This Control Devices ST25-1A200 ASME safety valve has a brass body, a 200 psi relief pressure, a 1/4" male NPT threaded inlet connection, and a stainless steel pull ring for manual pressure relief. The valve's brass body, brass valve seat, and the zinc plated steel spring resist corrosion and can be used in operating temperatures up to 250 degrees F. The preset relief pressure is accurate to within +/- 3 percent and a silicon O-ring provides a leak-proof seal to within +/- 10 percent of the relief pressure. This safety valve is American Society of Mechanical Engineers (ASME) safety rated and displays the UV mark for pressure vessel safety valves. It also displays the NB mark for certification in accordance with NB-501, National Board Certification of Pressure Relief Devices. This safety valve has a 178 cubic feet per minute (CFM) flow rate and is suitable for low capacity pressure relief applications such as in home construction air compressors.

Relief valves remove excess pressure or vacuum from a system. The valve openings allow fluids or gases to escape to decrease pressure, and then close once the valve reaches the reseating pressure limit. They also relieve excess vacuum by opening to release a gas into the system and then closing after it reaches its low-pressure limit. Some relief valves have an adjustment mechanism to set the pressure where the valve opens, making it suitable for various applications. Relief valves are rated according to the volume of liquid or gas that can flow through them and the material that the valve is constructed from must be suitable for the fluid or gas, which may be corrosive or at an extreme temperature, in which it operates. Relief valves are used in a variety of applications, such as air compressors, petrochemical and chemical manufacturing, natural gas processing, and power generation.

Control Devices manufactures valves and other flow control devices. The company, founded in 1963, is headquartered in Fenton, MO.