Horizontal ventilation involves creating openings in exterior walls or windows to release smoke and heat when roof access is unsafe or not feasible. Which option describes this action?

• A. Creating openings in exterior walls or windows to release smoke and heat when roof access is unsafe or not feasible
• B. Sealing interior doors to confine smoke
• C. Venting through the roof only
• D. Using fans inside to push air out

Answer: (A)

Horizontal ventilation means venting smoke and heat to the outside through openings on the building’s exterior, rather than pushing it out through the roof. This approach is used when roof access is too dangerous or not feasible, so firefighters create openings in exterior walls or windows to let the hot gases escape directly from the fire floor. By opening these exterior points, the thermal layer is reduced and smoke conditions improve, which helps interior teams see better, move more safely, and buy time for occupants. Sealing interior doors to confine smoke doesn’t vent it at all; venting through the roof is a vertical form of ventilation, not horizontal; and simply using fans inside to push air out doesn’t establish the necessary exterior openings for proper horizontal ventilation.