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: • Category M fluid service definition revised • Revision to the equation for allowable stress range • Thermowell design • Use of cold spring • Impact testing of carbon steels • Installation of Weldolets • Preheat requirements • Heat treatment requirements • Qualification of examination personnel • Acceptance criteria for liquid penetrant an magnetic particle examination • Leak test for high pressure piping • Alternative rules for evaluation of stress range 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.