Which statement about horizontal ventilation is true?

• A. It uses openings on the roof
• B. It involves creating openings on the same level to allow air flow and smoke removal
• C. It seals interior doors to prevent smoke movement
• D. It relies on exterior winds to pull smoke away

Answer: (B)

Horizontal ventilation moves smoke and heat out through openings on the same level to establish a lateral air flow. By opening a window or door on the floor where the fire is, hot gases escape horizontally, and fresh air is drawn in to push smoke toward those openings. This reduces heat buildup and improves visibility inside, making it safer for firefighters to operate. Opening the roof would be vertical ventilation, which uses the upward path of buoyant gases. Sealing interior doors or relying on wind to pull smoke away aren’t controlled ventilation methods and don’t create that deliberate on-the-same-floor air flow.