HG 20225《化工(gong)金(jin)屬管道(dao)工(gong)程(cheng)施工(gong)及(ji)驗收規(gui)范》規(gui)定化工(gong)行業金(jin)屬管道(dao)應按管道(dao)所輸(shu)送(song)(song)的介質(zhi)(zhi)(zhi)分為(wei)四類(lei)(lei)：A類(lei)(lei)為(wei)輸(shu)送(song)(song)劇(ju)毒(du)介質(zhi)(zhi)(zhi)的管道(dao)；B類(lei)(lei)為(wei)輸(shu)送(song)(song)可燃介質(zhi)(zhi)(zhi)或有毒(du)介質(zhi)(zhi)(zhi)的管道(dao)；C類(lei)(lei)、D類(lei)(lei)為(wei)輸(shu)送(song)(song)非可燃介質(zhi)(zhi)(zhi)、無毒(du)介質(zhi)(zhi)(zhi)的管道(dao)。其(qi)中設計壓力p≤1MPa，且設計溫(wen)度為(wei)-29～186℃的管道(dao)為(wei)D類(lei)(lei)管道(dao)。

   注意：混(hun)合物料應以其(qi)主(zhu)導物料作(zuo)為分級(ji)依據。常(chang)見(jian)劇(ju)毒(du)(du)介質、可燃(ran)介質或有毒(du)(du)介質，請(qing)參考(kao)《化工(gong)(gong)金屬管道工(gong)(gong)程施工(gong)(gong)及驗收(shou)規范》的附錄。