A Study on Flame Spread Rate over Conveyor and Cable in Confined Space

为了弄清受限空间中的火灾行为，在模型风道中使用了纸张，在全尺寸的试验室中使用PMRA纸进行了实验。结果表明：1)尺寸条件(宽度和厚度)对受限空间中的火灾传播率的影响比在自由空间中更大；2)可燃材料接近管道顶端时，火灾传播率增加，但当间隙小于一定值后，火灾传播率开始下降。它在可燃性试验和实际对抗中都具有重要意义。3)通风极大地提高了与瓦片同向流动时的火势蔓延速度。当气流速度超过4m/s时，火焰被吹灭。当气流逆火运动时，蔓延速度随着风速的增加而减小，当速度超过1m/s时，火被扑灭。4)由于火灾产生的空气的浮力作用，火的蔓延速度随着管道的倾斜而增加。5)材料下表面的温度总是高于上表面的温度，相差可达数百摄氏度。

In order to clarify tlie behavior of fire in confined space experiments were performed with]i)ng sheets of paper in a model duct and with PMRA sheets in a full scale test gallery.Tie results obtained are summarized as follows ;1)The dimensional conditions(width and thickness)influences tlie fire spread rate more strongly in confined space than in free space.2)The fire spread rate increases as tlie combustible material nears the ceiling of duct, t)ut it begins to decrease after the clearance becomes smaller than a certain value. lliis is important both in combustibility test and in practical countermeasure. s to fire.3)Ventilation greatly enhances the spread rate when the air flow in the same direction as tile spread fire. However, the flame is blown out when the the air velocity exceeds 4 m. /s. When tile air flows against tlie movement of fire, the spread rate decreases with the air velocity and tile fire is extinguished with the velocity more than 1 m/s.4)The fire spread rate increases with the inclination of the duct because of tlie buoyancy effect of air created by the fire.5)The temperature of tlie lower surface of the material is always higher tl-ian tliat of tlie upper- one and tlie difference reaches some hundreds degree centigrades.