巻号一覧
30 巻 (1980)
- 2 号 p. 51-
- 1 号 p. 1-
30 巻, 2 号
選択された号の論文の3件中1～3を表示しています
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論文
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田中 哮義1980 年 30 巻 2 号 p. 51-62
発行日: 1980年
公開日: 2012/11/26
ジャーナル フリーIn previous reports, we have introduced a theoretical model on fire in small scale buildings and then have treated the formulation, calculation method and experimental verification of the model. In this report, using computer simulation based on the theoretical model, we investigated physical characteristics and influences of building conditions on the initial stage of fire in small scale buildings. Some of the results found are as follows.
In the case of 2-floor house, flows throughout the building are strengthen compared with 1-floor house by the entrainment of hot gas rising in the stair case.
Influence of opening condition of building is also serious. Provided that the air for the combustion in fire room is sufficiently supplied, the narrower the breadth of the openings become, the weaker the flows throughout the house become and the less heat is brought out of fire room. As the result, the temperature and the heat transfer in fire room increase. Even when one of the two openings on 1st or 2nd floor of 2-floor building is closed, the flows throughout the building does not decrease largely and almost the same amount of air flows into the building to supply the entrained air in fire room and staircase. But as typically shown in the case when all windows on 2nd floor are closed, there are a few cases where the entrainment in staircases have little effect.
Thermal properties of walls also have effects on fire behavior. Concrete wall lowers fire room temperature because of its small insulation property as well as its incombustibility, and therefore is expected to benefit fire protection of houses.抄録全体を表示PDF形式でダウンロード (1336K) -
桜井 寛, 林 太郎, 柴田 優, 金原 清之, 井上 新郎1980 年 30 巻 2 号 p. 63-73
発行日: 1980年
公開日: 2012/11/26
ジャーナル フリーIn order to prevent the diffusion of smoke from a fire point at the beginning of a fire as well as to let people refuge easily toward safety zones, air shutters combined with the push and pull flow have been suggested and investigated as a means of prevention of fire.
In practical fire, if the air shutter is broken with the increase of the velocity of smoke, safety zones change into danger ones. However, if there are a lot of air shutters installed at the passageway along with the expansile direction of fire and smoke, it can be considered that they ensure sufficient time while people can refuge. So far, the flow characteristics concerning plural air shutters installed with a separated constant distance at the passageway have not been enough investigated.
From the above point of view, the important subject how plural air shutters are suitably installed for the prevention of fire is investigated. In this paper, internal pressure between air shutter ‘A’ and ‘B’ as well as the close correlation between the ratio of side flow velocity and the ratio of push-pull flow volume are discussed, according to the variation of air shutter sizes, side flow velocity and push-pull flow volume. Furthermore, the basic data of air shutters required for practical designs are derived from the results of experimental researches.
As a conclusion of this investigation, it is clearly found that plural air shutters installed at the passageway so as to let people refuge easily from the danger zone are very effective in excluding smoke at the beginning of a fire.抄録全体を表示PDF形式でダウンロード (731K) -
三門 恒雄, 秋田 一雄1980 年 30 巻 2 号 p. 75-80
発行日: 1980年
公開日: 2012/11/26
ジャーナル フリーIn the previous paper, the burning characteristics of grouped polymer cables were studied by using a new test method developed by authors. As the result, it was found that the flame spread rates for grouped PVC cables exhibit a peculiar retardation at a certain range of oxygen concentration in ambient gas flow, in contrast to a single cable (see Fig. 2).
The purpose of this study is to make clear experimentally the behavior and mechanism of this retardation. Main part of the experiment consists of the burning test for pre-heated poly-vinyl chloride cables. The effects of pre-heat temperature, flow rate of ambient gas, and cable numbers on the flame spread rate of the grouped cables were observed systematically.
Moreover, the concentration of hydrogen chloride in diffusion flame of the grouped cables fixed by a moving wire technique is analyzed, because the HCl released from PVC would act as a flame inhibitor.
The results are summarized as follows;
(1) Since the retardation of flame spread rate appeared in the burning of grouped PVC cables has never been found for PVC cables pre-heated at above 220°C and chloroprene rubber cables, this behavior is a special character of PVC cable, and perhaps relates to the dehydrochlorination in the first stage of the degradation of PVC.
(2) The relative concentration of gaseous hydrogen chloride in flame for the grouped PVC cables shows a maximum value at the same oxygen concentration where the above mentioned behavior appears. It is concluded, thus, that this retardation is concerned with the flame inhibiting effect of HCl.抄録全体を表示PDF形式でダウンロード (421K)
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