In fire detection, what is the primary role of a heat detector?

The primary role of a heat detector is to sense increased temperature indicative of fire. Heat detectors are designed to respond to changes in temperature that occur when a fire generates heat. They work by monitoring the ambient temperature in an area and triggering an alarm if the temperature exceeds a predetermined threshold which suggests that a fire may be present. This makes heat detectors an essential component in fire alarm systems, particularly in environments where smoke detectors may not be appropriate, such as in dusty or humid conditions.

The other options do not accurately describe the function of a heat detector. Monitoring air quality pertains to devices designed to analyze the presence of various gases or pollutants, which is unrelated to fire detection. Providing audio warnings is a function associated with alarm systems that may include sound components but does not define what a heat detector does. Extinguishing small fires implies an active intervention, while heat detectors are solely for detection and alerting purposes. They do not have the capability to extinguish fires, highlighting their role strictly as sensing devices within fire safety systems.