How far may a window open when children live there?

One bedroom window, checked step by step

The window in this example belongs to a first-floor bedroom in an apartment in a NSW strata scheme: the floor its sill stands on is 2.6 m above the ground outside, and its sill sits 0.75 m above that floor. Every check below uses only the numbers the two laws themselves print.

1. Does either law apply at all?

   The code’s own words narrow its rule to a particular kind of window: “D3D29(2)(b)(iii) relates to a screen or window restricting device protecting an openable window in a bedroom of a Class 2 or 3 building or Class 4 part of a building or in a Class 9b early childhood centre,” and the drop of “2 m or more above the surface beneath” is the condition just before it. In NSW the question asks about the building first: a building in a strata scheme falls under the window safety law where it holds lots used for residential purposes. A window is caught when it meets five conditions, and the regulation writes them as a list: “(a) it is a window within the meaning of the Building Code of Australia, and (b) it can be opened, and (c) the lowest level of the window opening is less than 1.7 metres above the surface of any internal floor that abuts the wall of which it forms part, and (d) that internal floor is 2 metres or more above the ground surface, or any external surface, below the window that abuts the wall, and (e) it is a window on common property to which access can be gained from a residence in a strata scheme or a window on any part of the building that is part of a residence.” Our window is a first-floor bedroom window in a scheme of residential lots: both laws apply, and the rest of these steps check the three numbers they print.

2. The 2 m drop below the floor

   The code puts the floor, not the window, at the centre of the test. On the way out of the rule: “Where the floor level below an openable window is less than 2 m there are no specific requirements.” NSW’s condition (d) asks the same of the internal floor, and it is the sentence people quote when they wonder whether a ground-floor window matters. Our bedroom’s floor is 2.6 m above the ground, so this first test is passed: the window is the kind the rules are written for.

3. The 1.7 m sill above the floor

   A high sill is the second way out of the rules: “If the openable part of a window is at least 1.7 m above the floor, no further protection is required.” NSW measures the same way, in condition (c) above, from the lowest level of the window opening to the floor that abuts its wall. Our window’s sill is 0.75 m above the floor, well under the 1.7 m line, so this test does not excuse it. Both laws read this number the same way: it is about the lowest part of the opening, which is why a window that opens only at the top can still need a device when its sill is low.

4. The 125 mm sphere, and the 250 N push

   With the drop more than 2 m and the sill under 1.7 m, protection is required, and the code states its size. Its list of design solutions includes a window “fitted with a fixed or dynamic device that is capable of restricting the window opening so it does not allow a 125 mm sphere to pass through and is difficult for a young child to operate,” or an “internal or external screen that does not allow a 125 mm sphere to pass through and which must resist a horizontal outward force of 250 N,” with the restricting device resisting that same 250 N force. NSW writes the same requirements into its complying device, as a list of three: “(a) is capable of restricting the opening of a window so that a sphere having a diameter of 125 millimetres or more cannot pass through the window opening, and (b) is capable of resisting an outward horizontal action of 250 newtons, and (c) has a child resistant release mechanism, in the case of a device that can be removed, overridden or unlocked.” The 250 N figure is worth holding on to: 25 kg of push is not a child’s strength, and it is the same force in both laws.

5. Releasing it, and the barrier that follows

   Both laws allow the window to be opened fully again, and both attach a second device to that choice. The code’s sentence is direct: “The screen or opening 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,” and “In these situations the unlocking device must be child resistant.” Child resistance, in the code’s own words, “could be achieved through the use of a tool, key or two hands.” And where the window is to open fully past 125 mm, the code’s answer is that the release mechanism joins the 250 N requirement rather than replacing it: “D3D29(3) in addition prescribes that an 865 mm barrier (sill) would be required.” A wall beneath the openable window can serve as that barrier, in the code’s own words, “if the criteria in D3D29(4) are met.”

6. What NSW adds after the lock is in

   New South Wales keeps one duty the code does not: an owner who installs a device under section 118 must tell the owners corporation in writing within 7 days of finishing the work. The state’s page also gives the rule in plain words: “Certain windows must have a child safety lock to prevent accidents from falls”; “A safety lock must stop the window opening more than 12.5 cm”; “All locks must be childproof and resist force equal to 25 kgs”; and “Fixed windows (those that do not open at all) do not require a lock.” One further plain point from the same page: security screens such as bars or grills can be used instead, and where they are, “any gaps must be less than 12.5 cm.”

The two laws, number by number

What the numbers are for

The reason the rules read a window so carefully is the fall itself, and NSW Health’s Kids Don’t Fly material says why in three sentences: “An increasing number of children are admitted to hospital each year as a result of falling from windows and balconies.” “These falls are often in their own home and can result in death or serious injury.” “Children aged from one to five years are most at risk as they are naturally curious but lack the ability to recognise danger.” The season matters too: “Falls occur more often in the warmer months when families leave windows and doors to balconies open both during the day and at night.” And the booklet draws the line that answers the commonest mistake on the subject: “Children can fall out of a window which is open more than 12.5cm, even if a flyscreen is fitted.” A flyscreen is allowed instead of a lock, in the state page’s words, “only if they can resist very strong outward pressure to stop a child falling through.”

Older homes are the other half of the story. NSW Health’s 2012 booklet said there were no laws requiring window and balustrade openings in older buildings to meet current building standards; since then NSW has required window safety devices in residential strata buildings, which owners corporations had until 13 March 2018 to install. That is why the code’s requirements attach to new buildings and NSW’s window safety law reaches into strata buildings that contain lots used for residential purposes. If the device is being bought rather than paid for by an owners corporation, one piece of advice from NSW Health’s product guide is worth keeping: “Check that any window safety product you purchase has been subjected to load testing,” because, as the same guide explains, “there is no Australian Standard for Window Fall Prevention Devices,” so “Australian products are tested against a variety of international standards with a minimum load testing of 333N as required by the American Standard Specification for Window Fall Prevention Devices.”

For a household in a rented apartment, the same booklet has two sentences worth knowing before the landlord is asked: “If you live in a rented property make sure to get your landlord’s written consent before adding a fixture or making an alteration to your home,” and, “By law, a landlord cannot unreasonably refuse consent for a tenant to make minor changes, such as installing window safety devices or other security features.”

The official first aid and prevention guidance is NSW Health’s Kids Don’t Fly brochure and its window safety product guide, both linked in this page’s sources; the laws that followed in 2013 are reported by Product Safety Australia; this page states no first-aid steps of its own.