G4/AS1: Ventilation

G4 VENTILATION ACCEPTABLE SOLUTION G4/AS1 Spaces within buildings 2.2.1.3 Openable building elements shall be constructed in a way that allows them to remain fixed in the open position as a means of ventilation during normal occupancy of the building. 2.2.1.4 Natural ventilation of car parks shall comply with the natural ventilation part of AS 1668.2 Section 7. 2.2.1.5 Spaces in household units and accommodation units that contain cooktops, showers and baths must have mechanical extract fans installed to remove moisture generated by these fixtures. Mechanical extract fans (including associated ducting) must have a flowrate not less than: a) 25 L/s for showers and baths; and b) 50 L/s for cooktops. COMMENT: Mechanical extract fans are intended to remove moisture from localised sources, and will not necessarily provide adequate ventilation for the whole occupied space. Within this acceptable solution, natural ventilation on its own is not adequate to remove moisture generated from cooktops, showers and baths. 2.2.2 Natural ventilation of household units and accommodation units with one external wall 2.2.2.1 Natural ventilation to both household units and accommodation units with only one external wall (such as those often found in apartments, hotels, and motels) must comply with Paragraphs 2.2.2.2, 2.2.2.3, 2.2.2.4, and 2.2.2.5. 2.2.2.2 Kitchens, bathrooms, toilets, laundries and habitable spaces with an external wall must be ventilated to the outside by: a) windows and/or other openings to the outside with a net openable area of no less than 5% of the floor area of the space; or b) high level trickle ventilators located through the external wall or in building elements within the external wall (see Paragraph 2.2.2.5 for trickle ventilators); and c) having a distance between the external wall and opposing wall of the space of less than 6 metres. 2.2.2.3 Spaces in household units and accommodation units that contain cooktops, showers and baths must have mechanical extract fans installed to remove moisture generated by these fixtures. Mechanical extract fans (including associated ducting) must have a flow rate not less than: a) 25 L/s for showers and baths; and b) 50 L/s for cooktops. COMMENT: Mechanical extract fans are intended to remove moisture from localised sources, and will not necessarily provide adequate ventilation for the whole occupied space. Within this acceptable solution, natural ventilation on its own is not adequate to remove moisture generated from cooktops, showers and baths. 2.2.2.4 Habitable spaces without openings to the exterior must be ventilated via another habitable space by: MINISTRY OF BUSINESS, INNOVATION AND EMPLOYMENT 28 JULY 2025 Page 9