Heat detectors are used for additional safety and are helpful in areas where smoke detectors and alarms normally shouldn’t be installed. They are not a substitute for smoke alarms but an additional safety measure.
There are two types of heat detectors, fixed temperature and rate of rise. Fixed temperature heat detectors activate when the heat sensor reaches a “fixed” operating temperature (usually from 120 -140 degrees F). Rate-of-Rise (ROR) heat detectors measure the marginal increase in temperature over time. If a sudden increase is detected the alarm will sound.