Natural or mechanical air exchange in the hoistway that controls heat accumulation and removes combustion gases.
Full Definition
Elevator shaft ventilation is the provision of air exchange within the hoistway to prevent excessive heat build-up from the traction motor, drive electronics, and ambient heat transfer through the shaft walls, and to allow the escape of smoke and hot gases in the event of a fire. EN 81-20 clause 5.2.2 requires that the shaft have effective ventilation to the outside of the building; for non-fire-rated shafts, natural ventilation through openings at the top (at least 1 % of the shaft cross-sectional area) is typically sufficient. Where the shaft is used as a smoke control zone, the ventilation design follows EN 12101-2 (natural smoke and heat exhaust ventilators) or EN 12101-3 (powered smoke and heat exhaust ventilators). Mechanical shaft ventilation fans must be rated for operation at elevated temperature (300 °C for 60 min or 400 °C for 120 min depending on the fire resistance class) and sized to achieve the required air change rate under fire conditions while maintaining the designed pressure differential if shaft pressurization is also installed. In temperate and tropical climates, shaft ventilation is also engineered to manage the stack effect — the thermally induced pressure imbalance that can cause draughts through landing doors at lower floors and increase door-operating force. Ventilation openings must be protected by wire mesh or louvres to prevent vermin ingress while maintaining free airflow.
