Which fire detection system is based on heat?

Heat detectors are specifically designed to activate an alarm when they detect the presence of heat that reaches a predetermined threshold. These systems work by identifying a significant increase in temperature, which is often indicative of a fire, making them an essential component for detecting fires in various environments where smoke or gas might not be present initially.

Unlike smoke detectors, which rely on the presence of smoke particles, heat detectors can be particularly effective in situations where smoke may not form immediately, such as in certain industrial applications, garages, or areas with high airflow. Flame detectors, on the other hand, respond to the infrared or ultraviolet radiation emitted by flames, and gas detectors are meant to identify the presence of specific gases rather than temperature. Thus, the primary function of heat detectors, centered around temperature assessment, clearly distinguishes them as the correct answer.