Fire Safety Science Digital Archive

The photoelectric smoke detector shows different levels of sensitivity to different fire types. The photoelectric detector generally is more sensitive to the gray smoke emitted by smoldering fires, and less sensitive to the black smoke emitted by flaming fires. To improve such a photoelectric detector, the light scattering phenomena by smoke particles have been studied, and numerical simulations of the scattered light by smoke particles have been conducted. Comparing the intensity of the scattered light by the smoke from smoldering fire and the smoke from flaming fire, it was found that their difference ratio is greater in the small angle range of scattering angle but decreases as the angle increases. A detector with the scattering angle of 70 deg. showed an improved response characteristic than a detector with the scattering angle of 40 deg.