Testing open bonnet safety valves (steam service, > 400 psi) with N2

[Lolek]

Hi all,

I am an Environmental Eng. (ever so umble), so I'm hoping for a bit of help on this forum: can we bench test some PSVs used on steam drums with N2 at ambient temperature? Would I need to correct for temperature differential (CDTP)? After installing, would I need to ask for a life test?

Appreciated

 

[The Obturator]

Lolek. This is an often debated issue. As far as I understand, ASME allows non steam testing where there is no facility available (!). Most bona fide manufacturers will test on saturated steam. There is usually no CDTP for setting on steam. You mention life (live?) test afterwards. If that is available, then this is the best test you can do. Make sure you keep with manufacturers ring settings (often on a plate). Your local plant/code/insurer may have a say in the testing. It is recommended that you speak with the manufacturer about your intentions. Certainly a leak test is not to be done on N2.

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