Part 3.9.2 Barriers And Handrails
Appropriate Performance Requirements
- Where an alternative barrier is proposed as a Performance Solution to that described in Part 3.9.2, that proposal must comply with—
22.214.171.124 Barriers to prevent falls
A continuous barrier must be provided along the side of—
any roof to which general access is provided; and
any stairway or ramp; and
a floor, corridor, hallway, balcony, deck, verandah, mezzanine, access bridge or the like; and
any delineated path of access to a building,
if the trafficable surface is 1 m or more above the surface beneath (see Figure 126.96.36.199).
The requirements of (a) do not apply to—
a retaining wall unless the retaining wall forms part of, or is directly associated with a delineated path of access to a building from the road, or a delineated path of access between buildings; or
a barrier provided to an openable window covered by 188.8.131.52.
184.108.40.206 Construction of barriers to prevent falls
The height must not be less than 865 mm above the nosings of the stair treads or the floor of a ramp.
The height must not be less than—
Openings in barriers (including decorative balustrades) must be constructed so that they do not permit a 125 mm sphere to pass through it and for stairs, the opening is measured above the nosing line of the stair treads.
openings are constructed so that they do not permit a 300 mm sphere to pass through; or
where rails are used, the barrier consists of a top rail and an intermediate rail, with the openings between rails not more than 460 mm.
A barrier, except a window serving as a barrier, must be designed to take loading forces in accordance with AS/NZS 1170.1.
A window forming part of a barrier is not required to comply with AS/NZS 1170.1 as it is exempted by 220.127.116.11(e). However, a window serving as a barrier must comply with the glazing assembly provisions of AS 2047 or AS 1288. These provisions consider the wind loading on the glass and human impact requirements.
For floors more than 4 m above the surface beneath, any horizontal elements within the barrier between 150 mm and 760 mm above the floor must not facilitate climbing.
For horizontal wire systems—
when measured with a strain indicator, it must be in accordance with the tension values in Table 18.104.22.168; or
must not exceed the maximum deflections in Table 22.214.171.124.
For non-continuous vertical wire systems, when measured with a strain indicator, must be in accordance with the tension values in Table 126.96.36.199 (see Note 4).
For continuous vertical or continuous near vertical sloped wire systems—
must have wires of no more than 2.5 mm diameter with a lay of 7×7 or 7×19 construction; and
changes in direction at support rails must pass around a pulley block without causing permanent deformation to the wire; and
must have supporting rails, constructed with a spacing of not more than 900 mm, of a material that does not allow deflection that would decrease the tension of the wire under load; and
when the wire tension is measured with a strain indicator, it must be in accordance with the tension values in Table 188.8.131.52 and measured in the furthermost span from the tensioning device.
- For the purpose of this clause, a wire barrier consist of a series of tensioned wire rope connected to either vertical or horizontal supports serving as a guard to minimise the risk of a person falling from a roof, stairway, raised floor level or the like.
- A wire barrier excludes wire mesh fences and the like.
- To assist in the application of 184.108.40.206(g), the following terms have been defined:
- Continuous — where the wire spans three or more supports.
- Non-continuous — where the wire only spans between two supports.
- Pulley block — a device consisting of a wheel in which a wire runs around to change its direction.
- Permissible deflection — is the allowable bending of the wire.
- Support rails — are horizontal components of the barrier system that span across the top and bottom to provide structural support.
- and 220.127.116.11 contains tension requirements for wires in vertical wire barrier systems with varying post spacings, wire spacings and wire types. The figures contained in the table were derived from testing the spacing combinations in order to prevent the passage of a 125 mm diameter solid cone penetrating between the wires at a predetermined force.
- Care needs to be taken to ensure that wire tension will be maintained during the life of the barrier. In some situations, it may be necessary to incorporate "lock-off" devices to prevent loosening of the wire.
- Likewise, if a threaded anchor bears against a soft wood post or rail, the anchor may indent the post or rail, thus loosening the wire.
- Temperature effects on the tension of the wire may be significant but there is little that can be done to allow for temperature variation in service. The shorter the wire span, the lesser the effect will be.
- Stainless steel wire with a lay of 1×19 has the greatest elastic modulus and will take up the same load with less extension than equivalent wires with other lays.
- Sharp ends of wires at terminations and swages need to be removed for the safety of children and other people. No wire end should protrude more than half the diameter of the wire from the swage or termination fitting.
Table 18.104.22.168 WIRE BARRIER CONSTRUCTION – REQUIRED TENSION FOR STAINLESS STEEL HORIZONTAL WIRES
|Clear distance between posts (mm)|
|Wire dia. (mm)||Lay||Wire spacing (mm)||Minimum required tension in Newtons (N)|
Table 22.214.171.124 CONTINUOUS WIRE BARRIER CONSTRUCTION – REQUIRED TENSION FOR VERTICAL OR NEAR VERTICAL STAINLESS STEEL WIRES
|Wire dia. (mm)||Lay||Widest spacing between wires (mm)||Maximum clear spacing between rails (mm)|
|Required tension in Newtons (N)|
Table 126.96.36.199 WIRE BARRIER CONSTRUCTION – MAXIMUM PERMISSIBLE DEFLECTION FOR STAINLESS STEEL WIRES
|Clear distance between posts (mm)|
|Wire dia. (mm)||Wire spacing (mm)||Minimum required tension in Newtons (N)|
A glass barrier must comply with AS 1288.
|Note: For the purposes of this Figure, a 125 mm sphere must not pass between rails or through the opening when measured above the nosing line.|
BARRIERS — WHEN REQUIRED
Handrails to a stairway or ramp must—
be located along at least one side of the flight or ramp; and
be located along the full length of the flight or ramp, except in the case where a handrail is associated with a barrier the handrail may terminate where the barrier terminates; and
have the top surface of the handrail not less than 865 mm vertically above the nosings of the stair treads or the floor surface of the ramp; and
have no obstruction on or above them that will tend to break a handhold, except for newel posts, ball type stanchions, or the like.
The requirements of (a) do not apply to—
a stairway or ramp providing a change in elevation of less than 1 m; or
a landing; or
a winder where a newel post is installed to provide a handhold; or
a stairway or ramp in a Class 10 building.
- A barrier top rail may be suitable as a handrail if it meets 188.8.131.52.
- A handrail is only required on one side of the flight or ramp.
- The handrail may extend the full length of the flight or ramp except where the handrail is associated with the barrier, in which case the handrail can terminate where the barrier is allowed to terminate. This would allow for the barriers of geometric stairways such as elliptical, spiral, circular or curved stairways to finish a few treads from the bottom of the stairway.
- An example of where a handrail is not required would be a flight consisting of 5 risers as the change in elevation is less than 1 m.
- A handrail is not required for winders if a newel post is installed to provide a handhold.
184.108.40.206 Protection of openable windows
A window opening must be provided with protection, if the floor below the window in a bedroom is 2 m or more above the surface beneath.
Where the lowest level of the window opening is less than 1.7 m above the floor, a window opening covered by (a) must comply with the following:
The openable portion of the window must be protected with—
a device capable of restricting the window opening; or
a screen with secure fittings.
not permit a 125 mm sphere to pass through the window opening or screen; and
resist an outward horizontal action of 250 N against the—
window restrained by a device; or
screen protecting the opening; and
have a child resistant release mechanism if the screen or device 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—
where the floor below the window is 4 m or more above the surface beneath if the window is not covered by (a).
A barrier covered by (c) must not—
permit a 125 mm sphere to pass through it; and
have any horizontal or near horizontal elements between 150 mm and 760 mm above the floor that facilitate climbing.
The intent of 220.127.116.11 is to limit the risk of a person (especially a young child) falling through an openable window. Where the floor level below an openable window is less than 2 m there are no specific requirements. For an openable window in a bedroom 2 m or more above the surface beneath, openable windows are required to restrict passage of a 125 mm sphere using any one of the following design solutions:
- The window be designed such that any opening does not allow a 125 mm sphere to pass through (e.g. louvres).
- The window be 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. The restricting device must be capable of restricting a 250 N force when directed against the window such as a casement window or in attempting to push a sliding window open. An internal screen with similar parameters may be installed.
- The window be fitted with 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.
If the openable part of the window is at least 1.7 m above the floor, no further protection is required.
relates to a screen or window restricting device protecting an openable window in a bedroom. 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. In these situations the unlocking device must be child resistant.
Child resistance could be achieved by the need to use a tool, key or two hands.
There are a number of hardware options available. Short chain winders and barrier screens will allow windows to comply with this requirement. Sliding window locks may lock a sash so a 125 mm sphere cannot pass through. Where provision is made to fully open the window beyond 125 mm then the child resistant release mechanism is required in addition to the device resisting a 250 N force as required by 18.104.22.168(b)(ii)(B).
relates to the height of a barrier under an openable window in a room that is not a bedroom in a Class 1 building or a window in a Class 10 building.
The term "window" is not italicised in 22.214.171.124 and as such, is not restricted to the definition of "window" in the BCA. The reason for this is to also capture windows that may let in air but not light, e.g. metal louvres. A metal louvre or openable panel would not fit in the BCA definition of window but is subject to the window barrier provisions.