Building Code requirements
Passive ventilation must meet the requirements of Building Code clause G4 Ventilation. This includes ensuring that spaces within buildings have adequate ventilation for their intended use and occupancy, having adequate fresh air, and have means to remove moisture, products of combustion and other airborne contaminants.
Acceptable Solution G4/AS1 provides means of demonstrating compliance, including – for most buildings – that in occupied spaces the net openable area of windows and other openings must be at least 5% of the floor area. G4/AS1 also provides means of compliance for removing moisture and contaminants from kitchens, bathrooms and laundries, and for using active ventilation.