B31.3 – 2020 Process Piping


Careful application of these B31 codes will help users to comply with applicable regulations within their jurisdictions, while achieving the operational, cost and safety benefits to be gained from the many industry best-practices detailed within these volumes.

Intended for manufacturers, users, constructors, designers, and others concerned with the design, fabrication, assembly, erection, examination, inspection, and testing of piping, plus all potential governing entities.


Product Details

ASME has been defining piping safety since 1922.

ASME B31.3 contains requirements for piping typically found in petroleum refineries; chemical, pharmaceutical, textile, paper, semiconductor, and cryogenic plants; and related processing plants and terminals. It covers materials and components, design, fabrication, assembly, erection, examination, inspection, and testing of piping.

This Code applies to piping for all fluids including:

  1. raw, intermediate, and finished chemicals;
  2. petroleum products;
  3. gas, steam, air and water;
  4. fluidized solids;
  5. refrigerants; and
  6. cryogenic fluids.

Also included is piping that interconnects pieces or stages within a packaged equipment assembly.

Key changes to this revision include:

  • Unlisted Valves (para. 307)
  • Flexibility and Stress Intensification Factors (paras. 319 & 320)
  • Impact Testing (paras. 323.2.2, 323.3.1)
  • Flange Attachment Welds (para. 328.5.2)
  • Heat Treatment (para. 330.1, 331.1)
  • High Pressure Fluid Service Pressure Design (para. K302.3.2)
  • High Pressure Fluid Service Fatigue Analysis (paras. K302.3, K304.8)

B31.3 is one of ASME’s most requested codes. It serves as a companion to ASME’s B31.1 Code on Power Piping as well as to the other codes in ASME’s B31 series. Together, they remain essential references for anyone engaged with piping.