pipe weld question

[billMcL]

A large machine we build and sell has an air compressor that feeds an air holding tank. The compressor is either diesel or electric motor driven. The air holding tank is an ASME "U" stamped pressure vessel, MAWP is 250 psi.

There is a short pipe piece that connects the air compressor to the ASME air tank. The pipe is basically a 90 deg. elbow with a butt welded flange on each end. (8" nom. dia.) This pipe spool piece connects the compressor and the ASME pressure vessel. (there is a vibration coupling in the line also.) This pipe piece is a subcontracted purchased item, and I recently noticed visually some weld quality issues on the flange welds.

My question is: Is the manufacturer (vendor) of this welded pipe piece required to have some code qualification, welder certification, or certificate of authorization, ...like a "PP" stamp?
Thx!

 

[metengr]

No, not for this specific application. The PP stamp would apply to piping under ASME Section I boiler external. For your case, the applicable code is ASME Section VIII, Div 1 up to the face of the first flange or nozzle weld end prep off of the air tank. Past this point is under ASME B31 Pressure Piping administration, if you specify in the contract documents, or your local Jurisdiction mandates specific use of a Pressure Piping Standard.

 

[TBP]

The shop supplying the pipe assembly should be using welders qualified under Section IX. In many jurisdictions, the shop will need to have a QA program in place for ASME pressure piping work, in addition to the welding qualification. Depending upon where your shop is, and where your customers are located, your company could be exposed to some significant liability issues.