HG 20225《化(hua)工(gong)(gong)金屬(shu)管(guan)(guan)道工(gong)(gong)程施工(gong)(gong)及驗收規范》規定化(hua)工(gong)(gong)行業金屬(shu)管(guan)(guan)道應按管(guan)(guan)道所輸送(song)的(de)介質(zhi)(zhi)分為(wei)四類(lei)(lei)(lei)：A類(lei)(lei)(lei)為(wei)輸送(song)劇毒(du)介質(zhi)(zhi)的(de)管(guan)(guan)道；B類(lei)(lei)(lei)為(wei)輸送(song)可(ke)燃(ran)介質(zhi)(zhi)或有毒(du)介質(zhi)(zhi)的(de)管(guan)(guan)道；C類(lei)(lei)(lei)、D類(lei)(lei)(lei)為(wei)輸送(song)非(fei)可(ke)燃(ran)介質(zhi)(zhi)、無(wu)毒(du)介質(zhi)(zhi)的(de)管(guan)(guan)道。其中設計壓力p≤1MPa，且設計溫度為(wei)-29～186℃的(de)管(guan)(guan)道為(wei)D類(lei)(lei)(lei)管(guan)(guan)道。

   注(zhu)意：混合物料應以(yi)其主導物料作為分級依據。常見劇毒介質(zhi)、可燃介質(zhi)或有毒介質(zhi)，請參考《化工金屬管道工程(cheng)施工及(ji)驗收(shou)規范》的附錄(lu)。