Wärmemelder

Wärmemelder, or heat detector, is a device used in fire detection systems to sense elevated temperatures and trigger alarms. It is designed for environments where smoke detectors may generate false alarms or be less practical, such as dusty, humid, or steamy areas, or where a slower response is acceptable.

Most Wärmemelder are of two main types: fixed-temperature detectors and rate-of-rise detectors. Fixed-temperature detectors activate when the ambient temperature reaches a preset threshold, commonly around 58°C or 74°C, depending on risk assessments and standards. Rate-of-rise detectors monitor the rate of temperature increase and trigger when the rise exceeds a defined rate, even if the absolute temperature is still relatively low. Some devices combine both principles for increased reliability.

Inside, a sensor element—such as a bimetallic strip, thermistor, or semiconductor element—detects heat and sends a signal to the fire alarm control panel. The units may include local indicators and are typically integrated into building fire alarm systems that operate on standard electrical power, with outputs compatible with panels.

Placement and use: Wärmemelder are commonly installed on ceilings or high walls in corridors, mechanical rooms, and other areas where air movement or emissions could trigger false alarms in smoke detectors. They require regular testing and periodic maintenance, including cleaning and calibration or replacement as recommended by the manufacturer. Standards for heat detectors exist within the EN 54 family in Europe and similar national codes elsewhere.