One type of detection offered is with individual thermostats located strategically within the hazard area. During a fire the thermostat is heated to its factory preset actuation temperature. Upon reaching the preset temperature the electric contacts close and actuate the fire suppression system. When the thermostat cools, the contacts reset to their original open condition.
Another type of detection is with the use of Linear Heat Wire consisting of two steel conductors inside a heat sensitive wiring harness. This wire is usually ran throughout the entire hazard you are protecting. The two internal steel conductors are twisted into a spring loaded normally open condition. When heated to a specific pre-determined temperature, the external conductor jackets will melt causing the conductors to short together and close the circuit; this results in the system discharging.