Which statement best describes horizontal ventilation and when it should be performed?

• A. Exhausting air with interior fans without opening exterior.
• B. Opening a roof opening to vent heat and smoke upward.
• C. Venting through exterior openings on the same floor to release heat and smoke; performed when conditions allow for safe interior operation and to improve visibility and air supply.
• D. Ventilating by closing doors to confine the fire.

Answer: (C)

Horizontal ventilation means venting heat and smoke through exterior openings on the same level as the fire to create a flow of air that clears the space and improves conditions inside. It’s done only when conditions allow safe interior operation and when opening exterior openings will help, not hinder, the firefighters working inside. The goal is to establish a favorable flow path: fresh air enters through an exterior opening and hot gases and smoke exit through another on the same floor, lowering heat and increasing visibility for interior crews. This tactic should be coordinated with the fire attack and implemented when it’s safe, after the location of the fire has been identified and crews have a plan and exit routes. Roof venting is a vertical method and serves a different purpose, while simply closing doors to confine the fire isn’t ventilation at all; using interior fans without exterior exhaust won’t effectively remove heat or smoke.