Study on the Response Characteristics of Smoke Detectors Based on the ISO 7240-7 Smoldering Cotton Fire

Abstract

In this study, a smoldering cotton fire test was conducted in accordance with ISO 7240-7 to analyze the smoke/aerosols and combustion products that occur during a cotton fire that are crucial flammable components of multi-unit dwellings. The results of the smoldering cotton fire experiment comparing ODM and ASD based on the concentration standard of 15 %/m, which are the operating concentrations of the fire detection of type-2 smoke detectors, indicated a delay of approximately 2∼4 min in the ASD fire detection time. In addition, in the case of the smoldering fire, the CO concentrations appeared to be 37 ppm and 62 ppm at the ASD1,2 fire detector operating concentrations, resulting in high concentrations of combustion gas. Furthermore, in the case of a smoldering fire rather than a flame fire, despite a large amount of smoke/aerosol and gas owing to incomplete combustion because of the lack of buoyancy, it did not flow into the smoke detector chamber and was not distributed on the ceiling; this required a long time to detect the fire. Accordingly, smoke detector operation tests for various smoke/aerosols must be conducted in Korea to meet the international standards of firefighting technology.