Two methods, one standard
Both tests live inside AS 4663:2013, the Australian standard for measuring the slip resistance of existing pedestrian surfaces. Both are performed on site, on the floor as it is installed and worn. The difference is the condition each one simulates: one tests the floor wet, the other tests it dry. Because most floors face both states at some point, understanding what each result covers matters.
The wet pendulum test
The wet pendulum test is the primary on-site method in AS 4663:2013. A weighted arm swings a rubber slider across a surface that has been wetted with water, and the friction it meets is recorded as a British Pendulum Number. That number maps to a P classification from P0 to P5, where higher means more slip resistant when wet.
The swinging slider is meant to mimic the action of a heel striking a wet floor, which is where the majority of serious slips happen. Because it tests under wet conditions, it is the right method for any surface that gets wet or contaminated in normal use: entries in the rain, bathrooms, external paths, ramps, kitchens, and the area around drink stations and sinks.
Two rubber sliders are specified in the standard for different situations. A good report states which slider was used, along with the surface condition at the time, because both affect how the result should be read.
The dry floor friction test
The dry floor friction test is the standard's second on-site method. A motorised instrument drags a rubber slider across the dry surface and measures the coefficient of friction. Surfaces reaching a mean coefficient of friction of 0.40 or more are classified D1; below that is D0.
This test describes how a floor behaves when it is dry, so it is the right benchmark for surfaces that stay reliably dry in service, such as internal office floors, dry corridors and dry retail aisles. It deliberately says nothing about wet performance, which is why it should not stand alone for an area that ever sees water.
How to choose
The deciding question is simple: does this surface get wet or contaminated in normal use?
- Yes, or sometimes. Use the wet pendulum test. Entries, foyers near doors, bathrooms, pool surrounds, external ramps and paths, commercial kitchens, and any area exposed to spills, rain or cleaning water all belong here.
- No, it stays dry. The dry floor friction test is appropriate. Think interior corridors, office floor plates and dry storage areas that are protected from the weather and from spills.
- Not sure, or it depends on the day. Test wet. If there is any realistic chance the surface gets wet, the wet result is the one that reflects the real risk. Many buildings end up using both methods across different areas in a single visit.
This is why we conduct both methods. A single building often has dry office floors, a foyer that gets wet in the rain, and a bathroom that is wet several times an hour. One test method cannot honestly describe all three.
What the result is compared against
A classification on its own does not tell you whether a floor is safe. What matters is how the result compares to the recommended minimum for that location type. HB 198:2014, the Standards Australia handbook, sets out recommended minimum classifications for a wide range of specific locations, and an external ramp is expected to achieve far more grip than a dry internal corridor. The same P3 result can be comfortable in one place and a genuine problem in another. Our standards guide walks through the full classification tables.
A word on R ratings
You may also have seen R ratings on product datasheets. Those come from a laboratory ramp test on new material and cannot be measured on an installed floor, so they do not replace on-site wet pendulum or dry friction testing. We explain the difference in our guide to P ratings versus R ratings.
Not sure which test your site needs?
Tell us about your floors and how they are used, and we will scope the right method for each area before we visit. We test across Melbourne, Sydney and Brisbane.