Seat Leakage Control Valve ANSI/FCI 70-2-1991 1

[Instnapp]

Hi All,

With reference to ANSI/FCI 70-2-1991 standard for control valves(unbalanced type), can I perform a seat test(50 PSI) in the direction of flow through the valve or do I need to always test where the flow goes from the top of the valve plug and out as shown in the attached? Would it make a difference if its tested either way?

My understanding is if tested based on the flow direction, I would stand a better chance if its flow to close as the flow would always try to assist the valve in closing.

Thanks and Appreciate your feedback.

 

[SPDL310]

I haven't read that standard that. That being said if you are testing a control valve you would want to test the seat with flow in the direction that it would normally see during operation. The picture you included would be the correct way to test the seat of the valve shown. If you reversed the flow direction you would not be testing the valves ability to shut off flow in normal conditions. You would be testing the valves ability to seal against back flow, which is something you would want to test in a check valve.