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. 支管連接件的選擇(ze)

   a. 主要根據管(guan)(guan)道(dao)的(de)(de)設計(ji)溫(wen)度、設計(ji)壓力、腐蝕余(yu)量(liang)等(deng)設計(ji)條件確定(ding)的(de)(de)。分支的(de)(de)方(fang)法：對于低壓大直徑(jing)管(guan)(guan)則直接把分支管(guan)(guan)焊(han)于主管(guan)(guan)上，另外多(duo)數(shu)是利用(yong)分支管(guan)(guan)件進行(xing)分支。

   b. 當從(cong)主(zhu)管(guan)(guan)(guan)(guan)(guan)引出(chu)支管(guan)(guan)(guan)(guan)(guan)時，支管(guan)(guan)(guan)(guan)(guan)直(zhi)徑(jing)(jing)與(yu)主(zhu)管(guan)(guan)(guan)(guan)(guan)直(zhi)徑(jing)(jing)的比值大于等(deng)于0.5時，采(cai)用(yong)(yong)異(yi)徑(jing)(jing)三(san)通或(huo)等(deng)徑(jing)(jing)三(san)通，當主(zhu)支管(guan)(guan)(guan)(guan)(guan)為等(deng)徑(jing)(jing)時，應采(cai)用(yong)(yong)三(san)通。GB50316 規定：公稱(cheng)壓力大于或(huo)等(deng)于10MPa的管(guan)(guan)(guan)(guan)(guan)道，主(zhu)支管(guan)(guan)(guan)(guan)(guan)為異(yi)徑(jing)(jing)時，不宜采(cai)用(yong)(yong)焊(han)接支管(guan)(guan)(guan)(guan)(guan)，宜采(cai)用(yong)(yong)三(san)通或(huo)在主(zhu)管(guan)(guan)(guan)(guan)(guan)上開孔并(bing)焊(han)接支管(guan)(guan)(guan)(guan)(guan)臺(tai)。當主(zhu)管(guan)(guan)(guan)(guan)(guan)直(zhi)徑(jing)(jing)大于DN65而(er)支管(guan)(guan)(guan)(guan)(guan)直(zhi)徑(jing)(jing)為DN40及以下時，根據設計壓力的大小，采(cai)用(yong)(yong)支管(guan)(guan)(guan)(guan)(guan)臺(tai)或(huo)半管(guan)(guan)(guan)(guan)(guan)接頭。

   c. 主(zhu)(zhu)管(guan)(guan)(guan)(guan)直(zhi)(zhi)徑(jing)小(xiao)(xiao)于(yu)(yu)DN50時，支(zhi)管(guan)(guan)(guan)(guan)小(xiao)(xiao)于(yu)(yu)主(zhu)(zhu)管(guan)(guan)(guan)(guan)，則用異(yi)徑(jing)三通(tong)(tong)(tong)或(huo)(huo)等(deng)徑(jing)三通(tong)(tong)(tong)加異(yi)徑(jing)短管(guan)(guan)(guan)(guan)。設(she)計壓(ya)力(li)等(deng)于(yu)(yu)或(huo)(huo)大(da)(da)于(yu)(yu)2.0MPa、設(she)計溫(wen)度(du)超過250℃以及支(zhi)管(guan)(guan)(guan)(guan)與主(zhu)(zhu)管(guan)(guan)(guan)(guan)公稱(cheng)直(zhi)(zhi)徑(jing)之比(bi)大(da)(da)于(yu)(yu)0.8，或(huo)(huo)承受機械振動(dong)、壓(ya)力(li)脈(mo)動(dong)和溫(wen)度(du)急(ji)劇變(bian)化的(de)(de)管(guan)(guan)(guan)(guan)道(dao)分支(zhi)，應(ying)采用等(deng)徑(jing)異(yi)徑(jing)三通(tong)(tong)(tong)；公稱(cheng)直(zhi)(zhi)徑(jing)小(xiao)(xiao)于(yu)(yu)或(huo)(huo)等(deng)于(yu)(yu)40mm的(de)(de)管(guan)(guan)(guan)(guan)道(dao)，應(ying)采用承插(cha)焊(han)(han)(han)(han)(han)（或(huo)(huo)螺(luo)紋(wen)）鍛制三通(tong)(tong)(tong)；公稱(cheng)直(zhi)(zhi)徑(jing)等(deng)于(yu)(yu)或(huo)(huo)大(da)(da)于(yu)(yu)50mm的(de)(de)管(guan)(guan)(guan)(guan)道(dao)，應(ying)采用對(dui)焊(han)(han)(han)(han)(han)三通(tong)(tong)(tong)、對(dui)焊(han)(han)(han)(han)(han)加強(qiang)(qiang)管(guan)(guan)(guan)(guan)接頭(tou)（對(dui)焊(han)(han)(han)(han)(han)支(zhi)管(guan)(guan)(guan)(guan)臺）或(huo)(huo)嵌入式（鞍型）支(zhi)管(guan)(guan)(guan)(guan)接頭(tou)。支(zhi)管(guan)(guan)(guan)(guan)通(tong)(tong)(tong)過加強(qiang)(qiang)管(guan)(guan)(guan)(guan)接頭(tou)（支(zhi)管(guan)(guan)(guan)(guan)臺）與主(zhu)(zhu)管(guan)(guan)(guan)(guan)連接是指將一個螺(luo)紋(wen)、承插(cha)焊(han)(han)(han)(han)(han)或(huo)(huo)對(dui)焊(han)(han)(han)(han)(han)的(de)(de)管(guan)(guan)(guan)(guan)接頭(tou)或(huo)(huo)半管(guan)(guan)(guan)(guan)接頭(tou)（支(zhi)管(guan)(guan)(guan)(guan)臺）直(zhi)(zhi)接焊(han)(han)(han)(han)(han)于(yu)(yu)主(zhu)(zhu)管(guan)(guan)(guan)(guan)上而制成，螺(luo)紋(wen)、承插(cha)焊(han)(han)(han)(han)(han)支(zhi)管(guan)(guan)(guan)(guan)臺用于(yu)(yu)直(zhi)(zhi)徑(jing)小(xiao)(xiao)于(yu)(yu)等(deng)于(yu)(yu)DN40（NPS1/2）的(de)(de)支(zhi)管(guan)(guan)(guan)(guan)連接。螺(luo)紋(wen)、承插(cha)焊(han)(han)(han)(han)(han)支(zhi)管(guan)(guan)(guan)(guan)臺在(zai)任何情況下其額定等(deng)級(ji)應(ying)大(da)(da)于(yu)(yu)等(deng)于(yu)(yu)20001b。

   d. 其(qi)他(ta)支(zhi)管連(lian)接(jie)可用直接(jie)焊接(jie)，但必(bi)須(xu)經校核后明確是否(fou)增加(jia)(jia)補強。直接(jie)焊接(jie)在主管上的(de)(de)(de)支(zhi)管連(lian)接(jie)，不(bu)宜用于(yu)有機(ji)械振動(dong)、壓力(li)脈動(dong)和溫度急(ji)劇變(bian)化的(de)(de)(de)部位及設計溫度超過(guo)425℃的(de)(de)(de)管道，當支(zhi)管連(lian)接(jie)處(chu)承(cheng)受由于(yu)支(zhi)管熱變(bian)形、外載荷及支(zhi)架位移等引(yin)起的(de)(de)(de)應力(li)時，應對附加(jia)(jia)載荷在支(zhi)管連(lian)接(jie)處(chu)產生(sheng)的(de)(de)(de)影響進(jin)行(xing)分析并(bing)采取(qu)必(bi)要的(de)(de)(de)加(jia)(jia)強措施。

   e. 實際設計過程(cheng)中(zhong)，主(zhu)(zhu)要依據(ju)(ju)管(guan)(guan)(guan)(guan)(guan)(guan)道(dao)等級中(zhong)已(yi)經(jing)確定(ding)的(de)法(fa)蘭壓(ya)力等級或(huo)(huo)公(gong)稱壓(ya)力（PN）來選用(yong)(yong)支(zhi)管(guan)(guan)(guan)(guan)(guan)(guan)連(lian)(lian)接(jie)(jie)件。一般情況下，當(dang)法(fa)蘭的(de)公(gong)稱壓(ya)力PN≤2.5MPa時(shi)(shi)，支(zhi)管(guan)(guan)(guan)(guan)(guan)(guan)直(zhi)接(jie)(jie)焊(han)(han)(han)接(jie)(jie)在主(zhu)(zhu)管(guan)(guan)(guan)(guan)(guan)(guan)上(shang)；當(dang)PN≥4.0MPa時(shi)(shi)，則(ze)根據(ju)(ju)主(zhu)(zhu)管(guan)(guan)(guan)(guan)(guan)(guan)支(zhi)管(guan)(guan)(guan)(guan)(guan)(guan)公(gong)稱直(zhi)徑的(de)不同按對(dui)(dui)焊(han)(han)(han)三通、對(dui)(dui)焊(han)(han)(han)加強(qiang)管(guan)(guan)(guan)(guan)(guan)(guan)接(jie)(jie)頭、承(cheng)插(cha)焊(han)(han)(han)或(huo)(huo)螺(luo)紋(wen)(wen)(wen)連(lian)(lian)接(jie)(jie)三通、承(cheng)插(cha)焊(han)(han)(han)或(huo)(huo)螺(luo)紋(wen)(wen)(wen)加強(qiang)管(guan)(guan)(guan)(guan)(guan)(guan)接(jie)(jie)頭的(de)順序(xu)選用(yong)(yong)。值得注意的(de)是(shi)在確定(ding)支(zhi)管(guan)(guan)(guan)(guan)(guan)(guan)連(lian)(lian)接(jie)(jie)件的(de)管(guan)(guan)(guan)(guan)(guan)(guan)子(zi)(zi)表號時(shi)(shi)，應根據(ju)(ju)管(guan)(guan)(guan)(guan)(guan)(guan)子(zi)(zi)與管(guan)(guan)(guan)(guan)(guan)(guan)件等強(qiang)度的(de)原則(ze)以及管(guan)(guan)(guan)(guan)(guan)(guan)件與管(guan)(guan)(guan)(guan)(guan)(guan)子(zi)(zi)連(lian)(lian)接(jie)(jie)方(fang)式而定(ding)。例(li)如(ru)，當(dang)管(guan)(guan)(guan)(guan)(guan)(guan)子(zi)(zi)與管(guan)(guan)(guan)(guan)(guan)(guan)件采(cai)用(yong)(yong)對(dui)(dui)焊(han)(han)(han)連(lian)(lian)接(jie)(jie)時(shi)(shi)，管(guan)(guan)(guan)(guan)(guan)(guan)子(zi)(zi)與管(guan)(guan)(guan)(guan)(guan)(guan)件的(de)管(guan)(guan)(guan)(guan)(guan)(guan)子(zi)(zi)表號應一致；而當(dang)管(guan)(guan)(guan)(guan)(guan)(guan)子(zi)(zi)與管(guan)(guan)(guan)(guan)(guan)(guan)件采(cai)用(yong)(yong)承(cheng)插(cha)焊(han)(han)(han)或(huo)(huo)螺(luo)紋(wen)(wen)(wen)連(lian)(lian)接(jie)(jie)時(shi)(shi)，標(biao)準的(de)承(cheng)插(cha)焊(han)(han)(han)和(he)螺(luo)紋(wen)(wen)(wen)管(guan)(guan)(guan)(guan)(guan)(guan)件的(de)管(guan)(guan)(guan)(guan)(guan)(guan)子(zi)(zi)表號只有Sch80、Sch60、XXS，最(zui)低的(de)管(guan)(guan)(guan)(guan)(guan)(guan)子(zi)(zi)表號就(jiu)是(shi)Sch80，也就(jiu)是(shi)說只要當(dang)承(cheng)插(cha)焊(han)(han)(han)或(huo)(huo)螺(luo)紋(wen)(wen)(wen)管(guan)(guan)(guan)(guan)(guan)(guan)件所連(lian)(lian)接(jie)(jie)的(de)管(guan)(guan)(guan)(guan)(guan)(guan)子(zi)(zi)表號不大于(yu)Sch80時(shi)(shi)，承(cheng)插(cha)焊(han)(han)(han)或(huo)(huo)螺(luo)紋(wen)(wen)(wen)管(guan)(guan)(guan)(guan)(guan)(guan)件的(de)管(guan)(guan)(guan)(guan)(guan)(guan)子(zi)(zi)表號就(jiu)選Sch80。而當(dang)所連(lian)(lian)接(jie)(jie)的(de)管(guan)(guan)(guan)(guan)(guan)(guan)子(zi)(zi)表號大于(yu)Sch80時(shi)(shi)，承(cheng)插(cha)焊(han)(han)(han)或(huo)(huo)螺(luo)紋(wen)(wen)(wen)管(guan)(guan)(guan)(guan)(guan)(guan)件的(de)管(guan)(guan)(guan)(guan)(guan)(guan)子(zi)(zi)表號就(jiu)選Sch60或(huo)(huo)XXS。

   f. 當對焊三通(tong)主管(guan)(guan)(guan)(guan)、支(zhi)管(guan)(guan)(guan)(guan)所連接的(de)管(guan)(guan)(guan)(guan)子的(de)管(guan)(guan)(guan)(guan)子表號不(bu)同時，應(ying)注意三通(tong)主管(guan)(guan)(guan)(guan)、支(zhi)管(guan)(guan)(guan)(guan)端部(bu)的(de)管(guan)(guan)(guan)(guan)子表號應(ying)分別與其所連接的(de)管(guan)(guan)(guan)(guan)子的(de)管(guan)(guan)(guan)(guan)子表號相同，這樣就非常方便管(guan)(guan)(guan)(guan)道施工(gong)，管(guan)(guan)(guan)(guan)件不(bu)必現場再打坡(po)口。

 ③. 分支(zhi)管與主(zhu)管連接的管件選擇見表16.71。