The short version
P ratings and R ratings both grade slip resistance, but they come from different tests, use different contaminants, and answer different questions. P ratings come from the wet pendulum test and can be measured on a floor that is already installed. R ratings come from a laboratory ramp test on a sample of new material and cannot be measured on a floor in place. In Australia, the classification that describes how your actual floor performs today is the P rating, not the R rating printed on the original product datasheet.
Where each rating comes from
The difference makes a lot more sense once you know how each number is produced.
- P ratings (wet pendulum test). A portable pendulum swings a rubber slider across a wetted surface. The friction it meets is recorded as a British Pendulum Number, which maps to a classification from P0 to P5. Because the instrument is portable, it can test the floor exactly where it is, in the condition it is in. This is one of the two on-site methods in AS 4663:2013, the Australian standard for existing pedestrian surfaces.
- R ratings (oil-wet inclining platform test). An operator walks back and forth on a sample of the surface material while it is coated in oil and progressively tilted. The angle at which they lose grip gives a classification from R9 to R13. This is a laboratory method carried out on new material, and it appears in AS 4586:2013, the Australian standard for classifying new surface materials.
So one number describes a water-wetted floor in your building; the other describes an oil-wetted sample in a lab. They are not interchangeable, and there is no reliable formula to convert one into the other.
Why R ratings show up so often
R ratings dominate product literature, especially for imported tiles, because the ramp test is common across Europe. When a supplier or specifier chooses a floor finish for a new project, an R rating is a convenient way to compare products before anything is installed. That is a legitimate use. The problem starts when an R rating from a brochure is later treated as proof that the installed floor is safe.
An R rating describes the material as it left the factory. It says nothing about how that surface was laid, how it has worn, what sealer or polish has gone over it, or how your cleaning regime has changed it. Two identical tiles can behave very differently once one has spent three years in a busy foyer.
Which rating applies to your situation
A simple way to decide:
- Specifying a new floor? R ratings and the P ratings from AS 4586 laboratory testing both help you compare materials before you buy. Your architect or specifier will usually work to the classifications called up by the National Construction Code, which references AS 4586 for elements such as stairs and ramps.
- Managing a floor that is already down? The rating that matters is the P classification from an on-site wet pendulum test to AS 4663:2013. It measures the real surface, not the datasheet. For areas that stay reliably dry, the dry floor friction test gives a D classification instead.
For the full breakdown of each classification system, including the D ratings from the dry floor friction test, see our guide to Australian slip resistance standards.
Can you compare a P rating to an R rating?
Not directly, and you should be wary of any chart that claims to. Published conversion tables between R and P classifications exist, but they are approximate at best because the two tests use different contaminants, different motions and different surfaces. A tile that carries an impressive R rating can still return a disappointing P result once installed and tested wet, particularly if it has been sealed or polished. If a decision rests on how a real floor performs, the honest answer comes from testing that floor, not from converting a laboratory figure.
What this means for building owners and managers
If your only evidence that a floor is slip resistant is an R rating on an old product spec, you do not actually have current evidence about that floor. Under Australian work health and safety duties, those in control of a workplace or public premises are expected to manage slip risk so far as is reasonably practicable, and objective on-site testing against HB 198:2014 guidance is the accepted way to show it. A brochure from the day of installation does not demonstrate the floor is safe now.
This is exactly the gap on-site testing fills. A wet pendulum test tells you where your floor sits today, against the guidance for its specific location, so you can act on real numbers rather than a factory figure.
Get the rating that reflects your real floor
If you are holding a product datasheet and wondering whether the floor still lives up to it, that is a question we answer every day across Melbourne, Sydney and Brisbane. Send us the details and we will scope the right test.