Heat or Thermal Detectors register the increase in temperature caused by a Fire.
a. Fixed Temperature
It triggers automatically when a preset ambient temperature is reached.
b. Rate of Rise
In addition to present trigger temperature, the rate-of rise detectors also evaluate the speed of temperature increase. If the temperature rises faster than the pre-set amount within a specific period, a rate-of-rise detector will trigger an alarm even if the set point trigger temperature has not actually been reached.
c. Rate Compensated
It responds when the temperature of the air surrounding the device reaches a predetermined level, regardless of the rate of temperature rise.