The results of this study indicate that the prototype smoke
detector fabricated to combine both the ionization chamber
and the optical scattering chamber functions as expected. The
responses of the two components are similar to the responses
previously measured as separate components. The utilization
of the ratio of ionization chamber signal to optical scattering
signal shows potential for use in the discrimination of
very fine particles, such as those from diesel exhausts, and very
coarse particles, such as mine dusts. The commercial smoke
detector showed adequate response to smoldering combustion,
but did not exhibit good response to flaming fires. However,
the potential for the detector to be insensitive to both very
small particles, such as those from diesel exhausts, because it
operates on the principle of light scattering and to the larger
particles as a result of the flow and filter incorporated into the
detector warrant further test and evaluation under typical mine
conditions.