Repair Procedure Approval Under Time Pressure
A tank maintenance crew discovers a 300 mm long, full-thickness crack in the shell-to-bottom weld of an aboveground storage tank during an internal inspection. The tank is 30 m diameter, in gasoline service, and the owner wants it back in service in 5 days because of a supply commitment. The contractor proposes welding the crack without a written repair procedure, arguing that the welders are qualified and the repair is 'routine.' The API ICP inspector is asked to approve the approach verbally so work can start on the night shift. The owner's representative says a verbal approval is fine because the written procedure can follow.
1. What is the inspector's correct response to the request for verbal approval?
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The inspector should decline to give verbal approval. A shell-to-bottom weld crack in a flammable-service tank is a pressure- and product-boundary repair, not routine maintenance. It requires a written repair procedure, review and approval by the authorized inspector, qualified welders and qualified procedures, and appropriate NDE after the repair.
Key points to state: the repair affects the primary containment boundary; the applicable standard governs repair procedures and approvals; a verbal approval creates no defensible record and cannot be reconciled with the required documentation. The inspector can help the owner compress the schedule by prioritizing procedure review, but not by eliminating it. If the owner proceeds without approval, the inspector should document the objection and escalate.
2. What technical elements should the written repair procedure address for this crack?
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At minimum: the extent of the defect and how it was characterized; the excavation/removal method and confirmation that the crack is fully removed or properly treated; weld preparation geometry; base metal and weld metal selection for the service; preheat and interpass requirements; welding process and qualified procedure; welder qualification; distortion control; post-repair NDE method and acceptance criteria; and any post-weld heat treatment if required by the material and thickness. The procedure should also address how the shell-to-bottom junction geometry is restored and how the repair will be documented for the tank's records. The inspector reviews the procedure against the applicable standard and approves or returns it - that review is the approval step the owner wanted to skip.