Heat detectors are reliable, robust and usually a superb choice for applications where smoke detection will cause false alarms.
Heat Detectors are available in two types:
Fixed Temperature
Fixed temperature heat detectors are designed to alarm when they detect a set temperature value, usually around 68 degrees Celsius.
Rate-of-Rise
Rate-of–rise detectors monitor for rapid increases in the temperature within the area, but also have a fixed temperature limit which will trigger an alarm if the rate of temperature rise has been too slow.
Heat detectors are not suitable for buildings with a high roof or ceiling, due to their slower activation time. Bear in mind that a heat detector will respond only when a fire is well established and generating high heat output, so the higher the roof level the longer it will take for the detector to activate.