The fire broke out while a watch cleaning machine was in operation at the close of the last year at a watch store in Shizuoka City. The cause of its fire seems to be the static spark of electric charge stored in the various cleaning liquids and other parts. Then, if the phenomenon of the static carrying charge exits in them, it would be desirable to measure the amount from the point of preventing fire danger. So the amounts of these liquids and other parts have been measured.
Experiments for gasoline, benzine petrol, carbon tetrachloride and trichlorethylene were made by the set which has the valve 1R5 as the amplifier.
The absolute values of carrying charges are maximum in benzine petrol and minimum in trichlorethylene. Then, methods of prevention of fire danger have been established.

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Durisol is one of the lightweight building materials made of mineralized wooden chips and hydraulic cement.
Authors report the results of experimental fire tests for Durisol :
(1) Durisol wall (3cm in thickness) finished with cement mortar (1cm in thickness) passes to Fire-Protective Standard Outdoor II class.
(2) Durisol wall (thickness over 5cm) or block (thickness over 9cm) finished with cement mortar (1.5cm) in fire side and plaster inside, is allowed as wall in Fire-proof Construction.
(3) Structure steel members enclosed by concrete covered with Durisol plate (thickness over 6cm) finished with plaster (2cm), are allowed as beams and columns in Fire-proof construction.

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In this study, the wood boards were heated or ignited by thermal radiation of strong source.
As the source of thermal radiation, D. C. arc was used and light emitted from this source was focused by two elliptic mirrors on the surface of sample board.
In the experiment, the ignition delay and char depth of wood boards, were measured and the effect of intensity of radiation, thickness of sample board, moisture content and heating period to these values was investigated qualitatively.
The main results are as follows :
(1) The char depth of wood boards is increased with the intensity of radiation and heating period, and decreased with moisture content. Also, it is independent of the thickness of sample board.
(2) The char depth of wood boards is decreased in accordance with the order of density of wood.
(3) When ignition occurred, its delay is increased with the intensity of thermal radiation and it seems that there is an exponential relation between these quantities.
(4) This ignition delay, moreover, is decreased with the density of wood and its result is similar to (2).
(5) In general, the total radiation energy required for ignition tends to take larger value in the low or high intensity region and has a non-constant value. This suggests that the wood is not always ignited when a constant critical energy is obtained.
Since size effect was neglected in this study, the results may not be applied to the fire protection practically, but it would contribute to the understanding of ignition mechanism of wood.

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In this paper I tried to estimate the quantity of radiant heat transfer from flame to wall and the curve of flame temperature rise in a burning concrete house which had the definite wall space and burning condition as shown in Table 1.
The method used in this paper is based upon Yagi and Kunii’s theory concerning radiant heat transfer in an industrial furnace. Applying this theory to a burning concrete house, I obtained the quantity of a radiant heat transfer, which was the important factor in this problem.
Epitome of the Method
I assumed that the inside of the burning concrete house is completely covered with flame of fire, the wall surface of the concrete house are all absorbing planes for radiation with emissivity ε_c and the outside from open parts of the wall (or window plane) are black body at outdoor temperature t₀°C as Fig. 1. Then, quantities of radiant heat exchange (q_ij) between planes (B,C) and flame are expressed in Eq. (1)
q_ij=A_iφ_ij(E_i-E_j) …………(1)
where, A_i, φ_ij and E_i are area of surface i, over-all interchange factor and emission power of black body, respectively.
Next, I considered the income and outgo of quantity of heat in the burning concrete house.
These relations are as follows.
(a) on the calorific value by fire and heat loss,
Q_H =q_GC＋q′_GC＋q_GB＋Q_L
(b) at the wall surface
Q_W =q_GC＋q′_GC
where, Q_H is calorific value of combustion of fuel in the concrete house, q_GC and q_GB are quantities of radiant heat transfer from flame to plane B and C. Q_L is quantity of heat carried away with the combustion gas, q′_GC is heat quantity by convection between flame and wall.
(c) temperature distribution in the wall estimated by Schmidt’s graphical solution for nonsteady heat conduction.
Results
I calculated above relations (a) to (c) under observed results obtained in two fire tests. Curves obtained are given in Fig. 2 and 3. In these figures flame temperature rises calculated by this method agree with practical rises at the climax time of fire (about 30 min. after the ignition). In fire test (I), about 40% of the heat quantity created by the combustion (G_H), is transferred from flame to the wall by radiation and 5% by the convection.

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The wind velocity distribution along the axis of jets, ejected from circular or rectangular orifices, was investigated in order to apply the results to the study of characteristics of a flame issued from the window in case of fire in a concrete house, or to that of upward current from rectangular-shaped heat source.
As for the air velocity v at the point whose distance from the orifice along the axis of jet is x, the following non-dimensional equation is approximately held ;
v/v₀=ƒ(x/r₀)……………(1)
where v₀ is the initial outflow velocity of jets, r₀ is the radius of the orifice. When the shape of orifice is rectangular, r₀ is the modified radius of the circle, which has area equivalent to that of the rectangle ; that is, r₀ must be modified by multiplying a factor α² tabulated in Table 1. A functional form of f in eq. (1) must be sought for by experiments.
In case of circular orifice, two regions can be distinguished as regard to the axial velocity ;
x≦10r₀ : v=v₀(constant)
x≧10r₀ : v=10v₀r₀/x
In case of rectangular orifice, three regions can be distinguished ;
x≦8.85r₀/√n : v=v₀(constant)
8.85r₀/√n≦x≦11.3√n r₀ : v=(2.977/4√n)√(r₀/x)
x≧11.3√n r₀ : v=10v₀r₀/x
where n (>1) is the ratio of the length of adjacent sides of rectangles.
In the second region, the axil velocity is inversely proportional to the square root of distance from the orifice, this is the same distribution as that of the jet from the line source.
In both cases, the last region is that, where the axil velocity is inversely proportional to the distance from the orifice, and this velocity distribution appeared over all regions when the source is a point, as pointed out by V. Tollmien.
Above-mentioned characteristics concerning the jet from a rectangular orifice can be applied to the vertical temperature distribution along the axis of upward current from a rectangular heat source. In case of circular heat source, the temperature decrease with the height is slight until the height corresponding to about three times of its radius, and in the higher region the temperature distribution responds to the law of Δθ∝z^-5/₃,
as is already reported by the same author.
In case of rectangular heat source, in the region higher than the height corresponding to about 3/2 times of length of shorter side of the rectangle, the temperature distribution is Δθ∝Z^-1, that is equal to that of the upward current from a line heat source, and at last at some height higher than that, the temperature distribution is transformed to Δθ∝z^-5/₃, that is equal to that of the current from a point heat source.

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In this paper the burning speed of cotton and staple fibre surface was investigated experimentally by the method of rotation drum, varying the burning angle and water content.
Following results were obtained :
1. As sample burned upwards, the influence of angle on surface burning speed was small at angles from 0 to 30 degrees, but became very great at about 60 degrees.
As downwards, the surface burning speed was scarcely affected by the angle of sample.
2. The surface burning speed was decreased conversely in accordance with the increase of water content, and this effect was greater at larger angles of sample.

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1. Object
The author picked up 14 examples of conflagration after World War II, occurred in Japan, and arranged their observed data of weather condition to make clear the nature of strong wind blowing in such large fires (conflagrations).
2. Results
a) We found, through those data, that certain course of typhoon causes foehn phenomenon, and these have greatly influenced conflagration in Hokuriku and San-in regions in Japan.
b) The relative humidity at the time of occurrence of a conflagration is not so low. It is considered that the effective humidity, or the water content of constructing materials of a building, has close relation to the conflagration.

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