A major fire can have a devastating affect on both property and people.  Although active fire protection such as sprinklers put out a fire, the smoke from the fire remains. This smoke can be harmful when not properly mitigated. Ventilation systems offer an effective method for the control of smoke.

Smoke can behave very differently in tall buildings than in low buildings. The predominant factors that cause smoke movement in tall buildings are stack effects, the effect of external wind forces, and forced air movement within the building. Smoke removal and venting practices are complicated by stack effects, which will tend to favour natural air movement vertically through the building as a result of differences in temperature and densities between the inside and outside air. 

Pressurization and smoke exhaust systems are methods of controlling the smoke in the event of a fire.  Life safety systems such as these are required to be fire rated so that service they provide will be continued in the event of a fire.