I am looking for code or standard requirements, that cover value of minimum distance between circumferential welds in pipes.
In our case, the pipeline is designed under provisions of ASME Section IX and ASME B31.9 Codes.
There are requirements as per code but generally there are two rules of thumb, which one you use is up to you. They are either use 2 times the diameter or 8 times the wall thickness of the pipe.