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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.
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 22.214.171.124, 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 126.96.36.199 (reproduced below), are to be confirmed by testing in accordance with AS 4856.
NCC Table 188.8.131.52 Slip resistance classification application
|Ramp not steeper than 1:8||P4 or R10||P5 or R12|
|Tread surface||P3 or R10||P4 or R11|
|Nosing or landing edge strip||P3||P4|
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.
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.
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:
For finishes such as carpet, tiles, slate or vinyl, where the product is consistent and does not vary considerably as part of the manufacturing process, a laboratory test may be appropriate.
In this case, the supplier or manufacturer will have the necessary slip-resistance information and test reports to show that their product has been tested in accordance with AS 4586. Alternatively, an in-situ test can be conducted using the wet pendulum test as described in AS 4586, or a compliant tested nosing strip could be attached to the treads and landings.
For timber surfaces, where the manufacturer uses pre-coated finishes, they could have these pre- tested to AS 4586. Alternatively a compliant tested nosing strip could be attached to the treads and landings.
Timber stairs, particularly those with polished treads that are constructed on-site, could have a coating applied to the treads to meet the necessary slip-resistance requirements.
HIA is aware that there are a number of proprietary clear coating products available that have been tested and can be used as a coating to the timber treads to meet both the wet and dry surface conditions requirements – i.e. for both internal and external timber stair treads.
Alternatively, an in-situ test can be completed once a finish has been applied to confirm compliance with the slip resistance requirements.
As an alternative to a tread or surface coating the NCC allows the application of nosing strips, adhesive tapes or similar to be used to satisfy the slip resistance ratings.
With all of the above means available to satisfy the requirements relating to material selection it may be necessary to discuss these requirements with your client and the available options as it may narrow product selection.
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 184.108.40.206 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:
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.
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.
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.
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.
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