Welded Patch With an R Stamp but No Repair Records
During an external inspection of an 800-gallon air receiver, the inspector finds a welded patch on the shell near the bottom head. The patch is 8 inches by 10 inches and is welded to the shell. The nameplate shows 200-psig MAWP, built 1995, and a small R stamp near the nameplate. No repair records are available; the owner says the patch was installed about 10 years ago by a contractor who no longer exists. The patch has no visible leaks, but the weld has undercut and the patch was not post-weld heat treated. The vessel is in air service and has a relief valve set at 200 psig. The inspector must decide whether the patch is acceptable, what documentation is needed, and what follow-up is required.
1. What does the presence of an R stamp without records indicate, and can the inspector accept the patch?
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An R stamp on or near the nameplate is evidence that a repair was intended to be Code work, but it is not proof that the repair is acceptable. NBIC Part 2 requires the inspector to review repair records; without an R-1, WPS/PQR, NDE, and test records, the inspector cannot verify who did the work, what procedure was used, or whether the patch restored the required thickness. I would not accept the patch on the stamp alone. The undercut and missing PWHT are additional concerns; PWHT is not automatically required for every air receiver, but it must be evaluated against the material, thickness, and original Code. The inspector should document the patch dimensions, weld condition, and any corrosion, and require further evaluation before return to service.
2. What inspection and evaluation would you require?
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Required inspection includes visual examination of the patch and weld for cracks, undercut, overlap, and corrosion; PT or MT of the weld; UT thickness mapping of the patch and adjacent shell; and a check of the patch material and welder identification if available. If the original Code required PWHT or if the thickness and material trigger it, verify heat treatment or require engineering evaluation. The inspector should also check the relief valve set pressure and the vessel's current MAWP. If the patch is a temporary repair, it must be identified as such and not treated as permanent. The evaluation should confirm that the patch and shell can carry the pressure at 200 psig.
3. If records cannot be found, what are the options?
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If records cannot be found, options are: perform a fitness-for-service evaluation and NDE to qualify the patch as-is; repair or replace the patch by an R-stamp holder with full documentation; rerate the vessel to a lower pressure; or remove the vessel from service. The inspector should not invent records or accept a verbal history. The owner should be given a written deficiency and a deadline. If the jurisdiction requires Code records for the repair, the vessel may need to be treated as unverified until the repair is documented or redone. The inspector's final report should state the basis for acceptance or rejection.