Tile slip ratings tell you how much grip a floor tile offers underfoot, measured through standardised laboratory and on-site tests. The three you will meet on UK jobs are the R rating (R9 to R13, shod ramp test), the ABC barefoot class (DIN 51097), and the Pendulum Test Value or PTV, which is the figure the Health and Safety Executive actually relies on. Getting these right is the difference between a floor that passes inspection and one that turns into a compensation claim.
This guide is written for tradesmen specifying and laying floors, and for anyone training into the trade who needs to read a tile datasheet properly. It covers what each rating means, where it comes from, and how to specify slip resistant flooring that holds up under UK regulation.
What are tile slip ratings?
Tile slip ratings are classifications that grade a floor surface by its resistance to slipping, usually under wet or contaminated conditions. Because a dry tile rarely causes a slip, the useful numbers are the wet ones. Different tests exist because different environments matter: a factory floor covered in oil behaves differently from a barefoot pool surround, so the industry uses more than one scale.
The point that catches people out is this: no single rating covers every situation. An R rating alone does not clear a barefoot wet area, and a barefoot class tells you nothing about grip in work boots. Always read the datasheet for the test that matches how the floor will actually be used.
R ratings (DIN 51130): the shod ramp test
The R rating is the most quoted anti slip rating and comes from the German ramp test, DIN 51130. A tester wearing standardised cleated safety boots walks up and down an inclined platform coated with motor oil while the ramp angle increases. The angle at which safe walking stops sets the rating.
The scale runs from R9 to R13, where R9 is the slipperiest and R13 the least. There are no such categories as R1 to R8. The HSE defines each rating by the slip angle recorded on the ramp:
- R9: slip angle 6 to 10 degrees, the lowest grip band.
- R10: slip angle 10 to 19 degrees.
- R11: slip angle 19 to 27 degrees.
- R12: slip angle 27 to 35 degrees.
- R13: slip angle above 35 degrees, the highest grip band.
Here is the part that matters on site. An R rating is not proof that a floor is safe for a given area. Each rating covers a wide band, so a tile at the bottom of R10 may be barely different from one at the top of R9. The UKSRG is explicit that you cannot say an R10 will be suitable as a slip resistant floor on the rating alone. Two further cautions:
- The oil contaminant is aggressive: an R rating flatters a tile compared with how it performs against plain water, so treat it as a starting point.
- The R rating is a shod test: it says nothing about barefoot grip, which is a separate test entirely.
Use the R rating to shortlist, not to sign off. The floor’s real performance is settled by an on-site PTV, covered below.
DIN 51097: the ABC barefoot classification
For wet barefoot areas you need the ABC class, tested under DIN 51097. The setup mirrors the shod ramp test, but water with a wetting agent replaces the engine oil and the tester walks barefoot. The result is one of three classes:
- Class A: barefoot areas with limited water, such as dry changing rooms.
- Class B: showers and general bathroom areas.
- Class C: the highest barefoot grip, for pool surrounds, walk-in showers and steps into water.
This is the gap most often missed in pool and wet room specifications. A tile can arrive certified R11 and still be dangerous underfoot, because a pool is walked barefoot and barefoot grip is a different test. Note too that HSE warns floors classified Class A, and in many cases Class B, will still be slippery when wet, so do not treat a low barefoot class as a safe wet floor.
For pool interiors, steps and sloped entries, specify Class C to DIN 51097 rather than leaning on an R value, and ask the supplier for both the shod and barefoot certificates.
PTV results: the pendulum test and what the HSE uses
The Pendulum Test Value is the figure UK enforcement actually turns on. The pendulum is HSE’s preferred method for assessing floor slipperiness in both dry and contaminated conditions. A weighted arm fitted with a rubber slider swings across the floor and loses momentum in proportion to the grip, producing the PTV.
The classification HSE and the UK Slip Resistance Group use is straightforward:
- PTV 0 to 24: high slip potential.
- PTV 25 to 35: moderate slip potential.
- PTV 36 or above: low slip potential.
For most floors, aim for a wet PTV of 36 or above. Two sliders matter here. Slider 96 rubber is used for shod pedestrians, and Slider 55 rubber is used for barefoot areas. Quote the wrong slider on a report and the result is meaningless for that environment.
The pendulum has one decisive advantage over the ramp tests: it is portable. Ramp tests are laboratory only, so they grade a tile ex-factory but cannot tell you how the installed floor behaves once grout lines, falls, cleaning residue and wear come into play. The pendulum can be used in situ, in the same conditions pedestrians experience, and it is the test accepted in UK personal injury litigation. That is why an ex-factory R rating and a real-world PTV are not interchangeable.
Surface roughness as a supplement
HSE recognises a second on-site measure alongside the pendulum: surface microroughness, reported as the Rz value. For water-wet pedestrian areas, an Rz below 10 microns is high slip potential, 10 to 20 microns is moderate, and 20 microns or above is low. It is a quick handheld check that helps monitor wear over time, though HSE is clear it supplements the pendulum rather than replacing it.
Which UK standards apply
The testing sits under British and European standards, and the framework changed recently, so older specifications need checking.
- Pendulum testing: BS 7976-2 was withdrawn in February 2022 and superseded by BS EN 16165, with the same PTV results expected.
- Ramp testing: DIN 51130 and DIN 51097 were also superseded by BS EN 16165 in 2021, which contains no R or ABC categories, leaving specification down to each country.
Germany retained the R and ABC ratings through a national foreword, which is why datasheets still quote them. If you need an R or ABC rating on a UK job, reference DIN EN 16165 so the classification is unambiguous.
Underpinning all of this is duty of care. The Workplace (Health, Safety and Welfare) Regulations 1992 require floors to be suitable, in good condition and free from obstruction, and slip cases are assessed under this alongside the Health and Safety at Work etc. Act 1974. A documented PTV is the evidence that stands up when a floor is challenged.
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How to choose safer floor tiles
Choosing safer floor tiles is a matter of matching the rating to the real conditions of the space, not the best number on the box. A short specification routine keeps you compliant:
- Define the contamination and footwear: shod and oily points to R ratings and Slider 96 PTV; barefoot and wet points to ABC classes and Slider 55 PTV.
- Set a wet target, not a dry one: specify a wet PTV of 36 or above for shod pedestrian areas as the baseline.
- Do not rely on an R rating for barefoot areas: call up a DIN 51097 Class B or C for showers and pools.
- Ask for in-situ testing on large or high-risk floors: an ex-factory rating is a starting point, not proof the laid floor performs.
- Keep the certificates: test data forms part of your risk assessment and your defence if a claim lands.
Good practice on external and wet barefoot floors often runs slightly above the minimum. A common trade benchmark is a structured tile hitting a wet PTV of 40 or more on the relevant slider, which builds in a margin for tile-to-tile variation and cleaning wear as the floor ages.
One last habit worth keeping: slip resistance is maintained, not just installed. A high-rated tile that is polished by the wrong cleaning regime can drop below the safe threshold. Where you can, hand the client a note on suitable cleaning so the tile slip ratings you specified still mean something a year later.
Specify it right the first time
Tile slip ratings only protect you when they match the real use of the floor and are backed by the correct test. Before you order, confirm whether the area is shod or barefoot, set a wet PTV target of 36 or above, and get the certificates in writing. If a floor is high-risk or already down, arrange a UKAS-accredited in-situ pendulum test so the result stands up in a risk assessment. Specify from the standard, not the sales sheet, and the floor will pass when it counts.
