ASME B31.5, Refrigeration Piping, covers piping systems for refrigerant and brine at temperatures as low as -196°C (-320″F), whether erected on the premises or factory assembled. Coverage does not include (1) self-contained or unit refrigeration systems subject to requirements of Underwriters Laboratories or any other nationally recognized testing laboratory, (2) water piping, or (3) piping designed for external or
internal pressure not exceeding 103 kPa (15 psig) regardless of size. See PIPE WELDING.

X