Development of a Photoelectric Smoke Detector with a Built-in Function to Prevent False Alarms Owing to Humidity

Abstract

In this study, a photoelectric smoke detector with a built-in function was developed to prevent false alarms owing to humidity. Smoke-detector sensitivity characteristics were analyzed through room-scale false alarm experiments and by generating humidity conditions measured using a type approval sensitivity tester. The results showed that when humidity was generated, more light scattering occurred as the humidity flowed into the detector chamber along with the smoke, increasing the smoke concentration of the smoke detector. It was found that smoke concentrations increased at a relative humidity of 85 %RH or higher. The findings confirm that false alarms occur owing to high concentrations of humidity in the summer. False alarms that occur owing to high concentrations of water vapor in summer can be prevented by detecting fires using a humidity + smoke concentration fire-detection algorithm that has been quantified through experiments.