Fire in a building creates a tremendous amount of heat and smoke. In many instances, firefighters must remove this heat and smoke before they can get close enough to extinguish the fire. When a hole is made in the roof, dark smoke and dangerous superheated gases are able to escape, because heat and smoke rise. Cutting a hole in the roof and breaking out windows in strategic locations allows the smoke to vent upwards, allowing cooler air to enter the structure from below. We call this “ventilation”. This also makes it much easier for the firefighters in the building to see. The reduced heat and improved visibility allow firefighters to safely and quickly rescue trapped occupants and extinguish the fire.

Other reasons for releasing the gases include being able to see how far the fire has progressed, and also reducing the possibility of flashover (an explosion due to thermal radiation feedback) or backdraft (an explosion of heated gases when air is introduced to a smoldering fire). One of the fastest avenues through which fires spread is the attic. Heat and smoke rise into the attic where fire can move quickly. Firefighters may go ahead of the fire on a roof, cut holes to access the attic and stop the fire from spreading. By venting the window of a room that’s on fire, it actually helps to contain the fire to the room of origin. Otherwise, heated gases spread throughout the inside of a structure. Ventilation really prevents more damage than it appears to cause!