ASME B31.3 Process Piping: Changes in the 2024 Edition

The new edition of the ASME B31.3 Process Piping Code is scheduled to be issued December 27, 2024. As usual, there are many clarifications, updated references to codes and standards, updates to basic allowable stresses, and additional listed materials. These types of changes are not described here.

Note that many figures and tables have been redesignated to comply with the current editorial style guidelines.

The most significant substantive changes are:

Hoses (Para. F306.7)

• Added a recommendation to consult the Energy Institute publication Guidelines for the Management of Flexible Hose Assemblies

Sustained Stress Indices (Para. 320.1)

• Changed from using 0.75i and 1.0 as default values in the absence of more applicable data for sustained stress indices to referring to ASME B31J for default values

Listed Fittings (Table 326.1)

• Added press-connect fittings (ASME B16.51 & ASTM F3226­)
• Added globe valves (API 623)
• Added high-pressure butterfly valves (MSS SP-68)
• Deleted metal hose standard BS 6501-1

Backing Gas (Para. 328.5.1)

• Stated that acceptable level of discoloration should be described in the engineering design

Bolt Tightening (Para. 335.2.2)

• Stated that the bolt stress is not limited to the allowable stress when tightening bolts

Surfaces on Pressure-Containing Components Where Attachment Welds Have Been Removed

• Revised examination requirements (para. 341.5) and acceptance criteria (para. 341.3.2)

Leak Testing Mechanical Joints (Para. 345.2.3)

• Preciously permitted only for flanged joints, and for threaded and tubing joints used to connect instruments, the 2024 edition permits all mechanical joints that have been leak tested to be taken apart and reassembled without having to be subjected to an additional leak test.

Joints in Thermoplastic Piping

• Added additional acceptable procedures for:
• Solvent Cemented Joints (para. A328.5.3)
• Heat Fusion Joints (para. A328.5.4)
• Electrofusion Joints (para. A328.5.5)

Examination of Branch Connection Fitting to Header Welds (Para. M341.4)

• Removed the requirement that branch connection fitting to header welds be radiographically or ultrasonically examined in Category M Fluid Service

Written Report (Para. K300)

• Added specific requirements for the designer to report to the owner

Allowable Stresses (Para. K302.3.2, Appendix K)

• Changed the basis for allowable stresses in High Pressure Piping to align ASME B31.3 Chapter IX with the 2023 edition of ASME BPV Section VIII Division 3

Lower Temperature Limit for ASTM A105 Flanges (Para. F323.2.2)

• Recommended that the designer consider additional material requirements for ASTM A105, Class 150 and 300 weld neck flanges for temperatures colder than -18°C (0°F)

European Pressure Equipment Directive (Para. N301)

• Recommendations regarding the use of ASME B31.3 in jurisdictions governed by the Pressure Equipment Directive were updated and expanded

If you have questions about ASME B31.3 or are looking for support with your piping design needs, contact Becht today—our experts are here to help. You can also register for our in-person or virtual ASME B31.3 Process Piping – Design, Construction, and Mechanical Integrity training course, designed to provide comprehensive insights into B31.3 requirements and practical applications.