EN 253:2019+A1:2023 区域供热管道 用于直埋热水网络的粘合单管系统 工厂制造的钢制服务管、聚氨酯隔热材料和聚乙烯套管的管道组件
District heating pipes - Bonded single pipe systems for directly buried hot water networks - Factory made pipe assembly of steel service pipe, polyurethane thermal insulation and a casing of polyethylene