FLAME SPREAD OVER FUEL-SPILLED AND OR SNOW-COVERED ASPHALT ROAD/

Flame spread characteristics over the fuel-spilled and/or snow-covered asphalt road (both porous and non-porous) were studied experimentally from the point of view of fire hazard prevention in many fuel spill a ccidents on the urban asphalt road. A large scale pool burning occurs on the non-porous usual asphalt road, but flame spread and pool burnin g cannot occur on the porous asphalt road owing to the drainage of fue l. When the liquid fuel was spilled on the snow-covered road and ignit ion occurred, the liquid fuel burns on the fuel-soaked sleety snow lay er. On the thick snow layer, if the amount of spilled fuel was not so large, the combustion on the fuel-spilled region cannot continue for a long time, even for highly flammable fuels such as gasoline. However, if the snow layer was not so thick, and a large amount of fuel was sp illed, the sleety snow layer beneath the flame reaches the road surfac e with the lapse of time of combustion. The water layer due to snow-me lting is formed and pool burning occurs on the exposed road surface. O n the porous asphalt road, however, such pool burning cannot occur bec ause both the water and the fuel are drained. Comparison between the f lame spread rate measured on the fuel-spilled snow-covered non-porous road and that predicted by a simplified model suggested that both the mechanism of combustion on fuel-soaked sleety snow layer and the scale effect, causing a strong fire-induced convection flow should become i mportant factors for flame spread on the snow-covered road.