BS EN 488:2015 区域供暖管道.直埋式热水供应网用预先隔热包覆的管道系统.聚氨基甲酸乙酯热绝缘和聚乙烯外覆层钢管用钢阀门组件
District heating pipes. Preinsulated bonded pipe systems for directly buried hot water networks. Steel valve assembly for steel service pipes, polyurethane thermal insulation and outer casing of polyethylene