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What is an R rating?

The R-rating that is so commonly used can be thought of as a ramp-rating, it is a slip rating given to a floor surface depending on how well it performs on the Oil-Wet Ramp Test.

The oil wet ramp test is conducted as follows. The sample to be tested is placed on a platform capable of being inclined from 0-45o, the sample is then covered in engine oil. One of the two operators with specific shoes then is harnessed in to the platform and the shoes brushed with the oil. The operator then walks up and down the platform slowly inclining it until the point at which a slip occurs, this is then repeated another two times, and then repeated by the other operator.

From the angle at which the operators slip, we can allocate an R slip rating.

What is it used for / where does it apply?

Since with R-ratings the contaminant that causes slips to occur is oil, they are more appropriate to areas where it is logical that oil will be present on the surface, this includes commercial kitchens, areas with automobiles and some industrial areas. The Oil-Wet Ramp slip test method is also limited to laboratory testing.

What are the alternative slip ratings?

If the surface isn’t likely to be contaminated with oil, then another slip resistance test might be more appropriate for your needs.

If the surface is likely to get wet with water then a Wet Pendulum Slip Test (P-rating) is most appropriate as it tests the surface when wet with water. There is also the Wet-Barefoot Ramp test which is similar to the Oil-Wet Ramp test but uses a constant flow of water over the surface and barefoot operators in order to achieve first an angle of slip and then a corresponding slip rating.

If the surface is unlikely to get wet then a Dry Floor Friction Test (DFFT) is most appropriate, as it gives a result for dry slip resistance. This test is commonly coupled with the Wet Pendulum test as spilt drinks and rain shed from clothing and umbrellas can cause an internal dry area to become wet.

Both the Wet Pendulum and DFFT testing methods are portable and therefore can test existing floor surfaces for slip resistance.

Is there a correlation between the slip ratings?

Unfortunately there is no set correlation between the results of any of the four slip testing methods mentioned above; so deciding which method is best for the area of concern is crucial.

For more information on which test method is best for you, contact the Slip Check team based in either Sydney or Melbourne.

Author: Ryan Voorderhake

Ryan Voorderhake


Ryan Voorderhake is a tertiary qualified slip resistance testing consultant with Safe Environments having a completed a Bachelor of Forensic Science (Honours) in Applied Chemistry at the University of Technology, Sydney. Ryan is proficient having undergone successful completion of Safe Environments NATA endorsed training program in wet pendulum testing, dry floor friction testing, oil wet ramp testing and pendulum calibrations to the Australian Standards AS 4586 & AS 4663. With a size 13 boot, Ryan is the giant of floor slip testing when undertaking the oil wet ramp test.

Ryan is proficient in conducting luminance reflectance testing to determine compliance with luminance contrast testing. Luminance contrast testing is a useful aid to assist visually impaired persons in wayfinding.

As well as a qualified floor slip tester, Ryan utilises his forensics degree in conducting asbestos analysis and materials testing duties for ceramic and stone tiling systems.