What is considered the most important safety device attached to a low pressure boiler?

The most important safety device attached to a low pressure boiler is the pop safety valve set at 15 psig (max). This valve serves a critical function in maintaining safe operating conditions within the boiler system. It is designed to automatically release excess pressure if it exceeds a predetermined level, which helps prevent potentially dangerous situations such as boiler explosions or ruptures due to overpressure.

Pressure build-up can occur for various reasons, and the pop safety valve provides a necessary fail-safe mechanism. When the internal pressure reaches the setpoint of 15 psig, the valve opens to allow steam or water to escape, thus reducing the pressure back to a safe level. This action not only protects the boiler and associated equipment but also ensures the safety of personnel who are working in or around the boiler.

While other devices, like high limit controls and pressure gauges, play significant roles in monitoring and regulating a boiler's operation, they do not have the same immediate fail-safe function as the safety valve, which acts as the last line of defense against pressure-related hazards.