Does B31.3 limit the number of times a defective weld can be repaired? We have stainless welds in the fuel gas system where some welds were repaired twice.
Metengr,thanks but the client is insisting on cutting out the joint as two repairs (or in other words one re-repair) has been done to some of the welds before their acceptance. If we have to cutout the pipe section from the existing line and replace with a pup piece does B31.3 or any relevant ASME code give guidance on the minimum distance between two butt welds?
No. the ASME Codes and Standards do not address minimum axial distance between butt welds. Follow good engineering practice by spacing them apart so as not to interfere with NDE.
qualitypro,
Check your piping specification - as metengr stated there is no code requirement to reject a weld based on multiple repairs so if the client has just decided they don't like something the rework is at their cost.
I frequently see that requirement (1 x repair only allowed) in piping specifications for Duplex, Super Duplex and Titanium materials but cannot remember seeing it listed for stainless welds.
As for the spacing between welds, that again should be listed in the piping specification if it is considered critical.
Regards,
DD
Review your Contract specification. If it only permits one repair, you must comply. If it does not limit the number of repairs, inform the Client in writing that the cut out will be charged to him at $$X as it is a Contract Change.
In most such contract requirements, only the complete, defective weld need be cut out and you do not need to replace with a pup piece; why make two welds unless dinensional requirements cannot be met?
With an austenitic stainless the number of repairs shouldn't be an issue. As someone else stated the Duplex grades are often limited to 1 or 2 repairs maximum. I believe this relates to the transformation of ferrite to austenite that occurs in these materials at elevated temperature. Regardless, if the customer insists you have to do it their way, make them pay if you can.
