variables in the procedure that cannot be changed without the procedure and scanning operators being re-qualified. G.2.2 examiners: Scanning operators and NDE technicians who prove-up bottom indications. G.2.3 bottom scan: The use of equipment over large portions of the tank bottom to detect corrosion in a tank bottom. One common type of bottom scanning equipment is the Magnetic Flux Leakage (MFL) scanner. G 2.4 authorized inspection agency: Organizations that employ an aboveground storage tank inspector certified by API (see 3.4). G.2.5 non-essential variables: Variables in the procedure that can be changed without having to re-qualify the procedure and/or scanning operators. G.2.6 qualification test: The demonstration test that is used to prove that a procedure or examiner can successfully find and prove-up tank bottom metal loss.
G.2.7 scanning operator (or operator): The individual that operates bottomscanning equipment. G.2.8 sizing (or prove-up): The activity that is used to accurately determine the remaining bottom thickness in areas where indications are found by the bottom scanning equipment. This is often accomplished using the UT method. G.2.9 tank bottom examination: The examination of a tank bottom using special equipment to determine the remaining thickness of the tank bottom. It includes both the detection and proveup of the indications. It does not include the visual examination that is included in the internal inspection. G.2.10 tank bottom examination procedure (TBP): A qualified written procedure that addresses the essential and non-essential variables for the tank bottom examination. The procedure can include multiple methods and tools, i.e., bottom scanner, hand scanner, and UT prove-up.
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G.2.11 tank bottom examiner qualification record (TBEQ): A record of the qualification test for a specific scanning operator. This record must contain the data for all essential variables and the results of the qualification test. G.2.12 tank bottom procedure qualification record (TBPQ): A record of the qualification test for a tank bottom examination procedure. This
record must contain the data for all essential variables and the results of the qualification test. G.2.13 variables or procedure variables: The specific data in a procedure that provides direction and limitations to the scanning operator. Examples include; plate thickness, overlap of adjacent bottom scans, scanning speed, equipment settings. ect.
G.3
An explanation of Tank Bottom Examination procedures
G.4
Requirements for Tank Bottom Examiners
G.5
Qualification Testing, including test plates, standards and variables.
APPENDIX S AUSTENITIC STAINLESS STEEL STORAGE TANKS S.1
This section works with AI 650, Appendix S.
ITAC API 653 Summary, 2007
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API 653 CODE QUIZ
1.
In case of conflict between API-12C, API-650 and API-653 standards involving "in-service" AST's, which of the three codes will govern? a. b. c.
2.
Which of the following have the ultimate responsibility for complying with API-653 standard provisions? a. b. c. d.
3.
On-site Inspector Contractor Involved Owner/operator of equipment Relevant State or Federal Agency
A condition that exists when it cannot be demonstrated that the material of a component satisfies the definition of recognized toughness. a. b. c. d.
4.
API-12C API-650 API-653
Charpy Impact Test Recognized Toughness As-built Standard Unknown Toughness
What is the joint efficiency of a lap riveted joint with one (1) row of rivets? a. b. c. d.
45% 60% 75% 80%
ITAC API 653 Summary, 2007
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ITAC 5.
All prior reported brittle fracture tank failures have occurred under which of the following conditions/situations? a. b. c. d.
6.
When external UT "t" measurements are used to determine a rate of general, uniform corrosion (relevant to shell integrity) which of the following values cannot be exceeded? a. b. c. d.
7.
10 years maximum 20 years maximum 5 years (after commissioning), or at 5 year intervals (where corrosion rate is not known). Five years or RCA/4N, whichever is more.
What primary factor determines the interval between internal and external inspections? a. b. c. d.
8.
Atmospheric temperature of 20°F or lower. During a hydro test where the test water was 200°F or hotter. Shortly after erection, following a repair/alteration, first cold weather filling or change to lower temperature service. Where a testing medium other than water was used.
Jurisdictional regulations Tank service history, unless special reasons indicate an earlier inspection is required. Known (or suspected) corrosion activity of product. Change of service to a product with a specific gravity 10% higher than prior stored product.
What is the minimum dimension for a shell ring replacement piece or segment? a. b. c. d.
The actual area requiring renewal, plus 6" on all four surrounding sides. 12" or 12 times the "t" of the replacement plate, whichever is greater. 10% of the individual ring segment involved. 20% of the individual ring segment involved.
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ITAC 9.
Which of the areas described below are considered to be the "critical zone" involving tank bottom repair? a. b. c. d.
10.
Select the minimum number of "t" measurements required (along the circumference of any proposed "hot-tap" nozzle location): a. b. c. d.
11.
One (1) on horizontal centerline (3" from edge) on each side of proposed shell opening cut. Four (4) Eight (8) Establishment of both a minimum and average "t" over the entire nozzle installation area.
What type of contour cut (if any) and what degree of bevel (if any) is required on the nozzle "barrel" end that is to be joined to shell during a "hot-tap". a. b. c. d.
12.
Within the annular ring, within 12" of shell, or within 12" of inside edge of annular plate ring. Any area where 3–plate laps are located Within 36" (measured vertically) from any shell penetration above. Within 3" from the shell on the bottom plates
No contour cut required, 30° outside bevel. No contour cut required, 45° outside bevel. Cut to shell contour and outside beveled for full penetration attachment weld. No contour cut required. 1/8" corner radius (minimum).
When reconstructing tank shells with a material "t" exceeding 1.50", what minimum pre-heat is specified? a. b. c. d.
No preheat required, if air temperature exceeds 70°F. 200°F. 225°F. 300°F.
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ITAC 13.
In re-erecting a tank shell, what length "sweep-board" and what are maximum allowable values for weld seam peaking? a. b. c. d.
14.
Welding procedure Specs (WPS) are established in Section 11 of API-653. Welders/operators must be qualified in accordance with which of the codes listed, if the weld is a new shell to nozzle weld. a. b. c. d.
15.
0.50" (1/2") with 36" horizontal sweep board? 0.25" (1/4") on verticals; 0.50" (1/2") on horizontal with 36" board 0.75" (3/4") with 48" board. 1.00" (1") with 48" board.
AWS Section V ASME Section VIII ASME Section IX ASME
API-653 (Section 12) requires greater radiographic examination of tank shell welds than does API-650. Relevant to new or repaired vertical joints in existing shell plates, how many radiographs are required? a. b. c. d.
Twice those required by API-650. API 650 requirements plus one (1) in every joint. One (1) for each welder or operator involved on each ring. Two (2) for each welder or operator involved on each ring for all plate thicknesses.
The following information applies for questions 16 through 20 below: An internal inspection is performed on an aboveground storage tank 44 feet tall, 40 foot fill height, 112 feet diameter, light oil (specific gravity = 1) service, sand pad with a reinforced concrete ring wall foundation. There is one area of general corrosion on the north side of the shell 38 inches wide and 20 inches tall. (The tank was built to API 650, 7th Edition). 16.
Calculate the minimum thickness for the first course based on product alone. a. b. c. d.
7/8" 3/4" 5/8" 1/2" ITAC API 653 Summary, 2007
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ITAC 17.
Calculate the "L" length for an area of general corrosion found ten feet from the bottom on the north side of the shell, t2 = .125 inches. a. b. c. d.
18.
There are four pits lined vertically on the south side of the tank in the first course. The pits measure 1", 1.250", 1." and .500" in length along a vertical line 8" long. The pit depth is approximately 0.255" each. a. b. c. d.
19.
A repair is required. Because of the vertical pits, no repair is required. If the pit depth is only .130 inches the pits may be ignored. Scattered pits may be ignored.
A bulge is found on the tank floor, the diameter of the bulge is 30 inches, what is the maximum permissible height for the bulge? a. b. c. d.
20.
3.7" 10" 13.84" 40"
11.1" .463" .962 1.11"
An area of edge settlement in the tank bottom 6 feet from the tank shell has sloped down and settled. The settlement measures 2 inches at the deepest point. The edge settlement area has bottom lap welds approximately parallel to the shell. a. b. c. d.
A more rigorous stress analysis must be performed. The area must be repaired. Sloped edge settlement is usually no problem The area should be documented and checked during the next inspection.
ITAC API 653 Summary, 2007
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API 653 CODE QUIZ ANSWER KEY 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16.
c c d a c c b b d b c b a d b d
{Paragraph 1.1.2 page 1-1} {Paragraph 1.2 page 1-1} {Paragraph 3.25 page 3-2} {Table 4-3 page 4-7} {Paragraph 5.2.2 page 5-1} {Paragraph 6.3.3.2 (b) page 6-1} {Paragraph 6.2.2 page 6-1} {Paragraph 9.2.2.1 page 9-1} {Paragraph 3.9 page 3-1} {Paragraph 9.14.3.2 page 9-11} {Paragraph 9.14.5.1 page 9-12} {Paragraph 10.4.4.3 page 10-3} {Paragraph 10.5.4 page 10-3} {Paragraph 11.1.1 page 11-1} {Paragraph 12.2.1.1 page 12-2} (1/2") {Paragraph 4.3.3 page 4-3} tmin = 2.6 (H-1) DG SE tmin = ? D = 112 H = 40 G=1 S = 23,600 E=1 tmin = 2.6 (40-1) (112) (1) 23,600 tmin = 11,356.8 23,600 tmin = .481 inches (rounded to 1/2 inch)
ITAC API 653 Summary, 2007
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API 653 CODE QUIZ ANSWER KEY
17.
c
L = 3.7
Dt2
(13.84") (Paragraph 4.3.2.1 Page 4-2) L = 3.7(112)(.125) L = 3.7 14
L - 3.7(3.74)
L = 13.84 inches
18. a (A repair is required.) Paragraph 4.3.2.2 Page 4-3) Add the pit diameters 1”+ 1.25” + 1” + .500” = 3.75” (More than allowed in an 8” area) The pit depth exceeds one-half the minimum acceptable tank shell thickness. 19. b (.463") (Paragraph B.3.3 Page B7) R = Diameter divided by 2, in feet, 30” divided by 2 - 15” divided by 12 = 1.25 feet. B = .37R B = .37 (1.25) B = .463 inches 20.
d
(The area should be documented and checked during the next inspection.) Figure B-10, Page B-9
Using figure B-10 the area is acceptable, it should be documented.
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ITAC API 653 Summary, 2007
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Section 2 650 Sum 2007
API STANDARD 650 WELDED STEEL TANKS FOR OIL STORAGE Tenth Edition, November, 1998 Addendum 1, January, 2000 Addendum 2, November, 2001 Addendum 3, September, 2003 Addendum 4, December, 2005 SECTION 1 - SCOPE 1.1
General 1.1.1
This standard covers material, design, fabrication, erection and testing requirements for vertical, cylindrical, aboveground, closed and open-top, welded steel storage tanks in various sizes and capacities for internal pressures approximating atmospheric pressure.
NOTE 1:
This standard covers only tanks whose entire bottom is uniformly supported and only tanks in non-refrigerated service that have a maximum operating temperature of 200° F.
NOTE 2:
A bullet (•) at the beginning of a paragraph indicates that there is an expressed decision or action required of the purchaser.
APPENDIXES:
Listed below apply to specifics that most often apply to new tank erections whereby Inspector knowledge must be reasonably thorough.
1.1.3
The purchaser will specify SI dimensions or US customary dimensions.
1.1.6
Appendix B: Design and construction of foundations under flat bottom oil storage tanks.
1.1.7
Appendix C: Requirements for pan-type, pontoon-type and double decktype external floating roofs.
1.1.12 Appendix H: Requirements for an internal roof in a tank that has a fixed roof at the top of the tank shell. 1.1.14 Appendix J: Requirements covering the complete shop assembly of tanks not more than 20 feet in diameter. 1.1.15 Appendix K: An example of the application of the variable-design-point method to determine shell-plate thickness. NOTE:
In larger tanks (over 200 feet in diameter), use of higher tensile strength steel, plus increased NDE procedures reduces plate "t". ITAC API 650 Summary, 2007
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1.1.17 Appendix M: Requirements for elevated temperature product storage up to 500° F. NOTE:
Appendixes A, D, E, F, L, N, O, P, R, S and T cover requirements on specifics that apply much less frequently from an inspection perspective.
1.1.21 Appendix R: Load Equations 1.1.22 Appendix S: Requirements for the construction of austenitic stainless steel tanks. 1.1.23 Appendix T: Requirements for inspection (summary). 1.1.24 Appendix U: Requirements for UT examination, in lieu of radiography. 1.1.25 Appendix V: Requirements for external pressure (vacuum). 1.2
Limitations a. b. c. d.
API 650 stops at the face of the first flange. API 650 stops at the first sealing surface. API 650 stops at the first threaded connection. API 650 stops at the first circumferential weld. SECTION 2: MATERIALS
2.1
General Material Requirements 2.2.1.1
Refer to 2.2.2 ASTM Standards for acceptable tank steel plate requirements.
2.2.1.2
Plate for shells, roofs and bottoms may be on an edgethickness basis or on a weight (pounds per square foot) basis. Example: 3/16" plate (0.1875" or 7.65 lbs.) or 1/4" plate (0.250" or 10.4 lbs.), etc. 2.2.1.2.3
Whether an edge-thickness or a weight basis is used, an underrun of not more than 0.01" from the computed design thickness or the minimum permitted thickness is acceptable.
NOTE:
Most common plates used: 1. 2. 3.
ASTM A-283 Gr. C ASTM A-36 Alternate Design Basis (ADB) tanks (See Appendix K) require higher tensile strength material.
ITAC API 650 Summary, 2007
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2.2.2
New ASTM specification used.
2.2.8
Special plate requirement or testing: a. b.
Customer may require a set of charpy v-notch impact specimens. Special toughness requirements may be specified.
2.2.9.3
Normal design metal temperature shall be assumed to be 15°F above the lowest 1-day mean ambient temperature in the locality where the tank is to be installed. (See Fig. 2-2).
2.2.9.4
Plate used to reinforce shell openings shall be of the same material as the shell plate to which it is attached. NOTE:
2.2.10.4
Also must be at least as thick as primary plate! Shell nozzles and manway materials shall be equal or greater yield and tensile strength and shall be compatible with the shell material.
The manufacturer must furnish mill test data, including the required toughness at design metal temperature.
NOTE:
The 4th Addendum excluded paragraphs : 2.5.5.4 2.6 2.6.1 2.6.2 2.7 2.8 2.8.1 2.8.2
Impact Testing Requirements Flanges Flange Descriptions Flange Descriptions Bolting Welding Electrodes AWS 5.1 AWS 5.5
THIS IS A TYPOGRAPHICAL ERROR. THESE PARAGRAPHS ARE STILL INCLUDED IN API 650 AND CAN BE ON THE EXAM. 2.8
Welding Electrodes For welding materials with a minimum tensile strength less than 80 KSI per square inch, manual arc-welding electrodes shall conform to the E60 and E70 series, AWS 5.1.
ITAC API 650 Summary, 2007
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SECTION 3: DESIGN 3.1
Joints (Tank Design) 3.1.1-3.1.1.8 No detailed discussion. Be knowledgeable about the eight (8) types listed.
3.1.4
3.1.3.2
Tack welds are not considered as having any strength value in the finished structure.
3.1.3.3
On plates 3/16" thick, a full fillet weld is required. On plates thicker than 3/16", the weld shall not be less than one-third the "t" of the thinner plate at the joint, with minimum of 3/16".
3.1.3.4
Single lap welds - bottom and roof plates only.
3.1.3.5
Lap-weld joints shall be lapped not less than "5t" of the thinner plate, but need not exceed 1".
AWS weld symbols are required on drawings. 3.1.5.2
3.1.5.3
Vertical Shell Joints a.
Verticals shall be butt joints with complete penetration and fusion that will provide the same quality of deposited metal on both outside and inside weld surfaces.
b.
Vertical joints (in adjacent shell courses) shall not be in alignment. An off-set from each other of "5t" (where "t" is the thickest course at the point of offset).
Horizontal shell joints Same criteria as for verticals above, except that top angles may be double-lap welded.
3.1.5.4
Lap-welded Bottom Joints a.
3-plate laps shall not be closer than 12" from each other, from the tank shell, from butt-welded annular plate joints and from joints between annular plate and bottom.
b.
Welded on top side only (full fillet only).
c.
On other than annular (doughnut) rings the plate under the shell must have the outer end of the joint fitted and welded to form a smooth bearing for the shell plate. Note: Called a "BREAK-OVER." (Fig 3.3.b) ITAC API 650 Summary, 2007
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NOTE:
3.1.5.5
Butt-weld bottom joints (i.e., normally annular ring) a. b. c. d.
3.1.5.6
Parallel edges - either square or v-grove beveled. If square, root opening not less than 1/4". Minimum 1/8" thick back-up strip required. A 12" minimum space from each other or tank shell also applies.
Annular ring joints - complete penetration and fusion NOTE:
3.1.5.7
b. c. d. e.
If shell is 1/2" thick or less - Fillets not more than 1/2" or less than the nominal "t" of the thinner plate joined. Annular plate requirements. Two (2) weld passes (minimum) are required. Shell-to-bottom weld size around low-type reinforcing plates. Bottom extension dimension change around low-type reinforcing plates.
Roof and Top-Angle Joints a.
Welded top side only with continuous full-fillet. Butt welds are also permitted. Top angle (horizontal leg) may extend either inside or outside.
b. 3.2
A 2" minimum projection beyond outside edge of shell (i.e., bottom extension). See Par. 3.5.2).
Shell-to-Bottom Fillet Welds a.
3.1.5.9
When annular plates are used or required, butt welding is required with a minimum distance of 24" between shell and any bottom lap seam.
Design Considerations All new sections dealing with added design factors, external loads, protective measures, external pressure (Appendix V) and other special considerations.
3.4
Bottom Plates a. b.
3.5
A minimum nominal "t" of 1/4" (10.2 lbs. per sq. ft.), exclusive of any corrosion allowance (CA). A 2" minimum width to project beyond outside edge of shell, on lap weld bottoms (i.e., bottom extension).
Annular Bottom Plates a. b.
Annular bottom plates must be 24 inches wide. A 2 inch projection beyond the outside of the shell. ITAC API 650 Summary, 2007
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3.6
Shell Design Shell designed on basis that tank is filled to a level "H" (fill level) with a specific gravity (SG) product value furnished by customer. NOTE:
Normally designed to be filled with water (i.e., SG of 1.0).
3.6.1.7
Manufacturer must furnish drawing that lists: a. b. c. d.
3.6.2
Allowable Stress - Be familiar with Table 3-2 for plate specifications, yield/tensile strength and stress involved. NOTE:
3.6.3
Required shell "t" (including CA) for design product and hydro test. Nominal "t" used, (i.e.; shell "t" as constructed). Material specification. Allowable stresses.
ASTM A-283, A-285 (GR. C.) and A-36 are the most common.
One Foot Method - Calculates the "t" required at design points 1 foot above the bottom of each shell course. *Not allowed for shells greater than 200 feet in diameter. Formula: td = 2.6D(H-1)G + CA (Design Shell Thickness) Sd Formula: tt = 2.6D(H-1) St NOTE:
3.7
See 3.6.3.2 for details as to actual values or relationship of items shown in the formula above.
Shell Openings 3.7.1.6
Manway necks, nozzle necks and shell plate openings shall be uniform and smooth, with the corners rounded, except where the surfaces are fully covered by attachment welds. NOTE:
3.7.2.1
1/8" corner radius for 2" and smaller nozzle. 1/4" corner radius for larger nozzle sizes.
No reinforcement required for nozzles 2" and smaller.
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3.7.2.2
By design, nozzle necks (i.e., outside extension, within the shell plate "t" and inside extension) may provide the necessary reinforcement. NOTE:
For manway and nozzle design values/fabrication details, be familiar with and able to select the proper values from the following data sheets: 1. 2.
3.7.3
Fig. 3-4A, 3-4B, 3-5 and 3-6. Tables 3-3, 3-4, 3-5, 3-6, 3-7, 3-8, 3-9 and 3-10.
Spacing of Welds Around Connections This paragraph and the next three paragraphs confuse the weld spacing issue. A great deal of confusion has been relieved with the addition of figure 3-22, minimum weld requirements for openings in shells according to section 3.7.3, see page 3-49.
3.8
3.7.4.2
Paragraphs on stress relief of materials.
3.7.4.5
Hold times for stress relieving temperatures.
Shell Attachments (i.e., surface items such as angles, clips and stair treads). 3.8.1.2
3.8.5
Roof Nozzles - See Fig. 3-12, 3-13 and 3-14. NOTE:
3.9.6 and 3.9.7
Remember note on bottom of Fig. 3-16. "When the roof nozzle is used for venting, the neck shall be trimmed flush with the roof line".
Primary/Secondary Wind Girders or Stiffeners: See Fig. 3-17 for typical stiffening ring sections. NOTE:
3.10
Permanent attachment welds shall not be closer than 3" from horizontal shell joint seams, nor closer than 6" from vertical joints, insert-plate joints or reinforcement-plate fillet welds.
Intermediate wind girders cannot be attached within 6" of a horizontal shell joint.
Roofs 3.10.1 Refer to fixed roof types. 3.10.2.1
Roofs and structure designed to support dead load (i.e., roof deck and appurtenances), plus a uniform live load of not less than 25 lbs. per sq. ft. of projected area. (See Appendix R). ITAC API 650 Summary, 2007
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3.10.2.2
Roof plates - minimum nominal "t" of 3/16" (7.65 lbs. per sq. ft., 0.180" plate or 7 gauge sheet). NOTE:
Self-supported roofs may require thicker plate.
3.10.2.3
Supported cone roof plates shall not be attached to the supporting members, unless approved by the purchaser.
3.10.2.4
Internal-External structural members must have a minimum nominal "t" (in any component) of 0.17".
3.10.2.5
Roof plate weld attachment to top angle. NOTE:
Refer to Glossary, Frangible Joint, Items "a, b and c" -See weld size restrictions/conditions. (3/16")
3.10.2.6
Frangible roof general information.
3.10.2.7
Roof plates may be stiffened by welded sections, but not connected to girders-rafters.
3.10.4.1
Supported cone roofs slope 3/4" in 12" (or greater).
3.10.4.4
Rafters shall be spaced so that in the outer ring, their centers are not more than 2 ft. (6.28 feet), measured along the circumference. The maximum spacing for inner ring rafters (i.e., "Jack" rafters) is 5.5 feet. NOTE:
3.10.4.5
In earthquake zones, where specified, 3/4" diameter tie rods (or equivalent) shall be placed between the outer ring rafters (i.e., "Long" rafters). Not necessary if "I" or "H" sections are used as rafters.
Roof Columns Structural shapes or steel pipe is acceptable. If pipe, it must be sealed (or provisions for draining or venting made).
3.10.4.6
Rafter and Column Base Clips a. b. c.
Outer row rafter clips - welded to tank shell. Column-base clip guides - welded to tank bottom to prevent lateral shift. Other structural attachments - welded, bolted or riveted.
ITAC API 650 Summary, 2007
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3.11
Wind Load on Tanks (Overturning Stability) 3.11.1 Where specified, overturn stability values are and the wind load (or pressure) shall be assumed to be: a. b. c.
Vertical plane surfaces - 30 lbs. per sq. foot. Projected areas - Cylindrical surfaces - 18 lbs. Conical-double curved surfaces - 15 lbs.
NOTE:
All based on wind velocity of 100 m.p.h.
3.12.3 Anchor spacing - maximum of 10 feet apart.
SECTION 4 - FABRICATION 4.1
Fabrication (General) 4.1.1.2
When material requires straightening: a. b.
Pressing or non-injurious method required (prior to any layout or shaping). Heating or hammering not permitted, unless heated to a forging temperature.
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SECTION 5 - ERECTION 5.1
5.2
Erection (General) 5.1.1
Subgrade shall be uniform and level (unless otherwise specified) i.e., sloped (1 way) bottoms.
5.1.5
Erection lugs shall be removed, noticeable projections or weld metal removed, torn or gouge areas repaired.
Welding (General) 5.2.1.1
Acceptable weld processes a. b. c. d. e. f.
Shielded metal-arc Gas metal-arc Flux-cored arc Submerged-arc Electroslag Electrogas
May be performed manually, automatically or semiautomatically. Complete fusion with base metal required. NOTE: 5.2.1.2
Procedures described in ASME Section IX.
Welding prohibited when: a. b. c. d.
Surfaces are wet or moisture falling on surfaces. During high winds (unless shielded). When base metal temperature is less than 0° F. See Table 5-1 for minimum preheat temperatures.
5.2.1.3
Multilayer welds require slag and other deposit removal before next layer applied.
5.2.1.4
All weld edges must merge with plate surface without a sharp angle. a. b.
5.2.1.8
Maximum acceptable undercut - 1/64" (0.016") vertical butt joints. Maximum acceptable undercut - 1/32" (0.031") horizontal butt joints.
Tack welds, used in vertical joints, shall be removed and not remain in finished joint - when manually welded. If sound, cleaned and fused, tack welds can remain when the submerged-arc process is used.
ITAC API 650 Summary, 2007
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5.2.2
5.2.3
5.2.1.10
Low-hydrogen electrodes shall be used for manual metal-arc welds, including shell to bottom junction for all shell courses over 0.5" thick of Group I-III material.
5.2.1.11
Stud welding is recognized.
Bottoms 5.2.2.2
After layout/tacking, weld out may proceed with some shrinkage seams left open.
5.2.2.3
Shell to bottom welding shall be practically completed, before shrinkage openings (in 5.2.2.2. above) are welded.
Shells 5.2.3.1
Misalignment in completed vertical joints over 5/8" thick, shall not exceed 10% of plate "t", with a maximum of 0.125". Misalignment in completed vertical joints 5/8" thick and less thick shall not be greater than 0.06".
5.2.3.3
The reverse side of double-welded joints (prior to the application of the first bead to the second side), must be cleaned by chipping, grinding or melting out.
5.2.3.4
Joints exceeding 1 1/2" base metal "t" No pass over 3/4" thick is permitted.
5.2.3.5
Requirement for a procedure that minimizes the potential for underbead cracking, in group IV through VI material.
5.2.3.6
After any stress relief (but before hydro), welds attaching nozzles, manways and cleanout openings shall be visually and magnetic particle or die penetrant tested.
5.2.4.1
Shell-to-bottom welds, inside, may be checked by visual and any of the following: magnetic particle, PT solvent, PT water washable, diesel test or right angle vacuum box.
5.2.4.2
New paragraph, a new procedure as an alternative to paragraph 5.2.4.1, allows for pressure testing the volume between the inside and outside welds to 15 psi and applying a soap solution to the face of the fillet welds.
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5.3
INSPECTION, TESTING, AND REPAIRS 5.3.2.1 Butt welds, must be inspected visually, radiographic or ultrasonic method. 5.3.3
Examination and testing of the tank bottom: a. b. c.
Vacuum box Tracer gas test External "float" test
NOTE: Vacuum text procedure removed from this paragraph. The procedure is now in paragraph 6.6, as well as a procedure for tracer gas testing.
5.4
5.3.4
Reinforcing. pads tested by up to 15 PSIG pneumatic pressure between tank shell and reinforcement on each opening.
5.3.5
Shell Testing - Be familiar with procedure.
Weld Repair 5.4.2 Pinhole or porosity bottom leaks - weld over. 5.4.3 All defects in shell or shell-to-bottom joints. NOTE:
5.5
See Specifics - 6.1.7.
Dimensional Tolerances The maximum out-of-plumbness of the top (relative to bottom of shell) may not exceed 1/200 of the total tank height. 5.5.2
The 1/200 criteria shall also apply to fixed roof columns.
5.5.4a Weld "peaking" - shall not exceed 1/2". 5.5.4b Weld "banding" - shall not exceed 1/2". 5.5.5
Foundations (General) 5.5.5.2a
For concrete ring walls - Top shall be level within ± 1/8" in any 30 foot circumference. and within ± 1/4" in the total circumference (measured from average elevation). NOTE:
5.5.5.3
Non-concrete ring walls the values change to ± 1/8" in any 10 feet and ± 1/2" in total circumference.
Sloped foundations - Same criteria. ITAC API 650 Summary, 2007
Page 2-12
SECTION 6 - METHODS OF INSPECTING JOINTS 6.1
Radiographic (Number-Location) 6.1.2.2
Requirements for vertical shell welds a.
Butt-weld joints with the thinner plate 3/8" or less: One spot in the first 10 feet of each type and thickness welded by each welder or operator. Thereafter, one additional spot in each additional 100 feet. NOTE:
b.
Plates greater than 3/8" and through 1" thickness same as thinner plate above plus all junctions. Additionally, two spots in all bottom ring verticals (one as near to bottom as practical, the other random).
c.
Plates thicker than 1" - full radiography of all verticals, plus all junctions. Butt weld around periphery of insert nozzles and manways complete radiography.
d. 6.1.2.3
At least 25% of spots must be at junctions of verticals and roundseam joints - minimum 2 per tank. Additionally, one random spot in each bottom ring vertical.
Requirements for horizontal shell welds One spot in the first 10 feet (same type) thickness without regard to welder or operator. Thereafter, one spot in each additional 200 feet.
6.1.2.4
Multi-tank erection (at same location) may use aggregate footage values of same type and thickness. NOTE: See Fig. 6-1 Radiographic Layout.
6.1.2.8
Each radiograph must clearly show 6" minimum weld length. NOTE: Each film must show Identifier, plus "t" gauge or IQI (penetrometer).
ITAC API 650 Summary, 2007
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6.1.2.9
Tank bottom annular ring (See 3.5.1), the radial joints shall be radiographed as follows: a. b.
Double-butt-weld joints - one spot on 10% of radial joints. Single weld joints with back-up bar - one spot on 50%. of radial joints.
NOTE: 6.1.3
6.1.6
Technique - Radiography 6.1.3.1
ASME method, Section V NDE, Article 2.
6.1.3.2
Radiographers meet ASNT - SNT - TC - 1A requirements.
6.1.5
Radiography Standards - Acceptability to be in accordance with Section VIII, Div. 1, Par. UW-51(B), ASME.
Unacceptable radiographs (under 6.1.5), or the limits of the deficient radiograph are not defined, 2 adjacent shots are required. NOTE:
6.1.7
6.2.1 6.3
Preferable spot - at the outer edge, near shell.
If adjacent spots are still unacceptable, additional spots are examined until weld is acceptable.
Weld defects shall be repaired by chipping or melting out from one or both sides, and rewelded. 6.1.7.2
When all welds are repaired, repeat original inspection procedure.
6.1.8.1
The manufacturer shall prepare an as-built radiograph map showing the location of all radiographs taken along with the film identification marks.
Magnetic Particle - ASME Section V, Article 7.
Ultrasonic Examination 6.3.1
Ultrasonic Method in lieu of radiography see Appendix U.
6.3.2
UT not in lieu of radiography - ASME Section V, Article 5 6.3.2.4
Must be ASNT-SNT-TC-1A requirements
6.3.2.5
Acceptance standards shall be agreed upon by the purchaser and the manufacturer.
ITAC API 650 Summary, 2007
Page 2-14
6.4
Liquid Penetrant Examination 6.4.1
ASME Section V, Article 6 must be followed.
6.4.2
Must have written procedure
6.4.3
Manufacturer determines qualifications
6.4.4
Acceptance standards, ASME Section VIII, Appendix 8, paragraphs 8-3, 8-4 and 8-5.
6.5.1
Visual acceptability based on following: a. b.
No visible crater or surface cracks or arc strikes. Undercut does not exceed limits given in 5.2.1.4 for vertical and horizontal butt joints. NOTE:
c.
1/64" maximum allowable undercut on attached nozzles, manways, cleanout openings and permanent attachments.
Frequency of surface porosity does not exceed one "cluster" in any 4" of length and the diameter of each cluster does not exceed 3/32" (0.094”).
6.5.2
All welds failing to meet 6.5.1 requirements must be reworked prior to hydro-testing.
6.6
Vacuum Testing Vacuum testing and tracer gas testing procedures are listed. SECTION 7 - WELDING PROCEDURE/QUALIFICATIONS
* No specifics SECTION 8 - MARKING (NAMEPLATE) * No specifics
ITAC API 650 Summary, 2007
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API - 650 (APPENDIX REVIEW) Appendix. A - Optional Design Basis For Small Tanks (Do not use Appendix A on the API 653 Exam). A.1.4 The overturning effect of wind load should be considered. A.1.5 Consider Tables A-1 through A-4 for sizes, capacities, shell plate thickness, etc. A.2.1 Shell plate thickness limited to 1/2". A.5.1 Vertical and horizontal joints, bottom, shell-to-bottom, roof and top angle - same provisions as normal size. A.5.2 Normal weld spacing restrictions are relaxed. A.5.3 Radiograph inspection - slightly relaxed. Appendix B - Foundation Construction B.2.1 Requires soil coring to determine sub-surface conditions. B.2.3 Varying conditions that require special engineering considerations a. b. c. d. e. f.
Sites on hillsides. Sites on swampy or filled ground. Sites underlain by layers of plastic clay. Sites adjacent to water courses or deep excavations. Sites immediately adjacent to heavy structures. Sites exposed to floodwaters.
B.2.4 General methods to improve non-acceptable subsoil a. b. c. d. e. f.
Removal and replacement with suitable, compacted subsoil. Compacting with short piles - preloading with an overburden of suitably drained earth. Removing water content then compacting. Stabilizing by chemical methods or grout injection. Driving bearing piles/foundation piers. Load distribution over a extra large area.
B.2.5 Fill material must be sound and durable (i.e., at least equivalent to fill used in good highway construction), free from vegetation, organic matter or other corrosive substances.
ITAC API 650 Summary, 2007
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B.3.1 Suggested grade/surface elevation - 1'. B.3.2
Finished grade (i.e., surface next to bottom) a. b. c.
Top 3"-4" - Clean sand, gravel, crushed stone (maximum size 1"), or other suitable inert material. Equipment and material movement will cause damages. Correct before bottom plates are installed. Oiled/stabilized finished grade.
B.3.3 Finished tank grade Crowned from outer edge to center - 1" in 10'. B.4.2.1
Concrete foundation ringwall advantages a. b. c. d. e.
Better distribution of concentrated load. Provides a level, solid starting plane for erection. Provides better means to level tank during erection. Retains subsoil fill and finished top surface. Minimizes moisture under tank bottom.
Fig. B-1 - Foundation with Concrete Ringwall. Fig. B-2 - Foundation with Crushed Stone Ringwall. NOTE:
Have familiarity with above types.
B.4.3 Earth Foundations (without concrete ringwall) a. b. c. e.
A 3' shoulder and berm - protected from weathering. Smooth, level surface for bottom plates. Adequate drainage. Surface true to specified plane (tolerances specified in 5.5.6).
ITAC API 650 Summary, 2007
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Appendix C - External Floating Roofs C.3.1 General If a windskirt or top-shell extension is used for the purpose of containing roof seal at its highest point of travel, appropriate alarm devices are required. C.3.2 Joints Same as required in 3.1 (i.e., single lap, full fillet, 1" minimum lap, etc.). C.3.3. On the bottom side, where flexure is anticipated adjacent to girders, support legs, or other relatively rigid members, full-fillet welds (not less than 2" long on 10" centers) shall be used on any plate laps that occur within 12" of any such member. C.3.3.4
Decks (double and diaphragm) designed for drainage, shall have a minimum slope of 3/16" in 12".
C.3.4. Pontoon roofs shall have sufficient buoyancy to remain afloat on a specific gravity product of 0.7 and with primary drains inoperative for following conditions: a. b.
A 10" of rainfall in a 24 hour period with roof intact, except for double deck floating roofs that have emergency drains. Single-deck (i.e., diaphragm) and any 2 adjacent compartments punctured in single-deck pontoon types and any 2 adjacent compartments punctured in double-deck roofs Both types with no water or live load.
C.3.5 Pontoon Openings a. b. c.
Each compartment provided with liquid tight manway. Manway covers provided with suitable hold-down fixture. Compartments vented against internal/external pressure.
C.3.8 Roof Drains a. b. c. d.
Primary drains may be hose, jointed or siphon type. Check valve required (hose and jointed pipe type) on pontoon and pan type roofs. Hose drain types designed to permit replacement without personnel entering the tank (* Not Normal). Minimum roof drain size - 3" for a tank 120 in diameter and less; 4" for a tank greater than 120 feet in diameter.
ITAC API 650 Summary, 2007
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C.3.9 Vents Purchaser furnishes fill and withdrawal flow rates. Fabricator sizes accordingly. C.3.10.1 and 3.10.2 Roof support leg requirements a. b. c. d. e.
Pipe legs - notched or perforated at bottom. Adjustable length from roof top side. Designed to support roof and a uniform live load of at least 25 lbs./sq. ft. Sleeves, gussets, etc., required at deck entry points. Load distribution members required on tank bottom.
NOTE: If pads used, continuous weld required. C.3.11 Manways Minimum of 1 with 24" access, with gasket and bolted cover. C.3.12 Centering/anti-rotation devices required. C.3.13 Seals a. b.
The space (rim) between outer roof periphery and shell - sealed by flexible device providing a reasonable close fit to shell surfaces. No plain (i.e., bare) carbon steel shoes allowed. NOTE:
c. d.
Adequate expansion joints (i.e., secondary seal strips) required. Must be durable to environment and must not contaminate the product. NOTE:
C.4
Must be galvanized or coated See API RP 2003.
Aviation fuel restrictions.
Fabrication, Erection, Welding, Inspection And Testing
C.4.2 Deck and other joint seams tested for leaks with vacuum box, penetrating oil, etc. C.4.3 Water flotation test required at initial erection. Weld repair can be seal-weld type. C.4.5 50 PSIG hydro test required on drain system. Appendix D - Technical Inquiries (No specific comments) ITAC API 650 Summary, 2007
Page 2-19
Appendix E - Seismic Design of Storage Tanks This section was totally rewritten, but does not appear on the API 653 Exam. Appendix F - Design of Tanks for Small Internal Pressures F.1.3 Internal pressures that exceed the weight of the shell, roof and framing but do not exceed 2 1/2 pounds per square inch gauge when the shell is anchored to a counterbalancing weight, such as a concrete ringwall. Appendix G - Structurally Supported Aluminum Dome Roofs (No specific comments) Appendix H - Internal Floating Roofs H.1
Scope Subsection 3.10 of standard. is applicable except as modified in this appendix. H.2.2 Types a. b. c. d. e. f. g.
H.3
Metallic pan internal - liquid contact with two peripheral rims. Metallic open top bulkhead - liquid contact/peripheral rim and open top bulkheads. Metallic pontoon - liquid contact/closed pontoons. Metallic double deck. Metallic on floats - deck above liquid. Metallic sandwich-panel - liquid contact, surface-coated honeycomb panels. Hybrid internal floating roofs.
Materials H.3.2 Steel H.3.3 Aluminum H.3.4 Stainless Steel Same general provisions as for open top floating roofs.
ITAC API 650 Summary, 2007
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H.3.5.2/3.5.7 - Seal types a. b. c. d. e. H.4
Flexible foam contained in an envelope Liquid fill (in an envelope) Wiper type (resilient) Metallic Shoe Other mutually agreeable types (fabrication and customer)
General Requirements and Design H.4.4 Peripheral Seals H.4.5.1 through 4.5.3 - Design Features a. b. c. d.
Accommodate ± 4" local deviation between roof and shell. Tank shell free of internal projections, burrs, etc. Envelope seals to be liquid tight. Field joints, minimum 3" lap. Mechanical shoe types - Galvanized steel (16 ga.) - Stainless Steel (18 ga).
H.4.5 Roof Penetrations Columns, ladders and other rigid vertical appurtenances that penetrate the deck shall have a seal permitting a local deviation of ± 5". NOTE:
Appurtenances require a vertical plumbness of 3".
H.4.6 Roof Supports H.4.6.1 through H.4.6.8 - Specific requirements a. b. c. d.
Both fixed and adjustable supports are acceptable. Supports/attachments designed to support a uniform live load of 12.5 lbs./sq. ft., unless roof is equipped with drains to prevent liquid accumulation. Same underside tack-weld required on seams as on conventional floating roofs. (See C.3.3.3.). Same requirements on notching pipe legs, welding support pads to bottom, etc., as on conventional. NOTE:
Pads may be omitted with purchaser approval.
ITAC API 650 Summary, 2007
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H.5
Openings and Appurtenances H.5.1 Ladder Specifics H.5.2 Vents H.5.2.2
Circulation Vents a. b. c.
H.5.2.2.2
Located on shell or fixed roof (above seal in full tank). Maximum spacing - 32". No fewer than 4 total. Sized equal to or greater than 0.2 sq. ft. per ft. of tank diameter. Covered with corrosion resistant screen and weathershield.
Open vent required at center of fixed roof minimum area of 50 sq. in.
NOTE:
Pressure-vacuum vents (rather than air openings) required on gas blanketed tanks.
H.5.3 Overflow Slots H.5.4 Antirotation Devices H.5.5 Manholes and Inspection Hatches H.6
Fabrication, Erection, Welding, Inspection and Testing
Appendix I - Undertank Leak Detection and Subgrade Protection (No specific comments) Refer to API RP 652 and 651 for more guidelines. Appendix J - Shop Assembled Storage Tanks (No specific comments) Appendix K - Engineering Data (No specific comments) Appendix L - Data Sheets (No specific comments) In the real world use these sheets as a guide only.
ITAC API 650 Summary, 2007
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Appendix M - Requirements for Tanks Operating at Elevated Temperatures (No specific comments) Appendix N - Use of New Materials That are Not Identified (No specific comments) Appendix O - Recommendations for Under-Bottom Connections (No specific comments) Appendix P - Allowable External Loads on Tank Shell Openings (No specific comments) Appendix R – Load Combinations (No specific comments) Appendix S - Austenitic Stainless Steel Storage Tanks S.1.1 This section covers tank construction of material grades 304, 304L, 316, 316L, 317, and 317L. S.1.2 Ambient temperature tanks shall have a design temperature of 1000 F Appendix T - NDE Requirements Summary Appendix U - Ultrasonic Examination in Lieu of Radiography (No specific comments) Appendix V – Design of Storage Tanks for External Pressure (This is a new section. No specific comments)
ITAC API 650 Summary, 2007
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Visit our website www.itac.net NAME:
DATE:
The first part of the exam is "Open Book.”
API 650 Tenth Ed. CODE QUIZ (Select The Best Answer)
1.
A peripheral seal, on an internal floating roof, shall be designed to accommodate _____ of local deviation between the floating roof and the shell. a. b. c. d.
2.
Welders who weld vertical butt welds on API 650 tanks shall be qualified in accordance with . a. b. c. d.
3.
API 1104 ASME Section V ASME Section IX AWS D1.1
A new tank will hold a product with the specific gravity of 1.05. The corrosion allowance is .10. The thickness of the first course is 1.25 inches; The hydrostatic test stress is 25,000 PSI. What is the thickness required for the annular plate? (Note: Include corrosion allowance). a. b. c. d.
4.
the manufacturer's standard + 100 mm + 1/8 inch the inspector's experience
5/16" 11/16" 3/8" 7/16"
In order to comply with API 650, the finished surface of a weld reinforcement on plate 1/2" thick, horizontal butt joints, may have a reasonably uniform crown not to exceed ________, for radiographic examination. a. b. c. d.
1/4" 3/16" 1/8" 1/16" ITAC API 650 Summary, 2007
Page 2-24
ITAC 5.
What is the design thickness for the first course of a new tank 60 tall, with a fill height of 58 and a diameter of 804”? The material of construction is A516M 485. Specific gravity of .6 a. b. c. d.
6.
What is the hydrostatic test shell thickness of the tank in question 5? a. b. c. d.
7.
.281” .416” .500” 1.00”
If the first course of a new tank is 12.5 mm and the design metal temperature is -7oC, what is the material group? a. b. c. d.
9.
.416 .281 .117 .500
To what thickness should the tank in question 6 be constructed? a. b. c. d.
8.
.097 .416 28.1 .281
Group I Group II Group III Group IV
What is the maximum reinforcement on a vertical butt joint, if the plate is .625 in. thick? a. b. c. d.
3/32” 1/8” 3/16” 1/4”
ITAC API 650 Summary, 2007
Page 2-25
ITAC API 650 Summary, 2007
Page 2-26
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Please close all materials. The remainder of the Quiz is “Closed Book.”
ITAC API 650 Summary, 2007
Page 2-27
ITAC API 650 Summary, 2007
Page 2-28
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The second part of the quiz is "Closed Book." 10.
According to API 650, which of the following types of connections shall be stress relieved? a. b. c. d.
11.
Upon completion, the roof of a tank designed to be gas tight shall be tested by which one of the following methods? a. b. c. d.
12.
erection/fabrication manufacturer purchaser Nuclear Regulatory Commission certified inspector
Per API 650, external floating roof deck plates having support leg or other rigid penetrations closer than ____ inches to lap weld seams must be full fillet welded not less than 2 inches on 10 inch centers. a. b. c. d.
14.
Magnetic particle testing of all welds Application of internal air pressure not exceeding the weight of the roof plates and applying a solution suitable for the detection of leaks Penetrant testing the weld joints Visual inspection of the weld joints
Each welder making welds on a tank shall be certified by the _______. a. b. c. d.
13.
All nozzles All Group I, II, III or IIIA opening connections less than 12 inches All Group IV, IVA, V or VI opening connections requiring reinforcement All connections requiring reinforcement
6 12 14 18
Upon completion of welding of the new tank bottom, the welds shall be inspected by which one of the following methods? a. b. c. d.
Radiographs Vacuum or tracer gas Penetrant testing Hammer testing
ITAC API 650 Summary, 2007
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ITAC 15.
The maximum reinforcement thickness for vertical butt joints, less than or equal to 1/2" thick is . a. b. c. d.
16.
Annular bottom plates shall have a radial width that provides at least _____ inches between the inside of the shell and any lap-welded joint in the remainder of the bottom. a. b. c. d.
17.
c. d.
a joint between two abutting parts lying in approximately the same plane a joint between two abutting parts lying in approximately the same plane that is welded from both sides a joint between two overlapping members in which the overlapping edges of both members are welded with fillet welds a fillet weld whose size is equal to the thickness of the thinner joined member
Openings in tank shells larger than required to accommodate an NPS _____ inch flanged or threaded nozzle shall be reinforced. a. b. c. d.
20.
3/32 1/8 1/64 3/64
A double-welded butt weld is ______. a. b.
19.
10 30 24 18
The maximum acceptable undercutting of the base metal for vertical butt joints is ___ inch. a. b. c. d.
18.
1/16" 1/8" 3/32" 3/16"
one two three four
The acceptability of welds examined by radiography shall be judged by the standards in . a. b. c. d.
ASME Section V, Division 7 ASME Section IX, Paragraph QW-191 ASME Section VIII, Division 1, Paragraph UW-51(b) API 1104 ITAC API 650 Summary, 2007
Page 2-30
ITAC 21.
When bottom annular plates are required by paragraph 3.5.1 of API 650, the radial joints shall be radiographed. For single welded butt joints using a backup bar, one spot radiograph shall be taken on _____ percent of the radial joints. a. b. c. d.
22.
Annular bottom plates must extend a minimum of _______ inches outside the tank shell. a. b. c. d.
23.
Manufacturer Purchaser State Inspector API 653 Inspector
A new tank is under construction. How many radiographs are required on the first course vertical welds if the shell is 35 mm thick? a. b. c. d.
26.
500° F 500° C 200° F 200° C
Who is responsible for compliance with the API 650 standards? a. b. c. d.
25.
1 1/2 2 3 4
The maximum operating temperature for tanks constructed to API 650 (not including appendices) is _______. a. b. c. d.
24.
10 30 50 100
One radiograph shall be taken in every vertical joint 100% of the vertical joint Two radiographs shall be taken in the vertical joint No radiographs required
All bottom plates shall have a minimum nominal thickness of _____ inch, exclusive of any corrosion allowance specified by the purchaser for the bottom plates. a. b. c. d.
3/8 .250 .516 .325 ITAC API 650 Summary, 2007
Page 2-31
ITAC 27.
Repairs of defects shall not be attempted on a tank that is filled with _____ or on a tank that has contained ____ until the tank has been emptied, cleaned and gas freed in a safe manner. a. b. c. d.
28.
Misalignment in completed vertical joints over 5/8" shall not exceed what percentage of the plate thickness? a. b. c. d.
29.
ASME Section VIII ASME Section V ASME Section XI Agreed upon by the purchaser and the manufacturer
Column-based clip-guides shall be welded to the tank bottom to prevent __________. a. b. c. d.
32.
diesel air stress gas
Ultrasonic acceptance standards, in accordance with API 650, shall be ______. a. b. c. d.
31.
25% with a maximum of 1/16" 2% with a maximum of 3/64" 5% with a maximum of 3/8" 10% with a maximum of 1/8"
Reinforcing plates of shell penetrations shall be given a(n) ________ test, in accordance with API Standard 650. a. b. c. d.
30.
nitrogen oil water grain
internal erosion structural uplifting lateral movement of column bases lateral expansion and contraction
Who is responsible for specifying whether the dimensions of a tank will be given in SI units or US customary units? a. b. c. d.
Industrial requirements U.S. Government mandates The purchaser The manufacturer ITAC API 650 Summary, 2007
Page 2-32
ITAC 33.
When performing a vacuum test, the gauge should register a partial vacuum of at least ? a. b. c. d.
34.
When reviewing a radiograph of an intersection, 2 inches of weld length must be shown on each side of the vertical intersection. How much of the vertical weld must be shown? a. b. c. d.
35.
.
1” 1 1/2” 1 3/4” 2”
Which electrodes are in the AWS A5.1 specification? a. b. c. d.
38.
.
the purchaser specifies the requirement. API mandates the requirement the manufacturer approves the requirement required by jurisdictional requirements
Shell plates are limited to a maximum thickness of a. b. c. d.
37.
2 inches 50 mm 3 inches No API 653 requirement
An appendix becomes a requirement only when a. b. c. d.
36.
2 lbf/in.2 3 lbf/in.2 4 lbf/in.2 5 lbf/in.2
E-9018 E-8518 E-8018 E-6010
What is the minimum size fillet weld that can be installed on a new tank? a. b. c. d.
1/8” 3/16” 1/4” 5/16”
ITAC API 650 Summary, 2007
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ITAC 39.
Roof plates shall have a minimum nominal thickness, in addition to any required corrosion allowance, of . a. b. c. d
40.
The slope of a supported cone roof shall be at least a. b. c. d.
41.
10% 15% 20% 25% .
the floor only the roof only shell welds greater than 1/2” shell welds less than 1/2”
Which of the following NDE methods is not acceptable for the inspection of new shell-to-bottom welds. a. b. c. d.
44.
1 m in 6 m 19 mm in 300 mm .75 km in 12 km 7.5 mm in 1.2 mm
Low hydrogen electrodes shall be used for weld on a. b. c. d.
43.
.
Misalignment in completed vertical joints for plates greater than 5/8” thick shall not exceed . a. b. c. d.
42.
3/16” 1/4” 7-Gauge both a and c
Magnetic particle Liquid Penetrant Vacuum Box Radiography
A tank construction crew is using a vacuum box constructed of clear plastic and a sponge-rubber gasket. a. b. c. d.
This is an acceptable practice. This is a good vacuum test. This vacuum box is not recognized by API 650. The crew can use any style vacuum box.
ITAC API 650 Summary, 2007
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ITAC 45.
Floor plates may be tested by vacuum box testing or a. b. c. d.
46.
1/4” 1/2” 3/4” 1”
the contractor API 1104 ASME Section IX ASME Section VIII
A joint between two members that intersect at an angle between 0o (a butt joint) and 90o (a corner joint) is called a(n) . a. b. c. d.
50.
.
Welds examined by radiography shall be judged as acceptable or unacceptable by . a. b. c. d.
49.
6.5” 5.4” 3.9” 2.0”
Banding at horizontal weld joints shall not exceed a. b. c. d
48.
air pressure test tracer gas and compatible detector explosion-bulge test acoustic emission test
What is the maximum out-of-plumbness of the top of the shell relative to the bottom of the shell of a new tank that is 65 tall? a. b. c. d.
47.
.
fillet joint butt joint angle joint joint that requires backing
The client has requested the top course of a tank to be 1/2” thick. The maximum thickness of all the other courses is 3/8” thick. a. b. c. d.
The client wants it, do it. The top course is usually 1/2” thick. No shell course shall be thinner than the course above it. The thickness of each course is based on the design thickness of the tank not including corrosion allowance.
ITAC API 650 Summary, 2007
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API 650 Tenth Ed. CODE QUIZ Answer Key 1. b 2. c 3. c 4. d 5. d Solution:
(Page H-4, Par. H.4.4.3) API 650 (Page 7-2, Par. 7.3.2) API 650 (Page 3-6, Par. 3.5.3) API 650 (Page 6-3, Par. 6.1.3.4) API 650 (Page 3-9, Par. 3.6.3.2) API 650 td = 2.6D(H-1)G + CA Sd td = 2.6(80)(58-1)(.6) 25,300 td = 7113.6 25,300
6. a Solution:
td = .281 (Page 3-9, Par. 3.6.3.2) API 650 tt = 2.6D(H-1) St tt = 2.6 (80) 58 - 1 28,500 tt = 11,856 28,500
7. 8. 9. 10. 11. 12. 13. 14. 15. 16. 17.
b a b c b a b b c c c
tt = .416 (Page 3-6, Par. 3.6.1.1) API 650 (Page 2-2, Fig. 2-1) API 650 (Page 5-1, Par. 5.2.1.5) API 650 (Page 3-19, Par. 3.7.4.3) API 650 (Page 5-4, Par. 5.3.6.1) API 650 (Page 7-2, Par. 7.3.1) API 650 (Page C-1, Par. C.3.3.3) API 650 (Page 5-4, Par. 5.3.3) API 650 (Page 5-1, Par. 5.2.1.5) API 650 (Page 3-6, Par. 3.5.2) API 650 (Page 5-1, Par. 5.2.1.4) API 650 ITAC API 650 Summary, 2007
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ITAC 18. 19. 20. 21. 22. 23. 24. 25. 26. 27. 28. 29. 30. 31. 32. 33. 34. 35. 36. 37. 38. 39. 40. 41. 42. 43. 44. 45. 46. 47. 48. 49. 50.
b b c c b c a b b b d b d c c b c a c d b d b a c d a b c b d c c
(Page 3-1, Par. 3.1.1.1) API 650 (Page 3-13, Par. 3.7.2.1) API 650 (Page 6-3, Par. 6.1.5) API 650 (Page 6-3, Par. 6.1.2.9b) API 650 (Page 3-6, Par. 3.5.2) API 650 (Page 1-1, Par. 1.1.1) API 650 (Page 1-3, Par. 1.3) API 650 (Page 6-1, Par. 6.1.2.2c) API 650 (Page 3-6, Par. 3.4.1) API 650 (Page 5-5, Par. 5.4.4) API 650 (Page 5-2, Par. 5.2.3.1) API 650 (Page 5-4, Par. 5.3.4) API 650 (Page 6-4, Par. 6.3.2.5) API 650 (Page 3-50, Par. 3.10.4.6) API 650 (Page 1-1, Par. 1.1.3) API 650 (Page 6-5, Par. 6.6.3) API 650 (Page 6-1, Par. 6.1.2.2b) API 650 (Page 1-1, Par. 1.1.4) API 650 (Page 2-1, Par. 2.2.1.4) API 650 (Page 2-10, Par. 2.8.1) API 650 (Page 3-1, Par. 3.1.3.3) API 650 (Page 3-36, Par. 3.10.2.2) API 650 (Page 3-48, Par. 3.10.4.1) API 650 (Page 5-2, Par. 5.2.3.1) API 650 (Page 5-2, Par. 5.2.1.10) API 650 (Page 5-2, Par. 5.2.4.1) API 650 (Page 6-5, Par. 6.6.1) API 650 (Page 5-4, Par. 5.3.3) API 650 (Page 5-5, Par. 5.5.2) API 650 (Page 5-5, Par. 5.5.4(b) API 650 (Page 6-3, Par. 6.1.5) API 650 (Page 7-1, Par. 7.1.1) API 650 (Page 3-7, Par. 3.6.1.5) API 650
ITAC API 650 Summary, 2007
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ITAC API 650 Summary, 2007
Page 2-38
Section 3 575 Summary–07
API RECOMMENDED PRACTICE 575 GUIDELINES AND METHODS FOR INSPECTION OF ATMOSPHERIC AND LOW-PRESSURE STORAGE TANKS Second Edition, May, 2005 SECTION 1 - SCOPE Atmospheric and low-pressure storage tanks, constructed to API 12A, 12C, 620 and 650, that have been in service. SECTION 3 - DEFINITIONS For the purposes of this recommended practice, the following definitions apply: 3.1 alteration: Any work on a tank involving cutting, burning, welding, or heating operations that changes the physical dimensions and/or configuration of a tank. Examples of alterations include: a. The addition of a manway or nozzle exceeding 12 in. NPS (nominal pipe size). b. An increase or decrease in tank shell height. 3.2 applicable standard: The original standard of construction, such as API standards or specifications or Underwriter Laboratories (UL) standards, unless the original standard of construction haws been superseded or withdrawn from publication; in this event, applicable standard means the current edition of the appropriate standard. See API Std 653, Appendix A for background on editions of API welded storage tank standards. 3.3 atmospheric pressure: When referring to (vertical tanks, the term “atmospheric pressure” usually means tanks designed to API Std 650, although API Std 620 uses the term atmospheric pressure to describe tanks designed to withstand an internal pressure not
exceeding the weight of the roof plates. API Std 650 also provides for rules to design tanks for “higher internal pressure” up to 2 1/2 lbf/in.2 (18 kPa). API Std 653 uses the generic meaning for atmospheric pressure to describe tanks designed to withstand an internal pressure up to, but not exceeding 2 1/2 lbf/in. 2 (18 kPa) gauge. 3.4 authorized inspection agency: The inspection organization having jurisdiction for a given aboveground storage tank. It can be one of the following: a. The inspection organization of an insurance company which is licensed or registered to and does write aboveground storage tank insurance. b. An owner or operator of one or more aboveground storage tank(s) who maintains an inspection organization for activities relating only to his equipment and not for aboveground storage tanks intended for sale or resale.
ITAC API RP 575 Summary, 2007 Page 3-1
c. An independent organization or individual under contract to and under the direction of an owner or operator and recognized or otherwise not prohibited by the jurisdiction in which the aboveground storage tank is operated. The owner or operator’s inspection program shall provide the controls necessary for use by authorized inspectors contracted to inspect aboveground storage tanks. 3.5 authorized inspector: An employee of an authorized inspection agency that is certified as an aboveground storage tank inspector per API Std 653, Appendix D. 3.6 bottom-side: The exterior surface of the bank bottom, usually used when describing corrosion. Other terms with the same meaning are “under-side” or “soil-side.” 3.7 change-in-service: A change from previous operating conditions involving different properties of the stored product such as specific gravity or corrosivity and/or different service conditions of temperature and/or pressure. 3.8 examiner: A person who assists the API authorized tank inspector by performing specific non-destructive examination (NDE) on the tank but does not evaluate the results of those examinations in accordance with API Std 653 or this recommended practice, unless specifically trained and authorized to do so by the owner or user. The examiner does not need to be certified in accordance with API Std 653 nor needs to be an
employee of the owner or user, but shall be trained and competent in the applicable procedures in which the examiner is involved. In some cases, the examiner may be required to hold other certifications as necessary to satisfy owner or user requirements. Examples of other certification that may be required are American Society for NonDestructive Testing SNT-TC-1A or CP189, or American Welding Society Welding Inspector Certification. The examiner’s employer shall maintain certification records of the examiners employed, including dates and results of personnel qualifications and shall make them available to the API Authorized Inspector. 3.9 inspector: An Authorized Inspector and an employee of an Authorized Inspection Agency who is qualified and certified to perform tank inspections under this standard. 3.10 MFL (magnetic flux leakage): An electromagnetic scanning technology for tank bottoms. Also known as MFE (magnetic flux exclusion). 3.11 product-side: the interior surface of a tank bottom, usually used when describing corrosion. Other terms with the same meaning are “top-side” or product-side.” 3.12 owner/operator: The legal entity having control of and/or responsibility for the operation and maintenance of an existing storage tank.
ITAC API RP 575 Summary, 2007 Page 3-2
3.13 reconstruction: The work necessary to reassemble a tank that has been dismantled and relocated to a new site.
3.16 shell capacity: The capacity hat the tank can hold based on the design liquid level (see API Std 650).
3.14 reconstruction organization: The organization having assigned responsibility by the owner/operator to design and/or reconstruct a tank.
3.17 soil-side: See definition for bottom-side.
3.15 repair: Any work necessary to maintain or restore a tank to a condition suitable for safe operation. Typical examples of repairs includes: a. Removal and replacement of material (such as roof, shell, or bottom material, including weld metal) to maintain tank integrity. b. Re-leveling and/or jacking of a tank shell, bottom, or roof. c. Addition of reinforcing plates to existing shell penetrations. d. Repair of flaws, such as tears or gouges, by grinding and/or gouging followed by welding.
3.18 storage tank engineer: One or more persons or organizations acceptable to the owner or user who are knowledgeable and experienced in the engineering disciplines associated with evaluating mechanical and material characteristics affecting the integrity and reliability of tank components and systems. The tank engineering, by consulting with appropriate specialists, should be regarded as a composite of all entities necessary to properly address technical requirements and engineering evaluations. 3.19 tank specialist: Someone experienced in the design and construction of tanks per API Std 620 and/or PI Std 650, and the inspection and repair of tanks per API Std 653. 3.20 top-side: See definition for product-side.
ITAC API RP 575 Summary, 2007 Page 3-3
SECTION 4 - TYPES OF STORAGE TANKS 4.1
General Storage tanks are used in a wide variety of industries for a wide range of products. Basically, our discussion will deal primarily with those that store crude oil, intermediate and finished products, chemicals, water and a general assortment of other products. For our purposes, the inspection, evaluation and comments dealing with future service conditions and limitations can all be generally categorized together, since conditions that would change the serviceability or repair needs for a tank are basically identical, regardless of the product stored. Other than diameter and height, the only other two (2) service factors to be considered are the specific gravity and temperature of the product.
4.2
4.1.1
Linings, as covered in API RP 652.
4.1.2
Cathodic protection in API RP 651.
4.1.3
Leak detection systems, see API 650.
Atmospheric Storage Tanks Those that have been designed to operate in their gas and vapor spaces at internal pressures which approximate atmospheric pressure. 4.2.2
Use of Tanks Atmospheric storage tanks are used to store materials having a true vapor pressure (at storage temperature) which is substantially less than atmospheric pressure. NOTE:
4.3
Vapor Pressure is the pressure on the surface of the liquid caused by the vapors of the liquid. Vapor pressure varies with temperature, inasmuch as that more of the liquid vaporizes as the temperature rises.
Low-Pressure Storage Tanks 4.3.1
Description and Design of Low-Pressure Storage Tanks Low-pressure storage tanks are those designed to operate at pressures in their gas or vapor spaces exceeding the 2.5 pounds per square inch gauge pressure permissible in API Standard 540, but not exceeding 15 pounds per square inch gauge. Low-pressure tanks are usually built to API Standard 620.
ITAC API RP 575 Summary, 2007 Page 3-4
SECTION 5 - REASONS FOR INSPECTION AND CAUSES OF DETERIORATION 5.1
Reasons for Inspection a.
Reduce the potential for failure and the release of stored products.
b.
Maintain safe operating conditions.
c.
Make repairs or determine when repair or replacement of a tank may be necessary.
d.
Determine whether any deterioration has occurred and, if so, prevent or retard further deterioration.
e.
Keep ground water, nearby waterways and the air free of hydrocarbon and chemical pollution.
f.
Regulatory compliance.
g.
Risk management through data gathering and prioritization of maintenance and capital expenditures.
5.2.1
External Corrosion a.
External (underside) tank bottom corrosion results from contamination in the pad. Cinders contain sulfur compounds that become very corrosive when moistened.
b.
Electrolytic corrosion (pitting type) results when clay, rocks, oyster shell, wooden grade stakes, etc., come in contact with the underside bottom, as they attract and hold moisture.
c.
Poor drainage from faulty pad preparation.
d.
Lower external shell corrosion due to: i. ii. iii.
e. 5.2.2
Settlement, with corrosion at soil grade line Casual water collection point Insulation moisture “wicking”.
Shell appurtenances are subject to crevice corrosion at non-seal welded joints (angles/flats).
Internal Corrosion a.
Primarily dependent on product stored.
b.
Corrosion resistant linings are most common preventative. ITAC API RP 575 Summary, 2007 Page 3-5
c.
Normal locations and causes are: i. ii.
d.
Vapor space (above the liquid). Most commonly caused by H2 S vapor, water vapor, oxygen or a combination of the three. Liquid area. Most commonly caused by acid salts, H2 S or other sulfur compounds.
Other forms of internal attack, considered as forms of corrosion are: i. ii. iii. iv. v.
Electrolytic corrosion. Hydrogen blistering. Caustic Embrittlement. Graphitic corrosion (cast iron parts). Dezincification (brass parts).
In the areas covered by the stored liquid, corrosion is commonly caused by acid salts, hydrogen sulfide or bottom sediment and water (BS&W). 5.3
Deterioration of Other Than Flat Bottom and Non-Steel Tanks a.
Both wooden and concrete tanks may require inspection.
b.
Potential problem areas: i. ii.
5.4
Wood - subject to rotting, attack by termites, subject to shrinkage, corrosion of the steel bands. Concrete - internal corrosion, cracking due to settlement or temperature change, spalling (exposes reinforcement and corrodes due to atmosphere).
c.
Tanks constructed of other materials (i.e., alloy or aluminum) can present special problems, but are subject to the same mechanical damage potential as steel tanks.
d.
Other nonmetallic tanks (i.e., plastic, fiberglass or glass reinforced epoxy) may present special problems, but will not be discussed in this presentation.
Leaks, Cracks and Mechanical Deterioration a.
Leaks, whatever the cause, can cause serious economic losses or environmental damage resulting in fines or penalties by governmental agencies. These, however, pale in comparison to the problems associated with the instantaneous (catastrophic) failure of a shell with resulting loss of the entire tank, the product stored, plus perhaps all surrounding structures. ITAC API RP 575 Summary, 2007 Page 3-6
b.
Plate cracking is always of prime importance when inspecting tanks. Cracks can result from a wide variety of causes. The more frequent causes are: i. ii iii. iv. v.
Faulty welding. Unrelieved stress concentrations (i.e., stress raisers) around fittings or appurtenances. Stress caused by settlement or earth movement, especially differential settlement Vibration Poorly designed repair or “sloppy” craftsmanship.
The most likely points of occurrence are: i. ii. iii iv. v. NOTE:
The lower shell to bottom sketch plate is especially critical in relatively larger or hot tanks. It can act as a plastic hinge with the potential for cracking. See API 650 (Appendix “M”).
c.
Many other kinds of mechanical deterioration can develop. In earthquake areas, sloshing damage may occur to roofs. Shell buckling (directly above bottom) can occur in tanks having relatively large height to diameter ratios.
d.
Another form of mechanical deterioration is settlement. Frequent causes are: i. ii. iii.
5.5
Shell to bottom junction. Around nozzle and manway connections. .Around rivet holes. At welded brackets. At welded seams.
Freezing/thawing of the ground. Unusually high tides in tidal areas. Slow lateral flowing of the soil.
Deterioration and Failure of Auxiliary Equipment a.
Frequent problem areas are associated with pressure/vacuum conservation vents.
ITAC API RP 575 Summary, 2007 Page 3-7
b.
Most common problems are: i. ii. iii. iv. v. vi. vii.
Collection of “gummy” residue on pallets. Moving parts, guide and seat corrosion. Foreign deposits (by birds or insects). Ice formation. Tampering. Adding extra weights to pallets (which changes release point of vapor). Lay-down of sand from abrasive blasting.
NOTE: c.
Quite often, vents are the only safety relief device available to prevent pressure or vacuum damage.
Other potential auxiliary problem areas: i. ii. iii.
Malfunction of gauging system. Floating roof drains. Plugged drain sumps (debris or ice).
ITAC API RP 575 Summary, 2007 Page 3-8
SECTION 6 - FREQUENCY OF INSPECTION API Standard 653 provides requirements for inspection frequency, including factors to consider in determining inspection frequency. 6.2
Condition-based Inspection Scheduling
There are two calculations listed: Remaining Life and Corrosion Rate. For exam purposes, commit both calculations to memory. The two main aspects to consider when inspecting a tank: a. b.
the rate at which deterioration is proceeding; and the safe limit of deterioration.
The following may be used for most common forms of deterioration, metal corrosion, the rate of metal loss and the remaining life of a tank component. t actual - t minimum corrosion rate
Remaining life = Where:
Remaining life = the remaining life of a tank component, in years t actual =
the thickness measured at the time of the inspection for a given location or component used to determine the minimum allowable thickness, in inches.
t minimum = the minimum allowable thickness for a given location or component, in inches. Corrosion rate
=
t previous -= t actual in years between t actual and t previous
t previous =- thickness at the same location as t actual measured during a previous inspection, in inches.
ITAC API RP 575 Summary, 2007 Page 3-9
SECTION 7 - METHODS OF INSPECTION AND INSPECTION SCHEDULING The first part of this section deals with safety aspects of entry. The next section is a current list of tools commonly used in tank inspection and a suggested list of equipment that might be needed in tank inspection. 7.2
External Inspection of In-Service Tank See Appendix A of this Recommended Practice. 7.2.3
Foundation Inspection Refer to API Standard 653 for limitation.
7.2.4
Anchor Bolt Inspection The condition of anchor bolts can usually be determined by visual inspection. The hammer and UT thickness methods are also described in this section.
7.2.5
Grounding Connection Inspection The total resistance from tank to earth should not exceed approximately 25 ohms.
7.2.6
Protective Coating Inspection Rust spots, blisters, peeling, cracking and coating due to lack of adequate bond, are all types of common paint failure.
7.2.7
Insulation Inspection Under insulation corrosion is now considered to be a more severe problem than previously thought. a.
A visual examination is usually, but not always, sufficient to spot problem areas.
b.
Areas to be more closely checked include: i. ii. iii. iv. v.
Around all nozzles and appurtenances, especially if the caulking bond is loose or points for casual water entry is evident. Around saddles where movement or expansion may have damaged insulation or seal. Around open-bubbles on polyurethane foam systems. Along bottom edge where moisture “wicking” may have occurred. Along roof to shell junction, unless this area is protected by an overhand “rat-guard” type insulation support brackets (where block insulation is used). ITAC API RP 575 Summary, 2007 Page 3-10
7.2.8
Tank Shell Inspection 7.2.8.1
Thickness Measurements Ultrasonic-thickness measurements should be conducted only by trained personnel using a properly calibrated thickness measurement instrument and an appropriate thickness measurement procedure.
7.2.8.3
Caustic Cracking If caustic or amine is stored in a tank, the tank should be checked for evidence of damage from caustic stress corrosion cracking, sometimes referred to as caustic embrittlement.
7.4
Internal Inspection 7.4.4
Tank Bottoms This section suggests inspection of the entire tank bottom by using Magnetic Flux Leakage, looking for bottom side corrosion. Other UT type techniques may also be used. A-scan or shear wave ultrasonic testing may be used under specific conditions. Hammertesting is also mentioned as a testing technique.
7.4.6
Testing for Leaks The usual types of tests are mentioned, hydrostatic tests, vacuum box tests, external water bottom tests and tracer gas tests. Another method being used successfully is the injection of inert gas with a tracer gas under the tank. Instruments capable of detecting a few parts per million (PPM) of the tracer gas are then used for “sniffing” for leaks on the topside of the tank floor. An advantage of such a method is that welded repairs can be made immediately with the inert gas under the bottom and a re-check can be made immediately after repairs.
7.5
Testing of Tanks The word testing, as used in this subsection, applies only to the process of filling the tank with a liquid or gaseous fluid, at the appropriate level or pressure, test the tank for strength or leaks.
ITAC API RP 575 Summary, 2007 Page 3-11
7.6
Inspection Checklists Inspection checklists should be used judiciously by the inspector as “memory joggers” for issues and items to be checked during inspection, both internal and external. See API Std 653 Appendix C.
8.0
Leak Testing and Hydraulic Integrity of the Bottom
9.0
Integrity of Repairs and Alterations
Appendix A Selected Non-Destructive Examination (NDE) Methods Appendix B Similar Service Evaluation Tables Appendix C – Selected Bibliography
ITAC API RP 575 Summary, 2007 Page 3-12
Section 4 RP 651 Summary-07
API-RP-651 CATHODIC PROTECTION OF ABOVEGROUND PETROLEUM STORAGE TANKS SECOND EDITION, DECEMBER 1997 SECTION 1 - GENERAL 1.1
Scope Recommended practices covered by this presentation is to present procedures, practices, information and guidance for achieving effective corrosion control on above ground hydrocarbon storage tank bottoms. It contains provisions for the application of cathodic protection to existing and new storage tanks. Corrosion control methods based on chemical control of the environment and the use of protective coatings are not covered in detail. Certain recommended practices may also be applicable to tanks in other than hydrocarbon service. This is intended to serve only as a guide. Specific cathodic protection design is not provided. Every tank condition is not covered. Standardization is precluded because of the varied conditions for field application.
2.0
Referenced Publications
3.0
Definitions Definitions in this section reflect the common usage among practicing corrosion control personnel. In many cases, in the interests of brevity and practicality, the strict scientific definitions have been abbreviated or paraphrased. 3.1 aboveground storage tank: A stationary container of greater than 500 barrel capacity, usually cylindrical in shape, consisting of a metallic roof, shell, bottom, and support structure where more than 90 percent of the tank volume is above surface grade. 3.2 anode: An electrode of an electrochemical cell at which oxidation (corrosion) occurs. Antonym: cathode. 3.3 anode bed: Consists of one or more anodes installed below the earth’s surface for the ITAC API 651 Summary, 2007
purpose of supplying Cathodic protection. 3.4 backfill: Material placed in a hole to fill the space around anodes, vent pipe, and buried components of a cathodic protection system. Anodes can be prepackaged with backfill material for ease of installation. 3.5 breakout piping/tanks: All piping associated with the transfer of products in and out of storage tanks. 3.6 cathode: An electrode of an electrochemical cell at which a Page 4-1
reduction reaction occurs. Antonym: anode.
usually a metal, that results from a reaction with its environment.
3.7 cathodic protection: A technique for preventing corrosion by making the entire surface of the metal to be protected act as the cathode of an electrochemical cell.
3.13 current density: The current per unit area flowing to or from a metallic surface.
3.8 chime (or chine): The portion of the tank bottom steel floor plate that extends horizontally past the outside vertical surface of the shell (i.e., the external lip formed at the base of the tank where the bottom steel floor plate protrudes and is welded to the bottom of the shell, around the entire tank perimeter). Also referred to as bottom extension 3.9 coke breeze: A carbonaceous backfill material. 3.10 concentration corrosion cell: A form of localized corrosion initiated by the difference in metal ion or oxygen concentration due to crevices or deposits. (NACE definition: An electrochemical cell, the electromotive force of which is caused by a difference in concentration of some component in the electrolyte. [This difference leads to the formation of discrete Cathodic and anodic regions.]) 311 continuity bond: A metallic connection that provides electrical continuity.
3.12 corrosion: The deterioration of a material, ITAC API 651 Summary, 2007
3.14 current requirement test: Creates direct current flow from a temporary ground bed to the structure to be protected to determine the amount of current necessary to protect that structure. 3.15 deep anode bed: One or more anodes installed vertically at a nominal depth of 15m (50 ft) or more below the earth’s surface in a single drilled hole for the purpose of supplying cathodic protection. 3.16 differential aeration cell: An electrochemical cell the electromotive force of which is due to a difference in air (oxygen) concentration at one electrode as compared with that at another electrode of the same material. 3.17 electrical isolation: The condition of being electrically separated from other metallic structures and the environment. 3.18 electrochemical cell: An electrochemical system consisting of an anode and a cathode immersed in an electrolyte so as to create an electrical circuit. The anode and cathode may be separate metals or dissimilar areas on the same metal. The cell includes the external circuit which permits the flow of electrons from the anode toward the cathode. 3.19 electrode potential: The potential of an electrode as Page 4-2
measured against a reference electrode. (The electrode potential does not include any resistance losses in potential in either the electrolyte or the external circuit. It represents the reversible work required to move a unit charge from the electrode surface through the electrolyte to the reference electrode). 3.20 electrolyte: A chemical substance containing ions that migrate in an electric field. For the purposes of this recommended practice, electrolyte refers to the soil or liquid adjacent to and in contact with the bottom of an aboveground petroleum storage tank, including the moisture and other chemicals contained therein. 3.21 environmental cracking: The brittle fracture of a normally ductile material in which the corrosive effect of the environment is a causative factor. 3.22 external circuit: Consist of the wires, connectors, measuring devices, current sources, etc., that are used to bring about or measure the desired electrical conditions within an electrochemical cell. It is this portion of the cell through which electrons travel. 3.23 external liner: A system or device, such as a nonconductive membrane, installed beneath a storage tank, in or on the tank dike, to contain any accidentally escaped product. 3.24 foreign structure: Any metallic structure that is not an ITAC API 651 Summary, 2007
intended part of the system in question. 3.25 galvanic anode: A metal that, because of its relative position in the galvanic series, provides sacrificial protection to another metal that is more noble, when coupled in an electrolyte. These anodes are the source of current in one type of cathodic protection. 3.26 galvanic cathodic protection: The reduction or prevention of corrosion of a metal in an electrolyte by electrically connecting it to a more anodic metal. 3.27 galvanic series: A list of metals and alloys arranged according to their relative potentials in a given environment. 3.28 holiday: A discontinuity in a protective coating that exposes unprotected surface to the environment. 3.29 impressed current: An electric current supplied by a device employing a power source that is external to the electrode system. (An example is direct current for cathodic protection). 3.30 interference bond: A metallic connection designed to control electrical current interchange between metallic systems. 3.31 IR drop: The voltage generated across a resistance by an electrical current in accordance with Ohm's Law: E=I X R. For the purpose of this recommended practice, IR drop is the portion of a structure-to-soil Page 4-3
potential caused by a high resistance electrolyte between the structure and the reference electrode or by current flow from the anodes to the tank bottom. 3.32 isolation: Electrical isolation. 3.33 membrane: A thin, continuous sheet of non conductive synthetic material used to contain and/or separate two different environments. 3.34 oxidation: The loss of electrons by a constituent of chemical reaction. 3.35 polarization: The change from the open circuit potential of an electrode resulting from the passage of current. (In this recommended practice, it is considered to be the change of potential of a metal surface resulting from the passage of current directly to or from an electrode). 3.36 rectifier: A device for converting alternating current to direct current. Usually includes a step-down AC transformer, a silicon or selenium stack (rectifying elements) , meters and other accessories when used for cathodic protection purposes. 3.37 reduction: The gain of electrons by a constituent of a chemical reaction. 3.38 reference electrode: A device whose open circuit potential is constant under similar conditions of measurement. 3.39 release prevention barrier (RPB): Includes steel bottoms (when used in a double bottom ITAC API 651 Summary, 2007
or secondary containment system), synthetic materials, clay liners, and all other barriers or combination of barriers placed in the bottom of, or under an aboveground storage tank, which have the following functions: (a) preventing the escape of stored product, and (b) containing or channeling released material for leak detection. 3.40 resistor: A device used within an electrical circuit to control current flow. 3.41 secondary containment: A device or system used to control the accidental escape of a stored product so it may be properly recovered or removed from the environment. For the purposes of the recommended practice, secondary containment refers to an impermeable membrane. 3.42 shallow anode bed: A group of cathodic protection anodes installed individually, spaced uniformly, and typically buried less than 20 feet below grade. 3.43 shunt: A conductor of a known electrical resistance through which current flow may be determined by measurement of the voltage across the conductor. 3.44 stray current: Current flowing through paths other than the intended circuit.
3.45 stray current corrosion: Corrosion resulting from direct current flow through paths other than the intended circuit. Page 4-4
3.46 stress corrosion cracking: The fracture of a metal by the combined action of corrosion and tensile stress that may be well below the tensile strength or even the yield strength of the material.
3.50 test lead: An electrically conductive cable attached to a structure and leading to a convenient location. It is used for the measurement of structure-toelectrolyte potentials and other measurements.
3.47 structure-to-electrolyte voltage (also structure-to-soil potential or pipe-to-soil potential): The voltage difference between a metallic structure and the electrolyte which is measured with a reference electrode in contact with the electrolyte.
3.51 test station: A small enclosed box-like housing and the usual termination point of one or more test leads.
3.48 structure-to-structure voltage (also structure-tostructure potential): The difference in voltage between a metallic structures in a common electrolyte.
3.52 voltage: Refers to an electromotive force, or a difference in electrode potentials expressed in volts. Also known as a potential. 3.53 water bottom: A water layer in the bottom of a tank caused by separation of water and product due to differences in solubility and specific gravity.
3.49 tank pad: Another name for a tank cushion.
ITAC API 651 Summary, 2007
Page 4-5
SECTION 4- CORROSION OF ABOVEGROUND STEEL STORAGE TANKS 4.1.1
Corrosion may be defined as the deterioration of a metal due to a reaction to its environment. Corrosion of steel structures is an electrochemical process. The corrosion process occurs when: a. b. c.
Areas with different electrical potentials exist on the metal surface. These areas must be electrically connected. Areas must be in contact with an electrolyte. Moist soil is the most common electrolyte for external surfaces of the tank bottom. Water and sludge are, generally, the electrolytes for internal surfaces. NOTE:
There are four (4) components in each corrosion cell: 1. 2. 3. 4.
4.1.2
An anode A Cathode A metallic path connecting the anode and cathode. (See Fig. 1) An electrolyte
Many forms of corrosion exist. The two (2) most common (relative to tank bottoms) are general and pitting corrosion. a. b.
General type: Thousands of microscopic corrosion cells occur on an area of the metal surface resulting in relatively uniform metal loss. Pitting type: Individual cells are larger and distinct anode and cathode areas can be identified. NOTE:
Corrosion occurs at the Anode. Metal loss may be concentrated within relatively small areas with substantial surface areas unaffected.
4.1.3 through 4.1.5 Conditions that influence which areas of a surface become anodic or cathodic and/or corrosion cells are: a. b. c. d. e. f. g.
Composition of the metal. Differences in electrochemical potential (i.e., uneven distribution of alloying elements or contaminates within the metal structure). Differences between the weld bead, the heat affected zone and the parent metal. Physical and chemical properties of the electrolyte. Differences in oxygen concentrations. Soil characteristics (i.e., dissolved salts, moisture content, pH, etc.). Clay, wood or other debris in bottom contact. ITAC API 651 Summary, 2007
Page 4-6
4.2
Corrosion Mechanisms 4.2.1
Stray current corrosion occurs when stray currents (also known as interference currents) travel through the soil electrolyte and on to structures for which they are not intended. NOTE:
The most common, and potentially more damaging, stray currents are direct currents (i.e., grounded DC electric power systems) such as electric railroads, subways, welding machines, impressed current cathodic protection systems and thermoelectric generators.
The severity of corrosion resulting from interference currents depend on the following: a. b. c. d. 4.2.2
Separation and routing of the interfering and affected structures and the location of the interfering current source. Magnitude and density of the current. Quality of or absence of a coating on the affected structure. Presence and location of mechanical joints having high electrical resistance.
Galvanic Corrosion occurs when two (2) metals with different compositions (thus different electrolytic potentials) are connected in an electrolyte (usually soil). (See Fig. 4). NOTE:
4.3
Current flows from the more active metal (anode) to the less active metal (cathode) with resulting accelerated attack at the anode. Examples: Bronze check valve to steel piping. Stainless Steel or Copper pipe to steel tank.
Internal Corrosion may occur on the inside surface of a tank bottom. Factors influencing severity are: a. b. c. d.
Conductivity (2 function of dissolved solids). Suspended solids pH level Dissolved gases such as CO2, H2S or O2.
ITAC API 651 Summary, 2007
Page 4-7
SECTION 5 - DETERMINATION OF NEED FOR CATHODIC PROTECTION 5.1.4
Limitations Cathodic protection is an effective means of corrosion control only if it is possible to pass electrical current between the anode and cathode (i.e., tank bottom). Many factors can either reduce or eliminate the flow of electrical current, reducing protection effectiveness. Such factors include: a. b. c. d.
Foundations such as concrete, asphalt or oiled sand. An impervious lining between the tank bottom and anodes such as in secondary containment systems. High resistance soil or rock foundations. Old storage tank bottoms left in place when a new bottom is installed.
SECTION 6 - METHODS OF CATHODIC PROTECTION FOR CORROSION CONTROL 6.1
Introduction Cathodic protection is a technique for preventing corrosion by making the entire surface of the metal act as the cathode of an electrochemical cell. The two (2) methods of protection are: a. b.
6.2
Galvanic Impressed current.
Galvanic Systems 6.2.1
Use of a metal more active than the structure to be protected to supply the current required to stop corrosion. See Table 3 (Page 10 code) for a partial galvanic series. The more active metal is called a sacrificial anode. Example: The anode is electrically connected to the structure and buried in the soil. A galvanic corrosion cell develops and the active metal anode corrodes (is sacrificed) while the metal structure (cathode) is protected. NOTE:
6.2.2
Metals commonly used as sacrificial anodes in soil are magnesium and zinc (in either cast or ribbon form). Usually distributed around the perimeter of the tank or buried beneath the bottom.
Advantages of Galvanic Systems a. b. c. d. e. f.
No external power supply is required. Installation is easy. Capital investment is low. Minimum maintenance costs. Interference problems (stray currents) are rare. Less frequent monitoring required. ITAC API 651 Summary, 2007
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6.2.3
Disadvantages of Galvanic Systems a. b. c. d.
6.3
Driving potential is limited. Current output is low. Method is limited to use in low-resistivity soils. Not practical for protection of large bare structures.
Impressed Current Systems 6.3.1
Uses DC usually provided by a rectifier (i.e., device for changing AC into DC). DC flows from the rectified to the buried impressed current anode.
6.3.2
Advantages of Impressed Current Systems a. b. c. d.
6.3.3
Disadvantages of Impressed Current Systems a. b. c. d. e. f. g.
6.3.4
Availability of large driving potential. High current output for protecting large structures. Capability of variable current output. Applicable to almost any soil resistivity.
Interference problems (i.e., stray currents) on foreign structures. Loss of AC power causes loss of protection. Higher costs (maintenance and operating). Higher capital costs. Safety aspects of rectifier location. Safety aspects of negative lead connections. More frequent monitoring.
Rectifiers - Two (2) major components: a. b.
Step-down transformer (reduces AC supply voltage). Rectifying elements to provide DC output.
NOTE:
6.3.5
Silicon rectifiers are more efficient, but are troubled by power surges, (i.e., lightening prevention devices required). Selenium rectifiers are used, but have decreased life span if ambient temperature exceeds 130°F.
Impressed Current Anode materials are graphite, steel, high silicon cast iron or mixed metal oxides on titanium. Usually buried in a coke breeze backfill (reduces circuit resistance), in remote groundbeds, distributed around or under the tank or installed in deep groundbeds.
ITAC API 651 Summary, 2007
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SECTION 7 - DESIGN OF CATHODIC PROTECTION SYSTEMS When dealing with your client/customer, be aware of certain conditions that may influence your job assessment/evaluation. These items include: 7.2.1
Anything that acts as a barrier to the flow of current will prevent the application of cathodic protection.
7.2.2
Tank bottom replacement has a significant impact on protection effectiveness. If cathodic systems exist, or installation is planned for the new bottom, the old bottom must be removed. NOTE:
If the old bottom remains in place, even with cathodic systems installed between the old and new bottoms, future problems may occur. If a conductive electrolyte exists between the bottoms, the current flow and metal loss will be from the new bottom.
7.2.5.1
Secondary containment systems between bottoms (i.e., impermeable membranes) have both good and bad features relative to cathodic protection. 7.2.5.2
Advantages a. b. c.
7.2.5.3
Contains leaks and prevents ground contamination. Eliminates current flow between bottoms. Prevents ground water wicking into sand pad.
Disadvantages a. b. c.
Future addition of cathodic protection impossible. Membrane acts as a basin to contain electrolyte. With leak, traps hydrocarbon, becomes "hotwork" issue.
ITAC API 651 Summary, 2007
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SECTION 8 - CRITERIA FOR CATHODIC PROTECTION: When has adequate protection been achieved and does it still exist? 8.2
Protection Criteria Developed from lab experiments or from existing, successful systems. Minimum requirements are listed below. 8.2.2.1 A negative (cathodic) potential of at least 850 mV with the cathodic protection current applied. 8.2.2.2 A negative polarized potential of at least 850 mV relative to a CSE. 8.2.2.3 A minimum of 100 mV of cathodic polarization measured between the tank bottom metallic surface and a stable reference electrode contacting the electrolyte.
8.3
Measurement Techniques 8.3.1
The standard method of determining the effectiveness of cathodic protection on a tank bottom is the tank-to soil potential measurement. NOTE:
1.
2.
Measurement is performed using a high-impedance (i.e., resistance) voltmeter and a stable, reproducible reference electrode contacting the electrolyte. (See Fig. 10) Perimeter measurement may not represent potential at the center of the tank bottom.
SECTION 9 - INSTALLATION OF CATHODIC PROTECTION SYSTEMS (No specific notes) SECTION 10 - INTERFERENCE CURRENTS (No specific notes)
ITAC API 651 Summary, 2007
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SECTION 11 - OPERATION AND MAINTENANCE OF CATHODIC PROTECTION SYSTEMS 11.1
Introduction Coupled with operation and maintenance, Field inspection surveys (to determine that cathodic protection has been established and that it is currently effective) should be established. A few items that should be considered include: a. b. c.
Conditions that affect protection are subject to change with time. Changes may be required to maintain (or even establish) protection. If tanks are empty, large areas of the bottom may not be in contact with underlying soil. Potential surveys, may therefore, be misleading.
NOTE: d.
Potential surveys should be made with sufficient product gauge so as to maximize bottom-cushion contact.
Initial surveys (on new installation) should not be conducted until after adequate polarization (i.e., a positive or negative condition) has occurred. This is generally 6-18 months after system energized.
11.3.1 Surveys should include one or more of the following: a. b. c. d. e. f. g. h. 11.4
Structure-to-soil potential. Anode current. Native structure-to-soil potentials. Structure-to-structure potential. Piping to tank isolation (if protected separately). Effect an adjacent structures. Continuity of structures (if protected as single structure). Rectifier DC volts, DC amps, efficiency and tap settings.
Cathodic Protection Records Depending on need, circumstance and customer direction, the following should be considered as permanent record needs: a. b. c. d. e f. g.
Design and location of insulating devices. Results of current requirement tests, where made and procedures used. What was native structure-to-soil potential before current was applied. Results of soil resistivity (resistance) test at the site, where made and procedures used. Type of system (i.e., sacrificial anode, impressed current, etc. ). Repair of rectifiers, other DC power sources required. Repair/renewal of anodes, connections or cable.
ITAC API 651 Summary, 2007
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Section 5 652 Summary-07
API RP - 652 LINING OF ABOVEGROUND PETROLEUM STORAGE TANK BOTTOMS SECOND EDITION, DECEMBER 1997 SECTION 1 - GENERAL 1.1
Scope This recommended practice describes the procedures and practices for achieving effective corrosion control in aboveground storage tanks by application of tank bottom linings to existing and to new storage tanks. This recommended practice also provides information and specific guidance for tanks in hydrocarbon service. Some of the practices may also be applicable for other services. NOTES: 1. 2. 3.
This does not designate specific bottom linings for all situations because of the wide variety of service environments. This recommended practice is a guide only. Detailed lining specifications are not included. SECTION 2 - REFERENCED PUBLICATION
2.0
Referenced Publications
ITAC API RP-652 Summary, 2007
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3.0
DEFINITIONS 3.1 aboveground storage tank: A stationary container, usually cylindrical in shape, consisting of a metallic roof, shell, bottom and support structure where more than 90% of the tank volume is above surface grade. 3.2 adduct: A curing agent, generally an amine, that has been combined with a portion of the resin, usually an epoxy. 3.3 amine: An organic compound having amino functional groups which provide chemical reactivity and utility as a curative for epoxy and other resins. 3.4 anchor pattern: Surface profile or roughness. 3.5 anode: The electrode of an electrochemical cell at which oxidation (corrosion) occurs. Electrons flow away from the anode in the external circuit. Corrosion usually occurs and metal ions enter the solution at the anode. * Antonym: cathode. 3.6 aromatics: Strong hydrocarbon solvents whose chemical structure has an unsaturated ring with delocalized pi electrons. Benzene, toluene and xylene are common examples of aromatic solvents. 3.7 Bisphenol-A polyester: A polyester whose chemical structure incorporates BisphenolA into the resin molecule in place of some or all of the glycol. The solid resin is generally provided a solution in styrene, which acts as a solvent and as a cross-linking agent for the resin. ITAC API RP-652 Summary, 2007
3.8 cathode: An electrode of an electrochemical cell as which a reduction is the principle reaction. Electrons flow toward the cathode in the external circuit. * Antonym: anode 3.9 cathodic protection: A technique for to reduce corrosion of a metal surface by making that surface the cathode of an electrochemical cell. 3.10 coal tar: A black hydrocarbon residue remaining after coal is distilled. 3.11 coal tar epoxy: A coating in which the binder is a combination of coal tar and epoxy resin. 3.12 coating: See definition for lining. 3.13 copolymer: A large molecule whose chemical structure consists of at least two (2) different monomers. 3.14 corrosion: The deterioration of a material, usually a metal, because of a reaction with its environment. 3.15 curing: The setting up, or hardening, generally due to a polymerization reaction between two (2) or more chemicals (resin and curative). 3.16 dew point: Pertains to the temperature at which moisture condenses from the atmosphere. 3.17 differential aeration cell: An electrochemical cell , the electromotive force of which is Page 5-2
due to a difference in air (oxygen) concentration at one electrode as compared with that at another electrode of the same material. 3.18 electrochemical cell: A system consisting of an anode and a cathode immersed in an electrolyte so as to create an electrical circuit. The anode and the cathode may be different metals or dissimilar areas on the same metal surface. 3.19 electrolyte: A chemical substance containing ions that migrate in an electric field. 3.20 epoxy: Resin containing epoxide (oxirane) functional groups that allow for curing by polymerization with a variety of curatives. Epoxy resins are usually made from Bisphenol-A and/or Bisphenol-F and epichlorohydrin. 3.21 forced-curing: Acceleration of curing by increasing the temperature above ambient, accompanied by forced air circulation. 3.22 holiday: A discontinuity in a coating film that exposes the metal surface to the environment. 3.23 isophthalic polyester: A resin polymerized from isophthalic acid (or anhydride), ethylene or propylene glycol and malaic acid (or anhydride). The solid resin is generally provided as a solution in styrene, which acts as a solvent and as a crosslinking agent for the resin. 3.24 lining: A coating bonded to the internal surfaces of a tank ITAC API RP-652 Summary, 2007
to serve as a barrier to corrosion by the contained fluids. 3.25 mil: One one-thousandth of an inch (0.001"). One mil = 25.4 um; it is common practice to use 1 mil = 25 um. 3.26 mill scale: An oxide layer formed on steel during hotforming operations, typically “gun-metal” blue in color. 3.27 phenolic: A resin of the phenol formaldehyde type. 3.28 polyamide: A resin whose chemical structure contains adjacent carbonyl and amino functional groups that is often used as a curative for epoxy resins. Commercially available polyamides are reaction products of dimerized and trimerized fatty acids with ammonia or polyamines. 3.29 polyamidoamine: : A resin whose chemical structure contains adjacent carbonyl and amino functional groups that is often used as a curative for epoxy resins. Commercially available polyamidoamines are reaction products of monofunctional fatty acids and amines. 3.30 resin: A natural or synthetic substance that may be used as a binder in coatings. 3.31 thick-film lining: A lining with a dry film thickness of 20 mils (0.51 um) or more). 3.32 thick-film reinforced lining: See 6.3 for interpretation. 3.33 thin-film lining: A lining with a dry film thickness less than 20 mils (0.51 um). Page 5-3
3.34 vinyl-ester: A polyester that usually contains Bisphenol-A in the resin backbone and two vinyl groups for polymerization reactivity. The solid resin is generally provided as a solution in styrene, which acts as a solvent and as a cross-linking agent for the resin. 3.35 vinyl group: A functional group on a resin molecule that contains a carbon-to-carbon
ITAC API RP-652 Summary, 2007
double bond at the end of the molecule. 3.36 Volatile organic compound (VOC): Compounds that have a high vapor pressure [greater than 0.27 kPa (2 mm of mercury) at 25oC] and low water solubility, excluding methane. VOCs typically are industrial solvents, fuel oxygenates, or components of petroleum fuels
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SECTION 4 - CORROSION MECHANISMS 4.1
General The common mechanisms of internal storage tank bottom corrosion include: a. b. c. d. e. f.
4.2
Chemical corrosion Concentration cell corrosion Galvanic cell corrosion Corrosion caused by sulfate-reducing bacteria Erosion corrosion. Fretting-related corrosion
Chemical Corrosion a.
Normally seen in environmental and product clean-up tanks. Concentrated acids, added to water (with heat) to break emulsion of oil and water, becomes deluded. Diluted acid is much more corrosive than stronger acids. b.
4.3
Chemical attack also occurs in caustic, sulfuric acid, ballast water and water neutralization services.
Concentration Cell Corrosion Occurs in lower oxygen concentration areas (i.e., surface deposit, mill scale or crevice). NOTE:
4.4
Recognized as pitting or in a significant localized metal loss area.
Galvanic Cell Corrosion Formation of a bi-metallic corrosion couple due to the presence of an electrolyte (i.e., dissolved oxygen). The common locations for occurrence are: a. b.
Breaks in mill scale. HAZ adjacent to welds
NOTE: Also noted by significant localized metal loss. 4.5
Corrosion Caused by Sulfate-Reducing Bacteria a. b. c.
Phenomenon recognized but not understood. Usually negligible, occasionally service. Thought to be associated with concentrated cell corrosion, due to deposits forming a barrier to the diffusion of dissolvedoxygen.
ITAC API RP-652 Summary, 2007
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4.6
Erosion Corrosion Normally occurs in mixing tanks where soil particles or small aggregate are present and movement occurs (i.e., waste water treating or mixing, adjacent to mixers in crude tanks). The movement of aggregate causes abrasive attack. Normally seen as "well defined" loss pattern.
4.7
Fretting-related Corrosion Often seen as “striker” or bearing plate damage. This is associated with “grounding” of a floating roof.
ITAC API RP-652 Summary, 2007
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SECTION 5 - DETERMINATION OF NEED for TANK BOTTOM LININGS 5.1
General Tank bottoms normally fabricated from carbon steel plate sections typically 1/4" (6 mm) thick. Annular floor plate rings may be thicker (up to 1/2" (12 mm). Sketch plates (under shell) of 5/16" plate may often be found in older tanks. The need for an internal tank bottom lining is generally based upon one or more of the following: a. b. c. d. e. f. g.
5.2
Corrosion prevention Tank design Tank history Environmental considerations Flexibility for service change Upset conditions Federal, State or local regulations.
Linings for Corrosion Prevention Proper selection and application of bottom linings can prevent internal bottom corrosion. NOTE:
5.3
Tank Corrosion History a. b. c.
Consider corrosion history when determining need for lining. Consider history of other tanks in similar service. Some important considerations are: i. ii. iii. iv. v.
5.4.
If the tank bottom measurements indicate that a "t" of 0.100" exists, or will be present prior to the next schedule turnaround, then a recommendation for applying a lining should be strongly considered.
Where is corrosion problem occurring (product side, soil side, outer periphery, etc.)? How fast is corrosion proceeding? Has there been a significant change in corrosion rate? What type of corrosion is occurring? Has through-bottom penetration occurred?
Tank Foundation Inadequate foundation can cause tank settlement, bottom flexing may occur, causing the internal lining to fail by cracking.
ITAC API RP-652 Summary, 2007
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SECTION 6 - TANK BOTTOM LINING SELECTION 6.1
General: Tank bottom linings can generally be divided into two (2) classes: a. b.
6.2
Thin films (less than 20 mils). Thick films (20 mils or more).
Thin-film types Frequently based on epoxy or epoxy-copolymer resins. See Table 1 (Lining Systems) for generic types and their suitability for various services. NOTE:
6.2.1
All linings that are employed to protect tank bottoms must be resistant to water.
Advantages - Disadvantages (Thin Film Type) a.
Advantages: i. ii.
b.
New plate provides a smooth surface that can easily be made ready for coating application. Lower cost (due to ease of application).
Disadvantage: Corrosion creates a rough/pitted surface that is difficult to completely coat and protect.
6.3
Thick-Film types Commonly reinforced with glass flake, chopped glass fibers, glass mat, glass cloth or organic fibers. a.
Generic types and where used. (See Table 2)
NOTE: b.
Additional data available in NACE Publication 6A187.
Specific notes relative to thick-film types: i. ii. iii. iv. v. vi
All applied over a white or near-white abrasive blast. Primer frequently required. Dependent upon thickness required - multiple coats needed. Resin-rich topcoat required. Polyesters require wax addition to ensure timely cure. Check with manufacturer for specifics (chemical immersion, elevated temperature tolerance, limitations in specific products, etc.). ITAC API RP-652 Summary, 2007
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6.3.1
Advantages (thick-film types): Advantages: a. b. c. d.
6.3.2
Less susceptible to mechanical damage. Provides additional strength to bridge over small bottom perforations. Not as sensitive to pitting and other surface irregularities during installation. Less need for removal of sharp corners, edges, offsets and weld spatter.
Disadvantages (thick-film types): Disadvantages: a. b. c.
6.4
Design of Storage Tank Bottom Linings a.
Normal data or knowledge required: i. ii. iii. iv. v. vi.
b.
Linings should extend 18-24 inches up the shell. Transition area (from bottom horiz. to shell vert.), is a common failure area. Proper support, especially with thick-films are critical in this area. With thin-film types, desired film thickness normally requires 2-3 coats. Thick-films range from 1-4 coats. New tanks, or where only internal loss has occurred may require 35-55 mils. Older bottoms, corroded on both sides may require 80-120 mils (usually reinforced).
More specific data: i. ii.
6.5
Require more time and effort to apply. More expensive. Makes future inspections more difficult.
"White" (SSPC-SP5/NACE #1) or a "near-white" (SSPCSP10/NACE #2) abrasive blast cleaner. Anchor pattern (surface roughness) required is generally between 1.5 and 4 mils, depending on lining selection.
Exceptional Circumstances Affecting Selection Be sure to take into consideration: a. b. c. d.
Corrosion history or corrosion potential Elevated temperatures. Above 160°F is critical. Product purity. Thin-films may be sufficient. Liner may contaminate product. ITAC API RP-652 Summary, 2007
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NOTE:
NACE Publ. TMO174 or Military Spec MIL-C-4556D may be of assistance if manufacturer cannot furnish special data.
ITAC API RP-652 Summary, 2007
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SECTION 7 - SURFACE PREPARATION 7.1
General
b.
a. Surface preparation is a critical part of lining operation. Surface preparation is performed to provide the appropriate combination of surface cleanliness/surface profile (anchor profile) required to establish good chemical and mechanical adhesion of the coating resin to the substrate (i.e., steel). Inadequate surface preparation is a major cause of lining failure. However, a well prepared surface becomes meaningless if all of the abrasive material (i.e., sand, etc.) is not removed prior to primer/liner application. In such event, a lack of adhesion, future peeling or disbonding failure can be expected. Continuous immersion presents a sever exposure.
NOTE:
7.2
Precleaning a. b.
7.3.
NACE No. 1/SSPC-SP5 (white metal finish) or NACE No. 2/SSPCSP10 (near-white) is often specified as the minimum degree of surface cleanliness.
Before blasting, all contaminants (i.e., oil, tar, grease, salt, etc.) must be removed. Solvent cleaning (SSPC-SP1), high pressure water or steam cleaning should be considered. Fresh water wash after solvent cleaning, may be required to remove soluble salts and cleaning chemicals.
Bottom Repair - Weld Preparation a. Most common repair of perforations is welded steel patches. Another repair method is to epoxy a 12 gauge steel plate over the bottom perforation prior to thick-film (reinforced) linings being installed. SAFETY NOTE: b.
7.4
Weld repair may be disallowed if tank pad has been contaminated with flammable materials.
Remove sharp edges, corners and protrusions. Chipping or power grinding most common removal method.
Abrasive Blasting Do Not Blast when steel temperature is less than 5°F(3°C) above the dew point or if the relative humidity is greater than 80%. In particularly humid areas, such as coastal regions, potential solutions might be selective timing, which may influence work schedules, or perhaps the use of forced air injection. NOTE:
Liner applications must be conducted when surface condition is appropriate. Delay (between blast and application) will produce poor results. When in doubt, restore surface preparation to the necessary degree. ITAC API RP-652 Summary, 2007
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7.5
Surface Profile or Anchor Pattern a. b. c.
Match profile to accommodate selected liner. Refer to material manufacturer's recommendation. Typical anchor pattern is 1.5 to 4 mils. This generally increases with liner thickness.
7.6
Types and Quality of Abrasives
7.7
Removal of Dust
ITAC API RP-652 Summary, 2007
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SECTION 8 - LINING APPLICATION 8.1
General a. b. c. d.
8.2
Application Guidelines a. b. c. d.
8.4
SSPC-PA1 and NACE 6F164 - Good painting practice. Establish and adhere to proper mixing practices. If conflicts arise (between owner/user; liner applicator or material manufacturer) over any aspect of the job, resolve them prior to beginning the project. Consider restraints imposed by steel temperature and relative humidity.
Lining Thickness a. b.
8.5
Avoid disbonding or delamination by following manufacturer's recommendations. Stick to time interval (between coats) recommended by owner's specifications or manufacturer. SSPC-PA1 is a dependable procedure to follow. Establish and adhere to recommended drying (curing) period. Customers often get impatient.
Insufficient film thickness will not provide adequate coverage or protection. Excessive thickness can compromise adhesion and integrity. Thicker is not always better.
Lining Curing a.
Lining failure is attributed to: i. ii. iii.
NOTE: b.
Improper preparation. Improper application. Inadequate curing. Adhesion and film integrity depend upon above listed items.
Proper curing conditions may be aided by force-curing (i.e., circulating warmed, dehumidified air).
ITAC API RP-652 Summary, 2007
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Notes API RP 652 (Reinforced Glass-epoxy Internal Lining 65 Mils Thick) Clean and repair the tank bottom (install lap weld steel plate patches 3/16" or 1/4" and weld build-up). Abrasive blast per API 652 specifications, remove all residue (air blow, broom sweep and vacuum) remove all moisture. Hand trowel epoxy in the corner area and radius all transitions, and around patch plates. Consult a "Technical Representative" for the product being installed, include a job site visit. If the following conditions are correct: Proper blast profile Proper material mixture Application equipment properly functioning Material specifications correct Proper thickness applied Proper curing procedure followed Weather restraints are observed The lining will be satisfactory and last 10 - 20 years.
ITAC API RP-652 Summary, 2007
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SECTION 9 - INSPECTION Items 9.1 (General) through 9.3.4 (Discontinuities) list some qualifications, parameters and procedures to assist or guide in the area of Inspection. Without going into detail or explanation, some or all of the following should provide guidelines or assistance. 9.2
Personnel NACE certified
9.3
Recommended Inspection Parameters Refer to NACE RP-02-88 9.3.1
Cleanliness and Profile: Refer to SSPC-VIS1 (reference photos) and NACE TMO175 (sealed steel reference panels NACE RPO287 provides a method of measuring surface profile.
9.3.2
Film thickness a. b.
9.3.3
Hardness: As applicable, refer to the following procedures: a. b. c. d.
9.3.4
Soon after application, wet film "t" measurement should be made. Refer to ASTM D4414. After curing, dry film "t". Refer to SSPC PA2.
ASTM D 2583 ASTM D 2240 ASTM D 3363 Solvent wipe test
Discontinuities a. b.
Linings exceeding 20 mils "t" shall be holiday tested with a high voltage detector (see NACE RPO188). Linings less than 20 mils should be tested with a low voltage (67.5 volts) wet sponge detector.
ITAC API RP-652 Summary, 2007
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SECTION 10 - REPAIR OF TANK BOTTOM LININGS 10.1
General a. b.
10.2
Properly selected/applied liners should provide a service life of 10-20 years. Any bottom mechanical repair should be complete prior to any liner installation or repair.
Evaluation Methods a. b. c. d. e.
Visual Adhesion Audible Lab Testing Holiday Testing
10.3
Evaluation Criteria for Linings
10.4
Evaluating Serviceability of Existing Linings
10.5
Determining the Cause of Lining Degradation Failure
10.6
Lining Repair and Replacement 10.6.1 Localized vs. General Degradation 10.6.2 Spot Repair 10.6.3 Topcoating an Existing Lining 10.6.4 Repair or Topcoating Specifications 10.6.5 Lining Removal Methods
ITAC API RP-652 Summary, 2007
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SECTION 11 – MAXIMIZING SERVICE LIFE 11.1
Lining Material Selection
11.2
Written Specification SECTION 12 - SAFETY
12.2
Tank Entry Permits for tank entry and hot work should be issued and enforced. Follow guidelines for issuing permits and preparing a tank or confined space for entry, as detailed in API Publication 2015.
12.3
Surface Preparation and Lining Application Use respiratory equipment and protective clothing as found in: a. b. c. d. e.
12.4
OSHA Standard for Abrasive Blasting. SSPC PA 3. NACE 6D163. Any relevant federal or state regulation. As required on tank entry permit.
Manufacturer's Material Safety Data Sheets a. b. c.
Indicates the "chemical make-up" that can present health hazards to personnel. MSDS inform about materials so that they can protect themselves and how to respond properly to emergency situations. Purpose of MSDS is to inform personnel of: i. ii. iii. iv. v.
A Material's physical properties which make it hazardous to handle. The type of personal protective equipment needed. First aid treatment necessary ( if exposed). Safe handling under normal conditions and during emergencies such as fires and spills. Appropriate response to accidents.
ITAC API RP-652 Summary, 2007
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API-652 (LINING TANK BOTTOMS) "QUIZ" 1.
Which of the following pertains to or establishes the "dew point"? a. b. c. d.
2.
Difference (in °F) between the relative humidity value and the internal tank air temperature. Difference (in °F) between the internal tank air temperature and the substrate (steel) temperature The temperature at which moisture condenses from the atmosphere. The moisture content value at which adhesion between the liner and the substrate cannot be achieved.
Indicate the most correct definition for "a holiday". a. b. c.
A lamination that develops between coating layers. A discontinuity in a coating film that exposes the metal surface to the environment. Any thin liner area where an additional film "t" layer is required.
3.
, are common examples of aromatic solvents.
4.
A during hot forming operations.
5.
There are five (5) common mechanisms normally associated with internal tank bottom corrosion. List any three (3) of the five (5) causes below.
and
is an oxide layer formed on steel
a. b. c. 6.
Match the following SSPC surface preparation to the metal finish specification, as specified in Section 5. Draw Arrow to Connect. White Metal Finish Near-White Metal Finish
SSPC-SP5 NACE #1 SSPC-SP10 NACE #2
ITAC API RP-652 Summary, 2007
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ITAC 7.
Select the general rule normally followed relative to liner application vs. temperature and humidity restrictions. a. b. c. d.
8.
5°F (3°C) above dew point, with relative humidity below 80% 10°F (5.5°C) above dew point, with relative humidity below 80% Stop application when visually, adhesion and bonding is not being achieved. Any substrate temperature when moisture is visible.
What is the typical range required on anchor pattern (i.e., depth profile) prior to liner installation. Answer:
9.
is a natural or synthetic substance that may be used as a binder in coatings.
10.
When considering the need for an internal lining, make selections from below as some of the more important. A.
B. C. D.
a. Where is corrosion occurring? b. How fast is it proceeding. c. Have there been significant corrosion rates changes. d. What type of corrosion is occurring. e. Have bottom perforations occurred. Sub-items "b", "c" and "d" only. All of the above. Primarily cost and out-of service time frame involved.
ITAC API RP-652 Summary, 2007
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API 652 CODE QUIZ ANSWER KEY 1.
"c"
(Temperature at which moisture condenses from atmosphere. (Paragraph 3.16, Page 3)
2.
"b"
(Discontinuity exposing surface to environment). (Paragraph 3.22, Page 3)
3.
Benzene, Toluene and Xylene. (Paragraph 3.6, Page 3)
4.
Mill Scale
5.
Any of the following:
(Paragraph 3.26, Page 3)
Chemical Corrosion (Paragraph 4.2, Page 4) Concentration Cell Corrosion (Paragraph 4.3, Page 4) Galvanic Cell Corrosion (Paragraph 4.4, Page 4) Erosion Corrosion (Paragraph 4.6, Page 5) Corrosion caused by sulfate-reducing bacteria (Paragraph 4.5, Page 4) Fretting-related Corrosion (Paragraph 4.7, Page 5) 6.
White --------- SSPC-SP5/NACE #1 Near-White ---- SSPS-SP10/NACE #2
7.
"a" (5°F above dew point with relative humidity below 80%) (Paragraph 8.3, Page 11)
8.
1.5 to 4 mils (Paragraph 7.5, Page 10)
9.
Resin (Paragraph 3.30, Page 3)
10.
A - All 5 considerations (Paragraph 4, Page 4)
ITAC API RP-652 Summary, 2007
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Section 6 RP 571 Summary 06
API Recommended Practice 571
Damage Mechanisms Affecting Fixed Equipment in the Refining Industry ITAC General Note: The entire API RP 571 document is not a part of the API 653 Inspector Certification Exam. Only the sections listed here are included on the exam. Color photographs of the corrosion damage are available only when the entire document is downloaded from the internet. The API RP 571 documents which were purchased as hard copies will include black and white photographs only. SECTION 1 - SCOPE 1.2. Scope General guidance as to the most likely damage mechanisms for common alloys used in the refining and petrochemical industry is provided in this recommended practice. SECTION - 2 REFERENCES Outlines the standards, codes and specifications which are cited in the recommended practice. This section is NOT included on the API 653 Certification Exam. SECTION - 3 DEFINITION OF TERMS AND ABBREVIATIONS These terms, symbols and abbreviations are NOT included on the API 653 Certification Exam; however, you are encouraged to become familiar with the terminology of the industry in order to effectively improve communication between you and the many people involved in the inspection process.
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SECTION 4 – General Damage Mechanisms – All Industries 4.1 General Damage mechanisms that are common to a variety of industries including refining and petrochemical, pulp and paper, and fossil utility are covered in this section. 4.2 – Mechanical and Metallurgical Failure Mechanisms 4.2.7 – Brittle Fracture 4.2.7.1 – Description of Damage Brittle fracture is the sudden rapid fracture under stress (residual or applied) where the material exhibits little or no evidence of ductility or plastic deformation. The fracture travels through the part at the speed of sound! Temperature Considerations: 60oF (15 oC – 16oC) Generally, there is no advance notice. 4.2.7.2 – Affected Materials a. Carbon steels and low alloy steels are of prime concern, particularly older steels. b. 400 series stainless steels are also susceptible. 4.2.16 – Mechanical Fatigue 4.2.16.1 – Description of Damage a. Fatigue cracking is a mechanical form of degradation that occurs when a component is exposed to cyclical stresses for an extended period, often resulting in sudden, unexpected failure. b. These stresses can arise from either mechanical loading or thermal cycling and are typically well below the yield strength of the material. 4.2.16.2 – Affected Materials All engineering alloys are subject to fatigue cracking, although the stress levels and number of cycles necessary to cause failure vary by material. ITAC API RP 571 Summary for API 653 Exam, Copyright 2006
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4.3.2 – Atmospheric Corrosion 4.3.2.1 – Description of Damage A form of corrosion that occurs from moisture associated with atmospheric conditions. Marine environments and moist polluted industrial environments with airborne contaminants are most severe. Dry rural environments cause very little corrosion. 4.3.2.3 – Affected Materials a. Carbon Steel b. Low alloy steels c. Copper alloyed aluminum 4.3.3 – Corrosion Under Insulation (CUI) 4.3.3.1 – Description of Damage Corrosion of piping, pressure vessels and structural components resulting from water trapped under insulation or fireproofing. 4.3.3.2 – Affected Materials a. b. c. d.
Carbon steel Low alloy steels 300 series stainless steel Duplex stainless steel
4.3.8 – Microbiological Induced Corrosion (MIC) 4.3.8.1 – Description of Damage A form of corrosion caused by living organisms such as bacteria, algae or fungi. It is often associated with the presence of tubercles or slimy organic substances. 4.3.8.2 – Affected Materials Most common materials of construction, including: a. Carbon steel b. Low allow steel c. 300 series stainless steel d. 400 series stainless steel e. Aluminum f. Copper g. Some nickel based alloys ITAC API RP 571 Summary for API 653 Exam, Copyright 2006
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4.3.9 – Soil Corrosion 4.3.9.1 – Description of Damage The deterioration of metals exposed to soils is referred to as a soil corrosion. 4.3.9.2 – Affected Materials a. Carbon steel b. Cast iron c. Ductile iron 4.3.10 – Caustic Corrosion 4.3.10.1 – Description of Damage Localized corrosion due to the concentration of caustic or Alkaline salts that usually occurs under evaporative or high Heat transfer conditions. However, general corrosion can Also occur depending on alkali or caustic solution strength. 4.3.10.2 – Affected Materials Primarily carbon steel, low alloy steels and 300 Series SS 4.5.1 – Chloride Stress Corrosion Cracking (Cl SCC) 4.5.1.1 – Description of Damage Surface initiated cracks caused by environmental cracking of 300 series stainless steel and some nickel base alloys under the combined action of tensile stress, temperature and an aqueous chloride environment. The presence of dissolved oxygen increases propensity for cracking. 4.5.1.2 – Affected Materials a. All 300 series stainless steels are highly susceptible b. Duplex stainless steels are more resistant c. Nickel base alloys are highly resistant
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4.5.3 – Caustic Stress Corrosion Cracking (Caustic Embrittlement) 4.5.3.1 – Description of Damage Caustic embrittlement is a form of stress corrosion cracking characterized by surface-initiated cracks that occur in piping and equipment exposed to caustic, primarily adjacent to nonPWHT’d welds. 4.5.3.2 – Affected Materials a. Carbon steel b. Low alloy steels c. 300 series stainless steel Nickel base alloys are more resistant.
ITAC API RP 571 Summary for API 653 Exam, Copyright 2006
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SECTION 5 – REFINING INDUSTRY DAMAGE MECHANISMS Damage mechanisms found in the refining environment are discussed in this section. Only Section 5.1.1.11 (Sulfuric Acid Corrosion) has been made a part of the API 653 Certification Exam, and the only item in this section which will be covered in this textbook. 5.1.1.11 – Sulfuric Acid Corrosion 5.1.1.11.1 – Description of Damage Sulfuric acid promotes general and localized corrosion of carbon steel and other alloys. Carbon steel heat affected zones may experience severe corrosion 5.1.1.11.2 – Affected Materials In order of increasing resistance: a. b. c. d. e. f. g.
Carbon steel 316L SS Alloy 20 High silicon cast iron High nickel cast iron Alloy B-2 Alloy C276
The rest of this document is tables and diagrams of process flow diagrams (PFD’s), which are not covered in the API 653 Certification Exam.
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Section 7 577 Summary 06
API RP 577 First Edition - October, 2004 Welding Inspection and Metallurgy
SECTION 1 - SCOPE API RP 577 provides guidance to the API authorized inspector on welding inspection, as encountered with fabrication and repair of refinery and chemical plant equipment and piping. Common welding processes, welding procedures, welder qualifications, metallurgical effects from welding, and inspection techniques are described.
SECTION 2 - REFERENCES SECTION 3 - DEFINITIONS (For the purposes of this standard, the following definitions apply.) 3.1 actual throat: The shortest distance between the weld root and the face of a fillet weld. 3.2 air carbon arc cutting (CAC-A): A carbon arc cutting process variation that removes molten metal with a jet of air. 3.3 arc blow: The deflection of an arc from its normal path because of magnetic forces. 3.4 arc length: The distance from the tip of the welding electrode to the adjacent surface of the weld pool.
3.5 arc strike: A discontinuity resulting from an arc, consisting of any localized remelted metal, heataffected metal, or change in the surface profile of any metal object. 3.6 arc welding (AW): A group of welding processes that produces coalescence of work pieces by heating them with an arc. The processes are used with or without the application of pressure and with or without filler metal. 3.7 autogenous weld: A fusion weld made without filler metal.
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3.8 back-gouging: The removal of weld metal and base metal from the weld root side of a welded joint to facilitate complete fusion and complete joint penetration upon subsequent welding from that side. 3.9 backing: A material or device placed against the backside of the joint, or at both sides of a weld in welding, to support and retain molten weld metal. 3.10 base metal: The metal or alloy that is welded or cut. 3.11 bevel angle: The angle between the bevel of a joint member and a plane perpendicular to the surface of the member. 3.12 burn-through: A non-standard term for excessive visible root reinforcement in a joint welded from one side or a hole through the root bead. Also, a common term used to reflect the act of penetrating a thin component with the welding arc while hot tap welding or in-service welding. 3.13 constant current power supply: An arc welding power source with a volt-ampere relationship yielding a small welding current change from a large arc voltage change. 3.14 constant voltage power supply: An arc welding power source with a volt-ampere relationship yielding a large welding current change from a small voltage change. 3.15 crack: A fracture type discontinuity characterized by a sharp tip and high ratio of length and width to opening displacement. 3.16 defect: A discontinuity or discontinuities that by nature or accumulated effect (for example total crack length) render a part or product unable to meet minimum applicable
acceptance standards or specifications. The term designates rejectability. 3.17 direct current electrode negative (DCEN): The arrangement of direct current arc welding leads in which the electrode is the negative pole and workpiece is the positive pole of the welding arc. Commonly known as straight polarity. 3.18 direct current electrode positive (DCEP): The arrangement of direct current arc welding leads in which the electrode is the positive pole and the workpiece is the negative pole of the welding arc. Commonly known as reverse polarity. 3.19 discontinuity: An interruption of the typical structure of a material, such as a lack of homogeneity in its mechanical, metallurgical or physical characteristics. A discontinuity is not necessarily a defect. 3.20 distortion: The change in shape or dimensions, temporary or permanent, of a part as a result of heating or welding. 3.21 filler metal: The metal or alloy to be added in making a welded joint. 3.22 fillet weld size: For equal leg fillet welds, the leg lengths of the largest isosceles right triangle that can be inscribed within the fillet weld cross section. 3.23 fusion line: A non-standard term for weld interface. 3.24 groove angle: The total included angle of the groove between workpieces.
3.25 heat affected zone (HAZ): The portion of the base metal whose mechanical properties or API Summer Copyright 2004 Page Page7-2 7-2 API 570 570 Summary Copyright Spring, Spring 2004
microstructure have been altered by the heat of welding or thermal cutting.
corner joint, edge joint, lap joint and tjoint.
3.26 heat input: The energy supplied by the welding arc to the workpiece. Heat input is calculated as follows: heat input = (V x i)/60v, where V = voltage, i = amperage, v = weld travel speed (in./min.).
3.36 lack of fusion (LOF): A nonstandard term indicating a weld discontinuity in which fusion did not occur between weld metal and fusion faces or adjoining weld beads.
3.27 hot cracking: Cracking formed at temperatures near the completion of solidification. 3.28 inclusion: Entrapped foreign solid material, such as slag, flux, tungsten or oxide. 3.29 incomplete fusion: A weld discontinuity in which complete coalescence did not occur between weld metal and fusion faces or adjoining weld beads. 3.30 incomplete joint penetration: A joint root condition in a groove weld in which weld metal does not extend through the joint thickness. 3.31 inspector: An individual who is qualified and certified to perform inspections under the proper inspection code or who holds a valid and current National Board Commission.
3.37 lamellar tear: A subsurface terrace and step-like crack in the base metal with a basic orientation parallel to the wrought surface caused by tensile stresses in the throughthickness direction of the base metal weakened by the presence of small dispersed, planar shaped, nonmetallic inclusions parallel to the metal surface. 3.38 lamination: A type of discontinuity with separation or weakness generally aligned parallel to the worked surface of a metal. 3.39 linear discontinuity: A discontinuity with a length that is substantially greater than its width. 3.40 longitudinal crack: A crack with its major axis orientation approximately parallel to the weld axis.
3.32 interpass temperature, welding: In multipass weld, the temperature of the weld area between weld passes.
3.41 nondestructive examination (NDE): The act of determining the suitability of some material or component for its intended purpose using techniques that do not affect its serviceability.
3.33 IQI: Image quality indicator. “Penetrameter” is another common term for IQI.
3.42 overlap: The protrusion of weld metal beyond the weld toe or weld root.
3.34 joint penetration: The distance the weld metal extends from the weld face into a joint, exclusive of weld reinforcement.
3.43 oxyacetylene cutting (OFC-A): An oxygen gas cutting process variation that uses acetylene as the fuel gas.
3.35 joint type: A weld joint classification based on five basic joint configurations such as a butt joint,
3.44 PMI (Positive Materials Identification): Any physical evaluation or test of a material ITAC API570 570Summer SummaryCopyright CopyrightSpring, Spring2004 2004 API
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(electrode, wire, flux, weld deposit, base metal, etc.), which has been or will be placed into service, to demonstrate it is consistent with the selected or specified alloy material designated by the owner/user. These evaluations or tests may provide either qualitative or quantitative information that is sufficient to verify the nominal alloy composition. 3.45 peening: The mechanical working of metals using impact blows. 3.46 penetrameter: Old terminology for IQI still in use today but not recognized by the codes and standards. 3.47 porosity: Cavity-type discontinuities formed by gas entrapment during solidification or in thermal spray deposit. 3.48 preheat: Metal temperature value achieved in a base metal or substrate prior to initiating the thermal operations. 3.49 recordable indication: Recording on a data sheet of an indication or condition that does not necessarily exceed the rejection criteria but in terms of code, contract or procedure will be documented. 3.50 reportable indication: Recording on a data sheet of an indication that exceeds the reject flaw size criteria and needs not only documentation, but also notification to the appropriate authority to be corrected. All reportable indications are recordable indications but not vice-versa. 3.51 root face: The portion of the groove face within the joint root. 3.52 root opening: A separation at the joint root between the workpieces.
3.53 shielding gas: Protective gas used to prevent or reduce atmospheric contamination. 3.54 slag: A nonmetallic product resulting from the mutual dissolution of flux and nonmetallic impurities in some welding and brazing processes. 3.55 slag inclusion: A discontinuity consisting of slag entrapped in the weld metal or at the weld interface. 3.56 spatter: The metal particles expelled during fusion welding that do not form a part of the weld. 3.57 tack weld: A weld made to hold the parts of a weldment in proper alignment until the final welds are made. 3.58 throat theoretical: The distance from the beginning of the joint root perpendicular to the hypotenuse of the largest right triangle that can be inscribed within the cross-section of a fillet weld. This dimension is based on the assumption that the root opening is equal to zero. 3.59 transverse crack: A crack with its major axis oriented approximately perpendicular to the weld axis. 3.60 travel angle: The angle less than 90 degrees between the electrode axis and a line perpendicular to the weld axis, in a plane determined by the electrode axis and the weld axis. 3.61 tungsten inclusion: A discontinuity consisting of tungsten entrapped in weld metal. 3.62 undercut: A groove melted into the base metal adjacent to the weld toe or weld root and left unfilled by weld metal. 3.63 underfill: A condition in which the weld joint is incompletely filled 570 Summary Summer Copyright Spring, 2004 2004 Page Page7-4 7-4 ITAC API API 570 Copyright Spring
when compared to the intended design. 3.64 welder certification: Written verification that a welder has produced welds meeting a prescribed standard of welder performance. 3.65 welding: A joining process that produces coalescence of base metals by heating them to the welding temperature, with or without the application of pressure or by the application of pressure alone, and with or without the use of filler metal. 3.66 welding engineer: An individual who holds an engineering degree and is knowledgeable and experienced in the engineering disciplines associated with welding. 3.67 weldment: An assembly whose component parts are joined by welding. 3.68 weld joint: The junction of members or the edges of members which are to be joined or have been joined by welding. 3.69 weld reinforcement: Weld metal in excess of the quantity required to fill a joint. 3.70 weld toe: The junction of the weld face and the base metal.
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SECTION 4: 4.1
WELDING INSPECTION
GENERAL This section focuses on the tasks that are not only considered the responsibility of the inspection personnel, but also other concerned parties who will design, examine or perform welding.
4.2
TASKS PRIOR TO WELDING These crucial steps are necessary to avoid the many welding problems which can occur during or after the welding process. 4.2.1
Drawings, Codes and Standards Review the drawings, standards, codes and specifications to ensure the requirements for the weldment are understood, as well as to identify any inconsistencies.
4.2.2
Weldment Requirements Review requirements for the weldment with the personnel involved with executing the work
4.2.3
Procedures and Qualification Records Review the WPS(s) and welder performance qualification record(s) (WPQ) to assure they are acceptable for the work.
4.2.4
NDE Information Confirm the NDE examiner(s), NDE procedure(s) and NDE equipment of the inspection organization are acceptable for the work.
4.2.5
Welding Equipment and Instruments Confirm welding equipment and instruments are calibrated and operate properly.
4.2.6
Heat Treatment and Pressure Testing Confirm heat treatment and pressure testing procedures and associated equipment are acceptable.
4.2.7
Materials Ensure all filler metals, base materials and backing ring materials are properly marked and identified and, if required, perform PMI to verify the material composition. API 570 Summer Copyright Spring, 2004 Page 7-6 ITAC API 570 Summary Copyright Spring 2004 Page 7-6
4.2.8
Weld Preparation Confirm weld preparation, joint fit-up, and dimensions are acceptable and correct.
4.2.9
Preheat Confirm the preheat equipment and temperature.
4.2.10 Welding Consumables Confirm electrode, filler wire, fluxes, and inert gases are as specified and acceptable. 4.3
TASKS DURING WELDING OPERATIONS Welding inspection during welding operations should include audit parameters to verify the welding is performed to the procedures. 4.3.1
Quality Assurance Establish a quality assurance and quality control umbrella with the welding organization.
4.3.2
Welding Parameters and Techniques Confirm welding parameters and techniques are supported by the WPS and WPQ.
4.3.3
Weldment Examination Complete physical checks, visual examination and in-process NDE
4.4
TASKS UPON COMPLETION OF WELDING Final tasks upon completion of the weldment and work should include those that assure final weld quality before placing the weldment in service. 4.4.1
Appearance and Finish Verify post-weld acceptance, appearance and finishing of the welded joints.
4.4.2
NDE Review Verify NDE is performed at selected locations and review examiner’s findings.
4.4.3
Post-weld Heat Treatment Verify post-weld heat treatment is performed to the procedure and produces acceptable results. ITAC API RP 577 Summary for API 653 Exam, Copyright Spring 2006 Page 7-7
4.4.4
Pressure Testing Verify pressure test is performed to the procedure.
4.4.5
Documentation Audit Perform a final audit of the inspection dossier to identify inaccuracies and incomplete information.
4.5
NON-CONFORMANCES AND DEFECTS At any time during the welding inspection, if defects or non-conformances to the specification are identified, they should be brought to the attention of those responsible for the work or corrected before welding proceeds further.
4.6
NDE EXAMINER CERTIFICATION The referencing codes or standards may require the examiner to be qualified in accordance with a specific code and certified as meeting the requirements. They also require the employer to develop and establish a written practice or procedure that details the employer’s requirements for certification of inspection personnel.
4.7
SAFETY PRECAUTIONS Inspectors should be aware of the hazards associated with welding and take appropriate steps to prevent injury while performing inspection tasks. At a minimum, the site’s safety rules and regulations should be reviewed as applicable to welding operations.
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SECTION 5 – WELDING PROCESSES 5.1
GENERAL The inspector should understand the basic arc welding processes most frequently used in the fabrication and repair of refinery and chemical process equipment. These processes include: a. b. c. d. e. f.
5.2
Shielded metal arc welding (SMAW) Gas tungsten arc welding (GTAW) Gas metal arc welding (GMAW) Flux cored arc welding (FCAW) Submerged arc welding (SAW) Stud arc welding (SW)
SHIELDED METAL ARC WELDING (SMAW) a. b. c.
e.
Most widely used of the various arc welding processes. Uses an arc between a covered electrode and the weld pool. Employs the heat of the arc coming from the tip of a consumable covered electrode, to melt the base metal. Shielding is provided from the decomposition of the electrode covering, without the application of pressure and with filler metal from the electrode Either alternating current (ac) or direct current (dc) may be employed.
5.2.1
Electrode Covering
d.
Depending on the type of electrode being used, the covering performs one or more of the following functions: a. b. c. d. e. 5.2.2
Provides a gas to shield the arc and prevent excessive atmospheric contamination of the molten filler metal. Provides scavengers, deoxidizers, and fluxing agents to cleanse the weld and prevent excessive grain growth in the weld metal. Establishes the electrical characteristics of the electrode. Provides a slag blanket to protect the hot weld metal from the air and enhances the mechanical properties, bead shape, and surface cleanliness of the weld metal. Provides a means of adding alloying elements to change the mechanical properties of the weld metal.
Advantages of SMAW a. b. c. d. e.
Equipment is relatively simple, inexpensive, and portable. Can be used in areas of limited access. Less sensitive to wind and draft than other processes. Used with most common metals and alloys High quality welds. ITAC API RP 577 Summary for API 653 Exam, Copyright Spring 2006 Page 7-9
5.2.3
Limitations of SMAW a. b. c.
5.3
Deposition rates are lower than for other processes. Slag usually must be removed at stops and starts, and before depositing a weld bead adjacent to or onto a previously deposited weld bead. Electrode storage.
GAS TUNGSTEN ARC WELDING (GTAW) a. b. c. d. • • • • • • • • • • • • 5.3.1
Uses an arc between a non-consumable tungsten electrode and the weld pool. Used with shielding gas and without the application of pressure. Used with or without the addition of filler metal (Autogenous). The CC type power supply can be used with either dc or ac. Injection points Deadlegs Corrosion under insulation (CUI) Soil-to-air (S/A) interfaces Service specific and localized corrosion Erosion and corrosion/erosion Environmental cracking Corrosion beneath linings and deposits Fatigue cracking Creep cracking Brittle fracture Freeze damage Advantages of GTAW a. b. c. d. e. f. g.
5.3.2
Produces high purity welds. Little post-weld cleaning is required. Allows for excellent control of root pass weld penetration Can be used for autogenous welds (no filler metal). Good for thin metals Good appearance Mechanization potential
Limitations of GTAW a. b. c. d.
Relatively slow deposition rate Low tolerance for contaminants Difficult to shield the weld zone in drafty environments Two-handed process
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5.4
GAS METAL ARC WELDING (GMAW) a. b. c. d. e.
Uses an arc between continuous filler metal electrode and the weld pool. Used with shielding from an externally supplied gas and without application of pressure. Can be operated in semiautomatic, machine or automatic modes. Employs a constant voltage (CV) power supply Uses short-circuiting, globular or spray methods to transfer metal from the electrode to the workpiece. The type of transfer is determined by these most influential factors: i. ii. iii. iv. v.
5.4.1
Short Circuiting Transfer (GMAW-S) a. b.
Encompasses the lowest range of welding currents and electrode diameters. Produces a fast freezing weld pool that is generally suited for: i. ii. iii.
c.
5.4.2
Joining thin sections Out-of-position Root pass
With fast-freezing nature of the process, comes the potential for lack of sidewall fusion when welding thick-wall equipment or a nozzle attachment.
Globular Transfer a. b. c. d.
5.4.3
Magnitude and type of welding current Electrode diameter Electrode composition Electrode extension Shielding gas
Encompasses relatively low current (below 250 A). Characterized by a drop size with a diameter greater than that of the electrode Generally limited to the flat position. Can produce spatter.
Spray Transfer a. b. c.
Highly directed stream of discrete drops that are accelerated by arc forces. Spatter is negligible May be difficult to apply to thin sheets. (Thickness limitations of the spray arc have been overcome by the use of pulsed GMAW, in which the current is pulsed to obtain the advantage of spray transfer). ITAC API RP 577 Summary for API 653 Exam, Copyright Spring 2006 Page 7-11
5.4.4
Advantages of GMAW a. b. c. d. e. f.
5.4.5
Limitations of GMAW a. b. c. d. e. f.
5.5
Only consumable electrode process that can weld most commercial metals and alloys. High productivity – deposition rates are significantly higher. No slag to remove. Clean process Continuous feed Lowest hydrogen potential of all processes
Equipment is more complex and more costly. Equipment is less portable and usually limited to shop welding. Unsuitable for windy conditions. Weld is more susceptible to lack of fusion. Little tolerance for contamination. Consumables.
FLUX CORED ARC WELDING (FCAW) a. b. c. d. e.
Process uses an arc between continuous tubular filler metal electrode and the weld pool. Used with shielding gas from a flux contained within the tubular electrode. Can be used with or without additional shielding from an externally supplied gas. Normally a semiautomatic process. Use depends on: i. ii. iii.
type of electrodes available mechanical property requirements of the welded joints joint designs and fit-up
f.
Recommended power source is the dc constant-voltage type.
5.5.1
Advantages of FCAW a. b. c. d. e. f.
5.5.2
Metallurgical benefits from the flux. Slag supports and forms the weld bead. High deposition of weld metal. Suitable for field work since shielding is produced at the surface giving better protection against drafts. Tolerates contamination. Deep penetration.
Limitations of FCAW a. b. c. d.
Equipment is complex, costly and less portable. Heavy fumes require exhaust equipment. Slag removal between passes. Backing material is required for root pass welding. ITAC API RP 577 Summary for API 653 Exam, Copyright Spring 2006 Page 7-12
5.6
SUBMERGED ARC WELDING (SAW) a. b. c. d.
Uses an arc or arcs between a flux covered bare metal electrode(s) and the weld pool. The arc and molten metal are shielded by a blanket of granular flux, supplied through the welding nozzle from a hopper. Process is used without pressure and filler metal from the electrode and sometimes from a supplemental source (welding rod, flux or metal granules). Can be applied in three different modes: i. ii. iii.
e. f.
Can use either a CV or CC power supply Used extensively in ship pressure vessel fabrication and pipe manufacturing.
5.6.1
Advantages of SAW a. b. c. d. e. f.
5.6.2
Very high deposition rate. Repeatable high quality welds for large weldments and repetitive short welds. Deep penetration. Good for overlay. Hand-held process. High operator appeal.
Limitations of SAW a. b. c. d. e. f.
5.7
semiautomatic automatic machine
Requires high amperage at 100% duty cycle. Arc not visible, making it harder to control. Flat or horizontal fillets only. Extensive set up time. Needs positioning equipment. Slag removal.
STUD ARC WELDING (SW) a. b. c. d. e. f. g. h.
Uses an arc between a metal stud and the work piece. Once the surfaces of the parts are properly heated, they are brought into contact by pressure. Shielding gas or flux may or may not be used. Process may be fully automatic or semiautomatic. Stud gun holds the tip of the stud against the work. Direct current is normally used for SW, with the stud gun connected to the negative terminal (DCEN) The power source is a CC type. Predominantly limited to welding insulation and refractory support pins to tanks, pressure vessels and heater casing. ITAC API RP 577 Summary for API 653 Exam, Copyright Spring 2006 Page 7-13
5.7.1
Advantages of SW a. b. c. d. e.
5.7.2
High productivity Considered an all-position process Simple Repetitive Automatic stud feeding (option)
Limitations of SW a. b. c. d.
Primarily suitable for only carbon and low-alloy steels. Specialized to a few applications. Needs clean surface. Equipment malfunctions.
SECTION 6 – WELDING PROCEDURES (See ITAC Chapter 9 for additional information) This section will be discussed during the ASME Section IX presentation. Anyone who is not familiar with welding procedures should review this section at length.
SECTION 7 – WELDING MATERIALS (See ITAC Chapter 9 for additional information) This section will be discussed during the ASME Section IX presentation. Anyone who is not familiar with welding materials should review this section at length.
SECTION 8 – WELDER QUALIFICATION (See ITAC Chapter 9 for additional information) This section will be discussed during the ASME Section IX presentation. Anyone who is not familiar with welder qualifications should review this section at length.
SECTION 9 – NONDESTRUCTIVE EXAMINATION (See ITAC Chapter 8 for additional information) This section will be discussed during the ASME Section V presentation. Anyone who is not familiar with NDE methods should review this section at length. ITAC API RP 577 Summary for API 653 Exam, Copyright Spring 2006 Page 7-14
SECTION 10 - METALLURGY (See ITAC Chapter 10 for additional information) This section contains a very basic discussion of welding metallurgy, and a review of this section will give you a general overview of the subject. It will not, however, make you proficient in metallurgy. Additional study is a must.
SECTION 11 – REFINERY AND PETROCHEMICAL PLANT WELDING ISSUES 11.1
GENERAL This section provides details of specific welding issues encountered by the inspector in refineries and petrochemical plants.
11.2
HOT TAPPING AND IN-SERVICE WELDING Prior to performing this work, a detailed written plan should be developed and reviewed. 11.2.1 Electrode Considerations 1.
Hot tap and in-service welding operations should be carried out only with low-hydrogen consumables and electrodes (e.g., E7016, E7018 and E7048).
2.
Extra-low hydrogen consumables, such as Exxxx-H4, should be used for welding carbon steels with CE greater than 0.43% or where there is potential for hydrogen assisted cracking (HAC) such as cold worked pieces, high strength and highly constrained areas.
3.
Cellulosic type electrodes (e.g., E6010, E6011 or E7010) may be used for root and hot passes. (a)
Advantages of cellulosic electrodes: (i) (ii)
(b)
easy to operate. provide improved control over the welding arc.
Limitations of cellulosic electrodes: (i) (ii)
increased risk of HAC and burn-through. Higher risk of hydrogen assisted cracking (HAC).
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11.2.2 Flow Rates Under most conditions, some product flow inside the material being welded is advantageous. 11.2.3 Other Considerations Avoid “weave” beads to reduce heat input. 11.2.4 Inspection a. b.
UT for laminations should be performed before welding. VT, PT and/or MT can be performed on completed welds.
ITAC API RP 577 Summary for API 653 Exam, Copyright Spring 2006 Page 7-16
APPENDIX A – TERMINOLOGY AND SYMBOLS A.1
WELD JOINT TYPES Five basic joints: a.
Butt: A joint between two members aligned approximately in the same plane.
Applicable Welds: Bevel-Groove
U-Groove
Flare-Bevel-Groove
V-Groove
Flare-V-Groove
Edge Weld
J-Groove
Scarf (for braze joint)
Square-Groove
b.
Corner: A joint between two members located approximately at right angles to each other in the form of an L.
Applicable Welds: Filet
Edge Weld
Bevel-Groove
Plug
Flare-Bevel-Groove
Slot
Flare-V-Groove
Spot
J-Groove Square-Groove U-Groove
Seam Projection V-Groove
ITAC API RP 577 Summary for API 653 Exam, Copyright Spring 2006 Page 7-17
c.
Tee: A joint between two members located approximately at right angles to each other in the form of a T.
Applicable Welds:
d.
Lap: A joint between two overlapping members in parallel planes.
Applicable Welds: Fillet Bevel-Groove Flare-V-Groove J-Groove Square-Groove
Slot Spot Seam Projection *Braze
Plug
ITAC API RP 577 Summary for API 653 Exam, Copyright Spring 2006 Page 7-18
e.
Edge: A joint between two or more parallel or nearly parallel members.
Applicable Welds: Bevel-Groove
U-Groove
Flare-Bevel-Groove
V-Groove
Flare-V-Groove
Edge
J-Groove
Seam
Square-Groove
ITAC API RP 577 Summary for API 653 Exam, Copyright Spring 2006 Page 7-19
A.2
WELD SYMBOLS Engineering and construction drawings often use standard symbols to represent weld details. Figure A-2 – Symbols for Various Weld Joints
Note: The reference line is shown dashed for illustrative purposes.
Figure A-3 – Supplementary Symbols for Welds
ITAC API RP 577 Summary for API 653 Exam, Copyright Spring 2006 Page 7-20
Figure A-4 – Standard Weld Symbols
A.3
WELD JOINT NOMENCLATURE Standard terminology applies to the various components of a weld joint. Figure A-5 – Groove Weld Nomenclature
ITAC API RP 577 Summary for API 653 Exam, Copyright Spring 2006 Page 7-21
A.4
ELECTRODE IDENTIFICATION The AWS specification and classification system allows selection of an electrode, which will provide a weld metal with specific mechanical properties and alloy composition. Figure A-6 – SMAW Welding Electrode Identification System
Figure A-7 – GMAW/GTAW welding Electrode Identification System
Figure A-8 – FCAW Welding Electrode Identification System
ITAC API RP 577 Summary for API 653 Exam, Copyright Spring 2006 Page 7-22
Figure A-9 – SAW Welding Electrode Identification System
APPENDIX B – ACTIONS TO ADDRESS IMPROPERLY MADE PRODUCTION WELDS No comment APPENDIX C – WELDING PROCEDURE REVIEW This subject matter is covered in the review of ASME Section IX, but is an excellent source of reference material for those who do not have experience with welding procedures. APPENDIX D – GUIDE TO COMMON FILLER METAL SELECTION No comment
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Section 8 NDE Sum-2007
API 653 Nondestructive Examination API Paragraph 12.1.1.1 Nondestructive Examination procedures, qualifications and acceptance criteria shall be prepared for visual, magnetic particle, liquid penetrant, ultrasonic, and radiographic methods in accordance with API Standard 650 and the supplemental requirements given herein. API 653 Paragraph 12.1.1.2 Personnel performing nondestructive examinations shall be qualified in accordance with API 650 and the supplemental requirements given herein. API 653 Paragraph 12.1.1.3 Acceptance Criteria is based on API 650 and supplemental requirements of API 653. API 653 Paragraph 12.1.1.5 New Appendix G is introduced. The requirements for MFL, procedures, operator qualifications, training and equipment calibration is listed in this appendix. API 653 uses API 650 requirements for nondestructive testing procedures and personnel certification. The American Society for Nondestructive Testing, Inc. Recommended Practice SNT-TC1A is recognized for technician qualifications in some NDE techniques. SNT-TC-1A is a document that outlines requirements for Personnel Qualification and Certification in Nondestructive Testing, the main items listed are: a. b. c. d.
Work Experience Training Education Testing
In order to qualify as an ASNT Level II, Radiographers must have: a. b. c. d.
12 Months Job Experience 79 Hours Formal Training High School Graduation Level II Exam, General, Specific and Practical
ITAC NDE Summary, 2007
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In order to qualify as an ASNT Level II, Ultrasonic Technicians must have: a. b. c. d.
12 Months Job Experience 80 Hours Formal Training High School Graduation Level II Exam, General, Specific and Practical API 650 does not require MT or PT Technicians to be certified to ASNT-SNT-TC-1A.
Nondestructive Examination API 650 Magnetic Particle Method
MT Principles of Operation Basically, an object or localized area is magnetized through the use of AC or DC current. Once the area is magnetized lines of flux are formed, see above. Dry iron powder, or iron powder held in suspension is added to the surface of the test piece. Any interruption in the lines of flux will create an indication which can be evaluated. The process may be used on any material that is ferromagnetic. This method of NDE can be used in visible light or with special powders, under black light. Surface discontinues are the most commonly detected indications using this process.
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API 653 requirements API 653 directs the user to API 650 Paragraph 6.2.1 - 6.2.3 When magnetic particle examination is specified, the method of examination shall be in accordance with the ASME Boiler and Pressure Vessel Code, Section V, Nondestructive Examination, Article 7. API 650 Paragraph 6.2.2 Magnetic particle examination shall be performed in accordance with a written procedure that is certified by the manufacturer to be in compliance with the applicable requirements of Section V, of the ASME Code. API 650 Paragraph 6.2.3 No ASNT Certification Required, Manufacturer Determined Magnetic Particle Method Acceptance Standards per API 650 API 650 Paragraph 6.2.4 Acceptance standards and removal and repair of defects shall be per Section VIII, Appendix 6, Paragraphs 6-3 and 6-4, of the ASME Code. ASME Section VIII, Appendix 6, Paragraph 6-3 Definition of indication. Must be larger than 1/16”. ASME Section VIII, Appendix 6, Paragraph 6-4 Acceptance Standards All surfaces to be examined shall be free of: a. b. c.
relevant linear indications; relevant rounded indications greater than 3/16” four or more relevant rounded indications in line separated by 1/16” or less, edge to edge.
API 650 Paragraph 6.2.4 Acceptance standards and removal and repair of defects shall be per Section VIII, Appendix 6, Paragraphs 6-3 and 6-4, of the ASME Code. ASME Section VIII, Appendix 6, Paragraph 6-3 Definition of indication. Must be larger than 1/16”.
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ASME Section VIII, Appendix 6, Paragraph 6-4 Acceptance Standards All surfaces to be examined shall be free of: a. b. c.
relevant linear indications; relevant rounded indications greater than 3/16” four or more relevant rounded indications in line separated by 1/16” or less, edge to edge.
Study Notes:
Page Number:
Standard/Code
Calibration requirements
_____________
________________
Yoke weight requirements, both AC and DC
_____________
________________
General MT procedure requirements
_____________
________________
Know where to find:
ITAC NDE Summary, 2007
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Nondestructive Examination API 650 Liquid Penetrant Method
PT Principles of Operation Penetrant testing is a family of testing that can be divided in to two major groups, visible light and fluorescent or “Black Light” detectable groups. the basic steps of the operation can be seen above. Step 1 the test piece must be cleaned. Step two the penetrant is applied, a dwell time or soaking time waited. Step three the excess penetrant is removed. Step four the developer applied. Step five the part is inspected, any indication is evaluated. Step six the part is post cleaned. This inspection technique relays on the penetrant being pulled in to all surface irregularities by capillary action. When the developer is applied the penetrant is blotted back to the surface making the irregularities visible. The irregularities are then evaluated into three groups, false indications, commonly called handling marks, nonrelevant indications and defects. The defects are evaluated to a given standard for acceptance. This process will detect:
Surface defects only! ITAC NDE Summary, 2007
Page 8-5
Nondestructive Examination API 650 Liquid Penetrant Method API 650 Paragraph 6.4.1 When liquid penetrant examination is specified, the method of examination shall be in accordance with the ASME Boiler and Pressure Vessel Code, Section V, "Nondestructive Examination,” Article 6 API 650 Paragraph 6.4.2 Liquid Penetrant examination shall be performed in accordance with a written procedure that is certified by the manufacturer to be in compliance with the applicable requirements of Section V, of the ASME Code. API 650 Paragraph 6.4.3 No ASNT Certification Required, Manufacturer Determined API 650 Paragraph 6.4.4 Acceptance standards and removal and repair of defects shall be per Section VIII, Division 1, Appendix 8, Paragraphs 8-3 , 8-4 and 8-5, of the ASME Code ASME Section VIII Division 1 Liquid Penetrant Examination - Acceptability Appendix 8 paragraph 8-3 Evaluation of Indications An indication is the evidence of a mechanical imperfection. Only indications with major dimensions greater than 1/16 in. shall be considered relevant. a. b. c,
A linear indication is one having a length greater than three times the width. A rounded indication is one of circular or elliptical shape with the length equal to or less than three times the width. Any questionable or doubtful indications shall be reexamined to determine whether or not they are relevant.
Appendix 8 paragraph 8-4 Acceptance Standards All surfaces shall be free of : a. b. c.
relevant linear indications relevant rounded indications greater than 3/16” four or more relevant rounded indications separated by 1/16”
Appendix 8 paragraph 8-5 Repair Requirements ITAC NDE Summary, 2007
Page 8-6
Nondestructive Examination API 650 Liquid Penetrant Method Study Notes Read ASME Section V, Article 6
Study Notes:
Page Number:
Standard/Code
Test temperatures
_____________
_______________
Surface temperatures
_____________
_______________
General PT procedure requirements
_____________
_______________
Know where to find:
ITAC NDE Summary, 2007
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Nondestructive Examination API 650 Ultrasonic Method (Weld Quality)
API 650 Paragraph 6.3.1 Introduction of the new Appendix U. This appendix sets requirements for UT inspection when performed in lieu of radiography. API 650 Paragraph 6.3.2.2 (Ultrasonic requirements not in lieu of radiography) When ultrasonic examination is specified, the method of examination shall be in accordance with the ASME Boiler and Pressure Vessel Code, Section V, "Nondestructive Examination," Article 5. API 650 Paragraph 6.3.2.3 Ultrasonic examination shall be performed in accordance with a written procedure that is certified by the manufacturer to be in compliance with the applicable requirements of Section V, of the ASME Code. API 650 Paragraph 6.3.2.4 Examiners performing ultrasonic examinations under this section shall be qualified and certified by the manufacturers as meeting the requirements of certification as generally outlined in Level II or Level III of ASNT Recommended Practice SNT-TC-1A (including applicable supplements).
Note: "Acceptance standards shall be agreed upon by the purchaser and the manufacturer." API 650 Paragraph 6.3.2.5 The API 653 Effectivity Sheet has listed ASME Section V, Article 23 (Section SE-797 only). This section deals with “Standard Practice for Measuring Thickness by Manual Ultrasonic Pulse-Echo Contact Method”. The section includes the general procedure requirements for thickness readings. ITAC NDE Summary, 2007
Page 8-8
Nondestructive Examination API 650 Radiographic Examination
IQI
Shim 17
Weld
1
1 ASTM B
2
API 650 Paragraph 6.1.3.1 Except as modified in this section, the radiographic examination method employed shall be in accordance with Section V, Nondestructive Examination," Article 2., of the ASME Code. API 650 Paragraph 6.1.3.2 Personnel who perform and evaluate radiographic examinations according to this section shall be qualified and certified by the manufacturers as meeting the requirements of certification as generally outlined in Level II or Level III of ASNT Recommended Practice SNT-TC-1A (including applicable supplements). API 650 Paragraph 6.1.3.3 The requirements of T-285 in Section V, Article 2, of the ASME Code are to be used only as a guide. Final acceptance of radiographs shall be based on whether the prescribed penetrameter image and the specified hole can be seen.
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Radiographic Examination Acceptability API 650 Paragraph 6.1.5 The acceptability of welds examined by radiography shall be judged by the standards in Section VIII, Division I, Paragraph UW-51(b), of the ASME Code. UW-51 Radiographic and Radioscopic Examination of Welded Joints (b) This section requires indications shown on the radiographs to be repaired. The repairs may be radiographed or optionally, examined by ultrasonic examination. Indications that are unacceptable: Any crack Zone of incomplete fusion Zone of incomplete penetration Any other elongated indication which is longer than: 1/4 in for t up to 3/4 in 1/3 t for t from 3/4 in to 2 1/4 in 3/4 in for t over 2 1/4 in UW-51 Radiographic and Radioscopic Examination of Welded Joints (subparagraph 3) Any group of aligned indications that have an aggregate length between the successive imperfections exceeds 6L where L is the length of the longest imperfection in the group. Rounded indications in excess of that specified by the acceptance standards given in Appendix 4.
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Nondestructive Examination API 650 Radiographic Examination Study Notes
Read ASME Section V, Article 2
Study Notes:
Page Number:
Standard/Code
Backscatter acceptability
_____________
________________
Geometric Unsharpness
_____________
________________
IQI information
_____________
________________
Density
_____________
________________
Location Markers
_____________
________________
General RT procedure requirements
_____________
________________
Know where to find:
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Section 9 ASME IX Summary-07
API 653 ASME Section IX API 653 - Section 11 - Welding 11.1.1 Welding procedure specifications (WPS) and welders and welding operators shall be qualified in accordance with Section IX of the ASME Code. This includes welding procedure qualification records (PQR). ASME Section IX is a document that outlines the requirements for welding procedures and welder qualifications. Other organizations that have the requirements for procedures are AWS (American Welding Society) and API (American Petroleum Institute) (API 1104). While both organizations have excellent rules, the only origination required by API 653 is ASME Section IX. A welding procedure shows compatibility of: a. b. c. d.
Base metals Filler metals Processes Technique
The general approaches to procedure qualification is usually in one of two forms: a.
Prequalified procedures: These are AWS welding procedures used only for structural welding and do not require testing. The user is limited to specific weld joints and specific weld processes (see AWS D 1.1).
b.
Procedure qualification testing: These are API and ASME requirements. Both require actual welding to be performed and destructively tested.
ASME procedure qualification testing uses a listing of essential variables in the creation of weld procedures. Essential variables are those in which a change is considered to affect the mechanical properties of the weldment, and shall require requalification of the WPS, ASME IX Paragraph QW - 251.2. Under ASME rules the welding procedure begins with the creation of the WPS. This information is taken from ASME IX and outlines the ranges of materials, electrodes and other general aspects. Then the PQR is created, performed and tested and used as proof for the WPS. The WPS can have many supporting PQRs.
Locations of weld specimens from plate procedure qualification. ITAC ASME IX Summary, 2007
Page 9-1
Locations of weld specimens from pipe procedure qualification. ITAC ASME IX Summary, 2007
Page 9-2
ITAC ASME IX Summary, 2007
Page 9-3
Weld procedure specimens, guided bends are also used for welder qualification tests.
Square
Tensile Specimens
Round
Guided Bends Face
Root
ITAC ASME IX Summary, 2007
Side
Page 9-4
The tests commonly required by ASME Section IX are: a. b.
Tensile Bends 1. 2. 3.
Face Root Side
Table QW -451 is the Procedure qualification thickness limits and test specimens requirements. Each groove weld must pass tension tests and transverse bend tests. This table is where the requirements for testing are listed.. After the procedure qualification testing the Welding Inspector must check production welding to ensure welds are being made in compliance with the approved and tested weld procedure. Remember the weld procedure is proof that the weld can be successfully made. The general sequence for procedure qualification testing is as follows: •
Select welding variables (write the WPS and PQR)
•
Check equipment and materials for suitability
•
Monitor weld joint fit-up as well as actual welding, recording all important variables and observations
•
Select, identify and remove required test specimens
•
Test and evaluate specimens
•
Review test results for compliance with applicable code requirements
•
Release approved procedure for production
•
Qualify individual welders in accordance with this procedure
•
Monitor production welding for procedure compliance
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QW-482 SUGGESTED FORMAT FOR WELDING PROCEDURE SPECIFICATIONS (WPS) (See QW-200.1, Section IX, ASME Boiler and Pressure Vessel Code) Company Name: Welding Procedure Specification No. Revision No. Welding Process(es):
By: Supporting PQR No.(s)
Date: Date: Type(s):
Automatic, Manual, Machine, or Semi-Auto
JOINTS (QW-402) Joint Design Backing (Yes) Backing Material (Type)
Details (No) (Refer to both backing and retainers)
Metal Nonmetalic
Nonfusing Metal Other
Sketches, Production Drawings, Weld Symbols or Written Description should show the general arrangement of the parts to be welded. Where applicable, the root spacing and the details of weld groove may be specified. (At the option of the Mfgr., sketches may be attached to illustrate joint design, weld layers and bead sequence, e.g., for notch toughness procedures, for multiple process procedures, etc.)
*BASE METALS (QW-403) P-No. Group No. OR Specification type and grade to Specification type and grade OR Chem. Analysis and Mech. Prop. to Chem. Analysis and Mech. Prop. Thickness Range: Base Metal: Groove Other:
to P-No.
Group No.
Fillet
*FILLER METALS (QW-404) Spec. No. (SFA) AWS No. (Class) F-No. A-No. Size of Filler Metals Weld Metal Thickness Range: Groove Fillet Electrode-Flux (Class) Flux Trade Name Consumable Insert Other *Each base metal-filler metal combination should be recorded individually
ITAC ASME IX Summary, 2007
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QW-482 (Back) WPS No.
POSITIONS (QW-405)
Rev.
POSTWELD HEAT TREATMENT (QW-407)
Position(s) of Groove Welding Progression: Up Position(s) of Fillet
Temperature Range Time Range
Down
GAS (QW-408) PREHEAT (QW-406)
Percent Composition
Preheat Temp. - Min. Interpass Temp. - Max. Preheat Maintenance
Gas(es)
(Mixture)
Flow Rate
Shielding
(Continuous or special heating where applicable should be recorded)
Trailing Backing
ELECTRICAL CHARACTERISTICS (QW-409) Current AC or DC Amps (Range)
Polarity Volts (Range)
(Amps and volts range should be recorded for each position, and thickness, etc. This information may be listed in a tabular form similar to that shown below. Tungsten Electrode Size and Type (Pure Tungsten, 2% Thorated, etc.) Mode of Metal Transfer for GMAW (Spray arc, short-circuiting arc, etc.) Electrode Wire feed speed range
TECHNIQUE (QW-410) String or Weave Bead Orifice or Gas Cup Size Initial and Interprass Cleaning (Brushing, Grinding, etc.) Method of Back Gouging Oscillation Contact Tube to Work Distance Multiple or Single Pass (per side) Multiple or Single Electrodes Travel Speed (Range) Peaning Other
Filler Metal Weld Layer(s)
Process
Class
Dia.
Current Type Polar
Amp Range
ITAC ASME IX Summary, 2007
Volt Range
Page 9-7
Travel Speed Range
Other (e.g., Remarks, Comments, Hot Wire Addition,Technique, Torch Angle, Etc.)
QW-483 SUGGESTED FORMAT FOR PROCEDURE QUALIFICATION RECORD (PQR) (See QW-200.2, Section IX, ASME Boiler and Pressure Vessel Code) Record Actual Conditions Used to Weld Test Coupon JOINTS (QW-402)
Company Name Procedure Qualification Record No. WPS No. Welding Process(es) Types (Manual, Automatic, Semi-Auto.)
Date
Groove Design of Test Coupon (For combination qualifications, the deposited weld metal thickness will be required for each filler metal or process used.)
BASE METALS (QW-403) Material Spec. Type or Grade P. No. Thickness of Test Coupon Diameter of Test Coupon Other
POST WELD HEAT TREATMENT (QW-407) to P-No.
Temperature Time Other
GAS(QW-408) Gas(es)
FILLER METALS (QW-404) SFA Specification AWS Classification Filler Metal F-No. Weld Metal Analysis A-No. Size of Filler Metal Other Weld Metal Thickness
Percent Composition (Mixture) Flow Rate
Shielding Trailing Backing
ELECTRICAL CHARACTERISTICS (QW-409) Current Polarity Amps. Volts Tungsten Electrode Size Other
POSITION (QW-405)
TECHNIQUE (QW-410)
Position of Groove Weld Progression (Uphill, Downhill) Other
Travel Speed String or Weave Bead Oscillation Multipass or Single Pass (per side) Single or Multiple Electrodes Other
PREHEAT (QW-406) Preheat Temp. Interpass Temp. Other
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QW-483 (Back) PQR No. Tensile Test (QW-150) Specimen No.
Width
Thickness
Area
Ultimate Total Load lb.
Ultimate Unit Stress psi
Type of Failure & Location
Guided-Bend Tests (QW-160) Type and Figure No.
Toughness Tests (QW-170) Specimen No.
Notch Location
Notch Type
Test Temp.
Impact Values
Lateral Exp. % Shear Mils
Drop Weight Break No Break
Fillet-Weld Test (QW-180) Result- Satisfactory: Macro - Results
Yes
No
Penetration into Parent Metal: Yes
No
Other Tests Type of Test Deposit Analysis Other ...................................................................................................................................................... Welders Name Tests conducted by:
Clock No.
Stamp No. Laboratory Test No.
We certify that the statements in this record are correct and that the test welds were prepared, welded, and tested in accordance with the requirements of Section IX of the ASME Code. Manufacturer Date
By
(Detail of record of tests are illustrative only and may be modified to conform to the type and number of test required by the Code.)
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NOTE:
API 653, Paragraph 11.1, now allows the use of AWS D1.1, AWS D.16 OR ASME Section IX SWPSs for the welding of ladders, platforms, any weld that is not directly attached to the tank. AWS D1.1: Structural Welding Code-Steel AWS D1.6: Structural Welding Code – Stainless Steel SWPS: Standard Welding Procedure Specifications
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ASME Section IX Welder Qualification Welder qualification establishes the skill level for the welder. The test positions are similar to the welding procedure positions. The essential variables for welder qualification are as follows: Position Joint Configuration Electrode Type and Size Process Base Metal Type Base Metal Thickness Technique (Up-hill or Down-hill)
• • • • • • •
(d) 4G
(b) 2G
(a) 1G
(c) 3G QW-461.3 Groove Welds in Plate -- Test Positions
Throat of weld vertical
Axis of weld horizontal
Axis of weld vertical
Axis of weld horizontal
45 deg.
QW-461.5 Fillet Welds in Plate - Test Positions
(a) 1F
(b) 2F
(c) 3F
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(d) 4F
(a) 1G Rotated
(c) 5G
(b) 2G
(d) 6G QW-461.4 Groove Welds in Pipe -- Test Positions
PERFORMANCE QUALIFICATION - POSITION AND DIAMETER LIMITATIONS (Within the Other Limitations of QW-303) Position and Type Weld Qualified [Note (1)] Qualification Test Weld
Position
Groove Plate and Pipe Over 24 in. O.D.
Plate - Groove
1G 2G 3G 4G 3G and 4G 2G, 3G and 4G Special Positions m(SP)
Plate - Fillet
1F 2F 3F 4F 3F and 4F Special Positions (SP)
F F,H F,V F,O F,V,O All SP,F ... ... ... ... ... ...
ITAC ASME IX Summary, 2007
Fillet
Pipe 24 in. O.D. F [Note (2)] F,H [Note (2)] F [Note (2)] F [Note (2)] F [Note (2)] F,H [Note (2)] SP,F ... ... ... ... ... ...
Page 9-12
Plate and Pipe F F,H F,H,V F,H,O All All SP,F F [Note (2)] F,H [Note (2)] F,H,V [Note (2)] F,H,O [Note (2)] All [Note (2)] SP, F [Note (2)]
PERFORMANCE QUALIFICATION - POSITION AND DIAMETER LIMITATIONS (Within the Other Limitations of QW-303) Position and Type Weld Qualified [Note (1)] Qualification Test Weld
Position
Groove Plate and Pipe Over 24 in. O.D.
Pipe - Groove [Note (3)] 1G 2G 5G 6G 2G and 5G Special Positions (SP) Pipe - Fillet [Note (3)]
1F 2F 2FR 4F 5F Special Positions (SP)
Fillet
Pipe 24 in. O.D.
F F,H F,V,O All All SP,F ... ... ... ... ... ...
F F,H F,V,O All All SP,F ... ... ... ... ... ...
Plate and Pipe F F,H All All All SP,F F F,H F,H F,H,O All SP,F
NOTES: (1) Positions of welding as shown in QW-461.1 and QW-461.2. F = Flat H = Horizontal V = Vertical O = Overhead (2) Pipe 2 7/8 in. O.D. and over. (3) See diameter restrictions in QW-452.3, QW-452.4 and QW-452.6
The general sequence for Welder qualification testing is as follows: •
Identify essential variables
•
Check equipment and materials for suitability
•
Check test coupon configuration and position
•
Monitor actual welding, to assure that it complies with applicable welding procedure
•
Select, identify and remove required test specimens
•
Test and evaluate specimens
•
Complete necessary paperwork
•
Monitor production welding
ITAC ASME IX Summary, 2007
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QW-484 SUGGESTED FORMAT FOR MANUFACTURERS RECORD OF WELDER OR WELDING OPERATOR QUALIFICATION TESTS (WPQ) See QW-301, Section IX, ASME Boiler and Pressure Vessel Code
Welders name Clock no. Stamp no. Welding process(es) used Type Identification of WPS followed by welder during welding of test coupon Base material(s) welded Thickness Manual or Semiautomatic Variables for Each Process (QW-350)
Actual Values Range Qualified
Backing (metal, weld metal, welded from both sides, flux, etc.) (QW-402) ASME P-No. to ASME P-No. (QW-403) ( ) Plate ( ) Pipe (enter diameter, if pipe) Filler metal specification (SFA): Classification (QW-404) Filler metal F-No. Consumable insert for GTAW or PAW Weld deposit thickness for each welding process Welding position (1G, 5G, etc.) (QW-405) Progression (uphill/downhill) Backing gas for GTAW, PAW or GMAW, fuel gas for OFW (QW-408) GMAW transfer mode (QW-409) GTAW welding current type/polarity Machine Welding Variables for the Process Used (QW-360)
Actual Values
Range Qualified
Direct/remote visual control Automatic voltage control (GTAW) Automatic joint tracking Welding position (1G, 5G, etc.) Consumable insert Backing (metal, weld metal, welded from back sides, flux, etc.) Guided-Bend Test Results Guided-Bend Tests Type
( )QW-462.2(Side) Results
( )QW-462.3(a) (Trans. R &F ) Type
( )QW-462.3(b) (Long R & F) Results
Visual examination results (QW-302.4) Radiographic test results (QW-304 and QW-305) (For alternative qualification of groove welds by radiography) Fillet Weld - Fracture test Length and percent of defects Macro test fusion Fillet leg size in. x in. Concavity/convexity Welding test conducted by Mechanical tests conducted by Laboratory test no.
in. in.
We certify that the statements in this record are correct and that the test coupons were prepared, welded and tested in accordance with the requirements of Section IX of the ASME Code. Organization Date
By
ITAC ASME IX Summary, 2007
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Section 10 Welding Metallurgy-97
WELDING METALLURGY Admixture: The interchange of filler metal and base metal during welding, resulting in weld metal of composition borrowed from both. Limited admixture is necessary to complete metallurgical union across the joint. Aging: The recrystallization that occurs over an extended period of time, resulting form austenite or other normally elevated-temperature structure being retained at a temperature and under conditions where it has no permanent stability. The result may be a change in properties or dimension. Under some circumstances, aging can be advantageous. Blowhole: A defect in metal caused by hot metal cooling too rapidly when excessive gaseous content is present. Specifically, in welding, a gas pocket in the weld metal, resulting from the hot metal solidifying without all of the gases having escaped to the surface. Crater cracks: Cracks across the weld bead crater, resulting form hot shrinkage. Heat-affected zone: The portion of the base metal, adjacent to a weld, the structure or properties of which have been altered by the heat of welding. Hot shrinkage: A condition where the thin weld crater cools rapidly while the remainder of the bead cools more slowly. Since metal contracts or shrinks as it cools, and shrinkage in the crater area is restrained by the larger bead, the weld metal at the crater is stressed excessively and may crack. Lamination: An elongated defect in a finished metal product, resulting from the rolling of a welded or other part containing a blowhole. Actually, the blowhole is stretched out in the direction of rolling. Pick-up: The absorption of base metal by the weld metal as the result of admixture. Usually used specifically in reference to the migration of carbon or other critical alloying elements from the base metal into the weld metal. Depending upon the materials involved, this can be an asset and not a liability. Segregation: The tendency of alloying elements, under certain heat conditions, to separate from the main crystalline constituent during transformation and to migrate and collect at the grain boundaries. There they often combine into undesirable compounds. Stringers: The tendency of segregated atoms of alloying elements or their compounds to attach to one another in thread-like chains. The problems encountered in welding can be better understood through a basic understanding of metallurgy. The metallurgical effects of welding are the effects of heat. Whether the welds are made by a gas flame, a metal arc, or electrical resistance, the effects on the parent metal are due to heat. ITAC Welding Metallurgy, 1995
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Every fusion welding operation involves a logical sequence of thermal or heat events. These include: 1. 2. 3. 4.
Heating of the metal Manipulation of the electrode or torch flame to deposit weld metal Cooling of the weld deposit as well as the base metal Reheating of the entire structure for stress-relieving purposes, in some instances
In every weld, the metal immediately under the flame or arc is in a molten state; the welded section is in the process of cooling off; and the section to be welded has not yet been heated and so is comparatively cool. These various conditions are encountered at the very same instant. See Figure M-1. As a result of welding, the structure of the welded ferrous metal may become martensitic, pearlitic or even austenitic in nature. The welder who knows metallurgy can predict which structure will be found when the weld has cooled. It is most important to know this because the final condition of the structure after welding is the one that determines the strength, hardness, ductility, resistance to impact, resistance to corrosion and similar mechanical and physical properties of the metal. All these properties may be affected by conditions that exist during the welding operation, so it is well to become acquainted with possible difficulties and see how they may be avoided. To avoid confusion, this discussion will be confined to steel. The effects of heating and cooling will not necessarily be the same for the non-ferrous metals and alloys. In some cases, a considerable difference in temperature ranges and other characteristics exist. The arc welding of steel involves very high temperatures. The resultant weld is essentially cast steel. Since the base metal very close to the weld is comparatively cool, a considerable variation in the grain structure develops within the weld area. The ironcarbon diagram, Figure M-2 shows how the rate at which the weld cools will alter the grain structure in both the weld itself and the immediately adjacent base metal, known technically as the heat -affected zone. Danger from the Air Unless extreme care to shield the weld metal is exercised during welding, the possibility exists that oxygen or nitrogen or both will be absorbed from the air. What either of these gases can do to weld metal is pitiful. An oxide or nitride coating will form along the grain boundaries. Oxidation along the grain boundaries greatly weakens the weld metal, and greatly reduces the impact strength and also the fatigue resistance of the welded part. Nitrogen forms iron nitrides in chemical composition with the iron, and these make the weld extremely brittle.
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The extent to which oxides and nitrides penetrate a steel will depend upon the type of steel, the temperature to which it is heated and the length of time it is held at this temperature. Extreme care should be exercised to prevent the penetration of air into high-temperature welding regions. The most satisfactory way to prevent oxide or nitride contamination in metal-arc welding is to make sure that the electrode has a coating that provides adequate shielding. The arc and weld metal may also be shielded by carbon dioxide (CO2) or vapor. In gas tungsten arc welding (GTAW) or gas metal arc welding (GMAW) (inert-gas-arc welding), the inert gas will provide the shielding. With submerged-arc welding, the molten flux that covers the arc does the job. Fluxes or a reducing flame provide the needed protection during gas welding. When the oxyacetylene torch is used for cutting, it is desirable to oxidize the steel. It is rapid oxidation that makes it possible for the flame to sever steel. Besides oxygen or nitrogen, another gas absorbed during welding may have harmful effects on some types of metals and alloys. This gas is hydrogen, and usually comes from moisture in the electrode coating or from the use of hydrogen in the welding flame. The presence of hydrogen in the weld metal will weaken the structure and lead to cracking of the weld. Hydrogen is a contributing cause of underbead cracking. To avoid this harmful weld defect, use low-hydrogen electrodes of the E-xx15, E-xx16 and E-xx18 series. Heat-Affected Zone Figure M-2 shows the close relationship that exists between thermal conditions, grain structure and hardness in the arc weld. So that this relationship might be clearly established, a photomicrograph of a section through a welded 0.25% carbon steel plate has been inserted in an iron-carbon diagram. This diagram was split on the 0.25% carbon line and opened up to allow insertion of the photomicrograph. The photomicrograph is of a single automatic weld bead. The bead as deposited on the 1/2 inch plate produced a heat-affected zone that extended for about 1/8 in. adjacent to the weld. This zone shows a variation in grain structure adjacent to the weld. This zone shows a variation in grain structure (staring at the bottom) from the normal base metal structure into a band of finer grain structure between the lower and upper critical temperature points and then to a coarse overheated grain structure adjacent to the weld. The extent of the change in the grain structure depends upon the maximum temperature to which the metal is subjected, the length of time this temperature exists, the composition of the steel, and the rate of cooling. The cooling rate will not only affect grain size but it will also affect physical properties. As a rule, faster cooling rates produce a slightly harder, less ductile and stronger steel. For low-carbon steels, the relatively small differences found in practice make insignificant changes in these values. However, with higher carbon content in appreciable amounts of alloying material, the effect may become serious.
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The speed of welding and the rate of heat input into the joint effects change in structure and hardness. On a given mass of base metal, at a given temperature, a small bead deposited at high speed produces a greater hardening than a larger bead deposited at a higher heat input per unit length of joint. This is because small high speed beads cool more rapidly than the larger high heat beads. The effect that heat from welding has on the base metal determines to a great degree the weldability of a metal and its usefulness in fabrication. A metal that is sensitive to heat conditions or heat changes, as in the case of high-carbon and some alloy steels, may require heat treatment both before and after welding. Admixture or Pick-up When a base metal is welded with a filler metal of different composition, the two metals will naturally mix and blend together in the molten weld pool. Consequently, the weld metal will be a mixture of two materials. it will not necessarily be an average of them, however. The amount of base metal picked up in the molten weld pool varies greatly relative to the amount of deposited electrode metal. Some welds are made up principally of base metal, while others are primarily deposited electrode metal. The specific process of welding, the rate of electrode travel, the current selected, the width of the joint, the base metal composition, the plate thickness -- all these factors determine the volume of base metal brought to a molten temperature, and therefore the amount of base metal pick-up or admixture into the weld. In some cases, the deposited metal and the base metal are sufficiently alike in composition that the amount of admixture is of little significance. At other times, admixture is an advantage in that the weld metal is made stronger or otherwise improved by a pick-up of carbon or other needed elements from the base metal. Unfortunately, under some conditions alloying elements or chemical combinations of the base metal tend to concentrate -- to precipitate, or to segregate during the heating and cooling cycle and reform into stringers or other arrangements that harden, embrittle, weaken or otherwise cause inferior welds. Sometimes, the stringer itself is a source of weakness. At other times, the segregation of an element or its loss into the slag or atmosphere "starves" the newly formed weld microstructure of elements needed for certain physical properties. In general, admixture should be limited unless the metals and the processes involved justify a procedure that calls for a specific amount of pick-up. This is discussed further in later chapters on the welding of specific metal groups. To minimize the effects of pick-up, electrode coatings or fluxes are often treated with alloying elements that bring the deposited metal up to the desired composition. These alloying elements replace those that might be destroyed or lost to either parent metal or weld metal during the high-temperature welding operation.
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Carbide Precipitation Sometimes, because of rapid cooling, steels, particularly stainless steels, are not given time to go through all of the temperature changes indicated in the iron-carbon diagram. As a result, a concentration of the solid solution (austenite) is retained at a temperature where it simply has no business existing. This being against nature, so to speak, the dissolved elements will eventually recrystallize. This type of recrystallization is known as aging. Suppose, however, the metal is reheated before recrystallization can occur. In this event, the carbon will crystallize out of the austenite as iron carbide. This phenomena is known as carbide precipitation. Stainless steels of the nickel-chromium variety are austenitic in nature even at room temperatures. When such steels are heated, as by welding operations, carbide precipitation is apt to occur. The carbides, or carbon compounds, are chromium as well as iron. When chromium is used up in this way, in chemical union with the precipitated carbon, the remaining austenite is deficient in the chromium element. The result is a serious reduction in the corrosion-resisting properties of the stainless steel. When the carbides are precipitated in stainless steel, they appear mainly at the grain boundaries. If subjected to corrosion, the carbides along the grain boundaries will be attacked readily. Severe corrosive conditions will cause the grains to lose their coherence and the steel to fail. In making a weld on stainless, there will always be a region some distance back from the weld where the base metal will be at the exact temperature of the precipitation range: 800-1500°F. Consequently, the stainless qualities of the structure will be lost unless steps are taken to prevent precipitation. Austenitic stainless steels may be stabilized against carbide precipitation by the addition of elements known as stabilizers. Such elements are columbium and titanium. These elements have a ready affinity for carbon; they will grab and hold fast the carbon that might otherwise have been attracted to the chromium. Moreover, both titanium and columbium carbide resemble stainless steel in having high resistance to corrosion. Stabilized stainless steels, therefore, will not fail under the combination of heat and corrosive attack. Austenitic stainless steels also are available in several grades with extra low carbon (ELC). Since there is less carbon, the possibility of chromium migration to the grain boundaries is minimized. It is well to remember that the stabilized and ELC austenitic steels will resist carbide precipitation. If the welded stainless is to be subjected to corrosive conditions, particularly at elevated temperatures, the base metal should be a stabilized steel and it should be welded with electrodes or filler rods that have also been stabilized.
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Crater Cracks In some instances, both arc welds and gas welds develop crater cracks. These come from hot shrinkage. The crater cools rapidly while the remainder of the bead is cooling slowly. Since the crater solidifies from all sides toward the center, the conditions are favorable to shrinkage cracks. Such crater cracks may lead to failures under stress -brittle failures since there is an inclination towards fracture without deformation. The remedy is to manipulate the electrode to fill up the craters when you are welding. Blowholes, Gas Pockets and Inclusions Other common welding defects known as blowholes, gas pockets and inclusions involve problems of electrode manipulation rather than metallurgy. These difficulties are created because of the welder's failure to retain the molten weld pool for sufficient time to float entrapped gas, slag and other forms of material. A blowhole or gas pocket represents a bubble of as in the liquid weld metal. A gas pocket is one that did not reach the surface before the metal began to freeze. Consequently, the gas remains entrapped in the solidified metal. Some gases, particularly hydrogen, are absorbed by the molten metal and are then given off as the metal beings to cool. If the metal is in a molten condition, the gas bubbles make their way to the surface and disappear. If the bubbles are trapped in the growing grains of solid metal, blowholes are the result. Blowholes are particularly prevalent in steels high in sulphur. In this case the entrapped gas is either sulphur dioxide or hydrogen sulphide, the hydrogen being supplied from moisture, the fuel gas (in gas welding), the electrode coating or the hydrogen atmosphere that surrounds the weld in atomic-hydrogen welding. Blowholes may be minimized in the weld area by using a continuous welding technique so that the weld metal will solidify continuously. Most welding operators, through practice, learn to develop welding techniques that will produce a relatively gas-free weld. One of the secrets of such a technique is to keep the molten weld pool at the temperature necessary for the rapid release of absorbed gases. At the same time an unbroken protective atmosphere must be provided over the pool. Modern electrode coatings aid in this problem, for they contain scavenging elements that cleanse the weld pool while it is in molten condition. Inclusions of slag and other foreign particles in the weld present a type of problem similar to gas pockets and blowholes. These inclusions tend to weaken the weld. Slag is frequently entrapped because of the operator's failure to manipulate torch, filler rod or electrode so as to maintain a molten condition long enough to float out all the foreign material. Ordinarily, the liquid slag freezes and forms a protective coating for the weld deposit. On some occasions, however, because of the force of the flame or arc, it is blown into the molten weld pool. The pool freezes before the slag particle or particles can float to the top, thus producing a defective weld. ITAC Welding Metallurgy, 1995
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Slag inclusions are more common in welds made in the overhead position. The lower density of the slag tends to keep it afloat on the weld pool. In overhead welding, the weld pool first forms at the narrow part of the vee, which is uppermost in the weld. Since the pool tends to drip if kept molten too long, the welder works to have it solidify as rapidly as possible. As a result, inclusions are frequent. This problem in overhead welding can be overcome by using gaseous, non-slagging types of electrodes. Faulty plate preparation contributes to slag inclusions. If edges of V-joints are beveled at too steep an angle and the gap between plates is too small, the weld metal bridges the gap and leaves a pocket at the root in which slag tends to collect. If back of joint is accessible, slag can be removed by back gouging; however, if this operation is omitted, the result is a defective weld. With a J-joint or U-joint, improper arc manipulation may burn back the inside corners and form pockets that can entrap slag or gases. In repair of a broken surface, a groove along the break line should be burned out or ground so as to provide clean surfaces properly angled and spaced. Failure to do so may leave an overhang of base metal or an unfilled crack that can entrap slag or gases. Surfaces to be welded should be thoroughly cleaned of scale, dirt, paint, lubricants, and other chemicals that might contribute to formation of gas or dirt inclusions in the weld. Welds that contain blowholes, gas pockets and inclusions may develop other defects upon hot work. By the action of hot working, the basic defects are exaggerated to form larger defects. For example, if a piece of weld metal containing a blowhole is rolled, the tendency is to flatten and elongate the hole. This develops a long fibrous defect running in the same direction as the piece that is rolled. Such a condition, known as a lamination, will reduce the strength of the metal, particularly in directions at right angles to the lamination.
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Section 11 Tech Report Writing-97
TECHNICAL REPORT WRITING LEGAL IMPLICATIONS I.
Preamble Comments A.
The completeness, factual data transmitted and final validity of any equipment inspection depends on the depth and scope of the officially submitted Inspection Report.
B.
The customer's perception of You as a qualified professional is always strongly influenced by what is contained in the report. Remember the "Image" comments earlier? Your report may well be "the make or break" factor about whether you or your company will be favorably considered for future inspection activities.
C.
An unknown factor usually exists relative to the "likes, dislikes and preferences" of the person who receives or acts on your inspection report. Some factors include: 1. 2. 3. 4. 5. 6.
D.
When developing the Inspection Report, consider: 1. 2. 3.
II.
Organization of data Length of report Factual versus theoretical Precise details or general statement. Recommendations or suggestion. Line-item coverage or report by exception.
Who will read and/or react to its contents, such as project engineers, superintendents, managers, supervisors, foremen, craftsmen, etc.? Can the report be understood, or will a translator be needed? If repair recommendations or sketches are submitted, how much "hand-holding" is required for them to be understood?
Date and Signature For a report to be auditable (legitimate by law), it must be dated and signed by the inspector/person involved. Basically, any item worth reporting is worthy of legal validation.
III.
Report Format/Descriptive Contents
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A.
Many of those reading/reacting to your report simply do not have time to attempt to grasp or correlate those items most useful to their response. Therefore, the report should be factual, concise and reasonably easy to grasp or understand.
B.
An "attention getter", up front statement is always helpful. Simple statement examples could be one of the following or some reasonably similar comment: 1.
Based on my inspection survey of Tank ______ on ____________, this equipment is considered to be in good condition and structurally sound for long term service.
or
2.
My findings/evaluation of this equipment indicates that minor, general internal corrosion of the bottom is occurring, but is of no near term concern. The remainder of this equipment is considered to be in good condition with no corrosion noted.
or
3.
The inspection survey indicates that moderate to sever internal corrosion exists. Component part thickness measurements, plus visual observations reflect the following conditions and recommendations:
NOTE:
C.
Remember that the person to whom you submit a report is a Client. It may be an "in-house" client for those inspecting equipment owned by their respective employer, or it may be a contract-owner relationship.
Many, if not most, clients will not appreciate, nor perhaps even tolerate, a report that contains "inflammatory" comments. In this context, inflammatory words, comments, opinions or predictions could be anything that, in the event of some future legal action, would place the equipment owner in a precarious, defensive position. Some examples are: 1. 2. 3. 4. 5.
Dangerous Explosion Hazardous Health Problem Unsafe
A simpler explanation would be any comment or wording that could be twisted or used out of context by lawyers in a negligence trial situation.
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Certainly, the comments listed above are not meant or intended to cause an inspector to prostitute himself or his profession by "soft-pedaling" or ignoring serious problems, plus informing the client whenever problems exist. Each client deserves a true, factual evaluation and condition report. It is possible, however, to structure your report comments in such a fashion that problems can be stated (or client informed) so as to impart various degrees of urgency or concern involving areas or component items requiring immediate or near term corrective action. IV.
Report Vocabulary A.
Each individual most probably has already established, or will establish, his own vocabulary (or word usage) to identify or project his evaluation of conditions noted during the inspection survey. Degrees of corrosion/deterioration exist, plus varying stages or phases of problems involving mechanical equipment, safety, environment, etc., must be described and/or commented upon. Some common descriptive phrases/comments I have become comfortable with are listed below. You will note that it is possible to make many combination statements by grouping certain descriptive words into comments that best describe your personal evaluation. 1. 2. 3. 4. 5. 6. 7.
B.
Very minor, general corrosion. Minor to moderate, etc., etc. Moderate, etc., etc. Moderate to severe, etc., etc. Severe, etc., etc. The results of this inspection survey indicate that repair as follows is recommended. Inspection/evaluation of this equipment indicates it to be in good condition and is considered OK for long term service.
Owner/client user Expectations You are hired (or used) to determine existing conditions of equipment, assess and evaluate the impact on future reliability, determine corrosion/metal thickness limitations or minimum requirements. You are expected to use your best judgment, expertise, experience and training to develop (perhaps even to recommend), the most cost effective, safest, operationally reliable method/degree of repair necessary to achieve the above conditions.
V.
Report Structure A.
Recall earlier comments regarding those who will receive your report plus those who will eventually react to your comments and/or recommendations. ITAC Tech. Report Writing, 1997
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B.
Methods, data organization, component part separation, etc., suggested for your strong consideration include: 1.
Method of presentation a. b. c. d.
2.
Keep the report as brief( but complete) as possible or practical. Keep it factual. If theorizing is required, make sure that this approach is recognized. Avoid, whenever possible, inflammatory words or comments. Be conscious of the economics involved. Don't recommend complete item renewal, when 50% renewal will provide the desired results.
Data Organization/Component Part Separation In reporting conditions found, separate into component tank parts (i.e., shell, bottom, fixed roof, I.F.R., etc.)
NOTE:
Do not intermingle comments/conditions, so that a thought pattern is established in the report readers mind on one component of the tank (i.e., shell) and then refer to the bottom in mid-stream. Keep comments separated in the report body and on the repair items recommended.
Ideally, repair items should be arranged in order, clearly defined and explicit enough, that the list can be given to maintenance personnel who can make proper repairs from the list. VI.
Review Comments The following are "Basic" in nature, but occasionally can be flexible to fit the needs of a particular situation: A.
Do's 1. 2. 3. 4. 5.
Keep as brief as possible, but present all factual data. A wide flexibility is necessary because of the range of comments required to satisfy numerous conditions. Provide suggestions or recommendations relative to repair if the client requests. Sketches involving repair or procedure details are a mark of competence. Be conscious of the economics involved that could result from your recommendations. Arrange data in an orderly fashion, separated into component parts for ease of reading and understanding. Sign and date report.
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B.
Don'ts 1. 2. 3. 4. 5.
Use inflammatory word, statements or opinions. Present a mass of data all intermingled in one statement. Make it a practice to theorize or guess as to problem cause. Present condition comments or data involving one major tank component into the same statement as data is presented on a completely different major component. Diminish your competency or professional image by a failure to submit a comprehensive, factual, readable report that will, by itself, be a future auditable document.
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BODY OF KNOWLEDGE API-653 ABOVEGROUND STORAGE TANK INSPECTOR CERTIFICATION EXAMINATION November 2006 (Replaces September 2005) API Authorized Aboveground Storage Tank Inspectors must have a broad knowledge base relating to tank inspection and repair of aboveground storage tanks. The API Aboveground Storage Tank Inspector Certification examination is designed to identify individuals who have satisfied the minimum qualifications specified in API Standard 653, Tank Inspection, Repair, Alteration, and Reconstruction. The examination consists of two parts. The closed book part tests the candidate on knowledge and tasks requiring everyday working knowledge of API Standard 653 and the applicable reference documents. The open book portion of the examination requires the use of more detailed information that the inspector is expected to be able to find in the documents, but would not normally be committed to memory. REFERENCE PUBLICATIONS: A. API Publications API Recommended Practice 571, Damage Mechanisms Affecting Equipment in Refining Industry API Recommended Practice 577, Welding Inspection and Metallurgy API Recommended Practice 575, Inspection of Atmospheric and Low-Pressure Storage Tanks API Standard 650, Welded Steel Tanks for Oil Storage API Recommended Practice 651, Cathodic Protection of Aboveground Petroleum Storage Tanks API Recommended Practice 652, Lining of Aboveground Petroleum Storage Tank Bottoms API Standard 653, Tank Inspection, Repair, Alteration, and Reconstruction B. ASME Publications American Society of Mechanical Engineers (ASME) Boiler & Pressure Vessel Code: Section V, Nondestructive Examination Section IX, Welding and Brazing Qualifications Note: Refer to the Publications Effectivity Sheet in the application package for a list of which editions, addenda, and supplements of the reference publications are effective for your exam. 11/06 Page 1
I. CALCULATIONS & TABULAR EVALUATIONS FOR EVALUATING THICKNESS MEASUREMENTS, WELD SIZES, AND TANK INTEGRITY (NOTE: Paragraph references for all formulas and calculations listed here should be checked for accuracy to the edition, addenda, or supplement for the examination you plan to take per the Publication Effectivity Sheet in the API Examination Application.) NOTE: Candidates are expected to be able to understand SI units (metric system) and the US customary units (inches, feet, PSI, etc.) and to use both system formulas. A. Calculation questions will be oriented toward existing tanks, not new tanks. API Authorized AST Inspectors should be able to check and perform calculations included in the following categories: 1. CORROSION RATES AND INSPECTION INTERVALS (API-575, Paragraph 7.6) The Inspector should be able to take inspection data and determine the internal and external inspection intervals. These calculations could be in either the “open book” or “closed book” portion of the exam. The Inspector must be able to calculate: a. b. c. d. e.
Metal Loss (including corrosion averaging - API-653, Section 4) Corrosion Rates Remaining Life Remaining Corrosion Allowance (API-653, Section 6) Inspection Interval (API-653, Section 6)
Remaining life (years) =
t actual - t minimum ___________________________________________
corrosion rate [inches (millimeters per year] Where: t actual = t minimum =
the thickness, in inches (millimeters), recorded at the time of inspection for a given location or component. minimum allowable thickness, in inches (millimeters), for a given location or component.
Corrosion rate =
t previous - t actual ____________________________________________________________________________
years between t actual and t previous t previous =
the thickness, in inches (millimeters), recorded at the same location as t actual measured during a previous inspection.
The formulas for performing the above calculations and rules for setting the inspection intervals may be "closedbook" during the exam. The inspector should also be able to compensate for the corrosion allowance. (Add or subtract based on requirements from the exam problem.) 2. JOINT EFFICIENCIES The inspector must be able to determine the joint efficiency, "E", of a tank weld. Inspector should be able to determine: a. Joint Types (API-653 Section 4, Table 4-2)
11/06 Page 2
b.
Type and extent of radiography performed (API 653, Table 4-2, Section 12; API 650, Section 6.1, Figure 61) c. Joint efficiency by reading API-653, Table 4-2 Determining joint efficiency may be part of a minimum thickness or maximum fill height problem since joint efficiency, "E", is used in the formulas for determining required thickness. (API-653, 4.3.3.1) 3. MAXIMUM FILL HEIGHT (HYDROSTATIC TESTING) The inspector should be able to determine the maximum liquid height for a tank. To determine the height, the “t min” formula in API-653 is rearranged as follows. This formula will be provided in the exam. The inspector is NOT expected to derive this formula by using transposition. a. Calculate the minimum allowable thickness per Section 4 of API 653 or the maximum fill height in the localized corroded area per:
? S ? E ? t min ? H? ? ? ? 2.6 ? D ? G ? b. Calculate the minimum allowable thickness per Section 4 of API 653 or the maximum fill height for an entire shell course per:
? S ? E ? t min ? H? ? ? +1 ? 2.6 ? D ? G ? 4. WELD SIZES FOR SHELL & ROOF OPENINGS The inspector should be familiar with determining the sizes and spacing of welds for shell openings to the extent of being able to use the information in the following Figures and Tables: a) API-650, Figures 3-4A, 3-4B, 3-5, 3-6, 3-9, 3-11, 3-13, 3-14, 3-16, 3-17, 3-18 b) API-650, Tables 3-6, 3-7, 3-9 c) API-653, Figures 9-1, 9-2, 9-3A, 9-3B
5. HOT TAPPING a) The Inspector should be familiar with the Hot Tapping requirements. (API-653, Paragraph 9.14) b) The inspector should be able to calculate the minimum spacing between an existing nozzle and a new hot tap nozzle. (API-653 Paragraph 9.14.3) 6. SETTLEMENT EVALUATION The Inspector should be able to calculate the maximum allowed settlement for the following: a) Edge Settlement (API-653 Appendix B.2.3, fig. B-5) b) Bottom Settlement Near the Tank Shell (API-653, Appendix B.2.4, Figures B-6, B-7, B-9 B-10, B-11, B12) c) Localized Bottom Settlement Remote from the Tank Shell (API-653, B.2.5, Fig. B-8) 7. NUMBER OF SETTLEMENT POINTS 11/06 Page 3
a)
The inspector should be able to calculate the number of survey points for determining tank settlement. (API653 12.5.1.2, Appendix B, Figure B-1, Figure B-2)
8. IMPACT TESTING The inspector should understand the importance of tank materials having adequate toughness. The inspector should be able to determine: a) b) c) d)
Tank design metal temperature (API-650, 2.2.9.3 & Figure 2-2) Material Group Number for a plate (API-650, Tables 2-3a and 2-3b) If impact testing is required (API-650, Figure 2-1) If impact test values are acceptable (API-650, Table 2-4)
9. EXISTING TANK SHELL - MINIMUM THICKNESS a) b) c) d) e)
Calculate “S”, allowable stress (API-653, 4.3.3.1 & 4.3.4.1) Determine “E”, Joint efficiency (API-653, 4.3.3.1, 4.3.4.1 & Tables 4-2 & 4-3) Determine “H”, liquid height (API-653, 4.3.3.1 & 4.3.4.1) Calculate- minimum acceptable thickness (API-653, 4.3.3.1 & 4.3.4.1) Calculate the thickness required for continued service (API-653, 4.3.3.1 & 4.3.4.1)
10. RECONSTRUCTED TANK SHELL - MINIMUM THICKNESS The inspector should be able to determine the minimum thickness of the shell of a reconstructed tank. The inspector should be able to: a) b) c) d)
Determine “Sd”, allowable stress for design condition (API-650, table 3-2, API-653, 8.4.2) Determine “St”, allowable stress for hydrostatic test condition (API-650, Table 3-2, API-653, 8.4.3) Calculate “td”, design shell thickness (API-650, 3.6.3.2, for tanks of 200 foot diameter and smaller) Calculate “tt”, hydrostatic test shell thickness (API-650, 3.6.3.2)
11. TANK SHELL - CORRODED AREA The inspector should be able to determine if a tank shell corroded area is acceptable for continued service. The inspector should be able to: a) b) c) d) e)
Select “t2”, minimum thickness exclusive of pits for a corroded area (API-653, 4.3.2.1.a & Figure 4-1) Calculate “L”, critical length for a corroded area (API-653, 4.3.2.1.b & Figure 4-1) Determine “t1”, average thickness for a corroded area (API-653, 4.3.2.1.c, 4.3.2.1.d, Figure 4-1) Determine “t min” for the corroded area “H”, height and “E”, joint efficiency will be based on corroded area (API-653, 4.3.3.1) Determine if “t1” and “t2” are acceptable (API-653, 4.3.3.1.a & .b)
12. TANK SHELL - PITTING The inspector should be able to evaluate a pitted area. The inspector should be able to: a) Calculate maximum acceptable pit depth (API-653, 4.3.2.2.a) b) Determine the maximum length of pits in any 8” vertical length (API-653, 4.3.2.2.b & Figure 4-2) 11/06 Page 4
13. BOTTOM PLATE MINIMUM THICKNESS The inspector should be able to determine if the bottom thickness is acceptable for continued service. The inspector should be able to: Calculate “MRT1” & “MRT2”, minimum remaining thickness at the next inspection. (API-653, 4.4.7.1) Calculate “O”, maximum period of operation. These formulas will be provided in the exam.
14. REPLACEMENT PLATES a)
The inspector should be able to determine the minimum dimensions for a replacement plate. (API-653, Figure 9-1)
15. LAP WELDED PATCH PLATES Per API-653, Paragraph 9.3 the inspector should be able to determine: a) The minimum thickness b) The minimum weld size c) The allowable size of the patch plate B. Typical code calculations and requirements that candidates will NOT be expected to know for purposes of the certification examination. 1. 2. 3. 4. 5. 6. 7. 8.
Required thickness calculations for wind, earthquake, and small internal pressures; Nozzle calculations for external loads; Flange calculations; Brazing requirements; Calculating venting requirements; Ladder, stairway, and other structural type calculations; Calculations for bottoms supported by grillage; Variable point method calculations
11/06 Page 5
II. WELDING ON ATMOSPHERIC ABOVEGROUND STORAGE TANKS ASME Section IX, Welding and Brazing Qualifications (NOTE: Candidiates should be familiar with the basic requirements for welding qualifications for procedures and welding personnel contained in ASME Section IX. Brazing is NOT covered on the examination. ) A. The inspector should have the knowledge and skills required to review a Procedure Qualification Record and a Welding Procedure Specification or to answer questions requiring the same level of knowledge and skill. Questions covering the specific rules of Section IX will be limited in complexity and scope to the SMAW and SAW welding processes. 1) Questions will be based on: a) No more than one process b) Filler metals limited to one c) Essential, non-essential, variables only will be covered d) Number, type, and results of mechanical tests e) Base metals limited to P1 f) Additional essential variables required by API-650 or API-653 2) The following are specifically excluded: a) Dissimilar base metal joints b) Supplemental powdered filler metals and consumable inserts c) Special weld processes such as corrosion-resistant weld metal overlay, hard-facing overlay, and dissimilar metal welds with buttering d) Charpy impact requirements and supplementary essential variables e) Any PQR and WPS included on the examination will not include heat treatment requirements. B. The inspector should know that the WPS must reference the applicable PQR and that the PQR must be signed and dated. C. API-650 and API-653: General welding requirements: 1) API Standard 650, Welded Steel Tanks for Oil Storage: The inspector should be familiar with and understand the general rules for welding in API-650, Section 7 and other rules for welding in API-650 such as those for: a) typical joints and definitions b) weld sizes c) restrictions on joints d) maximum allowable reinforcement e) inspection requirements 2) API Standard 653, Tank Inspection, Repair, Alteration, and Reconstruction: The inspector should be familiar with and understand the general rules for welding in API-653, Section 11.
11/06 Page 6
III. NONDESTRUCTIVE EXAMINATION ASME Section V, Nondestructive Examination NOTE: The examination will cover only the main body of each referenced Article, except as noted: A. Article 1, General Requirements: The inspector should be familiar with and understand: 1) 2) 3) 4) 5) 6)
The Scope of Section V, Rules for use of Section V as a referenced Code, Responsibilities of the Owner / User, and of subcontractors, Calibration, Definitions of “inspection” and examination”, Record keeping requirements.
B. Article 2, Radiographic Examination: The inspector should be familiar with and understand: 1) The Scope of Article 2 and general requirements, 2) The rules for radiography as typically applied on butt welded AST horizontal and vertical seams such as, but not limited to: · required marking · type, selection, number, and placement of IQIs, · allowable density · control of backscatter radiation · location markers 3) Records C. Article 6, Liquid Penetrant Examination, Including Mandatory Appendix II: The inspector should be familiar with and understand: 1) The Scope of Article 6, 2) The general rules for applying and using the liquid penetrant method such as but not limited to: a) procedures b) contaminants c) techniques d) examination e) interpretation f) documentation g) record keeping
D. Article 7, Magnetic Particle Examination (Yoke and Prod techniques only, excluding paragraphs T-765 and T-766): The inspector should be familiar with and understand the general rules for applying and using the magnetic particle method such as but not limited to: 1) The Scope of Article 7, 2) General requirements such as but not limited to requirements for: a) procedures b) techniques (Yoke and Prod only) c) calibration d) examination 11/06 Page 7
e) interpretation 3) Documentation and record keeping E. Article 23, Ultrasonic Standards, Section SE–797 only – Standard practice for measuring thickness by manual ultrasonic pulse-echo contact method: The inspector should be familiar with and understand; 1) The Scope of Article 23, Section SE-797, 2) The general rules for applying and using the Ultrasonic method 3) The specific procedures for Ultrasonic thickness measurement as contained in paragraph 7.
F. API-650 and API-653: General nondestructive examination requirements: 1) API Standard 650, Welded Steel Tanks for Oil Storage: The inspector should be familiar with and understand the general rules for NDE in API-650, Section 6. 2) API Standard 653, Tank Inspection, Repair, Alteration, and Reconstruction: The inspector should be familiar with and understand the general rules for NDE in API-653, Section 12
11/06 Page 8
IV. PRACTICAL KNOWLEDGE - GENERAL A. The following topics may be covered: 1) 2) 3) 4) 5) 6) 7) 8) 9) 10) 11) 12) 13) 14) 15) 16)
Organization and Certification Requirements. Types and Definitions of Inspections. Types Corrosion and Deterioration. Materials and Fabrication Problems. Welding. Nondestructive Examination (NDE) Methods Corrosion and Minimum Thickness Evaluation. Estimated Remaining Life. Inspection Interval Determination and Issues Affecting Intervals. Inspecting Relief Devices. Inspection Safety Practices. Inspection Records and Reports. Repairs / Alterations. Disassembly and Reconstruction. Hydro Testing, Pneumatic Testing
More information relevant to each of these categories is contained in section “V. PRACTICAL KNOWLEDGE SPECIFIC” where each reference publication applicable for study for the examination has been listed with the relevant topics that may be covered on the examination. B. Typical code requirements that candidates will NOT be expected to know for purposes of this certification examination. 1) 2) 3) 4) 5) 6) 7) 8) 9) 10) 11) 12) 13) 14) 15) 16)
Required thickness calculations for wind, earthquake, and small internal pressures Nozzle calculations for external loads; Flange calculations; Brazing requirements; Calculating venting requirements; Ladder, stairway, and other structural type calculations; NDE requirements for acoustic emission, eddy current, and motion radiography; or visual inspection per ASME Section V, Article 9 Technical interpretations of API & ASME Codes and Standards Welding process requirements other than shielded metal arc welding (SMAW) and submerged arc welding (SAW) API-650, Appendix S API-650 Appendix E API-650, Appendix R API-650, Appendix V API-650, Appendix D API-650, Appendix P API-650, Appendix C
11/06 Page 9
V. PRACTICAL KNOWLEDGE - SPECIFIC A. Each reference publication relative to study for the examination is listed below. A list of topics, which may be covered, is listed for each publication. Some topics may be listed under more than one publication. For example; ASME Section IX is the basic document for welding requirements as referenced by API-650 and API653. The referencing API documents contain additional welding requirements and exceptions or additions to those contained in ASME Section IX. Therefore, welding requirements may be listed under all three documents and all three documents may be listed under the general heading of “Welding on Tanks”.
API RP 571, Damage Mechanisms Affecting Fixed equipment in the Refining Industry ATTN: Inspectors are not required to memorize the definitions of terms included in Section 3 (Definitions of Terms and Abbreviations), but are expected to be familiar with the common terms and abbreviations and be able to find definitions, if needed in the solution of a test question. Test questions will be based on the following mechanisms only: 4.2.7 - Brittle Fracture 4.2.16 - Mechanical Fatigue 4.3.2 - Atmospheric Corrosion 4.3.3 - Corrosion under insulation (CUI) 4.3.8 - Microbiologically Induced Corrosion (MIC) 4.3.9 - Soil Corrosion 4.3.10 - Caustic Corrosion 4.5.1 - Chloride Stress Corrosion Cracking (Cl-SCC) 4.5.3 - Caustic Stress Corrosion Cracking (Caustic Embrittlement) 5.1.11 - Sulfuric Acid Corrosion
API Recommended Practice 575, Inspection of Atmospheric and Low-Pressure Storage Tanks NOTE: API RP-575 is a Recommended Practice and contains many general statements that are not strict requirements. Some questions on the examination related to RP-575 may contain phrases such as “it is best to” or “an inspector would normally” when information or statements from RP-575 are covered. In these cases it is important to be familiar with the content of RP-575 and to be able to pick the best answer of those given. All of RP-575 is applicable to the examination unless specifically excluded. A. The inspector should have a practical understanding and be familiar with the information contained in RP-575 ( excluding Appendix C) as related to: 1) 2) 3) 4) 5) 6)
types of tanks covered procedures to perform internal and external inspection the types of external and internal inspections procedures to determine suitability for continued service evaluation change-of-service effects on suitability for continued service evaluation and general condition of: a) distortions, flaws, windgirders, stiffeners, welds, and nozzles b) tank bottoms c) tank foundations d) causes of corrosion, leaks, cracks, and mechanical deterioration e) auxiliary equipment. f) anchor bolts, pipe connections, ground connections g) insulation. 11/06 Page 10
h) shells and roofs
API RP 577, Welding Inspection and Metallurgy 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14.
Definitions Welding Inspection Welding Processes Welding procedure Welding Materials Welder qualifications Non-destructive examination Metallurgy Refinery and Petrochemical Plant Welding Issues Terminology and symbols Actions to Address improperly made production welds Welding procedure review Guide to common filler metal selection Example report of RT results
API Standard 653, Tank Inspection, Repair, Alteration, and Reconstruction and the related portions of API Standard 650, Welded Steel Tanks for Oil Storage (NOTE: all of API-653 is applicable to the examination unless specifically excluded.) A. Tank Inspection, NDE, and Testing 1) The inspector should have a practical understanding and be familiar with the information contained in API-653 related to general inspection practices such as: a) types of tanks covered b) applicable inspection tasks for internal and external inspection (e.g., API Standard 653, Appendix C, Checklist for Tank Inspection). c) safe working practices d) thickness and dimensional measurements and tolerances e) requirements of the three types of external inspections and an internal inspection f) frequencies and intervals for external and internal inspection g) alternatives to the required internal inspection intervals h) NDE procedures and NDE personnel qualification requirements i) types of roofs and seals and types of deterioration j) reasons for inspection and causes of deterioration of storage tanks k) procedures to check or test storage tanks for leaks l) tools and equipment for tank inspection m) failure assessment and deterioration of auxiliary equipment n) suitability for continued service. o) change-of-service effects on suitability for continued service p) evaluation of tank bottom conditions q) evaluate tank foundation conditions r) risk of failure due to brittle fracture s) evaluate the causes of corrosion, leaks, cracks, and mechanical deterioration. t) evaluate the condition of anchor bolts, pipe connections, ground connections, and insulation
11/06 Page 11
2) The inspector should have an understanding and be able to perform calculations related to: (See also previous section on “CALCULATIONS FOR EVALUATING THICKNESS MEASUREMENTS AND TANK INTEGRITY”) a) b) c) d) e) f) g) h) i) j) 3)
actual and minimum required thickness for shell plates maximum allowable fill height required thickness for hydrotesting and for elevated temperatures evaluation of corroded areas and pits on shell plates t min, corrosion rate, inspection interval and remaining corrosion allowance distortions, flaws, windgirders, stiffeners, welds, and nozzles. minimum thickness for tank bottoms and annular plate rings and shell rings evaluate the effects of tank bottom settlement and acceptable limits evaluate the condition of tank shells and roofs. weld size at roof-to-shell and bottom-to-shell junctions per design requirements
The inspector should have an understanding of the requirements for performing repairs and alterations such as: a) b) c) d) e) f) g) h) i)
definitions of repairs and alterations repairs to foundations, shell plates, welds, tank bottoms, nozzles & penetrations, roofs, seals, knowledge of the repair/alteration material and toughness requirements use of unidentified materials for repairs/alterations hot tap requirements and procedures inspection and NDE requirements for repairs and alterations hydrostatic and leak testing requirements lap welded patch plates (API-653, 9-3) new bottoms supported by grillage API-650, Appendix I, Excluding calculations)
4) The inspector should have an understanding of the requirements for recording the inspection data and records related to inspection, repairs, and alterations such as: a) nameplate requirements b) record-keeping requirements c) reports for inspection, repair and alterations
API Recommended Practice 651, Cathodic Protection of Aboveground Petroleum Storage Tanks NOTE: Only Sections 1, 2, 3, 4, 5, 6, 8, and 11 will be covered on the examination. A. The inspector should have a practical understanding and be familiar with the information contained in RP-651 related to: 1) 2) 3) 4)
Corrosion of Aboveground Steel Storage Tanks Determination of Need for Cathodic Protection Methods of Cathodic Protection for Corrosion Control Operation and Maintenance of Cathodic Protection Systems
B. Information contained in RP-651 which the inspector will not be examined on: 1) 2)
design of cathodic protection systems sources, detection, and control of interference currents
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API Recommended Practice 652, Lining of Aboveground Petroleum Storage Tank Bottoms A. The inspector should have a practical understanding and be familiar with the information contained in RP-652 related to: 1) 2) 3) 4) 5) 6)
types of tank bottom linings and advantage and disadvantages of each considerations for recommending tank bottom linings causes of tank bottom lining failures types of tank bottom lining materials surface preparation requirements for the installation of tank bottom linings issues affecting the application of a tank bottom lining
11/06 Page 13
Publications Effectivity Sheet For API 653 Exam Administration: March 19, 2008 Listed below are the effective editions of the publications required for the March 19, 2008 API 653, Aboveground Storage Tank Inspector Examination. ¡ API Recommended Practice 571, Damage Mechanisms Affecting Fixed Equipment in the Refining Industry, First Edition, December 2003. IHS Product code API CERT 653_571 (includes only the portions specified below) ATTENTION: Only the following mechanisms to be included: 4.2.7 - Brittle Fracture 4.2.16 - Mechanical Fatigue 4.3.2 - Atmospheric Corrosion 4.3.3 - Corrosion under insulation (CUI) 4.3.8 - Microbiologically Induced Corrosion (MIC) 4.3.9 - Soil Corrosion 4.3.10 - Caustic Corrosion 4.5.1 - Chloride Stress Corrosion Cracking (Cl-SCC) 4.5.3 - Caustic Stress Corrosion Cracking (Caustic Embrittlement) 5.1.1.11 - Sulfuric Acid Corrosion
¡ ¡ ¡
¡ ¡ ¡ ¡
API Recommended Practice 575, Inspection of Atmospheric and Low-Pressure Storage Tanks, Second Edition, May 2005. IHS Product Code API CERT 575 API Recommended Practice 577 – Welding Inspection and Metallurgy, First Edition, October 2004. IHS Product Code API CERT 577 API Standard 650, Welded Steel Tanks for Oil Storage, Tenth Edition, November 1998, including Addendum 1 (March 2000), Addendum 2 (Nov. 2001) and Addendum 3 (Sept. 2003) and Addendum 4 (December 2005). IHS Product Code API CERT 650 API Recommended Practice 651, Cathodic Protection of Aboveground Petroleum Storage Tanks, Third Edition, January 2007. IHS Product Code API CERT 651 API Recommended Practice 652, Lining of Aboveground Petroleum Storage Tank Bottoms, Third Edition, October 2005. IHS Product Code API CERT 652 API Standard 653, Tank Inspection, Repair, Alteration, and Reconstruction, Third Edition, December 2001; including Addendum 1 ( September 2003) and Addendum 2 (November 2005). - IHS Product Code API CERT 653 American Society of Mechanical Engineers (ASME), Boiler and Pressure Vessel Code, 2004 edition with the 2005 Addenda and 2006 addenda.
i. ASME Section V, Nondestructive Examination, Articles 1, 2, 6, 7 and 23 (section SE-797 only) ii. Section IX, Welding and Brazing Qualifications (Section QW only) IHS Product Code for the ASME package API CERT 653 ASME. Package includes only the above excerpts necessary for the exam.
API and ASME publications may be ordered through IHS Documents at 303-397-7956 or 800-854-7179. Product codes are listed above. Orders may also be faxed to 303-397-2740. More information is available at http://www.ihs.com. API members are eligible for a 30% discount on all API documents; exam candidates are eligible for a 20% discount on all API documents. When calling to order, please identify yourself as an exam candidate and/or API member. Prices quoted will reflect the applicable discounts. No discounts will be made for ASME documents. Note: API and ASME publications are copyrighted material. Photocopies of API and ASME publications are not permitted. CD-ROM versions of the API documents are issued quarterly by Information Handling Services and are allowed. Be sure to check your CD-ROM against the editions noted on this sheet.
6/07
Study Sheets Based on API 653 Exam Information The following is a collection of questions remembered by various students who took the API 653 Exam in the past. This study sheet is designed to help a student prepare for the API 653 Exam. Read each question carefully and select the best answer by circling your choice. After selection of your answer, write in the section number and publication in which your answer was found. Look up each question in the reference publications listed below; remember, this exercise is to help you to learn to use the reference material. Generally, the assignment is broken into several sections. Each section should take approximately one hour to complete. Answers will be discussed at the beginning of class the following morning. The answers will be found in the following reference publications: API 571, Damage Mechanisms Affecting Fixed Equipment in the Refining Industry, First Edition, December, 2003 ATTENTION: Only the following mechanisms are included in the exam: Par. 4.2.7 – Brittle Fracture Par. 4.2.16 – Mechanical Fatigue Par. 4.3.2 – Atmospheric Corrosion Par. 4.3.3 – Corrosion Under Insulation (CUI) Par. 4.3.8 – Microbiologically Induced Corrosion (MIC) Par. 4.3.9 – Soil Corrosion Par. 4.3.10 – Caustic Corrosion Par. 4.5.1 – Chloride Stress Corrosion Cracking (Cl-SCC) Par. 4.5.3 – Caustic Stress Corrosion Cracking (Caustic Embrittlement) Par. 5.1.1.11 – Sulfuric Acid Corrosion API RP 575, Guidelines and Methods for Inspection of Existing Atmospheric and Lowpressure Storage Tanks, Second Edition, May, 2005 API RP 577, Welding Inspection and Metallurgy, First Edition, October, 2004 API 650, Welded Steel Tanks for Oil Storage, Tenth Edition, November, 1998, including Addendum 1 (March, 2000), Addendum 2 (November, 2001), Addendum 3 (September, 2003) and Addendum 4 (December 2005). API RP 651, Cathodic Protection of Aboveground Petroleum Storage Tanks, Third Edition, January, 2007 API RP 652, Lining of Above Ground Petroleum Storage Tank Bottoms, Third Edition, October, 2005 1/07 ITAC API 653 Exam Prep Homework #1 Questions Page 1
ITAC API 653, Tank Inspection, Repair, Alteration and Reconstruction, Third Edition, December, 2001, including Addendum 1 (September, 2003) and Addendum 2 (November, 2005). ASME Boiler & Pressure Vessel Code, 2004 Edition, with 2005 and 2006 Addenda Section V, Nondestructive Examination, Articles 1, 2, 6, 7 and 23 (Section SE-797 only) Section IX, Welding and Brazing Qualifications
1/07 ITAC API 653 Exam Prep Homework #1 Questions Page 2
ITAC 1.
What is the minimum thickness for a tank floor plate with no means for leak detection or secondary containment if an RBI program is not in place? a. b. c. d.
.005” .050” .075” .100”
Section:
2.
Reference Publication:
Which one of the following types of external floating roofs does not require a check valve in the roof drain? a. b. c. d.
Annular pontoon (single deck) Double deck Pan-type Plastic sandwich-panel-sphere type floating roof
Section: 3.
Reference Publication:
Surface preparation is a critical part of the lining operation, generally abrasive blast to a white metal finish of __________ is desired. a. b. c. d.
NACE NACE NACE NACE
No. No. No. No.
1/SSPC-SP5 2/SSPC-SP10 3/SSPC-SP15 4/SSPC-SP20
Section: 4.
When a full hydrostatic test is required, it shall be held for _____ hours. a. b. c. d.
8 12 16 24
Section: 5.
Reference Publication:
Reference Publication:
Inspectors should also be alert to accumulation of dry pyrophoric material that may ignite during inspection These accumulations may occur on the tank bottom or ________. a. b. c. d.
on the top of rafters on the outside of the shell under the floor on handrails
Section:
Reference Publication: 1/07 ITAC API 653 Exam Prep Homework #1 Questions Page 3
ITAC 6.
The portion of the base metal whose microstructure has been altered by the heat of welding is the . a. b. c. d.
dilution zone micro zone fusion zone heat affected zone
Section: 7.
Reference Publication:
Radiographic film density shall be checked by a densitometer calibrated on a step wedge film traceable to . a. b. c. d.
API 650 ASNT-SNT-TC-1A ASME Section IX a national standard
Section: 8.
A 200 diameter tank, 40 tall, storing a product with a specific gravity of .85. A corroded area was noted with UT on the bottom course with a minimum thickness of .51” at 1 above the weld. No thinning was noted within 10” of any weld. What is the L length of the corroded area? a. b. c. d.
not enough information to answer 10.10” 37.37” 40”
Section: 9.
Reference Publication:
Reference Publication:
A gummy carbonaceous substance, fouling service, is stored in a tank. Where would problems most likely occur? a. b. c. d.
The floating suction The operation of check valves Around nozzles On the floor
Section:
Reference Publication:
1/07 ITAC API 653 Exam Prep Homework #1 Questions Page 4
ITAC 10.
Routine visual in-service inspections of aboveground storage tanks from the ground may be done by ? a. b. c. d.
authorized inspectors only owner/user personnel other than authorized inspectors jurisdictional inspectors only insurance inspectors only
Section: 11.
Reference Publication:
An existing tank, 48 feet high with a diameter of 127 feet, is undergoing major repairs. What is the maximum out-of-plumbness allowed? a. b. c. d.
1.27” 4.8” 5.0” 5.76”
Section: 12.
Which of the following is not considered shell distortion? a. b. c. d.
Uniform settlement of a tank Out-of-roundness of a tank Flat spots Peaking and banding at weld joints
Section: 13.
Reference Publication:
A welder that qualifies on a plate groove weld can weld a. b. c. d.
.
groove weld only groove and fillet welds fillet welds only “J” welds only
Section: 14.
Reference Publication:
Reference Publication:
An 8” NPS hot tap is to be added to a tank. What is the minimum wall thickness of the nozzle neck? a. b. c. d.
Schedule 40 Schedule 60 Standard weight Extra-strong
Section:
Reference Publication:
1/07 ITAC API 653 Exam Prep Homework #1 Questions Page 5
ITAC 15.
A welder may be qualified by RT in any welding process except for which of the following? a. b. c. d.
GMAW (short-circuiting mode) GMAW (spray-arc mode) GTAW SMAW
Section: 16.
During the reconstruction of a tank, the original construction material was not listed in Table 3-2, of API 650, an allowable stress value of ______ shall be used. a. b. c. d.
the lesser of 2/5 yield strength or 2/3 tensile strength the lesser of 2/3 yield strength or 2/5 tensile strength the lesser of 5/7 yield strength or 3/4 tensile strength the lesser of 99% yield strength or 99% tensile strength
Section: 17.
2” 4” 8” 10”
Section:
Reference Publication:
A formal visual external inspection by an Authorized Inspector shall be made at least every ______ years or RCA/4N years, whichever is less. a. b. c. d.
2 3 4 5
Section: 19.
Reference Publication:
What is the maximum spacing for MT prods? a. b. c. d.
18.
Reference Publication:
Reference Publication:
During the inspection of an AST it is discovered that the ground wire connection has come loose. How should the ground system be inspected? a. b. c. d.
Ignore it Test the current using a volt ohm meter PT or MT Visually checked
Section:
Reference Publication: 1/07 ITAC API 653 Exam Prep Homework #1 Questions Page 6
ITAC 20.
The presence of rock under the steel bottom of an AST would have what effect? a. b. c. d.
Porosity in the bottom Promote corrosion Create longer tank bottom life Have no effect on the tank bottom
Section: 21.
Reference Publication:
During a welder qualification test on 3/8” plate in the horizontal position, how many transverse bends are required? a. b. c. d.
6 side bends 2 nick breaks 1 face and 1 root bends 4 tinsel specimens
Section: 22.
Reference Publication:
If a contractor is to relocate or reconstruct an aboveground storage tank, the limits of responsibilities are defined by ? a. b. c. d.
API 653 the contractor the authorized inspector the owner/operator
Section: 23.
A new tank is to be hydrostatically tested. The tank is constructed from ASTM A 36M steel. What allowable stress must be used to determine the maximum hydrostatic test head for the tank. a. b. c. d.
29,400 23,200 24,900 27,000
Section: 24.
Reference Publication:
psi psi psi psi Reference Publication:
Where should the numbers be placed on a radiograph? a. b. c. d.
Under the film. On the material being radiographed. Under the material being radiographed. On the film source pack.
Section:
Reference Publication: 1/07 ITAC API 653 Exam Prep Homework #1 Questions Page 7
ITAC 25.
A new tank is placed in service. In seven years, which of the following inspections should have been made? a. b. c. d.
routine inspection routine and external inspections routine, external, visual and internal inspections routine visual, formal visual (external) and UT inspections
Section:
Reference Publication:
1/07 ITAC API 653 Exam Prep Homework #1 Questions Page 8
Study Sheets Based on API 653 Exam Information The following is a collection of questions remembered by various students who took the API 653 Exam in the past. This study sheet is designed to help a student prepare for the API 653 Exam. Read each question carefully and select the best answer by circling your choice. After selection of your answer, write in the section number and publication in which your answer was found. Look up each question in the reference publications listed below; remember, this exercise is to help you to learn to use the reference material. Generally, the assignment is broken into several sections. Each section should take approximately one hour to complete. Answers will be discussed at the beginning of class the following morning. The answers will be found in the following reference publications: API 571, Damage Mechanisms Affecting Fixed Equipment in the Refining Industry, First Edition, December, 2003 ATTENTION: Only the following mechanisms are included in the exam: Par. 4.2.7 – Brittle Fracture Par. 4.2.16 – Mechanical Fatigue Par. 4.3.2 – Atmospheric Corrosion Par. 4.3.3 – Corrosion Under Insulation (CUI) Par. 4.3.8 – Microbiologically Induced Corrosion (MIC) Par. 4.3.9 – Soil Corrosion Par. 4.3.10 – Caustic Corrosion Par. 4.5.1 – Chloride Stress Corrosion Cracking (Cl-SCC) Par. 4.5.3 – Caustic Stress Corrosion Cracking (Caustic Embrittlement) Par. 5.1.1.11 – Sulfuric Acid Corrosion API RP 575, Guidelines and Methods for Inspection of Existing Atmospheric and Lowpressure Storage Tanks, Second Edition, May, 2005 API RP 577, Welding Inspection and Metallurgy, First Edition, October, 2004 API 650, Welded Steel Tanks for Oil Storage, Tenth Edition, November, 1998, including Addendum 1 (March, 2000), Addendum 2 (November, 2001), Addendum 3 (September, 2003) and Addendum 4 (December, 2005). API RP 651, Cathodic Protection of Aboveground Petroleum Storage Tanks, Third Edition, January, 2007 API RP 652, Lining of Above Ground Petroleum Storage Tank Bottoms, Third Edition, October, 2005 1/07 ITAC API 653 Exam Prep Homework #2 Questions Page 1
ITAC API 653, Tank Inspection, Repair, Alteration and Reconstruction, Third Edition, December, 2001, including Addendum 1 (September, 2003) and Addendum 2 (November, 2005). ASME Boiler & Pressure Vessel Code, 2004 Edition, with 2005 and 2006 Addenda Section V, Nondestructive Examination, Articles 1, 2, 6, 7 and 23 (Section SE-797 only) Section IX, Welding and Brazing Qualifications
1/07 ITAC API 653 Exam Prep Homework #2 Questions Page 2
ITAC 26.
How many roof rafters must a plank cross over for inspection of the roof of a tank? a. b. c. d.
1 2 3 4
Section: 27.
The maximum acceptable undercutting on horizontal butt welds of a reconstructed tank is _____ inch. a. b. c. d.
1/64 1/32 1/16 1/8
Section: 28.
Reference Publication:
The minimum number of settlement points around a tank periphery is a. b. c. d.
.
12 10 8 6
Section: 29.
Reference Publication:
Reference Publication:
A weld shall be acceptable by visual inspection if the inspection shows which of the following? a. b. c. d.
The weld has no cracks, no undercutting, and less than 20% coldlap. The weld has no cracks, undercutting is acceptable, and any surface porosity does not exceed one cluster in any 2” of length and the diameter of each cluster does not exceed 1/16”. The weld has no crater cracks or other surface cracks, undercutting is acceptable, and any surface porosity does not exceed one cluster in any 3” of length and the diameter of each cluster does not exceed 1/8”. The weld has no crater cracks, other surface cracks or arc strikes in or adjacent to the welded joint, undercutting is acceptable, and any surface porosity does not exceed one cluster in any 4” of length and the diameter of each cluster does not exceed 3/32”.
Section:
Reference Publication:
1/07 ITAC API 653 Exam Prep Homework #2 Questions Page 3
ITAC 30.
Penetrameters (IQIs)are normally placed on the _____ of the part being examined. a. b. c. d.
source side film side weld side obverse side
Section: 31.
External, UT measurements of a new tank shell shall be made not later than _____ years after commissioning. a. b. c. d.
5 4 3 2
Section: 32.
Reference Publication:
Thin film linings are usually used for application to a. b. c. d.
.
good welding techniques NDE indications weld flaws acceptable weld discontinuities
Section:
.
the bottoms of new storage tanks. pitted bottoms of older storage tanks. corroded bottoms of previous service tanks. rough and pitted surfaces.
Section: 34.
Reference Publication:
Cracks, lack of fusion and rejectable slag and porosity are examples of a. b. c. d.
33.
Reference Publication:
Reference Publication:
With a horizontal sweep board 36” long, peaking shall not exceed _____ inch. a. b. c. d.
0.250 0.375 0.500 0.625
Section:
Reference Publication:
1/07 ITAC API 653 Exam Prep Homework #2 Questions Page 4
ITAC 35.
If a welder tests in a 6G position, he qualifies to weld a. b. c. d.
all positions uphill only downhill only vertical only
Section: 36.
An anode is a. b. c. d.
.
Reference Publication:
Widely scattered pits may be ignored, provided a. b. c. d.
Reference Publication:
The critical zone of the tank bottom is within the a. b. c. d.
.
no pit depth results in the remaining shell thickness being less than 1/2t min acceptable tank shell thickness, exclusive of corrosion allowance. the average pit depth is greater than 1/2t min, exclusive of the corrosion allowance no pit depth is greater than 1/2t min, including the corrosion allowance no pit depth is less than 1/2t min, including the corrosion allowance
Section: 38.
Reference Publication:
an electrode of an electrochemical cell at which no corrosion occurs an electrode of an electrochemical cell at which corrosion occurs a chemical substance containing ions that migrate a metallic connection that provides electrical continuity
Section: 37.
.
.
Annular plate ring, within 6” of the shell or within 6” of the inside edge of the annular ring. Annular plate ring, within 10” of the shell or within 10” of the inside edge of the annular ring. Annular plate ring, within 12” of the shell, or within 12” of the inside edge of the annular plate ring. Annular or bottom plates within 3 inches of the inside edge of the shell.
Section:
Reference Publication:
1/07 ITAC API 653 Exam Prep Homework #2 Questions Page 5
ITAC 39.
The space between the outer periphery of the roof and the tank shell of an external floating roof tank shall be sealed by a flexible device that provides . a. b. c. d.
a minimum 1/2” gap over no more than 24” an area of no more than 15 square inches opening calculated by measuring the length and width of the gaps. a reasonably close fit to the shell surfaces a minimum of 3 openings 24” long with gaps no more than 1/4”
Section: 40.
Reference Publication:
What is the recommended operating limits for carbon steel in caustic service if the material is stress relieved? a. b. c. d.
0oF to 180oF 180oF to 210oF 210oF to 270oF carbon steel does not need to be stress relieved
Section: 41.
A full hydrostatic test is always required on a. b. c. d.
.
a tank that has an annular plate installed with the longest dimension less than 12” a tank that has a door sheet installed a tank that has a nozzle 12” NPS installed a reconstructed tank
Section: 42.
Reference Publication:
Reference Publication:
What is the maximum temperature that dry MT can be used? a. b. c. d.
o 600 F o 135 F o 400 F Within the temperature range limitations set by the manufacturer
Section:
Reference Publication:
1/07 ITAC API 653 Exam Prep Homework #2 Questions Page 6
ITAC 43.
If a repair/modification weld is made on a tank shell plate that is thicker than 1”, the base metal within 3 inches of the welding shall be heated to a temperature of approximately degrees. a. b. c. d.
120o F o 140 F o 160 F o 200 F
Section: 44.
What is the main factor in determining the efficiency of a rivet joint in a tank? a. b. c. d.
The allowable stress of the rivets The number of rivet rows and type of joint The allowable stress of the plate Whether the joints have butt straps or not
Section: 45.
Reference Publication:
It is not necessary for the inspector to check which of the following? a. b. c. d.
All test results on the PQR All essentials and non-essentials on WPS All essentials and non-essentials on WPS and PQR All non-essentials on PQR
Section: 46.
Reference Publication:
Reference Publication:
A new tank built in January, 1984, was removed from service and internally inspected in January, 1994. The bottom course of the tank showed the most general corrosion (no isolated corrosion was found). The original thickness of the bottom course of the tank was 1”. The measured thickness of the bottom course at the inspection was 0.93”. Determine the yearly corrosion rate. a. b. c. d.
.0035” .0070” .0140” .0700”
Section:
Reference Publication:
1/07 ITAC API 653 Exam Prep Homework #2 Questions Page 7
ITAC 47.
When the corrosion rates of a tank are not known and the bottom plate thickness can not otherwise be determined, inspection(s) should be performed within the next _____ years of tank operation to establish corrosion rates. a. b. c. d.
5 10 15 20
Section: 48.
The maximum spacing of settlement points is _____ feet around the circumference of the tank. a. b. c. d.
40 35 32 25
Section: 49.
Reference Publication:
A 100 foot diameter tank must have at least _____ inch thick shell plates. a. b. c. d.
1/8 3/16 1/4 1/2
Section: 50.
Reference Publication:
Reference Publication:
The maximum acceptable undercutting on vertical butt welds of a reconstructed tank is _____ inch. a. b. c. d
1/64 1/32 1/16 1/8
Section:
Reference Publication:
1/07 ITAC API 653 Exam Prep Homework #2 Questions Page 8
Study Sheets Based on API 653 Exam Information The following is a collection of questions remembered by various students who took the API 653 Exam in the past. This study sheet is designed to help a student prepare for the API 653 Exam. Read each question carefully and select the best answer by circling your choice. After selection of your answer, write in the section number and publication in which your answer was found. Look up each question in the reference publications listed below; remember, this exercise is to help you to learn to use the reference material. Generally, the assignment is broken into several sections. Each section should take approximately one hour to complete. Answers will be discussed at the beginning of class the following morning. The answers will be found in the following reference publications: API 571, Damage Mechanisms Affecting Fixed Equipment in the Refining Industry, First Edition, December, 2003 ATTENTION: Only the following mechanisms are included in the exam: Par. 4.2.7 – Brittle Fracture Par. 4.2.16 – Mechanical Fatigue Par. 4.3.2 – Atmospheric Corrosion Par. 4.3.3 – Corrosion Under Insulation (CUI) Par. 4.3.8 – Microbiologically Induced Corrosion (MIC) Par. 4.3.9 – Soil Corrosion Par. 4.3.10 – Caustic Corrosion Par. 4.5.1 – Chloride Stress Corrosion Cracking (Cl-SCC) Par. 4.5.3 – Caustic Stress Corrosion Cracking (Caustic Embrittlement) Par. 5.1.1.11 – Sulfuric Acid Corrosion API RP 575, Guidelines and Methods for Inspection of Existing Atmospheric and Lowpressure Storage Tanks, Second Edition, May, 2005 API RP 577, Welding Inspection and Metallurgy, First Edition, October, 2004 API 650, Welded Steel Tanks for Oil Storage, Tenth Edition, November, 1998, including Addendum 1 (March, 2000), Addendum 2 (November, 2001), Addendum 3 (September, 2003) and Addendum 4 (December, 2005). API RP 651, Cathodic Protection of Aboveground Petroleum Storage Tanks, Third Edition, January, 2007 API RP 652, Lining of Above Ground Petroleum Storage Tank Bottoms, Third Edition, October, 2005 1/07 ITAC API 653 Exam Prep Homework #3 Questions Page 1
ITAC API 653, Tank Inspection, Repair, Alteration and Reconstruction, Third Edition, December, 2001, including Addendum 1 (September, 2003) and Addendum 2 (November, 2005). ASME Boiler & Pressure Vessel Code, 2004 Edition, with 2005 and 2006 Addenda Section V, Nondestructive Examination, Articles 1, 2, 6, 7 and 23 (Section SE-797 only) Section IX, Welding and Brazing Qualifications
1/07 ITAC API 653 Exam Prep Homework #3 Questions Page 2
ITAC 51.
The letter “B” is placed on radiographic film holder for what reason? a. b. c. d.
To determine if back scatter radiation is exposing the film. To show the distance from the source of radiation to the weld. To function as a location marker for the radiograph. To designate whether the penetrameter (IQI) is on the film side or the back side.
Section: 52.
A tanks bottom course has corroded in a general uniform manner (including the welds). The tanks diameter is 137 and its height is 40 (5-eight foot courses). The liquid stored in the tank is hydrocarbon with a specific gravity of 0.82 and it is not corrosive. The tank was constructed from ASTM A-283, Grade C (A 283M, Grade C) carbon steel. Determine the minimum thickness of the bottom course for full height operation. Round to the nearest hundredth. (This tank was built to API 650, Eighth edition). a. b. c. d.
0.805” 0.691” 0.200” 0.483”
Section: 53.
Reference Publication:
A sudden rapid fracture under stress where the material exhibits little or no evidence of ductility or plastic deformation: a. b. c. d.
brittle fracture temper embrittlement thermal fatigue amine stress corrosion cracking
Section: 54.
Reference Publication:
Reference Publication:
A tank course made from 3/4” plate is welded with low hydrogen electrodes. The welder undercuts a horizontal butt weld to a depth of 0.02” and he reinforces the weld with a 0.20” reinforcement. a. b. c. d.
The weld is acceptable The weld is unacceptable because of the excess undercut The weld is unacceptable because of the excess reinforcement The weld is unacceptable because of the excess reinforcement and excess undercut
Section:
Reference Publication:
1/07 ITAC API 653 Exam Prep Homework #3 Questions Page 3
ITAC 55.
During a hot tap, what is the welding hazard commonly associated with welding on a tank that has held wet hydrogen sulfide? a. b. c. d.
Caustic cracking Chlorine shrinkage Steam blow out Pyrophoric scale
Section: 56.
How many tensile tests are required to qualify a 1/4” plate groove weld? a. b. c. d.
2 3 4 6
Section: 57.
100% 75% 50% 10%
Section:
Reference Publication:
The ___ number groupings are based essentially on the usability characteristics of welding electrodes. a. b. c. d.
A S F P
Section: 59.
Reference Publication:
A new bottom is installed in an existing tank, the annular plates are welded from one side using a backing bar, one spot radiograph shall be taken on _______ of the radial joints. a. b. c d.
58.
Reference Publication:
Reference Publication:
The acceptance criteria for a radiograph of a tank repair weld is found in a. b. c. d.
.
Section V of the ASME Code Section IX of the ASME Code Section VIII of the ASME Code ASNT SNT-TC-1A
Section:
Reference Publication:
1/07 ITAC API 653 Exam Prep Homework #3 Questions Page 4
ITAC 60.
All leaks in pontoons or compartments of double deck floating roofs shall be repaired by . a. b. c. d.
caulking the leaking joints and/or using soft patch material rewelding the leaking joints and/or the use of patch plates cutting out the leaking area and flush patching weld overlay any cracks and/or use soft patch material
Section: 61.
For what diameter tank is the variable point method for calculating shell thickness mandatory? a. b. c. d.
Tanks with a diameter of 200 feet and greater Tanks with a diameter greater than 300 feet Tanks with a diameter greater than 200 feet Tanks with a diameter of 300 feet and greater
Section: 62.
Reference Publication:
What is the minimum lifting power of an AC electromagnetic yoke used in magnetic particle inspection? a. b. c. d.
40 pounds lifting power at the maximum pole spacing 10 pounds lifting power at the maximum pole spacing 10 amps lifting power at the maximum pole spacing 30 pounds lifting power at the minimum pole spacing
Section: 63.
Reference Publication:
Reference Publication:
What is the allowable edge settlement of a 120 diameter tank that has an area of settlement that starts to slope 36” from the shell and the bottom lap weld is approximately parallel to the shell? a. b. c d.
13.32” 3.75” 18.5” 2.22”
Section:
Reference Publication:
1/07 ITAC API 653 Exam Prep Homework #3 Questions Page 5
ITAC 64.
A tank was constructed from welded ASTM A-516, Grade 60 (A 516M, Grade 415) steel. The third course must be evaluated for continued service. What is the allowable stress that must be used in the calculations? a. b. c. d.
21,300 25,560 28,200 28,320
Section: 65.
0.17” 0.20” 0.325” 0.295”
Section:
Reference Publication:
The principal advantage of thin-film linings are a. b. c. d.
.
better protection of older storage tank bottoms and ease of application less susceptible to mechanical damage and easier to repair lower cost and not as sensitive to pitting lower cost and ease of application compared to thick-film coating systems
Section: 67.
Reference Publication:
A 125 diameter X 40 high storage tank has questionable thickness annular plates. The first shell course thickness is .61”. The thickness of the corrosion allowance for the tank is 0.125”. The product specific gravity is less than 1. What is the minimum thickness for the annular plate? a. b. c. d.
66.
psi psi psi psi
Reference Publication:
In no case shall the internal inspection interval of an aboveground storage tank exceed _____ years, if an RBI program is not in place. a. b. c. d.
5 10 20 25
Section:
Reference Publication:
1/07 ITAC API 653 Exam Prep Homework #3 Questions Page 6
ITAC 68.
Welders who weld on tank shell butt welds are qualified to what standard or code? a. b. c. d.
Section VIII of the ASME Code Section V of the ASME Code Section I of the ASME Code Section IX of the ASME Code
Section: 69.
Reference Publication:
What is the maximum acceptable undercut of a nozzle to shell weld? a. b. c. d.
1/64” 1/32” 1/16” 1/8”
Section: 70.
Reference Publication:
A door sheet was cut in an existing tank . The shell is 1 5/8 inches thick at the door sheet location. a. b. c. d.
A minimum preheat of 200oF is required. A minimum preheat, warm to the hand, is required. Any temperature on the WPS is acceptable. No preheat is required.
Section: 71.
Reference Publication:
When a welder has not welded with a process during a period of _____, his qualifications for that process shall expire. a. b. c. d.
3 months or more 6 months or more 9 months or more 12 months or more
Section: 72.
Reference Publication:
What allowable stress is used in evaluating a riveted joint when using joint efficiencies given in Table 4-3 of API 653? a. b. c. d.
16,000 18,000 19,000 21,000
Section:
psi psi psi psi Reference Publication:
1/07 ITAC API 653 Exam Prep Homework #3 Questions Page 7
ITAC 73.
Radiographs of repaired work and records of radiographs of repaired work shall be marked with . a. b. c. d.
a grease pencil the mark of the welder who made the repair the letter “R” the initial of the inspector
Section: 74.
The transmitted film density through the radiographic image of the body of the appropriate hole penetrameter (IQI) and the area of interest shall be _____ minimum for radiographs made with a gamma ray source. a. b. c. d.
1.8 2.0 2.2 2.6
Section: 75.
Reference Publication:
Reference Publication:
A tank has a corroded area on its second course. It is elliptical in shape with the major axis parallel to the horizontal weld seam. The major axis dimension is 35” and the vertical minor axis is 21”. The tank diameter is 127 and its height is 40 (5-eight foot courses). The minimum thickness measured in the corroded area is 0.52. The general thickness of the second course (away from the corroded area) is 0.75”. What is the maximum critical length that can be used in determining the averaging out of the hoop stresses around the corroded area. Round to the nearest 0.1”. a. b. c. d.
40” 36.1” 30.1” 28.1”
Section:
Reference Publication:
1/07 ITAC API 653 Exam Prep Homework #3 Questions Page 8
Study Sheets Based on API 653 Exam Information The following is a collection of questions remembered by various students who took the API 653 Exam in the past. This study sheet is designed to help a student prepare for the API 653 Exam. Read each question carefully and select the best answer by circling your choice. After selection of your answer, write in the section number and publication in which your answer was found. Look up each question in the reference publications listed below; remember, this exercise is to help you to learn to use the reference material. Generally, the assignment is broken into several sections. Each section should take approximately one hour to complete. Answers will be discussed at the beginning of class the following morning. The answers will be found in the following reference publications: API 571, Damage Mechanisms Affecting Fixed Equipment in the Refining Industry, First Edition, December, 2003 ATTENTION: Only the following mechanisms are included in the exam: Par. 4.2.7 – Brittle Fracture Par. 4.2.16 – Mechanical Fatigue Par. 4.3.2 – Atmospheric Corrosion Par. 4.3.3 – Corrosion Under Insulation (CUI) Par. 4.3.8 – Microbiologically Induced Corrosion (MIC) Par. 4.3.9 – Soil Corrosion Par. 4.3.10 – Caustic Corrosion Par. 4.5.1 – Chloride Stress Corrosion Cracking (Cl-SCC) Par. 4.5.3 – Caustic Stress Corrosion Cracking (Caustic Embrittlement) Par. 5.1.1.11 – Sulfuric Acid Corrosion API RP 575, Guidelines and Methods for Inspection of Existing Atmospheric and Lowpressure Storage Tanks, Second Edition, May, 2005 API RP 577, Welding Inspection and Metallurgy, First Edition, October, 2004 API 650, Welded Steel Tanks for Oil Storage, Tenth Edition, November, 1998, including Addendum 1 (March, 2000), Addendum 2 (November, 2001), Addendum 3 (September, 2003) and Addendum 4 (December, 2005). API RP 651, Cathodic Protection of Aboveground Petroleum Storage Tanks, Third Edition, January, 2007 API RP 652, Lining of Above Ground Petroleum Storage Tank Bottoms, Third Edition, October, 2005 1/07 ITAC API 653 Exam Prep Homework #4 Questions Page 1
ITAC API 653, Tank Inspection, Repair, Alteration and Reconstruction, Third Edition, December, 2001, including Addendum 1 (September, 2003) and Addendum 2 (November, 2005). ASME Boiler & Pressure Vessel Code, 2004 Edition, with 2005 and 2006 Addenda Section V, Nondestructive Examination, Articles 1, 2, 6, 7 and 23 (Section SE-797 only) Section IX, Welding and Brazing Qualifications
1/07 ITAC API 653 Exam Prep Homework #4 Questions Page 2
76. What is the P number for the tank as listed above? a. b. c. d.
1.5 1 6 24
Section: 77.
Reference Publication:
If studs were installed on this tank, what polarity would have been used for the “stud gun”? a. b. c. d.
DCEN DCEP AC No polarity
Section:
Reference Publication:
1/07 ITAC API 653 Exam Prep Homework #4 Questions Page 3
ITAC 78.
What is the SFA number for E 7018 electrodes? a. b c. d.
5 5.1 5.29 5.42
Section: 79.
What is the filler number for E-7018 electrodes? a. b. c. d.
1 2 3 4
Section: 80.
.316” .500” .262” Not enough information given
Section:
Reference Publication:
What is the hydrostatic test height of T 3-27 if the joint efficiency is .85 and the specific gravity of the product is 1.3? a. b. c. d.
56.88' 40' 28.27' Not enough information given
Section: 82.
Reference Publication:
What is the minimum acceptable shell plate thickness for the first course of T 3-27, if the specific gravity of the stored product is 1.3? NOTE: current inspection (2003) based on product alone, and full height operation. a. b. c. d.
81.
Reference Publication:
Reference Publication:
What is the minimum acceptable shell plate thickness for the top course of T 3-27 if each course is 120" tall? a. b. c. d.
.1" .062" .269" Not enough information given
Section:
Reference Publication: 1/07 ITAC API 653 Exam Prep Homework #4 Questions Page 4
ITAC 83.
What is the joint efficiency for T 3-27? a. b. c. d.
1 .85 .70 .35
Section: 84.
What is the corrosion allowance for T 3-27? a. b. c. d.
.185" .125" .0625" Not enough information given
Section: 85.
.269" .310" .500" Not enough information given
Section:
Reference Publication:
How many settlement points are required for an external settlement of T 3-27? a. b. c. d.
4 6 8 10
Section: 87.
Reference Publication:
If T 3-27 was new, what would be the minimum first course thickness, based on product alone? a. b. c. d.
86.
Reference Publication:
Reference Publication:
A depression in the floor is discovered near the east manway of T 3-27. The diameter of the depression is 96", the deepest point in the depression is 4". The area _________. a. b. c. d.
is rejectable. is acceptable. must be monitored. can be filled in with epoxy and accepted.
Section:
Reference Publication: 1/07 ITAC API 653 Exam Prep Homework #4 Questions Page 5
ITAC 88.
During the internal inspection of T 3-27, a patch plate welded to the floor, with a tombstone shaped pad, extending to the inside of the shell was discovered. The plate had been seal welded to the floor and shell, with a minimum dimension of 12 inches. The inspector should _____________. a. b. c. d.
have the patch removed. inspect the patch. recommend removal of the patch and floor plates in the repaired area, replacing with new floor plates. this repair is in the critical zone and not allowed.
Section:
89.
During the same internal inspection of T 3-27, a square lap-welded patch was found over an existing nozzle. The inspector should __________. a. b. c. d.
have the patch removed. inspect the patch. cut out the entire shell plate. radiograph the patch for weld quality.
Section: 90.
Reference Publication:
T 3-27 has a hole, less than 1" in diameter, in the roof. Rain water does not contaminate the stored product. Is a repair required by API 653? a. b. c. d.
A repair may be made by using duct tape. Only if the owner requires the repair. No Yes
Section: 91.
Reference Publication:
Reference Publication:
What is the position designation for welding pipe in the horizontal fixed position? a. b. c. d.
2G 3G 5G 6G
Section:
Reference Publication:
1/07 ITAC API 653 Exam Prep Homework #4 Questions Page 6
ITAC 92.
What is the minimum remaining thickness of a floor using the following conditions.
0r = 10 years RTbc = .200” RTip = .190” a. b. c. d.
.200” .190” .120” .100”
Section: 93.
Weld reinforcement Good weld technique Weld toe Weld throat
Section:
Reference Publication:
If T 3-27 had a new nozzle installed in the third course, north side, could the shell-to-nozzle weld be made using the oxyfuel welding process, if impact testing is not required? a. b. c. d.
Yes No The oxyfuel process is not allowed by ASME Section IX Nozzle welds must be made using SMAW only
Section: 95.
Reference Publication:
Terminology for weld metal in excess of the specified weld size. a. b. c. d.
94.
S tPr = 0 (the inside has been coated) UPr = .007
Reference Publication:
A circular insert replacement plate was installed on an existing tank. How many radiographs are required if the shell is 5/8” thick where the plate is installed? a. b. c. d.
1 4 None, if the thickness is less than 1 inch None
Section:
Reference Publication:
1/07 ITAC API 653 Exam Prep Homework #4 Questions Page 7
ITAC 96.
The minimum lbf/in2 for a vacuum box test is a partial vacuum of ____ gauge. a. b. c. d.
1 lbf /in2 2 lbf /in2 3 lbf /in2 4 lbf /in2
Section: 97.
A pipe welder is qualified to API 1104 only. What welds can he make on the tank if he is qualified in the 6G position? a. b. c. d.
Nozzle Welds Shell Welds Floor and roof fillet welds None
Section: 98.
1" 1/2" 1/4" 1/8"
Section:
Reference Publication:
A procedure is qualified on plate .500" thick. Four nick break specimens were substituted for the four side bends. a. b. c. d.
The procedure is qualified. ASME does not allow nick breaks. Two tension specimens were required. Nick breaks are used only on pipe.
Section: 100.
Reference Publication:
A procedure is qualified on plate .500" thick. Which of the following thicknesses is not qualified? a. b. c. d.
99.
Reference Publication:
Reference Publication:
A welder is qualified in the 3F and 4F positions. Which of the following groove welds can he make? a. b. c. d.
1G 2G 6G None
Section:
Reference Publication: 1/07 ITAC API 653 Exam Prep Homework #4 Questions Page 8
ITAC Visit our website: www.itac.net
Inspection Training And Consulting Post Office Box 5666 Pasadena, TX 77508-5666 Phone: 281-998-8305 Fax: 281-998-2163
Lap Patches Considerations: Does the owner prohibit the use of a lap patch? (Para. 9.3.1) Will the repair prevent gas freeing the tank to perform hot work, at a later date? (Para. 9.3.4.5) Will crevice corrosion or a corrosion cell between the shell plate and repair plate likely occur? (Para. 9.3.4.4) An affirmative answer to any of the above is cause to stop planning on a lap patch. Since the inception of API 653, Tank Inspection, Repair, Alteration, And Reconstruction, the fillet weld lap patch has been prohibited, until the Second Edition, 1995, First Addenda, 1996. The owner/user may now use paragraph 9.3, “Shell Repairs Using Lap Welded Patch Plates” under certain conditions and size limitations. The first 11 paragraphs apply to lap patches generally. 1.
The lap patch is considered a permanent repair and subject to ongoing inspection and maintenance. (Para. 9.3.1)
2.
All the repair material must conform to the requirements of API 653, which will reference API 650, Welded Steel Tanks for Oil Storage.
3.
A lap patch may not be used on any shell course thickness that exceeds 1/2 inch or to replace doorsheets or shell plates. (Para 9.3.1.2)
4.
Patch plates may be from 3/16 to 1/2 inches thick, depending to the thickness of the shell plate to be repaired. (Para. 9.3.1.3)
5.
The repair plate may be circular, oblong, square, or rectangular with rounded corners, except at the shell to bottom joint. The radius of the corners shall be 2 in. minimum. (Para. 9.3.1.4)
6.
The butt welded seams that are covered, by the patch, must be ground flush and must over lap a minimum of 6 inches, use Figure 9-1 as a guide. (Para. 9.3.1.5)
Figure 9-1 is on the next page.
ITAC Notes on Patch Plates, 2003 Page 1
Figure 9-1 - Acceptable Details for Replacement of Shell Plate Material
ITAC Notes on Patch Plates, 2003 Page 2
7.
Refer to Figure 9-2 for details on welding the lap patch to the shell to bottom joint. Note: An internally installed patch must be located such that the toe-to-toe weld clearances are a minimum of 6 inches to the shell to bottom weld. (Para. 9.3.1.6)
T
T Tank Shell
W
3/16 Repair Plate
W
3/16
Trim repair plate to clear Shell-to-bottom weld
8.
The maximum size of a patch plate is 48 inches by 72 inches, the minimum size is 4 inches. The patch shall be formed to the shell radius. (Para. 9.3.1.7)
9.
Shell openings and reinforcements shall not be positioned within a lapped patch shell repair. (Para. 9.3.1.8)
10.
An ultrasonic inspection for laminations and other plate defects shall be performed on the shell plate in the areas to be welded. (Para. 9.3.1.9)
11.
Repair plates shall not be lapped on lap welded shell seams, riveted shell seams, other lapped patch repair plates, distorted areas, or unrepaired cracks or defects. (Para. 9.3.1.10)
ITAC Notes on Patch Plates, 2003 Page 3
The next 5 paragraphs apply to the use of lap patches to close holes in the shell. 12.
A lap patch may be used for the closure of holes, where openings have been removed or the removal of severely corroded/eroded areas, but there are special requirements. (Para. 9.3.2)
13.
The weld shall be continuous on the inside and outside of the patch plate, the removed opening must be at least 2 inches in diameter, a minimum corner radius of 2 inches is required for plate removal. (Para. 9.3.2.1)
14.
Nozzles and reinforcement pads must be removed entirely before the repair plate is installed. (Para. 9.3.2.2)
15.
Repair plates, for opening repairs, shall be of a design that conforms to API 653, using a joint efficiency not exceeding 0.70. All fillet welds shall be full (equal leg) fillet welds. The overlap of the repair plate shall not exceed 8 times the shell thickness, minimum overlap is 1 inch. The minimum repair plate dimension shall be 4 in. (Para. 9.3.2.3)
16.
The repair plate shall not exceed the nominal thickness of the shell plate adjacent to the repair. (Para. 9.3.2.4)
The next 4 paragraphs apply to the use of lap patches to repair areas of thinned shells due to deterioration. 17.
Lap patches may be used to reinforce areas of deteriorated shell plates and to reinforce shell plates that are below retirement thickness. (Para. 9.3.3)
18.
The repair plate thickness shall be based on API 653, using a joint efficiency not exceeding 0.35, the perimeter weld shall be full fillet (equal leg) weld. (Para. 9.3.3.1)
19.
The repair plates for this repair shall not exceed 1/2 inch thick, only a 1/8 in thicker repair plate than the existing shell plate is allowed. (Para. 9.3.3.2)
20.
The remaining strength of the deteriorated areas under the repair plate shall not be considered as effective in carrying the calculated service or hydrotest loads. (Para. 9.3.3.3)
The next 4 paragraphs apply to the use of lap patches to repair leaks or potential leaks in the shell. 21.
Lap patches may be used to repair leaks or minimize the potential leaks form pitting. (Para. 9.3.4)
22.
To install a lap patch over a leak, the existing shell thickness, excluding holes and pits, must meet the minimum acceptable shell thickness (t min.). (Para. 9.3.4.1)
23.
The repair plate must be designed to withstand the hydrostatic pressure load between the repair plate and the shell assuming a hole exists in the shell using a joint efficiency of 0.35. (Para. 9.3.4.2)
24.
The repair plates for this repair shall not exceed 1/2 inch thick, only a 1/8 in thicker repair plate than the existing shell plate is allowed. A full (equal leg) fillet perimeter weld is required. (Para. 9.3.4.3) ITAC Notes on Patch Plates, 2003 Page 4
The last 3 paragraphs apply to safety warnings and inspection requirements of lap patches. 25.
Do not use a lap patch if corrosion between the shell plate and repair plate is likely to occur. (Para. 9.3.4.4)
26.
Do not use a lap patch if the repair plate will prevent gas freeing the tank to perform future hot work, remember a penetration is not allowed in the patch. (Para. 9.3.4.5)
27.
Future inspection must be performed on the patch plates. (Para. 9.3.4.6)
ITAC Notes on Patch Plates, 2003 Page 5
ITAC Notes on Patch Plates, 2003 Page 6
ITAC
Inspection Training And Consulting
Post Office Box 5666 Pasadena, TX 77508-5666 Phone: 281-998-8305 Fax: 281-998-2163
Visit our website www.itac.net Name:
API 653/650 Math Review Quiz Answer each question, show all work, circle your final answer. 1.
Add: 1' 4 1/2" + 3' 5 11/32" + 10' 6 5/8" =
2.
Subtract:
3.
Solve:38" = ____ feet
4.
Express 7/16" as a decimal fraction _____
5.
Solve for A: A = 11 X 24 - (45 + 6)3
6.
What is the Square Root of 1849?
7.
What is the radius of a circle whose diameter is 182'?
287' - 3' 4 15/16" =
API 653 Math Review Quiz 01/05
Page 1
ITAC 8.
What is the area of the circle in Question 7 ?
9.
10" = ____ mm
10.
1/4” = ____ mm
11.
200’ = ____ m
12.
Solve for Z: 296 = 10(Z+6)
13.
Solve for t t=
2.6 X 50 (41-1) X .85 + .125 20,000
API 653 Math Review Quiz 01/05
Page 2
ITAC 14.
Solve for t t=
2.6 X 80 (30-1) 26,300
15.
An inspection is performed on an existing AST 67' tall, 190' in diameter with a fill height of 60'. What is the minimum thickness of the first course, based on product alone, if the specific gravity of the product is .8?
16.
What is the minimum thickness of the fourth course of the tank in question 15, if each course is 5' high?
API 653 Math Review Quiz 01/05
Page 3
ITAC 17.
In performing a settlement survey on a tank 100’ in diameter, what spacing should be used for survey reference?
18.
What is the design first course thickness of a new tank that is 60' tall, fill height of 58', diameter of 90', the material is A 516M Grade 485, the corrosion allowance is .125" and the specific gravity of the stored product is 1?
API 653 Math Review Quiz 01/05
Page 4
ITAC 19.
What is the hydrostatic test first course thickness of the new tank in question 18?
20.
What is the annular plate thickness of the new tank in question 18, if an annular plate is required?
API 653 Math Review Quiz 01/05
Page 5
ITAC 21.
What is the minimum thickness of the first course of an existing tank if the nameplate reads as follows: Height: 40' Diameter: 60' Year Completed: 1990 All Courses: A516-70 Specific Gravity: 1.3
API 653 Math Review Quiz 01/05
Page 6
nspection raining nd onsulting Post Office Box 5666 Pasadena, TX 77508-5666 Phone (281) 998-8305 Fax (281) 998-2163
Visit our website "www.itac.net".
1. 2. 3. 4. 5. 6. 7. 8.
2 1 3 3 1 2 2 3
(Page 95, Par. T-620) ASME V (Page 13, Par. QW-200.1a) ASME IX (Page 150, Par. QW-461.9) ASME IX (Page 22, Par. QW-252) ASME IX (Page 53, Par. QW-304) ASME IX (Page H-4, Par. H.4.4.3) API 650 (Page 107, Par. T-752.3) ASME V (Page 11-1, Par. 11.1.1) API 653 (Page 7-2, Par. 7.3.2) API 650 9. 1 (Page 10, Par. T-274.2) ASME V 10. 3 (Page 388, Par. 1.1) ASME V 11. 2 (Page 109, Par. T-761(a) ASME V 12. 1 (Page 109, Par. T-761(c) ASME V 13. 1 (Page 15, Par. T-284) ASME V 14. 3 (Page 12-1, Par. 12.1.2.1) API 653 15. 2 (Page 4-3, Par. 4.3.2.2) API 653 16. 4 (Page 4-3, Par. 4.3.3.1) API 653 Solution: Use the formula, Minimum Thickness Calculation for Welded Tank Shell: tmin= 2.6 (H-1)DG SE tmin=
2.6 (22-1) (94)(1) 23,600
tmin=
5,132.4 23,600
tmin=
.217"
Values substituted
17. 1 (Page 4-3, Par. 4.3.3.1) API 653 Solution: Use the formula, Minimum Thickness Calculation for Welded Tank Shell. tmin= 2.6 (H-1)DG SE tmin=
2.6 (14-1) (94)(1) 26,000(1)
tmin=
3,177.2 26,000
tmin=
.122
Values substituted
18. 2 (Page 4-2, Par. 4.3.2) API 653 Solution: Use the formula, Actual Thickness Determination. L = 3.7 √ (Dt2) L = 3.7 √ (94) (.125)
Values substituted
L = 3.7 √ (11.75) L = 3.7 X 3.428 L = 12.68" 19. 4 (Page 4-3, Par. 4.3.2.2b) API 653 Solution: Use the Pit Measurement Technique. d1 + d2 + d3 ... < 2" 1.250 + 1 + .500 = 2.750"
Values substituted
20. 1 (Page 4-3, Par. 4.3.2.2a) API 653 21. 2 (Page B-7, Par. B.3.3) API 653 22. 4 (Page B-9, Fig. B-10) API 653 23. 1 (Page 4-5, Par. 4.3.3.2) API 653 Solution: Use the formula, Hydrostatic test height for welded tank shells. Ht = StE tmin +1 2.6D+1 St = 26,000 (From Table 4-1) Ht = (26,000) (1) (.218) +1 2.6(94) Ht = 5668 244.4
+1
Ht = 23.19 + 1 Ht = 24.19 (Rounded to 24)
Revised 01/07
24. 1 (Page B-7, Par. B.3.3) API 653 Solution: Use the formula: BB = 0.37R BB = 0.37 (1.5) Values substituted BB =
29. 4 (Page 4-5, Par. 4.3.3.2) API 653 Solution: Use the formula, Hydrostatic test height for welded tank shells. Ht = StE tmin +1 2.6D St = 33,000 (From Table 4-1)
.555" (Fig. B-9, same answer)
Ht = (33,000) (1) (.197) 2.6(82)
25. 2 (Page 4-3, Par. 4.3.3.1) API 653 Solution: Use the formula, Minimum Thickness Calculation for Welded Tank Shell. tmin=
tmin=
tmin=
tmin=
Ht = 6501 213.2
2.6 (H-1)DG SE 2.6 (17-1) (94)(1) 23,600(1)
Ht = 31.49’ or (approx. 31’ 6")
Values substituted
3,910.4 23,600 .166"
30. 31. 32. 33. 34. 35. 36. 37. 38. 39.
2 2 1 3 4 3 3 1 1 2
MRT = RTbc - Or(StPr + UPr)
(Pg 109, Par T-762(b)) ASME Sec V, Art 7 (Pg 109, Par T-762(c)) ASME Sec V, Art 7
(Page 3-6, Par. 3.5.3) API 650 (Page 9-7, Par. 9.10.1.2 (b)) API 653 (Pg 22, Par. QW-253) ASME Sec IX (Pg 9, Par. QW-194) ASME Sec IX (Page 3-7, Par. 3.6.3) API 650
Tt = 2.6 X 150 (40-1) 24,900
27. 2 (Page 4-9, Par. 4.4.7.1) API 653 Solution: Use the formula, Minimum Thickness for Tank Bottom Plate.
Tt = 390 (39) 24,900
MRT = RTip - Or(StPr + UPr)
Tt = 15,210 24,900
MRT = .190 - 10(.002 + .010) Values substituted MRT = .190 - 10(.012) MRT = .190 - .12 MRT = .070 (Pg 7, Par T-222.2) ASME Sec V
(Pg 13, Tbl T-276)) ASME Sec V, Art 2 (Pg 96, Par T-652) ASME Sec V, Art 6 (Pg 112, Par T-774) ASME Sec V, Art 7
Tt = 2.6D(H-1) St
MRT = .200 - 10(.002 + .010) Values substituted MRT = .200 - 10(.012) MRT = .200 - .12 MRT = .080
4
+1
Ht = 30.49' +1
26. 4 (Page 4-9, Par. 4.4.7.1) API 653 Solution: Use the formula, Minimum Thickness for Tank Bottom Plate.
28.
+1
Tt = 0.611 (round to .625 plate) 40. 41. 42. 43.
4 3 2 1
(Page 6-3, Par. 6.1.3.4) API 650 (Page 35, Par. 7.2.10) API 575 (Page C-1, Par. C.3.4.1) API 650 (Page 4-19, Par. 4.2.7.1) API 571 Revised 01/07
44. 45. 46. 47. 48. 49. 50. 51. 52. 53. 54. 55. 56. 57. 58. 59. 60. 61. 62. 63. 64. 65. 66. 67. 68. 69. 70. 71. 72. 73. 74. 75. 76. 77. 78. 79. 80. 81. 82. 83. 84. 85. 86. 87. 88. 89. 90. 91. 92. 93. 94.
4 2 4 2 2 2 2 2 2 3 3 2 1 3 3 1 3 2 1 3 1 2 4 4 2 3 2 4 4 3 2 2 1 2 3 3 3 1 1 4 1 3 4 4 1 3 1 2 3 2 1
(Page G-2, Par. G.4.4) API 653 (Page G-1, Par. G.2.5) API 653 (PQR and WPS (PQR and WPS) (QW-451.1, Pg. 138) ASME Sec. IX (QW-451.1, Pg. 138) ASME Sec. IX (QW-451.1, Pg. 138) ASME Sec. IX (Page 1-1, Par. 1.2) API 653 (Page 17, Par. 5.4) API 575 (Page 4-95, Par. 4.3.10.1) API 571 (Page 6-1, Par. 6.3.2.1) API 653 (Page 6-1, Par. 6.3.1.1) API 653 (Page 3-1, Par. 3.9) API 653 (Page 34, Par. 7.2.9) API 575 (Page 24, Par. 11.3.2.2) API 651 (Page 2, Par. 3.3) API 577 (Page 11-1, Par. 11.1.1) API 653 (Page 5-4, Par. 5.3.6.1) API 650 (Page 4-1, Par. 4.2.1.2) API 653 (Page 2, Par. 3.7) API 577 (Page 7-2, Par. 7.3.1) API 650 (Page 3, Par. 3.29) API 577 (Page 4-69, Par. 4.3.2.1) API 571 (Page 5, Par. 4.2.3) API 575 (Page C-1, Par. C.3.3.3) API 650 (Page 57, Par. 9.3) API 575 (Page 6-2, Par. 6.4.2.2) API 653 (Page 3, Par. 3.45) API 577 (Page 4-10, Par. 4.5.1.2a) API 653 (Page 6-2, Par. 6.4.2.1) API 653 (Page 5-4, Par. 5.3.4) API 650 (Page 4, Par. 3.70) API 577 (Page 7-1, Par. 7.3.1.2) API 653 (Page 4, Par. 3.67) API 577 (Page 3-1, Par. 3.10) API 653 (Page 3-6, Par. 3.5.2) API 650 (Page 7-1, Par. 7.3.1.3) API 653 (Page 4-6, Par. 4.3.5.3) API 653 (Page 6-1, Par. 6.3.1.2) API 653 (Page 4, Par. 3.52) API 577 (Page 6-3, Table 6-1) API 653 (Page 6-1, Par. 6.3.3.2) API 653 (Page 3, Par. 3.47) API 577 (Page 17, Par. 5.4) API 575 (Page D-1, Par. D.2.1a) API 653 (Page 5-1, Par. 5.2.1.4) API 650 (Page 6-1, Par. 6.3.3.2) API 653 (Page 8-1, Par. 8.2.2) API 653 (Page 4, Par. 3.54) API 577 (Page 3-1, Par. 3.1.1.1) API 650 (Page 4-1, Par. 4.2.4.3) API 653
95. 96. 97. 98. 99. 100. 101. 102. 103. 104. 105. 106. 107. 108. 109. 110. 111. 112. 113. 114. 115. 116. 117. 118. 119. 120. 121. 122. 123. 124. 125. 126. 127. 128. 129. 130. 131. 132. 133. 134. 135. 136. 137. 138. 139. 140. 141. 142. 143. 144.
2 1 2 1 3 1 1 4 3 3 4 2 2 4 2 1 3 3 3 1 2 2 2 4 4 1 2 4 2 4 3 2 2 1 1 2 1 3 2 1 2 3 4 2 4 3 1 2 3 4
(Page 3-13, Par. 3.7.2.1) API 650 (Page 1-1, Par. 1.1.3) API 653 (Page G-2, Par. G.5.1.1) API 653 (Page 2, Par. 3.15) API 577 (Page 6-3, Par. 6.1.5) API 650 (Page 10-4, Par. 10.5.5) API 653 (Page 2, Par. 3.17) API 577 (Page 3-1, Par. 3.1) API 653 (Page 6-3, Par. 6.1.2.9b) API 650 (Page 10-3, Par. 10.4.4.1) API 653 (Page 2, Par. 3.3) API 575 (Page 2, Par. 3.18) API 577 (Page 3, Par. 3.51) API 577 (Page 11-1, Par. 11.2.2) API 653 (Page 3-6, Par. 3.5.2) API 650 (Page 12-3, Par. 12.2.1.8) API 653 (Page 8, Par. 4.6) API 577 (Page 1-1, Par. 1.1.1) API 650 (Page 9-9, Par. 9.10.2.2) API 653 (Page 13-1, Par. 13.1.2) API 653 (Page 6-1, Par. 6.3.3.2b) API 653 (Page 8-1, Par. 8.4.1) API 653 (Page 8-1, Par. 8.4.2) API 653 (Page 9, Par. 5.1) API 577 (Page 9-5, Par. 9.8.6) API 653 (Page 1-3, Par. 1.3) API 650 (Page B-4, Par. B.2.3.1) API 653 (Page 12-3, Par. 12.3.2.1b) API 653 (Page B-1, Par. B.2.2.2) API 653 (Page 11, Par. 5.4.1) API 577 (Page 9-6, Par. 9.11.1.1) API 653 (Page 3, Par. 3.25) API 652 (Page 9-9, Par. 9.10.2.1.1) API 653 (Page 9-1, Par. 9.1.1) API 653 (Page 8-1, Par. 8.2.2) API 653 (Page 12-2, Par. 12.2.1) API 653 (Page 17, Par. 5.4) API 575 (Page 10-1, Par. 10.2) API 653 (Page 3-6, Par. 3.4.1) API 650 (Page 3-1, Par. 3.13) API 653 (Page 5-5, Par. 5.4.4) API 650 (Page 12-3, Par. 12.3.1a) API 653 (Page 5-2, Par. 5.2.3.1) API 650 (Page 12-5, Par. 12.4) API 653 (Page 6-4, Par. 6.3.2.5) API 650 (Page 3-50, Par. 3.10.4.6) API 650 (Page 8-1, Par. 8.1) API 653 (Page 2, Par. 3.2) API 651 (Page 2, Par. 3.6) API 651 (Page 3, Par. 3.22) API 652 Revised 01/07
145. 146. 147. 148. 149. 150.
3 2 4 2 1 4
(Page 6, Par. 4.2.2) API 651 (Page 14, Par. 6.2.1) API 651 (Page 6-1, Par. 6.3.2.1) API 653 (Page 7-1, Par. 7.4) API 653 (Forward Page iii) API 653 (Page 3-1, Par. 3.15) API 653
Revised 01/07
ITAC
Inspection Training And Consulting
Post Office Box 5666 Pasadena, TX 77508-5666 Phone: 281-998-8305 Fax: 281-998-2163
Visit our website www.itac.net Name:
API 653/650 Math Review Quiz (Answer Key) Answer each question, show all work, circle your final answer. 1.
Add: 1' 4 1/2" + 3' 5 11/32" + 10' 6 5/8" = 15' 4 15/32" Solution:
2.
3.
4.
Subtract:
287' - 3' 4 15/16" = 283' 7 1/16"
Solution:
287' = 286' 11 16/16" - 3' 4 15/16" 283' 7 1/16"
Solve:
38" = _3' 2" or 3.167 ___ feet
Solution:
(1' = 12")
38 ÷ 12 = 3' 2" or 3.16'
Express 7/16" as a decimal fraction ___.438"__ Solution:
5.
1' 4 1/2" = 1' 4 16/32 3' 5 11/32" = 3' 5 11/32 10' 6 5/8" = 10' 6 20/32 14' 15 47/32" = 15' 4 15/32"
7/16 = 7 ÷ 16 = .438"
Solve for A: A = 11 X 24 - (45 + 6)3 Solution:
A = 11 X 24 - (45 + 6)3 A = 11 X 24 - (51)3 A = 11 X 24 - 153 A = 264 - 153 A = 111
6.
What is the Square Root of 1849? ____ Solution: 1849 = 43
7.
What is the radius of a circle whose diameter is 182'? Solution:
(Radius = Diameter ÷ 2) R = 182 ÷ 2 = 91'
API 653 Math Review Quiz 01/05 Key
Page 1
ITAC 8.
What is the area of the circle in Question 7 ? Solution:
9.
(Area of a circle = r2 ) A = (3.1416) (912 ) A = (3.1416) (8281) A = 26,015.589 Sq. Ft.
10" = __254__ mm Solution:
(1" = 25.4 mm) 10 X 25.4 = 254 mm
10.
1/4” = __6__ mm Solution:
(1" = 25.4 mm) .25 X 25.4 = 6.35 mm (API rounded to 6 mm)
11.
200’ = __60__ m Solution:
(1’ = .3 m) 200 X .3 = 60 m
12.
Solve for Z: Solution:
296 = 10(Z+6) 296 = 10(Z+6) 10 10 29.6 = Z+6 29.6 - 6 = Z + 6 - 6 23.6 = Z
13.
Solve for t t=
2.6 X 50 (41-1) X .85 + .125 20,000
t=
2.6 X 50 (40) X .85 20,000
t=
4420 20,000
t=
.221 + .125
t=
.346
+ .125
+ .125
API 653 Math Review Quiz 01/05 Key
Page 2
14.
15.
ITAC
Solve for t t=
2.6 X 80 (30-1) 26,300
t=
2.6 X 80 (29) 26,300
t=
6032 26,300
t=
.229
An inspection is performed on an existing AST 67' tall, 190' in diameter with a fill height of 60'. What is the minimum thickness of the first course, based on product alone, if the specific gravity of the product is .8? Solution: Use the formula, Minimum Thickness Calculation for Welded Tank Shell, from API 653, page 4-3, paragraph 4.3.3.1. tmin= 2.6 (H-1)DG SE tmin= 2.6 (60-1) (190) (.8) 23,600 (1)
Values substituted
tmin= 2.6(59)(190).8 23,600 tmin= 23,316.8 23,600 tmin= .988" 16.
What is the minimum thickness of the fourth course of the tank in question 15, if each course is 5' high? Solution: Use the formula, Minimum Thickness Calculation for Welded Tank Shell, from API 653, page 4-3, paragraph 4.3.3.1. tmin= 2.6 (H-1)DG SE tmin= 2.6 (45-1) (190) (.8) 26,000 (1)
Values substituted
tmin= 2.6(44)(190).8 26,000 tmin= 17,388.8 26,000 tmin= .669" API 653 Math Review Quiz 01/05 Key
Page 3
ITAC 17.
In performing a settlement survey on a tank 100’ in diameter, what spacing should be used for survey reference? Solution:
N = D ÷ 10 N = 100 ÷ 10 N = 10
N = minimum required number of settlement measurement points
C=D C = (3.1416) (100) C = 314.16
Perimeter of the tank
314.16 ÷ 10 = 31.416 feet apart API 653 requires no more than 32 feet between measurement points, an additional point is not required. 18.
What is the design first course thickness of a new tank that is 60' tall, fill height of 58', diameter of 90', the material is A 516M Grade 485, the corrosion allowance is .125" and the specific gravity of the stored product is 1.? Solution: Use the formula, 1-Foot Method from API 650, page 3-7, paragraph 3.6.3. td =
2.6 D (H-1) X G Sd
+ CA
td =
2.6 X 90 (58-1) X 1 25,300
+ .125
td =
2.6 X 90 (57) X 1 25,300
+ .125
td =
13,338 25,300
td =
.527
td =
.652"
+ .125
+ .125
API 653 Math Review Quiz 01/05 Key
Page 4
ITAC 19.
What is the hydrostatic test first course thickness of the new tank in question 18? Solution: Use the formula, 1-Foot Method from API 650, page 3-7, paragraph 3.6.3.
20.
tt =
2.6 D (H-1) St
tt =
2.6 X 90 (58-1) 28,500
tt =
2.6 X 90 (57) 28,500
tt =
13,338 28,500
tt =
.468"
What is the annular plate thickness of the new tank in question 18, if an annular plate is required? Solution: Use the formula, in Table 3-1 and paragraph 3.5.3 from API 650, page 3-6. Hydrostatic Test Stress =
2.6 D (H-1) t
Hydrostatic Test Stress =
2.6 X 90 (58-1) .652
Hydrostatic Test Stress =
2.6 X 90 (57) .652
Hydrostatic Test Stress =
13,338 .652
Hydrostatic Test Stress =
20,457
1/4" required + CA (.125) = .375"
API 653 Math Review Quiz 01/05 Key
Page 5
ITAC 21.
What is the minimum thickness of the first course of an existing tank if the nameplate reads as follows: Height: 40' Diameter: 60' Year Completed: 1990 All Courses: A516-70 Specific Gravity: 1.3 Solution: Use the formula, Minimum Thickness Calculation for Welded Tank Shell, from API 653, page 4-3, paragraph 4.3.3.1. tmin= 2.6 (H-1)DG SE tmin= 2.6 (40-1) (60) (1.3) 30,000 (1)
Values substituted
tmin= 2.6(39)(60) (1.3) 30,000 tmin= 7,909.3 30,000 tmin= .264"
API 653 Math Review Quiz 01/05 Key
Page 6
ITAC API 653/650 Math Review Quiz (Useful Circle Formulas) Area of a Circle = pi (3.1416) X radius2 or A = r2 Circumference = pi (3.1416) X Diameter or C = D Radius = Diameter ÷ 2 or
R=D 2
Circumference
Diameter
Radius
API 653 Math Review Quiz 01/05 Key
Page 7
ITAC API 653/650 Math Review Quiz (API Metrics) 1/4” 5/16” 3/8” 7/16” 1/2” 9/16” 5/8” 11/16 3/4” 13/16 7/8” 15/16 1”
= = = = = = = = = = = = =
6 mm 8 mm 10 mm 11 mm 12.5 mm 14 mm 16 mm 18 mm 20 mm 21 mm 22 mm 24 mm 25 mm
The above information taken from API 650, page 3-19.
API 653 Math Review Quiz 01/05 Key
Page 8
Visit our website www.itac.net NAME:
DATE: A S NS ON STTIIO ES UE QU M 22000077 Q AM XA EX PII 665533 E AP ((S Seelleecctt TThhee B weerr)) Annssw Beesstt A
TThhee ffiirrsstt ppaarrtt ooff tthhee eexxaam Booookk,,"" m iiss ""O Oppeenn B ffeeeell ffrreeee ttoo uussee aannyy ooff tthhee ffoolllloow wiinngg:: Use the following reference publications only on the “open book” portion of this practice exam: API 571, Damage Mechanisms Affecting Fixed Equipment in the Refining Industry, First Edition, December, 2003 ATTENTION: Only the following mechanisms are included in the exam: Par. 4.2.7 – Brittle Fracture Par. 4.2.16 – Mechanical Fatigue Par. 4.3.2 – Atmospheric Corrosion Par. 4.3.3 – Corrosion Under Insulation (CUI) Par. 4.3.8 – Microbiologically Induced Corrosion (MIC) Par. 4.3.9 – Soil Corrosion Par. 4.3.10 – Caustic Corrosion Par. 4.5.1 – Chloride Stress Corrosion Cracking (Cl-SCC) Par. 4.5.3 – Caustic Stress Corrosion Cracking (Caustic Embrittlement) Par. 5.1.1.11 – Sulfuric Acid Corrosion API RP 575, Guidelines and Methods for Inspection of Existing Atmospheric and Lowpressure Storage Tanks, Second Edition, May, 2005 API RP 577, Welding Inspection and Metallurgy, First Edition, October, 2004 API 650, Welded Steel Tanks for Oil Storage, Tenth Edition, November, 1998, including Addendum 1 (March, 2000), Addendum 2 (November, 2001), Addendum 3 (September, 2003) and Addendum 4 (November, 2005). API RP 651, Cathodic Protection of Aboveground Petroleum Storage Tanks, Second Edition, December, 1997 API RP 652, Lining of Above Ground Petroleum Storage Tank Bottoms, Third Edition, October, 2005 API 653, Tank Inspection, Repair, Alteration and Reconstruction, Third Edition, December, 2001, including Addendum 1 (September, 2003) and Addendum 2 (November, 2005). ITAC API 653 Practice Exam
Page 1
ITAC ASME Boiler & Pressure Vessel Code, 2004 Edition, with 2005 Addenda Section V, Nondestructive Examination, Articles 1, 2, 6, 7 and 23 (Section SE-797 only) Section IX, Welding and Brazing Qualifications
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ITAC API 653 Practice Exam
Page 2
A S NS ON STTIIO ES UE QU M 22000077 Q AM XA EX PII 665533 E AP O Booookk Oppeenn B 1.
The liquid penetrant examination method is an effective means for detecting 1. 2. 3. 4.
2.
3.
Flat and horizontal Horizontal and vertical Flat and vertical Vertical and overhead
A change in groove design A change in backing A change in post weld heat treatment A change in electrode angle
A welder may be qualified by RT if 1. 2. 3. 4.
6.
provide direction for making production welds to Code requirements provide direction for the welder to make temporary welds provide direction for the inspector for inspection of the welds provide direction for the welder to use as a general guideline
Which of the following is an essential variable for the WPS? 1. 2. 3. 4.
5.
.
Welding in the 3G position qualifies a welder in what positions? 1. 2. 3. 4.
4.
internal discontinuities of a weld surface discontinuities of a weld both internal and surface discontinuities of a weld subsurface discontinuities of a weld
A WPS is a written qualified welding procedure prepared to 1. 2. 3. 4.
.
.
the welder uses SMAW the welder uses GMAW Short Circuiting mode the welder uses GMAW Short Circuiting mode root pass with SMAW fill and reinforcement the welder obtains approval from the inspector
A peripheral seal, on an internal floating roof, shall be designed to accommodate of local deviation between the floating roof and the shell. 1. 2. 3. 4.
the manufacturer's standard + 4 inches + 1/8 inch inspector's experience
ITAC API 653 Practice Exam
Page 3
ITAC 7.
What is the maximum allowable prod spacing using an AC prod technique? 1. 2. 3. 4.
8.
Welders that weld tank shell vertical joints shall be qualified in accordance with 1. 2. 3. 4.
9.
0.020 0.030 0.040 0.050
200oF 93 oC both 1 and 2 50 oF
Each piece of magnetizing equipment shall be calibrated 1. 2. 3. 4.
12.
API 1104 ASME Section V ASME Section IX AWS D1.1
For measuring the thickness of materials using the contact pulse-echo method, temperatures are not to exceed . 1. 2. 3. 4.
11.
.
Geometric unsharpness of the radiograph of a component under 2" thick shall not exceed . 1. 2. 3. 4.
10.
t/2 8 inches 10 inches No spacing required
.
at the beginning of each shift at least once a year or whenever the equipment has been subject to major electrical repair whenever the technician feels like it at least once every 90 days
During calibration of an ammeter the unit shall not deviate by more than scale. 1. 2. 3. 4.
of full
10% 20% 30% 40%
ITAC API 653 Practice Exam
Page 4
ITAC 13.
An inspector is evaluating a radiograph, a bright white image of a "B" appears on a darker background of the radiograph, . 1. 2. 3. 4.
14.
Ultrasonic examination of hot tap connections or reinforcement is required by API 653 when . 1. 2. 3. 4.
15.
the radiograph shall be considered unacceptable the radiograph should not be rejected the "B" is for identification of the welder the "B" is for identification of the weld
in lieu of radiographic testing searching for weld flaws searching for laminations requested by the welder
During an internal inspection of a tank, pitting that measures 0.30 inches deep was found in the shell (0.625 Thickness). The required thickness of the shell in this area is 0.5 inches. Based on the above information should a repair be made? 1. 2. 3. 4.
Yes No The inspector option Repair contractor's option
ITAC API 653 Practice Exam
Page 5
ITAC TThhee ffoolllloow w:: wiinngg aapppplliieess ttoo qquueessttiioonnss 1166 tthhrroouugghh 2255 bbeelloow An inspection is performed on an AST 24' tall, 22' fill height, 94' diameter, water storage service, earth foundation. There is one area of general internal corrosion on the south side of the shell 20" wide and 20" in vertical length. There is evidence of bottom settlement. 16.
Calculate the minimum thickness of the first course based on product alone. 1. 2. 3. 4.
17.
Calculate the minimum thickness for the third course, if each course is 4' in height. 1. 2. 3. 4.
18.
40" 12.68" 6.80" 11.75"
There are three pits aligned vertically on the north side of the tank, in the first course. The diameter of the pits are 1.250", 1", and .500" in length along a vertical line 8" long. Note: Assume pit depth of slightly less than one-half of the minimum acceptable tank shell thickness, exclusive of the corrosion allowance. 1. 2. 3. 4.
20.
.122" .100" .275" .132"
Calculate the "L" length for an area of general corrosion found 10' from the bottom on the south side of the shell, T2 =.125". 1. 2. 3. 4.
19.
1.175" 0.228" 0.551" 0.217"
Because the pits are aligned vertically no repair is required Scattered pits may be ignored If the pit is round, it may be ignored A repair is required
Three circumferentially scattered pits are located on the west side of the tank 18" from the bottom. The pits measure .500", .477" and .732" in diameter. Note: Assume pit depth of one-half of the minimum acceptable tank shell thickness, exclusive of the corrosion allowance. 1. 2. 3. 4.
Because the pits are scattered circumferentially no repair is required All pits may be ignored If the pit is round, it may be ignored A repair is required
ITAC API 653 Practice Exam
Page 6
ITAC 21.
A bulge is found on the tank floor, the diameter of the bulge is 30". What is the maximum permissible height for the bulge? 1. 2. 3. 4.
22.
An area of edge settlement in the tank bottom 6' from the shell has sloped down and settled. The settlement measures 2" at the deepest point. (The bottom lap welds are approximately parallel to the shell). 1. 2. 3. 4.
23.
24 34.2 18.6 Not enough information given
A depression is noted on a section of the bottom near the middle of the east quadrant. The depression measures 5/8" deep, with a diameter of 36 inches. Should a repair be recommended? 1. 2. 3. 4.
25.
A more rigorous stress analysis must be performed The area should be repaired Sloped edge settlement is usually no problem The area should be documented and checked during the next inspection
What is the hydrostatic test height of this tank based on a minimum thickness found in question 16, as the controlling thickness? 1. 2. 3. 4.
24.
11.1" .460" .962" 1.11"
Yes No Not enough information given The tank holds water, no problem
If the maximum liquid level in the tank were to be lowered by 5', what is the minimum thickness of the first course? 1. 2. 3. 4.
1.73" .166" .200" No change from original design thickness
ITAC API 653 Practice Exam
Page 7
ITAC TThhee ffoolllloow w:: wiinngg aapppplliieess ttoo qquueessttiioonnss 2266 tthhrroouugghh 2277 bbeelloow Or RTbc RTip StPr UPr
= = = = =
26.
Using data from above, calculate MRT. (metal loss from the bottom side corrosion). 1. 2. 3. 4.
27.
before
removed ground flush, with grinding direction parallel to the weld ground flush, with grinding direction perpendicular to the weld removed if irregularities mask discontinuities
What is the hydrostatic test height of an in-service welded AST built to API 650, 8th Edition, 82 diameter, 40 tall with a minimum first course thickness of 0.197”. The material of construction is A-516, Grade 70 (A 516M Grade 485). 1. 2. 3. 4.
30.
.250 .070 .002 .080
The weld ripples of reinforcement of butt-welded joints shall be radiography. 1. 2. 3. 4.
29.
.250 .070 .002 .080
Using data from above, calculate MRT. (metal loss from internal corrosion). 1. 2. 3. 4.
28.
10 years .200 .190 .002 .010
40 36 - 2” 32 - 8” 31 - 6”
For a single-wall material thickness, over 0.375" through 0.50", what is the hole-type designation for a source side penetrameter? 1. 2. 3. 4.
15 17 20 25
ITAC API 653 Practice Exam
Page 8
ITAC 31.
The temperature range to conduct a standard technique liquid penetrant examination is . 1. 2. 3. 4.
32.
During an MT examination, 1. 2. 3. 4.
33.
.
5 lbs. 8 lbs. 10 lbs. 40 lbs. .
5 lbs. 8 lbs. 10 lbs. 40 lbs.
A new tank will hold a product with the specific gravity of 1.05; The corrosion allowance is .10; The thickness of the first course is 1.25 inches; Hydrostatic test stress 25,000 PSI. What is the thickness required for the annular plate? (Note: Include corrosion allowance). 1. 2. 3. 4.
36.
100% coverage at the required sensitivity a calibration of each piece of magnetizing equipment at least three separate examinations prod spacing of at least 10"
A DC yoke shall have a lifting power of at least 1. 2. 3. 4.
35.
shall be performed on each area.
An AC yoke shall have a lifting power of at least 1. 2. 3. 4.
34.
50oF to 135oF 50oF to 125oF 70oF to 115oF 50oF to 80oF
5/16" 11/16" 3/8" 7/16"
A leak is noted 1 1/2” away from the shell-to-bottom weld in the floor of an existing welded tank. The hole in the floor is 4” in diameter. What type of repair, in compliance with API 653, 3rd Edition, should be made? 1. 2. 3. 4.
Use RBI. Because the product might not contaminate the soil or waterways, no repair is required. Weld build-up the area. Install a tombstone shaped, welded-on patch plate, intersecting the shell-to-bottom joint at approximately 90o. Install a non-welded patch plate and fiberglass/epoxy to coat the area.
ITAC API 653 Practice Exam Page 9
ITAC 37.
When using the SMAW process, a welder has changed from an F number 4 electrode to an F number 3 electrode. Does the procedure need to be requalified? 1. 2. 3. 4.
38.
During a welder qualification test, for plate coupons, all surfaces (except areas designated "discard") shall . 1. 2. 3. 4.
39.
1/4" 3/16" 1/8" 1/16"
If piping near the tank enters the ground, the soil should be excavated inspection. 1. 2. 3. 4.
42.
0.655 0.611 0.563 0.500
In order to comply with API 650, the finished surface of a weld reinforcement on plate 1/2" thick, horizontal butt joints, may have a reasonably uniform crown not to exceed , for radiographic examination. 1. 2. 3. 4.
41.
show complete joint penetration with complete fusion of weld metal and base metal show no more than 1/3t inadequate penetration show no more than 1/3t nonfusion be allowed one 5/32" crater crack
What is the hydrostatic test thickness for a new tank whose diameter is 150, and has a fill height of 40? The shell material is A 36M. 1. 2. 3. 4.
40.
Yes No Only if low hydrogen electrodes are used API 650 allows this change
inches for
1–3 3–6 6 – 12 Piping is not addressed by any of the documents listed in the API 653 Body of Knowledge.
Floating roofs on new tanks shall be sufficiently buoyant to remain floating after 1. 2. 3. 4.
.
Fifteen inches of rainfall in a 24-hour period Ten inches of rainfall in a 24-hour period Thirty inches of snow in a 24-hour period Thirty inches of sand in a 24-hour period
ITAC API 653 Practice Exam
Page 10
ITAC 43.
A sudden rapid fracture under stress, where the material exhibits little or no evidence of ductility or plastic deformation, is called .? 1. 2. 3. 4.
44.
Each floor scanning operator, who only use the bottom scanning equipment, shall receive a minimum of hours of training. 1. 2. 3. 4.
45.
brittle fracture cavitation atmospheric corrosion caustic corrosion
8 12 20 40
Variables in the procedure that can be changed without having to re-qualify the procedure and/or the scanning operators are . 1. 2. 3. 4.
essential variables non-essential variables qualification tests TBEQ
Q whhiicchh Prroocceedduurree w RP QR PQ S//P PS WP Quueessttiioonnss 4466 tthhrroouugghh 5500 aappppllyy ttoo tthhee W bbeeggiinnss oonn ppaaggee 1122.. 46.
What is the root face limitation as listed on the attached WPS and PQR? 1. 2. 3. 4.
47.
If the supporting PQR is used, are the P-nos correct on the attached WPS? 1. 2. 3. 4.
48.
3/32” 1/8” No limit Not designated
Yes No Could be if properly preheated Not enough information
Is the thickness range on the WPS supported by the PQR? 1. 2. 3. 4.
Yes No Requalification is required by API 570 Requalification is required by ASME V
ITAC API 653 Practice Exam
Page 11
ITAC 49.
Is the attached PQR properly qualified? 1. 2. 3. 4.
50.
No, because RT is not allowed during PQR qualification No, because there are not enough tensile tests No, because peening is allowed by B31.3 Yes
What should have been the correct number and type of guided bends on the PQR? 1. 2. 3. 4.
6 side bends 2 face and 2 root bends 1 side, 1 face and 1 root bend 2 face, 2 root and 4 side bends
ITAC API 653 Practice Exam
Page 12
QW-482 SUGGESTED FORMAT FOR WELDING PROCEDURE SPECIFICATIONS (WPS) (See QW-200.1, Section IX, ASME Boiler and Pressure Vessel Code) Company Name: DLV WELDING, INC. By: I.A. WELDER Welding Procedure Specification No. S M A W - P 1 Date: 1 1 / 2 2 / 0 1 Supporting PQR No.(s) SMAW-P1-A Revision No. Date: Welding Process(es): SMAW Type(s): MANUAL Automatic, Manual, Machine, or Semi-Auto
JOINTS (QW-402) Joint Design SINGLE VEE, ALL FILLETS Backing (Yes) (No) X Backing Material (Type) N/A
Details
(Refer to both backing and retainers) Metal Nonmetallic
Nonfusing Metal Other
Sketches, Production Drawings, Weld Symbols or Written Description should show the general arrangement of the parts to be welded. Where applicable, the root spacing and the details of weld groove may be specified.
3/32” – 1/8”
(At the option of the Mfgr., sketches may be attached to illustrate joint design, weld layers and bead sequence, e.g., for notch toughness procedures, for multiple process procedures, etc.)
*BASE METALS (QW-403) P-No. 1 Group No. 1 to P-No. 8 OR Specification type and grade to Specification type and grade OR Chem. Analysis and Mech. Prop. to Chem. Analysis and Mech. Prop. Thickness Range: Base Metal: Groove .125 – 1” U Pipe Dia. Range: Groove UNLIMITED Other: N No pass greater than 1/2”
E
Group No.
2 E1 S 1 8
A
1
Fillet Fillet
*FILLER METALS (QW-404) SMAW Spec. No. (SFA) 5.1 AWS No. (Class) E-6010 F-No. 2 A-No. 1 Size of Filler Metals 3/32” – 1/8” Weld Metal Thickness Range: Groove .250” max. Fillet ALL Electrode-Flux (Class) N/A Flux Trade Name N/A Consumable Insert N/A Other SUPPLEMENTAL FILLER SHALL NOT BE USED
2
ALL ALL SMAW 5.1 E-7018 2 1 3/32” – 1/8” .750” max ALL N/A N/A N/A
*Each base metal-filler metal combination should be recorded individually
ITAC API 653 Practice Exam
Page 13
QW-482 (Back) WPS No. SMAW-P1
POSITIONS (QW-405)
Rev.
POSTWELD HEAT TREATMENT (QW-407)
Position(s) of Groove FLAT Welding Progression: Up N / A Position(s) of Fillet
Temperature Range Time Range
Down N / A
NONE
GAS (QW-408) PREHEAT (QW-406)
Percent Composition Gas(es) (Mixture) Flow Rate 5 0o F
Preheat Temp. - Min. Interpass Temp. - Max. Preheat Maintenance
Shielding Trailing Backing
(Continuous or special heating where applicable should be recorded)
N/A N/A N/A
______ ______ ______
______ ______ ______
ELECTRICAL CHARACTERISTICS (QW-409) Current AC or DC Amps (Range)
DC 70-160
Polarity
DCRP
Volts (Range)
19-30
(Amps and volts range should be recorded for each position, and thickness, etc. This information may be listed in a tabular form similar to that shown below. Tungsten Electrode Size and Type
N/A
Mode of Metal Transfer for GMAW
N/A
(Pure Tungsten, 2% Thorated, etc.) (Spray arc, short-circuiting arc, etc.) Electrode Wire feed speed range
TECHNIQUE (QW-410) String or Weave Bead STRING OR WEAVE Orifice or Gas Cup Size N/A Initial and Interpass Cleaning (Brushing, Grinding, etc.) HAND AND POWER TOOLS MAY BE USED Method of Back Gouging Oscillation Contact Tube to Work Distance Multiple or Single Pass (per side) Multiple or Single Electrodes Travel Speed (Range) Peening Other
N/A N/A N/A E-6010 SINGLE SINGLE NONE
Filler Metal Weld Layer(s) 1
Process
Class
SMAW
E-6010
3/32 1/8”
E-7018
3/32 1/8”
BALANCE SMAW
E-7018 MULTIPLE
Dia.
Current Type Polar DCEP
DCEP
Amp Range 70-130
70-160
Volt Range
Travel Speed Range
Other (e.g., Remarks, Comments, Hot Wire Addition, Technique, Torch Angle, Etc.)
24-30 1 1/2 51PM 19-28 2-81PM
ITAC API 653 Practice Exam
Page 14
QW-483 SUGGESTED FORMAT FOR PROCEDURE QUALIFICATION RECORD (PQR) (See QW-200.2, Section IX, ASME Boiler and Pressure Vessel Code) Record Actual Conditions Used to Weld Test Coupon Company Name DLV WELDING, INC. Procedure Qualification Record No. SMAW P1-A WPS No. SMAW – P1 Welding Process(es) SMAW Types (Manual, Automatic, Semi-Auto.) MANUAL
Date 1 1 / 2 2 / 0 1
JOINTS (QW-402)
3/32” – 1/8”
Groove Design of Test Coupon (For combination qualifications, the deposited weld metal thickness will be required for each filler metal or process used.)
BASE METALS (QW-403) Material Spec. A-283 Type or Grade C P. No. 1 to P-No. Thickness of Test Coupon .500 Diameter of Test Coupon N/A Other
POST WELD HEAT TREATMENT (QW-407) Temperature Time Other
1
NONE N/A
GAS(QW-408)
FILLER METALS (QW-404) SFA Specification 5.1 AWS Classification E-6010 Filler Metal F-No. 2 Weld Meal Analysis A-No. 1 Size of Filler Metal 1/8” Other Weld Metal Thickness
.250 max
7018 5.1 E-7018 2 1 3/32”
.500 max
Shielding Trailing Backing
Gas(es) N/A N/A N/A
Percent Composition (Mixture) Flow Rate _______ ________ _______ ________ _______ ________
ELECTRICAL CHARACTERISTICS (QW-409) Current DC Polarity DCEP Amps. 7 0 - 1 6 0 Volts Tungsten Electrode Size N/A Other
19 - 30
POSITION (QW-405)
TECHNIQUE (QW-410)
Position of Groove 3G Weld Progression (Uphill, Downhill) Other
Travel Speed 1 1/2 – 8 IPM String or Weave Bead BOTH Oscillation N/A Multipass or Single Pass (per side) BOTH Single or Multiple Electrodes S I N G L E Other
PREHEAT (QW-406) Preheat Temp. Interpass Temp. Other
UPHILL
5 0oF
ITAC API 653 Practice Exam
Page 15
QW-483 (Back) PQR No.
SMAW-P1-A
Tensile Test (QW-150) Specimen No.
Width
1
1.5
Thickness
.5
Area
.75
Ultimate Total Load lb.
97,900
Ultimate Unit Stress psi
Type of Failure & Location
77,484
BASE
Guided-Bend Tests (QW-160) Type and Figure No.
1 2 3 4
SIDE BEND SIDE BEND FACE BEND ROOT BEND
GOOD GOOD GOOD GOOD
POROSITY 1/16” DIA.
Toughness Tests (QW-170) Specimen No.
Notch Location
Notch Type
Test Temp.
Impact Values
Lateral Exp. % Shear Mils
Drop Weight Break No Break
Fillet-Weld Test (QW-180) Result- Satisfactory: Macro - Results
Yes
No
Penetration into Parent Metal: Yes
No
Other Tests Type of Test RT - GOOD Deposit Analysis Other ...................................................................................................................................................... Welders Name TOM SMITH Clock No. Tests conducted by: O,K. TEST LAB
BR549 Stamp No. Laboratory Test No.
JP 11-22-01-637
We certify that the statements in this record are correct and that the test welds were prepared, welded, and tested in accordance with the requirements of Section IX of the ASME Code. Manufacturer Date
11-22-04
By
DLV WELDING, INC. (SIGNED)
(Detail of record of tests are illustrative only and may be modified to conform to the type and number of test required by the Code.)
1/06 Practice Exam
Page 16
Please close all materials. The remainder of the exam is “Closed Book.”
1/06 Practice Exam
Page 17
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1/06 Practice Exam
Page 18
Visit our website www.itac.net
TThhee sseeccoonndd ppaarrtt ooff tthhee eexxaam Booookk,,"" m iiss ""C Clloosseedd B 51.
Who has the ultimate responsibility for complying with the provisions of API Standard 653? 1. 2. 3. 4.
52.
If cracks are suspected in nozzles or nozzle welds they should be checked by . 1. 2. 3. 4.
53.
?
erosion brittle fracture caustic corrosion phase failure
Per API 653, tanks shall have a formal visual inspection once every or RCA/4N years, whichever is less. 1. 2. 3. 4.
55.
ultrasonic digital thickness gauge MT or PT examination eddy current testing infra-red thermography
Localized corrosion due to the concentration of caustic or alkaline salts is 1. 2. 3. 4.
54.
API Owner/operator Inspector Contractor/builder
years
three four five seven
Monthly visual inspections of the external condition of in-service tanks may be performed by . 1. 2. 3. 4.
API 653 inspectors owner/operator personnel NDE technicians plant managers
1/06 Practice Exam
Page 19
ITAC 56.
The critical zone for repairs to tank bottoms is that portion of the bottom or annular plate within inches of the inside edge of the shell. 1. 2. 3. 4.
57.
On a fixed-type roof, planks long enough to span at least laid and used as walkways. 1. 2. 3. 4.
58.
Every 10 years Every time the tank is empty Annually Semi-annually .
arc blow arc length arc strike arc angle
During the reconstruction of a tank shell, welding operators, welders and welding procedures must be qualified in accordance with . 1. 2. 3. 4.
61.
none allowed 1 2 3
The deflection of an arc from its normal path because of magnetic forces is 1. 2. 3. 4.
60.
roof rafters should be
Cathodic protection surveys are recommended to ensure the effectiveness of cathodic protection. How often should this survey be done? 1. 2. 3. 4.
59.
3 6 12 24
API 650 ASME Section V ASME Section IX API 1104
Upon completion, the roof of a tank designed to be gas tight shall be tested by which one of the following methods? 1. 2. 3. 4.
Magnetic particle testing of all welds Application of internal air pressure not exceeding the weight of the roof plates and applying a solution suitable for the detection of leaks Penetrant testing the weld joints Visual inspection of the weld joints
1/06 Practice Exam
Page 20
ITAC 62.
In regard to API 653, roof plates corroded to an average thickness of any 100 square inch area shall be repaired or replaced. 1. 2. 3. 4.
63.
64.
erection/fabrication manufacturer purchaser Nuclear Regulatory Commission certified inspector .
round discontinuity linear discontinuity non-linear discontinuity rejectable defect
brittle fracture caustic corrosion stress cracking atmospheric corrosion
Which of the following tanks are used to reduce filling and breathing loss by eliminating vapor space? 1. 2. 3. 4.
68.
.
A form of corrosion that occurs from moisture associated with atmospheric conditions is called . 1. 2. 3. 4.
67.
brazing SMAW weld autogenous weld SAW weld
A discontinuity with a length that is substantially greater than its width is called a 1. 2. 3. 4.
66.
.
Each welder making welds on a tank shall be certified by 1. 2. 3. 4.
65.
less than 0.09 0.09 greater than 0.09 no API 653 requirement, owner's requirement
A fusion weld made without filler metal is 1. 2. 3. 4.
inch in
Cone roof tank Umbrella-roof tank Vapor-dome roof tank Floating roof tank
Per API 650, external floating roof deck plates having support leg or other rigid penetrations closer than inches to lap weld seams must be full fillet welded not less than 2 inches on 10 inch centers. 1. 2. 3. 4.
6 12 14 18 1/06 Practice Exam
Page 21
ITAC 69.
Foundation pads that have washed out or settled under the bottoms of atmospheric storage tanks can be repaired by . 1. 2. 3. 4.
70.
When corrosion rates are not known and similar service experience is not available, the actual bottom thickness shall be determined by inspections within the next year(s) of tank operation to establish corrosion rates. 1. 2. 3. 4.
71.
chemical attack sulfate - type alkalis chlorides high temperature
10 5 20 15
Upon completion of welding of the new tank bottom, the welds shall be inspected by which one of the following methods? 1. 2. 3. 4.
75.
.
A contributing factor for determining internal inspection intervals shall be time, not to exceed years for any reason, if an RBI program is not in place. 1. 2. 3. 4.
74.
.
inclusion corrosion fatigue peening
Calcining can occur when concrete has been exposed to 1. 2. 3. 4.
73.
five ten three one
The mechanical working of metals using impact blows is referred to as 1. 2. 3. 4.
72.
pumping in water pumping in argon pumping in sand, dirt or thin concrete pumping in gas
Radiographs Vacuum Penetrant testing Hammer testing
The junction of the weld face and the base metal is the 1. 2. 3. 4.
?
heat affect zone weld toe stress riser dilution zone 1/06 Practice Exam
Page 22
ITAC 76.
Tank plates being welded which do not have proper identification shall be subjected to . 1. 2. 3. 4.
77.
An assembly whose component parts are joined by welding is a 1. 2. 3. 4.
78.
Repair Alteration Hot tap Reconstruction
10 30 24 18
For known materials, all shell plates and bottom plates welded to the shell shall meet, as a minimum, the chemistry and mechanical properties of material specified for the application with regard to thickness and design metal temperature, per . 1. 2. 3. 4.
81.
spool piece weldment fillet weld groove weld
Annular bottom plates shall have a radial width that provides at least inches between the inside of the shell and any lap-welded joint in the remainder of the bottom. 1. 2. 3. 4.
80.
.
identifies a procedure for installing a nozzle in the shell of a tank that is in service. 1. 2. 3. 4.
79.
chemical analysis UT thickness measurements PT testing RT testing
ASM Requirements ASME Requirements API 650 Requirements ASTMA 7 Requirements
What action should be taken after a flat spot is discovered in the second ring of a 200' diameter AST? 1. 2. 3. 4.
The shell distortion shall be evaluated The area shall be cut out and replaced Since no product is leaking out of the area, it may be ignored The inspector has the option to repair or ignore
1/06 Practice Exam
Page 23
ITAC 82.
Routine in-service visual inspections of the external condition of the tank shall not exceed . 1. 2. 3. 4.
83.
A separation at the joint root between the work pieces is referred to as a 1. 2. 3. 4.
84.
.10 .075 .15 .05
one month one year five years, (unknown corrosion rate) ten years, (unknown corrosion rate)
Cavity-type discontinuities formed by gas entrapment during solidification of the weld are . 1. 2. 3. 4.
87.
gap root face root edge root opening
When used, the ultrasonic thickness measurements shall be made at intervals not to exceed . 1. 2. 3. 4.
86.
.
Minimum thickness for tank bottom plate, when there is no means of leak detection and containment, is inch. 1. 2. 3. 4.
85.
one month six months one year five years
cracks tungsten inclusion slag porosity
The most likely point of occurrence of cracks in riveted tanks is around 1. 2. 3. 4.
.
internal piping flanged connections roof seals rivet holes
1/06 Practice Exam
Page 24
ITAC 88.
Qualified inspectors shall have education and experience equal to at least one of the following: 1. 2. 3. 4.
89.
The maximum acceptable undercutting of the base metal for vertical butt joints is inch. 1. 2. 3. 4.
90.
.
full fillet welded with complete fusion butt-welded with complete penetration and complete fusion lap-welded with complete penetration and complete fusion single grove with backing strip
A non-metallic product resulting from the mutual dissolution of flux and non-metallic impurities in some welding processes is . 1. 2. 3. 4.
93.
year
5 7 10 15
On a reconstructed tank, all new shell joints shall be 1. 2. 3. 4.
92.
3/32 1/8 1/64 3/64
When used, ultrasonic thickness measurements shall be made at intervals after commissioning new tanks. 1. 2. 3. 4.
91.
a degree in engineering plus 1 year of experience in inspection of tanks, pressure vessels or piping two years of experience in work related field two year certificate in technology from technical college high school education
porosity tungsten inclusion slag cracking
A double-welded butt weld is 1. 2. 3. 4.
.
a joint between two abutting parts lying in approximately the same plane a joint between two abutting parts lying in approximately the same plane that is welded from both sides a joint between two overlapping members in which the overlapping edges of both members are welded with fillet welds a fillet weld whose size is equal to the thickness of the thinner joined member
1/06 Practice Exam
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ITAC 94.
All requirements of API 650, , shall be considered before changing the o service of a tank to operation at temperatures above 200 F. 1. 2. 3. 4.
95.
API 650 ASME Article 4 AWS D1.1 API 1104
20 70 90 150
A fracture-type discontinuity characterized by a sharp tip and high ratio of length to width to opening displacement is referred to as . 1. 2. 3. 4.
99.
.
Qualification test plates for floor scan, with flaws, should be a minimum of sq. ft. 1. 2. 3. 4.
98.
inch flanged or
one two three four
The API 653 standard employs the principles of 1. 2. 3. 4.
97.
M J C K
Openings in tank shells larger than required to accommodate a threaded nozzle shall be reinforced. 1. 2. 3. 4.
96.
Appendix Appendix Appendix Appendix
crack slag porosity spatter
The acceptability of welds examined by radiography shall be judged by the standards in . 1. 2. 3. 4.
ASME Section V, Division 7 ASME Section IX, Paragraph QW191 ASME Section VIII, Division 1, Paragraph UW-51(b) API 1104
1/06 Practice Exam
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ITAC 100.
Per API 653, what is the maximum allowable banding, using a vertical 36" sweep board? 1. 2. 3. 4.
101.
The arrangement of direct current arc welding leads in which the electrode is the negative pole and the work piece is the positive pole of the welding arc is ? 1. 2. 3. 4.
102.
10 30 50 100
What is the maximum allowable misalignment on a 3/4" vertical butt joint? 1. 2. 3. 4.
105.
reconstruction rebuilding reworking alteration
When bottom annular plates are required by paragraph 3.5.1 of API 650, the radial joints shall be radiographed. For single welded joints using a backup bar, one spot radiograph shall be taken on percent of the radial joints. 1. 2. 3. 4.
104.
DCEN DCEP AC AC/DC
Any work on a tank that changes its physical dimensions or configuration is considered a/an . 1. 2. 3. 4.
103.
1" 1/2" 3/8" 3/32"
10% 1/16" 10% or maximum of 1/8" 12% or maximum of 3/32"
Atmospheric storage tanks are those tanks that have been designed to operate in their gas and vapor spaces at internal pressures which approximate pressure. 1. 2. 3. 4.
16 lbs. to 25 lbs. 12 lbs. to 15 lbs. more than 25 lbs. atmospheric
1/06 Practice Exam
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ITAC 106.
The arrangement of direct current welding leads in which the electrode is the positive pole and the work piece is the negative pole of the welding arc is ? 1. 2. 3. 4.
107.
The portion of the groove face within the joint root is called 1. 2. 3. 4.
108.
be hand or machine stamped be stamped every 3 feet be stamped on the top side of each nozzle an in every 3 feet of roof weld not require identification inches outside the tank
1 1/2 2 3 4
100% RT Spot RT MT Visual
NDE examiners that meet the requirements of ASME Section V, Article 1, are qualified with ASNI/ASNT CP-189 or . 1. 2. 3. 4.
112.
:
For penetrations using insert plates, how shall the completed butt welds between the insert plate and shell plate be inspected? 1. 2. 3. 4.
111.
land root face stringer bead root pass
Annular bottom plates must extend a minimum of shell. 1. 2. 3. 4.
110.
.
Welder identification on roof welds and flange-to-nozzle neck welds shall 1. 2. 3. 4.
109.
DCEN DCEP AC AC/DC
AWS QC-1 API ASNT SNT-TC1A ABS
The maximum operating temperature for tanks constructed to API 650 (not including appendices) is . 1. 2. 3. 4.
500° F 500° C 200° F 200° C 1/06 Practice Exam
Page 28
ITAC 113.
New for floating roof support legs and for fixed roof support columns shall be installed when replacing a tank floor. 1. 2. 3. 4.
114.
Where does the new nameplate need to be attached to a reconstructed tank? 1. 2. 3. 4.
115.
original shell thickness measurements taken within 180 days prior to relocation measurements taken when the tank was removed from service new product loads
amount of product needed the specific gravity of the product material coating number of penetrations in the first shell course
SW is the acronym for what type of welding? 1. 2. 3. 4.
119.
.
The maximum design liquid level for product shall be determined by calculating the maximum design liquid level for each shell course based on . 1. 2. 3. 4.
118.
17 years 15 years 20 years 10 years
The design thickness of a reconstructed tank is based on 1. 2. 3. 4.
117.
Adjacent to the existing nameplate Does not need one On the roof Over the suction piping
The corrosion rate for an AST is 5 mils per year. Based on API 653 requirements when should the next external UT inspection be scheduled? Note: Remaining Corrosion Allowance is .17 inches. 1. 2. 3. 4.
116.
mud rings leg guides bearing plates support leg pins
Submerged Welding Shielded Metal Arc Welding Slick Welding Stud Welding
You are adding a 6 inch blending nozzle to the bottom course, the shell is 5/8" thick. What size insert plate is required when used with a reinforcement plate? 1. 2. 3. 4.
12" diameter 18" diameter Three times the diameter of the penetration The diameter of the reinforcement plate, plus 12" 1/06 Practice Exam
Page 29
ITAC 120.
Who is responsible for compliance with the API 650 standards? 1. 2. 3. 4.
121.
settlement occurs when the tank shell settles sharply around the periphery, resulting in deformation of the bottom plate. 1. 2. 3. 4.
122.
Uniform settlement Rigid body Out-of-Plane settlement Differential settlement
GMAW GMAW GMAW GMAW
- Pulsed - Spray - G - S
The minimum thickness of new roof plates shall be allowances, as specified in the repair specifications. 1. 2. 3. 4.
126.
after replacement of door sheet that intersects the shell-to-bottom weld when a 36-inch nozzle has been installed after partial or complete jacking of a tank shell if the owner or operator has authorized the exemption in writing
Due to the fast-freezing nature of this process, there is potential for lack of sidewall fusion when welding thick-wall equipment or a nozzle attachment. 1. 2. 3. 4.
125.
.
Which type of tank settlement will rotate the tank in a tilted plane? 1. 2. 3. 4.
124.
Uniform Edge Out-of-Plane Rigid Body Tilting
A full hydrostatic test can be waived on a tank 1. 2. 3. 4.
123.
Manufacturer Purchaser State Inspector API 653 Inspector
1/2 7/8 3/16 3/8
Express 50 mils as 1. 2. 3. 4.
inch, plus any corrosion
inch(es).
.500 .050 .005 .0005 1/06 Practice Exam
Page 30
ITAC 127.
For replacement of tank bottom floor, what is a suitable non-corrosive material for use between the old and new floor? 1. 2. 3. 4.
128.
According to API 653, the basis for repairs and alterations shall be an 1. 2. 3. 4.
129.
One radiograph shall be taken in every vertical joint 100% of the vertical joint Two radiographs shall be taken in the vertical joint No radiographs required .
frequent freezing and thawing of the ground nearby equipment operating with extreme vibration too much product being stored in the tank high wind
Storage tanks shall be 1. 2. 3. 4.
133.
butt welded lap welded riveted chemically bonded
Settlement can result from 1. 2. 3. 4.
132.
joints, with complete penetration.
During the repair of an AST, one new vertical shell weld was installed. How many radiographs are required on the vert? (The shell is 1.25" thick). 1. 2. 3. 4.
131.
.
API Standard 650 equivalence API Standard 2207 equivalence ASME Section V equivalence AWS D 1.1 equivalence
All new shell joints shall be 1. 2. 3. 4.
130.
Dirt Sand or concrete Fiberglass insulation Air
and gas-freed prior to commencement of dismantling.
filled drained cleaned vented
All bottom plates shall have a minimum nominal thickness of inch, exclusive of any corrosion allowance specified by the purchaser for the bottom plates. 1. 2. 3. 4.
3/8 .250 .516 .325 1/06 Practice Exam
Page 31
ITAC 134.
means the work necessary to reassemble a tank that has been dismantled and relocated to a new site. 1. 2. 3. 4.
135.
Repairs shall not be attempted on a tank that is filled with or on a tank that has contained until the tank has been emptied, cleaned and gas freed in a safe manner. 1. 2. 3. 4.
136.
diesel air stress gas
Ultrasonic acceptance standards, in accordance with API 653, shall be 1. 2. 3. 4.
140.
25% with a maximum of 1/16" 2% with a maximum of 3/64" 5% with a maximum of 3/8" 10% with a maximum of 1/8"
New or altered reinforcing plates of shell penetrations shall be given a(n) test, in accordance with API Standard 650. 1. 2. 3. 4.
139.
a new tank an in-service tank a reconstructed tank an out-of-service tank
Misalignment in completed vertical joints over 5/8" shall not exceed what percentage of the plate thickness? 1. 2. 3. 4.
138.
nitrogen oil water grain
According to API 653, a full hydrostatic test, held for 24 hours, shall be performed on: 1. 2. 3. 4.
137.
Reconstruction Rebuilding Reworking Alteration
.
ASME Section VIII ASME Section V ASME Section XI Agreed upon by the purchaser and the manufacturer
Column-based clip-guides shall be welded to the tank bottom to prevent 1. 2. 3. 4.
.
internal erosion structural uplifting lateral movement of column bases lateral expansion and contraction 1/06 Practice Exam
Page 32
ITAC 141.
Any specific design considerations, other than normal product loading, shall be specified by . 1. 2. 3. 4.
142.
A(n) occurs. 1. 2. 3. 4.
143.
A(n) occurs. 1. 2. 3. 4.
144.
bathode anode cathode electrolyte is an electrode of an electrochemical cell at which a reduction reaction bathode anode cathode electrolyte
vacation surface interruption stress riser holiday
occurs when two metals with different compositions (thus different electrolytic potentials) are connected in an electrolyte (usually soil). 1. 2. 3. 4.
146.
is an electrode of an electrochemical cell at which oxidation (corrosion)
A is a discontinuity in a coating film that exposes the metal surface to the environment. 1. 2. 3. 4.
145.
owner/operator contractor engineer welding foreman
Scattered metal growth Scattered metal blistering Galvanic corrosion Erosion
A Galvanic system is a 1. 2. 3. 4.
.
system that uses a metal less active than the structure to stop corrosion system that uses a metal more active than the structure to stop corrosion system that uses a chemical to stop corrosion system that uses a coating to stop corrosion
1/06 Practice Exam
Page 33
ITAC 147.
All tanks shall be given a formal visual external inspection by an inspector qualified in accordance with API 653, Paragraph 4.10 at least every years. 1. 2. 3. 4.
148.
Welding consumables shall conform to the the intended use. 1. 2. 3. 4.
149.
classification that is applicable to
ASNT AWS ASME API
The rules given in API 653 are reconstruction. 1. 2. 3. 4.
150.
10 7 6 5
for tank inspection, repairs, alterations and
minimum requirements maximum requirements guideline requirements suggested requirements
means any work on a tank involving cutting, burning, welding or heating operations that changes the physical dimensions and/or configuration of a tank. 1. 2. 3. 4.
Repair Reconstruction Reworking Alteration
1/06 Practice Exam
Page 34
nspection raining nd onsulting Post Office Box 5666 Pasadena, TX 77508-5666 Phone (281) 998-8305 Fax (281) 998-2163
Visit our website "www.itac.net".
1. 2. 3. 4. 5. 6. 7. 8.
2 1 3 3 1 2 2 3
(Page 95, Par. T-620) ASME V (Page 13, Par. QW-200.1a) ASME IX (Page 150, Par. QW-461.9) ASME IX (Page 22, Par. QW-252) ASME IX (Page 53, Par. QW-304) ASME IX (Page H-4, Par. H.4.4.3) API 650 (Page 107, Par. T-752.3) ASME V (Page 11-1, Par. 11.1.1) API 653 (Page 7-2, Par. 7.3.2) API 650 9. 1 (Page 10, Par. T-274.2) ASME V 10. 3 (Page 388, Par. 1.1) ASME V 11. 2 (Page 109, Par. T-761(a) ASME V 12. 1 (Page 109, Par. T-761(c) ASME V 13. 1 (Page 15, Par. T-284) ASME V 14. 3 (Page 12-1, Par. 12.1.2.1) API 653 15. 2 (Page 4-3, Par. 4.3.2.2) API 653 16. 4 (Page 4-3, Par. 4.3.3.1) API 653 Solution: Use the formula, Minimum Thickness Calculation for Welded Tank Shell: tmin= 2.6 (H-1)DG SE tmin=
2.6 (22-1) (94)(1) 23,600
tmin=
5,132.4 23,600
tmin=
.217"
Values substituted
17. 1 (Page 4-3, Par. 4.3.3.1) API 653 Solution: Use the formula, Minimum Thickness Calculation for Welded Tank Shell. tmin= 2.6 (H-1)DG SE tmin=
2.6 (14-1) (94)(1) 26,000(1)
tmin=
3,177.2 26,000
tmin=
.122
Values substituted
18. 2 (Page 4-2, Par. 4.3.2) API 653 Solution: Use the formula, Actual Thickness Determination. L = 3.7 √ (Dt2) L = 3.7 √ (94) (.125)
Values substituted
L = 3.7 √ (11.75) L = 3.7 X 3.428 L = 12.68" 19. 4 (Page 4-3, Par. 4.3.2.2b) API 653 Solution: Use the Pit Measurement Technique. d1 + d2 + d3 ... < 2" 1.250 + 1 + .500 = 2.750"
Values substituted
20. 1 (Page 4-3, Par. 4.3.2.2a) API 653 21. 2 (Page B-7, Par. B.3.3) API 653 22. 4 (Page B-9, Fig. B-10) API 653 23. 1 (Page 4-5, Par. 4.3.3.2) API 653 Solution: Use the formula, Hydrostatic test height for welded tank shells. Ht = StE tmin +1 2.6D+1 St = 26,000 (From Table 4-1) Ht = (26,000) (1) (.218) +1 2.6(94) Ht = 5668 244.4
+1
Ht = 23.19 + 1 Ht = 24.19 (Rounded to 24)
Revised 01/07
24. 1 (Page B-7, Par. B.3.3) API 653 Solution: Use the formula: BB = 0.37R BB = 0.37 (1.5) Values substituted BB =
29. 4 (Page 4-5, Par. 4.3.3.2) API 653 Solution: Use the formula, Hydrostatic test height for welded tank shells. Ht = StE tmin +1 2.6D St = 33,000 (From Table 4-1)
.555" (Fig. B-9, same answer)
Ht = (33,000) (1) (.197) 2.6(82)
25. 2 (Page 4-3, Par. 4.3.3.1) API 653 Solution: Use the formula, Minimum Thickness Calculation for Welded Tank Shell. tmin=
tmin=
tmin=
tmin=
Ht = 6501 213.2
2.6 (H-1)DG SE 2.6 (17-1) (94)(1) 23,600(1)
Ht = 31.49’ or (approx. 31’ 6")
Values substituted
3,910.4 23,600 .166"
30. 31. 32. 33. 34. 35. 36. 37. 38. 39.
2 2 1 3 4 3 3 1 1 2
MRT = RTbc - Or(StPr + UPr)
(Pg 109, Par T-762(b)) ASME Sec V, Art 7 (Pg 109, Par T-762(c)) ASME Sec V, Art 7
(Page 3-6, Par. 3.5.3) API 650 (Page 9-7, Par. 9.10.1.2 (b)) API 653 (Pg 22, Par. QW-253) ASME Sec IX (Pg 9, Par. QW-194) ASME Sec IX (Page 3-7, Par. 3.6.3) API 650
Tt = 2.6 X 150 (40-1) 24,900
27. 2 (Page 4-9, Par. 4.4.7.1) API 653 Solution: Use the formula, Minimum Thickness for Tank Bottom Plate.
Tt = 390 (39) 24,900
MRT = RTip - Or(StPr + UPr)
Tt = 15,210 24,900
MRT = .190 - 10(.002 + .010) Values substituted MRT = .190 - 10(.012) MRT = .190 - .12 MRT = .070 (Pg 7, Par T-222.2) ASME Sec V
(Pg 13, Tbl T-276)) ASME Sec V, Art 2 (Pg 96, Par T-652) ASME Sec V, Art 6 (Pg 112, Par T-774) ASME Sec V, Art 7
Tt = 2.6D(H-1) St
MRT = .200 - 10(.002 + .010) Values substituted MRT = .200 - 10(.012) MRT = .200 - .12 MRT = .080
4
+1
Ht = 30.49' +1
26. 4 (Page 4-9, Par. 4.4.7.1) API 653 Solution: Use the formula, Minimum Thickness for Tank Bottom Plate.
28.
+1
Tt = 0.611 (round to .625 plate) 40. 41. 42. 43.
4 3 2 1
(Page 6-3, Par. 6.1.3.4) API 650 (Page 35, Par. 7.2.10) API 575 (Page C-1, Par. C.3.4.1) API 650 (Page 4-19, Par. 4.2.7.1) API 571 Revised 01/07
44. 45. 46. 47. 48. 49. 50. 51. 52. 53. 54. 55. 56. 57. 58. 59. 60. 61. 62. 63. 64. 65. 66. 67. 68. 69. 70. 71. 72. 73. 74. 75. 76. 77. 78. 79. 80. 81. 82. 83. 84. 85. 86. 87. 88. 89. 90. 91. 92. 93. 94.
4 2 4 2 2 2 2 2 2 3 3 2 1 3 3 1 3 2 1 3 1 2 4 4 2 3 2 4 4 3 2 2 1 2 3 3 3 1 1 4 1 3 4 4 1 3 1 2 3 2 1
(Page G-2, Par. G.4.4) API 653 (Page G-1, Par. G.2.5) API 653 (PQR and WPS (PQR and WPS) (QW-451.1, Pg. 138) ASME Sec. IX (QW-451.1, Pg. 138) ASME Sec. IX (QW-451.1, Pg. 138) ASME Sec. IX (Page 1-1, Par. 1.2) API 653 (Page 17, Par. 5.4) API 575 (Page 4-95, Par. 4.3.10.1) API 571 (Page 6-1, Par. 6.3.2.1) API 653 (Page 6-1, Par. 6.3.1.1) API 653 (Page 3-1, Par. 3.9) API 653 (Page 34, Par. 7.2.9) API 575 (Page 24, Par. 11.3.2.2) API 651 (Page 2, Par. 3.3) API 577 (Page 11-1, Par. 11.1.1) API 653 (Page 5-4, Par. 5.3.6.1) API 650 (Page 4-1, Par. 4.2.1.2) API 653 (Page 2, Par. 3.7) API 577 (Page 7-2, Par. 7.3.1) API 650 (Page 3, Par. 3.29) API 577 (Page 4-69, Par. 4.3.2.1) API 571 (Page 5, Par. 4.2.3) API 575 (Page C-1, Par. C.3.3.3) API 650 (Page 57, Par. 9.3) API 575 (Page 6-2, Par. 6.4.2.2) API 653 (Page 3, Par. 3.45) API 577 (Page 4-10, Par. 4.5.1.2a) API 653 (Page 6-2, Par. 6.4.2.1) API 653 (Page 5-4, Par. 5.3.4) API 650 (Page 4, Par. 3.70) API 577 (Page 7-1, Par. 7.3.1.2) API 653 (Page 4, Par. 3.67) API 577 (Page 3-1, Par. 3.10) API 653 (Page 3-6, Par. 3.5.2) API 650 (Page 7-1, Par. 7.3.1.3) API 653 (Page 4-6, Par. 4.3.5.3) API 653 (Page 6-1, Par. 6.3.1.2) API 653 (Page 4, Par. 3.52) API 577 (Page 6-3, Table 6-1) API 653 (Page 6-1, Par. 6.3.3.2) API 653 (Page 3, Par. 3.47) API 577 (Page 17, Par. 5.4) API 575 (Page D-1, Par. D.2.1a) API 653 (Page 5-1, Par. 5.2.1.4) API 650 (Page 6-1, Par. 6.3.3.2) API 653 (Page 8-1, Par. 8.2.2) API 653 (Page 4, Par. 3.54) API 577 (Page 3-1, Par. 3.1.1.1) API 650 (Page 4-1, Par. 4.2.4.3) API 653
95. 96. 97. 98. 99. 100. 101. 102. 103. 104. 105. 106. 107. 108. 109. 110. 111. 112. 113. 114. 115. 116. 117. 118. 119. 120. 121. 122. 123. 124. 125. 126. 127. 128. 129. 130. 131. 132. 133. 134. 135. 136. 137. 138. 139. 140. 141. 142. 143. 144.
2 1 2 1 3 1 1 4 3 3 4 2 2 4 2 1 3 3 3 1 2 2 2 4 4 1 2 4 2 4 3 2 2 1 1 2 1 3 2 1 2 3 4 2 4 3 1 2 3 4
(Page 3-13, Par. 3.7.2.1) API 650 (Page 1-1, Par. 1.1.3) API 653 (Page G-2, Par. G.5.1.1) API 653 (Page 2, Par. 3.15) API 577 (Page 6-3, Par. 6.1.5) API 650 (Page 10-4, Par. 10.5.5) API 653 (Page 2, Par. 3.17) API 577 (Page 3-1, Par. 3.1) API 653 (Page 6-3, Par. 6.1.2.9b) API 650 (Page 10-3, Par. 10.4.4.1) API 653 (Page 2, Par. 3.3) API 575 (Page 2, Par. 3.18) API 577 (Page 3, Par. 3.51) API 577 (Page 11-1, Par. 11.2.2) API 653 (Page 3-6, Par. 3.5.2) API 650 (Page 12-3, Par. 12.2.1.8) API 653 (Page 8, Par. 4.6) API 577 (Page 1-1, Par. 1.1.1) API 650 (Page 9-9, Par. 9.10.2.2) API 653 (Page 13-1, Par. 13.1.2) API 653 (Page 6-1, Par. 6.3.3.2b) API 653 (Page 8-1, Par. 8.4.1) API 653 (Page 8-1, Par. 8.4.2) API 653 (Page 9, Par. 5.1) API 577 (Page 9-5, Par. 9.8.6) API 653 (Page 1-3, Par. 1.3) API 650 (Page B-4, Par. B.2.3.1) API 653 (Page 12-3, Par. 12.3.2.1b) API 653 (Page B-1, Par. B.2.2.2) API 653 (Page 11, Par. 5.4.1) API 577 (Page 9-6, Par. 9.11.1.1) API 653 (Page 3, Par. 3.25) API 652 (Page 9-9, Par. 9.10.2.1.1) API 653 (Page 9-1, Par. 9.1.1) API 653 (Page 8-1, Par. 8.2.2) API 653 (Page 12-2, Par. 12.2.1) API 653 (Page 17, Par. 5.4) API 575 (Page 10-1, Par. 10.2) API 653 (Page 3-6, Par. 3.4.1) API 650 (Page 3-1, Par. 3.13) API 653 (Page 5-5, Par. 5.4.4) API 650 (Page 12-3, Par. 12.3.1a) API 653 (Page 5-2, Par. 5.2.3.1) API 650 (Page 12-5, Par. 12.4) API 653 (Page 6-4, Par. 6.3.2.5) API 650 (Page 3-50, Par. 3.10.4.6) API 650 (Page 8-1, Par. 8.1) API 653 (Page 2, Par. 3.2) API 651 (Page 2, Par. 3.6) API 651 (Page 3, Par. 3.22) API 652 Revised 01/07
145. 146. 147. 148. 149. 150.
3 2 4 2 1 4
(Page 6, Par. 4.2.2) API 651 (Page 14, Par. 6.2.1) API 651 (Page 6-1, Par. 6.3.2.1) API 653 (Page 7-1, Par. 7.4) API 653 (Forward Page iii) API 653 (Page 3-1, Par. 3.15) API 653
Revised 01/07
QW-482 SUGGESTED FORMAT FOR WELDING PROCEDURE SPECIFICATIONS (WPS) (See QW-200.1, Section IX, ASME Boiler and Pressure Vessel Code)
Company Name: BUBBA’S WELDING, INC. By: BUBBA SLAGLINE Welding Procedure Specification No. S M A W - 1 Date: 5 / 5 / 9 9 Supporting PQR No.(s) SMAW-A1 Revision No. Date: Welding Process(es): SMAW Type(s): ALL Automatic, Manual, Machine, or Semi-Auto
JOINTS (QW-402) Joint Design GROOVE Backing (Yes) (No) Backing Material (Type)
Details X
45O
(Refer to both backing and retainers) Metal Nonmetalic
Nonfusing Metal Other
Sketches, Production Drawings, Weld Symbols or Written Description should show the general arrangement of the parts to be welded. Where applicable, the root spacing and the details of weld groove may be specified.
1/8”
(At the option of the Mfgr., sketches may be attached to illustrate joint design, weld layers and bead sequence, e.g., for notch toughness procedures, for multiple process procedures, etc.)
*BASE METALS (QW-403) P-No. 1 Group No. 1 to P-No. 23 OR Specification type and grade to Specification type and grade OR Chem. Analysis and Mech. Prop. to Chem. Analysis and Mech. Prop. Thickness Range: Base Metal: Groove 1/8” – 1” U – 26” Pipe Dia. Range: Groove 1/2” Other: N *FILLER METALS (QW-404) Spec. No. (SFA) AWS No. (Class) F-No. A-No. Size of Filler Metals Weld Metal Thickness Range: Groove Fillet Electrode-Flux (Class) Flux Trade Name Consumable Insert Other
5.1 and 5.5 E-6010 3 3/32” 1 1/8”
E
2E 11 S
8
A
Group No.
Fillet Fillet
5.1 and 5.5 E-7018 4 1/16” – 7/32”
.250 N/A N/A N/A
2
1/32
1/2” N/A N/A N/A
*Each base metal-filler metal combination should be recorded individually
Read both this WPS and the attached PQR. Make the proper corrections based on ASME IX. HINT: This is a procedure for making a carbon steel pipe weld.
ITAC Practice WPS/PQR, Fall, 2001
Page 1
QW-482 (Back) WPS No. SMAW-1
POSITIONS (QW-405)
Rev. 0
POSTWELD HEAT TREATMENT (QW-407)
Position(s) of Groove FLAT Welding Progression: Up X Position(s) of Fillet
Temperature Range Time Range
Down
N/A N/A
GAS (QW-408) PREHEAT (QW-406)
Percent Composition Gas(es) (Mixture) Flow Rate 1 0 0o 3 0 0o Continuous
Preheat Temp. - Min. Interpass Temp. - Max. Preheat Maintenance
Shielding Trailing Backing
N/A
_______ ______ ______
________ ______ ______
(Continuous or special heating where applicable should be recorded)
ELECTRICAL CHARACTERISTICS (QW-409) Current AC or DC Amps (Range)
DC 10
Polarity
DCEN
Volts (Range)
1,000,000
(Amps and volts range should be recorded for each position, and thickness, etc. This information may be listed in a tabular form similar to that shown below. Tungsten Electrode Size and Type
N/A
Mode of Metal Transfer for GMAW
N/A
Electrode Wire feed speed range
N/A
(Pure Tungsten, 2% Thorated, etc.) (Spray arc, short-circuiting arc, etc.)
TECHNIQUE (QW-410) String or Weave Bead WEAVE ONLY Orifice or Gas Cup Size N/A Initial and Interpass Cleaning (Brushing, Grinding, etc.) Method of Back Gouging Oscillation Contact Tube to Work Distance Multiple or Single Pass (per side) Multiple or Single Electrodes Travel Speed (Range) 2 IPM Peening Root Only Other
Filler Metal
Weld Layer(s)
Process
Class
1
SMAW
E-7018
Dia. 1/8”
Current
Type Polar
Amp Range
DCEP
10 – 1K
Volt Range 75
Travel Speed Range
Other (e.g., Remarks, Comments, Hot Wire Addition, Technique, Torch Angle, Etc.)
2 IPM
ITAC Practice WPS/PQR, Fall, 2001
Page 2
QW-483 SUGGESTED FORMAT FOR PROCEDURE QUALIFICATION RECORD (PQR) (See QW-200.2, Section IX, ASME Boiler and Pressure Vessel Code) Record Actual Conditions Used to Weld Test Coupon Company Name BUBBA’S WELDING, INC. Procedure Qualification Record No. SMAW 1A WPS No. SMAW – 1 Welding Process(es) SMAW Types (Manual, Automatic, Semi-Auto.) MANUAL
Date 5 / 5 9 9
JOINTS (QW-402)
45o 1/8”
1/32” Groove Design of Test Coupon (For combination qualifications, the deposited weld metal thickness will be required for each filler metal or process used.)
BASE METALS (QW-403) Material Spec. A-53 Type or Grade B P. No. 1 to P-No. Thickness of Test Coupon 1/2” Diameter of Test Coupon 10” Other
POST WELD HEAT TREATMENT (QW-407) Temperature Time Other
1
GAS(QW-408)
FILLER METALS (QW-404) SFA Specification 5.5 AWS Classification E-6010 Filler Metal F-No. 3 Weld Metal Analysis A-No. Good Size of Filler Metal Other Weld Metal Thickness
1”
Ambient
5.1 E-7018 4 Good
1”
Shielding Trailing Backing
Gas(es) N/A
Percent Composition (Mixture) Flow Rate _______ ________ _______ ________ _______ ________
ELECTRICAL CHARACTERISTICS (QW-409) Current DC Polarity DCEN Amps. 120 Volts Tungsten Electrode Size 1/8 Other
POSITION (QW-405)
TECHNIQUE (QW-410)
Position of Groove Downhill Weld Progression (Uphill, Downhill) Other
Travel Speed 15 IPM String or Weave Bead String Oscillation Yes Multipass or Single Pass (per side) Single or Multiple Electrodes Other
PREHEAT (QW-406) Preheat Temp. Interpass Temp. Other
25
None
ITAC Practice WPS/PQR, Fall, 2001
Page 3
QW-483 (Back) PQR No.
SMAW 1A
Tensile Test (QW-150)
Specimen No.
Width
1
Thickness
2
1
Area
Ultimate Total Load lb.
2
75,000
Ultimate Unit Stress psi
Type of Failure & Location
85,000
GOOD
Guided-Bend Tests (QW-160) Type and Figure No.
Some Very Good
Others OK
Toughness Tests (QW-170) Specimen No.
Notch Location
Notch Type
Test Temp.
Impact Values
Lateral Exp. % Shear Mils
Drop Weight Break No Break
Fillet-Weld Test (QW-180) Result- Satisfactory: Macro - Results
Yes
No
Penetration into Parent Metal: Yes
No
Other Tests Type of Test Visual – As good as it gets! Deposit Analysis Other ...................................................................................................................................................... Welder’s Name I.B. WELDER Clock No. Tests conducted by: BUBBA’S WELDING, INC.
25 Stamp No. Laboratory Test No.
PU
We certify that the statements in this record are correct and that the test welds were prepared, welded, and tested in accordance with the requirements of Section IX of the ASME Code. Manufacturer Date
5/5/99
By
BUBBA’S WELDING, INC.
Bubba Slagline
(Detail of record of tests are illustrative only and may be modified to conform to the type and number of test required by the Code.)
ITAC Practice WPS/PQR Fall - 2001
Page 4
ITAC
Inspection Training And Consulting Post Office Box 5666 Pasadena, TX 77508-5666 Phone: 281-998-8305 Fax: 281-998-2163
Visit our website: www.itac.net
Significance of Last Digit of SMAW Identification Classification
Current
F-3 F-3 F-2 F-2 F-2 F-4 F-4 F-4 F-1 F-1 F-1 F-1
DCEP AC&DCEP AC&DCEN AC&DC AC&DC DCEP AC or DCEP AC or DCEP AC or DC AC or DC AC or DC AC or DCEP
EXX10 EXXX1 EXXX2 EXXX3 EXXX4 EXXX5 EXXX6 EXXX8 EXX20 EXX24 EXX27 EXX28
Arc Digging Digging Medium Light Light Medium Medium Medium Medium Light Medium Medium
Penetration Deep Deep Medium Light Light Medium Medium Medium Medium Light Medium Medium
Covering & Slag Cellulose-sodium Cellulose-potassium Rutile-sodium Rutile-potassium Rutile-Iron powder Low hyd.-sodium Low hyd.-potassium Low hyd.-iron powder Iron oxide-sodium Rutile-iron powder Iron oxide-iron powder Low hyd.-iron powder
Iron Powder 0-10% 0 0-10% 0-10% 25-40% 0 0 25-40% 0 50% 50% 50%
Note: Iron powder percentage based on weight of the covering.
SMAW Electrode Identification System Electrode lead Position
2 = Flat & Horizontal 1 = All
EXXXX
Positive
Strength
Coating/ Operating Characteristics
GMAW Electrode Identification System Chemical Composition
Strength
ERXXS - X
Work lead
Negative
Direct current electrode positive (reverse polarity)
Ground connection
Solid Wire
Electrode/Rod
Electrode lead FCAW Electrode Identification System Strength
Tubular
Positive
EXXT - X Position
Chemical Composition/ Operating Characteristics
0 = Flat & Horizontal 1 = All
Work lead Negative
Direct current electrode negative (straight polarity)
Ground connection
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Added Low Hydrogen Designators Don't Change Electrodes
by Dennis Hartman, Consumables Research and Development, The Lincoln Electric Company, Cleveland, Ohio Welders accustomed to using a low-hydrogen electrode with a particular classification are sometimes puzzled when they receive electrodes with added designations like “H4R.” Low-hydrogen electrodes are generally used in more critical applications to begin with, and their concern is understandable. However, it’s simply a case of the manufacturer providing more information on the same electrode as before. The added characters are optional designators, permitted by the AWS classification system, to clarify the low-hydrogen characteristics of carbon steel and low alloy steel manual electrodes. Nothing in the electrodes themselves has changed. Low hydrogen is defined as less than 16 milliliters (ml.) per 100 grams of weld metal. This classification has now been stratified into three levels, so the added designators make it easier to quickly determine how “dry” a particular electrode is. The levels are H16, H8, and H4, corresponding to 16, 8, and 4 ml. per 100 grams of weld metal. These represent the maximum diffusible hydrogen levels obtainable with a specific product. One additional designator may also be added. This is an optional moisture resistant designator (R), which indicates a low-hydrogen electrode’s ability to meet specific low-moisture pickup limits under controlled humidification tests. This generally indicates that the electrode’s coating has been formulated with non-hygroscopic materials and will resist picking up moisture longer than electrodes with standard low-hydrogen coatings. This can be important when welding in humid areas, since a standard coating will be affected by moisture in about two hours, while a moisture-resistant coating can be safe to use for as long as 10 hours. When these suffixes are used, they must be imprinted on the electrode itself, in addition to appearing on the label. The actual AWS classification does not change when they are added, however. For example, an E7018 H4R product will still be classified as E7018, although the product is identified by the full designation. With any low-hydrogen consumable, it is important to observe proper storage procedures. Products such as the H4 electrodes come in a hermetically sealed can. Once opened, they should be stored in a rod oven until used, since they may not meet specifications if left open in high humidity. In case of doubt about low-hydrogen electrodes and their application, the supplier should be consulted for recommendations.
