Minimum weld spacing
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Minimum weld spacing is not specified in ASME B31.3; what are the requirements for foreign projects?
Avoid the heat-affected zone; 6 mm is generally sufficient
There doesn’t seem to be any specific regulations. As long as the welds don’t overlap, that’s fine!
ASME B31.3 – Regarding the spacing between two circumferential welds: Interpretation 7-02. Subject: ASME/ANSI B31.3-1987 Edition, Paragraphs 304.3.3 and 328; Spacing of Welds. Date issued: May 24, 1988. File reference: B31-87-039. Question: According to ASME/ANSI B31.3, are there any requirements or guidelines regarding the minimum distance between welds in a pipe? Answer: No, except as specified in paragraph 304.3.3(e). Interpretation 25-20. Subject: B31.3-2012, Interpretation of Fig. 328.5.4D – Acceptable details for welds used to attach branches to a pipe. Date issued: September 25, 2014. File reference: 14-1470. Question 6: Does ASME B31.3 provide any rules, restrictions, or limits regarding the distance between circumferential butt welds in a piping assembly? Answer 6: No.
B31.3 does not specify any requirements in this regard; in some domestic standards for the construction of petrochemical, oil, and chemical pipelines, the minimum requirement is usually one time the diameter of the pipe, or 100 mm or 150 mm. Of course, as a construction contractor, following the standards specified in the design documents should not pose any major problems. However, upon closer examination of the spacing values for the welds, I believe that by avoiding the heat-affected zones at both ends of the welds, secondary heat treatment will not have an adverse effect on the mechanical properties of the material.