MSS SP61 Leakage Class

[Beppuse]

Hi
I'm looking for the acceptance criteria for a valve to pass the MSS SP61 seat leakage test. I found that it is 10ml/hr/inch of nominal valve size (I assume inlet) and that it is carried out at 1.1*maximum operating pressure of the valve. is it correct? and what is the fluid used for testing? Water, Helium or Air? Thanks

 

[JLSeagull]

" ... fluid (liquid or gas) pressure no less than 1.1 times
the 100. F (38” C) rating rounded to the next 5 psi
(0.5 bar). At the manufacturer’s option, a gas pressure
of no less than 80 psi (5.6 bar) may be substituted
for the valve sizes ... table ..."

The allowable leakage of each seat closure is 1O ml/hr of liquid or O. 1 standard cu ft/hr of gas per unit of NPS (0.4 ml/hr of liquid or 120 standard ml/hr of gas per unit of DN) under the specified test condition.