مجتبی ورشاوی
عضو جدید
The table of contents for the new code incorporates a modular flat structure to facilitate modifications and enhancements
–Part 1 –General Requirements
–Part 2 –Responsibilities and Duties
–Part 3 –Materials Requirements
–Part 4 –Design By Rule Requirements
–Part 5 –Design By Analysis Requirements
–Part 6 –Fabrication Requirements
–Part 7 –Examination and Inspection Requirements
–Part 8 –Pressure Testing Requirements
–Part 9 –Pressure Vessel Overpressure Protection
•Technical information traditionally placed in Mandatory and Non-Mandatory Appendices at the back of the existing Code will be re-deployed as Annex’s to Parts in the new Code with a similar topic
Part 1 –General Requirements
Introduction, Organization and Definitions
Scope and Jurisdiction
Pressure Vessels with High Design Pressures
Unfired Steam Boilers
Field Assembly
Referenced Standards
Units of Measure, Metric and US Customary
Part 2 –Duties and Responsibilities
•User responsibilities
•Manufacturers responsibilities
•Inspectors duties
•Annexes on User Design Specification (UDS) and the Manufacturers Design Report (MDR)
•Separation of administrative and technical requirements, administrative requirements placed in Informative Annexes
Part 2 –Duties and Responsibilities
•UDS and MDR –Registered Professional Engineer (RPE) requirement
–RPE certification has been in the Code since the first issuance; however, codes and standards covering similar equipment do not require RPE certification (e.g. ASME Div. 1, ASME B31.3, API, European, etc.)
–RPE certification is unique to USA and Canada
–Industry questionnaire confirmed that RPE certification of UDS and MDR is a barrier to the use of the existing Div 2
•Alternative to the RPE certification developed -Certification of Compliance approach, certification of the UDS and MDR by the individuals in responsible charge of the design and manufacture of the vessel
Part 3 –Material Requirements
•New allowable stress basis will typically result in higher allowable stresses and lower wall thickness, extent of wall thickness reduction is a function of the YS/TS ratio at the design temperature
•Justification for higher allowable stresses and reduced wall thickness
–Experience obtained from other PV construction codes
–More stringent material requirements
–Higher material toughness requirement
–Better design rules
–Increased NDE
•New material models for strength parameters (i.e. stress-strain curves) and physical properties provided to facilitate design and numerical analysis requirements
Part 3 –Material Requirements
•Modernization of toughness rules -new rules will require higher toughness, CVN=20 ft-lbs minimum
•New toughness rules based on a rigorous fracture mechanics approach
–Required material toughness developed in terms of
driving force based on API 579-1/ASME FFS-1, Part
approach, considers:
Reference flaw
Primary stress
Residual stress
–Required material resistance developed in terms of
required CVN, CVN will be a function of:
Material (generic type, heat treatment, yield strength)
Temperature
Thickness
Part 4 –Design By Rule Requirements
•Consolidation of design requirements for welds
•New design methods
–Cylindrical and spherical shell thickness equations
–Elliptical and torispherical heads (ASME Code Case 2260)
–Combined loadings (pressure and net-section axial forces, shear forces, bending moments, and torsion)
–Junctions at conical transitions including junctions with a stiffening ring and/or knuckle
–Shells subject to external pressure (ASME Code Case 2286)
–Evaluation of compressive stresses from combined loadings (ASME Code Case 2286)
–New nozzle reinforcement design rules for internal/external pressure
•Inclusion of existing design methods:
–Layered construction
–Non-circular vessels (ASME Section VIII, Div 1)
–Lug-type, saddle, and skirt supports (industry accepted procedures, e.g. Zick’s analysis for saddle supports)
–Rules to evaluate vessels that are outside of tolerances based on API 579-1/ASME FFS-1 2007, Fitness-For-Service
–Expansion joints (ASME Div 1 rules)
–Tubesheets (ASME Div 1 rules)
•Part 4 may be used for design of components in the creep range
•Many vessels may be designed using Part 4 without the need for design-by-analysis (Part 5)
•Weld joint efficiency option introduced; the weld joint efficiency will appear explicitly in the design equations as SE, similar to Div 1
•Weld joint efficiencies –significant differences exist between the new Div 2 Code and existing ASME Codes
–Div 2, 2007 Edition –weld joint efficiencies are a function of material testing group, NDE method and extent of examination, wall thickness, welding process, and service temperature
–Div 2, 2006 Edition –100% examination
–Div 1, 2006 Edition –weld joint efficiencies are a function of extent of examination and weld type; mixed extent of examination is permitted (RT1, RT2, RT3, and RT4)
Part 5 –Design By Analysis Requirements
•Complete re-organization of Design-By-Analysis (DBA) methods based on prevention of failure modes
–Plastic Collapse
–Local Failure (strain limit)
–Collapse From Buckling
–Fatigue
•Modernization of DBA methods to accommodate advances in numerical analysis (i.e. FEA)
•Continued use of Hopper Diagram with elastic stress analysis
•Design procedures to prevent plastic collapse using limit load or elastic-plastic stress analysis based on Load Resistance Factor Design (LRFD) concepts
•Fatigue Analysis
–Screening criteria for fatigue analysis requirement provided
–Continued use of fatigue analysis based on smooth bar data
–New design rules for fatigue based on elastic-plastic analysis
–Inclusion of new welded joint fatigue method using the Equivalent Structural Stress and Master Fatigue Curve approach developed by Battelle (WRC 474)
–New cycle counting procedures
•Part 5 analysis methods can be used for design of all components that are not operating in the creep range
•Basic wall thickness equations in Part 4 need not be satisfied if a thinner thickness can be determined using DBA methods in Part 5
Part 6 –Fabrication Requirements
•Similar fabrication requirements to the existing Div 2
•New fabrication tolerances; if tolerances are exceeded an evaluation may be performed using API 579-1/ASME FFS-1 Fitness-For-Service
•Similar PWHT requirements are planned for the initial release; however, development of new time-temperature-thickness criterion for PWHT is under development by PVRC
Part 7 –ExaminationRequirements
•Introduction of Testing Group concept todefine NDE requirements and weld joint efficiency
•Inclusion and new definition of partial radiography
–Div 1: approximately 1% coverage
–Div 2, 2007: 10% coverage
•Ultrasonic NDE may be substituted for radiographic NDE for weld examination
Part 9 –Overpressure Protection
•Complete reorganization, utilizes the requirements of Section VIII, Div 1 by reference
•Inclusion of Code Case 2211 philosophy (system design in lieu of pressure relief)
•Update to isolation valve strategy to match what is currently in Appendix M of Section VIII, Div 1
Comparison
ASME Section VIII, Div 2: 2006 vs. 2007
•New allowable stress basis will typically result in higher allowable stresses and lower wall thickness, extent of wall thickness reduction is a function of the YS/TS ratio at the design temperature
•Increase in allowable stress and resulting Wall Thickness Reduction (WTR) may be significant for many materials, indicator is the MYS/MTS ratio
•Consider the following comparison:
–Design pressure: 1000 psig
–Inside diameter: 60 inches
–Weld joint efficiency: 1.0
–Part 1 –General Requirements
–Part 2 –Responsibilities and Duties
–Part 3 –Materials Requirements
–Part 4 –Design By Rule Requirements
–Part 5 –Design By Analysis Requirements
–Part 6 –Fabrication Requirements
–Part 7 –Examination and Inspection Requirements
–Part 8 –Pressure Testing Requirements
–Part 9 –Pressure Vessel Overpressure Protection
•Technical information traditionally placed in Mandatory and Non-Mandatory Appendices at the back of the existing Code will be re-deployed as Annex’s to Parts in the new Code with a similar topic
Part 1 –General Requirements
Introduction, Organization and Definitions
Scope and Jurisdiction
Pressure Vessels with High Design Pressures
Unfired Steam Boilers
Field Assembly
Referenced Standards
Units of Measure, Metric and US Customary
Part 2 –Duties and Responsibilities
•User responsibilities
•Manufacturers responsibilities
•Inspectors duties
•Annexes on User Design Specification (UDS) and the Manufacturers Design Report (MDR)
•Separation of administrative and technical requirements, administrative requirements placed in Informative Annexes
Part 2 –Duties and Responsibilities
•UDS and MDR –Registered Professional Engineer (RPE) requirement
–RPE certification has been in the Code since the first issuance; however, codes and standards covering similar equipment do not require RPE certification (e.g. ASME Div. 1, ASME B31.3, API, European, etc.)
–RPE certification is unique to USA and Canada
–Industry questionnaire confirmed that RPE certification of UDS and MDR is a barrier to the use of the existing Div 2
•Alternative to the RPE certification developed -Certification of Compliance approach, certification of the UDS and MDR by the individuals in responsible charge of the design and manufacture of the vessel
Part 3 –Material Requirements
•New allowable stress basis will typically result in higher allowable stresses and lower wall thickness, extent of wall thickness reduction is a function of the YS/TS ratio at the design temperature
•Justification for higher allowable stresses and reduced wall thickness
–Experience obtained from other PV construction codes
–More stringent material requirements
–Higher material toughness requirement
–Better design rules
–Increased NDE
•New material models for strength parameters (i.e. stress-strain curves) and physical properties provided to facilitate design and numerical analysis requirements
Part 3 –Material Requirements
•Modernization of toughness rules -new rules will require higher toughness, CVN=20 ft-lbs minimum
•New toughness rules based on a rigorous fracture mechanics approach
–Required material toughness developed in terms of
driving force based on API 579-1/ASME FFS-1, Part
approach, considers:
Reference flaw
Primary stress
Residual stress
–Required material resistance developed in terms of
required CVN, CVN will be a function of:
Material (generic type, heat treatment, yield strength)
Temperature
Thickness
Part 4 –Design By Rule Requirements
•Consolidation of design requirements for welds
•New design methods
–Cylindrical and spherical shell thickness equations
–Elliptical and torispherical heads (ASME Code Case 2260)
–Combined loadings (pressure and net-section axial forces, shear forces, bending moments, and torsion)
–Junctions at conical transitions including junctions with a stiffening ring and/or knuckle
–Shells subject to external pressure (ASME Code Case 2286)
–Evaluation of compressive stresses from combined loadings (ASME Code Case 2286)
–New nozzle reinforcement design rules for internal/external pressure
•Inclusion of existing design methods:
–Layered construction
–Non-circular vessels (ASME Section VIII, Div 1)
–Lug-type, saddle, and skirt supports (industry accepted procedures, e.g. Zick’s analysis for saddle supports)
–Rules to evaluate vessels that are outside of tolerances based on API 579-1/ASME FFS-1 2007, Fitness-For-Service
–Expansion joints (ASME Div 1 rules)
–Tubesheets (ASME Div 1 rules)
•Part 4 may be used for design of components in the creep range
•Many vessels may be designed using Part 4 without the need for design-by-analysis (Part 5)
•Weld joint efficiency option introduced; the weld joint efficiency will appear explicitly in the design equations as SE, similar to Div 1
•Weld joint efficiencies –significant differences exist between the new Div 2 Code and existing ASME Codes
–Div 2, 2007 Edition –weld joint efficiencies are a function of material testing group, NDE method and extent of examination, wall thickness, welding process, and service temperature
–Div 2, 2006 Edition –100% examination
–Div 1, 2006 Edition –weld joint efficiencies are a function of extent of examination and weld type; mixed extent of examination is permitted (RT1, RT2, RT3, and RT4)
Part 5 –Design By Analysis Requirements
•Complete re-organization of Design-By-Analysis (DBA) methods based on prevention of failure modes
–Plastic Collapse
–Local Failure (strain limit)
–Collapse From Buckling
–Fatigue
•Modernization of DBA methods to accommodate advances in numerical analysis (i.e. FEA)
•Continued use of Hopper Diagram with elastic stress analysis
•Design procedures to prevent plastic collapse using limit load or elastic-plastic stress analysis based on Load Resistance Factor Design (LRFD) concepts
•Fatigue Analysis
–Screening criteria for fatigue analysis requirement provided
–Continued use of fatigue analysis based on smooth bar data
–New design rules for fatigue based on elastic-plastic analysis
–Inclusion of new welded joint fatigue method using the Equivalent Structural Stress and Master Fatigue Curve approach developed by Battelle (WRC 474)
–New cycle counting procedures
•Part 5 analysis methods can be used for design of all components that are not operating in the creep range
•Basic wall thickness equations in Part 4 need not be satisfied if a thinner thickness can be determined using DBA methods in Part 5
Part 6 –Fabrication Requirements
•Similar fabrication requirements to the existing Div 2
•New fabrication tolerances; if tolerances are exceeded an evaluation may be performed using API 579-1/ASME FFS-1 Fitness-For-Service
•Similar PWHT requirements are planned for the initial release; however, development of new time-temperature-thickness criterion for PWHT is under development by PVRC
Part 7 –ExaminationRequirements
•Introduction of Testing Group concept todefine NDE requirements and weld joint efficiency
•Inclusion and new definition of partial radiography
–Div 1: approximately 1% coverage
–Div 2, 2007: 10% coverage
•Ultrasonic NDE may be substituted for radiographic NDE for weld examination
Part 9 –Overpressure Protection
•Complete reorganization, utilizes the requirements of Section VIII, Div 1 by reference
•Inclusion of Code Case 2211 philosophy (system design in lieu of pressure relief)
•Update to isolation valve strategy to match what is currently in Appendix M of Section VIII, Div 1
Comparison
ASME Section VIII, Div 2: 2006 vs. 2007
•New allowable stress basis will typically result in higher allowable stresses and lower wall thickness, extent of wall thickness reduction is a function of the YS/TS ratio at the design temperature
•Increase in allowable stress and resulting Wall Thickness Reduction (WTR) may be significant for many materials, indicator is the MYS/MTS ratio
•Consider the following comparison:
–Design pressure: 1000 psig
–Inside diameter: 60 inches
–Weld joint efficiency: 1.0
