At what pressure should safety valves be set?

Safety valves are a critical component in boiler safety, designed to prevent pressure from exceeding a specified limit. The correct setting for safety valves is at or below the maximum allowable working pressure (MAWP) of the boiler. This is the highest pressure that the boiler and its components are designed to withstand during normal operation.

If the pressure exceeds this limit due to unexpected conditions, the safety valve will open to release steam, thereby preventing potential hazards such as boiler rupture or explosion. Setting the safety valve at this pressure ensures that it functions correctly to protect the entire system.

When safety valves are set at any pressure that is too low—such as the minimum allowable pressure, standard atmospheric pressure, or the operating pressure of the system—they would not function effectively in an emergency. This could lead to catastrophic failures as the pressure could rise uncontrollably beyond safe limits. Thus, safety valves must be calibrated and regularly tested to ensure they are operating at the correct pressure—specifically, the maximum allowable working pressure.