ISO 14531-2:2004 specifies the physical properties and mechanical performance requirements of crosslinked polyethylene (PE-X) and polyethylene (PE) socket, saddle and spigot fittings for the connection by socket or saddle heat-fusion jointing techniques of PE-X pipes manufactured in accordance with ISO 14531-1. In addition, it lays down dimensional requirements and specifies some general material properties (including chemical resistance) together with a classification scheme for PE-X fitting base materials produced in the form of pipe.

When used in conjunction with the other parts of ISO 14531, it provides the basis for the design, manufacture and installation of PE-X piping systems (PE-X pipes, PE-X fusion fittings and mechanical fittings) for the supply of category D and category E gaseous fuels.