Novel sensor–actuator device for early detection of fire

A new design concept of heat detectors, which introduces an ability to actuate various fire suppression systems, is described for the detection of early stage of fire. The device has been based on NiTi shape memory alloys. Application of such NiTi shape memory alloys in novel sensor–actuator allows not only a unique autonomous detection of fire at its early stage but also provides an opportunity to actuate fire suppression systems. Four basic set actuation temperatures of NiTi alloys 55 ± 5, 80 ± 5, 93 ± 5, and 110 ± 5 °C have been used in the proposed design. X-ray diffraction (XRD), energy-dispersive X-ray diffraction (EDX) and scanning electron microscopy (SEM) techniques have been employed for morphology characterization of the heat-treated NiTi samples. Compliance testing to the requirements of the appropriate standards revealed that the novel heat detector based on NiTi shape memory alloys with actuation temperature of 80 ± 5 °C complies with the requirements of the standards for the Class B type heat detectors. The study revealed that high sensitivity combined with actuation function provides a unique opportunity for early fire detection at maximum relative humidity of 98%. The detector is capable of sustaining impacts of up to 4 g-force of 2–50 ms duration. It is also capable of sustaining vibration from 0.5 to 200 Hz with acceleration of 4 g. The reliability investigation of the heat detection based on NiTi shape memory alloys is now in progress.