PCV vs UG-126(b) PCV vs UG-126(b) torsani (Mechanical) (OP) 11 Jun 15 14:08 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 RE: PCV vs UG-126(b) TD2K (Chemical) 11 Jun 15 14:16 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.p... RE: PCV vs UG-126(b) EmmanuelTop (Chemical) 11 Jun 15 15:28 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 RE: PCV vs UG-126(b) don1980 (Chemical) 11 Jun 15 18:47 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.