Understanding of \"straight pipe sections\" in pipeline weld layout
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I encountered a situation at work where there was a disagreement regarding the interpretation of certain standard provisions; could you help explain it? Thank you! Industry: Chemical pipeline installation. Standard specification: GB/T 20801.4 7.6 Weld arrangement a) The distance between the centers of two butt welds on a straight pipe section shall not be less than 150 mm when the nominal diameter is 150 mm or greater ； When the nominal diameter is less than 150 millimeters, it shall be not less than the outer diameter of the pipe. Question: There is disagreement regarding the understanding of “straight pipe sections” in weld layout. Example: Is the length of the pipe between two standard elbows suitable for this requirement? This requirement is intended to control the area affected by heat during welding; according to ASME and **relevant design codes, the minimum distance should be 3 times the thickness of the plate, with a minimum value of 50 millimeters. Is there any authoritative explanation for this article? If available, please provide it. Thank you so much!
I believe the pipe length between two standard elbows applies equally to this case as well. ---I can’t give a reason either, haha.