ISO 15875-5:2003 specifies the characteristics of the fitness for purpose of crosslinked polyethylene (PE-X) piping systems intended to be used for hot and cold water installations, within buildings, for the conveyance of water which may or may not be intended for human consumption (domestic systems) and for heating systems, under design pressures and temperatures appropriate to the class of application. It covers a range of service conditions (classes of application) and design pressure classes. It does not apply if the values of the design temperature, maximum design temperature and malfunction temperature are in excess of those given in ISO 15875-1. It also specifies the test parameters for the test methods referred to in the standard. In conjunction with the other parts of ISO 15875, it is applicable to PE-X pipes, fittings and their joints, including joints with components of other plastics and non-plastics materials intended to be used for hot and cold water installations.