Purpose of relief valves?

• A. Prevent system damage and automatically release excess pressure
• B. Control flow rate
• C. Seal leaks
• D. Cool the system

Answer: (A)

Relief valves are safety devices that protect equipment from overpressure by automatically releasing excess pressure when the system pressure exceeds the valve’s set point. If something causes pressure to rise—like heat input, a blocked line, or a pump issue—the valve opens just enough to vent the excess and then closes again once the pressure returns to normal. This prevents damage to vessels, piping, and other components and helps keep personnel safe.

They’re not meant to control flow rate during normal operation—that’s the job of flow control valves. They also don’t seal leaks or cool the system; sealing leaks isn’t a relief valve function, and cooling is handled by heat exchangers or cooling equipment.