換気支配火災における未燃焼ガス流出に関する実験 Experiment on Out-flowing Unburned Combustible Gus on Ventilation Control Fire
This paper presents the characteristics of the compartment fire, especially the concentration of unburned decomposed gas, flowing out from a fire room at the ventilation control fire phase, which were investigated by the experimental study using a scale model. The experiment was conducted using an about 1/4 scale model of 600 width, 600 height and 1,200 depth constructed by 10 mm gypsum boards. The enclosure was set only one opening which is either vertically narrow or horizontally narrow with various sizes. PMMA plates or methanol in pan were burned at the center of the compartment. The concentration of hydrocarbon as an indicator of unburned gas and other terms such as ventilation rate, consumption rate of burning source and temperature field were measured. <br>The experimental results are summerized as follows. (1) As compared with liquid fuel, solid fuel like PMMA burned more slowly, of which consumption rate was proportioned to the square of time as the former being nearly constant. But in a compartment fire the relationship of burning rate with temperature, flow rate and gas concentration was not substantially different between both fuels except for their own material characteristics. (2) The consumption rate on the fuel control fire was nearly proportional to the opening factor and the rate on the ventilation control fire was larger than the value at free space burning condition for reasons of heat reception of fuel in room. (3) Though the unburned decomposed gas is essentially generated at the ventilation control fire, we can point out that the concentration was not monotonously inverse proportion to the opening factor and the maximum point of gas concentration was found in the ventilation control range near the border with fuel control range. (4) In case of vertically narrow opening such as 300 width and 100 height, fire characteristics were considerably changed with the disparity of the vertical position of the opening. The experimental evidences showed that it resulted from the change of in-flowing route of fresh air. In case of the opening touched with the floor, the out-flowing unburned gas became dangerously high concentration.
日本火災学会論文集 43(1), 1-9, 1995-09-30