Fire as a piece of furniture fire grows, a thermal updraft column on each side is created forcing the new oxygen to enter the combustion from the low area of the fire. The thermal column travels to the ceiling and transfers to the outside of these two columns by turbulence and mushrooming of the gases begins the process of filling of the space that is not in a flow path outside of the the thermal column and the air intake to the combustion of the furniture. The over-pressure and turbulence at the top of the thermal column is the method the fire uses to acquire the remainder oxygen in the compartment until/or the fire acquires an additional flow path to bring fresh oxygen into the compartment such as an open door or failed window.
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This knowledge impacts such areas as enhanced streams, stream application skills, predicting hazardous fire events and many more.