Bulletin of Japan Association for Fire Science and Engineering
Online ISSN : 1883-5600
Print ISSN : 0546-0794
Volume 58 , Issue 2
Showing 1-4 articles out of 4 articles from the selected issue
Paper
  • Yoshitsugu AOKI
    2008 Volume 58 Issue 2 Pages 21-26
    Published: 2008
    Released: September 29, 2009
    JOURNALS FREE ACCESS
    Though it is regulated that two evacuation routes are ensured in laws and regulations, it becomes safer of that there were many evacuation routes approach. It is difficult that multiple evacuation routes including the bypass are enumerated, because there are many numbers on the route including the bypass, and the meaningless routes are also contained as evacuation route where the over of 2 degrees also pass the same place. We propose an enumeration method of the effective evacuation routes.
    The set of routes from origin to destination with the bypass can be enumerated by the method of with the series representation which had been proposed. But, there are many nonsense routes for evacuation. We improved one such that excludes the cyclic routes as meaningless routes for evacuation.
    The example for probabilistic evaluation on routes based on the set of got effective evacuation route is shown.
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  • Yoshitsugu AOKI
    2008 Volume 58 Issue 2 Pages 27-32
    Published: 2008
    Released: September 29, 2009
    JOURNALS FREE ACCESS
    On the plan with a straight corridor, we deduce an equation which gives a success probability of evacuation from a given start point.
    As a criterion on building safety, we propose the Min-Max principle that 1) we must evaluate a safety by the minimum probability of success, and 2) we must prefer the plan with maximum value of the minimum probability. Based on the Min-Max principle, we compare the plans with different staircase location.
    It has being recommended that the staircase is located in the double end of corridor. It is proven that the minimum success probability of the staircase plan with the part in the dead end corridor is greater than the one of the plan with double end staircase.
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  • Masataro SUZUKI, Kentaro MITSUYA, Kiyoshi NAGASHIMA, Wataru MASUDA
    2008 Volume 58 Issue 2 Pages 33-39
    Published: 2008
    Released: September 29, 2009
    JOURNALS FREE ACCESS
    The understandings of the critical condition of flame spread over combustible solids are essential for improving fire protection technology. Once the flame loses stability and moves back from the leading edge of the pyrolysis front on the solid surface during flame spread process, the flame spread stagnates, or, more likely ceases, because the unburnt part of the combustible solid loses direct heat transfer from the flame. The obstacle to the quantitative understandings of this critical condition is the complexity of the interaction between solid and gas phases. This work focuses on a portion of this interaction, namely, the effect of vaporized gas on the stability of the spreading flame. A boundary layer diffusion flame on a plate burner is adopted and the effects of velocity profile of the fuel gas ejected from the burner port are investigated. Methane is used as the fuel. The results clearly show the critical condition; the flame is stable only when both the gas velocity at the upstream edge in the ambient airflow and the two-dimensional volume flow rate exceed the critical values, which are 12 mm/s and 46 mm2/s, respectively. It is inferred from these results that the flame stability is simply determined by the gas ejected within the range of 3.8 mm from the upstream edge of the port in the tested condition.
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Note
  • Yuji KURODA, Yasumasa KIKUCHI, Yoshio OGAWA
    2008 Volume 58 Issue 2 Pages 41-45
    Published: 2008
    Released: September 29, 2009
    JOURNALS FREE ACCESS
    We examined the extinguishing properties of foam extinguishing agents for fires involving ethanol-blended gasoline by burning these fuels in a full-scale experiment and then applying foam hose stream using the foam extinguishing agents and foam makers deployed at the pump company. As a result, the following findings were obtained:
    • Fire extinguishing requires longer time as the amount of ethanol contained in gasoline is greater.
    • For ethanol-blended gasoline up to E10, radiation changes are roughly the same as those of ordinary gasoline. There is not any substantial effect of ethanol on fire extinguishment.
    • Fires involving 30 percent ethanol-blended gasoline (E30) require extinguishing time of about 1.4 times longer than gasoline fires do.
    • Fires involving 7 percent ETBE-blended gasoline (ETBE7) can be extinguished using synthetic surfactants.
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