Natural Ventilation
Natural ventilation is the movement of sufficient volumes of fresh air through an apartment to create a comfortable indoor environment. Sustainable design practice incorporates natural ventilation by responding to the local climate and reduces the need for mechanical ventilation and air conditioning. To achieve adequate natural ventilation, apartment design must address the orientation of the building, the configuration of apartments and the external building envelope.
Natural cross ventilation is achieved by apartments having more than one aspect with direct exposure to the prevailing winds, or windows located in significantly different pressure regions, rather than relying on purely wind driven air. Apartment layout and building depth have a close relationship with the ability of an apartment to be naturally ventilated. Generally as the building gets deeper, effective airflow reduces.
Prevailing winds vary for different locations and depend on local conditions.
For coastal areas in NSW, cooling sea breezes in summer tend to come from a north-easterly direction
All habitable rooms are naturally ventilated.
Design Guidance
The building's orientation maximises capture and use of prevailing breezes for natural ventilation in habitable rooms.
Depths of habitable rooms support natural ventilation.
The area of unobstructed window openings should be equal to at least 5% of the floor area served.
Light wells are not the primary air source for habitable rooms.
Doors and openable windows maximise natural ventilation opportunities by using the following design solutions:
• adjustable windows with large effective openable areas
• a variety of window types that provide safety and flexibility such as awnings and louvres
• windows which the occupants can reconfigure to funnel breezes into the apartment such as vertical louvres, casement windows and externally opening doors.
The building's orientation maximises capture and use of prevailing breezes for natural ventilation in habitable rooms.
Depths of habitable rooms support natural ventilation.
The area of unobstructed window openings should be equal to at least 5% of the floor area served.
Light wells are not the primary air source for habitable rooms.
Doors and openable windows maximise natural ventilation opportunities by using the following design solutions:
• adjustable windows with large effective openable areas
• a variety of window types that provide safety and flexibility such as awnings and louvres
• windows which the occupants can reconfigure to funnel breezes into the apartment such as vertical louvres, casement windows and externally opening doors.
Operable balcony screens allow occupants to customise their environment and regulate access of natural light and ventilation
Design Guidance
Apartment depths are limited to maximise ventilation and airflow.
Natural ventilation to single aspect apartments is achieved with the following design solutions:
• primary windows are augmented with plenums and light wells (generally not suitable for cross ventilation)
• stack effect ventilation / solar chimneys or similar to naturally ventilate internal building areas or rooms such as bathrooms and laundries
• courtyards or building indentations have a width to depth ratio of 2:1 or 3:1 to ensure effective air circulation and avoid trapped smells
Effective cross ventilation is achieved when the inlet and outlet have approximately the same area, allowing air to be drawn through the apartment using opposite air pressures on each side of the building
Responding to the local climate reduces the need for mechanical ventilation and air conditioning
Natural cross ventilation is facilitated by limited apartment depths and use of dual aspect apartments
Natural ventilation is further enhanced by using generous window and door openings
Operable louvres allow residents to regulate natural ventilation
The floor plan above demonstrates one approach for how five of a total of eight apartments achieve natural cross ventilation
Design Criteria
1. At least 60% of apartments are naturally cross ventilated in the first nine storeys of the building. Apartments at ten storeys or greater are deemed to be cross ventilated only if any enclosure of the balconies at these levels allows adequate natural ventilation and cannot be fully enclosed.
2. Overall depth of a cross-over or cross-through apartment does not exceed 18m, measured glass line to glass line.
Design Guidance
The building should include dual aspect apartments, cross through apartments and corner apartments and limit apartment depths.
In cross-through apartments external window and door opening sizes/areas on one side of an apartment (inlet side) are approximately equal to the external window and door opening sizes/areas on the other side of the apartment (outlet side).
Apartments are designed to minimise the number of corners, doors and rooms that might obstruct airflow.
Apartment depths, combined with appropriate ceiling heights, maximise cross ventilation and airflow.
Part 4 Designing The Building
Amenity
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