Procedure for Piping Stres Analysis Offshore)

308-7080-ST-54-102 Page 1 of 26

HALLIBURTON KBR

Procedure for Piping Stress Analysis (Offshore) Document Number 308-7080-ST-54-102

______________________________________________________________________

PROPRIETARY INFORMATION This document contains proprietary information belonging to Halliburton KBR and may neither be wholly or partially reproduced nor be disclosed without the prior written permission of Halliburton KBR.

PROCEDURE FOR PIPING STRESS ANALYSIS 308-7080-ST-54-102 (OFFSHORE) Page 2 of 26 ____________________________________________________________________________

REVISION RECORD

Rev. Date Description By Check. Review App. _____________________________________________________________________ D1 15/11/99 Draughted MO D2 18/10/00 Checked PR D3 13/06/01 Reviewed RT D4 24/04/02 Issued for Use MO PR RT IB

_______________________________________________________________________ DOCUMENT RESPONSIBILITY The Piping Department Manager is responsible for authorisation of revisions of this document.

PROCEDURE FOR PIPING STRESS ANALYSIS 308-7080-ST-54-102 (OFFSHORE) Page 3 of 26 ____________________________________________________________________________ CONTENTS 1.0

PURPOSE

2.0

SCOPE

3.0

REFERENCES

3.1 3.2

Applicable Codes, Standards and Regulations Other Requirements

4.0

PROCEDURES

4.1 4.2 4.3 4.4 4.5 4.6 4.7 4.8 4.9 4.10 4.11 4.12

System of Units Critical Line List Stress Isometric Index Studies Stress Isometrics Piping General Arrangement Drawings Stress Calculations Supplier Drawings and Data Approval of Nozzle Loads Piping Isometric Drawings for Construction Pipe Supports Offshore Riser and Topsides Piping Interface

5.0

DESIGN

5.1 5.2 5.3 5.4 5.5 5.6 5.7 5.8 5.9 5.10 5.11

Design Conditions Stress Limitations External Loads Loads Applied to Mechanical Equipment Design and Analysis of Flanged Joints Clamp Connectors External Loads Due to Blast Over pressure Use of Fabricated Lateral Connections in Process Piping High Strength Stainless Steels Use of Mechanical Joints Transportation Loads

PROCEDURE FOR PIPING STRESS ANALYSIS 308-7080-ST-54-102 (OFFSHORE) Page 4 of 26 ____________________________________________________________________________

6.0

ATTACHMENTS Attachment 1

Overview of Caesar II Program

Attachment 2

Requirements for Stress Isometrics

Attachment 3

Typical Stress Isometric

Attachment 4

Restraint Symbols for Stress Isometrics

Attachment 5

Flow-Chart for Stress Analysis

PROCEDURE FOR PIPING STRESS ANALYSIS 308-7080-ST-54-102 (OFFSHORE) Page 5 of 26 ____________________________________________________________________________ 1.0

PURPOSE This procedure provides an overview of piping stress department activities, with particular regard to the information interface with other sections and disciplines. In addition, requirements are outlined for engineering of piping systems, with regard to internal and external effects upon the piping and connected equipment. Further advice regarding working practice and calculation methods is available in Stress Analysis Working Methods, document No. 308-7080-ST-54-104. This Corporate Document may be renumbered and revised to suit specific Project requirements.

2.0

SCOPE

2.1

The document is applicable to offshore platform design.

2.2

The objective of piping stress analysis is to obtain a safe and economical layout for piping elements whilst ensuring that the following is prevented: (i)

Piping stresses in excess of those permitted by the referenced Codes and Standards (Ref. Section 3.1 and 3.2).

(ii)

Leakage at Joints.

(iii)

Excessive forces and moments applied to connected equipment.

(iv)

Excessive stresses in the supporting or restraining elements.

(v)

Unintentional disengagement of piping from its supports.

(vi)

Excessive interference with thermal expansion or contraction of the piping system or connected equipment.

(vii)

Resonance due to externally imposed vibrations or fluid induced vibrations.

PROCEDURE FOR PIPING STRESS ANALYSIS 308-7080-ST-54-102 (OFFSHORE) Page 6 of 26 ____________________________________________________________________________ (viii) Excessive sag in piping spans, particularly those requiring a drainage slope.

2.3

3.0

(ix)

Damage to piping or components due to strain during jacking to remove or install blinds for isolation.

(x)

Fatigue Failure due to high cycle loading not covered in ASME B31.3 e.g. wave induced displacements of bridge pipework.

It is the responsibility of the stress section to perform the following activities:(i)

Carry out the necessary calculations to ensure that all loading conditions that may be experienced by a piping system are considered and catered for within the design.

(ii)

Ensure that piping systems comply fully with the stress analysis requirements specified by the Codes and Standards listed in Section 3.1 and 3.2.

(iii)

Issue approved stress isometrics for critical lines as required.

(iv)

Prepare a Stress Analysis Report containing calculations and information for each piping system analysed, at the end of the project.

REFERENCES 308-7080-ST-51-120

Procedure for Piping Design

308-7080-ST-51-122

Piping Materials Specification Narrative

(PROJECT SPECIFIC)

Process Line List

(PROJECT SPECIFIC)

Design Premise (Environmental Data)

308-7080-ST-54-101

Specification for Equipment Nozzle Loading due to Piping Reactions.

308-7080-ST-54-103

Critical Line List Procedure

PROCEDURE FOR PIPING STRESS ANALYSIS 308-7080-ST-54-102 (OFFSHORE) Page 7 of 26 ____________________________________________________________________________

3.1

308-7080-ST-54-105

Recommended Installation and Hook-up Procedure for Piping Connected to Rotating Compressors and large Pumps

PCM-WWBV-EN-077

Preparation control and approval of calculations

PCM-WWBV-EN-002

Validation and approval of Design Documents

Applicable Codes, Standards and Regulations. Piping arrangements and piping stress analysis shall be in accordance with the requirements specified in the latest edition of codes and standards listed below:ASME B31.3 Chemical Plant and Petroleum Refinery Piping Client Specifications and Procedures as applicable

3.2

Other Requirements In addition to ANSI B31.3 and its sub-references, other codes may govern the design and installation of some parts of a piping system. Examples of pertinent codes are:ANSI B31.1 Power Piping Code ANSI B16.5 Steel Pipe Flanges and Fittings ASME VIII Pressure Vessel and Boiler Code (Div.1 & Div 2) BS 5500 Unfired Fusion Welded Pressure Vessels BS 8010 Pt 3. Code of Practice for Pipelines NEMA SM-23Multi-stage Steam Turbines for Mechanical Drive Service MSS SP44 Steel Pipe Line Flanges API RP-2A Planning, Design and Construction of Fixed Offshore Platforms API RP-14E Design and Installation of Offshore Production Platform Piping Systems API RP-520 Recommended Practice for Design of Pressure Relieving Systems API 605 Large Diameter Carbon Steel Flanges

PROCEDURE FOR PIPING STRESS ANALYSIS 308-7080-ST-54-102 (OFFSHORE) Page 8 of 26 ____________________________________________________________________________ API 610 API 617 API 618 API 650 API 660 API 661 DOE DNV

Centrifugal Pumps for General Refinery Service Centrifugal Compressors for General Refinery Service Reciprocating Compressors for General Refinery Service Welded Steel Tanks for Oil Storage Heat Exchangers for General refinery Service Air Cooled Heat Exchangers for General Refinery Service Department of Energy - Offshore Installation Guidelines on Design and Construction Note 30.2 - Det Norsk Veritas - Fatigue Strength Analysis for Mobile Offshore Structures

Any such codes affecting the piping shall be noted on Stress isometrics. Should a conflict occur between this Procedure and referred codes then the most stringent requirements shall apply. 4.0

PROCEDURES

4.1

System of Units The SI system of units shall normally be used. Pipe nominal diameter and wall thickness may be expressed in English units.

4.2

Critical Line List Critical Line selection and control shall be in accordance with procedures outlined in following document: 308-7080-ST-54-103 Critical Line Selection Procedure.

4.3

Stress Isometric Index Generation and use of the Stress Isometric Index is closely allied to selection of critical lines and is outlined in the Critical Line Selection Procedure.

PROCEDURE FOR PIPING STRESS ANALYSIS 308-7080-ST-54-102 (OFFSHORE) Page 9 of 26 ____________________________________________________________________________ 4.4

Studies The stress section shall review and comment on all piping studies that include critical lines. The stress section may define approximate locations of major pipe supports and restraints, including spring support locations and vessel attachments for pipe support purposes, with the assistance of the pipe supports section. Where appropriate, loading on equipment and superstructure shall also be determined. Locations of fixed and sliding ends of horizontal vessels and equipment shall be defined where appropriate. One print of each piping study with the issue date is required for review. This print shall be commented upon, signed, dated and retained in stress section files. A copy with comments shall be returned to the piping section.

4.5

Stress Isometrics 4.5.1

Initial Issue and Approval The stress section shall issue a critical line list (Ref. section 4.2) indicating lines to be shown on stress isometrics. Stress isometrics shall be produced in accordance with the guidelines presented in Attachment 2. The stress engineer shall add to the original any minor routing changes agreed with piping and pipe supports sections, all restraint data, reference nodes, calculated results and notes. The original shall be approved, signed and dated by the stress engineer. The lead stress engineer shall review and issue each completed stress isometric in accordance with the distribution below. If major re-routing of a piping system is required by the stress engineer, the original shall be updated and reissued as above. The lead stress engineer shall agree such action with the relevant piping section leader.

PROCEDURE FOR PIPING STRESS ANALYSIS 308-7080-ST-54-102 (OFFSHORE) Page 10 of 26 ____________________________________________________________________________ 4.5.2

Changes to Approved Stress Isometrics A single master file of stress isometrics shall be retained in the stress section. All changes to critical lines MUST be marked up on the master, signed and dated. The lead stress engineer MUST be informed of all such changes. The lead stress engineer shall, in conjunction with the area piping section leader and the originating stress engineer, make a decision as to whether re-calculation is required. If so the original stress isometric shall be revised and reissued as above. If a new calculation is not required, the lead stress engineer shall annotate the master to this effect. Prior to incorporation of stress isometrics in final stress reports, all such comments shall be transferred to the original, including "calculations valid".

4.5.3

Distribution of Stress Isometrics Following approval, the stress isometrics shall be distributed as follows:1 copy to piping section leader 1 copy to pipe supports section leader 1 copy to mechanical group, if piping loads are in excess of those stated in Specification "Loading on Equipment Nozzles due to Piping Reactions", or in the case where allowables lower than those stated have been agreed with a vendor. 1 copy to (stress section) master file. The pipe supports group may distribute approved stress isometrics to structural and civil sections to aid definition of support loads if required. The original shall be retained by the stress section. When a revised stress isometric is issued, the previous issue master file copy shall be stamped 'VOID - SEE LATER ISSUE' and retained in the stress isometric file. Refer to Flowchart, Attachment 5.

PROCEDURE FOR PIPING STRESS ANALYSIS 308-7080-ST-54-102 (OFFSHORE) Page 11 of 26 ____________________________________________________________________________ 4.6

Piping General Arrangement Drawings

4.7

All piping G.A.'s containing critical lines shall be reviewed by the stress section prior to issue of each revision in order to ensure that stress analysis requirements, as shown on the stress isometrics have been incorporated in the completed design. One print of each piping G.A. is required for review which shall be commented upon if necessary. Stress Calculations The CAESAR II computer program (ref. Attachment 1) shall be used for comprehensive stress calculations. Where less extensive calculations are appropriate, simplified methods such as 'Spielvogel' chart form solutions, guided cantilever approximation or visual inspection shall be used. Flexibility analysis shall consider the most severe temperature condition found during start-up, normal operation, shut-down, regeneration or steam-out, or any other condition that may realistically occur. Proper consideration shall be given to temperature excursions and operational combinations, such as those found in multiple pumps and compressors linked to a common header. The base case for flexibility analysis shall be "as installed", essentially stress free with the exception of self weight. Appropriate primary and secondary stress cases and special cases, such as settlement and dynamic or transient loads shall be evaluated as required. Special consideration shall be given to piping systems in the following categories. (i)

Lines subjected to significant differential deflection due to settlement of supports, movement of tank walls, equipment displacement and those lines crossing an inter-platform bridge.

(ii)

Category M fluid service as defined by ASME B31.3.

(iii)

Lines subjected to two-phase flow or slugging.

(iv)

Lines subjected to external pressure, either due to internal vacuum or jacketting.

PROCEDURE FOR PIPING STRESS ANALYSIS 308-7080-ST-54-102 (OFFSHORE) Page 12 of 26 ____________________________________________________________________________ (v)

4.8

Lines subjected to vibration, either by attached equipment or due to flow conditions. Supplier Drawings and Data The stress section shall review and comment on all Supplier drawings of equipment and vessels. The lead piping engineer shall ensure that the stress section is included in the IDC circulation and further issues of Supplier drawings and data.

4.9

Approval of Nozzle Loads Piping loads applied to mechanical equipment shall normally meet the requirements of Specification for Equipment Nozzle Loading Due to Piping Reactions, Document No. 308-7080-ST-54-101. Approval of any loads applied to equipment nozzles greater than those indicated in the above specification shall be obtained in writing from the equipment Supplier by the Mechanical Department. In the case where allowable loads lower than those indicated have been agreed with a Supplier, documentary evidence of the revised allowables loads shall be filed with the relevant stress isometrics for inclusion in Stress Analysis Reports. In all cases, applied nozzle loads and respective allowables shall be identified on the stress isometric, or reference to a load calculation shall be made.

4.10

Piping Isometric Drawings for Construction The stress section shall review and comment if necessary, prior to the issue of each revision, on all piping isometrics. Checks shall be made to ensure that the system conforms to stress analysis requirements.

4.11

Pipe Supports 4.11.1 Issue of Pipe Support Drawings Special supports such as those associated with rotating equipment or attached to pressure vessels shall be carefully scrutinised with regard to fitness for purpose.

PROCEDURE FOR PIPING STRESS ANALYSIS 308-7080-ST-54-102 (OFFSHORE) Page 13 of 26 ____________________________________________________________________________ 4.11.2 Standard Supports The support section shall check and approve all standard designs and shall retain records of all calculations.

pipe support

4.11.3 Spring Supports Spring supports shall be used to accommodate vertical pipe displacements whilst controlling dead-weight reactions. Spring locations shall be defined by the stress section. Spring design data sheets shall be completed by the supports section and reviewed by the stress section. Certified valve weights shall be used for final approval of spring support data sheets. 4.11.4 Special Support Elements Special pipe support elements such as shock arrestors and snubbers shall be specified by the stress section and detailed by the supports section. 4.12

Offshore Riser and Topsides Piping Interface There will normally be an overlap in analysis by the topsides sections and Pipelines group of risers, associated piping and receivers or launchers. The pipe stress section shall model risers down to the dead-weight support, and the Pipelines group shall include piping up to the launcher or receiver in their model. The piping stress section shall issue to the Pipelines Department a stress isometric indicating location and type of restraints required for the topsides portion of the riser. For confirmation, the pipelines group shall provide a copy of their isometric indicating similar locations prior to analysis. Subsequent to their analysis the Pipelines Department shall issue to the piping stress section their approved stress isometric of the riser plus topsides piping together with a summary stress report for all load cases considered. This report must contain at least the following:-

PROCEDURE FOR PIPING STRESS ANALYSIS 308-7080-ST-54-102 (OFFSHORE) Page 14 of 26 ____________________________________________________________________________

i)

Maximum calculated stresses with corresponding Design Code compliance allowable stresses.

ii)

Forces and moments at topsides supports (restraint loads).

iii)

Forces and moments at flange connections and butt weld valves (data points located at butt welds).

iv)

A statement of acceptance of data supplied by the Piping Stress section.

The piping stress section shall review the summary report in detail to establish the worst case loads and stresses acting at topsides data points and subsequently confirm that any changes do not compromise the requirements of section 2.2 of this procedure. The piping stress section shall finally update and re-issue to pipelines department and piping section the topsides stress isometric to reflect final load and stress data, clearly referencing the source. Any subsequent changes to the piping stress isometric shall be handled in accordance with section 4.5 of this procedure and re-issued as required to pipelines for further evaluation. All data supplied to piping stress section by pipelines section shall be placed in the relevant stress isometric file of the Stress Analysis Report. 5.0

DESIGN

5.1

Design Conditions The basis of design shall be taken to be the un-deformed and stress free state, with the exception of weight loads. Stresses and deformations due to transient and other conditions, such as those found during load out and transportation shall be treated as an additional design case, based on available data. Temperatures and pressures used in stress analysis shall normally be the design temperature and pressure as quoted in the Line List. Where this may lead to an

PROCEDURE FOR PIPING STRESS ANALYSIS 308-7080-ST-54-102 (OFFSHORE) Page 15 of 26 ____________________________________________________________________________ over-conservative design, the Process group shall be consulted and maximum operating conditions used. In such cases a note shall be added to the Line List regarding conditions used for stress analysis. The stress isometric shall be similarly annotated.

5.1.1 Temperature Selection of temperature range for thermal analysis is dependent upon the type of plant under consideration. (i)

On-shore Plant Where thermal displacement of the supporting structure can be considered negligible, the base temperature for thermal analysis shall be the installation temperature.

(ii)

Offshore Plant The steel deck of an offshore structure will respond to thermal changes. It may normally be assumed that structure and pipe temperatures will be equal during construction, and the pipe will therefore not be thermally stressed, unless some operating condition prevails. In this case, the base temperature for thermal analysis shall be the ambient temperature.

(iii)

Both installation (on-shore) and ambient temperature (offshore) are normally given as a range in the Design Premise document.

(iv)

The net algebraic difference between the installation or ambient temperature and the 'design' temperature (whichever produces the greatest temperature range) shall be used in thermal stress analysis for piping reactions. To properly evaluate the net stress range, the algebraic difference between any minimum and maximum temperature shall be applied.

(v)

In selection of 'design' temperature, consideration shall be given to specific system requirements outlined in section 4.7. The Process department shall be consulted regarding upset or excursion temperatures.

PROCEDURE FOR PIPING STRESS ANALYSIS 308-7080-ST-54-102 (OFFSHORE) Page 16 of 26 ____________________________________________________________________________

5.1.2

Pressure Where high stress at an elbow is encountered the difference between design and operating pressures shall be considered, since an increase pressure tends to decrease the stress intensification factor applied. It may be necessary to run calculations for both conditions to ensure safety. Process conditions which may result in impulse loadings such as pressure surge or slugging shall be identified by the Process Department and considered in the design. The Lead Stress Engineer shall notify the process group that this information is required on the P & ID.

5.1.3 Vibration (i)

The effects of vibration in piping systems shall be investigated where appropriate.

(ii)

Consideration shall be given to vibration directly or indirectly imposed upon piping by mechanical equipment.

(iii)

The possibility of vibration from the flowing fluid shall be assessed, with particular emphasis applied to valves in continuous flow gas service where a large pressure drop occurs, such as blow-down valves, anti-surge valves and JouleThompson process valves. Large pressure drop liquid services such as sea water dump lines shall be similarly investigated. Shock due to 'water' hammer shall be considered.

(iv)

If significant vibration is probable, the possibility of fatigue in the main piping and components, and in particular, small bore connections such as instruments, vents and drains shall be assessed. The design shall be modified if required, to prevent any possibility of damage.

(v)

Additional restraints, hold-down supports or shock arrestors shall be considered in order to moderate vibration. Small bore branch connections such as instruments, vents and drains may require

PROCEDURE FOR PIPING STRESS ANALYSIS 308-7080-ST-54-102 (OFFSHORE) Page 17 of 26 ____________________________________________________________________________ bracing to the header, or re-routing in order to restrain the mass. Refer to section 5.8, high strength steels. 5.2

Stress Limitations Stresses due to pressure, weight, thermal and imposed displacements, external and occasional loads, shall meet the requirements of the relevant code listed in section 3.

5.3

External Loads Where appropriate, environmental loads such as snow, ice and wind acting on exposed piping shall be evaluated using project environmental data, and appropriate National Codes. Solar radiation shall be considered in thermal analysis of exposed piping. In addition, the effects on piping systems of relative movements between platform modules, module/deck deflection, platform settlement and other imposed deflections shall be investigated where appropriate.

5.4

Loadings Applied to Mechanical Equipment Refer also to section 4.9. Loads applied by piping to pumps, compressors, vessels, exchangers, tanks and package units shall in general comply with the requirements of specification "Equipment Nozzle Loading Due to Piping reactions". Refer to document No. 308-7080-ST-54-005 for further information relating to analysis of piping connected to rotating compressors and large pumps. Results of analogue studies / mechanical response studies for positive displacement equipment shall be incorporated into the design with regard to loadings and pipe support locations.

5.5

Design and Analysis of Flanged Joints Pressure design of flanges shall generally be in accordance with Section 304.5 of ANSI B31.3.

PROCEDURE FOR PIPING STRESS ANALYSIS 308-7080-ST-54-102 (OFFSHORE) Page 18 of 26 ____________________________________________________________________________

When evaluating the effects of piping loads upon flanged joints the following shall be adopted. (i)

Axial force F (N) and resultant longitudinal moment M (Nmm) shall be expressed as an equivalent pressure Pe (Nmm-2) as in equation 1. Pe = 16 M + 4 F πG3 πG2

... equation 1

where G is the gasket reaction diameter (mm) (ii)

Design pressure P (Nmm-2) given by equation 2 shall be used to calculate flange and bolt stresses in accordance with ASME VIII Div. 1 Appendix 2. P = Pi + Pe

... equation 2

where Pi is the internal pressure. In the case of combined external and pressure loads, flange and bolt stresses shall be limited in accordance of the intent of Section 302.3 of ANSI B31.3. 5.6

Clamp Connectors Where clamp connectors are used in preference to flanged joints the Lead Stress Engineer shall liaise with the piping Materials group during the 'bid phase' to specify the piping loads that can be accommodated by clamp connectors, oversize hubs may be required.

5.7

External Loads Due to Blast Over pressure At an early stage in the project it shall be agreed with the Client whether blast over pressure effects are to be included in the piping design, or excluded.

PROCEDURE FOR PIPING STRESS ANALYSIS 308-7080-ST-54-102 (OFFSHORE) Page 19 of 26 ____________________________________________________________________________ If blast over pressure is included in the stress analysis scope of work, both the piping systems to be considered and the method of analysis shall be agreed with the Client and safety group. 5.8

Use of Fabricated Laterals in Process Piping Due to the high stress intensifications encountered and consequent risk of fatigue cracking in welds, fabricated lateral tees shall be avoided in process piping systems. Alternative use of standard forged or (integrally) reinforced 90° branch connections shall be discussed with the Process Department.

5.9

High Strength Stainless Steels Where high strength stainless steel such as duplex and super-duplex is used, precautions shall be taken to avoid the possibility of cracking in components due to vibration induced fatigue. This may require avoidance of integrally reinforced small bore branch connections on thin wall pipe, and use of stub-in or pad reinforced branches in preference. Unconnected small bore branches such as vents, drains and instrument connections may require cruciform bracing or other support back to the parent pipe.

5.10

Use of Mechanical Joints Bellows and other such mechanical devices used to limit forces and displacements due to pipe movement shall be avoided . The preferred means of absorbing displacements shall be by use of the inherent flexibility of the piping system. Prior to specification of bellows etc. in a piping system, the advice of the Corporate stress consultant and Client approval shall be obtained.

5.11

Transportation Loads Normal practice is to ensure that the modules are supported in the same place in the yard as offshore. Lead Stress Engineer shall liaise with the Structural group to ensure that this is implemented.

PROCEDURE FOR PIPING STRESS ANALYSIS 308-7080-ST-54-102 (OFFSHORE) Page 20 of 26 ____________________________________________________________________________ The deflected shape of the platform/module may change from the Fabrication yard (where pipework is initially installed) to the finally installed position i.e. offshore, resulting in additional imposed deflection of the pipework. Structural deflections during initial installation, transport, and finally installed conditions should be obtained from the structural department and incorporated into the stress analysis where relevant. Consideration shall also be given to inertia loadings and structural deflection arising from the transportation of the module/platform from the fabrication yard to the finally installed position.

PROCEDURE FOR PIPING STRESS ANALYSIS 308-7080-ST-54-102 (OFFSHORE) Page 21 of 26 ____________________________________________________________________________ 6.0

APPENDICES

ATTACHMENT 1 1.0

OVERVIEW OF CAESAR II CAESAR II is a finite element program based on the direct stiffness matrix solution method, specifically written for static and dynamic stress analysis of three dimensional piping systems. The program runs on PC using compiled Fortran files, which cannot be accessed or corrupted by the user. Authorised access for use of the program is controlled by a plug-in electronic security device (dongle). Calculations may be performed in accordance with several Design Codes. Full details of the program are available in the User Manual.

PROCEDURE FOR PIPING STRESS ANALYSIS 308-7080-ST-54-102 (OFFSHORE) Page 22 of 26 ____________________________________________________________________________ ATTACHMENT 2 REQUIREMENTS FOR STRESS ISOMETRICS 1.0

Stress isometrics shall be produced of critical lines as indicated by the stress engineer in the critical line list.

2.0

Drawing numbers shall be taken from the stress isometric index (ref. Critical Line List Procedures). The Stress Isometric Index is retained, updated and issued by the Lead Stress Engineer.

3.0

Where possible an entire system should be shown on a single drawing, refer to the stress section to agree convenient system breaks if more than one drawing is required.

4.0

Each stress isometric should contain the following information where applicable: System title, drawing number and revision ii) Line numbers, sizes and maximum or minimum design conditions iii) Insulation thickness if any iv) Valve and component weights v) All penetrations through decks, walls, firewalls etc. vi) Equipment numbers and nozzle numbers vii) Equipment and vessel fixed points viii) Continuation drawing references ix) Reference dimensions to appropriate grid lines x) Footnotes if any xi) North arrow xii) At least one elevation xiii) All specification changes, and limits of insulation.

5.0

Unless specifically required otherwise, branch connections below 2" nb need not be detailed. Such branch locations however must be clearly marked and dimensioned on the header.

6.0

Platform North shall be the negative "x" direction or "top left".

7.0

The "by", "checked " and date boxes shall be completed in all cases.

PROCEDURE FOR PIPING STRESS ANALYSIS 308-7080-ST-54-102 (OFFSHORE) Page 23 of 26 ____________________________________________________________________________

ATTACHMENT 3

TYPICAL STRESS ISOMETRIC

REFER TO STRESS SECTION

PROCEDURE FOR PIPING STRESS ANALYSIS 308-7080-ST-54-102 (OFFSHORE) Page 24 of 26 ____________________________________________________________________________

PROCEDURE FOR PIPING STRESS ANALYSIS 308-7080-ST-54-102 (OFFSHORE) Page 25 of 26 ____________________________________________________________________________

REVISION

NO

YES

FOR RESTRAINT, SUPPORT DATA, LOADS & DISPL’S

SUPPORTS SUBSEA

STRESS FOR FILES & ARCHIVE

IF NOZZLE LOADS ARE NONSTANDARD

COMPILE STRESS ANALYSIS REPORTS INCORPORATING REFERENCE DATA, ISOMETRICS, CALCULATIONS AND NOTES

AT END OF PROJECT

YES

ADD NODES, RESTRAINTS, NOTES & DESIGN DATA TO STRESS ISO’ ORIGINAL

NO

RESULTS ACCEPTABLE ?

MECHANICAL

STORE ALL DATA & CAL’S IN STRESS ISO’ FILE, UPDATE ‘CLL’ & ST’SS ISO’ INDEX

REVISE RESTRAINTS OR MODIFY ROUTING (REFER TO SUPPTS & PIPING GROUPS)

RUN COMPUTER BASED STRESS CALC’ AS REQUIRED

FOR INTERFACE & INFORMATION

APPROVE STRESS ISO’ & ISSUE VIA LEAD STRESS ENG’R

COMPLETE HAND CALCULATIONS AS REQUIRED

DO PRELIM’ CALC’S ADD OR UPDATE RESTRAINT DATA etc. ON ST’SS ISO’ WORKING COPY

LEAD STRESS ENGINEER TO ANNOTATE ORIGINAL STRESS ISOMETRIC

FOR CONFIRMATION OF PIPE ROUTING, ETC.

PIPING

PRIOR TO ISSUE, REVIEW ALL SUPPORT DESIGNS FOR CRITICAL LINES

1 x PRINT TO STRESS SECTION (WORKING COPY)

NO

IS A FORMAL COMPUTER CALCUATION REQUIRED

PIPING STRESS ANALYSIS - HANDLING OF ISOMETRICS & DATA

START HERE

NEW PIPING ISOMETRIC OR REVISION TO EXISTING ?

NEW

PIPING MARK-UP CHANGES ON MASTER PIPING DOCUMENT, INFORM LEAD STRESS ENGINEER

STRESS DOES REVISION REQUIRE UPDATE TO ORIGINAL STRESS ISOMETRIC

YES

PIPING DRAW OR UPDATE ORIGINAL STRESS ISOMETRIC

1 x PRINT

SUPPORTS ADD WEIGHT SUPPORT LOCATIONS TO ISOMETRIC PRINT

PROCEDURE FOR PIPING STRESS ANALYSIS 308-7080-ST-54-102 (OFFSHORE) Page 26 of 26 ____________________________________________________________________________

ATTACHMENT 5 FLOWCHART FOR STRESS ANALYSIS