G4/AS1: Ventilation

G4 VENTILATION ACCEPTABLE SOLUTION G4/AS1 Definitions Term Definition Household unit a) means a building or group of buildings, or part of a building or group of buildings, that is— i) used, or intended to be used, only or mainly for residential purposes; and ii) occupied, or intended to be occupied, exclusively as the home or residence of not more than 1 household; but b) does not include a hostel, boarding house, or other specialised accommodation. Intended use In relation to a building – a) includes any or all of the following: i) any reasonably foreseeable occasional use that is not incompatible with the intended use; ii) normal maintenance; ii) activities undertaken in response to fire or any other reasonably foreseeable emergency; but b) does not include any other maintenance and repairs or rebuilding. Natural draught The flow produced by the tendency of warmed gases to rise. Net openable area The area of windows or doors or other opening measured on the face dimensions of the openable building element concerned. Occupied space Any space within a building in which a person will be present from time to time during the intended use of the building. Other property Any land or buildings or part of any land or buildings, that are: a) not held under the same allotment; or b) not held under the same ownership; and c) includes a road. Outdoor air Air as typically comprising by volume: i) oxygen 20.94% ii) carbon dioxide 0.03% iii) nitrogen and other inert gases 79.03%. Permanent opening An opening which cannot be closed, this implies that doors, windows etc are NOT permanent openings, although door undercuts are. Room-sealed An appliance designed so that air for combustion neither enters from, nor appliance combustion products enter into, the room in which the appliance is located. Trickle ventilator A controllable ventilation opening through the external envelope to the outside to provide background ventilation. MINISTRY OF BUSINESS, INNOVATION AND EMPLOYMENT 28 JULY 2025 Page 17