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 ASD<sub>1,2</sub> 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.