Fire Science and Technology
Online ISSN : 1882-0492
Print ISSN : 0285-9521
ISSN-L : 0285-9521
Volume 25 , Issue 1
Showing 1-3 articles out of 3 articles from the selected issue
Original Articles
  • Taku Shimada, Hideo Naoi
    2006 Volume 25 Issue 1 Pages 1-14
    Published: 2006
    Released: June 29, 2007
    JOURNALS FREE ACCESS
    Until now, the evacuation of wheelchair users from buildings in an emergency condition, cf. a fire, has not been considered enough. In this study, we made five experiments to grasp the characteristics of crowd evacuation flow including wheelchair users. Then we intended to grasp the relative decreasing trend of a flow coefficient to the able-bodied people group. Through these experiments, we recognized as follows: 1. In the range that crowd density is 2-8 [people/m²] the flow coefficient increases as the density increases. 2. The flow coefficient decreases as the wheelchair users mixing rate in the crowd increases, but inclination of decrease becomes gradual. 3. The width of door has little effect on the flow coefficient. 4. The flow of a self-moving type wheelchair is smoother than the assisted moving type. As a result of this study, we proposed a calculating formula using ergonomics factors, personal occupation area, crowd speed and the wheelchair users mixing rate, which shows nearly the same downward tendency as our experiments indicated.
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  • Yasushi Oka, Hitoshi Kurioka
    2006 Volume 25 Issue 1 Pages 15-29
    Published: 2006
    Released: June 29, 2007
    JOURNALS FREE ACCESS
    Experiments were performed to investigate the effects of the shape and size of a fire source on fire properties using a tunnel model with a rectangular cross section and aspect ratio of 1:2. Square and rectangular burners were used as the model fire sources. The variations in the heat release rate (HRR) from 4.5 to 36 kW was proportional to the fire size, and the longitudinal ventilation velocity was also varied in the range from 0 to 0.8 m/s. The flame tilt angle, maximum temperature rise of the smoke layer near the ceiling and its position were adopted as the variables that characterise the fire phenomena in the near field of a fire source in the presence of longitudinal ventilation. New empirical formulae considering the effects of the shape and size of a fire source on these variables were developed.
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  • Akiko Natori, Norichika Kakae, Jun Kitahori, Tsuneto Tsuchihashi, Tosh ...
    2006 Volume 25 Issue 1 Pages 31-54
    Published: 2006
    Released: June 29, 2007
    JOURNALS FREE ACCESS
    In performance-based fire safety design of buildings, design fires are assumed based on relatively coarse information of potential combustible objects described by the object name, weight, size and constituent materials. The fire effect is calculated by using assumed design heat release rate (HRR) to judge appropriateness of fire safety provisions. For this purpose, a simple estimation method to estimate design HRR curve (full time history of HRR) was developed. The method is based on summary of available experimental datasets of various combustibles, which were categorized into groups by their names and constituent materials. As a nature of categorized groups, there are two types of variations of HRR characteristics within each category group. One type is that the object size is almost constant within each category group. For this type, HRR curves are simply averaged over the available datasets in order to obtain the characteristic design HRR curve. The method was applied to chairs and sofas. The other type is that the object size varies within each category group. To develop size-dependent HRR curves, rates of fire growth and decay were averaged over datasets in the group. Maximum HRR and total heat release (THR) were correlated with surface area and weight, respectively. The method was applied to Christmas trees. By using the proposed methods, it is possible to establish a simple formula to represent full HRR diagrams by their category names.
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