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10.5

Part 10.5 Light

Part 10.5 Light

(1) Natural light must be provided to all habitable rooms, in accordance with the requirements of (2) to (5).

(2) Natural light must be provided by—

  1. windows, excluding roof lights that—
    1. have an aggregate light transmitting area measured exclusive of framing members, glazing bars or other obstructions of not less than 10% of the floor area of the room; and
    2. are open to the sky or face a court or other space open to the sky or an open verandah, carport or the like; or
  2. roof lights that—
    1. have an aggregate light transmitting area measured exclusive of framing members, glazing bars or other obstructions of not less than 3% of the floor area of the room; and
    2. are open to the sky; or
  3. a proportional combination of windows and roof lights required by (a) and (b).

(3) A window required to provide natural light that faces a boundary of an adjoining allotment must not be less than a horizontal distance of 900 mm from that boundary.

(4) Natural light to a room may come through one or more glazed panels or openings from an adjoining room (including an enclosed verandah) if—

  1. the glazed panels or openings have an aggregate light transmitting area of not less than 10% of the floor area of the room to which it provides light; and
  2. the adjoining room has—
    1. windows, excluding roof lights that—
      1. have an aggregate light transmitting area of not less than 10% of the combined floor area of both rooms; and
      2. are open to the sky or face a court or other space open to the sky or an open verandah, carport or the like; or
    2. roof lights that—
      1. have an aggregate light transmitting area of not less than 3% of the combined floor area of both rooms; and
      2. are open to the sky; or
    3. a proportional combination of windows and roof lights required by (i) and (ii).

(5) The areas specified in (4)(a) and (b) may be reduced as appropriate if direct natural light is provided from another source.

Notes

Figure 10.5.1 illustrates requirements of this provision.

Figure 10.5.1 Method of determining areas of openings for borrowed light
image-10-5-1-method-of-determining-areas-of-openings-for-borrowed-light.svg

Explanatory information: Explanatory Figure 10.5.1

A roof light generally receives greater exposure to sunlight than a window because of its orientation to the sky and consequently, the size of a roof light as a percentage of the floor area served is permitted to be smaller than for a window serving the same floor area. This is explained in Explanatory Figure 10.5.1, below.

Figure 10.5.1 (explanatory) Method for determining proportional combination of windows and roof lights
image-10-5-1-explanatory-method-for-determining-proportional-combination-of-windows-and-roof-lights.svg
Figure Notes
  1. Area of the room which requires natural light is 100 m2.
  2. No natural light is borrowed from adjoining rooms.

Explanatory information: General requirements for Explanatory Figure 10.5.1

Requiredwindow(s) to provide natural light must have a light transmitting area of at least 10% of the floor area.

10% of 100 m2 = 10 m2

Or, roof light(s) to provide natural light must have a light transmitting area of at least 3% of the floor area.

3% of 100 m2 = 3 m2 

In the formula shown in the next Explanatory Information box, 3% of the floor area is expressed as the fraction 0.03 and 10% of the floor area is expressed as the fraction 0.1.

Explanatory information: Calculations for Explanatory Figure 10.5.1

Formula — for the area of window(s) required to compensate for roof light(s) short fall:

Area of window(s) required to compensate for roof light(s) short fall:

If the roof light(s) = 1 m²

Formula — for the area of roof light(s) required to compensate for window(s) short fall:

Area of roof light(s) required to compensate for window(s) short fall:

If the window(s) = 5 m².

Notes:

  1. For the purposes of this example a window excludes a roof light.
  2. The same proportional calculation principle applies if—
    1. two or more windows are used; or
    2. two or more roof lights are used.

Explanatory information: Natural light borrowed from another source

  • Direct natural light provided from another source is intended to mean light from a window or roof light in the subject room. As the provision relates to natural light obtained from an adjoining room, ‘another source’ refers to direct natural light provided to the subject room which does not meet the required allowance of either 10% or 3% of the floor area of that room. By not meeting the required amount of natural light, the ‘direct natural light from another source’ can be used as a supplement to the natural light required from an adjoining room.
  • To borrow natural light from another room, 10.5.1(4)(a) allows light to pass through a glazed panel(s) or opening(s) from an adjoining room, which under 10.5.1(4)(b), must have windows, roof lights or a combination of windows and roof lights of a minimum size in proportion to the combined floor areas of both rooms. The minimum size of the glazed panel(s) or opening(s), and the minimum size of the window to the adjoining room are illustrated in Figure 10.5.1.
  • If a doorway is used as an opening to obtain natural light, it must do so when in the closed position (see Figure 10.5.1).

Sanitary compartments, bathrooms, shower rooms, airlocks and laundries must be provided with artificial lighting if natural light in accordance with the relevant provisions of 10.5.1 is not available—

  1. at a rate of not less than one light fitting per 16 m2 of floor area; or
  2. in accordance with AS/NZS 1680.0.