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Volume 1 (1951 - 1952･･･
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Volume 1, Issue 1
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Paper
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Shizuo YOKOI1951 Volume 1 Issue 1 Pages 1-3
Published: 1951
Released on J-STAGE: June 08, 2015
JOURNAL FREE ACCESSIn a given city, the number of fires each day depends on the humidity, but when the humidity is fixed, the number of fires follows the Poisson’s distribution. In view of this, the critical meteorological conditions when the probability of the number of fires going over a given value, exceeds 0.01, can be calculated.
I define as the extent of danger of the outbreak of fires in each city, the mean value of annual number of outbreak of fires, divided by the number of population of that city.
According to my investigation on the cities in Japan, this number has some correlation to the annual mean value of temperature and population but it has little correlation with the annual mean value of humidity.
Since the value of multiple coefficient of correlation is 0.50, there must exist some complicated factors which affect the number of fires in each city, and which must be studied in the future.View full abstractDownload PDF (278K) -
Haruhisa MARUYAMA1951 Volume 1 Issue 1 Pages 4-5
Published: 1951
Released on J-STAGE: June 08, 2015
JOURNAL FREE ACCESSIt has been known that the occurrence of a fire is related to meteorological conditions and frequency of using fire, however these are not shown in detail at present.
It is described in this paper to what distribution law a fire follows, and by what factors of a fire the seasonal variation is ruled.
According to the survey concerning a number of daily fires in Tokyo during 1948-1949, pol’ya-Eggen-berger’s law is more followed than Poisson’s law by X2-test, but it can be said that a fire is caused based on Poisson’s law when factors of a fire are fixed.
It is proved, therefore, that θ, square root of a number of daily fires y, follows approximately normal distribution which population mean θ’ and the variance is 1/4. Then, we assume the following formula,
θ’=(β0+β1X1+β2X2+…) z·w
where,
Xi : meteorological elements
βi : const.
w : frequency of using fire
z : population in Tokyo.View full abstractDownload PDF (186K) -
Kaoru KITA1951 Volume 1 Issue 1 Pages 6-8
Published: 1951
Released on J-STAGE: June 08, 2015
JOURNAL FREE ACCESSPrinciple of pneumatic expansion fire detector shown in Fig 1 is represented by electrical equivalent R-C net work as Fig 2. So that the theoretical characteristics of this detector are obtained by applying the transient theory of this electrical network.
Next formula is a theoretical formula of pressure difference between chambers A and B when the detector was pushed into the constant temperature air.
In this case the displacement of the contact are proportional to the pressure difference.
P=hΘM{(1/(M-τa))(ε-t/M-ε-t/τa)-(1/(M-τb))(ε-t/M-ε-t/τa)}
M=(VAVB / (VB-VA)) R
P : pressure difference between chamber A & B
k : coefficient
Θ : temperature rise of air
VA : volume of chamber A.
VB : volume of chamber B.
t : time
R : leakage resistance
τa : thermal time constant of chamber A.
τb : thermal time constant of chamber B.
As this formula is a theoretical formula, the variations of characteristics by constructions or external forms are not represented satisfactorily, but it can be used for designing or manufacturing this detector as fundamental formula.View full abstractDownload PDF (209K) -
Matsujiro OYAMA, Jun MIYAMA, Kaoru KITA, Toshihisa USUBA1951 Volume 1 Issue 1 Pages 9-11
Published: 1951
Released on J-STAGE: June 08, 2015
JOURNAL FREE ACCESSDifference between normal rise of room temperature and abnormal one was measured under various circumstances.
The former means the rise due to domestic fire used for cooking or room heating, and the latter means those due to fire which will cause an accident.
The results indicated salient differences between them in many cases.
The purpose was to determine the rating concerning sensibility of fire detectors and installation of them.View full abstractDownload PDF (248K) -
Kenichi USUI1951 Volume 1 Issue 1 Pages 12-14
Published: 1951
Released on J-STAGE: June 08, 2015
JOURNAL FREE ACCESSWhen density of wooden houses is similar or when a large building which has several times of average building area exists in them, burning velocity, which represents the relation between the time from break out of fire and area burnt down, is calculated under several wind velocities and for several shape of the large wooden building.View full abstractDownload PDF (224K) -
Nobuichi SODA1951 Volume 1 Issue 1 Pages 15-17
Published: 1951
Released on J-STAGE: June 08, 2015
JOURNAL FREE ACCESSIt is not scarcely, that fire occurs from combustible substance such as wood shavings, paper wastes, hays and etc. Statistically, it is fact that wood working, paper working, weaving and spinning factories in which many rags are scattered over have many fires. Author design simple determination method and make comparison of burning degree of combustible substance to make clear what is combustible substance and express the burning degree quantitatively.View full abstractDownload PDF (217K) -
Kinichiro FUJITA1951 Volume 1 Issue 1 Pages 18-20
Published: 1951
Released on J-STAGE: June 08, 2015
JOURNAL FREE ACCESSIn the investigations of remained strength of many reinforced concrete buildings damaged by the war-fire for the purpose of judging their safety as it becomes necessary to clarify remained strength of the fire-damaged concrete, K. Kozaka, investigator of B. R. I., measured remainder ratio of chemically combined water in set-cement and then supposed the strength of the fire-damaged concrete from which the set-cement was taken out, referring curves. prepared by him, showing a relation between the maximum experienced temperature of fire-damaged concrete and the remained water ratio, and also a relation curve between the maximum experienced-temperature and remainder ratio of the concrete which was obtained by S. Takenouchi (investigator of B. R. I.)
However, it takes too much labours and time to apply the above supposing method to every position of structure that I devised another method, applying my theory of fire mentioned above. That is :
(a) At first, surveying dimensions of the room damaged by fire and average height and total breadth of openings, and supposing quantity of combustibles.
(b) Putting these values into the general formulas ((1)-(2) in the original paper written in Japanese), we can suppose theoretically the duration time and fire temperature g for the position subjected to average fire load, and then, this g is to be checked and ascertained by that gained from the Kozaka’s method.
(c) Using the values of and g thus obtained, we can compute the maximum experienced temperature at every depth of the fire damaged concrete members.
(d) From these computed temperatures, we can suppose the remained strength of every parts of the concrete, consequently the remained strength of each member and also that of whole structure.
(e) Though the above method takes less labours, it should be noted that this method cannot be applied to the parts especially severely heated.View full abstractDownload PDF (301K) -
Sadaiti NAKAMURA1951 Volume 1 Issue 1 Pages 21-23
Published: 1951
Released on J-STAGE: June 08, 2015
JOURNAL FREE ACCESS1. Using the solid-angle projection method the writer aims to find a theoretical method of the estimation.
2. Consider a point O on a surface parallel to a rectangular source S, shielded by a tree R, assuming its form to be a glove. The ratio of heat received AS-R (Fig. 4.) is
AS-R=AS-kAR (S. 1.)
where AS or AR is the ratio of heat received from the source S or R, and k is the trees′ shielding heat coefficient.
AS can be found easily by the use of the tables in Watanabe’s work etc. AR is
AR=sin2 γ sin θ (θ > γ)
where γ and θ are the angles shown in Fig. 1.
For the case γ > θ > -γ, AR is tabulated in Table 1.
3. When the source is shielded partially by a part of the glove, the procedure to obtain AS-R is exactly as before except that the term AR of Eq. (S. 1.) will correspond to a partial area of the ellipse on figures drawn by the solid angle projection method. For this case AR can be obtained by the subtraction and addition of area (Figs. 5･1, 5･2, 5･3), using Table 2.
4. If O has been shielded by more than one tree, one glove will often partially overlap the other on the projection. For this case in the evaluation of AR-S much time will be saved by measuring the area of the figures with a planimeter on projections.
But the writer has prepared a device to obtain approximate value of AR-S in special cases.
5. Examples of the estimation are to be seen in a work of the writer in Zôen Zassi, Tôkyô, Vol. 15, No. 2.View full abstractDownload PDF (262K) -
Takakage SAKURAI, Tomio IZUMI1951 Volume 1 Issue 1 Pages 24-26
Published: 1951
Released on J-STAGE: June 08, 2015
JOURNAL FREE ACCESSEvaluating the fire-proofness of the foam-forming fire-retardant paint, we have developed the test of “foam-forming faculty”, as secondary means. This faculty was measured by the volume of the foam per unit weight of paint, consisted of carbonized substances, produced when the paint was under heat. This method applied to the thio-urea-melamine resin-anilin-phosphoric acid-monoammonium phosphate system. The fire-proofness of this system was determined by JIS method.
The fire-proofness was not entirely predicted by “the foam-forming faculty”, as the former partially depended upon the specific properties of foam-forming materials. If the specific properties considered, “the test of foam-forming faculty” was effective in determining the fire-proofness of the paints as a secondary means.View full abstractDownload PDF (268K) -
Iwao OKI, Ichiro KUMAGAI1951 Volume 1 Issue 1 Pages 27-29
Published: 1951
Released on J-STAGE: June 08, 2015
JOURNAL FREE ACCESSIn order to ascertain discharging capacities for fire extinguishing purpose of the municipal water supplying nets, the Fire and Marine Insurance Racing Association of Japan with assistance and co-operation of the Waterworks Department of Tokyo Municipality and Tokyo Fire Defence Board, experiments took place on 24th October, 1950 at one section of Koumecho Sumida-Ku, Tokyo, the result which is as follows :
Experiments were made to ascertain natural hose discharging and pump discharging capacities and pressure at hydrants
(1) a single pipe line (2) net lines.
We have computed the distribution of flow and friction loss for each pipe line in accordance with Hardy-Cross method by using Williams-Hazen formula, and compared the values obtained with the results of the experiments.
We have found that in the case of the pipe net, the mean value of velocity coefficient C in Williams-Hazen formula is 44, that is, the discharging capacity is 44 percent of that for the case when C is assumed 100 as for ordinary cast iron pipe line.View full abstractDownload PDF (197K)
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