HG 20225《化工金屬管(guan)(guan)道(dao)(dao)(dao)(dao)工程施(shi)工及驗收規范》規定化工行業金屬管(guan)(guan)道(dao)(dao)(dao)(dao)應按管(guan)(guan)道(dao)(dao)(dao)(dao)所輸送(song)(song)的(de)介(jie)質(zhi)(zhi)分為(wei)(wei)四類(lei)(lei)(lei)：A類(lei)(lei)(lei)為(wei)(wei)輸送(song)(song)劇毒(du)介(jie)質(zhi)(zhi)的(de)管(guan)(guan)道(dao)(dao)(dao)(dao)；B類(lei)(lei)(lei)為(wei)(wei)輸送(song)(song)可燃(ran)介(jie)質(zhi)(zhi)或(huo)有毒(du)介(jie)質(zhi)(zhi)的(de)管(guan)(guan)道(dao)(dao)(dao)(dao)；C類(lei)(lei)(lei)、D類(lei)(lei)(lei)為(wei)(wei)輸送(song)(song)非可燃(ran)介(jie)質(zhi)(zhi)、無毒(du)介(jie)質(zhi)(zhi)的(de)管(guan)(guan)道(dao)(dao)(dao)(dao)。其中設計壓力p≤1MPa，且(qie)設計溫度為(wei)(wei)-29～186℃的(de)管(guan)(guan)道(dao)(dao)(dao)(dao)為(wei)(wei)D類(lei)(lei)(lei)管(guan)(guan)道(dao)(dao)(dao)(dao)。

   注意(yi)：混(hun)合物(wu)料應以(yi)其主導物(wu)料作(zuo)為(wei)分級依據。常見(jian)劇毒(du)(du)介(jie)質(zhi)(zhi)、可燃介(jie)質(zhi)(zhi)或有毒(du)(du)介(jie)質(zhi)(zhi)，請(qing)參考《化(hua)工金屬管道工程(cheng)施工及(ji)驗收(shou)規范》的(de)附錄(lu)。