All balustrades in Australia are required to comply with the Building Code of Australia (BCA) Parts 3.9.1 and 3.9.2, Volume 2 and Australian Standard 1170.1. These codes are specific to safety issues pertaining to movement of humans between different levels of a building by use of stairs or ramps. The code also applies to raised platforms such as patios, balconies, verandas, terraces and so on.
To prevent humans from falling off inclined surfaces or raised horizontal surfaces, a continuous balustrade should be erected at the edge of a stairway, raised floor, inclined floor, hallway, corridor, balcony, pathway, veranda, patio, mezzanine or path used by humans that is not bounded by a wall or any surface that is more than 1 m above finished ground or adjoining floor level.
The height of the balustrade is to be measured from the finished floor surface. Such finished floor surface to include tiles, carpet etc.
Irrespective of pressure exerted, a balustrade needs to be stiff so it does not buckle or break under pressure exerted. A balustrade can have a non-slip handrail.
THE BCA regulations specify the height of a balustrade built in Australia to be not less than:
1. 1m above the finished floor and 4m where there exists a possibility of a falling through an open window.
2. Where a balustrade is provided along the inside edge of a landing, the height shall be 865mm above the floor of a landing to a ramp or stair and is not more than 500mm long.
3. Where the balustrade height changes or needs to change from 865mm on the stair flight or ramp to 1m at the landing, a transition zone should be incorporated.
BCA Rules further specify:
I. A balustrade has to be constructed in such a manner that a child or adult cannot fall through or over the balustrade. The balustrade needs to prevent a child crawling through them. Any openings in a balustrade must be less than 125mm. This space is tested above the nosing line.
II. A balustrade should be built strong enough to resist pressure from a person leaning against it and also strong enough to as to not buckle if an adult human sat on it.
III. BCA regulations AS 1170.1, specify loading forces that the balustrade must be designed to be strong enough to withstand a point load of 0.6kN and also strong enough to accept an evenly distributed load of 0.4kN applied outward, inward or downward on the handrail.
BCA regulations AS 1170.1, is intended to ensure that the balustrade is able to withstand the impact of a person falling against it (point load) and strong enough not to buckle or collapse as a result of people leaning against it (distributed load). It also specifies that the handrail must also be able to accept similar loads.
IV. AS 1604 of the BCA rules specify that posts, handrails, newels and balusters should be constructed out of naturally durable Class1 or Class2 timber species. This includes spotted gum, blackbutt, ironbark, Merbau, Jarrah and Kwila. It further specifies that any sapwood present must be treated to H3 standard i.e. the strength of the timber should be reduced due to infection or internal defects.
V. As regard to fitments, metal connectors, nails, bolts, screws and brackets, the BCA rule AS3566 specifies that these should be hot dipped galvanised or Class 3 corrosion resistant. Where there is increased danger of rusting (such as coastal environments), BCA specifies that stainless steel or equivalent corrosion resistance metal components be used.
VI. All nail and bolt holes should be covered with exterior grade wood filler. Similarly, all timber-to-timber joints should be covered with a preservative coating and joints should be coated with Alkyloid primer. Timber should be finished with a minimum of two top coats of exterior stain or paint.