小型区画火災でのバックドラフトと関連諸現象 [in Japanese] Backdraft and its Related Phenomena in a Small Compartment Fire [in Japanese]
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This paper describes results of backdraft and it' s related phenomena in a 0.85 m high, 0.82 m wide, 1.05 m long compartment had 0.24 m high, 0.2 m wide small opening in the middle of the front wall to realize a low-ventilation condition. Interior wall surface including the ceiling were partially covered with 18 mm thick wood to simulate a room fire. The wood was the fuel for the fire. Each outer surface of the compartment was covered with two layers of insulation board to obtain a highly insulated condition. Fifty-six thermocouples were used to measure temperature distribution inside the compartment. Gas concentration in near the ceiling and floor was measured. Oxygen, carbon monoxide, carbon dioxide and total hydrocarbon concentrations were measured. Air ratio and heat release rate were calculated from results of gas concentrations measurement. Wood inside the compartment was detached from the outer walls of the compartment and stood independently on the special tray. Thus the mass pyrolysis rate measured by the electrobalances. To observe the fire growth inside the compartment, the right side wall was made of refractory glass. Thus, backdraft, pre- and post-backdraft phenomena were observed visually. The pre-backdraft phenomenon was self-extinguish and no visible flame. Just after self-extinguishment, mass loss rate decreased rapidly and became about 0.0045 kg/m<sup>2</sup>s. Oxygen concentration was increased and temperature was decreased during no visible flame. When backdraft occurred, rapid temperature increase and oxygen concentration decrease were observed. The post-backdraft phenomenon was persistent flame. L-shaped persistent flame was formed near the opening, a shortcut flow in the flame was easily made due to relatively high flame temperatures.
- Bulletin of Japan Association for Fire Science and Engineering
Bulletin of Japan Association for Fire Science and Engineering 50(1), 31-39, 2000-06-30
Japan Association for Fire Science and Engineering