Now FM-approved FireChek® thermal shutoffs with resettable memory shape alloy can be used to automatically shut down a pneumatic control system when a nearby fire occurs, or when the ambient temperature reaches 135, 150, or 165°F. The testability and reset ability of the FireChek makes it a preferred choice over emergency isolation valves that rely on fusible links or plastic burn-through tubing.
When the FireChek senses excessive heat from a nearby fire, it immediately closes the air supply line preventing the air from feeding the fire. It simultaneously vents the spring return actuator to allow the return to fail-safe. The FireChek triggers quickly, securing pneumatically operated process line valves in their fail-safe position for both on/off and throttling applications. Because FireChek responds to heat, not flame, it offers dramatically improved protection compared with conventional plastic tubing burn-through.
The shape memory element senses the ambient temperature and, through a phase induction change, rapidly produces the force and motion to trigger the FireChek. The element is 100 percent reliable because the shape memory effect is intrinsic to the alloy. Shape memory alloys have performed successfully for many years in military, industrial, and consumer product applications.