小型区画を用いたバックドラフト実験 Backdraft Experiments in a Small Compartment Fire

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小型の区画火災実験装置で,バックドラフト発生前後の区画内の温度や酸素濃度の変化傾向などを測定した。この結果,(1)バックドラフトに特有と思われる,天井部付近の温度と酸素濃度の急激な変化傾向が観測できた。つまり,バックドラフト発生前には,火炎の自己消炎に伴い,急激に温度が低下し,酸素濃度は上昇した。(2)バックドラフトの発生直後の開口部からの煙・火炎の噴出状況とファイアボール形成過程をビデオカメラによる連続写真で明確に示した。(3)小型の区画火災実験装置でのバックドラフト発生のシナリオを作成した。<br>(オンラインのみ掲載)

This paper describes results of preliminary backdraft experiments in a 0.85 m high, 0.78 m wide, 1.08 m long compartment, a roughly one third scale residential room. Each surface of the compartment was made with five (for side and upper) or seven (for floor) layers of insulation board to obtain a highly insulated condition. The compartment had a small opening in the middle of the front wall to realize a low-ventilation condition. Interior wall surfaces including the ceiling were partially or fully covered with 12 mm thick wood to simulate a room fire. This wood was the fuel for the fire. A total of seventeen experiments were carried out to find backdraft occurrence conditions for the low-ventilation, highly insulated compartment, and to understand backdraft phenomena. <br>Ten of the seventeen experiments resulted in backdrafts. In this paper, one of these ten experiments, namely Experiment 13, is described in detail to show the backdraft scenario in the compartment. In Experiment 13, backdrafts occurred seven times which is the largest number among the seventeen experiments. Temperature and oxygen concentration measured at 0.15 m below the ceiling showed a very unique change shortly before and after a backdraft. From these experimental results, the backdraft scenario observed in these experiments is as follows: <br>1) Before a backdraft occurs, the compartment fire is much reduced due to the lack of oxygen in the upper layer of the compartment. <br>2) Pre-backdraft phenomena starts. In this process, pyrolyzates from the fuel (wood) accumulate in the upper layer. At the same time, as the fire dies back due to lack of oxygen, the room cools and fresh air from the outside of the compartment is drawn in and mixed into the upper layer. Thus a flammable, premixed gas which can be ignited in many ways is made. Partially burned wood and char on the side and ceiling walls can act as the igniter. This process usually takes a few minutes in the experiments. <br>3) Suddenly, a backdraft occurs. The backdraft consumes all vapor phase combustible products and oxygen in the compartment and makes a fire ball which erupts out of the compartment. After the backdraft the above mentioned pre-backdraft phenomena starts again.

収録刊行物

  • 日本火災学会論文集  

    日本火災学会論文集 48(1), 11-17, 1998-06-30 

    Japan Association for Fire Science and Engineering

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各種コード

  • NII論文ID(NAID)
    10002686114
  • NII書誌ID(NCID)
    AN0018688X
  • 本文言語コード
    JPN
  • 資料種別
    ART
  • ISSN
    05460794
  • NDL 記事登録ID
    4534398
  • NDL 雑誌分類
    ZN1(科学技術--建設工学・建設業)
  • NDL 請求記号
    Z16-105
  • データ提供元
    CJP書誌  CJP引用  NDL  J-STAGE 
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