①. 由于各國管件標準化程度不同，分支管連接方式及管件的選擇也不盡相同。一般情況下，支管連接多采用成形支管連接件、焊接的引出口連接件以及支管直接焊接在主管上等連接形式。值得注意的是選用支管直接焊接在主管上這一種連接形式，要核算管子是否需要補強。補強方法參見SH 3059《石油化工管道設計器材選用通則》、GB50316《工業金屬管道設計規范》的規定。

 ②. 支管連(lian)接件的選擇

   a. 主(zhu)要根據管(guan)(guan)道(dao)的設計(ji)(ji)溫度、設計(ji)(ji)壓(ya)力、腐蝕余量等設計(ji)(ji)條件(jian)確(que)定的。分(fen)(fen)支(zhi)的方(fang)法(fa)：對于(yu)低壓(ya)大(da)直(zhi)徑(jing)管(guan)(guan)則直(zhi)接把分(fen)(fen)支(zhi)管(guan)(guan)焊于(yu)主(zhu)管(guan)(guan)上(shang)，另外多數是(shi)利(li)用分(fen)(fen)支(zhi)管(guan)(guan)件(jian)進行分(fen)(fen)支(zhi)。

   b. 當(dang)(dang)從主(zhu)管(guan)(guan)(guan)(guan)(guan)引(yin)出支(zhi)管(guan)(guan)(guan)(guan)(guan)時，支(zhi)管(guan)(guan)(guan)(guan)(guan)直(zhi)徑(jing)與主(zhu)管(guan)(guan)(guan)(guan)(guan)直(zhi)徑(jing)的(de)比值大于(yu)(yu)(yu)等于(yu)(yu)(yu)0.5時，采用(yong)異徑(jing)三通(tong)或(huo)等徑(jing)三通(tong)，當(dang)(dang)主(zhu)支(zhi)管(guan)(guan)(guan)(guan)(guan)為等徑(jing)時，應(ying)采用(yong)三通(tong)。GB50316 規定：公稱壓力大于(yu)(yu)(yu)或(huo)等于(yu)(yu)(yu)10MPa的(de)管(guan)(guan)(guan)(guan)(guan)道，主(zhu)支(zhi)管(guan)(guan)(guan)(guan)(guan)為異徑(jing)時，不(bu)宜采用(yong)焊接支(zhi)管(guan)(guan)(guan)(guan)(guan)，宜采用(yong)三通(tong)或(huo)在主(zhu)管(guan)(guan)(guan)(guan)(guan)上開孔并(bing)焊接支(zhi)管(guan)(guan)(guan)(guan)(guan)臺(tai)。當(dang)(dang)主(zhu)管(guan)(guan)(guan)(guan)(guan)直(zhi)徑(jing)大于(yu)(yu)(yu)DN65而支(zhi)管(guan)(guan)(guan)(guan)(guan)直(zhi)徑(jing)為DN40及以下(xia)時，根據(ju)設計壓力的(de)大小，采用(yong)支(zhi)管(guan)(guan)(guan)(guan)(guan)臺(tai)或(huo)半管(guan)(guan)(guan)(guan)(guan)接頭。

   c. 主管(guan)(guan)(guan)(guan)(guan)直(zhi)(zhi)徑(jing)(jing)(jing)(jing)小(xiao)于(yu)(yu)(yu)(yu)(yu)(yu)DN50時，支管(guan)(guan)(guan)(guan)(guan)小(xiao)于(yu)(yu)(yu)(yu)(yu)(yu)主管(guan)(guan)(guan)(guan)(guan)，則(ze)用(yong)異徑(jing)(jing)(jing)(jing)三(san)(san)通(tong)或(huo)等徑(jing)(jing)(jing)(jing)三(san)(san)通(tong)加(jia)異徑(jing)(jing)(jing)(jing)短管(guan)(guan)(guan)(guan)(guan)。設計壓力等于(yu)(yu)(yu)(yu)(yu)(yu)或(huo)大于(yu)(yu)(yu)(yu)(yu)(yu)2.0MPa、設計溫度(du)超過(guo)250℃以及支管(guan)(guan)(guan)(guan)(guan)與主管(guan)(guan)(guan)(guan)(guan)公稱直(zhi)(zhi)徑(jing)(jing)(jing)(jing)之比大于(yu)(yu)(yu)(yu)(yu)(yu)0.8，或(huo)承(cheng)受機械(xie)振動、壓力脈動和溫度(du)急劇(ju)變化的管(guan)(guan)(guan)(guan)(guan)道分支，應(ying)采用(yong)等徑(jing)(jing)(jing)(jing)異徑(jing)(jing)(jing)(jing)三(san)(san)通(tong)；公稱直(zhi)(zhi)徑(jing)(jing)(jing)(jing)小(xiao)于(yu)(yu)(yu)(yu)(yu)(yu)或(huo)等于(yu)(yu)(yu)(yu)(yu)(yu)40mm的管(guan)(guan)(guan)(guan)(guan)道，應(ying)采用(yong)承(cheng)插焊(han)(han)（或(huo)螺紋(wen)）鍛制三(san)(san)通(tong)；公稱直(zhi)(zhi)徑(jing)(jing)(jing)(jing)等于(yu)(yu)(yu)(yu)(yu)(yu)或(huo)大于(yu)(yu)(yu)(yu)(yu)(yu)50mm的管(guan)(guan)(guan)(guan)(guan)道，應(ying)采用(yong)對(dui)焊(han)(han)三(san)(san)通(tong)、對(dui)焊(han)(han)加(jia)強管(guan)(guan)(guan)(guan)(guan)接(jie)頭(tou)(tou)(tou)（對(dui)焊(han)(han)支管(guan)(guan)(guan)(guan)(guan)臺(tai)）或(huo)嵌入式(shi)（鞍型(xing)）支管(guan)(guan)(guan)(guan)(guan)接(jie)頭(tou)(tou)(tou)。支管(guan)(guan)(guan)(guan)(guan)通(tong)過(guo)加(jia)強管(guan)(guan)(guan)(guan)(guan)接(jie)頭(tou)(tou)(tou)（支管(guan)(guan)(guan)(guan)(guan)臺(tai)）與主管(guan)(guan)(guan)(guan)(guan)連接(jie)是指將一個螺紋(wen)、承(cheng)插焊(han)(han)或(huo)對(dui)焊(han)(han)的管(guan)(guan)(guan)(guan)(guan)接(jie)頭(tou)(tou)(tou)或(huo)半(ban)管(guan)(guan)(guan)(guan)(guan)接(jie)頭(tou)(tou)(tou)（支管(guan)(guan)(guan)(guan)(guan)臺(tai)）直(zhi)(zhi)接(jie)焊(han)(han)于(yu)(yu)(yu)(yu)(yu)(yu)主管(guan)(guan)(guan)(guan)(guan)上而制成(cheng)，螺紋(wen)、承(cheng)插焊(han)(han)支管(guan)(guan)(guan)(guan)(guan)臺(tai)用(yong)于(yu)(yu)(yu)(yu)(yu)(yu)直(zhi)(zhi)徑(jing)(jing)(jing)(jing)小(xiao)于(yu)(yu)(yu)(yu)(yu)(yu)等于(yu)(yu)(yu)(yu)(yu)(yu)DN40（NPS1/2）的支管(guan)(guan)(guan)(guan)(guan)連接(jie)。螺紋(wen)、承(cheng)插焊(han)(han)支管(guan)(guan)(guan)(guan)(guan)臺(tai)在任何情況下(xia)其額定等級應(ying)大于(yu)(yu)(yu)(yu)(yu)(yu)等于(yu)(yu)(yu)(yu)(yu)(yu)20001b。

   d. 其(qi)他(ta)支(zhi)(zhi)管(guan)連(lian)(lian)接(jie)(jie)可(ke)用(yong)直(zhi)接(jie)(jie)焊(han)接(jie)(jie)，但必須經校核后明確是否增加補強。直(zhi)接(jie)(jie)焊(han)接(jie)(jie)在主管(guan)上的(de)(de)支(zhi)(zhi)管(guan)連(lian)(lian)接(jie)(jie)，不宜用(yong)于有機械振動、壓力脈動和溫(wen)度急劇變化(hua)的(de)(de)部(bu)位及設計溫(wen)度超(chao)過425℃的(de)(de)管(guan)道，當支(zhi)(zhi)管(guan)連(lian)(lian)接(jie)(jie)處承(cheng)受由于支(zhi)(zhi)管(guan)熱變形、外載(zai)荷及支(zhi)(zhi)架位移等(deng)引起的(de)(de)應力時，應對附(fu)加載(zai)荷在支(zhi)(zhi)管(guan)連(lian)(lian)接(jie)(jie)處產(chan)生的(de)(de)影響進行分析并采取必要的(de)(de)加強措施。

   e. 實際設計過程中，主要(yao)依據管(guan)(guan)(guan)(guan)(guan)(guan)(guan)道等級中已經確(que)定的(de)(de)(de)法蘭壓(ya)力(li)(li)等級或(huo)公稱(cheng)壓(ya)力(li)(li)（PN）來選用(yong)支(zhi)(zhi)管(guan)(guan)(guan)(guan)(guan)(guan)(guan)連(lian)接(jie)件(jian)(jian)(jian)(jian)。一般情況下，當法蘭的(de)(de)(de)公稱(cheng)壓(ya)力(li)(li)PN≤2.5MPa時，支(zhi)(zhi)管(guan)(guan)(guan)(guan)(guan)(guan)(guan)直接(jie)焊(han)(han)(han)(han)接(jie)在(zai)主管(guan)(guan)(guan)(guan)(guan)(guan)(guan)上；當PN≥4.0MPa時，則(ze)根(gen)據主管(guan)(guan)(guan)(guan)(guan)(guan)(guan)支(zhi)(zhi)管(guan)(guan)(guan)(guan)(guan)(guan)(guan)公稱(cheng)直徑(jing)的(de)(de)(de)不同按對(dui)(dui)焊(han)(han)(han)(han)三通、對(dui)(dui)焊(han)(han)(han)(han)加(jia)強管(guan)(guan)(guan)(guan)(guan)(guan)(guan)接(jie)頭(tou)、承(cheng)(cheng)(cheng)插焊(han)(han)(han)(han)或(huo)螺(luo)(luo)(luo)紋(wen)(wen)連(lian)接(jie)三通、承(cheng)(cheng)(cheng)插焊(han)(han)(han)(han)或(huo)螺(luo)(luo)(luo)紋(wen)(wen)加(jia)強管(guan)(guan)(guan)(guan)(guan)(guan)(guan)接(jie)頭(tou)的(de)(de)(de)順序選用(yong)。值得注意的(de)(de)(de)是在(zai)確(que)定支(zhi)(zhi)管(guan)(guan)(guan)(guan)(guan)(guan)(guan)連(lian)接(jie)件(jian)(jian)(jian)(jian)的(de)(de)(de)管(guan)(guan)(guan)(guan)(guan)(guan)(guan)子(zi)(zi)(zi)表號(hao)時，應(ying)根(gen)據管(guan)(guan)(guan)(guan)(guan)(guan)(guan)子(zi)(zi)(zi)與(yu)管(guan)(guan)(guan)(guan)(guan)(guan)(guan)件(jian)(jian)(jian)(jian)等強度(du)的(de)(de)(de)原則(ze)以及管(guan)(guan)(guan)(guan)(guan)(guan)(guan)件(jian)(jian)(jian)(jian)與(yu)管(guan)(guan)(guan)(guan)(guan)(guan)(guan)子(zi)(zi)(zi)連(lian)接(jie)方式而定。例如(ru)，當管(guan)(guan)(guan)(guan)(guan)(guan)(guan)子(zi)(zi)(zi)與(yu)管(guan)(guan)(guan)(guan)(guan)(guan)(guan)件(jian)(jian)(jian)(jian)采用(yong)對(dui)(dui)焊(han)(han)(han)(han)連(lian)接(jie)時，管(guan)(guan)(guan)(guan)(guan)(guan)(guan)子(zi)(zi)(zi)與(yu)管(guan)(guan)(guan)(guan)(guan)(guan)(guan)件(jian)(jian)(jian)(jian)的(de)(de)(de)管(guan)(guan)(guan)(guan)(guan)(guan)(guan)子(zi)(zi)(zi)表號(hao)應(ying)一致；而當管(guan)(guan)(guan)(guan)(guan)(guan)(guan)子(zi)(zi)(zi)與(yu)管(guan)(guan)(guan)(guan)(guan)(guan)(guan)件(jian)(jian)(jian)(jian)采用(yong)承(cheng)(cheng)(cheng)插焊(han)(han)(han)(han)或(huo)螺(luo)(luo)(luo)紋(wen)(wen)連(lian)接(jie)時，標準(zhun)的(de)(de)(de)承(cheng)(cheng)(cheng)插焊(han)(han)(han)(han)和螺(luo)(luo)(luo)紋(wen)(wen)管(guan)(guan)(guan)(guan)(guan)(guan)(guan)件(jian)(jian)(jian)(jian)的(de)(de)(de)管(guan)(guan)(guan)(guan)(guan)(guan)(guan)子(zi)(zi)(zi)表號(hao)只(zhi)有Sch80、Sch60、XXS，最低(di)的(de)(de)(de)管(guan)(guan)(guan)(guan)(guan)(guan)(guan)子(zi)(zi)(zi)表號(hao)就是Sch80，也就是說只(zhi)要(yao)當承(cheng)(cheng)(cheng)插焊(han)(han)(han)(han)或(huo)螺(luo)(luo)(luo)紋(wen)(wen)管(guan)(guan)(guan)(guan)(guan)(guan)(guan)件(jian)(jian)(jian)(jian)所(suo)連(lian)接(jie)的(de)(de)(de)管(guan)(guan)(guan)(guan)(guan)(guan)(guan)子(zi)(zi)(zi)表號(hao)不大(da)于(yu)Sch80時，承(cheng)(cheng)(cheng)插焊(han)(han)(han)(han)或(huo)螺(luo)(luo)(luo)紋(wen)(wen)管(guan)(guan)(guan)(guan)(guan)(guan)(guan)件(jian)(jian)(jian)(jian)的(de)(de)(de)管(guan)(guan)(guan)(guan)(guan)(guan)(guan)子(zi)(zi)(zi)表號(hao)就選Sch80。而當所(suo)連(lian)接(jie)的(de)(de)(de)管(guan)(guan)(guan)(guan)(guan)(guan)(guan)子(zi)(zi)(zi)表號(hao)大(da)于(yu)Sch80時，承(cheng)(cheng)(cheng)插焊(han)(han)(han)(han)或(huo)螺(luo)(luo)(luo)紋(wen)(wen)管(guan)(guan)(guan)(guan)(guan)(guan)(guan)件(jian)(jian)(jian)(jian)的(de)(de)(de)管(guan)(guan)(guan)(guan)(guan)(guan)(guan)子(zi)(zi)(zi)表號(hao)就選Sch60或(huo)XXS。

   f. 當對焊(han)三(san)通主管(guan)(guan)(guan)、支(zhi)管(guan)(guan)(guan)所(suo)連接的(de)管(guan)(guan)(guan)子的(de)管(guan)(guan)(guan)子表號不同(tong)時，應(ying)注意三(san)通主管(guan)(guan)(guan)、支(zhi)管(guan)(guan)(guan)端(duan)部的(de)管(guan)(guan)(guan)子表號應(ying)分別與其(qi)所(suo)連接的(de)管(guan)(guan)(guan)子的(de)管(guan)(guan)(guan)子表號相(xiang)同(tong)，這樣就非常方便(bian)管(guan)(guan)(guan)道施工，管(guan)(guan)(guan)件不必(bi)現場再打(da)坡(po)口。

 ③. 分(fen)支(zhi)管與(yu)主管連接的管件選擇見表(biao)16.71。