A Sauter mean diameter sensor for fire smoke detection

Abstract

Existing fire smoke detectors utilize the intensity of scattering light as the indicator of fire smokes to trigger fire alarms, but a false fire alarm would be triggered by non-fire aerosols due to their similar concentration characteristics. According to the measurement results of our experiments and related works, the Sauter mean diameters of fire smokes are usually smaller than those of non-fire aerosols. Instead of the smoke concentration detector, a new type of Sauter mean diameter sensor is developed based on dual wavelength technology for fire detection. In order to measure the aerosol samples with different particle size distribution and refractive indices, an extra correction channel is added to reduce the measurement error from 39.1% to 7.61%. The sensor is calibrated by the DEHS (Di-Ethyl-Hexyl-Sebacat) aerosols in different sizes and tested by several typical fire smokes and non-fire aerosols, the results show that the sensor can timely trigger a fire alarm to fire smokes and avoid the false alarm caused by non-fire aerosols. With simple mechanical structure and high accuracy, this sensor improves the performance of optical fire smoke detector with high sensitivity, low-cost and unique ability to resist the false alarms caused by non-fire aerosols.