Stair nosings play a critical role in safety, accessibility, and compliance within New Zealand buildings. Whether it’s improving visibility, reducing slip risk, or assisting people with disabilities, stair nosings are referenced across several clauses of the New Zealand Building Code (NZBC).
Below, we break down the key requirements across accessible routes, escape routes, and access routes, and highlight best-practice compliance guidance.
An accessible route is required in every building with public access that spans more than one level. These routes are designed to enable people with disabilities to move safely and independently through a building.
Even where lifts are provided, the NZBC requires at least one accessible stairway forming part of an accessible route.
The NZBC Clause D1.3.4 and Compliance Document D1/AS1 reference NZS 4121:2001 – Design for Access and Mobility as the primary standard for accessible routes.
Key stair nosing-related requirements include:
Rounded leading edges
NZBC D1.3.4(h) and D1/AS1 4.1.7(a) require stair treads or nosings on accessible stairways to have rounded leading edges to avoid sharp edges.
NZS 4121:2001 Clause 8.1.1 specifies that any stair tread or floor covering not rounded between 5 mm (minimum) and 10 mm (maximum) requires a stair nosing.
Colour contrast
NZBC D1/AS1 4.1.7(b) requires leading edges or nosings to be colour-contrasted with the rest of the tread to improve visual detection.
The NZBC does not define a numeric contrast value, leaving interpretation to the building consent authority. To reduce ambiguity and ensure robust compliance, we recommend following AS 1428.1-2009, which provides clearer guidance on compliant luminance contrast. To meet this requirement, you’d be looking at a contrast of at least 30%. To help you meet contrast requirements, we’ve developed an LRV contrast calculator.
Tredsafe stair nosings are manufactured with a wide range of high-contrast inserts and profiles that align with these best-practice guidelines, helping remove uncertainty during inspections.
Escape routes are critical life-safety paths that must remain usable even when normal lighting fails.
NZBC Clause F6 – Visibility in Escape Routes outlines the requirements for ensuring specified features — including stairs — remain visible during a power failure.
F6.2 requires that specified features in escape routes be made reasonably visible by lighting systems, other systems, or both, when the main lighting fails.
While stair nosings are not explicitly mandated in all escape routes, enhancing stair visibility is a recognised and widely accepted compliance solution.
Tredsafe Lumitred photoluminescent inserts are designed specifically for this purpose. By using glow pigments that are co-extruded into the nosing, rather than surface-applied, they deliver:
Long-lasting visibility well beyond initial light loss
Consistent, all-round glow performance
Verified visual acuity for up to 300 minutes, exceeding standard test requirements by more than three times
This makes them a reliable option for meeting F6 visibility expectations in real-world emergency conditions.
An access route is required in every building with public access and provides a continuous path between the building exterior, interior spaces, and between spaces within the building.
The NZBC Compliance Document D1 – Access Routes sets out two key performance requirements relevant to stair nosings:
Slip resistance
NZBC D1.3.3(d) requires walking surfaces, including stair treads, to be slip resistant under normal conditions of use.
D1/AS1 4.1.4(c) refers to Table 2, which specifies a minimum Coefficient of Friction (COF) of 0.4, tested to AS/NZS 3661.1:1993, in both wet and dry conditions.
Visible leading edges
NZBC D1.3.3(g) requires stair treads to have a leading edge that can be easily seen.
Again, while “easily seen” is not numerically defined in the NZBC, aligning with AS 1428.1-2009 for contrast guidance is widely accepted as best practice.
Tredsafe stair nosing inserts are independently tested for slip resistance and available in a broad spectrum of contrasting colours, making it easier to satisfy both performance and visibility requirements across access routes.
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Stair nosings are not just a design detail — they are a key safety and compliance element across accessible routes, escape routes, and access routes in New Zealand buildings. While the NZBC sets performance-based requirements, adopting recognised standards and proven products can remove uncertainty and help achieve consistent compliance.
By choosing stair nosings that deliver rounded edges, high visual contrast, slip resistance, and emergency visibility, designers and building owners can confidently meet both regulatory expectations and real-world safety needs.
