Bulletin of Japan Association for Fire Science and Engineering
Online ISSN : 1883-5600
Print ISSN : 0546-0794
ISSN-L : 0546-0794
Volume 3, Issue 2
Displaying 1-9 of 9 articles from this issue
Paper
  • Tsuruji OKAWA, Tadashi WACHI
    1954 Volume 3 Issue 2 Pages 33-35
    Published: 1954
    Released on J-STAGE: April 10, 2015
    JOURNAL FREE ACCESS
    With nine different type fog nozzles, discharge capacity, effective range, size of particles, distribution of particles and etc. were measured at the nozzle pressure ranging 50~300psi.
    The adjustable type nozzle had the advantage of the nonadjustable type because the former was possible to produce any desirable fog pattern.
    We depend on the future development of suitable type nozzles for the experiments of the nozzle pressure more than 300psi.
    The fog particles was much smaller size than expected, and it was afraid they were blown off by rising air current at the fires.
    Download PDF (490K)
  • Yohei KUMANO, Kazuyoshi ISHIZAKA
    1954 Volume 3 Issue 2 Pages 36-38
    Published: 1954
    Released on J-STAGE: April 10, 2015
    JOURNAL FREE ACCESS
    To determine the safe distances in operating hand extinguishers against electrical equipments or live lines, the disintegration characteristics of solid stream from extinguisher nozzles were investigated by high speed flash photography and also by measuring electric current passing through the streams directed on a metal plate at 1,500 V D.C..
    The conclusion is as follows : (1) The higher the discharge pressure (or discharge velocity) the longer the range beyond which the solid stream breaks up into droplets.
    (2) The pressure being equal, the stream from large nozzle with smooth convergence will preserve continuity for greater distance.
    (3) When pump tank extinguisher, equipped with 4mm good nozzle is operated strongly, the discharge stream momentarily preserved continuity and carry current for as far as 1.3m.
    Download PDF (505K)
  • Kazuo AKITA
    1954 Volume 3 Issue 2 Pages 39-41
    Published: 1954
    Released on J-STAGE: April 10, 2015
    JOURNAL FREE ACCESS
    Temperature distribution in wood heated by hot air which has constant temperature (150°C-190°C) is measured by the thermocouples and electromagnetic oscillograph or galvanometer.
    The conclusion was as follows : (1) Temperature distribution in wood is given approximately as the solution of differential equation, which does not contain the exothermical term by decomposition heat of wood, δθ/δt=k(δ2θx2).
    (2) Heat transfer coefficient at the surface is increased gradually with the increase of the fluid temperature.
    (3) Before ignition, temperature in wood is decreased as the distance increases from the surface. This fact shows that the breadth of wood has only a slight effect upon the time lag of ignition.
    Download PDF (300K)
  • Takashi SEKINE
    1954 Volume 3 Issue 2 Pages 42-44
    Published: 1954
    Released on J-STAGE: April 10, 2015
    JOURNAL FREE ACCESS
    The vertical distribution of mean wind velocity was observed, using several Robinson small cup anemometers, in the lower layer over three places in Tokyō.
    From the results, the vertical distribution of wind velocity was fitted to the logarithmic law as follows :
    U(Z)=(U/k) loge ((Z-d)/Z0)………(1)
    where U, k, Z0 and d denote the friction velocity, Kármán’s const. 0.45, roughness parameter and zero plane displacement (d was chosen to give the best fit in wind profile). The values of d and Z0 are observed.
    Then, the vertical diffusion coefficient (Kz) is given by (2), from Prandtl’s theory on the turbulence mixing.
    Kz=kU (Z-d)………(2)
    The calculated values of Kz was the order of 104cm2/sec, for Uav varying form 3.6m/s to 6.4m/s at height from the ground 10m.
    Download PDF (247K)
  • Kunio KAWAGOE
    1954 Volume 3 Issue 2 Pages 45-47
    Published: 1954
    Released on J-STAGE: April 10, 2015
    JOURNAL FREE ACCESS
    A concrete block room (area 3×3m, height 2.5m) was used for 4 times experiments on which the combustion speed, the flame temperature and CO2, O2% in dry exhaust gas were measured. Results were as follows : 1) The maximum temperature was about 800~900°C.
    2) The rate of excess air was about 1.0.
    3) The average combustion speed was compared with the theoretical value explained in the same title (1).
    Download PDF (230K)
  • T. KUROKAWA, T. KANESAKA, M. FUDEUCHI
    1954 Volume 3 Issue 2 Pages 48-50
    Published: 1954
    Released on J-STAGE: April 10, 2015
    JOURNAL FREE ACCESS
    In this report the loss of head in fire hemp-hoses due to friction, leakage and repaired trails is treated. The results are follows : 1) The coefficient of frictional loss by new hoses is
    λ=0.040-(6/1,000)υ, where υ=mean velocity in hose, m/sec.
    2) The effects of leakage upon λ are expressed by using (1+q/Q) λ instead of λ, where q=quantity of leakage m3/sec, Q=quantity of discharge m3/sec.
    3) The effects of repaired trails, and ages of hose
    Y are expressed by Δhυ=ζ(υ2/2g), ζ=0.014(n+SY m)/υ where n,m=number of trails, S=factor on proficiency of repair, υ=mean velocity.
    Download PDF (293K)
  • Tosirô KINBARA
    1954 Volume 3 Issue 2 Pages 51-54
    Published: 1954
    Released on J-STAGE: April 10, 2015
    JOURNAL FREE ACCESS
    Velocity of propagation of combustion along the surface of inflammable liquid was measured at various temperatures. When liquid temperature is comparatively high, combustion propagates through vapor-air mixtures floating above the surface of the liquid. But as the temperature is lowered, the ratio of the density of vapor to that of air approaches to lower limit of ignition and a temperature is attained at which the vapor is so lean that the combustion can no longer propagate through this layer of vapor-air mixture, and the “combustion after vaporization” begins. At this stage, the liquid surface close to the flame front is heated to vaporize by the flame itself and after the vapor density at the layer adjacent to it attains to the lower limit of combustion, the flame propagates to this layer.
    The boundary temperature between these two stages of propagation was considered to be a flash point and was measured with various liquids.
    Download PDF (427K)
  • Shunsaku NAKAUCHI
    1954 Volume 3 Issue 2 Pages 55-57
    Published: 1954
    Released on J-STAGE: April 10, 2015
    JOURNAL FREE ACCESS
    Rate-compensation type fire detector has not any of the drawbacks of the rate of rise type and the fixed temperature type ones. To my knowledge, however, there is no bulletin published of the theory of its operation.
    With an object of giving guidance to the designing of this type of fire detectors, the fundamental theory is introduced.
    Fundamental equations are given in this report representing the operation of the detector in the following two cases : 1. When the detector is heated by the air which rises in temperature at constant rate.
    2. When the detector is heated by the air which rises in temperature discontinuously by a certain value at t=0.
    Download PDF (303K)
  • H. YAMANOUCHI, K. OKAJIMA, K. KAWAGOE, Y. MATSUURA
    1954 Volume 3 Issue 2 Pages 58-62
    Published: 1954
    Released on J-STAGE: April 10, 2015
    JOURNAL FREE ACCESS
    In each test, several kinds of material test pieces and machine parts were tested and the total numbers were about 72. A small size of turret-lathe, was tested also. We have observed the damages in quality and dimension, the strains, the heating temperature etc. by the fire flame, radiation heat and by the fire-extinguishing water. For temperature measurements, 12 thermocouples, 11 seger cones (798°~1200°C), 3 thermopaints (350°~450°C) and 5 tempalags (510°~899°C) were used. Max. room-temperature were 630°~880°C., max. articles-temperature 593°~704°C and the room-temperature >500°C were kept for about 10~13 minutes.
    In our fire-test the iron and steel castings, steel forgings and rolled steel materials were least damaged and can be considered the possibility of resurrection with a little working-up, but the heat-treated articles such as springs, tools, ball bearings, and the non-ferrous materials were largely damaged in the quality and dimension. Particularly it is necessary to pay attention to prevent the corrosion increase on the iron and steel parts of the machinery after the fire.
    Download PDF (659K)
feedback
Top