What is the purpose of listing levers on safety valves?

The purpose of listing levers on safety valves is to facilitate manual testing of the valves. This feature allows an operator or technician to operate the valve without the need for the system to be fully pressured or in an active state. By using the lever, the operator can simulate the conditions under which the valve would open during an overpressure event, verifying that it is functioning correctly and releasing at the designated pressure.

Manual testing is vital for safety reasons, as it ensures that the valve can effectively perform its function in a real emergency. Thus, having a lever allows for proper maintenance and assurance of safety systems without compromising the integrity of the overall steam system.

Other options focus on different functionalities that are not the primary purpose of levers. Automatic pressure release pertains to the valve’s inherent design rather than the lever; adjusting valve pressure involves settings that may need calibrated controls, and increasing the lifespan is typically associated with overall maintenance practices rather than a single lever action.