HG 20225《化(hua)工金屬管(guan)(guan)(guan)道(dao)工程施工及驗收規范(fan)》規定(ding)化(hua)工行業金屬管(guan)(guan)(guan)道(dao)應按管(guan)(guan)(guan)道(dao)所輸(shu)送(song)的介(jie)(jie)質(zhi)(zhi)分為四類(lei)：A類(lei)為輸(shu)送(song)劇毒介(jie)(jie)質(zhi)(zhi)的管(guan)(guan)(guan)道(dao)；B類(lei)為輸(shu)送(song)可燃(ran)介(jie)(jie)質(zhi)(zhi)或有毒介(jie)(jie)質(zhi)(zhi)的管(guan)(guan)(guan)道(dao)；C類(lei)、D類(lei)為輸(shu)送(song)非可燃(ran)介(jie)(jie)質(zhi)(zhi)、無毒介(jie)(jie)質(zhi)(zhi)的管(guan)(guan)(guan)道(dao)。其(qi)中(zhong)設(she)計壓(ya)力p≤1MPa，且(qie)設(she)計溫度為-29～186℃的管(guan)(guan)(guan)道(dao)為D類(lei)管(guan)(guan)(guan)道(dao)。

   注意：混(hun)合物料(liao)應以其主導物料(liao)作為分級依據。常見(jian)劇毒介(jie)(jie)質(zhi)、可燃介(jie)(jie)質(zhi)或有(you)毒介(jie)(jie)質(zhi)，請參考《化工(gong)金屬管道工(gong)程施工(gong)及驗收規范(fan)》的附錄。