Optical smoke detectors have a light emitting diode along with a receiver.The detection principle is normally dependent on light scattering, the effect of smoke is to scatter light from the transmitter to the receiver.
Optical chamber smoke detectors in accordance o BS EN 54-7 have an adequately broad range of response to be appropriate for most applications in which a smoke detector is suitable.
Where is the best place to install Optical Detectors?
Optical smoke detectors are responsive to visually dense smoke, however, are less sensitive to the tiny particles located in clean-burning fires that leave little visible smoke. Detectors that use the principle of light scatter are more responsive to light coloured smoke; very dark smoke, by classification, absorbs light as opposed to scatters it, but will be readily detected by a smoke detector that activates on the principle of obscuration (e.g. an optical beam type detector).
One of the potential risks on escape routes and stairwells is visible smoke, which can obscure the visibility of the route and of exit signs. Optical smoke detectors are thus appropriate for use on escape routes since they detect visible smoke and might operate before the escape route becomes impassable.
Optical detectors are more inclined to generate false alarms from cigarette smoke and water vapour; ionization chamber detectors have a tendency to give false alarms if positioned in areas whereby fumes from cooking processes, (e.g. burnt toast) can happen, for example, spaces close to kitchens.