This document specifies the characteristics of the fitness for purpose of polybutene-1 (PB-1) 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 design pressures and temperatures according to the class of application (see ISO15876‑1). The designation polybutene is used together with the abbreviation PB throughout this document. This document covers a range of service conditions (application classes) and design pressure classes. For values of TD, Tmax and Tmal in excess of those in ISO15876‑1:2017, Table1, this document does not apply. NOTE 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 document. In conjunction with the other parts of ISO15876, it is applicable to PB pipes, fittings, their joints and to joints with components of other plastics and non-plastics materials intended to be used for hot and cold water installations.