What is positive-pressure ventilation?

What is positive-pressure ventilation?

• A. The use of a fan to blow clean air into a structure and force fire gases out.
• B. Ventilation achieved by opening doors and windows without fans.
• C. Ventilation using natural draft through openings only.
• D. Circulating air within a space without exchanging with outside air.

Answer: (A)

Positive-pressure ventilation is a mechanical method where a blower pushes clean outside air into a structure. By increasing the pressure inside, it creates a flow that drives smoke, heat, and gases out through exhaust openings, making conditions safer for occupants and firefighters and improving visibility for rescue efforts. This approach is active and controlled, unlike simply opening doors and windows without a fan, which relies on natural flow; it’s different from natural draft, which depends on wind and is unpredictable; and it doesn’t just recirculate interior air without bringing in fresh outside air.