NCC window opening restrictions for bedrooms in SA

Where the NCC window opening restrictions come from

NCC 2022 Volume Two sets the Performance Requirement. H5P2(1) requires a barrier where people could fall “2 m or more from a floor through an openable window in a bedroom” or “4 m or more from a floor through an openable window not covered by (b)”. H5P2(2) requires the barrier to be, among other things, “capable of restricting the passage of children”.

Clause H5D3 provides that compliance with Part 11.3 of the ABCB Housing Provisions satisfies H5P2. Within Part 11.3, clause 11.3.1 assigns openable windows to clauses 11.3.7 and 11.3.8, and clause 11.3.3(2)(b) takes window barriers covered by those clauses out of the general balustrade rule. A Performance Solution is a different route to H5P2, assessed by the relevant authority assessing the building work.

The South Australian schedule to Volume Two Part H5 inserts SA H5O2, SA H5F2, SA H5P3 and SA H5D4 on space between buildings, and replaces H5D1(1) to refer to them; it does not vary H5P1, H5P2, H5D2 or H5D3. The South Australian variations listed on the ABCB’s Housing Provisions index, read on 27 October 2026, are to Parts 4.2, 9.2, 10.2 and 13.1. The ABCB records that NCC 2025 was published on 1 May 2026 and lists South Australia as “BCA: 1 May 2027 / PCA: 1 May 2026”; which edition applies to a particular application is for the relevant authority or building certifier to confirm.

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Which bedroom windows need protection: the 2 m and 1.7 m figures

Clause 11.3.7(1) provides: “A window opening in a bedroom must be provided with protection, where the floor below the window is 2 m or more above the surface beneath.” The clause is written in terms of the height of the floor above the surface beneath, not in terms of storeys; Figure 11.3.7 shows how it is applied.

Clause 11.3.7(2) applies where “the lowest level of the window opening covered by (1) is less than 1.7 m above the floor”. The explanatory information states: “If the openable part of the window is at least 1.7 m above the floor, no further protection is required.” It also states that where the floor level below an openable bedroom window is less than 2 m, clause 11.3.7 sets no specific requirements.

The explanatory information notes that “window” is not italicised in clause 11.3.7, so it is not limited to the NCC’s defined term, and captures openings “that may let in air but not light, e.g. metal louvres”.

What a window opening restriction device or screen must do

Clause 11.3.7(2)(a) requires the openable portion of the window to be protected with “a device capable of restricting the window opening” or “a screen with secure fittings”.

Clause 11.3.7(2)(b) requires that device or screen to “not permit a 125 mm sphere to pass through the window opening or screen”, to “resist an outward horizontal action of 250 N” against the window restrained by the device or the screen protecting the opening, and to “have a child resistant release mechanism if the screen or device is able to be removed, unlocked or overridden”.

Clause 11.3.7 does not express the limit as a gap in millimetres; its test is whether a 125 mm sphere can pass through the opening or the screen.

A restricted sash does not reduce the ventilating area counted under Part 10.6. The explanatory information to clause 10.6.2 states that the ventilating area of a window is measured as the size of the openable sash, “irrespective of the restrictions on the openable sash”.

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Child resistant release and the extra 865 mm barrier

Clause 11.3.7(3) provides that where a device or screen “is able to be removed, unlocked or overridden, a barrier with a height not less than 865 mm above the floor is required to an openable window in addition to window protection”. Clause 11.3.7(4) requires that barrier not to permit a 125 mm sphere to pass through it, and not to have “any horizontal or near horizontal elements between 150 mm and 760 mm above the floor that facilitate climbing”.

The explanatory information explains the reason for a release: a screen or restricting device “may be installed in a manner that allows it to be removed, unlocked or overridden in the event of a fire or other emergency to allow safe egress”, in which case the unlocking device must be child resistant. It states that “child resistance could be achieved by the need to use a tool, key or two hands”.

It also states that where a device or screen is securely fixed so that it cannot be unlocked or overridden, or is very difficult to remove without, for example, a drill, the 865 mm barrier “would not be required”. Where that barrier is required, a wall beneath an openable window, or fixed glazing under the openable part that meets the height requirements (the explanatory information gives “transom at least 865 mm above the floor” as an example), “can be considered as the barrier if the criteria in 11.3.7 are met”. It is the barrier in clause 11.3.7(3), not a substitute for the device or screen in clause 11.3.7(2).

Design options named in the explanatory information

The explanatory information to clause 11.3.7 lists three design solutions: a window designed so that no opening allows a 125 mm sphere through (it gives louvres as an example) and that resists a 250 N force; a window fitted with a fixed or dynamic device restricting the opening, which is “difficult for a young child to operate”; and an internal or external screen that does not allow a 125 mm sphere through and resists a horizontal outward force of 250 N.

It names “short chain winders and barrier screens” as hardware that will allow windows to comply, and states that “sliding window locks may lock a sash so a 125 mm sphere cannot pass through”. Where the window can be opened fully beyond that, it states that the child resistant release mechanism is required in addition to the 250 N resistance.

Windows in rooms other than bedrooms: the 4 m rule

Clause 11.3.8(1) requires protection to a window opening in a room other than a bedroom “where the floor below the window is 4 m or more above the surface beneath”. Clause 11.3.8(2) requires the openable part to be protected with a barrier not less than 865 mm above the floor, and clause 11.3.8(3) requires that barrier not to permit a 125 mm sphere to pass through it and not to have horizontal or near horizontal elements between 150 mm and 760 mm above the floor that facilitate climbing.

This is separate from a window that itself serves as a barrier, for example along a floor edge, which clause 11.3.4(10) sends to H1D8 and the other provisions of Part 11.3. Balustrades to stairs, balconies and decks are covered in a separate note.

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