Understanding the NCC slip resistance requirements for stairs

Why were the slip resistance provisions introduced? 

The NCC has required stair treads or stair nosings in domestic construction (Class 1 and 10 buildings) and pedestrian ramps, stair treads or stair nosings and landings in residential and commercial construction (Class 2-9 buildings) to be ‘slip resistant’ or ‘non-slip’ for many years. However, the NCC did not define or quantify the level of slip resistance required for each of these circumstances. 

This meant that it was up to the builder and the relevant building certifier/surveyor as part of the building approval process to use discretion as to what they considered a ‘slip resistant’ surface to be. This could be satisfied in several ways using various applications and methods. 

NCC 2014 adopted AS 4586:2013 Slip resistance classification of pedestrian surface materials, which includes new methods to quantify the level of slip resistance. 

The information here focuses on NCC Volume Two requirements, but the requirements are similar to those in Volume One for a Class 2-9 building.

NCC requirements for stairs and ramps

The relevant NCC Performance Requirement for slip resistance of stairs is P2.5.1(b)(iv), which states that:

‘A stairway must — have slip-resistant walking surfaces on ramps, and on stairway treads or near the edge of the nosing.’

The intent of the provision is to minimise the risk of people slipping and injuring themselves on stairways and ramps.

The  Deemed-to-Satisfy Provisions that  demonstrates compliance with this Performance Requirement is 3.9.1.4, which applies to stair treads, ramps and a landing where the edge leads to the flight below.

For a stair tread, the NCC requires either the whole surface of the tread or a nosing strip to the tread to meet the prescribed surface resistance classification.

For a ramp that is serving the house or within the house, the whole surface of the ramp is required to meet the prescribed surface resistance classification.

For landings, the NCC requires either a nosing strip to the edge leading to the flight below or a surface to a width of 190mm from the stair nosing to meet these requirements.

The prescribed surface resistance classifications as per NCC Table 3.9.1.3 (reproduced below), are to be confirmed by testing in accordance with AS 4856. 

NCC Table 3.9.1.3 Slip resistance classification application

It should be noted that the NCC requirements only apply to the slip resistance requirements to stair treads, ramps and landings and not to other areas within the building or external to the building. This also applies to the NCC referencing of AS 4586 – i.e. it doesn’t apply to areas other than what is referenced for in the NCC.

Surface conditions classifications

AS 4856 is a testing standard that classifies the pedestrian surface for slip resistance in both dry and wet surface conditions. The NCC nominates the value as determined by the Standard for areas that commonly experience dry conditions and areas that commonly experience wet conditions (the latter would generally be external areas or those areas that are exposed to external elements).

AS 4586 contains two tests that are applicable to the NCC provisions – a wet pendulum test and an oil-wet inclining platform test.

The wet pendulum test provides a classification range of P0 to P5 and can be tested in-situ or in a laboratory. The oil-wet inclining platform test provides a classification range of R9 to R13 and is a laboratory-based test.

Selection of materials

The main consideration in relation to the new requirements is to ensure that materials used and/or finishes applied to stair treads, landings and pedestrian ramps will satisfy the NCC slip resistance values.

In the past in satisfying the requirements, particular materials were considered based on their properties and common use to be suitable materials and provide a degree of slip resistance.

However, given the changes to the NCC, building certifiers/surveyors and approval authorities are now requiring evidence of suitability that stair treads, landings and pedestrian ramps satisfy the requirements.

The following provides a summary of the requirements and how they applies to commonly used materials: 

Performance Solutions 

The NCC is a performance-based code where the Performance Requirements are the mandatory requirements that must be satisfied to achieve compliance with the NCC. 

Compliance with the Performance Requirements can be demonstrated by developing a Performance Solution, by following the Deemed-to-Satisfy Provisions (outlined above), or a combination of both. 

Therefore, the Deemed-to-Satisfy Provisions of Part 3.9.1.4 are only one means of satisfying the relevant Performance Requirement P2.5.1(b)(iv) for slip resistance of stairways and ramps. 

A Performance Solution could be used to demonstrate compliance with P2.5.1(b)(iv), which may include using an alternate international testing standard, which provides a comparative level of slip resistance ratings as those prescribed in the Deemed-to-Satisfy Provisions. 

To determine that a Performance Solution complies with the Performance Requirements, one (or a combination) of the following NCC Assessment Methods, must be used:

• Documentary evidence (as prescribed in NCC A.5.2) to support that the material, form of construction or design meets the Performance Requirement
• Verification Methods, which may be a method prescribed in a Standard not called up by the NCC
• Comparison with the DTS Provisions, or
• Expert judgement.

However, it should be noted that the suitability of any Performance Solution is subject to acceptance by the building certifier/surveyor and it is therefore recommended that you discuss the proposed solution with the building certifier/surveyor for the project.

How to check products are slip resistant

Before specifying or purchasing materials to be used to satisfy the slip resistance requirements, you should ensure that you check the product information to determine the suitability of the material or product.

The product information may include test reports or verification certificates that indicate the testing undertaken, the results of those tests, any limitations or conditions on the use of the product and how long the certificate may be valid for.

If the manufacturer or supplier doesn’t have this information available, you may want to request this verification prior to using the product or material.

Who can undertake testing?

There are a number of organisations that can undertake testing in accordance with AS 4586, to verify the slip-resistance classification of a surface or material.

Some organisations are accredited by the National Association of Testing Authorities (NATA) to specifically undertake slip-resistance testing. Organisations accredited by NATA are recognised by the NCC to be Accredited  Testing Laboratory under the evidence of suitability provisions.

Information on NATA-accredited testing organisations is available on the NATA website.

Test reports based on earlier version of the Standard

AS 4586 was revised in 2013 from the previous 2004 edition. However, the NCC provides that if a test report was based on the previous edition and issued prior to the 2013 edition being referenced, the values determined under the previous Standard remain valid.

The P5, P4 and P3 classifications under the 2013 Standard are an equivalent to the V, W and X classifications in the 2004 Standard respectively. 

To find out more, contact HIA’s Building Services team.

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