①. 由于各國管(guan)件(jian)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(guan)連接件的選(xuan)擇
a. 主(zhu)(zhu)要根據(ju)管(guan)(guan)道的(de)設(she)計溫度、設(she)計壓力、腐(fu)蝕余量等設(she)計條件(jian)確(que)定的(de)。分(fen)支的(de)方(fang)法：對于低(di)壓大直徑管(guan)(guan)則直接把(ba)分(fen)支管(guan)(guan)焊于主(zhu)(zhu)管(guan)(guan)上(shang)，另外多數(shu)是利(li)用(yong)分(fen)支管(guan)(guan)件(jian)進行分(fen)支。
b. 當從主(zhu)(zhu)管(guan)(guan)(guan)(guan)引(yin)出支(zhi)(zhi)管(guan)(guan)(guan)(guan)時(shi)，支(zhi)(zhi)管(guan)(guan)(guan)(guan)直徑(jing)(jing)(jing)(jing)(jing)與主(zhu)(zhu)管(guan)(guan)(guan)(guan)直徑(jing)(jing)(jing)(jing)(jing)的比(bi)值(zhi)大(da)(da)于(yu)(yu)等于(yu)(yu)0.5時(shi)，采用(yong)異(yi)徑(jing)(jing)(jing)(jing)(jing)三(san)通(tong)(tong)或(huo)等徑(jing)(jing)(jing)(jing)(jing)三(san)通(tong)(tong)，當主(zhu)(zhu)支(zhi)(zhi)管(guan)(guan)(guan)(guan)為等徑(jing)(jing)(jing)(jing)(jing)時(shi)，應采用(yong)三(san)通(tong)(tong)。GB50316 規定：公稱壓力大(da)(da)于(yu)(yu)或(huo)等于(yu)(yu)10MPa的管(guan)(guan)(guan)(guan)道，主(zhu)(zhu)支(zhi)(zhi)管(guan)(guan)(guan)(guan)為異(yi)徑(jing)(jing)(jing)(jing)(jing)時(shi)，不(bu)宜采用(yong)焊(han)接支(zhi)(zhi)管(guan)(guan)(guan)(guan)，宜采用(yong)三(san)通(tong)(tong)或(huo)在主(zhu)(zhu)管(guan)(guan)(guan)(guan)上開孔并焊(han)接支(zhi)(zhi)管(guan)(guan)(guan)(guan)臺。當主(zhu)(zhu)管(guan)(guan)(guan)(guan)直徑(jing)(jing)(jing)(jing)(jing)大(da)(da)于(yu)(yu)DN65而支(zhi)(zhi)管(guan)(guan)(guan)(guan)直徑(jing)(jing)(jing)(jing)(jing)為DN40及以下(xia)時(shi)，根(gen)據設計壓力的大(da)(da)小，采用(yong)支(zhi)(zhi)管(guan)(guan)(guan)(guan)臺或(huo)半(ban)管(guan)(guan)(guan)(guan)接頭(tou)。
c. 主(zhu)(zhu)管(guan)(guan)(guan)直(zhi)徑(jing)(jing)小于(yu)(yu)(yu)DN50時，支(zhi)管(guan)(guan)(guan)小于(yu)(yu)(yu)主(zhu)(zhu)管(guan)(guan)(guan)，則用(yong)異(yi)徑(jing)(jing)三(san)通或(huo)等徑(jing)(jing)三(san)通加(jia)異(yi)徑(jing)(jing)短(duan)管(guan)(guan)(guan)。設(she)計壓力(li)等于(yu)(yu)(yu)或(huo)大(da)于(yu)(yu)(yu)2.0MPa、設(she)計溫度(du)超過(guo)250℃以及支(zhi)管(guan)(guan)(guan)與(yu)主(zhu)(zhu)管(guan)(guan)(guan)公(gong)稱直(zhi)徑(jing)(jing)之比大(da)于(yu)(yu)(yu)0.8，或(huo)承(cheng)受機械振動、壓力(li)脈(mo)動和(he)溫度(du)急劇(ju)變化(hua)的管(guan)(guan)(guan)道分(fen)支(zhi)，應(ying)采用(yong)等徑(jing)(jing)異(yi)徑(jing)(jing)三(san)通；公(gong)稱直(zhi)徑(jing)(jing)小于(yu)(yu)(yu)或(huo)等于(yu)(yu)(yu)40mm的管(guan)(guan)(guan)道，應(ying)采用(yong)承(cheng)插焊(han)(han)(han)(han)（或(huo)螺(luo)(luo)紋）鍛制(zhi)三(san)通；公(gong)稱直(zhi)徑(jing)(jing)等于(yu)(yu)(yu)或(huo)大(da)于(yu)(yu)(yu)50mm的管(guan)(guan)(guan)道，應(ying)采用(yong)對焊(han)(han)(han)(han)三(san)通、對焊(han)(han)(han)(han)加(jia)強(qiang)管(guan)(guan)(guan)接頭（對焊(han)(han)(han)(han)支(zhi)管(guan)(guan)(guan)臺）或(huo)嵌入式（鞍型）支(zhi)管(guan)(guan)(guan)接頭。支(zhi)管(guan)(guan)(guan)通過(guo)加(jia)強(qiang)管(guan)(guan)(guan)接頭（支(zhi)管(guan)(guan)(guan)臺）與(yu)主(zhu)(zhu)管(guan)(guan)(guan)連接是指將一個螺(luo)(luo)紋、承(cheng)插焊(han)(han)(han)(han)或(huo)對焊(han)(han)(han)(han)的管(guan)(guan)(guan)接頭或(huo)半(ban)管(guan)(guan)(guan)接頭（支(zhi)管(guan)(guan)(guan)臺）直(zhi)接焊(han)(han)(han)(han)于(yu)(yu)(yu)主(zhu)(zhu)管(guan)(guan)(guan)上而(er)制(zhi)成，螺(luo)(luo)紋、承(cheng)插焊(han)(han)(han)(han)支(zhi)管(guan)(guan)(guan)臺用(yong)于(yu)(yu)(yu)直(zhi)徑(jing)(jing)小于(yu)(yu)(yu)等于(yu)(yu)(yu)DN40（NPS1/2）的支(zhi)管(guan)(guan)(guan)連接。螺(luo)(luo)紋、承(cheng)插焊(han)(han)(han)(han)支(zhi)管(guan)(guan)(guan)臺在任何情(qing)況下其額定等級應(ying)大(da)于(yu)(yu)(yu)等于(yu)(yu)(yu)20001b。
d. 其他支(zhi)(zhi)管(guan)連(lian)接(jie)(jie)(jie)(jie)可(ke)用直接(jie)(jie)(jie)(jie)焊接(jie)(jie)(jie)(jie)，但必(bi)須經(jing)校核后明確是否增加(jia)補強(qiang)。直接(jie)(jie)(jie)(jie)焊接(jie)(jie)(jie)(jie)在主管(guan)上的(de)支(zhi)(zhi)管(guan)連(lian)接(jie)(jie)(jie)(jie)，不宜用于有(you)機械(xie)振動、壓力(li)脈動和溫度(du)急劇變化(hua)的(de)部位及(ji)設計溫度(du)超過(guo)425℃的(de)管(guan)道，當(dang)支(zhi)(zhi)管(guan)連(lian)接(jie)(jie)(jie)(jie)處承受由于支(zhi)(zhi)管(guan)熱變形、外載(zai)荷及(ji)支(zhi)(zhi)架位移等(deng)引起的(de)應(ying)力(li)時，應(ying)對(dui)附加(jia)載(zai)荷在支(zhi)(zhi)管(guan)連(lian)接(jie)(jie)(jie)(jie)處產生的(de)影響進行(xing)分析并采(cai)取必(bi)要的(de)加(jia)強(qiang)措施。
e. 實(shi)際設計過程中，主要(yao)依據(ju)(ju)管(guan)(guan)(guan)(guan)(guan)道等(deng)(deng)級中已經確定的(de)法蘭壓(ya)(ya)力(li)等(deng)(deng)級或(huo)(huo)公稱壓(ya)(ya)力(li)（PN）來選用(yong)(yong)(yong)支管(guan)(guan)(guan)(guan)(guan)連(lian)接(jie)(jie)(jie)件(jian)。一(yi)般(ban)情況下，當(dang)法蘭的(de)公稱壓(ya)(ya)力(li)PN≤2.5MPa時(shi)，支管(guan)(guan)(guan)(guan)(guan)直接(jie)(jie)(jie)焊(han)(han)(han)(han)接(jie)(jie)(jie)在(zai)主管(guan)(guan)(guan)(guan)(guan)上；當(dang)PN≥4.0MPa時(shi)，則根(gen)(gen)據(ju)(ju)主管(guan)(guan)(guan)(guan)(guan)支管(guan)(guan)(guan)(guan)(guan)公稱直徑的(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)接(jie)(jie)(jie)頭(tou)(tou)、承(cheng)(cheng)插(cha)(cha)(cha)(cha)焊(han)(han)(han)(han)或(huo)(huo)螺(luo)(luo)紋(wen)(wen)(wen)連(lian)接(jie)(jie)(jie)三通、承(cheng)(cheng)插(cha)(cha)(cha)(cha)焊(han)(han)(han)(han)或(huo)(huo)螺(luo)(luo)紋(wen)(wen)(wen)加(jia)強管(guan)(guan)(guan)(guan)(guan)接(jie)(jie)(jie)頭(tou)(tou)的(de)順序(xu)選用(yong)(yong)(yong)。值得注意的(de)是(shi)在(zai)確定支管(guan)(guan)(guan)(guan)(guan)連(lian)接(jie)(jie)(jie)件(jian)的(de)管(guan)(guan)(guan)(guan)(guan)子(zi)(zi)(zi)(zi)(zi)表(biao)(biao)號(hao)(hao)(hao)時(shi)，應(ying)根(gen)(gen)據(ju)(ju)管(guan)(guan)(guan)(guan)(guan)子(zi)(zi)(zi)(zi)(zi)與(yu)(yu)管(guan)(guan)(guan)(guan)(guan)件(jian)等(deng)(deng)強度的(de)原(yuan)則以(yi)及管(guan)(guan)(guan)(guan)(guan)件(jian)與(yu)(yu)管(guan)(guan)(guan)(guan)(guan)子(zi)(zi)(zi)(zi)(zi)連(lian)接(jie)(jie)(jie)方式而定。例如，當(dang)管(guan)(guan)(guan)(guan)(guan)子(zi)(zi)(zi)(zi)(zi)與(yu)(yu)管(guan)(guan)(guan)(guan)(guan)件(jian)采(cai)用(yong)(yong)(yong)對(dui)(dui)焊(han)(han)(han)(han)連(lian)接(jie)(jie)(jie)時(shi)，管(guan)(guan)(guan)(guan)(guan)子(zi)(zi)(zi)(zi)(zi)與(yu)(yu)管(guan)(guan)(guan)(guan)(guan)件(jian)的(de)管(guan)(guan)(guan)(guan)(guan)子(zi)(zi)(zi)(zi)(zi)表(biao)(biao)號(hao)(hao)(hao)應(ying)一(yi)致；而當(dang)管(guan)(guan)(guan)(guan)(guan)子(zi)(zi)(zi)(zi)(zi)與(yu)(yu)管(guan)(guan)(guan)(guan)(guan)件(jian)采(cai)用(yong)(yong)(yong)承(cheng)(cheng)插(cha)(cha)(cha)(cha)焊(han)(han)(han)(han)或(huo)(huo)螺(luo)(luo)紋(wen)(wen)(wen)連(lian)接(jie)(jie)(jie)時(shi)，標準的(de)承(cheng)(cheng)插(cha)(cha)(cha)(cha)焊(han)(han)(han)(han)和螺(luo)(luo)紋(wen)(wen)(wen)管(guan)(guan)(guan)(guan)(guan)件(jian)的(de)管(guan)(guan)(guan)(guan)(guan)子(zi)(zi)(zi)(zi)(zi)表(biao)(biao)號(hao)(hao)(hao)只(zhi)有(you)Sch80、Sch60、XXS，最低的(de)管(guan)(guan)(guan)(guan)(guan)子(zi)(zi)(zi)(zi)(zi)表(biao)(biao)號(hao)(hao)(hao)就(jiu)是(shi)Sch80，也就(jiu)是(shi)說只(zhi)要(yao)當(dang)承(cheng)(cheng)插(cha)(cha)(cha)(cha)焊(han)(han)(han)(han)或(huo)(huo)螺(luo)(luo)紋(wen)(wen)(wen)管(guan)(guan)(guan)(guan)(guan)件(jian)所(suo)連(lian)接(jie)(jie)(jie)的(de)管(guan)(guan)(guan)(guan)(guan)子(zi)(zi)(zi)(zi)(zi)表(biao)(biao)號(hao)(hao)(hao)不大(da)于(yu)Sch80時(shi)，承(cheng)(cheng)插(cha)(cha)(cha)(cha)焊(han)(han)(han)(han)或(huo)(huo)螺(luo)(luo)紋(wen)(wen)(wen)管(guan)(guan)(guan)(guan)(guan)件(jian)的(de)管(guan)(guan)(guan)(guan)(guan)子(zi)(zi)(zi)(zi)(zi)表(biao)(biao)號(hao)(hao)(hao)就(jiu)選Sch80。而當(dang)所(suo)連(lian)接(jie)(jie)(jie)的(de)管(guan)(guan)(guan)(guan)(guan)子(zi)(zi)(zi)(zi)(zi)表(biao)(biao)號(hao)(hao)(hao)大(da)于(yu)Sch80時(shi)，承(cheng)(cheng)插(cha)(cha)(cha)(cha)焊(han)(han)(han)(han)或(huo)(huo)螺(luo)(luo)紋(wen)(wen)(wen)管(guan)(guan)(guan)(guan)(guan)件(jian)的(de)管(guan)(guan)(guan)(guan)(guan)子(zi)(zi)(zi)(zi)(zi)表(biao)(biao)號(hao)(hao)(hao)就(jiu)選Sch60或(huo)(huo)XXS。
f. 當對焊(han)三通主管(guan)(guan)(guan)(guan)(guan)、支管(guan)(guan)(guan)(guan)(guan)所(suo)連接(jie)的(de)(de)管(guan)(guan)(guan)(guan)(guan)子(zi)的(de)(de)管(guan)(guan)(guan)(guan)(guan)子(zi)表號不同時，應注意三通主管(guan)(guan)(guan)(guan)(guan)、支管(guan)(guan)(guan)(guan)(guan)端部的(de)(de)管(guan)(guan)(guan)(guan)(guan)子(zi)表號應分別與其所(suo)連接(jie)的(de)(de)管(guan)(guan)(guan)(guan)(guan)子(zi)的(de)(de)管(guan)(guan)(guan)(guan)(guan)子(zi)表號相(xiang)同，這(zhe)樣就非常方便管(guan)(guan)(guan)(guan)(guan)道施工，管(guan)(guan)(guan)(guan)(guan)件不必現場(chang)再(zai)打坡口。
③. 分支管(guan)與主(zhu)管(guan)連接的(de)管(guan)件選擇見表(biao)16.71。
