Test media for testing of PSV installed in gas service 2

[Magnar]

Sorry if this question have been asked before, but couldn't find anything.

I have a question if PSV should be tested with Nitrogen or with Air.
A new test workshop for recalibration of PSV shall be made on an installation on the Norwegian Continental Shelf covered of covers by European regulations. The questions shall we use Nitrogen or is it acceptable to use air. I do not find anything in the standards that gives limitation for the test media except valves installed in gas shall preferable be tested in gas like: "Air or Nitrogen can both be chosen" and "air or other suitable gases”. Pressure up to Ansi 2500 on inlet flange.

Anyone that can give pluss and minus for Nitrogen vs Air and maybe where I can find the regulation either or?

 

[The Obturator]

Presumably you'll be testing to API-527 which is virtually the only known standard for seat tightness testing. API-527 advises to use air (or nitrogen) to test Pressure-relief Valves on compressible fluid service (and water for non compressible service). I have seen some users specify nitrogen only, but this is not mandated anywhere that I know nor is it any better, or worse to use as a test medium.


*** Per ISO-4126, the generic term
'Safety Valve' is used regardless of application or design ***

*** 'Pressure-relief Valve' is the equivalent ASME/API term ***

 

[Magnar]

Absolutely correct, seat test according to API 527.
The company have about 35 offshore platforms and it's 50/50 using Nitrogen or Air as test media. Now a new platform is building a new test workshop for PSV and ask "what media do you recommend?". No standards point on a specific test media.

So again: Anyone that can give pluss and minus for Nitrogen vs Air as test media for PSV? Because this ends up with either or

 

[Muhammad Talha Khayyam]

Hello I have a question: Can we do pop testing with water of a PSV installed for Gas service? I have tried to search for this in API standards but havent found anything. Kindly answer this if anyone knows. Thankyou?

 

[The Obturator]

No. You won't find it in any standard or procedure because it is simply bad practice.


*** Per ISO-4126, the generic term
'Safety Valve' is used regardless of application or design ***

*** 'Pressure-relief Valve' is the equivalent ASME/API term ***

 

[JAlton]

National Board Inspection Code, Part 4, Sec. 4.6.1 TEST MEDIUM AND TESTING EQUIPMENT
Valves marked for steam service, or having special internal parts for steam service, shall be tested on steam. Valves marked for air, gas, or vapor service shall be tested with air or gas. Valves marked for liquid service shall be tested with water or other suitable liquid.

ASME Sec XIII, Para. 3.6.3 Set Pressure Tests
3.6.3.1 General
(a) Each pressure relief valve to which the Certification Mark and appropriate Designator is to be applied shall be tested by the Manufacturer or Assembler to demonstrate
the valve’s set pressure.
(b) Set pressure tests for pressure relief devices shall be conducted using the test fluid specified in Table 3.6.3.1-1.

UV - Gas or vapor - Test Fluid: Air or other suitable gas
UV - Incompressible fluids (liquids) - Test Fluid: Water or other suitable liquid

JAC

 

[JAlton]

2-3 TYPES OF DEVICES
2-3.l Reclosing Pressure-Relieving Devices pressure relief valve {PRV): a pressure relief device
designed to actuate on inlet static pressure and reclose after normal conditions have been restored. It may be one of the following types and have one or more of the following design features:

relief valve: a pressure relief valve characterized by gradual opening that is generally proportional to the increase in pressure. It is normally used for incompressible fluids.

safety relief valve: a pressure relief valve characterized by rapid opening or by gradual opening that is generally proportional to the increase in pressure. it can be used for compressible or incompressible fluids.

safety valve: a pressure relief valve characterized by rapid opening and normally used to relieve compressible fluids.

JAC