What does a thermometer icon in a fire alarm system indicate?

The thermometer icon in a fire alarm system signifies a heat detector. Heat detectors are designed to respond to elevated temperatures caused by fire. They are often utilized in situations where smoke detectors may not be advisable, such as in kitchens or areas with a lot of dust or humidity, where false alarms from smoke detectors could be frequent.

Heat detectors typically activate when the temperature exceeds a specific threshold or when there is a rapid rise in temperature. The usage of a thermometer icon effectively communicates the type of detection mechanism in place, allowing users to understand that the system will respond to heat rather than smoke or other potential fire indicators.

In contrast, the other options—smoke detectors, carbon monoxide detectors, and temperature sensors—serve different purposes and would typically be represented by different icons. A smoke detector would indicate the presence of smoke, a carbon monoxide detector focuses on dangerous gas levels, and a temperature sensor usually measures ambient temperature without being triggered by defined fire conditions. The differentiation is critical for ensuring appropriate fire protection measures are in place.