What material do most fixed temperature heat detectors use?

Most fixed temperature heat detectors utilize fusible metal as their sensing element. The principle behind these detectors is that they are designed to activate at a predetermined temperature. The fusible metal is selected to melt at this specific temperature; when the surrounding temperature rises to this point, the metal melts and triggers the alarm or activates the fire suppression system.

Fusible metal detectors are commonly used in various applications because they provide a simple and reliable method for detecting heat. Once the metal melts, it often completes an electrical circuit or activates a mechanical switch, allowing for a clear and definitive response to overheating conditions.

In contrast, plastic sensors are not typically used due to their susceptibility to heat and environmental conditions, which can lead to false responses. Copper wires, while they may conduct electricity and be involved in some electronic systems, are not designed to act as standalone heat detection sensors. Thermocouples, while effective for measuring temperature, are more suitable for applications requiring continuous temperature monitoring rather than fixed temperature detection.