API 579 Fundamentals.pdf

API 579-1/ASME FFS-1 Fitness for Service Post-construction Code for Pressure Equipment with Flaws and Corrosion Damage. David C. Bennett, MS FTAPPI, Sr. Consultant Nathan Mixon, EIT, FFS Specialist Corrosion Probe, Inc., Centerbrook, CT 06409 Abstract Modern metal pressure equipment is designed and constructed according to ASME Boiler & Pressure Vessel code and ASME Piping codes to obtain safe operation through predictable material properties, specified stress limits and fabrication quality requirements. After an “authorized inspector” stamps completed equipment to signify it conforms to the code rules and has passed a final pressure test, the equipment is no longer covered by ASME B&PV codes. Instead, because equipment is subject to corrosion and other damage over time, N. American and European authorities have recently published standards prescribing standard methods for assessing the pressurized component’s fitness for continued service (FFS) precisely because compliance with design or new-construction codes often is not practical or economical. The owner uses the standardized FFS assessment methods to determine if the damage will lead to “failure” however that is defined, during the equipment’s projected service campaign in the service conditions. The stipulated FFS assessment methodology, entailing recognized engineering methods that can be independently validated, is codified in API 579-1/ASME FFS-1. This paper describes the fundamental intent and organization of this FFS post-construction code, using the example of assessing crack-like flaws from stress-assisted corrosion (aka waterside cracking) in a boiler tube, a damage mechanism that affects tubes in all types of boiler. FFS Technology Chronology Pressure equipment, initially mostly boilers in ships and factories, was increasingly used after the industrial revolution with very poor safety history. Because design and construction of early boilers was left up to individual manufacturers, failures and fatalities were common, peaking at a rate of around one per day, as shown in Figure 1.

Figure 1. Annual rates of boiler explosions in USA from 1880 to 1980: declines are attributed to adoption of ASME codes and standards for constructing boilers and pressure vessels.(1) The National Board of Boiler and Pressure Vessel Inspectors(2) was created in 1919 to promote greater safety to life and property through uniformity in construction, installation, repair, maintenance, and inspection of pressure equipment. During the past 90 years the National Board Inspection Code (NBIC, NB-23) provided rules and guidance for inspectors trained and certified by the National Board to carry out in-service inspections and approve repair and alteration of pressure vessels and pressure relief equipment. NBIC NB-23 describes how to inspect for general and

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localized thinning and pitting corrosion in the pressure boundary and for several cracking mechanisms, relying on sections of the ASME Boiler & Pressure Vessel (B&PV) code to define acceptance criteria for these different types of damage. The criteria involve simple rules about minimum allowed thickness and a general ban on cracks. However, in the last 30 years increased scientific analysis and engineering experience confirmed that pressurized components constructed to B&PV rules can safely tolerate substantial damage, depending on the local material and load conditions. This knowledge and experience spurred some industries - notably nuclear, petrochemical refining and chemical - to utilize their inherently higher levels of engineering resources for caring for pressurized equipment to devise consistent engineering procedures and assumptions for assessing the significance of damage that contravenes the rules of NB-23. The main impetus for creating these analytical tools came from the refining industry through the technical committees of the American Petroleum Institute (API)(3), which already had published industry standards aimed at safe operation of pressurized components and tanks, including ANSI/API 510, Pressure Vessel Inspection Code: Maintenance Inspection, Rating, Repair, and Alteration; ANSI/API 570, Piping Inspection Code: Inspection, Repair, Alteration, and Rerating of In-Service Piping Systems, and API 653, Tank Inspection, Repair, Alteration, and Reconstruction. These widely respected standards were the springboard for publishing documents for formally assessing the limits of in-service damage: API 571, Damage Mechanisms Affecting Fixed Equipment in the Refining Industry comprehensively describes all damage mechanisms including the controlling parameters, inspection methods and mitigation measures. API 579-1/ASME FFS-1, Fitness for service describes the procedures and rules for assessing if equipment with damage can be safely operated for a specified duration, or to prescribe the limits of tolerable damage for a particular piece of equipment under its operating conditions. First published in 2000, API 579, Recommended Practice for assessing fitness for service, represented a major advance in standardizing the methods for assessing the structural significance of cracks, mechanical damage, corrosion and fire or overheating damage in pressure equipment. Although API 579 placed emphasis on welded vessels and piping made from ferritic and austenitic steels and from aluminum alloys, the assessment procedures can be used to analyze equipment made from other metallic materials, as well as non-welded components or structures. API 579 evolved from fracture/fatigue assessment procedure PD6493, published 30 years ago in the UK to formalize rules for analyzing fabrication flaws and the need to repair them, thereby replacing arbitrary ‘workmanship’ rules. Initially adopted by the offshore industry, this modern approach to flaw assessment was subsequently recognized by safety authorities for application to pressure equipment. Recognizing the importance of a unified, rigorous methodology, in 2007 a joint ASME/API committee published API 579-1/ASME FFS-1, which incorporates input and acceptance from the National Board. A revised edition of API 579-1/ASME FFS-1 is expected in 2012. API 579-1/ASME FFS-1 not only provides a formal process for determining if pressure equipment with damage symptoms is fit for continued service, the title shows it is embraced by ASME as the post-construction code for pressure vessels built in accordance with the ASME B&PV Code. API 579-1/ASME FFS-1 also is endorsed and accepted by the National Board, which recognizes it as a powerful engineering tool for reconciling the often conflicting interests of owners who want to safely operate equipment with some corrosion or other damage, and jurisdictional inspectors who want the equipment removed from service because of the same damage symptoms. FFS assessment of a pressure vessel according to API 579-1/ASME FFS-1 involves rigorous engineering analysis of local materials and stress conditions at the damage location to determine if the damage dimensions exceed the limits for safe operation with standard code safety factor, allowing the owner to decide whether to continue operating the equipment, to monitor the damage, to repair the damage or retire the vessel. Guidance also is provided for determining when next and how to inspect the damage. Fundamentals of API 579-1/ASME FFS-1 An FFS assessment is an interdisciplinary analysis based on the following information: •

Knowledge of damage mechanisms and material behavior

•

Access to operating condition data; understanding parameters controlling damage mechanisms

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•

NDT (flaw sizing and location)

•

Material properties (environmental effects)

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Stress analysis (often finite element analysis)

•

Data analysis (engineering reliability models)

The FFS analysis is based on a fracture mechanics or a plastic collapse assessment of the flawed or damaged equipment. The owner must show that the flaw(s) or damage will not reach unacceptable dimensional limits during the specified next service period for the component under the specified service conditions. API 579-1/ASME FFS-1 principles apply to pressure vessels, piping and tanks constructed to the following codes: ASME BP&V Section VIII, Division 1 and 2 for pressure vessels, and Section 1 for boilers; ASME B31.1 & B31.3 for power and process piping; and API 620 and API 650 for storage tanks. FFS assessment principles also can apply to pressure equipment built to other recognized standards in the public domain and to proprietary “corporate” standards. Additionally, current editions of post-construction standards, such as API 653 (storage tanks), API 510 (pressure vessels) and API 570 (piping), reference and/or include some basic aspects of, API 579-1/ASME FFS-1. Organization of API 579-1/ASME FFS-1 1,280 pages of API 579-1/ASME FFS-1 are organized in the following 13 Parts and 10 Annexes: Part 1: Introduction Part 2: Fitness-For Service Engineering Assessment Procedure Part 3: Assessment of Existing Equipment for Brittle Fracture Part 4: Assessment of General Metal Loss Part 5: Assessment of Local Metal Loss Part 6: Assessment of Pitting Corrosion Part 7: Assessment of Hydrogen Blisters and Hydrogen Damage HIC & SOHIC Part 8: Assessment of Weld Misalignment and Shell Distortions Part 9: Assessment of Crack-Like Flaws Part 10: Assessment of Components Operating in Creep Regime Part 11: Assessment of Fire Damage Part 12: Assessment of Dent, Gouges, and Dent-Gouge Combinations Part 13: Assessment of Laminations Annex A - has thickness, MAWP and membrane stress equations. Annex B - is an overview of how to analyze stresses Annex C - is a collection of stress intensity factor solutions Annex D - is a compendium of reference stress solutions. Annex E - covers residual stresses mostly from welding Annex F - shows how to incorporate material properties in the assessment Annex G - discusses damage/deterioration and failure modes Annex H - emphasizes the importance of validating assessment results Annex I - is a glossary of terms and definitions Annex J - presently is blank Annex K - reviews concepts related to crack opening areas Although the document essentially stands alone, assessments also use material properties and design information from the original ASME/API construction codes. FFS assessment generally entails the following procedural steps: Step 1 – Flaw/condition identification - defining the damage mechanisms and mode of failure Step 2 – Applicability and limitations of the assessment Step 3 – Data required - type of inspection data required to perform the assessment Step 4 – Assessment techniques and acceptance criteria calculations Step 5 – Remaining life evaluation

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Step 6 – Remediation considerations - slowing the flaw growth rate Step 7 – In-service monitoring to validate assessment decisions, etc. Step 8 – Documentation - reports as to how the assessment technique was developed Three assessment levels API 579-1/ASME FFS-1 has three assessment levels: each higher level assessments uses more detailed stress information, more accurate characterization of the type of damage, and more specific materials’ property data to generate increasingly less conservative assessment results. Level 1 - Most conservative assessment (rationale similar to NBIC 23) • Basic damage sizing (inspection) and component information • Can be done by a trained “FFS inspector” Level 2 - More detailed assessment produces less conservative results; Level 1 requirements, plus: • Accurate damage sizing and growth rate • More comprehensive knowledge of damage mechanism rate controlling parameters • Qualified engineering skill in FFS methods and procedures Level 3 - Most detailed and least conservative results; Level 2 requirements, plus: • Highest detail in damage sizing; materials and component service data • Local material properties • Numerical stress and temperature analysis techniques, including finite element methods Damage characterization The damage mechanism(s) must be identified and understood, using industry references like API 571, Damage Mechanisms Affecting Fixed Equipment in the Refining Industry, and WRB 488, Damage Mechanisms Affecting Fixed Equipment in the Pulp and Paper Industry.(4) Inspections to characterize the shape and to size the damage must be supervised by engineering specialists experienced with nondestructive testing methods and limitations. API 5791/ASME FFS-1 strongly emphasizes validation by requiring that every NDT procedure be written (to permit subsequent retesting to monitor the damage), and also be qualified to confirm the test sensitivity before work-face testing is done. For practitioners, Level 1 FFS inspectors should have relevant fitness-for-service knowledge and training and may have API 510, 570, or 653 “certification”. FFS engineers are expected to have an engineering degree and at least two years of relevant mechanical or materials engineering training and experience. Assessment methods generally use one or more of three fundamental acceptance criteria: allowable stress; remaining strength factor (RSF); and failure assessment diagram (FAD). The majority of API 579-1/ASME FFS-1 is based on RSF and FAD acceptance criteria. A frequently used criterion for most types of flaw assessments is RSF, which is the ratio of the limit or plastic collapse load for a damaged component to that of an identical, undamaged component. The FAD evaluates whether a crack-like flaw of known shape and size acted on by the postulated stress conditions will fail either due to unstable crack growth (brittle fracture) depending on the metal toughness, or due to exceeding the limit load for plastic collapse (ductile failure), on the y and x axes of the FAD, respectively. API 579-1/ASME FFS-1, Part 9, Assessment of Crack-Like Flaws covers planar cracks, weld lack of fusion and lack of penetration, sharply shaped corrosion or mechanical grooves, etc. Flaws that may end up being assessed as cracks include aligned porosity or inclusions and deep weld undercuts. Data required for assessment include flaw length and depth and material properties listed in Annex F. The following example illustrates Level 2 assessment of stress-assisted corrosion (SAC, aka. waterside cracking) (5) on the internal surface of an internally pressurized, steel boiler tube - a damage mechanism that occurs in water and steam-filled steel tubes in many types of boilers. Example of FFS assessment of SAC in a boiler tube

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SAC produces cracks on the internal surface of a boiler tube when the protective magnetite scale fractures due to local strain, and oxygen-supported corrosion of the exposed steel produces a network of blunt cracks perpendicular to the highest strain. Important characteristics of SAC damage for FFS analysis are the multiple, mostly parallel cracks; crack length significantly greater than depth; and cracking in or near the footprint of external welded attachments or at substantial stiffness transitions in the tube. Figure 2 shows classic evidence of SAC in the ‘footprint’ of an external attachment in a boiler tube, along with the blunt-tipped, crack-like flaws. Other important factors are the dominance of hoop stress from internal pressure and minimum residual stress at the internal surface.

Figure 2. Classic crack network from SAC inside a carbon steel boiler tube (left), with cross-sections (right) showing their typical blunted tip shapes. FFS analysis for a boiler tube with SAC starts with deciding whether to use Part 4, Part 5, or Part 9. Using rules in Part 9 for multiple cracks (the most conservative conditions, confirmed by analyzing other scenarios), the damage is treated as interacting, axial crack-like flaws, close enough to each other to be treated as interacting by rules in API 579-1/ASME FFS-1. Of two options for integrating multiple interacting cracks of similar depth, damage consequences are more severe when the network of cracks is assessed as a single, crack-like flaw with length and depth defined by the overlapping projection rules and oriented perpendicular to the primary (hoop) stress. The modeled crack is located in the tube crown to be least affected by the reinforcing effect of external welds, including membrane welds in this tube. This scenario is illustrated in Figure 3. A less conservative option is to circle the cracks in an area of local metal loss, with dimensions defined by the boundary of the cracked tube volume. Analyzing the damage as a singular, infinitely-long, axial crack according to Part 9, Level 2 procedures: •

Overriding the < 2.5 mm thickness limitation that requires Level 3 assessment because ASME minimum wall thickness is 1.75 mm

•

With the local 800 psi tube pressure in the tube

•

Taking the lowest temperature when crack-opening force is greatest, i.e., tube is pressurized, into consideration for notch toughness.

•

Estimating (or modeling) the possible reinforcing effect and residual stresses associated with membrane welds attachments, as well as secondary forces, such as axial loads

the results show the crack could be 0.158” deep (79% through the 0.200” wall) before the tube damage fails to meet Part 9, Level 2 assessment criteria for safe continued operation.

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Figure 3. Drawing of infinitely long, axial, internal crack in crown of floor tube resulting from API 579-1/ASME FFS-1 rule for interacting cracks Other boiler tube damage that has been assessed for FFS per API 579-1/ASME FFS-1 includes external corrosion along tangent lines, near-drum corrosion, and severe ‘divots’ under the studs (recovery boiler) revealed in tubes removed for other reasons. Summary •

API 579-1/ASME FFS-1, published in 2007, describes methods and procedures intended to supplement the requirements in API 510, API 570, API 653, and NB-23 to provide post-construction code rules for assessing the Fitness-for-Service of equipment designed and constructed to recognized codes and standards, including international and internal corporate standards.

•

The standard has broad application since the assessment procedures are based on allowable stress methods and plastic collapse loads for non-crack-like flaws, and the Failure Assessment Diagram (FAD) Approach for cracklike flaws. The FFS assessment procedures in the standard can be used to evaluate corrosion and other servicerelated damage encountered in pressure vessels, piping and tanks.

•

A case example is provided in which API 579-1/ASME FFS-1Part 9, Level 2 FFS assessment criteria are used to determine the theoretical limiting depth for a continuous, infinitely-long, axial crack representing SAC in the fireside of a 50 mm OD., 5 mm w.t., carbon steel boiler tube in the floor panel of a recovery boiler.

References 1. "Practical Guide to ASME B31.3 Process Piping" 2nd Ed., G.E. Woods and R.B. Baguley CASTI Publishing Company. Edmonton, AB (2000) ISBN 0-07-136471-4 2. National Board 3. API 4. Welding Research Council WRB 488 5. Ref. www.tappi.org/Downloads/Conference-apers/2006/06EPE-Conference/06EPE41.aspx

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Fitness-for-service: ASME Post-construction Codes and Committees Assessing Fitness-for-Service (FFS) of Fixed Equipment with API/ASME Standard API 579-1/ASME FFS-1 David C. Bennett, MS, FTAPPI Sr. Consultant Corrosion Probe Inc. Centerbrook, CT 06409 www.cpiengineering.com PEERS 2011 Page 1583

Fitness-for-service and Post-construction codes

Overview of Code and Standards for Pressurized Equipment ASME B&PV Code

80+ years in development

API 571

API 580/581

API 579

PCC-2; PCC-3 PEERS 2011 Page 1584

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Presentation outline 1. 2. 3. 4.

What is a Fitness-For-Service (FFS) assessment? What types of equipment get FFS assessments? When are FFS assessments justified? Chronology of FFS code & post-construction standards

5. Scope of API/ASME Standard API 579-1 /ASME FFS-1 6. FFS methodology per API 579-1 /ASME FFS-1 7. Example - boiler tube with waterside cracking (SAC)

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1. Define a Fitness-for-Service assessment Quantitative engineering analysis, using standard rules and methods - to determine if in-service equipment is reliable and safe to operate (with regular factors of safety) - under clearly defined service condition limits - for a specified time.

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2. To what equipment does FFS assessment apply? Containment, mechanical integrity, asset management • On pressure vessels complying with ASME new-construction codes. • Fixed equipment with known damage mechanisms, including tanks (API 653 includes FFS), piping, boilers, stacks, FRP, etc. • All types of fixed equipment for which a quantitative “failure condition” can be specified under known service conditions.

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3. What justifies an FFS assessments? • • • •

If the asset lacks orig. design information or has exceeded its useful life If the asset’s service is changed If the asset undergoes an event that could affect its serviceability and shape: overload, new process/external environment, overheat, fire! If inspection finds damage that could affects the asset’s future reliability: corrosion, cracking, distortion (misalignment, bulges, dents), etc.

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4. Chronology of FFS Std. & ASME post-construction code • In 1991 Materials Properties Council initiated Group Sponsored Project: original scope - evaluate fitness for service of pressurized equipment in the refinery & petrochemical industry, then extend to other industries. • In 2000, First edition of API Recommended Practice API RP579, Assessment of Fitness for service, applied to the following items:

– Equipment designed and constructed to ASME B&PV Code, Section I and Section VIII, Divisions 1 and 2 – Piping designed to ANSI/ASME B31.1 and 31.3 piping codes – Storage tanks designed and constructed to API 620 and API 650 codes

• In 2003 the ASME/API Joint Committee was formed to produce a “post-construction code”

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4. Chronology of FFS Stds & ASME Post-construction code • In 2007 the ASME/API Joint Committee published ASME/API Standard API 579-1/ASME FFS-1, Fitness-for-service • In 2009 the ASME/API Joint Committee published ‘example problems’ in API 579-2/ASME FFS-2 • Since 2000 ASME Post-construction Committees (PCC) published

– Standard PCC-1-2000, Guidelines for Pressure Boundary Bolted Flange Joint Assembly – Standard PCC-2-2009, Repair of Pressure Equipment and Piping – Standard PCC-3-2007 Inspection Planning Using Risk-Based Methods

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Presentation outline recap 1. 2. 3. 4.

What is a Fitness-For-Service (FFS) assessment? What types of equipment get FFS assessments? When are FFS assessments justified? Chronology of FFS code & post-construction standards

5. Scope of API/ASME Standard API 579-1 /ASME FFS-1 6. FFS methodology per API 579-1 /ASME FFS-1 7. Example - boiler tube with waterside cracking (SAC)

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5.1 Scope of API 579-1/ASME FFS-1 Covers assessment or re-rating of equipment designed and constructed to: • • • • • •

ASME B&PV Codes Section VIII Division 1 & 2 ASME B&PV Code Section I ANSI/ASME B31.1 Power piping code and B31.3 Process piping code API 650 and API 620 Tank construction standards Other recognized codes and standards, including international standards (review attributes/compare to API & ASME codes) Methods and procedures supplement API 510, API 570 and API 653

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5.2 Scope of API 579-1/ASME FFS-1 Personnel - Accountability and Responsibility 1.

The owner-user is responsible for the integrity/validity of the assessment procedures.

2.

The inspector must provide reliable inspection data and generally ensure that requirements of applicable owner-user or API inspection procedures and practices are followed. Inspectors may perform some Level 1 screening analyses, and must ensure the assessment results are recorded and filed. The inspector can be qualified per API codes.

3.

The engineer – not required to be employee - is responsible for most assessment work, including review of screening analyses performed by the inspector. The engineer should have at least two years of relevant experience.

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5.3 Parts of API 579-1/ASME FFS-1

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5.4 Parts of API 579-1/ASME FFS-1

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6.1 API 579-1/ASME FFS-1 methodology Relevant parts

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6.2 API 579-1/ASME FFS-1 methodology

Assessment levels Level 1

Level 2

Level 3

– Minimum amount of inspection or component information – Conservative screening - general concurrence with NBIC rules – Plant inspection or engineering personnel – More detailed, less conservative with more accurate results based on local stresses and material properties – Quantitative damage characterization – size, shape, location, orientation – Qualified engineering personnel – Most detailed evaluation – requires very detailed inspection and component information – Analysis procedures are based on material testing and/or numerical analysis techniques such as the finite element method – Personnel with expertise in complex FFS assessments

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6. API 579-1/ASME FFS-1 methodology

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6.3 Regular API 579-1/ASME FFS-1 methodology Step 1 – Flaw/Condition Identification (Mode of Failure) Step 2 - Applicability and Limitations Step 3 - Data Requirements 3.1 Original Equipment Design Data 3.2 Maintenance and Operational History 3.3 Data/Measurements required for FFS assessment 3.3 Qualified inspection procedures for size acceptance criteria

Step 4 - Assessment Techniques and Acceptance Criteria 4.1 Local stress approach to assess wall loss and corrosion flaws. 4.2 Linear elastic stress analysis (toughness vs. load) for a crack-like flaw.

Step 5 - Remaining Life Evaluation Step 6 - Remediation Step 7 - In-Service Monitoring Step 8 - Documentation

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6.4. Owner Benefits from FFS Formal engineering assessment methods for aged equipment, using real service conditions and material properties delivers: – Safer and more reliable fixed equipment – Reduced downtime - wasteful inspections and repairs are eliminated – Optimized inspection scope and timing based on confirmed damage mechanisms and rates – SID Program incorporates FFS – Supports “defect elimination” (RCFA) discipline and procedures – mitigation is designed for specified time of service At least 10% reduction in maintenance costs

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ASME Post Construction Committees Three ASME Post-construction Committees: Subcommittee on Bolted Joint Assembly – Issued PCC-1, 2000, Guidelines for Pressure Boundary Bolted Flange Joint Assembly, next edition in preparation Subcommittee on Repair and Testing – Issued PCC-2, Repair of Pressure Equipment and Piping; 2006 and 2009 editions Subcommittee on Inspection Planning – Issued PCC-3, Inspection Planning, first edition in 2008

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FFS example 1 – Waterside cracking (SAC) corrosion fatigue in boiler tubes Damage mechanism and description

Level 2 Assessment per Part 9 - Crack-like flaws

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FFS example 1 – Waterside cracking (SAC, corrosion fatigue) in boiler tube • 2.0 “ OD 0.200” wall thickness • Multiple crack interaction is modeled as a “worst-case”, single, full-length crack of uniform depth • 800 psi internal pressure means hoop stress is primary ‘load’ • 550°F - 100 ksi√in notch toughness • Fracture Assessment Diagram (FAD)

The crack is unstable (i.e., grows at unacceptable rate) when it is 78% through the wall.

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FFS example 2 – Under-stud weld cavitis in recovery boiler tubes Damage mechanism and description Level 2 assessment per Part 5 – Local thin area or gouge • 3.0 “ OD, 0.200” wall thickness • damage is modeled as local thin area (LTA) • 660 psi internal pressure makes hoop stress the primary ‘load’ • 520°F gives 100 ksi√in notch toughness - only yielding is concern • Stress limits exceeded only if the divots leave 0.034” remaining ligament

Validation: NBIC pitting allowance; ASME non-reinforcement of nozzle hole; pressure test actual tube specimens PEERS 2011 Page 1604

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Organization of Standard PCC-2 PCC-2 standard describes “recognized and generally accepted, recommended engineering practice” for repairing pressure equipment & piping already in service • • • • •

Part I covers Scope, Organization and Intent Part 2: Welded Repairs Part 3: Mechanical Repairs Part 4: Nonmetallic and Bonded Repairs Part 5: Examination and Testing

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Organization of Standard PCC-2 Standard Format for Each Article: • Description of the repair • Limitations and Precautions associated with the repair • Design/Fabrication issues associated with the repair • Examination and Testing QA/QC practices following the repair • Additional references

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Summary The API 579-1/ASME FFS-1 post-construction code and related ASME Post construction committee (PCC) standards incorporate fitness for service methodology to provide modern engineering tools allowing the owner of fixed equipment to challenge the traditional “code requirement” to restore aged and corroded pressure vessels, piping and tanks to “as new” conditions defined in ASME Section VIII, the new-construction code. FFS assessment methods permit condition limit criteria to be calculated for equipment subject to corrosion and other damage, including damage from mechanical impact and fire. ASME PCC-2 Standard describes many repair methods for damaged codecompliant pressure vessels and piping – the concept of a “code repairs” is finally realized.

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Thank you for your interest and attention.

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