This Safety Step post is a plain English examination and comment on how the Australian Standard AS 1428.1 impacts on the design and performance of stair nosings.
What is AS1428.1?
The full title is Australian Standard Design for Access and Mobility Part 1: General requirements for access – new building work.
This Standard sets out minimum design requirements to provide access for most people with disabilities and addresses a wide range of building design elements.
Clause 11 of the Standard specifically addresses requirements for stairways and stair nosings and in this regard focuses almost entirely on promoting luminance contrast at the leading edge of step treads together with the avoidance of overhang at the front of stair treads.
Is AS1428.1 a mandatory requirement?
The actual Standard has no mandatory power, however the Building Code of Australia (BCA) adopts AS1428.1 and requires mandatory compliance with that Standard and is enforceable by law. Clause D3.3(a)(ii) of the BCA states that in any new development, and in major refurbishment all stairways (except a fire stairway) must comply with Clause 11 of AS1428.1.
What does AS1428.1 say about stair treads and stair nosings?
- Stair nosings are not allowed to project beyond the face of the riser.
- Stair nosings must be continuous across the full width of the stair tread.
- Stair nosing profiles may have a sharp intersection or a radius up to 5mm, or up to a 5mm x 5mm chamfer at the tread/riser intersection.
- A luminance contrast strip that provides a strong visual clue of the tread/riser intersection must be included.
- The strip needs a luminance contrast of at least 30% with respect to the background material.
- The luminance contrast strip must be between 50mm and 75mm wide and cannot be set back from the tread/riser
- intersection by more than 15mm.
- When located at the front of a stair nosing, the luminance contrast strip cannot extend down the riser more than 10mm.
- Stair risers must be opaque.
What is the definition of ‘stairway’?
to answer the question, ‘When is a stairway a stairway‘, two (or more) continuous steps would be considered a stairway and will trigger AS1428.1 requirements for TGSIs, handrails, and stair nosing.
Are all stairways included in AS1428.1?
What is “luminance contrast”?
Luminance contrast is defined in Standard 1428.1 as ‘the light reflected from one surface or component, compared to the light reflected from another surface or component’. It is not simply the difference in the colour contrast but the difference in the light reflective properties of each colour.
Luminance contrast is preferred to colour contrast as it highlights the difference in the light/dark qualities of two adjoining surfaces rather than just their colours”.
In practical terms, this is what it’s all about:
Below are examples of non AS 1428.1 compliant stairs, not achieving the required minimum 30% luminance contrast or minimum strip dimensions and also not meeting anti-slip requirements:
Answers to frequently asked questions.
Q. Is the depth of the stair nosing limited to 10mm at the front like this?
A. Absolutely not. The body of the stair nosing can extend any distance down the riser. If the luminance contrast strip is located at the front of the stair nosing then that strip cannot extend down the riser more than 10mm. This limitation is to avoid confusing the location of the leading edge of the tread. The body of the stair nosing, so long as it is clearly diferentiated from the luminance contrast strip, can extend to any depth on the riser, like this:
Q. Does the luminance contrast strip have to be in one piece?
A. The AS 1428.1 Standard prefers the strip to be one unbroken width, between 50mm and 75mm wide to maximise the contrast effect, however minor interuption to that strip is tolerated provided that the interuption does not adversely effect the luminance contrast effect. As an example, a 50mm strip may be presented as two 25mm strips with a very thin division between but not presented as five 10mm strips with bold divisions between.
Q. What is meant by ‘stair nosings cannot extend beyond the front of the tread’?
A. A stair nosing is permitted to fold tightly down the front of the stair riser after forming a sharp intersection at the tread/riser intersection, but the stair nosing should not extend outward or form an overhang at the front of the tread.
Q. Can an AS1428.1 nosing also contain a glow in the dark feature?
A. Yes it can so long as the glow feature is located correctly within the nosing. To remain compliant with AS1428.1 the luminous contrast strip cannot be situated further than 15mm back from the front edge of the tread so any glow feature should sit either immediately in front of or immediately behind the contrast strip while retaining the contrast strip width between 50mm and 75mm.
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