This standard provides design guidelines for natural ventilation in public buildings. It outlines methodologies for calculating airflow based on wind action and stack effect, and provides recommended air change rates for various types of public occupancies to maintain indoor air quality and comfort.
Provides recommendations for achieving adequate natural ventilation in various types of public buildings.
Quick Reference Values
Coefficient (K) for wind perpendicular to opening0.6
Coefficient (K) for wind at 45 degrees to opening0.3
Recommended ACH for assembly rooms/auditoriums4 to 6
Recommended ACH for hospital wards6 to 8
Recommended ACH for offices3 to 6
Recommended ACH for libraries3 to 5
Key Formulas
Q = K * A * V — Rate of air flow due to wind action
Q = 7.0 * A * sqrt(h * dt) — Rate of air flow due to stack effect (temperature difference)
Practical Notes
Always align building orientation with the prevailing summer wind direction to maximize cross-ventilation.
For effective cross-ventilation, inlet and outlet openings should be provided on opposite or adjacent walls rather than a single wall.
When relying on stack effect, maximize the vertical distance between the inlet (lower) and outlet (higher) openings to increase airflow.