A134 Smoke detector test-In Press

Chamber experiments of photoelectric optical smoke detector response

Brief:

This study investigates response characteristics of light scattering photoelectric smoke detectors in a test chamber described in UL268, with cotton wick generated fire smoke flowing at a velocity between of 0.5 ms^-1 and 3 ms^-1. Measurements of a ‘base case’ detector, i.e. a detector installed with a sensing chamber, a sensor screen and an outer casing, were compared with those of three other casing configurations: (1) a detector with the sensing element freely exposed; (2) a detector with a sensing chamber; and (3) a detector with a sensing chamber and a sensor screen. It was reported that the amount of fuel burnt, the smoke movement velocity and the detector configuration would have significant influences on the detector response. A detector response constant k for a photoelectric smoke detector in the smoke movement velocitieswas proposed to correlate the optical density attenuation and the changes of detector output signal.

This work forms part of an MEng dissertation. Student: AHY Wong (MEng)

Figure: Experimental set-up