The XPander Heat Detector utilises an open-web casing which allows air to flow freely across a thermistor which measures the air temperature every 2 seconds. Its microprocessor uses algorithms to determine how fast the temperature is increasing and thus be detected at an earlier stage than with a static detector. A rate-of-rise detector is generally preferred to a static heat detector, unless sharp increases in temperature are part of the normal environment in the area protected by the heat detector.
