Impact of Wildfires on LPG Tanks

Abstract

Research on wildland fires focused traditionally on two main objectives: the prediction of the velocity at which a fire will spread and the estimation of the released heat from the flame front of the wildland fire. Both topics are key points in order to evaluate the gravity of the fire and to organize firemen intervention to fight the fire (Alexandridis et al., 2011). The wildland-urban interface (WUI) may be defined as a contact zone between a natural zone such as a forest and a heavy or light urbanized area. At this interface, the threat to homes and their destruction during wildland fires, with associated concerns for life safety, are significant problems for emergency managers throughout the world. Due to the increasing urbanization of the surrounding countryside, the number of these areas is growing rapidly. In the last ten years, wildfires resulting in residential destruction occurred in Australia, Canada, Mediterranean countries and the United States. The WUI areas are complex systems, difficult to manage, especially in the context of wildfire prevention. (Butler, 1974) contributed the first description of urban wildland interface not in geographic terms but in terms of fire process. He defined that interface as the occurrence of fire spreading from wildland fuel (vegetation) to urban fuel (homes), in terms of the wildland fire becoming close enough for its flames and (or) its firebrands (lofted burning embers) to contact flammable parts of a home or the home’s immediate surroundings. The main question of his description is “How close is close enough for home ignition ?”. Well know operational models of fire spreading (for example BEHAVE, FIRE CODE, FORE FIRE models) are no longer valid in the urban interface. Some authors coupled wildfire dynamics with structure ignition models. (Cohen, 2000) proposed the Structure Ignition Model (SIAM). This model is based on strong assumptions, as the flame is assumed to be a uniform parallel-plane black body emitter. The flame-tostructure distance does not allow for flame contact. This model overestimates the heat received by the structure, as reported by (Porterie et al., 2007). These latter authors developed a three-dimensional physics-based model able to describe the near-field dynamics of a wildland fire, as well as its impact on structural elements. This model was validated by a prescribed burning and fire tunnel experiments. (Zarate