Quantitative Backdraft Experiments.
Quantitative Backdraft Experiments.
(583 K)
Fleischmann, C. M.; Pagni, P. J.; Williamson, R. B.
International Association for Fire Safety Science. Fire
Safety Science. Proceedings. 4th International
Symposium. July 13-17, 1994, Ottawa, Ontario, Canada,
Intl. Assoc. for Fire Safety Science, Boston, MA,
Kashiwagi, T., Editor(s), 337-348 pp, 1994.
Sponsor:
National Institute of Standards and Technology,
Gaithersburg, MD
Keywords:
fire research; fire safety; fire science; backdraft;
experiments; compartment fires; explosion hazards;
gravity current
Abstract:
This paper focuses on 17 experiments in a 1.2 m by 1.2 m
by 2.4 m compartment. A methane burner, flowing at
either 70 kW or 200 kW, was ignited inside a closed
compartment and burned until the initially available
oxygen was consumed. After the fire self-extinguished,
the burner was left on allowing the unburned fuel mass
fraction in the compartment to increase. After removing
a hatch, covering a 1.1 m wide by 0.4 m high slot
opening, a gravity current entered the compartment. It
traveled across the floor, mixed with the unburned fuel,
and was ignited by a spark near the burner. After
mixture ignition, a backdraft occurred as a deflagration
ripped through the compartment culminating in a large
external fireball. Histories recorded prior to
backdraft included: fuel flow rates, upper layer
temperature, lower layer temperatures, upper layer
species concentrations for O2, CO2, CO, and HC. Data
collected to quantify the backdraft included opening gas
flow velocities and compartment pressures. Results
indicate that unburned fuel mass fractions >10% are
necessary for a backdraft to occur.
Building and Fire Research Laboratory
National Institute of Standards and Technology
Gaithersburg, MD 20899