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 ASMEâ??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.