Citation

Heskestad G, Newman JS. Fire Safety J. 1992; 18(4): 355-374.

Copyright

(Copyright © 1992, Elsevier Publishing)

DOI

unavailable

PMID

unavailable

Abstract

Experiments have been carried out to investigate the efficacy of signal cross-correlation techniques to provide early detection of fire. Cross-correlations were of the form and , where A, B and C were signals from various sensors and denotes averages of signal products over a correlation time interval, [tau]c, extending from present time into the past. All signals were referenced to their baseline averages extending over a time interval, [tau]B, into the past. Tests were conducted in a room, quiescent or highly ventilated, using fire sources modeled on the test fires of European Standard EN54. Various sensors responded to airborne pyrolysis and combustion products. Two complementary cross-correlations, and 2[middle dot][Delta]T greater than , were shown (with [tau]B selected in the range 100-250 s and [tau]C selected in the range 10-25 s) to be equivalent to a much more sensitive detection system than implied by the limits of the most sensitive EN54 class, where [Delta]CO and [Delta]CO2 are referenced carbon monoxide and carbon dioxide concentrations, [Delta]ION is the referenced output of a measuring ionization chamber, and [Delta]T is the referenced temperature.