Which device signals the alarm system when temperature rises?

• A. Heat detector
• B. Smoke detector
• C. Carbon monoxide detector
• D. Evacuation system

Answer: (A)

Heat detectors are designed to respond to elevated temperatures, either when a fixed temperature is reached or when there is a rapid rise in temperature. Once the preset limit or rapid heat increase is detected, the device sends a signal to the fire alarm system to trigger alarms and notify occupants. This makes it the best choice for situations where smoke may not be present or could cause false alarms, such as in dusty, steamy, or high-heat environments.

Smoke detectors and carbon monoxide detectors sense different hazards—smoke particles and toxic gas, respectively—while an evacuation system is about delivering alarms and instructions to occupants, not sensing heat.