What must be ensured regarding relief valve functionality?

Relief valves play a critical role in maintaining safety in piping systems by preventing overpressure conditions. To function effectively, relief valves must be spring-loaded. This design ensures that the valve will open automatically at a predetermined pressure setpoint, allowing excess fluid to be discharged and thus protecting the system from potential damage caused by pressure build-up.

Spring-loaded relief valves work by utilizing a spring mechanism that holds the valve seat closed until the inlet pressure exceeds the set pressure. At this point, the force from the fluid overcomes the spring’s resistance, allowing the valve to open. This feature is essential for the automatic operation of the valve, which is crucial in emergency situations where manual intervention may not be feasible or timely.

In contrast, while sticky valves and manual operation are considerations, they do not represent the necessary condition for the primary function of relief valves. Disk guides are additional components that can enhance the operation of some relief valves but are not a defining characteristic of all relief valves. Therefore, ensuring that relief valves are spring loaded is fundamental to their functionality and reliability in protecting piping systems from overpressure situations.