Bench testing of Pilot PSV 2

[Mohammad Saad]

Hi everyone, hope you all are doing well.

I wanted to ask if we can calibrate the pilot PSV (removing the pilot part from the main valve) by connecting its inlet directly to the test bench? Apparently, there seems to be no issue in that but are there any precautions to be taken or code restrictions to keep in mind? The situation is that we have to check/calibrate the pilot PSV but we cannot bring the whole PSV to the testing shop. So we are trying to just bring the pilot part of the psv.

 

[The Obturator]

You can do that, but different manufacturers pilot valves, have different test procedures to let you do this (or not). You may find that a certain volume of test fluid is required to 'push' the internals in the pilot. Also, use the correct test fluid for the application. Having said all that, how are you then sure that the completely assembled pilot operated pressure relief valve will properly function?. How can you be sure that the main valve will actually open?

Important: Most pilot operated pressure relief valves are fitted with field test connections, meaning you can test the pilot valve test pressure while the complete valve is installed on the system. You do this by fitting a pressure source/gauge to the field test connection.

Above all, read and understand the manufacturers test instructions.


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

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

 

[The Obturator]

Read also the guidance in API-576 - Section 6.5 States that you can handle the pilot valve separately with the stated observations. Note a manufacturers instructions may differ to this guidance.


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

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

 

[Mohammad Saad]

Dear The Obturator,
Thank you for your valuable guidance