ASME B31.5 covers refrigerant, heat transfer components, and secondary coolant piping for temperatures as low as -320°F (-196°C), whether erected on the premises or factory assembled. Users are advised that other piping Code Sections may provide requirements for refrigeration piping in their respective jurisdictions.

This Code does not apply to any self-contained or unit systems subject to the requirements of Underwriters Laboratories or other nationally recognized testing laboratory. It also does not apply to water piping; piping designed for external or internal gage pressure not exceeding 15 psi (105 kPa) regardless of size; or pressure vessels, compressors, or pumps. However, B31.5 does include all connecting refrigerant and secondary coolant piping starting at the first joint adjacent to such apparatus.

Key changes to this edition include revisions to sections on flange facings, bolting for cast iron flanges, and grey iron and malleable iron materials.

B31.5 prescribes comprehensive solutions for materials, design, fabrication, assembly, erection, testing and inspection. It also 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.