| In Canada and Québec, there is a residential fire every thirty minutes approximately, and those fires are responsible for more than eleven billion dollars in damages every year. Even if all fires should not be considered equal, they all represent a threat for life that cannot be underestimated. However, of all types of fires, there are some that represent a greater danger than others. Thereby, the ones that are most feared by fire departments are the fires which result in an explosion. Many sources of explosions are present in residential housing, like aerosol cans, or explosive chemicals, but there is one type of explosion that is less frequent but also more sneaky, the backdraft. This type of explosion happens when there is a sudden inrush of air in a burning building where combustion has been taking place in shortage of air which caused an accumulation of pyrolysis products. When fresh air enters the building, usually when firefighters force entry, the oxygen mixes with unburned pyrolysate and creates a flammable region. If an ignition source is present to ignite the flammable mixture, the expansion created will push the gases outside of the building where they will burn in a large fireball. (Abstract shortened by UMI.). |
