Analyzing smoke alarm response to flaming fires using the fire model JET

Abstract

An algorithm that calculates the time dependent smoke concentration in a fire-induced ceiling jet within a smoke layer and algorithms for predicting the response of photoelectric smoke alarms, both of which are part of the computer model JET, are examined using three different fires in a small room. The objectives of this analysis are to test the ceiling jet smoke algorithm and understand the limitations of analyzing signals from photoelectric smoke alarms located in the ceiling jet to estimate fire size and thereby support decision making by emergency responders. The analysis is restricted to flaming fires that produce turbulent plumes and can be represented by axisymmetric point sources. Two different smoke yields from the literature are used to obtain ceiling jet smoke density from JET. Depending on the value of the smoke yield used, the predictions of JET follow or do not follow the photoelectric smoke alarm signals. This suggests that additional information about how smoke yields are measured or that a better calibration technique is required in order to accurately model smoke alarm response.