Heat alarms（2 wire heat detectors） are used to identify potential fires that could be large and that could generate much heat. They have a low spurious alarm rate！
The physical definition of the wire heat detectors (no matter 2 wire heat detector or 4 wire heat detector) is:
Set to alarm when ambient temperatures reach a fixed point, typically indicating a fire, fixed-temperature heat alarms are a highly cost-effective solution for many property protection applications. If rapid response to fire is vital, rate-of-rise heat alarms are an ideal solution where rapid temperature increases would only be caused by a fire emergency. Combination heat alarms provide both fixed and rate-of-rise detection. This enables the heat alarm to communicate an alarm to the central control panel prior to reaching its fixed set point for high rates of rise, providing a timely response to both rapid and slow temperature increases.
Speaking of the 2 wire heat detector, it is used in conjunction with the fire alarm system. we also called conventional 2 wire heat detector/alarm.
Hard wired to the main fire alarm panel, conventional smoke, heat and multi-sensor detectors form an essential part of a fire alarm system. When triggered, the conventional 2 wire heat detector signals the main panel, which then activates its other connected components and warns occupants of an emergency situation. Suitable for use with 4, 8 and 16 zone fire alarm panels.