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ASME BPVC 2021 General Change to Sections I, IV, VIII (Divisions 1, 2 and 3), X and XII


ASME BPVC 2021 General Change to Sections I, IV, VIII (Divisions 1, 2 and 3), X and XII ASME Boiler & Pressure Vessel Code 2021 Edition was issued on July 1, 2021. However it will become mandatory 6 months after the date or issuance/release. Today, more than ever, Code users around the world - boiler/pressure vessel manufacturers, operators, stamp holders and inspectors should be carefully reviewed and verified on the updated Edition for compliance with Code requirements to ensure safety and quality.


Here, we are discussing about general changes to ASME BPVC 2021 Edition. In new Release, a new section is adopted, ASME BPVC Section XIII for Rules for Overpressure Protection. Also Revisions to Sections I, IV, VIII (Divisions 1, 2 and 3), X and XII have been issued which includes the transfer of pressure relief device requirements. The remaining overpressure protection requirements have been restructured; cross-references updated; and new Appendices added to list the new locations for all those requirements, formerly located in each of the Sections.


Major changes to Section I are:

  • Revised Figure PG-33.2 sketch (c) to depict d as the OD of the nozzle, in addition to reinstating Figure PW-16.1(Z) sketches as a new sketch (j).

  • Revised Figures PG-58.2-1 and PG-58.2-6 by deleting the flow arrow for miscellaneous piping connections, in addition to replacing “Chemical Feed” and “Drum Sampling” references with “Water Treatment”.

  • Revised PG-58.3.1 to further clarify the limits of BEP for a single installation.

  • Revised PW-39.1 to add a reference to Table PW-39.2, addressing temperature ranges for dissimilar and similar weld joints.

General Changes to Section II are:

  • Updated the range of acceptable ASTM editions for a number of specifications and also updated the Guidelines on the Approval of New Materials Under the ASME BPVC. In Section II, Part A, updated the latest adopted edition have been made to over 15 specifications. The two new specification added are SA-988/SA-988M and SA-989/SA-989M. Also, SA/NFA 36-215 specification removed.

  • In Section II, Part B, updates to 45 specifications have been made. SB-752/SB-752M and SB-834 are added and SB-858 is removed.

In Section II, Part C, the following 6 AWS specifications for arc welding electrodes, gas welding rods and other filler metals adopted or updated into the latest edition. They are :

  • AWS A5.01M/A5.01:2019 "Welding and Brazing Consumables - Procurement of Filler Materials and Fluxes" as SFA-5.01M/SFA-5.01

  • AWS A5.17/A5.17M:2019 "Specification for Carbon Steel Electrodes and Fluxes for Submerged Arc Welding" as SFA-5.17/SFA-5.17M

  • AWS A5.26/A5.26M:2020 "Specification for Carbon and Low-Alloy Steel Electrodes for Electrogas Welding" as SFA-5.26/SFA-5.26M

  • AWS A5.28/A5.28M:2020 "Specification for Low-Alloy Steel Electrodes and Rods for Gas Shielded Arc Welding" as SFA-5.28/SFA-5.28M

  • AWS A5.34/A5.34M:2018 "Specification for Nickel-Alloy Flux Cored and Metal Cored Welding Electrodes" as SFA-5.34/SFA-5.34M

  • AWS A5.39/A5.39M:2020 "Specification for Flux and Electrode Combinations for Submerged Arc and Electroslag Joining and Surfacing of Stainless Steel and Nickel Alloys" as SFA-5.39/SFA-5.39M and the removed specification is SFA-5.36/SFA-5.36M, since AWS and ANSI have withdrawn A5.36/A5.36M.

In Section II, Part DC & DM, Existing stress lines for Grade 91 have been designated as “Type 1” and new lines have been added for Grade 91 “Type 2” with higher allowable stresses. Tables 6A through 6D containing allowable stresses for ASME BPVC Section IV have been made mandatory. Code Cases 2445-2, 2543, and 2603-1 are incorporated. Also additions and revisions to stress tables and mechanical property tables have been made to support updated specifications.


Major changes to Section III

For Section III, NCA:

  • NCA-1111 revised to include the scope of Division 5 and to provide a reference to Subsection HA to direct the user to general requirements for high temperature reactors.

  • NCA-3461, NCA-3561, NCA-3661, NCA-3684 and NCA-3785 revised to provide consistency and clarification regarding N type Certificate Holders responsibilities.

  • NCA-3862.2 revised to add requirements for N-type certification of materials.

For Section III, NB:

  • Revised NB-3324 to add an additional thickness formula for nonspherical heads in Class 1 construction and NB-3500 revised to define requirements for safety relief devices.

For Section III, NCD:

  • Subsections NC and ND consolidated into one Subsection NCD. The new Subsection NCD contains the requirements for both Class 1 and Class 2 components.

  • Revision to NCD-3531.1 and NCD-3593.1 to add design and test requirements to address Pilot Operated Relief Valves (PORVs) and Pressure Actuated Relief Valves (PARVs).

  • Table NCD-4622.7(b)-1 revised to add rows for socket welds for P-No. 3, P-No. 9A Gr. 1, and P-No. 9B Gr. 1.

  • General note: The rest of Section III was editorially revised to now refer to NCD rather than the individual subsections.

For Section III, NE:

  • Figure NE-2575.2-1 revised to add General Note C to clarify that the sketch shown is typical but is to be used as guide for minimum required coverage of other configurations.

  • Deleted NE-3228.1(a) and NE-4211 revised to align NB/NC/ND/WB/WC/WD-4211. Also NE-6111 revised to clarify that “non-welded access opening covers” are exempted from pressure testing.

For Section III, NF:

  • Various revisions made to Subsection NF and Appendix F to reflect appropriate stress limit conditions identified in the NRC Regulatory Guide 1.130.

  • Revised NF-3322 to be consistent with AISC 360-16 and to align with current industry guidance for pin-connected members.

  • Also, 2 new figures added to provide clarity in application of the dimensional limitations described in the text.

  • New addition in this area is NF-3223.5 to provide additional specificity as to how to determine the critical buckling stress of NF Plate and Shell designs.

For Section III, NG:

  • NG-3211 revised to provide requirements to address buckling of beams and columns.

  • The terms related to stress analysis in NG-3213 updated to be consistent with those in Mandatory Appendix XIII, Design Based on Stress Analysis.

  • NE-3228.1(a) is deleted since the limitation on analytical methods for the remaining stress limits is no longer needed.

  • Revisions to NG-3225, NG-3228, NG-3235 to consolidate and clarify the rules for limit analysis within Subsection NG.

For Section III, Appendices:

  • Revision to XIII-3430 to add a new criterion to explicitly address the ratchet limit due to thermal membrane stress in addition to combined thermal membrane plus bending stress range.

  • Appendix XXVI updated to add new Nonmandatory Supplement E to provide guidance for the pressure design of PE and metallic-to-PE flanged joints.

  • Nonmandatory Appendix B revised to add guidance for additional ultrasonic examination for high alloy metals.

  • New Nonmandatory Appendix MM added to provide guidance on the stress linearization process, based on the stress linearization guidelines in Section VIII, Division 2.

For Section III, Division 2:


  • It is revised to harmonize the material sizing system. All metric bar and coupler sizes referenced within the Code have been revised to maintain the US material sizing system. CC-2438.4.1 and CC-2438.4.2 revised to clarify that qualification test data and test data for permanent corrosion protection material as defined in CC-2438 shall be certified. Table CC-2623.2-1 revised to update strength requirements for studs. CC-2710 and CC-3121 revised to provide clarification on existing requirements.

Section III, Division 3:

  • Subsections WB, WC and WD revised to clarify the prohibition of certain welding processes. Section WC-2129 added to include requirements for fabricated hubbed flanges and Section WC-3263 added to include requirements for Category C Weld Joints for Flat Heads with Hubs. Various Figures and paragraphs revised in WB-3000 to clarify the requirements for the hypothetical fire event.

Section III, Division 5:

  • HHA-3217 revised to update the failure probability calculation to increase the accuracy for fine grained graphite materials. Figure HBB-T-1420-1E revised to update the series of fatigue curves for Grade 91 at elevated temperatures from 700F to 1200F. Appendix HBB-T revised to provide equations for the isochronous stress-strain curves.

General changes for Section IV:

  • Revised the design temperature of plain furnaces in HG-312.1(b).

  • Added requirements to allow for alternative marking of small parts based on BPV Section I, para. PG-106.8.2.

  • Removed the allowable stress tables from Section IV and updated the references to these tables to Section II, Part D.

  • Added New Part HG, Article 8 on Modular Boiler Requirements.

General changes for Section V:

  • Nonmandatory Appendices in Articles 4 and 5 for General Techniques for Straight Beam and Angle Beam Transfer Correction were added and new Article 21 for Pulsed Eddy Current (PEC) Examination were also added.

  • Added a cautionary note to the cover page of each document in Subsection B and new Article 20, Requirements for Computed Tomography Examination were also added.


General changes for Section VII:

  • Change to Section VII is figures were added for a watertube boiler and a package boiler.

General changes for Section VII, Division 1:

  • Added new Mandatory Appendix 47 to prescribe minimum competence requirements for performing design activities, as well as qualification and certification requirements for design personnel

  • Revisions have been made to provide requirements for a Division 1 pressure vessel to be constructed using a cast acrylic shell.

  • New Nonmandatory Appendix UIG-A to serve as a quick reference guide for Manufacturers to use in conjunction with Part UIG were added.

General changes for Section VII, Division 2:

  • Annex 2-B and 2-J are revised to allow engineers to provide Code services, in addition to Certifying Engineers and designers. Also added the educational requirements for engineers and designers and these changes aligns the requirements of Appendix 47 of Section VIII, Division 1.

  • Revised Part 2, para. 2-F.7.1 to include the character size of 4 mm (5/32 in.) for stamping on the nameplate.

  • Para. 3.11.4 revised to permit the use of flux-cored arc welding (FCAW) for Division 2 high alloy construction.

  • ASME STP-PT-074 added as an acceptable method to be followed for evaluating local stresses in shells, formed heads and nozzles.

General changes for Section VIII, Division 3:

  • KM-400.2 and KM-400.2M revised to add new cautionary notes (11) and (12) that involve the chloride stress corrosion cracking of austenitic stainless steels and the corrosion of free-machining stainless steels, respectively.

  • Tables KD-320.1, KD-320.1M, and Figures KD-320.3 and KD- 320.3M revised to update the austenitic stainless-steel fatigue curves.

  • KF-826 revised to update the rules for calculating maximum permissible gaps for welded layered vessel.

  • KE-503 and KT-510 revised to remove requirement that Volumetric Expansion Test be performed separately after Hydrostatic and Acoustic Testing.

  • Appendix L removed and added reference to Section VIII, Division 2, Annex 5-A.

General changes to Section IX:

  • Revised QW-200.4, Table QW-255, QW-403.10 and QW-404.32 concerning GMAW in short-circuit transfer mode.

  • Revised QW-403.6, QW-406.3, QW-407.2, QW-409.1, QW-409.4 and QW-410.9 regarding exemptions for materials not affected by cooling rate when toughness qualification is required.

  • Revised QG-106(a) regarding supervising qualification activities and QG-108 regarding qualifications made to previous editions.

General changes to Section X:

  • Laminate tapers for nozzle attachments revised from 6:1 to 4:1 to align with 4:1 tapers on head/shell and shell/shell joints.

  • Permit the use of a KD factor of 1.0 for all chopped strand mat laminates and laminates consisting of chopped strand mat and woven roving.

  • Adopted the new ASME BPVC Section XIII, Rules for Overpressure Protection.

  • Increased the maximum operating pressure to 2,000 psi.

  • Added reference to Section VIII, Division 3, KD-10 and to make it clear that load sharing pressure parts include not only the metallic liner but the end nozzles as well.

General Changes to Section XI, Division 1:

  • Supplement 15, Qualification Requirements for PWR Reactor Vessel Upper Head Penetrations, to Mandatory Appendix VIII.

  • A new nonmandatory Appendix Y, Crack Growth Rate Curves, to consolidate all existing and future crack growth rate curves used in Section XI.

  • A new nonmandatory Appendix Z, Guide for Buried Piping and Component Inspection Program, to provide guidance for critical attributes which will be addressed in the Owner’s inspection program.

  • IWA-5244 revised to allow one of three pressure test options (i.e. ground surface examination, pressure drop test, or inventory reduction test) for Buried Class 2 and Class 3 components to provide more flexibility to Owners

Section XI, Division 2

  • This was first published in 2019, Figures I-1.1-1 through I-1.1-6 replaced the original Figures I-1.1-1 through I-1.1-7 to fully integrate the flowcharts to convey the RIM process more effectively.

General changes to Section XII:

  • TM-120 was revised to parallel the new wording used in Section VIII, Division 1, UG-10.

  • TP-200 was revised to require that all repairs and alterations to the pressure vessel of a transport tank be performed by organizations holding a National Board “R” Certificate of Authorization.

  • A new mandatory Appendix on Bolted Flange Connections with Ring Gaskets was added.

General changes to Section XIII:

  • This Section is new in 2021 Edition, of Rules for Overpressure Protection. It consolidates and standardizes pressure relief device requirements for all ASME BPVC Sections.


**The content of this article is taken from web open source. The blogs are intended only to give technical knowledge to young engineers. Any engineering calculators, technical equations, and write-ups are only for reference and educational purposes.


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