I have read UG-129 in ASME Section VIII, but it does not mention that a PSV number is required in the "marking" (nameplate). In the U.S. on ASME VIII pressure vessels, is there some code or standard that requires the PSV to have a tag identifying its instrument number, e.g. the PSV is "PSV-100A" on "V-100"? Does it have to be a permanently affixed tag or can it be attached with a car sealed wire?
I am asking because our client has PSVs (with permanently affixed nameplates identifying the PSV tag number) that switch between multiple vessels and the service shop. Say they have 3 vessels "V-101, V-102, V-103" and six PSVs "PSV-101A, PSV-101B, PSV-102A, PSV-102B, PSV-103A, PSV-103B". Each vessel only has one PSV on it at a time, while the other is in storage or in the shop. Also, each PSV could be on any vessel, e.g. PSV-103A could at one time be on V-101 then later be on V-102. Is this acceptable? I would say this would not be allowed since the P&ID would show the wrong PSV tag number unless the P&IDs are updated every time the valves are switched.