This is another example of a change to our process that may not require a wrench to complete, but it is my opinion, as well as now the National Board’s, that changing the service of a pressure vessel is indeed a change that should undergo an MOC. The National Board Inspection Code (NBIC) Part 2, SUPPLEMENT 9, REQUIREMENTS FOR CHANGE OF SERVICE offers a very much needed insight into all that should be considered when changing the service of a pressure vessel. AND for those who purchase USED pressure vessels with a KNOWN HISTORY and your usage would be a “change in service”, you too should consider these items/requirements for your change in service.