對(dui)于(yu)一些蒸汽和熱水管(guan)(guan)(guan)(guan)(guan)道可(ke)(ke)以(yi)采(cai)用(yong)直(zhi)埋的(de)布置方(fang)式，相應的(de)管(guan)(guan)(guan)(guan)(guan)道材(cai)料可(ke)(ke)選用(yong)鋼(gang)套鋼(gang)管(guan)(guan)(guan)(guan)(guan)及管(guan)(guan)(guan)(guan)(guan)件、高密(mi)度聚乙(yi)烯外護(hu)管(guan)(guan)(guan)(guan)(guan)保溫管(guan)(guan)(guan)(guan)(guan)及管(guan)(guan)(guan)(guan)(guan)件等材(cai)料。如圖4-80所示，這種材(cai)料既解(jie)決了管(guan)(guan)(guan)(guan)(guan)子(zi)熱膨脹問題(ti)(ti)，也解(jie)決了隔熱層的(de)防(fang)水等問題(ti)(ti)。詳(xiang)細講述見(jian)《工業管(guan)(guan)(guan)(guan)(guan)道配管(guan)(guan)(guan)(guan)(guan)設計與工程應用(yong)》《管(guan)(guan)(guan)(guan)(guan)道器材(cai)選用(yong)與工程應用(yong)》。

  有(you)關標準規范包括：GB／T 29047《高密(mi)度(du)聚乙烯外(wai)護(hu)管(guan)硬(ying)質聚氨酯泡(pao)沫塑料預(yu)(yu)制直(zhi)埋保溫(wen)(wen)管(guan)及管(guan)件(jian)》［適用(yong)于輸送介質溫(wen)(wen)度(du)（長期運行(xing)溫(wen)(wen)度(du)）不(bu)高于120℃，偶(ou)然峰值(zhi)溫(wen)(wen)度(du)不(bu)高于140℃的預(yu)(yu)制直(zhi)埋保溫(wen)(wen)管(guan)、保溫(wen)(wen)管(guan)件(jian)及保溫(wen)(wen)接頭(tou)］

  EN 253《用于區域供(gong)熱熱水管網一由工作(zuo)鋼管、聚氨酯保(bao)溫(wen)層和(he)高(gao)密(mi)度聚乙烯外護(hu)管組成的預(yu)制直埋(mai)保(bao)溫(wen)管》；

  EN 448《用(yong)于區域供熱熱水管(guan)(guan)網一由工作鋼管(guan)(guan)、聚(ju)氨酯保溫層(ceng)和(he)高密度聚(ju)乙烯(xi)外護管(guan)(guan)組(zu)成的預制直埋保溫管(guan)(guan)件》；

  EN 489《用(yong)于區域供熱(re)熱(re)水管(guan)(guan)網(wang)一由工(gong)作鋼管(guan)(guan)、聚氨酯(zhi)保溫層和高(gao)密度聚乙烯外護管(guan)(guan)組成的(de)預制直埋保溫管(guan)(guan)道接頭》。

  有(you)的(de)(de)壓力(li)管(guan)道(dao)設(she)計人員用普通的(de)(de)隔熱(re)保溫管(guan)道(dao)直埋(mai)，會導(dao)致(zhi)隔熱(re)層(ceng)失效。有(you)的(de)(de)壓力(li)管(guan)道(dao)設(she)計人員做地溝，在地溝內按地上管(guan)道(dao)布置設(she)計蒸(zheng)汽或熱(re)水管(guan)道(dao)，不(bu)如直埋(mai)布置設(she)計成本更(geng)低一些。