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When Are Psv Recalculations Required?


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#1 ryn376

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Posted 13 March 2019 - 02:03 PM

We have a client in the U.S. who has purchased a facility and is telling us that they do not need to have PSV calculations redone for some parts of the process. We are of the opinion that recalculations are required because the process is changing. The previous owners made fermentation broth with algae in water and the new owners are making fermentation broth with bacteria in water. A lot of equipment is being reused. Flows, pressures, and temperature may or may not be changing. The client has asked for a code or standard that says they are required to redo the calculations.

 

Does anybody know of a U.S. code, standard, regulation, etc. that specifically states when recalculations are required? I cannot find anything concrete in API 520, 521 or ASME VIII, but I'm sure I missed it somewhere.

 

Thank you.



#2 Bobby Strain

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Posted 13 March 2019 - 03:08 PM

You should ask your client to direct you as such in writing. Then you should find a way to check the need and bill the client. Or refuse the client request. Politely.

 

Bobby



#3 flarenuf

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Posted 14 March 2019 - 04:54 AM

how much would it cost your client in litigation and rebuilding the plant after a disaster  compared to checking a few PSV's?



#4 ryn376

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Posted 14 March 2019 - 06:00 AM

We have told them that we need to redo them, they say "we are overthinking it" and wish for us to cite regulation. Does anybody have any references?



#5 latexman

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Posted 14 March 2019 - 06:12 AM

Unfortunately, the Management of Change section is weak in OSHA PSM.  High quality companies recognize this and do the right thing.  I recommend you run, don't walk, away from this client.



#6 latexman

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Posted 14 March 2019 - 07:24 AM

Why not show them.  Pick 1-3 reliefs where it is obvious to your expert that things have changed.  Redo those relief records, and compare them to the old records in detail.  Besides process changes, there may be Code and relief sizing technology changes too.  It will probably be eye opening to both sides.  If the client won't sponsor it, talk to your sales and marketing folks, they may sponsor it as a marketing/sales tool on this client and others.



#7 Sharma Varun

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Posted 14 March 2019 - 10:40 PM

We have a client in the U.S. who has purchased a facility and is telling us that they do not need to have PSV calculations redone for some parts of the process. We are of the opinion that recalculations are required because the process is changing. The previous owners made fermentation broth with algae in water and the new owners are making fermentation broth with bacteria in water. A lot of equipment is being reused. Flows, pressures, and temperature may or may not be changing.

 

 

Well before doubting the client please detail out your query, you are saying client do not need to have PSV calculations for some parts of process.

Please check the relieving scenarios for these particular parts, have they changed? Say if only fire case is relevant for a vessel which is retained with same liquid levels as in past & there is no change in latent heat of vaporization, you need not carry out PSV adequacy. I am basically involved in refining and have no idea about your process but it may happen that by just changing algae/ bacteria you might not be adding any credible pressure source.

 

 

 

 

The client has asked for a code or standard that says they are required to redo the calculations.

 

Does anybody know of a U.S. code, standard, regulation, etc. that specifically states when recalculations are required? I cannot find anything concrete in API 520, 521 or ASME VIII, but I'm sure I missed it somewhere.

 

Thank you.






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