House Testing Safety Relief Valves

Undetected corrosion, fouling of SRVs, or fouling in the inlet or outlet piping of the SRV can adversely affect the setpoint and the relieving flow rate. Standby equipment that has been improperly specified, installed, or maintained is particularly susceptible to undetected corrosion and fouling. 

PPG Lake Charles was one of the first chemical plants to openly discuss problems that users experience by improperly specifying and testing safety relief valves. Expertise on new safety valves could be obtained from manufacturers sizing methods were documented by various designers and users, but no one published practical SRV testing and SRV corrosion problems. 

Woolfolk became concerned over the adequacy of the SRV test facilities, which were commonly used by many commercial SRV test and repair shops and most chemical plants. The typical test stand consisted of a clamp-down table connected to a compressed air cylinder by a 1/4-inch (0.6 cm) tubing. Woolfolk experimented with surge accumulators for testing relief valves, using a substantial volume of air to mimic actual process conditions. 

Selection of Safety Relief Valve Testing Equipment 

The American Society of Mechanical Engineers (ASME) understands the need for a sufficient volume of gas to properly test a safety relief valve. Until the ASME provides some well-defined guides, a concerned chemical plant may wish to develop its own criteria for 

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