PCV vs UG-126(b)

[torsani]

Hi,

Does a globe valve with a pneumatic actuator (like a PCV), controlled by a self-actuated pilot valve (upstream signal) and fail position open meets with requirements of UG-126(b)?

Best regards

Torsani

 

[TD2K]

No.

The exception would be in certain services if such a setup is designed so it was at least as reliable as a pressure relief valve. An instrumented control system that replaces a PSV typically has to be SIL 2 or higher.

http://people.clarkson.edu/~wwilcox/Design/hipps.pdf

 

[EmmanuelTop]

UG-126(b) refers to pilot actuated relief valve, not a pressure control valve. PCV, as per my knowledge, cannot replace relief valve under any circumstances.

https://www.law.cornell.edu/cfr/text/46/54.15-10

Dejan IVANOVIC
Process Engineer, MSChE

 

[don1980]

Pilot valves must be self-actuated. That is, they must be actuated by the pressure in the system and not by external sources such as electrical or pneumatics signals.

Therefore, the valve you describe does not meet UG126b.