Why are there Australian Standards for Balustrades?
Whilst balustrading can be decorative, the main purpose is to protect users from falls. Balustrades and other barriers are installed for the safety of users of stairways, ramps, floors, corridors, hallways, balconies, verandahs, mezzanines or other areas in buildings where there is the potential to fall from height.
So why are there Australian standards for balustrades? Balustrades that don’t meet Australian Standards can actually become a hazard themselves. Unsafe, absent or balustrading failure can lead to injury or death – a fall from even a seemingly small height can have catastrophic consequences if you land wrongly.
If you have been house hunting you may have seen a wide variety of balustrading on high-set homes. Some homes might be older with wooden balustrading that is in poor repair or that doesn’t meet current Australian Standards, allowing small children to fall through gaps or failure in the balustrading if an adult fell or leaned upon it. Other newer builds could have the more modern balustrading with glass installed that does not meet Australian Standards for glass balustrades.
Action Property Inspections always recommend a thorough building and pest inspection prior to purchase. However, on your first walk through a home, this basic overview may assist you to make an initial assessment about the likely safety of the balustrading of the property you are considering.
What are Australian Standards for balustrade placement?
The National Construction Code 2019 Building Code of Australia Vol 2 Part 184.108.40.206 specifies that for residential homes (and most other classes of buildings) any stairway, ramp, deck, verandah, balcony, landing or other trafficable surface that is more than 1000mm above the ground MUST have a continuous barrier of some kind, such as balustrading. There are limited circumstances where this does not apply.
As part of the Australian standards for handrails on stairways and ramps, there must be handrails provided where the trafficable area is creating a change in elevation of more than 1m in height. Continuous handrails must be located along the full length on at least one side of the flight or ramp (the handrail may form part of the barrier) and the top surface of the handrail must be not less than 865mm from the floor surface of the ramp or stair tread nosings.
As the intention of the barriers is to minimise the risk of falls, it is reasonable to expect that any area elevated 1m or more above the ground level, that is used regularly and provides general access to and from an area, will require balustrades or other barriers which are constructed in such a way as to minimise the risk of an adult falling over or through the barrier. It must also restrict children from crawling and falling through.
What are Australian Standards for height and gap in balustrades?
According to the NCC 2019 BCA Vol 2, Part 220.127.116.11 balustrades and barriers must be a minimum of 1m (1000mm) in height above the floor level of the path, balcony, landing or other structure where the opening to the ground is 1m or greater above the level of the ground surface (or more than 4m where a person could fall through an open window). The balustrade or barrier must be a minimum of 865mm in height above the floor level of stairways, ramps and short transitional landings (500mm or less). These minimum balustrade height requirements clearly reflect the need to reduce the risk of falling over the top of a barrier.
The Code specifies that any gaps in balustrading and barriers must be such that a sphere of 125mm cannot pass through the opening. Where the barrier forms part of a stairway, the 125mm distance is measured vertically from the nosing line of the stair tread to the bottom of the barrier. If you have ever observed small children playing near balustrading you will have an appreciation for how the Code’s gap allowance is intended to address the issue of small limbs fitting in tight spaces.
The diagram below, sourced from the NCC 2019 BCA, illustrates barrier requirements.
Do wire or rail balustrades comply with Australian Standards?
Have you come across wire balustrades on a deck? Or verandah balustrades made almost entirely of horizontal rails? If the floor of that deck or balcony is 3m from the ground below, it is quite possible that the balustrade might comply with the regulations. That same balustrade would not comply with regulations if the level of the floor of the deck was more than 4m above the surface below.
To comply with NCC 2019 Building Code of Australia specifications around barrier climbability, if the floor surface of the landing is more than 4m above the surface beneath, then any horizontal or near horizontal elements of the barrier between 150mm and 760mm above the floor level must not be climbable.
If the height of the deck or landing is 4m or more above the surface below, then the balustrading should be constructed of solid panels or appropriately spaced vertical members (for example, a horizontal bottom rail at 125mm, a middle rail at 760mm and top horizontal rail at 1000mm with 125mm spacing between each vertical).
In order to comply with requirements, wire balustrading does have other criteria it must meet (NCC 2019 BCA Vol 2, Part 18.104.22.168) including wire diameter, tension, spacing of wires (maximum of 100mm), posts spacing and more. Professionals installers have the specialist equipment required to measure things like wire tension.
What are Australian Standards for balustrade strength, including glass balustrades?
The NCC 2019 BCA covers the materials and methods and any Australian Standards that apply in the construction of balustrading, including the manner in which it is affixed to the trafficable area. Ultimately, the intent of the Australian regulations, codes and standards is to protect the safety of users. Whether the balustrade, railing or other barrier is constructed of wood, metal, wire, glass or another material, they must be capable of resisting the forces that would be expected to be placed on them such as people leaning against them, strong winds or the load of a person falling against them.
AS/NZS 1170.1 requires balustrades or barriers to be capable of withstanding a 0.6kN point load (eg a person falling onto the barrier) and the handrail to withstand a distributed load of 0.4kN applied inward, outward or downward (eg: leaning on the barrier).
All glass balustrades must comply with Australian Standard AS 1288: Glass in Buildings – Selection and Installation. Whilst all glass balustrading must be made from Grade A Safety Glass, the installation environment (ie height, load and forces it will be subject to etc) will affect the exact specifications such as size, thickness and method of installation allowable. Glass balustrading now requires an interlinking handrail to be installed on all structural glass balustrading where it is providing a barrier for a height of 1m or more.
As discussed above, horizontal wire balustrading is covered by the NCC 2019 BCA Vol 2, Part 22.214.171.124. Importantly, the many specifications are designed to ensure that the wire safe load limit is not exceeded, which could lead to catastrophic failure of the wire system.
Ultimately, even balustrading initially constructed in accordance with all the relevant codes and standards can become hazardous if it is not regularly inspected and maintained. Deteriorating wood, rusting fixings, wear at anchor points and insecure handrails are some of the signs of balustrading failure and pose a major safety risk. A thorough interior house inspection or deck inspection will identify any balustrade issues requiring attention.
The Queensland Department of Housing and Public Works has produced a Deck, Balcony and Window Safety Guideline which provides a useful guide for homeowners to ensure ongoing safety with regards to decks, balconies and stairways.