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Preliminary Backdraft Experiments.

pdf icon Preliminary Backdraft Experiments. (686 K)
Fleischmann, C. M.; Pagni, P. J.

U.S./Japan Government Cooperative Program on Natural Resources (UJNR). Fire Research and Safety. 12th Joint Panel Meeting. October 27-November 2, 1992, Tsukuba, Japan, Building Research Inst., Ibaraki, Japan Fire Research Inst., Tokyo, Japan, 208-215 pp, 1992.


National Institute of Standards and Technology, Gaithersburg, MD


fire safety; fire research; experiments; deflagration; backdraft; gravity current


Backdraft is defined as a rapid deflagration following the introduction of oxygen into a compartment filled with accumulated excess pyrolyzates. A scenario describing the physical and chemical fundamentals underlying backdraft phenomena is presented. A half-scale apparatus, designed to avoid dangerous over-pressures, is used to obtain data from backdraft experiments. A gas burner supplied a 150 kW natural gas fire in a 1.2 m high, 1.2 m wide, 2.4 m long compartment with a small, 2.5 cm high 30 cm wide, vent at floor level. Significant excess pyrolyzates accumulate in 180 sec, when a hatch covering a 0.4 m high 1.2 m wide vent, centered on a short wall, is opened. A gravity current carries a flammable mixed region to a spark located near the burner on the opposite wall. The rapid deflagration which results upon ignition of the mixed region is the backdraft.