Part F3 Room heights
FP3.1 Room or space heights
A habitable room or space must have sufficient height that does not unduly interfere with its intended function.
The Objective of this Part is to safeguard occupants from injury or loss of amenity caused by inadequate height of a room or space.
Basis of Objective
FO3 is based on the belief that people should not be subject to risk of injury or loss of amenity caused by the inadequate height of a room or space.
Risk of injury
The height of certain rooms and spaces must be controlled to prevent injury to occupants.
Loss of amenity
The height of certain rooms and spaces must be controlled to prevent a loss of amenity to occupants.
A building is to be constructed to provide height in a room or space suitable for the intended use.
Height suitable for use of a room or space
Buildings must provide a height suitable for the intended use of rooms and spaces. ‘Intended use’ recognises that the height required in rooms and spaces is directly related to the room’s function.
The intent of FP3.1 is to ensure that the height of a room or space is sufficient for the intended use of the room or space. 'Intended use' recognises that the height required in a room or space is directly related to the room or space's intended function.
FP3.1 adds the term ‘sufficient’ when describing the required level of performance. The required height must be considered in light of intended function.
The Deemed-to-Satisfy Provisions specify different heights for different room or building types.
Measurement of height
To achieve the requisite level of performance, it is necessary, when measuring the height of a ceiling, to make the measurement:
- from the floor to the underside of the ceiling lining; or
- if there is no ceiling lining, to the underside of the floor or roof above.
Exposed beams are permitted to encroach below the minimum ceiling height, but care should be taken to make sure that adequate height is still available.
In the case of stairs and ramps, the measurement is taken vertically from the nosing line of the stairway treads or the floor surface of the ramp, landing or the like, with no overhead projection encroachments permitted.
FV3.1 Room or space heights
Compliance with FP3.1 is verified where the height of a habitable room or space provides an appropriate activity support level that does not unduly interfere with its intended function.
For the purposes of (a), the activity support level must consider the dimensions of—
fixed fittings and services; and
fixed and moveable equipment or furniture; and
occupant circulation spaces.
FV3.1 is a means to verify that the height of a habitable room or space is suitable for the intended use, and therefore meets the requirement of FP3.1.
In relation to the intended function of a room or space, the activities that are likely to be undertaken by occupants in the room or space, as well as the features of the activities, are relevant considerations when determining a suitable height.
For example, if the intended use of a room is a gymnasium, then gymnastic activities are likely to be undertaken in the room. These activities often involve jumps and flips which require significant space in order to be undertaken safely.
In terms of the occupants, their features and needs are also relevant when determining a suitable height. For example, occupant features and needs would differ between rooms or spaces intended as a child's play area, and rooms or spaces intended for adult's indoor cricket.
The method requires the consideration of occupant characteristics and activity characteristics through the defined terms 'activity traits', 'occupant traits' and 'activity support level'. Refer to Schedule 3 for more information on these terms.
When determining the activity support level, the method requires consideration of the relevant dimensions of items likely to be located in the room or space, as well as occupant circulation spaces.
Some of these considerations are explained below:
- Stairs and ramps, since the height of the room or the space will change relative to the occupant during incline and decline.
- Fixed fittings such as lights that may protrude from the ceiling and wash-basins.
- Fixed services such as air-conditioners, heaters, ceiling fans and heated water systems.
- Fixed equipment such as manufacturing or processing equipment, permanent signage or displays and lifts.
- Moveable equipment such as whitegoods.
- Fixed furniture such as built-in wardrobes and permanent seating.
- Moveable furniture such as wardrobes, desks and beds.
- Occupant circulation spaces so that occupants can move comfortably and safely around the room or space.
For example, the location and dimensions of a washbasin is a relevant consideration in determining the activity support level of a bathroom. This is because an occupant will typically need to access the washbasin whilst standing, which will influence the necessary height of the space.
Another example is the consideration of moveable equipment such as a refrigerator in a kitchen. If the intended use of the space is a kitchen, then it would be unrealistic to determine a sufficient height for the room without considering the height of a typical refrigerator that would be located in the room.