5 api 579 compatibility mode

The API 579 Fitness-for-ServiceStandard – The Current State ofTechnology and a Ten Year Look

Ahead

Robert Brown, P.E.

10th Annual IPEIA (formerly NPEC) ConferenceBanff Centre in Banff Alberta, Canada

February 1 – 3, 2006

Presentation Outline

• Introduction• API 579 Development Background• Overview of API 579• New Joint API and ASME FFS Standard• Planned Developments for API/ASME 579• Overview of API/ASME 579-2006• Future Enhancements Following the 2006 Publication of

API/ASME 579• Technical Basis and Validation of API/ASME 579 FFS

Assessment Methods• Understanding of Damage Mechanisms• In-Service Inspection Codes and Fitness-For-Service• Fitness-For-Service and RBI - Complementary Technologies• Harmonizing Pressure Vessel Design and Fitness-For-Service• Summary

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• Introduction• API 579 Development Background• Overview of API 579• New Joint API and ASME FFS Standard• Planned Developments for API/ASME 579• Overview of API/ASME 579-2006• Future Enhancements Following the 2006 Publication of

API/ASME 579• Technical Basis and Validation of API/ASME 579 FFS

Assessment Methods• Understanding of Damage Mechanisms• In-Service Inspection Codes and Fitness-For-Service• Fitness-For-Service and RBI - Complementary Technologies• Harmonizing Pressure Vessel Design and Fitness-For-Service• Summary

Introduction

• The ASME and API construction codes do not providerules to evaluate a component containing a flaw ordamage that results from operation after initialcommissioning

• Fitness-For-Service (FFS) assessments are quantitativeengineering evaluations that are performed todemonstrate the structural integrity of an in-servicecomponent containing a flaw or damage

• API 579 was developed to evaluate flaws and damageassociated with in-service operation

• API 579 assessment procedures were not originallyintended to evaluate fabrication flaws; however, theseprocedures have been used for this purpose by manyOwner-Users

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• The ASME and API construction codes do not providerules to evaluate a component containing a flaw ordamage that results from operation after initialcommissioning

• Fitness-For-Service (FFS) assessments are quantitativeengineering evaluations that are performed todemonstrate the structural integrity of an in-servicecomponent containing a flaw or damage

• API 579 was developed to evaluate flaws and damageassociated with in-service operation

• API 579 assessment procedures were not originallyintended to evaluate fabrication flaws; however, theseprocedures have been used for this purpose by manyOwner-Users

Introduction

• If the damage mechanism cannot be identified, then aFFS assessment should not be performed per API 579

– Identification of damage mechanism is the keycomponent in the FFS assessment

– Firm understanding of the damage mechanism isrequired to evaluate the time-dependence of the damage

– Time-dependence of damage is required to develop aremaining life and inspection plan

• API 579 provides guidance for conducting FFSassessments using methods specifically prepared forequipment in the refining and petrochemical industry;however, this document is currently being used inother industries such as the fossil utility, pulp & paper,food processing, and non-commercial nuclear

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• If the damage mechanism cannot be identified, then aFFS assessment should not be performed per API 579

– Identification of damage mechanism is the keycomponent in the FFS assessment

– Firm understanding of the damage mechanism isrequired to evaluate the time-dependence of the damage

– Time-dependence of damage is required to develop aremaining life and inspection plan

• API 579 provides guidance for conducting FFSassessments using methods specifically prepared forequipment in the refining and petrochemical industry;however, this document is currently being used inother industries such as the fossil utility, pulp & paper,food processing, and non-commercial nuclear

API 579 Development BackgroundAPI’s Definition of Fitness-For-Service

• An FFS assessment is a multi-disciplinary engineeringanalysis of equipment to determine whether it is fit forcontinued service, typically until the next shutdown

• The equipment may contain flaws, not met currentdesign standards, or be subjected to more severeoperating conditions than current design

• The product of a FFS assessment is a decision to run asis, monitor, alter, repair, or replace; guidance on aninspection interval is also provided

• FFS assessments consist of analytical methods (mainlystress analysis) to assess flaws and damage

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• An FFS assessment is a multi-disciplinary engineeringanalysis of equipment to determine whether it is fit forcontinued service, typically until the next shutdown

• The equipment may contain flaws, not met currentdesign standards, or be subjected to more severeoperating conditions than current design

• The product of a FFS assessment is a decision to run asis, monitor, alter, repair, or replace; guidance on aninspection interval is also provided

• FFS assessments consist of analytical methods (mainlystress analysis) to assess flaws and damage

API 579 Development BackgroundNeed for FFS Standardization

• Plant safety and Compliance with US OSHA 1910Process Safety Management (PSM) Legislation

• Operation of aging facilities

• Maintaining safe, reliable operations with an increase inrun-lengths, increase in severity of operations and/ordecrease in shut-down periods

• Rationalizing flaws found by more rigorous in-serviceinspections than those conducted during originalconstruction

• Refining and petrochemical industry is unique due tothe wide variety of processes and operating conditions,materials of construction, and damage mechanisms

• Standardization facilitates acceptance by jurisdictions

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• Plant safety and Compliance with US OSHA 1910Process Safety Management (PSM) Legislation

• Operation of aging facilities

• Maintaining safe, reliable operations with an increase inrun-lengths, increase in severity of operations and/ordecrease in shut-down periods

• Rationalizing flaws found by more rigorous in-serviceinspections than those conducted during originalconstruction

• Refining and petrochemical industry is unique due tothe wide variety of processes and operating conditions,materials of construction, and damage mechanisms

• Standardization facilitates acceptance by jurisdictions

API 579 Development BackgroundMPC FFS JIP Program Overview

• Joint Industry Project (JIP) started in 1990 under TheMaterials Properties Council (MPC)

• Technology development focus

• Base resource document and computer softwaredeveloped

• Information disseminated to public through technicalpublications and symposia

• Technology developed provides basis for API 579

• Continued sponsorship by owner-users and fundingsupport from API indicates high level of interest in FFS

• MPC FFS JIP continues to develop new FFS technologythat is subsequently incorporated into API 579

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• Joint Industry Project (JIP) started in 1990 under TheMaterials Properties Council (MPC)

• Technology development focus

• Base resource document and computer softwaredeveloped

• Information disseminated to public through technicalpublications and symposia

• Technology developed provides basis for API 579

• Continued sponsorship by owner-users and fundingsupport from API indicates high level of interest in FFS

• MPC FFS JIP continues to develop new FFS technologythat is subsequently incorporated into API 579

Overview of API 579General

• Applicable to pressurized components in pressurevessels, piping, and tankage (principles can also beapplied to rotating equipment)

• Highly structured document with a modularorganization based on flaw type/damage condition tofacilitate use and updates

• Multi-level assessment - higher levels are lessconservative but require more detailed analysis/data

– Level 1 - Inspector/Plant Engineer

– Level 2 - Plant Engineer

– Level 3 - Expert Engineer

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• Applicable to pressurized components in pressurevessels, piping, and tankage (principles can also beapplied to rotating equipment)

• Highly structured document with a modularorganization based on flaw type/damage condition tofacilitate use and updates

• Multi-level assessment - higher levels are lessconservative but require more detailed analysis/data

– Level 1 - Inspector/Plant Engineer

– Level 2 - Plant Engineer

– Level 3 - Expert Engineer


• Identifies data requirements, applicability andlimitations of assessment procedures, and acceptancecriteria

• Contains flow charts, figures, and example problems tosimplify use of the assessment procedures

• Provides recommendations for in-service monitoringand/or remediation for difficult situations

• Provides recommendations for stress analysistechniques, NDE, and sources for materials properties

• Requires a remaining life to be evaluated; remaininglife is the basis for the inspection interval

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• Identifies data requirements, applicability andlimitations of assessment procedures, and acceptancecriteria

• Contains flow charts, figures, and example problems tosimplify use of the assessment procedures

• Provides recommendations for in-service monitoringand/or remediation for difficult situations

• Provides recommendations for stress analysistechniques, NDE, and sources for materials properties

• Requires a remaining life to be evaluated; remaininglife is the basis for the inspection interval


• General FFS assessment procedure used in API 579 forall flaw types is provided in Section 2 that includes thefollowing steps:– Step 1 - Flaw & damage mechanism identification– Step 2 - Applicability & limitations of FFS procedures– Step 3 - Data requirements– Step 4 - Assessment techniques & acceptance criteria– Step 5 - Remaining life evaluation– Step 6 - Remediation– Step 7 - In-service monitoring– Step 8 - Documentation

• Some of the steps shown above may not be necessarydepending on the application and damage mechanism

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• General FFS assessment procedure used in API 579 forall flaw types is provided in Section 2 that includes thefollowing steps:– Step 1 - Flaw & damage mechanism identification– Step 2 - Applicability & limitations of FFS procedures– Step 3 - Data requirements– Step 4 - Assessment techniques & acceptance criteria– Step 5 - Remaining life evaluation– Step 6 - Remediation– Step 7 - In-service monitoring– Step 8 - Documentation

• Some of the steps shown above may not be necessarydepending on the application and damage mechanism

Overview of API 579Contents

• API 579 originally released in 2000: Nine flaws anddamage conditions are covered with supportingappendices

• Organized to facilitate use and updates– Section covering overall assessment procedure

– Separate sections for each flaw type/condition

– Consistent organization within each section

– Information common to more than one section placed inappendices

• Self-contained document - do not need to purchaseother API standards to perform an assessment

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• API 579 originally released in 2000: Nine flaws anddamage conditions are covered with supportingappendices

• Organized to facilitate use and updates– Section covering overall assessment procedure

– Separate sections for each flaw type/condition

– Consistent organization within each section

– Information common to more than one section placed inappendices

• Self-contained document - do not need to purchaseother API standards to perform an assessment


Main Sections• Section 1 - Introduction

• Section 2 - FFS Engineering Evaluation Procedure

• Section 3 - Assessment of Equipment for Brittle Fracture

• Section 4 - Assessment of General Metal Loss (tm < tmin - large area)

• Section 5 - Assessment of Localized Metal Loss (tm < tmin - small area)

• Section 6 - Assessment of Pitting Corrosion

• Section 7 - Assessment of Blisters and Laminations

• Section 8 - Assessment of Weld Misalignment and Shell Distortions

• Section 9 - Assessment of Crack-Like Flaws

• Section 10 - Assessment of Equipment Operating in the Creep Regime(Draft version)

• Section 11 - Assessment of Fire Damage

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Main Sections• Section 1 - Introduction

• Section 2 - FFS Engineering Evaluation Procedure

• Section 3 - Assessment of Equipment for Brittle Fracture

• Section 4 - Assessment of General Metal Loss (tm < tmin - large area)

• Section 5 - Assessment of Localized Metal Loss (tm < tmin - small area)

• Section 6 - Assessment of Pitting Corrosion

• Section 7 - Assessment of Blisters and Laminations

• Section 8 - Assessment of Weld Misalignment and Shell Distortions

• Section 9 - Assessment of Crack-Like Flaws

• Section 10 - Assessment of Equipment Operating in the Creep Regime(Draft version)

• Section 11 - Assessment of Fire Damage


Appendices• Appendix A - Thickness, MAWP, and Stress Equations for a FFS

Assessment

• Appendix B - Stress Analysis Overview for a FFS Assessment

• Appendix C - Compendium of Stress Intensity Factor Solutions

• Appendix D - Compendium of Reference Stress Solutions

• Appendix E - Residual Stresses in a FFS Evaluation

• Appendix F - Material Properties for a FFS Assessment

• Appendix G - Deterioration and Failure Modes

• Appendix H - Validation

• Appendix I - Glossary of Terms and Definitions

• Appendix J - Technical Inquires

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Appendices• Appendix A - Thickness, MAWP, and Stress Equations for a FFS

Assessment

• Appendix B - Stress Analysis Overview for a FFS Assessment

• Appendix C - Compendium of Stress Intensity Factor Solutions

• Appendix D - Compendium of Reference Stress Solutions

• Appendix E - Residual Stresses in a FFS Evaluation

• Appendix F - Material Properties for a FFS Assessment

• Appendix G - Deterioration and Failure Modes

• Appendix H - Validation

• Appendix I - Glossary of Terms and Definitions

• Appendix J - Technical Inquires

Overview of API 579Relationships to Other FFS Standards

• The API Committee on Refinery Equipment (CRE) Task Groupresponsible for development of API 579 reviewed internalcorporate methods, international standards and publications,and incorporated appropriate technology

• In most cases, modifications to existing or development ofnew FFS methods were required

• API Level 3 Assessments permit use of alternative FFSprocedures. For example, Section 9 covering crack-like flawsprovides reference to British Energy R-6, BS-7910, EPRI J-integral, and other published methods

• The API Task Group is working to set up technical liaisons withother international FFS standard writing bodies (e.g. FITNET)

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• The API Committee on Refinery Equipment (CRE) Task Groupresponsible for development of API 579 reviewed internalcorporate methods, international standards and publications,and incorporated appropriate technology

• In most cases, modifications to existing or development ofnew FFS methods were required

• API Level 3 Assessments permit use of alternative FFSprocedures. For example, Section 9 covering crack-like flawsprovides reference to British Energy R-6, BS-7910, EPRI J-integral, and other published methods

• The API Task Group is working to set up technical liaisons withother international FFS standard writing bodies (e.g. FITNET)

New Joint API and ASME FFS Standard

• API and ASME have agreed to form a joint committeeto produce a single FFS Standard that can be used forpressure-containing equipment

• API 579 will form the basis of the new co-brandedAPI/ASME standard that will be produced by thiscommittee

• The initial release of the new co-branded standarddesignated as API/ASME 579 will occur in June, 2006

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• API and ASME have agreed to form a joint committeeto produce a single FFS Standard that can be used forpressure-containing equipment

• API 579 will form the basis of the new co-brandedAPI/ASME standard that will be produced by thiscommittee

• The initial release of the new co-branded standarddesignated as API/ASME 579 will occur in June, 2006

• The second edition of API 579 and the new API/ASMEjoint standard will include all topics currently containedin API 579 and will also include new parts covering FFSassessment procedures that address unique damagemechanisms experienced by other industries

• The agreement to produce a joint standard on FFStechnology is a landmark decision that will permit thefocusing of resources in the US to develop a singledocument that can be used by all industries

• In addition, a joint FFS standard will help avoidjurisdictional conflicts and promote uniform acceptanceof FFS technology

New Joint API and ASME FFS Standard

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• The second edition of API 579 and the new API/ASMEjoint standard will include all topics currently containedin API 579 and will also include new parts covering FFSassessment procedures that address unique damagemechanisms experienced by other industries

• The agreement to produce a joint standard on FFStechnology is a landmark decision that will permit thefocusing of resources in the US to develop a singledocument that can be used by all industries

• In addition, a joint FFS standard will help avoidjurisdictional conflicts and promote uniform acceptanceof FFS technology

New Developments for API/ASME 579

• To avoid confusion with other ASME B&PV Codes andStandards, Sections in API 579 are being renamed toParts

• New Enhancements – Existing Sections and New Parts– Part 5 – Assessment of Local Thin Areas, assessment procedures

for gouges being relocated to Part 12– Part 7 – Assessment of Blisters and HIC/SOHIC Damage,

assessment procedures for HIC/SOHIC damage have been added– Part 8 – Assessment of Weld Misalignment and Bulges,

assessment procedures for bulges being modified (in progress),assessment procedures for dents being relocated to Part 12

– Part 10 – Assessment of Equipment Operating in the Creep Range,assessment procedures for remaining life calculations forcomponents with or without crack-like flaws are provided

– Part 12 – Assessment of Dents, Gouges, and Dent-GougeCombinations, new Part

– Part 13 – Assessment of Laminations, new Part

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• To avoid confusion with other ASME B&PV Codes andStandards, Sections in API 579 are being renamed toParts

• New Enhancements – Existing Sections and New Parts– Part 5 – Assessment of Local Thin Areas, assessment procedures

for gouges being relocated to Part 12– Part 7 – Assessment of Blisters and HIC/SOHIC Damage,

assessment procedures for HIC/SOHIC damage have been added– Part 8 – Assessment of Weld Misalignment and Bulges,

assessment procedures for bulges being modified (in progress),assessment procedures for dents being relocated to Part 12

– Part 10 – Assessment of Equipment Operating in the Creep Range,assessment procedures for remaining life calculations forcomponents with or without crack-like flaws are provided

– Part 12 – Assessment of Dents, Gouges, and Dent-GougeCombinations, new Part

– Part 13 – Assessment of Laminations, new Part

• New Enhancements – Existing and New Appendices– Appendix B – Stress Analysis Overview for a FFS Assessment,

complete rewrite to incorporate new elastic-plastic analysismethods and fatigue evaluation technology developed for theASME Div 2 Re-write Project

– Appendix C – Compendium of Stress Intensity Factor Solutions,new stress intensity factor solutions for thick wall cylinders,through wall cracks in cylinders and spheres, holes in plates

– Appendix E - Compendium of Residual Stress Solutions, completerewrite to incorporate new solutions developed by PVRC JointIndustry Project

– Appendix F – Material Properties for a FFS Assessment, newfracture toughness estimation methods and stress-strain curvemodel incorporated

– Appendix H – Technical Basis and Validation of FFS Procedures

– Appendix K – Crack Opening Areas, new appendix covering crackopening areas for through-wall flaws in cylinders and spheres


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• New Enhancements – Existing and New Appendices– Appendix B – Stress Analysis Overview for a FFS Assessment,

complete rewrite to incorporate new elastic-plastic analysismethods and fatigue evaluation technology developed for theASME Div 2 Re-write Project

– Appendix C – Compendium of Stress Intensity Factor Solutions,new stress intensity factor solutions for thick wall cylinders,through wall cracks in cylinders and spheres, holes in plates

– Appendix E - Compendium of Residual Stress Solutions, completerewrite to incorporate new solutions developed by PVRC JointIndustry Project

– Appendix F – Material Properties for a FFS Assessment, newfracture toughness estimation methods and stress-strain curvemodel incorporated

– Appendix H – Technical Basis and Validation of FFS Procedures

– Appendix K – Crack Opening Areas, new appendix covering crackopening areas for through-wall flaws in cylinders and spheres

• New Enhancements – Example Problems

– All example problems will be removed and placed in aseparate example problems manual

– Additional example problems with more backgroundinformation will be provided

• Future Enhancements (after 2006) - New Parts

– Assessment of Hot-Spots

– Assessment of HTHA (High Temperature Hydrogen Attack)Damage

– Assessment of Fatigue Damage


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• New Enhancements – Example Problems

– All example problems will be removed and placed in aseparate example problems manual

– Additional example problems with more backgroundinformation will be provided

• Future Enhancements (after 2006) - New Parts

– Assessment of Hot-Spots

– Assessment of HTHA (High Temperature Hydrogen Attack)Damage

– Assessment of Fatigue Damage

Overview of API/ASME 579-2006

• Part 3: Brittle Fracture– Provides guidelines for evaluating the resistance to brittle

fracture of existing carbon and low alloy steel pressurevessels, piping, and storage tanks+ Screening of equipment for susceptibility (Level 1 & 2)+ Detailed assessment using fracture mechanics (Level 3 per

Part 9)+ Assessment typically performed on a weld-joint by weld joint

basis

– The purpose of this assessment is to avoid a catastrophicbrittle fracture failure consistent with ASME Code,Section VIII design philosophy; however, it does notensure against service-induced cracks resulting inleakage or arrest of a running brittle fracture

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• Part 3: Brittle Fracture– Provides guidelines for evaluating the resistance to brittle

fracture of existing carbon and low alloy steel pressurevessels, piping, and storage tanks+ Screening of equipment for susceptibility (Level 1 & 2)+ Detailed assessment using fracture mechanics (Level 3 per

Part 9)+ Assessment typically performed on a weld-joint by weld joint

basis

– The purpose of this assessment is to avoid a catastrophicbrittle fracture failure consistent with ASME Code,Section VIII design philosophy; however, it does notensure against service-induced cracks resulting inleakage or arrest of a running brittle fracture

• Part 3: Brittle Fracture -Changes– Minimal changes to existing

API 579 methodology inSection 3; Changes instructure to improve userfriendliness

– Minimum AllowableTemperature (MAT) -Singletemperature or envelope oftemperature as function ofpressure

– Critical ExposureTemperature (CET) -Lowestmetal temperature atprimary stress > 8 ksi


21

• Part 3: Brittle Fracture -Changes– Minimal changes to existing

API 579 methodology inSection 3; Changes instructure to improve userfriendliness

– Minimum AllowableTemperature (MAT) -Singletemperature or envelope oftemperature as function ofpressure

– Critical ExposureTemperature (CET) -Lowestmetal temperature atprimary stress > 8 ksi


• Part 4: General Metal Loss

– Covers FFS for pressurized components subject togeneral metal loss resulting from corrosion and/orerosion+ Procedures can be applied to both uniform and local metal

loss+ Procedures provide an MAWP or MAT

– Assessment procedures in this section are based on athickness averaging approach+ Suitable result is obtained when applied to uniform metal

loss+ For local or non-uniform metal loss, the Part 4 thickness

averaging approach may produce overly conservativeresults; the assessment procedures of Part 5 (FFS rulescovering local metal loss) can be utilized to reduce theconservatism in the analysis

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• Part 4: General Metal Loss

– Covers FFS for pressurized components subject togeneral metal loss resulting from corrosion and/orerosion+ Procedures can be applied to both uniform and local metal

loss+ Procedures provide an MAWP or MAT

– Assessment procedures in this section are based on athickness averaging approach+ Suitable result is obtained when applied to uniform metal

loss+ For local or non-uniform metal loss, the Part 4 thickness

averaging approach may produce overly conservativeresults; the assessment procedures of Part 5 (FFS rulescovering local metal loss) can be utilized to reduce theconservatism in the analysis


• Part 4: General Metal Loss - Changes– Minimal changes to existing API 579 methodology– Change from tmin to trd

Existing

23

New

Existing


• Part 5: Local Metal Loss– The assessment procedures of Part 5 are for the analysis

of local metal loss or Local Thin Areas (LTA)– The procedures of Part 4 are for general (uniform and

non-uniform) metal loss

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• Part 5: Local Metal Loss– The assessment procedures of Part 5 are for the analysis

of local metal loss or Local Thin Areas (LTA)– The procedures of Part 4 are for general (uniform and

non-uniform) metal loss


• Part 5: Local Metal Loss - Changes

– Level 1 Assessment

+ Longitudinal plane - screening curve changed to family ofcurves f(RSFa, E); groundwork for adapting to differentCodes

+ Circumferential plane - screening curve changed to family ofcurves f(RSFa, E); Includes 20% of allowable as bendingstress; more conservative


+ Longitudinal plane - New Folias factor; no limitation onlength of LTA (was lambda<5)

+ Circumferential plane - Added “circumferential” Folias factorto analysis; changed acceptability criteria from yield basis toallowable stress basis

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• Part 5: Local Metal Loss - Changes


+ Longitudinal plane - screening curve changed to family ofcurves f(RSFa, E); groundwork for adapting to differentCodes

+ Circumferential plane - screening curve changed to family ofcurves f(RSFa, E); Includes 20% of allowable as bendingstress; more conservative


+ Longitudinal plane - New Folias factor; no limitation onlength of LTA (was lambda<5)

+ Circumferential plane - Added “circumferential” Folias factorto analysis; changed acceptability criteria from yield basis toallowable stress basis


• Part 5: Local MetalLoss - Changes– New Level 2 Assessment

procedure is providedfor evaluating cylindricalshells with LTAs subjectto external pressure

– New method based onidealized cylindrical shell

– Basic equation is:

L1 L2 L3 L4

LT

t1 t2 t3 t4

Actual Cylindrical Shell

Idealized Cylindrical Shell

Stiffening Rings

26

• Part 5: Local MetalLoss - Changes– New Level 2 Assessment

procedure is providedfor evaluating cylindricalshells with LTAs subjectto external pressure

– New method based onidealized cylindrical shell

– Basic equation is:

L1 L2 L3 L4

LT

t1 t2 t3 t4

Actual Cylindrical Shell

Idealized Cylindrical Shell

Stiffening Rings

1

1

n

ii

r nie

i i

LMAWP

LP


• Part 6: Pitting

– The assessment procedures in Part 6 were developed toevaluate metal loss from pitting corrosion

– Pitting is defined as localized regions of metal loss whichcan be characterized by a pit diameter on the order ofthe plate thickness or less, and a pit depth that is lessthan the plate thickness

– Assessment procedures are provided to evaluate bothwidespread and localized pitting in a component with orwithout a region of metal loss

– The procedures can be used to assess a damaged arrayof blisters as described in Part 7

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• Part 6: Pitting

– The assessment procedures in Part 6 were developed toevaluate metal loss from pitting corrosion

– Pitting is defined as localized regions of metal loss whichcan be characterized by a pit diameter on the order ofthe plate thickness or less, and a pit depth that is lessthan the plate thickness

– Assessment procedures are provided to evaluate bothwidespread and localized pitting in a component with orwithout a region of metal loss

– The procedures can be used to assess a damaged arrayof blisters as described in Part 7


• Part 6: Pitting - Changes

– Level 1 Screening+ Pitting Charts

* Visual FFS Assessment (similar to ASME Code porosity charts),* Current Level 1 and existing Level 2 merged into new Level 2

+ Data for Assessment* Include a photograph with reference scale and/or rubbing of the

surface* Maximum pit depth* Cross section of UT thickness scan can also be used

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– Level 1 Screening+ Pitting Charts

* Visual FFS Assessment (similar to ASME Code porosity charts),* Current Level 1 and existing Level 2 merged into new Level 2

+ Data for Assessment* Include a photograph with reference scale and/or rubbing of the

surface* Maximum pit depth* Cross section of UT thickness scan can also be used


• Part 6: Pitting -Changes– Pitting Charts

+ FFS by visuallycomparing pit chartto actual damage plusestimate of maximumpit depth

+ Pit charts provided fora different pittingdamages measuredas a percentage ofthe affected area in a6 inch by 6 inch

+ RSF provided for eachpit density and fourw/t ratios (0.2, 0.4,0.6, 0.8)

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• Part 6: Pitting -Changes– Pitting Charts

+ FFS by visuallycomparing pit chartto actual damage plusestimate of maximumpit depth

+ Pit charts provided fora different pittingdamages measuredas a percentage ofthe affected area in a6 inch by 6 inch

+ RSF provided for eachpit density and fourw/t ratios (0.2, 0.4,0.6, 0.8)

Pitting Chart – API 579 Grade 4 Pitting



– Level 1 Screening+ Determine ratio of remaining wall thickness to the future

wall thickness in pitted region:+ Find pitting chart that matches damage and determine RSF

,

max

rd maxwt

c

rd

max

c

t wR

t

wheret thickness away from pitted region

w pit depth

t future corroded thickness

30

,

max

rd maxwt

c

rd

max

c

t wR

t

wheret thickness away from pitted region

w pit depth

t future corroded thickness


• Part 7: Hydrogen Blisters and HIC/SOHIC (New)

– Provides assessment procedures for low strength ferriticsteel pressurized components with hydrogen inducedcracking (HIC) and blisters, and stress oriented HIC(SOHIC) damage

– Excludes:+ Sulfide stress cracking (SSC)+ Hydrogen embrittlement of high strength steels (Brinnell

>232)+ Excludes methane blistering+ HTHA

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– Provides assessment procedures for low strength ferriticsteel pressurized components with hydrogen inducedcracking (HIC) and blisters, and stress oriented HIC(SOHIC) damage

– Excludes:+ Sulfide stress cracking (SSC)+ Hydrogen embrittlement of high strength steels (Brinnell

>232)+ Excludes methane blistering+ HTHA


• Part 7: Hydrogen Blisters and HIC/SOHIC (New)– Various forms of damage all related to hydrogen being

charged into the steel from a surface corrosion reactionin an aqueous H2S containing environment.

– Hydrogen Blistering+ Hydrogen blisters form bulges on the ID, the OD or within

the wall thickness of a pipe or pressure vessel.+ Atomic H collects at a discontinuity (inclusion or lamination)

in the steel+ H atoms form molecular hydrogen which is too large to

diffuse out; pressure builds to excess of YS and localdeformation occurs, forming a blister

– Hydrogen Induced Cracking (HIC)+ Hydrogen blisters can form at different depths from the

surface. And may develop cracks that link them together.+ Interconnecting cracks between the blisters often are

referred to as “stepwise cracking”

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• Part 7: Hydrogen Blisters and HIC/SOHIC (New)– Various forms of damage all related to hydrogen being

charged into the steel from a surface corrosion reactionin an aqueous H2S containing environment.

– Hydrogen Blistering+ Hydrogen blisters form bulges on the ID, the OD or within

the wall thickness of a pipe or pressure vessel.+ Atomic H collects at a discontinuity (inclusion or lamination)

in the steel+ H atoms form molecular hydrogen which is too large to

diffuse out; pressure builds to excess of YS and localdeformation occurs, forming a blister

– Hydrogen Induced Cracking (HIC)+ Hydrogen blisters can form at different depths from the

surface. And may develop cracks that link them together.+ Interconnecting cracks between the blisters often are

referred to as “stepwise cracking”

• Part 7: Hydrogen Blisters and HIC/SOHIC (New)– Stress Oriented Hydrogen Induced Cracking (SOHIC)

+ Similar to HIC, but more damaging+ Arrays of cracks stacked on top of each other, resulting in

through-thickness crack+ Seen mostly in HAZ, due to residual stresses


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Zero degreescan overlaidwith 45 degreeshearwaveresults(provided byWestechInspection, Inc.)


– Level 2 HIC Assessment


Strength check -Determine RSF byconsidering regionas LTA withreduced strength(20%)

Fracture check -Evaluate HIC as acrack-like flaw perPart 9

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Strength check -Determine RSF byconsidering regionas LTA withreduced strength(20%)

Fracture check -Evaluate HIC as acrack-like flaw perPart 9


• Part 8: Weld misalignment And Shell Distortions– The procedures in this part can be used to assess weld

misalignments and shell distortions in components madeup of flat plates; cylindrical, conical, and spherical shells;and formed heads.

– Weld Misalignment – centerline offset, angularmisalignment (peaking), and a combination of centerlineoffset and angular misalignment

– Shell Distortion – Categories include:+ General Shell Distortion+ Out-of-roundness+ Bulge

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• Part 8: Weld misalignment And Shell Distortions– The procedures in this part can be used to assess weld

misalignments and shell distortions in components madeup of flat plates; cylindrical, conical, and spherical shells;and formed heads.

– Weld Misalignment – centerline offset, angularmisalignment (peaking), and a combination of centerlineoffset and angular misalignment

– Shell Distortion – Categories include:+ General Shell Distortion+ Out-of-roundness+ Bulge


• Part 8: Weld misalignment And Shell Distortions -Changes– Pseudo code provided for computation of Fourier Series

coefficients for analysis of out-of-roundness radius data– Assessment procedure rules for bulges deleted, new rules

currently being developed by MPC FFS JIP, will not beincluded in the 2006 edition

36

• Part 8: Weld misalignment And Shell Distortions -Changes– Pseudo code provided for computation of Fourier Series

coefficients for analysis of out-of-roundness radius data– Assessment procedure rules for bulges deleted, new rules

currently being developed by MPC FFS JIP, will not beincluded in the 2006 edition


• Part 9: Crack-Like Flaws

– Crack-like flaws are planar flaws which are predominantlycharacterized by a length and depth, with a sharp rootradius, the types of crack-like flaws are+ Surface breaking+ Embedded+ Through-wall

– In some cases, it is conservative and advisable to treatvolumetric flaws such as aligned porosity or inclusions,deep undercuts, root undercuts, and overlaps as planarflaws, particularly when such volumetric flaws maycontain microcracks at the root

– Grooves and gouges with a sharp root radius areevaluated using Section 9, criteria for the root radius is inSection 5

37


– Crack-like flaws are planar flaws which are predominantlycharacterized by a length and depth, with a sharp rootradius, the types of crack-like flaws are+ Surface breaking+ Embedded+ Through-wall

– In some cases, it is conservative and advisable to treatvolumetric flaws such as aligned porosity or inclusions,deep undercuts, root undercuts, and overlaps as planarflaws, particularly when such volumetric flaws maycontain microcracks at the root

– Grooves and gouges with a sharp root radius areevaluated using Section 9, criteria for the root radius is inSection 5



– The assessment procedures in Part 9 are based on afracture mechanics approach considering the entire rangeof material behavior+ Brittle fracture+ Elastic/plastic fracture+ Plastic collapse

– Information required to perform an assessment isprovided in Part 9 and the following Appendices+ Appendix C - Stress Intensity Factor Solutions+ Appendix D - Reference Stress Solutions+ Appendix E - Residual Stress Solutions+ Appendix F - Material Properties

38


– The assessment procedures in Part 9 are based on afracture mechanics approach considering the entire rangeof material behavior+ Brittle fracture+ Elastic/plastic fracture+ Plastic collapse

– Information required to perform an assessment isprovided in Part 9 and the following Appendices+ Appendix C - Stress Intensity Factor Solutions+ Appendix D - Reference Stress Solutions+ Appendix E - Residual Stress Solutions+ Appendix F - Material Properties


• Part 9: Crack-Like Flaws - Changes

– Appendix C - Stress Intensity Factor (K) Solutions+ Improved K solutions over larger range of geometries (Small

R/t)+ K solutions for shallow cracks a/t<0.2 improved

– Appendix E – New Residual Stress Solutions based onPVRC Residual Stress JIP research

– Appendix F - Material Properties, new methods toestimate fracture toughness based on MPC FFS JIPresearch co-funded by API

39

• Part 9: Crack-Like Flaws - Changes

– Appendix C - Stress Intensity Factor (K) Solutions+ Improved K solutions over larger range of geometries (Small

R/t)+ K solutions for shallow cracks a/t<0.2 improved

– Appendix E – New Residual Stress Solutions based onPVRC Residual Stress JIP research

– Appendix F - Material Properties, new methods toestimate fracture toughness based on MPC FFS JIPresearch co-funded by API


• Part 10: Creep (New)

– API 579, Part 10 provides assessment procedures forpressurized components operating in the creep range

– The temperature above which creep needs to beevaluated can be established using a Level 1 Assessment

– Assessment procedures for determining a remaining lifeare provided for components with and without a crack-like flaw subject to steady state and/or cyclic operatingconditions

– The procedures in this Part can be used to qualify acomponent for continued operation or for re-rating

40

• Part 10: Creep (New)

– API 579, Part 10 provides assessment procedures forpressurized components operating in the creep range

– The temperature above which creep needs to beevaluated can be established using a Level 1 Assessment

– Assessment procedures for determining a remaining lifeare provided for components with and without a crack-like flaw subject to steady state and/or cyclic operatingconditions

– The procedures in this Part can be used to qualify acomponent for continued operation or for re-rating


• Part 10: Creep (New)– Level 1 Assessment - Limitations

+ Component has been constructed to a recognized code orstandard

+ A history of the component can be provided covering bothpast and future operating conditions

+ The component has been subject to less than 50 cycles ofoperation including startup and shutdown conditions

+ The component does not contain a flaw such as an LTA,pitting or crack-like flaw

+ Component has not been subject to fire damage or anotheroverheating event that has resulted in a significant change inshape such as sagging or bulging, or excessive metal lossfrom scaling

+ The material meets or exceeds minimum hardness andcarbon content limitations

41






+ Component has not been subject to fire damage or anotheroverheating event that has resulted in a significant change inshape such as sagging or bulging, or excessive metal lossfrom scaling

+ The material meets or exceeds minimum hardness andcarbon content limitations

Overview of API/ASME 579-2006• Part 10: Creep (New)

– Level 1 Assessment – Calculations: single operatingcondition

1

10

100

600 700 800 900 1000 1100 1200TEM PERATURE, F

STR

ESS,

KSI 250,000 HRS

25,000 HRS2,500 HRS250 HRS25 HRS

42

1

10

100

600 700 800 900 1000 1100 1200TEM PERATURE, F

STR

ESS,

KSI 250,000 HRS

25,000 HRS2,500 HRS250 HRS25 HRS

Overview of API/ASME 579-2006• Part 10: Creep (New)

– Level 1 Assessment – Calculations: multiple operatingcondition

DAMAGE ISOTHERMS

1.00

10.00

1E-08 1E-07 1E-06 1E-05 1E-04 1E-03

DAMAGE RATE, FRACTIONAL DAMAGE/HR

STR

ESS,

KSI

750,F775,F800,F825,F850,F875,F900,F925,F950,F975,F1000,F1025,F1050,F1075,F

j j jc c seD R t

43

DAMAGE ISOTHERMS

1.00

10.00

1E-08 1E-07 1E-06 1E-05 1E-04 1E-03

DAMAGE RATE, FRACTIONAL DAMAGE/HR

STR

ESS,

KSI

750,F775,F800,F825,F850,F875,F900,F925,F950,F975,F1000,F1025,F1050,F1075,F

j j jc c seD R t

10.25

Jtotal jc c

jD D







– Level 2 Assessment - Calculations+ Analysis (i.e. FEA) used to determine temperature and stress

as a function of time

+ Material data and damage rule used to determineacceptability for continued operation

+ Method based on MPC Project Omega JIP

44






– Level 2 Assessment - Calculations+ Analysis (i.e. FEA) used to determine temperature and stress

as a function of time

+ Material data and damage rule used to determineacceptability for continued operation

+ Method based on MPC Project Omega JIP


• Part 11: Fire Damage– Covers assessment procedures for evaluating pressure

vessels, piping and tanks subjected to flameimpingement and the radiant heat of a fire

– Assessment procedures address the visually observablestructural degradation of components and the lessapparent degradation of mechanical properties, such asstrength, ductility, and toughness

– Assessment procedures may also be used to evaluateprocess upsets due to a chemical reaction within processvessels

• Part 11: Fire Damage - Changes– Reference provided to new Part 10 to evaluate creep

damage resulting from a fire

45

• Part 11: Fire Damage– Covers assessment procedures for evaluating pressure

vessels, piping and tanks subjected to flameimpingement and the radiant heat of a fire

– Assessment procedures address the visually observablestructural degradation of components and the lessapparent degradation of mechanical properties, such asstrength, ductility, and toughness

– Assessment procedures may also be used to evaluateprocess upsets due to a chemical reaction within processvessels

• Part 11: Fire Damage - Changes– Reference provided to new Part 10 to evaluate creep

damage resulting from a fire


• Part 12: Dents, Gouges, and Dent-GougeCombinations (New)– Assessment procedures for pressurized components

containing dents, gouges, or dent-gouge combinationsresulting from mechanical damage

– Dent – An inward or outward deviation of a cross-sectionof a shell member from an ideal shell geometry that ischaracterized by a small local radius or notch

– Gouge – An elongated local removal and/or relocation ofmaterial from the surface of a component caused bymechanical means that results in a reduction in wallthickness; the material may have been cold worked inthe formation of the flaw

– Dent-Gouge Combination – A dent with a gouge presentin the deformed region

46

• Part 12: Dents, Gouges, and Dent-GougeCombinations (New)– Assessment procedures for pressurized components

containing dents, gouges, or dent-gouge combinationsresulting from mechanical damage

– Dent – An inward or outward deviation of a cross-sectionof a shell member from an ideal shell geometry that ischaracterized by a small local radius or notch

– Gouge – An elongated local removal and/or relocation ofmaterial from the surface of a component caused bymechanical means that results in a reduction in wallthickness; the material may have been cold worked inthe formation of the flaw

– Dent-Gouge Combination – A dent with a gouge presentin the deformed region


• Part 12: Dents, Gouges, and Dent-GougeCombinations (New)– Assessment procedures permit calculation of MAWP or

MFH– Level 1 Assessment Procedures based on simple

screening criteria– Level 2 Assessment Procedures require some stress

analysis, fatigue calculation method included for dent anddent-gouge combinations

47

• Part 12: Dents, Gouges, and Dent-GougeCombinations (New)– Assessment procedures permit calculation of MAWP or

MFH– Level 1 Assessment Procedures based on simple

screening criteria– Level 2 Assessment Procedures require some stress

analysis, fatigue calculation method included for dent anddent-gouge combinations


• Part 13: Laminations (New)– Covers assessment procedures for pressurized

components with laminations, excluding HIC or SOHICdamage

– Laminations are defined as a plane of non-fusion in theinterior of a steel plate that results during the steelmanufacturing process

– Existing assessment procedures in Part 7 will besignificantly updated

48

• Part 13: Laminations (New)– Covers assessment procedures for pressurized

components with laminations, excluding HIC or SOHICdamage

– Laminations are defined as a plane of non-fusion in theinterior of a steel plate that results during the steelmanufacturing process

– Existing assessment procedures in Part 7 will besignificantly updated

Overview of API/ASME 579-2006• Appendices – updates previously discussed have been

completed– Appendix B – Stress Analysis Overview for a FFS Assessment -

Change, complete rewrite to incorporate new elastic-plasticanalysis methods and fatigue evaluation technology developedfor the ASME Div 2 Re-write Project

– Appendix C – Compendium of Stress Intensity Factor Solutions -Change, new stress intensity factor solutions for thick wallcylinders, through wall cracks in cylinders and spheres, holes inplates

– Appendix E - Compendium of Residual Stress Solutions -Change, complete rewrite to incorporate new solutionsdeveloped by PVRC Joint Industry Project

– Appendix F – Material Properties for a FFS Assessment -Change, new fracture toughness estimation methods and stress-strain curve model incorporated

– Appendix H – Technical Basis and Validation of FFS Procedures –NEW, technical basis document that provides an overview of thetechnical background and validation with essential references

– Appendix K – Crack Opening Areas - NEW, appendix coveringcrack opening areas for through-wall flaws in cylinders andspheres

49

• Appendices – updates previously discussed have beencompleted– Appendix B – Stress Analysis Overview for a FFS Assessment -

Change, complete rewrite to incorporate new elastic-plasticanalysis methods and fatigue evaluation technology developedfor the ASME Div 2 Re-write Project

– Appendix C – Compendium of Stress Intensity Factor Solutions -Change, new stress intensity factor solutions for thick wallcylinders, through wall cracks in cylinders and spheres, holes inplates

– Appendix E - Compendium of Residual Stress Solutions -Change, complete rewrite to incorporate new solutionsdeveloped by PVRC Joint Industry Project

– Appendix F – Material Properties for a FFS Assessment -Change, new fracture toughness estimation methods and stress-strain curve model incorporated

– Appendix H – Technical Basis and Validation of FFS Procedures –NEW, technical basis document that provides an overview of thetechnical background and validation with essential references

– Appendix K – Crack Opening Areas - NEW, appendix coveringcrack opening areas for through-wall flaws in cylinders andspheres

• Technology Development Efforts Currently Underway– Documentation of validation of new assessment procedures

for HIC/SOHIC damage (2006)– Allowable Remaining Strength Factor (RSFa) calibration

based on original construction code (2006)– Assessment of local thin areas (2007)

+ Development of a new method for computing the RSF factor forboth Level 1 and Level 2 Assessments

+ Development of new LTA-to-LTA spacing criteria+ Development of new LTA-to-structural discontinuities spacing

criteria+ Development of new rules for assessment of local thin areas at

nozzles and other shell discontinuities

– Completion of Example Problems Manual (2007)

Future Enhancements After the 2006Publication of API/ASME 579

50

• Technology Development Efforts Currently Underway– Documentation of validation of new assessment procedures

for HIC/SOHIC damage (2006)– Allowable Remaining Strength Factor (RSFa) calibration

based on original construction code (2006)– Assessment of local thin areas (2007)

+ Development of a new method for computing the RSF factor forboth Level 1 and Level 2 Assessments

+ Development of new LTA-to-LTA spacing criteria+ Development of new LTA-to-structural discontinuities spacing

criteria+ Development of new rules for assessment of local thin areas at

nozzles and other shell discontinuities

– Completion of Example Problems Manual (2007)


• Technology Development Efforts Currently Underway– Assessment Procedures for bulges (2007)– Assessment of crack-like flaws (2007)

+ New PSF (Partial Safety Factors) for crack-like flaws,introduction of PSF’s for LTA’s

+ Development of new reference stress solutions based on J-Integral Technique

+ Evaluation of weld mismatch effects

– Assessment procedures for HTHA (2007)– Assessment procedures for hot-spots (2008)– Assessment of damage in cast iron components (paper

mill dryers) (2008)

51

• Technology Development Efforts Currently Underway– Assessment Procedures for bulges (2007)– Assessment of crack-like flaws (2007)

+ New PSF (Partial Safety Factors) for crack-like flaws,introduction of PSF’s for LTA’s

+ Development of new reference stress solutions based on J-Integral Technique

+ Evaluation of weld mismatch effects

– Assessment procedures for HTHA (2007)– Assessment procedures for hot-spots (2008)– Assessment of damage in cast iron components (paper

mill dryers) (2008)


• Future Technology Needs– Improved fracture toughness evaluation for in-service

materials+ Carbon steel and low alloys+ Environmental effects (e.g. hydrogen)+ Temperature dependency+ Statistical evaluation

– Improved assessment procedures for dents and dent-gouge combinations+ Removal of geometry restrictions+ Coverage of more materials+ Coverage of more loading types

– Evaluation of material toughness effects on the burstpressure of components with non-crack-like flaws (i.e.LTAs, pitting)

52

• Future Technology Needs– Improved fracture toughness evaluation for in-service

materials+ Carbon steel and low alloys+ Environmental effects (e.g. hydrogen)+ Temperature dependency+ Statistical evaluation

– Improved assessment procedures for dents and dent-gouge combinations+ Removal of geometry restrictions+ Coverage of more materials+ Coverage of more loading types

– Evaluation of material toughness effects on the burstpressure of components with non-crack-like flaws (i.e.LTAs, pitting)

• Future Technology Needs– Assessment Procedures for Crack-Like Flaws

+ FAD dependency on stress-strain curve+ Evaluation of pressure test and warm pre-stress effects+ Improved crack growth models, including data, considering

environmental efforts

– Assessment Procedures for Fatigue+ Multiaxial fatigue+ Cycle counting+ Environmental effects

– Assessment Procedures for Creep Damage+ Include primary creep in MPC Project Omega Creep Model+ Creep damage from triaxial stress states+ Development of new procedures to evaluate creep-fatigue

damage+ New procedures to evaluate creep-buckling


53

• Future Technology Needs– Assessment Procedures for Crack-Like Flaws

+ FAD dependency on stress-strain curve+ Evaluation of pressure test and warm pre-stress effects+ Improved crack growth models, including data, considering

environmental efforts

– Assessment Procedures for Fatigue+ Multiaxial fatigue+ Cycle counting+ Environmental effects

– Assessment Procedures for Creep Damage+ Include primary creep in MPC Project Omega Creep Model+ Creep damage from triaxial stress states+ Development of new procedures to evaluate creep-fatigue

damage+ New procedures to evaluate creep-buckling


• Future Technology Needs– Improved Stress-Strain Models

+ Temperature Effects+ Loading Rate Effects+ Cyclic Stress-Strain Curves

– Introduction of partial safety factors for other types ofdamage (i.e. LTA, pitting)

– Additional stress intensity factor solutions for commonpressurized component geometries (e.g. cracks atnozzles)

54

• Future Technology Needs– Improved Stress-Strain Models

+ Temperature Effects+ Loading Rate Effects+ Cyclic Stress-Strain Curves

– Introduction of partial safety factors for other types ofdamage (i.e. LTA, pitting)

– Additional stress intensity factor solutions for commonpressurized component geometries (e.g. cracks atnozzles)

Technical Basis and Validation ofAPI/ASME 579 FFS Assessment

Methods

• The API CRE FFS and Joint API/ASME Committees arecommitted to publishing the technical basis to all FFSassessment procedures utilized in API 579 in the publicdomain

• It is hoped that other FFS standards writing committeesadopt the same policy as it is crucial that FFS knowledgeremains at the forefront of technology on an internationalbasis to facilitate adoption by jurisdictional authorities

• The new API 579 Appendix H of API 579 provides anoverview of technical basis and validation with relatedreferences organized by damage type, the references arepublished in a series of WRC Bulletins and technical papers

55

• The API CRE FFS and Joint API/ASME Committees arecommitted to publishing the technical basis to all FFSassessment procedures utilized in API 579 in the publicdomain

• It is hoped that other FFS standards writing committeesadopt the same policy as it is crucial that FFS knowledgeremains at the forefront of technology on an internationalbasis to facilitate adoption by jurisdictional authorities

• The new API 579 Appendix H of API 579 provides anoverview of technical basis and validation with relatedreferences organized by damage type, the references arepublished in a series of WRC Bulletins and technical papers

• WRC Bulletins Published– Review of Existing Fitness-For-Service Criteria for Crack-Like Flaws

(WRC 430)– Technologies for the Evaluation of Non-Crack-Like Flaws in

Pressurized Components - Erosion/Corrosion, Pitting, Blisters, ShellOut-of-Roundness, Weld Misalignment, Bulges, and Dents inPressurized Components (WRC 465)

– Development of Stress Intensity Factor Solutions for Surface andEmbedded Cracks in API 579 (WRC 471)

– Stress Intensity and Crack Growth Opening Area Solutions forThrough-wall Cracks in Cylinders and Spheres (WRC 478)

– Recent Progress in Analysis of Welding Residual Stresses (WRC 455)– Recommendations for Determining Residual Stresses in Fitness-For-

Service Assessments (WRC 476)– Master S-N Curve Method for Fatigue Evaluation of Welded

Components (WRC 474)


Methods

56

• WRC Bulletins Published– Review of Existing Fitness-For-Service Criteria for Crack-Like Flaws

(WRC 430)– Technologies for the Evaluation of Non-Crack-Like Flaws in

Pressurized Components - Erosion/Corrosion, Pitting, Blisters, ShellOut-of-Roundness, Weld Misalignment, Bulges, and Dents inPressurized Components (WRC 465)

– Development of Stress Intensity Factor Solutions for Surface andEmbedded Cracks in API 579 (WRC 471)

– Stress Intensity and Crack Growth Opening Area Solutions forThrough-wall Cracks in Cylinders and Spheres (WRC 478)

– Recent Progress in Analysis of Welding Residual Stresses (WRC 455)– Recommendations for Determining Residual Stresses in Fitness-For-

Service Assessments (WRC 476)– Master S-N Curve Method for Fatigue Evaluation of Welded

Components (WRC 474)

• WRC Bulletins Pending– Compendium of Temperature-Dependent Physical Properties for

Pressure Vessel Materials (WRC 503)

– An Overview and Validation of The Fitness-For-Service AssessmentProcedures for Locally Thin Areas in API 579 (WRC 505)


Methods

57

• WRC Bulletins Pending– Compendium of Temperature-Dependent Physical Properties for

Pressure Vessel Materials (WRC 503)

– An Overview and Validation of The Fitness-For-Service AssessmentProcedures for Locally Thin Areas in API 579 (WRC 505)


Methods

• WRC Bulletins In Preparation– An Overview of The Fitness-For-Service Assessment Procedures

for Pitting Damage in API 579

– An Overview of the Fitness-For-Service Assessment Proceduresfor Weld Misalignment and Shell Distortions in API 579

– An Overview and Validation of the Fitness-For-ServiceAssessment Procedures for Crack-Like Flaws in API 579

– An Overview and Validation of Residual Stress Distributions forUse in the Assessment Procedures of Crack-Like Flaws in API579

– An Overview and validation of the Fitness-For-Service Rules forthe Assessment of HIC/SOHIC Damage in API 579

58

• WRC Bulletins In Preparation– An Overview of The Fitness-For-Service Assessment Procedures

for Pitting Damage in API 579

– An Overview of the Fitness-For-Service Assessment Proceduresfor Weld Misalignment and Shell Distortions in API 579

– An Overview and Validation of the Fitness-For-ServiceAssessment Procedures for Crack-Like Flaws in API 579

– An Overview and Validation of Residual Stress Distributions forUse in the Assessment Procedures of Crack-Like Flaws in API579

– An Overview and validation of the Fitness-For-Service Rules forthe Assessment of HIC/SOHIC Damage in API 579


Methods

• WRC Bulletins In Preparation– MPC Project Omega and Procedures for Assessment of Creep

Damage in API 579

– Development of a Local Strain Criteria Based on the MPCUniversal Stress-Strain Equation

– Update on the Master S-N Curve Method for Fatigue Evaluationof Welded Components

59

• WRC Bulletins In Preparation– MPC Project Omega and Procedures for Assessment of Creep

Damage in API 579

– Development of a Local Strain Criteria Based on the MPCUniversal Stress-Strain Equation

– Update on the Master S-N Curve Method for Fatigue Evaluationof Welded Components

Understanding of DamageMechanisms

• The first step in a Fitness-For-Service assessmentperformed in accordance with API 579 is to identify theflaw type and associated damage mechanism

• Appendix G in API 579 provides basic information to assistthe practitioner in this step

• The following WRC Bulletins have been produced toprovide the practitioner with in-depth information

– Damage Mechanisms Affecting Fixed Equipment in the Pulp andPaper Industry (WRC 488)

– Damage Mechanisms Affecting Fixed Equipment in the RefiningIndustry (WRC 489 & API RP 571)

– Damage Mechanisms Affecting Fixed Equipment in the FossilElectric Power Industry (WRC 490)

60

• The first step in a Fitness-For-Service assessmentperformed in accordance with API 579 is to identify theflaw type and associated damage mechanism

• Appendix G in API 579 provides basic information to assistthe practitioner in this step

• The following WRC Bulletins have been produced toprovide the practitioner with in-depth information

– Damage Mechanisms Affecting Fixed Equipment in the Pulp andPaper Industry (WRC 488)

– Damage Mechanisms Affecting Fixed Equipment in the RefiningIndustry (WRC 489 & API RP 571)

– Damage Mechanisms Affecting Fixed Equipment in the FossilElectric Power Industry (WRC 490)

In-Service Inspection Codesand Fitness-For-Service

• Jurisdictional acceptance provided by reference from in-service inspection codes in the US– API 510 – Vessels– API 570 – Piping– API 653 – Tankage– ANSI/NB-23 – Vessels & Boilers

• Status of reference from US inspection codes is asfollows:– API 510 – Reference in 8th Edition, 2nd Addendum– API 570 – Reference in 2nd Edition, 2nd Addendum– API 653 – Reference to appear in 3rd Edition, 1st Addendum– ANSI/NB-23 – Reference in Introduction of 2001 Addendum

• Working to achieve recognition by other internationalin-service inspections codes

61

• Jurisdictional acceptance provided by reference from in-service inspection codes in the US– API 510 – Vessels– API 570 – Piping– API 653 – Tankage– ANSI/NB-23 – Vessels & Boilers

• Status of reference from US inspection codes is asfollows:– API 510 – Reference in 8th Edition, 2nd Addendum– API 570 – Reference in 2nd Edition, 2nd Addendum– API 653 – Reference to appear in 3rd Edition, 1st Addendum– ANSI/NB-23 – Reference in Introduction of 2001 Addendum

• Working to achieve recognition by other internationalin-service inspections codes

In-Service Inspection Codesand Fitness-For-Service

• Reactive FFS can be used to assess damage found duringan inspection; provides basis for run, repair, or replacedecision

• Proactive FFS can be used prior to shut-downs to helpdevelop inspection plans (e.g. determine maximumpermissible flaws sizes)

• The remaining life is determined as part of an FFSassessment:

– Used to establish an inspection interval

– Half-life or similar concepts can be used

– “Snap-Shot” approach to FFS is not adequate, an evaluation of thetime dependency of damage is required

62

• Reactive FFS can be used to assess damage found duringan inspection; provides basis for run, repair, or replacedecision

• Proactive FFS can be used prior to shut-downs to helpdevelop inspection plans (e.g. determine maximumpermissible flaws sizes)

• The remaining life is determined as part of an FFSassessment:

– Used to establish an inspection interval

– Half-life or similar concepts can be used

– “Snap-Shot” approach to FFS is not adequate, an evaluation of thetime dependency of damage is required

Fitness-For-Service and RBI -Complimentary Technologies

• Assessment of damage in many of the RBI methodscurrently being used is needs updating; is not consistentwith FFS assessment procedures

• Documented and validated FFS methods for flaw anddamage assessment may be used to establish a probabilityof failure as a function of time by considering uncertaintiesin the damage model and independent variables

• The resulting probably of failure can be combined with aconsequence model to produce an estimate of risk as afunction of time

• Time dependency of risk permits development of aninspection plan

• Work is underway to integrate API 579 with API 581

63

• Assessment of damage in many of the RBI methodscurrently being used is needs updating; is not consistentwith FFS assessment procedures

• Documented and validated FFS methods for flaw anddamage assessment may be used to establish a probabilityof failure as a function of time by considering uncertaintiesin the damage model and independent variables

• The resulting probably of failure can be combined with aconsequence model to produce an estimate of risk as afunction of time

• Time dependency of risk permits development of aninspection plan

• Work is underway to integrate API 579 with API 581

Harmonizing Pressure Vessel Design andFitness-For-Service

• To remain technically competitive, and to facilitateincorporation of new technology and future updates, ASME isdeveloping a new pressure Vessel Code; this code will replacethe existing Section VIII, Division 2 Code

• The new code is being developed primarily to address designand fabrication “of engineered” pressure vessels (as typicallyused in the refining and petrochemical industry); will result insignificant cost savings

• The new code is consistent with developments in Europe

• Objective to develop a new organization and introduce a clearand consistent writing style to facilitate use; consistent withAPI-579 philosophy

• Shared technology between API-579 and new design Code.

• Draft version of new Code is complete; work is underway toballot the Div 2 Rewrite in 2006

64

• To remain technically competitive, and to facilitateincorporation of new technology and future updates, ASME isdeveloping a new pressure Vessel Code; this code will replacethe existing Section VIII, Division 2 Code

• The new code is being developed primarily to address designand fabrication “of engineered” pressure vessels (as typicallyused in the refining and petrochemical industry); will result insignificant cost savings

• The new code is consistent with developments in Europe

• Objective to develop a new organization and introduce a clearand consistent writing style to facilitate use; consistent withAPI-579 philosophy

• Shared technology between API-579 and new design Code.

• Draft version of new Code is complete; work is underway toballot the Div 2 Rewrite in 2006

Summary• Fitness-For-Service (FFS) assessments are quantitative

engineering evaluations that are performed to demonstratethe structural integrity of an in-service component containinga flaw or damage

• API and ASME have agreed to form a joint committee toproduce a single FFS Standard, API/ASME 579, that can beused for pressure-containing equipment– Permits focusing of resources in the US to develop a single

document that can be used by all industries– Helps avoid jurisdictional conflicts and promotes uniform

acceptance of FFS technology• The 2006 edition of API/ASME 579 represents a significant

update in assessment procedures• The technical basis and validation of the API/ASME 579 FFS

assessment procedures will be published in the public domain• API/ASME 579 FFS assessment methods have been integrated

with API & NBIC inspection codes and will be integrated intoAPI RBI technologies

• Significant technical development work remains and a workplan is being formulated

65

• Fitness-For-Service (FFS) assessments are quantitativeengineering evaluations that are performed to demonstratethe structural integrity of an in-service component containinga flaw or damage

• API and ASME have agreed to form a joint committee toproduce a single FFS Standard, API/ASME 579, that can beused for pressure-containing equipment– Permits focusing of resources in the US to develop a single

document that can be used by all industries– Helps avoid jurisdictional conflicts and promotes uniform

acceptance of FFS technology• The 2006 edition of API/ASME 579 represents a significant

update in assessment procedures• The technical basis and validation of the API/ASME 579 FFS

assessment procedures will be published in the public domain• API/ASME 579 FFS assessment methods have been integrated

with API & NBIC inspection codes and will be integrated intoAPI RBI technologies

• Significant technical development work remains and a workplan is being formulated

Robert Brown, P.E.FFS Team Leader216-283-6015

[email protected]

20600 Chagrin Blvd. • Suite 1200Shaker Heights, OH 44122 USA

Phone: 216-283-9519 • Fax: 216-283-6022www.equityeng.com

66

Robert Brown, P.E.FFS Team Leader216-283-6015

[email protected]

20600 Chagrin Blvd. • Suite 1200Shaker Heights, OH 44122 USA

Phone: 216-283-9519 • Fax: 216-283-6022www.equityeng.com

5 api 579 compatibility mode

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