Plastics piping systems for water supply and for buried and above-ground drainage and sewerage under pressure - Unplasticized poly(vinyl chloride) (PVC-U) - Part 4: Valves (ISO 1452-4:2009)
供水和埋地及地上压力排水和污水用塑料管道系统.未增塑聚氯乙烯(PVC-U).第4部分:阀门(ISO 1452-4-2009)