control valve seat leakage pressure

[ashishgaud]

I have control valve size 3" X 300# class VI,
what should be its seat tightness pressure and body test pressure.
please know me as earliest as possible

 

[gerhardl]

Whatever the end user specifies. (Ask to what test regulation/papers. Generally to qualify on the market: after the valve specifications the valve is produced to)

 

[NGiLuzzu]

ashishgaud,
when I hear "Class VI", I imply that FCI 70-2 (or equivalent IEC 60534-4) standard is applicable, as this is the one which defines the Tightness Classes for Control Valves (but of course - as gerhardl's post suggests - You should check with Your Customer if this is true in the specific case...).

According to that standard, for "Class VI" seat testing the pressure "shall be the maximum rated differential pressure across the valve plug or 3.5 bar (50 psi) whichever is the least", applied with "air or nitrogen gas at 10°÷52°C (50°÷125°F)".


For body shell test, the usual general rules of industrial valve testing (according to the most common standards, like API 598, ISO 5208, EN 12266-1, etc..) should apply...



Hope this helps,
'NGL
_____________________________________

 

[YBM]

I agree with anegri and would add to look at ASME B16.34 (para. 7.2 which states in part, not less than 110% of the 100F rating, or a gas test at not less than 80psi. (You need to read the entire section.)

 

[TOVmania]

anegri pinpointed the exact practice which most of manufacturers use. Class VI is for the soft seated valve whereas Class V is for the metal seated valve. Most buyers don't care about this though.

 

[sini4s]

Please let me know if the same leakage standard is applicable for on-off type butterfly valve

 

[btrueblood]

Ask the valve manufacturer.