This part ISO 15874 specifies the requirements of pipes made from polypropylene (PP) for piping systems intended to be used for hot and cold water installations within buildings for the conveyance of water whether or not intended for human consumption (domestic systems) and for heating systems under operating pressures and temperatures appropriate to the class of application (see ISO 15874-1:2012, Table 1). This part of ISO 15874 covers a range of service conditions (application classes), design pressures and pipe dimension classes. For values of TD, Tmax and Tmal in excess of those in Table 1 of ISO 15874-1 do not apply. NOTE 1 It is the responsibility of the purchaser or specifier to make the appropriate selections from these aspects, taking into account their particular requirements and any relevant national regulations and installation practices or codes. It also specifies the test parameters for the test methods referred to in this part of ISO 15874. In conjunction with the other parts of ISO 15874, this part of ISO 15874 is applicable to PP pipes, their joints and to joints with components of PP, other plastics and non-plastics materials intended to be used for hot and cold water installations. It is applicable to pipes with or without (a) barrier layer(s). NOTE 2 In the case of plastics pipes provided with a thin barrier layer, e.g. to prevent or greatly diminish the diffusion of gases and the transmission of light into or through the pipe wall, the design stress requirements are totally met by the base polymer (PP).