pressure test through the manual valve

[Suradach]

Dear Expert
Would it be possible to perform a pressure test on the piping system through the manual valves (Ball valve and Gate valve)?
Do you have limitations in ASME B31.3?
that is problem to us for remove manual valve and fabrication temporary spool to pressure test and flushing

Thank you very much

 

[mk3223]

In the piping pressure test, any "instrument" equipment, including control valve, need to be excluded in the test. but the "piping" valves can be included in the test with the "proper" testing pressure as required.
You may verify if these manual valves in your system are part of the piping to be tested and the pressure rating of the valves are the same as the piping components.

 

[LittleInch]

Not that I can see provided all valves are fully open.

You should never test against the seat of a valve above its design pressure. The body though should be good for 1.5 times the design pressure.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[KevinNZ]

Can we test against the valve seat if system test pressure is less than the class rating of the valve? e.g a 10bar class150 system, test pressure 15 bar.
Will the seat need to be visible to see leaks or would we not care?

 

[LittleInch]

Yes you can.

Yes you need to see the seat so you can see if it is leaking.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[Andrew ONeill]

In practice I do this all the time. The key is that the valve may leak, either via the seat, or the glands on the stem. If you can visually inspect the whole pipe, this isn't a problem. However, if you can't inspect the pipe (say it is underground, or high up in pipe racks etc) and you are going to rely on the pressure reading to indicate a pass/fail, then leaking valves does become a problem.

Andrew O'Neill
Specialist Mechanical Engineer
Australia

 

[0707]

In instrument air systems, screwed connections,sockect weld small diameter piping, you have to do it. I flanged piping systems piping valves are tested separetly and piping systems are tested between blind flanges, this is normal practice done in refining piping systems.