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Author
Fleischmann, C. M. | Pagni, P. J. | Williamson, R. B.
Title
Quantitative Backdraft Experiments.
Coporate
University of Cantebury, Christchurch, New Zealand California Univ., Berkeley
Sponsor
National Institute of Standards and Technology, Gaithersburg, MD
Contract
NIST-GRANT-60NANB1D1168 NIST-GRANT-60NANB3D1438
Book or Conf
International Association for Fire Safety Science. Fire Safety Science. Proceedings. 4th International Symposium. July 13-17, 1994, Intl. Assoc. for Fire Safety Science, Boston, MA, Ottawa, Ontario, Canada, Kashiwagi, T., Editors, 337-348 p., 1994
Keywords
fire research | fire safety | fire science | backdraft | experiments | compartment fires | explosion hazards | gravity current
Identifiers
fire initiation
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.