PSN cryogenic valves are designed to comply with API 600, BS 6364 standards and Shell MESC 77/306
PSN is capable of pressure testing at temperature from room temperature down to -196C.

All valves except check valves are supplied with extended bonnet with a sufficient gas column length, usually specified by the user, to keep the stem packing exposed only to vapour and not the cold liquid to ensure functional integrity.

Cryogenic testing is conducted by immersing the valve in liquid Nitrogen to cool to the desired temperature which is monitored at a number of locations on the valve, both internally and externally.

Once temperature has stabilized, the pressure test commences using pure Helium or 99% Helium/1%Nitrogen mix as the test medium. Pressure can be increased in increments and seat leakage measured at each increment. Test pressure depends on the rating of the valve and the Cold working Pressure as designated by ASME B16.34 limits the maximum

Valve inspection and test standard API 598.