Development of a Fire Smoke Detector that Satisfies the UL 268 (7th Edition) Fire Sensitivity Tests

Abstract

In this study, we developed a multi-sensor fire detector that satisfies the revised requirements of the cooking nuisance test, polyurethane foam fire test, and polyurethane foam smoldering smoke test of UL 268, and the special program, UL 268 (7th edition), at the Underwriters Laboratories (UL) headquarters in Northbrook, Illinois, United States. The fire detection algorithm was confirmed using the "Research Preliminary Test" program. Our fire detector was evaluated in a dark room with a smoke detector consisting of photoelectric, carbon monoxide, and ionization sensors, and was mounted on a board. In addition, the upper case of the detector is designed to have sufficient space on its top and side surfaces to allow the flow of air and combustion gases. As a result, in the polyurethane foam fire test, the detector triggered an alarm (within 3 min) before the smoke concentration reached 5%/ft (after 3-4 min); thus, satisfying the requirements of the UL 268 polyurethane foam fire test. In the polyurethane foam smoldering smoke test, the detector was operated for 22-26 min before the smoke concentration reached 12%/ft (after 26 min), thus satisfying the requirements of the UL 268 polyurethane foam smoldering smoke test. Lastly, in the cooking nuisance test, the detector was operated for 16-18 min before the smoke concentration reached 1.5%/ft (after 16 min), thus satisfying the requirements of the UL 268 cooking nuisance test. It can be concluded that the results of this study will be useful for the developers of similar products who want to obtain UL certification in the future.