One of the keys to successfully extinguishing a fire inside a building is to ventilate. Ventilation is the process by which byproducts of the fire (heat, smoke, and gasses) are removed from the structure so an interior attack can be made. Only firefighters or those who have experienced a fire first-hand can appreciate the untenable conditions inside a burning building.
Despite simulated fires seen in the movies or on television, the reality is that firefighters enter smoke-filled structures virtually blind and highly vulnerable to high temperatures, which can soar past 1,000 degrees at the ceiling.
Even with all our protective gear on and our air packs, firefighters cannot survive long when exposed to such extreme temperatures. Therefore it is imperative that the worst of the smoke and heat be removed in order for firefighting operations to be done properly.