Bulletin of Japan Association for Fire Science and Engineering
Online ISSN : 1883-5600
Print ISSN : 0546-0794
ISSN-L : 0546-0794
Volume 11, Issue 1
Displaying 1-5 of 5 articles from this issue
Paper
  • Kojiro KAMEI
    1961 Volume 11 Issue 1 Pages 1-6
    Published: 1961
    Released on J-STAGE: December 04, 2013
    JOURNAL FREE ACCESS
    Conflagrations are defined in this study as “fires extending over a considerable area and destroying numbers of houses-say more than 50 houses and 3,300m2 in floor-area burnt down”.
    Table Nos. 1 and 2 list 14 conflagrations occurring in Japan since March 1934, which involved 500-4,000 houses respectively, The tables show the conditions at the time the fires broke out, such as wind velocity, temperature, humidity, and duration of strong wind blowing through the fires.
    The 14 conflagrations have been analyzed from three angles as follows :
    A) Statistical approach
    The conflagrations were disposed to begin in Kagoshima prefecture-the southern part of Japan-in the winter season, and to end in Hokkaido early in the summer season, gradually going northeastwards. Seasonally March and April had the highest fire frequency during the year.
    A regional deviation of conflagration frequency was also found ; the prefectures in Tohoku facing the Japan Sea such as Aomori Akita, etc. were especially focused on with wide-spreading fires.
    B) Weather conditions
    1) Temperature : Atmospheric temperature had little effect on the occurrence of the conflagrations under review, but fires occurring in a foehn were always aggravated by the warm wind.
    2) Humidity : Atmospheric humidity has a vital relation to the outbreak of a fire, but has relatively little effect upon developing it into a conflagration. Table 1 shows that ten of the conflagrations had a rather high humidity from 42~84 percent at the time the fires started, and that the remaining four were assisted by a low humidity from 23~33 per cent.
    3) Atmospheric pressure : Atmospheric pressure is liable to cause the foehn in the districts facing the Japan Sea under certain conditions of typhoon in connection with the geographic features, promoting conflagration-potential of a fire happened to exist at such time.
    4) Wind velocity : Wind velocity is a decisive factor in spread of fire. The duration of the high velocity wind which contributed to the fire spread varied from 2.5 to 26 hours in the 14 conflagrations listed. In the case of Iida City conflagration, a gust of wind due to the geographical features was considered one of the serious factors in developing the fire.
    C) Spot-fires
    If there were no spot-fires, there could be fewer expectation of conflagrations. The author tried to take actual examples of spot-fires which had effect upon fire spread, and made Fig. 2 showing the correlation of the distance of spot-fires with the wind velocity in the 14 conflagrations which were effectively developed by spot-fires.
    Fig. 2 shows that when wind velocity was higher than 15 metres per second (Group “A” in the Fig.2), the areas within 99 metres from the main fire were most frequented by spot-fires, and that when the wind velocity was lower than 15 metres per second (Group “B” in the Fig.2), the spot-fires were mostly distributed over the areas from 100~299 metres distant from the main fire.
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  • Takeo KANASAKA, Kinzo HIROSAWA
    1961 Volume 11 Issue 1 Pages 7-9
    Published: 1961
    Released on J-STAGE: December 04, 2013
    JOURNAL FREE ACCESS
    Suggested by the small explosive accident occurred from the mixture of barium azide (used as a getter) and carbon tetra-chloride at a vacuum radio tube factory, this research was made through the experimental testing of :
    1. First, determining the explosive sensitivity of the mixture of barium azide and carbon tetrachloride on a fall hammer tester.
    2. Determining the explosive sensitivity of barium azide itself
    Then, observing these both sensitivities in comparison.
    4. Finally, repeating the same testing on the mixture of barium azide with other various chlorine compounds,
    to know the possible danger of mixing barium azide with carbon tetrachloride eventually for the sake of preventing the accidents of this kind.
    In result of the experiment, the following points were made clear.
    1. Barium azide increases its explosive sensitivity by impact remarkably when mixed with carbon tetrachloride, more than when it was alone.
    2. Barium azide tends to explosion also with other particular chlorine compounds, not only carbon tetrachloride. The more the content of chlorine the larger this explosive danger is. On the contrary, the mixture with the compound of less chlorine content, such as monochloro benzene, invites no ignition or explosion.
    3. The mixture of barium azide and carbon tetrachloride obtained through soaking for 40 hours and letting the latter volatilized afterwards show little difference in the explosive sensitivity, compared with that of barium azide itself.
    4. This explosive reaction of the impact-given mixture of barium azide and carbon tetrachloride is considered to ensue from another explosive reaction occurred by the reaction of metallic barium which came out of barium azide with carbon tetrachloride.
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  • Syoichi HOSHINO
    1961 Volume 11 Issue 1 Pages 10-12
    Published: 1961
    Released on J-STAGE: December 04, 2013
    JOURNAL FREE ACCESS
    This essay consist of several items as follows ;
    1. A study on the testing method of fire protection power of various roofing materials and construction.
    2. Fire protection power of galvanized iron as roofing material overlayed on various materials.
    3. Fire protection power of asbestos cement board roofing overlayed on various materials.
    4. Fire protection power of aluminum roofing.
    5. Combustibility test of glass fibre reinforced polyester corrugated roofings.
    6. Combustibility test of steel wire mesh reinforced polyvinylchloride corrugated roofings.
    7. Combustibility test of polyethylen and acryl resins as roofings.
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  • Minoru HAMADA, Yoshiyasu ISAWA, Kenichi USUI
    1961 Volume 11 Issue 1 Pages 13-20
    Published: 1961
    Released on J-STAGE: December 04, 2013
    JOURNAL FREE ACCESS
    HOKKAIDO Prefectural Office and each municipality in HOKKAIDO committed fire risk investigation and fire scheme of each city to Japan Fire Protection Science Association. We handled eight cities ; OTARU, YUBARI, KUSHIRO, OBIHIRO, RUMOI, TAKIGAWA, MURORAN and KITAMI since June, 1957.
    The fire risk investigation and fire scheme consist of the following process.
    First, we ask the municipality to offer the necessary basic data of her fire protection, and we investigate the real state of the city, namely, the topography, the building details, the building coverage, the water supply, the fire brigade, the fire record and other fire protective facilities on the spot.
    Then, on the basis of these data, we calculate the present fire risk of the city, according to “Hishida’s Theory of fire risk calculation”.
    Secondly, we made the several plans to decrease the fire risk, and calculate the expectant low risk with the possible expenditure.
    The details of the results are exemplified by tables in the latter part of this paper.
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  • Yorio YAZI
    1961 Volume 11 Issue 1 Pages 21-25
    Published: 1961
    Released on J-STAGE: December 04, 2013
    JOURNAL FREE ACCESS
    In previous report, when the writer carried out the extinguishment test on kerosene fire by water spray containing emulsifier, the efficiency of extinguishment was influenced in larger degree by the pressure of spray discharge than emulsifier.
    Then, extinguishment tests on kerosene fire were held varying the pressure of spray discharge. If the minimum quantity of spray discharge that extinguishes kerosene fire in time of 1~2 seconds is selected under the condition that the pressure of spray discharge is constant, the efficiency of extinguishment becomes maximum.
    At the discharge pressure of spray more than 15kg/cm2, there is not much change in the time required for extinguishment of fire.
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