Flame Spread along a Thin Combustible Solid with Randomly Distributed Square Pores of Two Different Sizes

The objective of our study is to predict the flame spread route by the quantity of combustible materials and their placement. In this paper, we examine non-uniform flame spread in open air along a thin combustible solid with randomly distributed square pores of two different sizes (8 x 8 and 4 x 4 mm respectively). Experimental results show that the flame-spread probability falls with increasing porosity. Despite uniform porosity, the flame-spread probability differs with the rate of large square pores to small square pores. For a combustible area larger than a noncombustible area, the flame-spread probability reaches the local minimum value with a change in R8 (ratio of 8 mm pores) under the same porosity condition. Conversely, for a combustible area smaller than a noncombustible area, the flame-spread probability reaches a local peak with changing R8 under the same porosity condition. In addition, we calculated the ratio of the unburned area (unburned area / total combustible area) by counting the unburned cells after the flame spread test, which might be useful to predict the fire hazard. We found that the ratio of unburned area grows with increasing porosity.