HG 20225《化工(gong)金屬(shu)管(guan)(guan)道(dao)(dao)工(gong)程施工(gong)及(ji)驗收規(gui)范》規(gui)定化工(gong)行業金屬(shu)管(guan)(guan)道(dao)(dao)應按管(guan)(guan)道(dao)(dao)所(suo)輸送(song)的介(jie)質(zhi)分為(wei)(wei)四(si)類：A類為(wei)(wei)輸送(song)劇毒介(jie)質(zhi)的管(guan)(guan)道(dao)(dao)；B類為(wei)(wei)輸送(song)可(ke)燃(ran)介(jie)質(zhi)或有毒介(jie)質(zhi)的管(guan)(guan)道(dao)(dao)；C類、D類為(wei)(wei)輸送(song)非可(ke)燃(ran)介(jie)質(zhi)、無毒介(jie)質(zhi)的管(guan)(guan)道(dao)(dao)。其中設計(ji)壓力(li)p≤1MPa，且(qie)設計(ji)溫度為(wei)(wei)-29～186℃的管(guan)(guan)道(dao)(dao)為(wei)(wei)D類管(guan)(guan)道(dao)(dao)。

   注意：混(hun)合物(wu)料應以其(qi)主導(dao)物(wu)料作為分級依據。常(chang)見(jian)劇毒介質(zhi)、可燃(ran)介質(zhi)或(huo)有(you)毒介質(zhi)，請參考《化工(gong)金屬(shu)管(guan)道工(gong)程(cheng)施工(gong)及驗收規(gui)范(fan)》的附(fu)錄。