HG 20225《化工(gong)(gong)金屬管(guan)(guan)道工(gong)(gong)程施工(gong)(gong)及驗收規范》規定化工(gong)(gong)行業金屬管(guan)(guan)道應按管(guan)(guan)道所輸(shu)送的介質(zhi)(zhi)(zhi)分為(wei)四(si)類：A類為(wei)輸(shu)送劇(ju)毒介質(zhi)(zhi)(zhi)的管(guan)(guan)道；B類為(wei)輸(shu)送可(ke)燃(ran)介質(zhi)(zhi)(zhi)或有毒介質(zhi)(zhi)(zhi)的管(guan)(guan)道；C類、D類為(wei)輸(shu)送非可(ke)燃(ran)介質(zhi)(zhi)(zhi)、無毒介質(zhi)(zhi)(zhi)的管(guan)(guan)道。其(qi)中(zhong)設(she)計(ji)壓力p≤1MPa，且設(she)計(ji)溫度為(wei)-29～186℃的管(guan)(guan)道為(wei)D類管(guan)(guan)道。

   注意：混合(he)物(wu)(wu)料(liao)應以其主導物(wu)(wu)料(liao)作為分級依據(ju)。常見劇毒(du)介(jie)質(zhi)(zhi)、可燃介(jie)質(zhi)(zhi)或有毒(du)介(jie)質(zhi)(zhi)，請參(can)考《化(hua)工(gong)(gong)金屬管道工(gong)(gong)程施工(gong)(gong)及(ji)驗收(shou)規范(fan)》的附錄(lu)。