ISO 1452-4:2009 specifies the characteristics of valves made from unplasticized poly(vinyl chloride) (PVC‑U) for piping systems intended for water supply and for buried and above-ground drainage and sewerage under pressure. It also specifies the test parameters for the test methods referred to. In conjunction with ISO 1452-1, ISO 1452-2, ISO 1452-3 and ISO 1452-5 it is applicable to PVC‑U valves with components of PVC-U, other plastics and non-plastics materials intended to be used for the following: - water mains and services buried in ground; - conveyance of water above ground for both outside and inside buildings; - buried and above-ground drainage and sewerage under pressure. It is applicable to valves in piping systems intended for the supply of water under pressure up to and including 25 °C (cold water) intended for human consumption and for general purposes as well as for waste water under pressure. It is also applicable to valves for the conveyance of water and waste water up to and including 45 °C.