GB/T 29047-2021高密度聚乙烯外护管硬质聚氨酯泡沫塑料预制直埋保温管及管件标准
英文:Prefabricated directly buried insulating pipes and fittings with polyurethane foamed-plastics and high density polyet...
英文:Prefabricated directly buried insulating pipes and fittings with polyurethane foamed-plastics and high density polyet...