Citation

Miyama J. Fire Safety J. 1983; 6(3): 157-164.

Copyright

(Copyright © 1983, Elsevier Publishing)

DOI

unavailable

PMID

unavailable

Abstract

In Japan, several thousands of detectors are used in large buildings to protect them from fire. But, to our embarrassment, they are apt to give false alarms. From the results of statistical investigations on twelve buildings, it was confirmed that the light-scattering type is much less likely to give a false alarm than the ionization-chamber type. But, the light-scattering type has a demerit: it is less sensitive to black smoke. Hence, hope was placed on the development of light-extinction type detectors, which would, in theory, be sufficiently sensitive to black smoke.Fortunately, two models of this type were recently developed. One of them uses an infrared light-emitting diode (LED), and the other a visible-light LED. Their sensitivity for several kinds of smoke was measured in a wind tunnel and compared with conventional smoke detectors. From the result of the experiments, it was concluded that both the light-extinction type detectors tested have enough sensitivity for black smoke, and moreover, the detector using visible light has a sensitivity which is the same for every kind of smoke used in the experiments.