Slip ratings explained: P, D and R classes and the standards behind them
Three documents shape slip testing in Australia. AS 4663:2013 says how to test an installed floor, AS 4586:2013 defines the classes, and HB 198:2014 recommends which class each kind of location should reach. Here is how they fit together.
AS 4663:2013: testing the floor you have
AS 4663 covers slip resistance measurement of existing pedestrian surfaces. It sets out two on-site methods. The wet pendulum test measures the friction a wetted floor offers a rubber slider and produces a mean British Pendulum Number. The dry floor friction test measures the coefficient of friction of a dry surface with a motorised tester. Both are carried out in place, on the floor in the condition it is in that day.
AS 4586:2013: the classes
AS 4586 is written for new pedestrian surface materials and describes four laboratory methods, but its lasting contribution is the classification scheme. Wet pendulum results are grouped into P0 to P5. Dry friction results are D0 or D1. The oil-wet ramp test produces R9 to R13, and the barefoot wet ramp test produces A, B and C. Because on-site pendulum results are reported in the same P classes, a floor's rating when new and its rating after years of use can be compared directly.
HB 198:2014: what each location should reach
The Standards Australia handbook is the piece that gives a number meaning. It lists location types and recommends a minimum class for each: P5 for steep external ramps, P4 for pool surrounds and commercial kitchens, P3 for entry foyers that get wet, and so on down to dry internal areas. A test result is only a pass or a shortfall relative to the recommendation for that specific location, which is why every entry in a Sliptest report states the target it was measured against.
The National Construction Code
For new work, the NCC requires stairs, ramps and landings in most building classes to achieve specified P or R classifications, and the relevant specification references AS 4586 for the testing of the materials. The NCC governs design and construction; once the building is occupied, WHS duties and HB 198:2014 take over as the practical benchmark for the floor's ongoing condition.
Why P ratings drift
The class boundaries are fixed but the floor is not. Traffic polishes, sealers fill texture, detergent film builds up and cleaning methods change. A new tile is tested in a lab in ideal condition. The same tile five years into service is a different surface, and only an on-site test tells you what it has become.
| Class | Slider 96 BPN |
|---|---|
| P5 | > 54 |
| P4 | 45 to 54 |
| P3 | 35 to 44 |
| P2 | 25 to 34 |
| P1 | 12 to 24 |
| P0 | < 12 |
| Class | Mean CoF |
|---|---|
| D1 | ≥ 0.40 |
| D0 | < 0.40 |
Recommended minimum class by location
A condensed view of the handbook's recommendations. The full tables run to many more location types and the handbook should be consulted for specification work. R classes apply to new materials only.
| Location | Wet pendulum class | Ramp class (new materials) |
|---|---|---|
| External ramps steeper than 1 in 14 | P5 | R12 |
| External ramps and paths, pool ramps and stairs into water | P4 or P5 | R11 to R12 |
| Pool surrounds, communal shower rooms and change rooms | P4 | B (barefoot ramp) |
| Commercial kitchens, serveries and food preparation areas | P4 | R12 |
| Entry foyers that receive rain, external stairs, hospital and aged care wet areas | P3 | R10 to R11 |
| Supermarket aisles, shopping centre malls and dry entry areas beyond the mat | P2 to P3 | R9 to R10 |
| Internal dry corridors, offices and dry lift lobbies | P1 to P2, or D1 dry | R9 |
Ratings questions
Is there a legal minimum slip rating?
For existing floors there is no single legislated number. Work health and safety law requires the risk to be managed, and HB 198:2014 is the reference that regulators, courts and insurers generally accept as the benchmark for what a location should achieve. New buildings must meet the slip classifications the National Construction Code sets for stairs, ramps and landings, which are specified in P and R classes.
What is the difference between a P rating and an R rating?
P ratings come from the wet pendulum test and apply to both new products and installed floors. R ratings come from a laboratory ramp test with oily contamination and apply only to new products. An installed floor cannot be given an R rating on site. If a specification quotes an R rating, the wet pendulum P class is what you can verify after installation.
Can a floor go from P4 to P2 without anything being done to it?
Yes. Wear, sealer build-up, polish and cleaning residue all reduce texture. A floor rated P4 when new commonly measures P2 or P3 after a few years of traffic, which is why installed floors are tested periodically rather than once.
What does D1 mean?
D1 is the dry floor friction class for a surface with a mean coefficient of friction of 0.40 or more. D0 is below that. HB 198:2014 recommends D1 for dry pedestrian areas.
Find out what class your floors are
Testing to AS 4663:2013 with every result compared with its HB 198:2014 target, and rectification by Premrest if a floor falls short.