This part of PS 106 specifies the general aspects of multilayer piping systems intended to be used for hot and cold water installations inside buildings for the conveyance of water — whether or not the water is
intended for human consumption (domestic systems) or heating systems — under specified design pressures and temperatures appropriate to the class of application (see Table 1).
PS 106 is a reference product standard (see 3.4.3). It is applicable to multilayer pipes, fittings, their joints, and also to joints with components made of other plastics and non-plastics materials intended to be used for
hot and cold water installations. This part of PS 106 is intended for use only in conjunction with all the other parts of PS 106.
PS 106 applies only to multilayer pipes with their inner layer made of plastics.

It covers a range of service conditions (application classes) and design pressures. It is not applicable for values of design temperature, TD, maximum design temperature, Tmax, and malfunction temperature, Tmal, in
excess of those in Table 1.

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.

The polymeric materials used for the stress-designed layers are the following: polybutylene (PB), polyethylene of raised temperature resistance (PE-RT), crosslinked polyethylene (PE-X), polypropylene (PP) and
chlorinated poly(vinyl chloride) (PVC-C). The PE-X used shall be fully crosslinked