How does wind direction influence vertical ventilation?

• A. It has no effect on exhaust opening.
• B. It determines the color of smoke.
• C. It determines where and how large to make the exhaust opening to promote proper airflow and avoid blowing fire back into the structure.
• D. It only affects interior teams.

Answer: (C)

Wind direction shapes the pressure and air movement around the ventilation opening, which in turn determines how effectively hot gases exit and how much air is drawn in to feed the flow. The goal is to create a strong outward draft of heat and smoke while preventing wind from pushing those products back into the structure. So, you choose the exhaust opening’s location and adjust its size based on the wind: place the opening so the wind doesn’t directly oppose the draft, typically on the leeward side or high up to maximize outward flow, and size it to balance buoyant lift with wind pressure. If the opening is too large in a strong wind, wind can drive smoke back into the structure; if it’s too small, the flow won’t be sufficient to pull heat and smoke out. This is how wind direction influences vertical ventilation to promote proper airflow and avoid blowing fire back into the structure.