PSV ON SITE testing 3

[flinana]

Hi, is there any norm that states that PSV calibration must be tested on site before commissioning?

thanks

 

[The Obturator]

I doubt it, but am not too sure. Maybe others will advise. Some companies may have this in their procedures.

My opinion. You definitely need to do it. This is an end of line, safety relief device. After factory setting, inspection etc., the PRV gets shipped. During transit, the box/crate etc., will be lifted, dropped, knocked, turned upside down, thrown etc. Although robust looking, they can be delicate instruments. One sharp knock can affect the setting up or down. The internals come away from the central axis etc. etc. Normally a pre installation test would verify all is in order.

However what is often ignored is the way the set pressure test is done.
1) The use of the proper test medium.
2) The ring settings being adjusted for test bench test (the nozzle ring will already have been pre set for the PRV intended duty). But this means breaking the seal of the set screw holding the position of the nozzle ring. Get the manufacturer to OK this, as the main setting (ie., adjusting bolt) would have a sealed cap also).
3) Leakage test should also be done.
4) If test is to be done by a In-situ/Hydraulic tool method method, then other precautions apply.

Per ISO-4126, only the term Safety Valve is used regardless of application or design.

 

[flinana]

Thanks, the client has included this in their specification. However, hard to know what is meant by verified by site test.
"The valves shall have a test certificate issued by the manufacturer with inspection authority approval and shall be verified by site test. "

 

[The Obturator]

Taking that you have the manufacturers test and material certificates and a Inspection Authorities test/release certificate, you now need to verify all of that by a site test. This will require its own paperwork to demonstrate to the client.

"Site test" Will mean set pressure and leakage testing to be done (ie. the functions, will it open at set, will it leak ?), specifically for the reasons I outlined earlier. I can't see it any other way for PRV's. This is more or less standard practice now.

Per ISO-4126, only the term Safety Valve is used regardless of application or design.

 

[flinana]

Thanks again, what if we are talking about fuel and oil? Same would apply regardless of the product?

 

[The Obturator]

Please clarify/ Do you mean fuel and oil as the PRV protected fluid ?

Per ISO-4126, only the term Safety Valve is used regardless of application or design.

 

[flinana]

That is correct, fuel and oil pipes and tanks.

 

[The Obturator]

Those PRVs are going to have to be tested on water (as per API/ASME/CommonSense).

So your next comment I guess, will be that you don't have that facility. Testing liquid duty PRV on air/nitrogen is not recommended as you get different results due to the fact that liquid is incompressible. There has been a lot of talk of using corresponding factors for liquid settings against known air settings. There are too many variances with the type of valve, size, pressure etc. etc.

If this is the case, you now best contact the manufacturer with serial numbers with this dilemma.

Per ISO-4126, only the term Safety Valve is used regardless of application or design.

 

[flinana]

Thanks once again, very clear now. We will have to have that facility, its contractual, so, no arguing there.

 

[The Obturator]

You may want to contact JAlton on here (or LinkedIn) for a test bench or advice.

Per ISO-4126, only the term Safety Valve is used regardless of application or design.

 

[JAlton]

PRV Testing prior to installation is NOT a requirement of any Code or Standard that I am aware of. The ASME Code Stamp and Manufacturer or Assembler Seals indicate the PRV has already been tested. In-Service Inspection per National Board Inspection Code is a requirement of "Code" States, refer to NBIC Part 4, Sec 3.2.5.

JAC

 

[The Obturator]

Good advice JAlton. In the case above the client spec required "...verified by site test". A test often done by end users/commissioning people.

Re the NBIC 2019 (National Board Inspection Code - USA), Is this mandatory to follow in USA (or wherever a PRV is NB/UV/V Code Stamped) ?

Per ISO-4126, only the term Safety Valve is used regardless of application or design.

 

[JAlton]

NBIC compliance is mandatory if the Jurisdiction (USA States, Canadian Provinces, a few USA Cities) has adopted NBIC. You can check this on the National Board Website nationalboard.org. Under "Resources" Tab, select NB-370 and enter a Jurisdiction. There are many exceptions. Texas has a boiler law, but not pressure vessels. OK has pressure vessel law, but exempts Oil & Gas Pipelines. I hope this is helpful.


JAC

 

[The Obturator]

Thanks JAlton

Per ISO-4126, only the term Safety Valve is used regardless of application or design.