When repairs are made to code pressure vessels, the National Board Inspection Code (NBIC) classifies them into three categories: alterations, repairs, and routine repairs. Alterations are the most significant type of repair. Examples of alterations are adding a new nozzle, changing materials of a vessel part, or changing the configuration of a vessel. Alterations usually require calculations for the new vessel parts, and a hydrostatic test after completion. Standard repairs involve things like replacing a corroded or damaged vessel part. If the new materials are the same as the original, then calculations are not required. Testing may be by hydro test or liquid penetrant testing. A routine repair is something more like grinding out and re-welding a pinhole or small crack, or seal welding a leaking tube end. Liquid penetrant testing is sufficient for routine repairs. For any type of repair, the company performing the repair needs to have an NBIC ‘R’ stamp, and the repair plans and required testing are always subject to the review and approval of the Authorized Inspector.
TEMA Update – The 10th edition of the TEMA Standards are available for purchase as of April 15th, 2019. Please visit www.tema.org to get your copy on order today!