This document is to help homeowners and specifiers interpret the NZ building code and ensure the perfect tile makes its way into any situation with safety in mind.
This is a guide only. The building code itself is vague on detail so assumptions and a common sense approach based on expected usage is recommended. Tile Depot are here to help but take no responsibility for your project where many site specific factors are to be considered.
So what does the law say?
The only reference to slip resistant requirements in the Building code is AS/NZ3661.1 section D1 - Access Routes. D1/AS1 is a publication of Acceptable Solutions to ensure compliance with Section D and it now covers a wider scope than just accessways particularly for commercial situations.
D1/AS1 now refers to both Pendulum testing (SRV not less than 39) as well as Ramp testing which provides an R value (R9, R10, R11). The two testing methods are quite different and the result of one does not always directly correlate to the other.
What are these testing methods?
The pendulum slip test consists of a weighted foot with a test slider that swings down and slides across the surface wetted with water. The weighted foot comprises a spring loaded rubber test slider that exerts a prescribed force over the tile as it slides across the surface. The higher the number, the lower the risk of slipping.
In certain situations, New Zealand rules require tiles to have an SRV of 39 or higher. The problem is that tiles rated P3 can fall anywhere between SRV 35–44. This means some P3 tiles meet the magic 39 number, and some don’t. Because of this uncertainty, people often play it safe and choose P4 tiles instead, even when a suitable P3 option exists.
The Ramp Test involves a subject walking across the tiles under scrutiny, which are in turn fixed to an adjustable ramp. The subject wears specified safety footwear, and the surface of the tiles are covered in an oil. The angle of the ramp is increased until the subject can no longer maintain balance, and at this point the angle of the ramp is recorded.
The steeper the angle, the higher the slip resistance, and the higher the score. The tile is awarded an “R – rating” between R9 and R13, with the higher rating indicative of higher resistance. The below table shows the risk profile for each rating. Note that the lowest score possible is R9.
One of the disadvantages of this procedure over any other is that it needs to be carried out in a laboratory. Often situations arise, perhaps where there’s been an accident or a claim, where measurements need to be taken after installation. Clearly this ramp test is of no benefit in these circumstances and there are no ramp testing facilities in New Zealand.
Can I convert an R rating to a P rating and vice versa?
“No” is the short answer, the testing methods are very different and some tiles perform higher on one method over the other. In saying that the industry works on the below comparisons as a guide only. We always recommend checking a tiles compatibility to the desired application prior to installation. Slip test reports can be provided for specific projects.
Where do I need to use an ‘antislip’ tile - Residential?
The grey italic boxes below are exerpts from D1/AS1 Acceptable solutions:
RESIDENTIAL SITUATIONS
Accessways: Only the approach to the main entrance and not inside the house. A Pendulum test rating of 39 or higher is required. We recommend a minimum P4 pendulum or a ramp test rating of R11.
Internal living areas: No slip rating is required. Living areas, Bathrooms & Kitchens are considered dry under normal circumstances.
2.1.2 For level access routes (including level accessible routes) expected to become wet with water in normal use, walking surfaces shall:
a) Have an SRV classification of not less than 39 from the wet pendulum test method of AS 4586
COMMENT: The most common area of buildings that becomes wet under normal use is at entrances where water can be tracked from the footpath.
The exceptions are:
a) situations where safety matting is provided as described in 2.1.5
b) for housing this requirement applies only to the access route on the approach to the main entrance and not inside that entrance and not on the approach to other entrances. The internal access routes of housing, including kitchens and bathrooms, shall be assumed to be dry in normal use.
Swimming pools surround: The immediate pool surround requires a minimum P4 or R11. This is a recommendation only.
External paths, patios, verandahs: No guidance given but refer to Table 3B from HB 198 (shown on page 6) which recommends a minimum P4 or R11 for areas with less than 1:14 slope.
Sloping access including stairs: When a slope increases there is a logical requirement for an increased coefficient of friction (COF). Again, no requirement given but for guidance refer to Table 3A shown on page 7.
2.1.5 For sloping access routes including stairs AS 4586 Appendix F shall be used to derive the appropriate slip classification for walking surfaces at various slopes. A P4 rating from the wet pendulum test is also acceptable for stairs and for ramps not steeper than 1:12
Where do I need to use an ‘antislip’ tile - Commercial?
COMMERCIAL SITUATIONS
Accessways expected to become wet during normal use: The approach to and transition zone into a public building requires a 39 Pendulum test or R11 ramp test rating. Internally this can be achieved by providing a mat of at least 1.8mtrs length, if an antislip tile is not used. (ref D1/AS1 2.1.6)
2.1.6 Except in housing, the transition zone between any part of the access route which is intended to remain dry under normal usage and that part of the access route which may become wet during normal usage shall be provided with:
a) Water absorbent matting across the width of the effective walkway with a sufficient dimension in the direction of the pedestrian traffic to remove water which may be tracked by footwear, or
b) An extension of the wet slip resistant walking surface for sufficient distance from the point at which water can be tracked indoors (normally from the entrance portal) to allow water to be shed from footwear, or
c) A combination of a) and b) above.
Sloping access including stairs: ref D1/AS1 2.1.5. As per domestic criteria.
Other Commercial Situations: We recommend using Table 3B from HB198 (overpage) for appropriate Pendulum or R rating. This is a valuable resource for tile specifiers and we encourage our staff and clients to use this as a reference for any commercial project.
2.1.4 For industrial and commercial situations, AS 4586 Appendix D is an acceptable method of determining the slip resistance of walking surfaces that may be contaminated by oils and similar slip-inducing materials in use.
COMMENT:
HB 198 in Table 3B lists suggested R-values for a range of commercial situations
Table 3B HB198 - Guide to specification and testing of slip resistance of pedestrian
surfaces.
* ABC ratings are a barefoot ramp test not always available from suppliers, pendulum to be used where not available.
**The slip resistances of pedestrian surface materials set out in Table 3B are intended as guidance in the context of design for pedestrian safety, taking account other factors including abnormal wear, maintenance, abnormal contamination, the presence (or otherwise) of water or other lubricants, the nature of the pedestrian traffic (including age, gait and crowding), the footwear (or lack thereof), slope, lighting and handrails.
Commercial stair nosings, landings and ramps
Table 3A
HB 198:2014
MINIMUM WET PENDULUM TEST OR OIL WET INCLINGING PLATFORM CLASSIFICATIONS THAT ARE DEEMED TO SATISFY THE BUILDING APPLICATIONS IN THE NATIONAL CONSTRUCTION CODE (AUSTRALIAN STANDARD)
Disclaimer: This document has been produced by Tile Depot to assist staff, customers and specifiers with the selection of suitable tiles for suitable spaces. This is our interpretation of the NZ building code and supporting industry documentation. Ultimate responsibility for tile selection remains with the customer and or specifier and we take no responsibility for the compatability of tiles chosen. Factory slip test reports are often provided on the initial production and are subject to change over time without notice. Our best endeavours are taken to keep this information current and available. Standards and regulations are subject to change.
