長(chang)輸管(guan)道(dao)（GA）指產地、儲存庫、使用(yong)(yong)單位(wei)間(jian)用(yong)(yong)于輸送(song)商(shang)品介質的壓(ya)力(li)管(guan)道(dao)；公(gong)用(yong)(yong)管(guan)道(dao)（GB）指城(cheng)市或鄉鎮范圍(wei)內的用(yong)(yong)于公(gong)用(yong)(yong)事業(ye)或民(min)用(yong)(yong)的燃氣管(guan)道(dao)和(he)熱力(li)管(guan)道(dao)。

  根據(ju)GB／T 34275《壓力(li)管(guan)(guan)(guan)(guan)道(dao)規(gui)范(fan) 長(chang)輸管(guan)(guan)(guan)(guan)道(dao)》規(gui)定，GA類長(chang)輸管(guan)(guan)(guan)(guan)道(dao)范(fan)圍：①. 設備上的壓力(li)管(guan)(guan)(guan)(guan)道(dao)不在壓力(li)管(guan)(guan)(guan)(guan)道(dao)監(jian)管(guan)(guan)(guan)(guan)范(fan)圍內(nei)(nei)；②. 油(you)氣田站(zhan)場(chang)內(nei)(nei)油(you)氣管(guan)(guan)(guan)(guan)道(dao)按GC類管(guan)(guan)(guan)(guan)道(dao)設計(ji)(ji)、施(shi)工和監(jian)管(guan)(guan)(guan)(guan)：③. 長(chang)輸管(guan)(guan)(guan)(guan)道(dao)站(zhan)場(chang)內(nei)(nei)油(you)氣管(guan)(guan)(guan)(guan)道(dao)可(ke)按GA或GC類管(guan)(guan)(guan)(guan)道(dao)設計(ji)(ji)、施(shi)工，按GC類管(guan)(guan)(guan)(guan)道(dao)監(jian)管(guan)(guan)(guan)(guan)；④長(chang)輸管(guan)(guan)(guan)(guan)道(dao)末(mo)站(zhan)至工廠(chang)或城市燃氣門站(zhan)的管(guan)(guan)(guan)(guan)道(dao)按GA類管(guan)(guan)(guan)(guan)道(dao)設計(ji)(ji)、施(shi)工和監(jian)管(guan)(guan)(guan)(guan)；⑤廠(chang)際油(you)氣管(guan)(guan)(guan)(guan)道(dao)可(ke)按GA或GC類管(guan)(guan)(guan)(guan)道(dao)設計(ji)(ji)、施(shi)工。見圖8-1所(suo)示。

  根據GB／T 38942《壓力管道(dao)規范(fan)公用(yong)管道(dao)》規定的GB類公用(yong)管道(dao)范(fan)圍(wei)如下。

一、包(bao)括

  ①. 城鎮燃(ran)氣管道GB1：由門(men)站、儲配站、各類氣源(yuan)廠站等燃(ran)氣廠站至用(yong)戶(hu)之(zhi)間或廠站之(zhi)間公(gong)用(yong)性質的燃(ran)氣管道及附屬設(she)施(shi)，附屬設(she)施(shi)包括線路閥室、調壓站（含調壓箱）、凝水缸等，見圖(tu)8-2所示。

  分輸站至門站之(zhi)間的(de)燃氣(qi)管道應(ying)執(zhi)行GA類管道規范。當敷設(she)在城市建成(cheng)區時，可按GB1標準執(zhi)行。

  ②. 城鎮(zhen)熱(re)(re)力(li)管道：由熱(re)(re)源出(chu)口分界點至熱(re)(re)用戶（民用或工業）進口分界點之間，敷設(she)在城鎮(zhen)范圍內(nei)的蒸(zheng)(zheng)汽管道和熱(re)(re)水管道及其附屬設(she)施，見圖8-3所示。其中(zhong)蒸(zheng)(zheng)汽介質(zhi)設(she)計壓(ya)力(li)小于(yu)(yu)(yu)或等于(yu)(yu)(yu)2.5MPa，設(she)計溫度小于(yu)(yu)(yu)或等于(yu)(yu)(yu)350℃；熱(re)(re)水介質(zhi)設(she)計壓(ya)力(li)小于(yu)(yu)(yu)或等于(yu)(yu)(yu)2.5MPa，設(she)計溫度小于(yu)(yu)(yu)或等于(yu)(yu)(yu)200℃。

二、不包括

  ①. 燃(ran)氣系統(tong)中(zhong)廠站(zhan)(zhan)內（調壓站(zhan)(zhan)除外）的燃(ran)氣管道和熱(re)力系統(tong)中(zhong)廠站(zhan)(zhan)內（熱(re)力站(zhan)(zhan)和熱(re)分配(pei)站(zhan)(zhan)除外）的熱(re)力管道。

  ②. 工(gong)業用(yong)戶內(nei)部(bu)燃氣和熱(re)力(li)管(guan)道（以(yi)廠界劃分(fen)）。

  ③. 商業和居(ju)民用(yong)戶內部燃(ran)氣管(guan)道（以用(yong)戶引入管(guan)閥(fa)門為(wei)界(jie)）和熱力管(guan)道（以熱力人口為(wei)界(jie)）。

  ④. 燃氣(qi)和熱力設備內部(bu)管道。