Ventilation (firefighting)

In firefighting, ventilation refers to the tactic of creating a draft with an opening above or opposite the entry point so that heat and smoke will be released, permitting the firefighters to find and attack the fire. If a large fire is not properly ventilated, not only will it be much harder to fight, but it could also build up enough poorly burned smoke to create a smoke explosion, or enough heat to create a flashover. Contrarily, poorly placed or timed ventilation may increase the fire's air supply, causing it to grow and spread rapidly.

Mechanical fans can be used for such ventilation tactics, as can existing openings such as windows, skylights or scuttles on the roof. If there is no suitable existing hole, firefighters may use their equipment to make one, such as specialised saws for cutting a large hole in the roof. A conical hose-stream aimed out through an opening may also be helpful, in a process called "hydraulic ventilation", creating a small positive pressure in the room.

Modern designs of high-rise buildings sometimes also incorporate automatic ventilation equipment to produce a positive pressure in smoke-proof stairwells and elevator shafts.

When glass windows in a burning structure burst from internal pressure and heat, or the fire burns through the roof, it may be said to have "auto-ventilated" or "self-ventilated."