The BPN rating is an important measure of a surface's slip resistance

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A BPN rating stands for British Pendulum Number and is an important measure of how your flooring will perform under wet conditions.

What is a BPN rating?

If you are considering installing any floor surface, it’s crucial you take note of the product’s slip rating. This is particularly important for smooth floors such as polished granite and those installed in wet areas like a bathroom or poolside.

A BPN rating is an individual measurement which is determined during the slip testing of a floor surface. The Australian Standard for slip resistance is AS 4586 and includes several tests to rate the performance of a surface.

Here we take a look at the BPN rating and some of the slip testing methods used to meet the Australian standards.

Wet slip resistance measurement

The wet pendulum test is the most versatile slip test for surfaces that are prone to getting wet. This method uses a friction tester that measures the resistance between the surface and a rubber slider that is fixed on the end of the pendulum arm. It exerts a prescribed force over the stone as it slides across the wetted surface. The individual measurement is expressed as the BPN (British Pendulum Number).

The slip rating is based on a minimum of five sites tested to create a relatively consistent reading where the average of the BPN is used. This is converted into a pendulum classification from P5 to P0. The average of these five measurements is then defined as the product’s Slip Resistance Value (SRV).

A P5 classification with an SRV rating above 54 suggests there is a very low risk of slipping. P0 with an SRV of less than 12, on the other hand, suggests there is a very high risk of slipping.

The pendulum classification helps inform the suitability of materials in particular locations. Here is an example:

  • P5 – commercial kitchens, swimming pool stairs, steep external ramps and loading docks.
  • P4 – communal shower areas, serving areas of bars, external walkways, driveways, balconies and pool surrounds
  • P3 – public toilets, hospital bathrooms, wet entries to public buildings, shopping centre food courts.
  • P2 – hotel kitchens, hospital wards and corridors, hotel bathrooms, transitional entry areas to public buildings
  • P1 – supermarket aisles, dry entry areas of public buildings
  • P0 – surfaces that shouldn’t be contaminated with water and should be kept dry for safety.

Dry slip resistance measurement

The dry slip resistance of a surface is measured using the Dry Floor Friction Test (FFT). It is performed on products that are intended for internal use that are not located in wet environments such as lobbies, foyers or living spaces.

Using a floor friction device it measures the dynamic Coefficient of Friction between the flooring surface and a rubber slider as it moves across the floor. A Coefficient of Friction greater than or equal to 0.4 is classified as ‘D1’. A result of less than 0.4 is classified as ‘D0’.

Wet Barefoot measurement

A Wet Barefoot test is commonly used to test the slip resistance of surfaces used in communal change rooms or around swimming pools.

It is performed by a person who’s bare feet have been soaked in water prior to them working forwards and backwards over the sample surface. During the test, water is poured over the surface at a continuous rate and there is an increase in inclination to assess the safe limit of walking in bare feet.

The results of this test are classified as slip ratings A, B & C with the overall mean angle calculated. A barefoot slip resistance of ‘A’ with a mean angle of greater than or equal to 12°, for example, may be used in changing room applications. An example location of a product in category ‘C’ with a mean angle of greater than or equal to 24° would be sloping pool edges.

Oil-wet Ramp test

The Oil-wet Ramp test is an alternative to the Wet Barefoot test and is performed in a similar way but oil is used rather than water and testers are wearing safety boots. After the rating as expressed as an ‘R’ classifications ranging from 9-13 with R10 the most common slip rating specified.

R9 is rated alongside a ramp angle of greater than or equal to 6° but less than 10°. R13 is equal to or greater than 35°.


Understanding the BPN rating and the floorings ability to perform under wet conditions will help ensure you’re choosing the most suitable surface for your individual application.

You’ll find testing data information for our stone range amongst the product resources on our website.