Natural Ventilation for Fire Safety: When It Works and When It Doesn't

Natural smoke ventilation can be effective and cost-efficient, but only in the right conditions. We explain the design principles.. Natural Smoke Ventilation How It Works Natural ventilation relies on buoyancy — hot smoke rises and exits through openings at high level, drawing in fresh air at low level. When It Works Corridors with external walls (AOV at head of corridor) Stairway tops (1m² minimum AOV) Single aspect buildings with adequate vent areas Lobbied approaches to stairways When It Doesn't Work Internal corridors with no external wall access Complex geometries where wind effects are unpredictable Very tall buildings where stack effect dominates Basement spaces with no natural vent route CFD Validation For complex situations, CFD modelling should validate natural ventilation effectiveness before relying on it. For smoke ventilation design, contact us.