Pipe Design - Length between Buttwelds

[Metalmeister]

Does anyone know of a Code reference or limit that specifies a minimum distance between pipe buttwelds such as 1.5D for example. I looked but can't find any such limit in B31.1 or ASME III. Maybe I missed it or it is covered in another piping code. Thanks and Merry Christmas/Happy Holidays to all.

 

[nickelkid]

Pipe Spools / Pup min. lengths

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[fortmceng]

In B31.3 or ASME Sec VII D1, there is no code restriction that would restrict you from keeping two welds close or overlap. If you are worried about the quality of the joint, you could do a mock up test and go for 100% RT.

 

[BigInch]

If you have an option, its generally considered to be 1 diameter, but its not written in stone.

**********************
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[KevinNZ]

The problem as I read it is with the closest of the heat effected zones of two welds and this giving a stress riser becuase of the local hardness change. This would only be a problem with the welds being in the order of wall thickness apart not pipe diameters.

What I have seen only seems to think it's a problem with high spec steels and carbon steel is not a problem. Pisses me off when inspectors do not allow close welds but can not back up why.

Kevin

 

[Metalmeister]

Thanks to all for your feedback and for the previous thread line. You have been very helpful.