Australian Standards AS 1428.1-2009 Design for access and mobility-General requirements for access - New building work specifies a minimum of 30% luminance contrast requirement between the stair nosing and the surrounding substrate colour. This assists all pedestrians, especially those with visual impairment, to safely navigate the edge of the step. Highlighting the nosing on steps is important for all stairs but stairs which are poorly lit e.g. (fire stairs and external stairs at night) are of significant danger to pedestrians.
In basic terms, a product with dimensions ranging between 50 - 75mm on the tread and not greater than 10mm on the riser, while offering a minimum of 30% contrast to the surrounds, is required.
Why only 10mm on the front riser ?
We have literally had hundreds of people ask this question to us over the last decade. One reason for the short/10mm return at the front is that longer returns were found to be a potential trip hazard for those with disability and prone to dragging their legs while ascending stairs.
'Legacy' stair nosing which have noses/front returns longer than 10mm (say 30mm for example) are still in circulation (we still produce them) but they should only be used in very special circumstances and when permission has been expressly given by authorities to do so.