Stress Analysis for existing PSV systems
Stress Analysis for existing PSV systems
(OP)
We have number of PSV systems in an 1970's refinery where the client is adding isolation valves on inlet and outlet lines of the PSV's. We want to know if we require to do stress analysis for these systems where isolation valves are added. if yes then is there any clause or section in ASME 31.3 or API which states any requirement. If no stress analysis is required we need to convince the client with some concrete reasons. Help reqd on the above issue.





RE: Stress Analysis for existing PSV systems
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RE: Stress Analysis for existing PSV systems
RE: Stress Analysis for existing PSV systems
RE: Stress Analysis for existing PSV systems
Sections in B 31.3 are part 5, sections 319 to 322.
The actual impact is dependant on your actual design and piping configuration, but you're potentially adding some significant weight and mods to the piping in order to squeeze two more valves in which will probably have an impact on the systems, including the original process pipework and the vent pipework. Sounds like you don't want to do the analysis but without doing at least one or two "worst cases" it is very diffiuclt to prove a negative. If you pick two or three out which look like they could have the biggest impact, study / analyses those and then make your decision, at least you have some proper data to use. Probably not what you wanted to hear, but many incidents have been caused by retrofit engineering occurring piecemeal and everyone being able to justify not doing things until the cumulative effect overwhelms the, probably quite corroded, strength of the system.
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