The new SANS 10400-O: Lighting and Ventilation Ed4 (2025) introduces updated minimum standards for ventilation systems under South Africa’s National Building Regulations. The standard represents a paradigm shift from unattested air changes per hour (ACH) to evidence based additive methods for determining minimum fresh-air ventilation rates. This new approach accounts for factors such as ventilation effectiveness, airborne transmission risk, occupant load, and the room occupied volume, enhancing ventilation efficiency, effectiveness, and air quality in occupied zones while overcoming inefficiencies from previous methodologies.
For artificial ventilation, the standard now accounts for contaminant removal effectiveness and provides for recirculating treating and reusing room air, with differentiation between treated air and outdoor air. Room air cleaner performance is accommodated and standardised, requiring compliance with performance metrics like Clean Air Delivery Rate.
Natural ventilation criteria include performance criteria such as CO2 limits for occupied spaces, and the recognition of mixed-mode systems. The neutral pressure plane concept is introduced, clarifying rules for aperture placements for buoyancy driven ventilation. Additionally, the standard covers exhaust systems specifications for facilities handling HBAs. Commissioning protocols for natural ventilation systems are also detailed.
The new SANS 10400-O-ed4 provides minimum ventilation standards based on evidence based and locally appropriate ventilation effectiveness and transmission risk metrics. The standard adopts current global best practices and is adapted from standards and guides such as ASHRAE-162.1, WHO, and CIBSE-AM10, ensuring a robust framework for ventilation design in South Africa. These changes aim to harmonize energy efficiency while permitting modern dynamic indoor air quality management methods.