Wet pendulum slip testing on site, to AS 4663:2013
The pendulum is the reference method for measuring how much grip a wet floor gives a shoe. We bring it to your site, test the floor you actually walk on, and report a P rating for every location, with the reasoning behind it.
What the pendulum measures
The wet pendulum tester is a weighted arm with a rubber slider on the end. The arm is released from horizontal, the slider skims across a wetted patch of floor for a set contact length, and a pointer records how far the arm continues to swing. The more friction the floor offers, the more energy the slider loses and the shorter the follow-through. That reading is the British Pendulum Number, or BPN.
AS 4663:2013 sets out how to do this on a floor that is already installed: how to prepare the surface, how many swings to take, how to wet the test spot and how to average the readings. The mean BPN is then placed in one of six classes, P0 to P5, using the same class boundaries that AS 4586:2013 uses for new products. HB 198:2014 recommends which class each kind of location should reach.
Why wet, not dry
Almost every serious slip on a hard floor happens when a contaminant gets between the shoe and the surface. Water is the most common, which is why the standard method tests wet. A dry reading on a polished lobby can look excellent while the same floor is hazardous in the first minutes of rain. Testing wet reflects the moment of failure.
What affects the result
The number is a property of the surface as it is on the day, not of the tile in the catalogue. Wear, polish, sealer build-up, detergent film and grout height all change it. Two identical tiles in the same building can return different classes because one is in a walk line and one is under a bench. That is why we test the locations that matter rather than a token sample, and why we record the surface condition alongside each reading.
- Surface cleaned of loose debris and wetted to the standard
- Five swings recorded and averaged after conditioning swings
- Slider type selected for footwear or barefoot use and stated in the report
- Surface type, finish and visible contamination noted
- Photograph of the test spot with a location reference
- Mean BPN, P class and HB 198:2014 comparison for the location type
Where the pendulum is the right tool
Entrances and foyers, ramps and stairs, pool surrounds and change rooms, kitchens and bathrooms, external paths and loading areas, and any internal floor that is wet-mopped or exposed to spills in use. For floors that stay dry, see the dry floor friction test.
How a pendulum test is run on your floor
Verify the instrument
The tester is levelled, zeroed and checked for free swing, and the slider is inspected and conditioned before the first location.
Prepare the spot
Loose grit is removed, the slider path length is set, and the surface is wetted with clean water immediately before each swing.
Swing and record
Conditioning swings are followed by five recorded swings. Readings are averaged to give the mean BPN for the location.
Classify and interpret
The mean BPN is placed in its P class and compared with the HB 198:2014 recommendation for that location type, then written up with a priority.
From BPN to P rating
The class boundaries are fixed. What varies is the target: a covered dry entry might only need P2 while an external ramp needs P5. The report always states which target applied.
| Mean BPN, Slider 96 | Class |
|---|---|
| > 54 | P5 |
| 45 to 54 | P4 |
| 35 to 44 | P3 |
| 25 to 34 | P2 |
| 12 to 24 | P1 |
| < 12 | P0 |
Wet pendulum testing questions
Is the wet pendulum test destructive?
No. The slider brushes across the surface for a fraction of a second and leaves nothing behind but a small wet patch. Testing can happen on a floor that is in use once the area is cordoned off.
How long does each test location take?
Allow around fifteen to twenty minutes per location once set up. A typical site of five to eight areas is finished within a half day, including photographs and notes.
Do you need the floor closed?
Only the immediate test spot, roughly a metre square, needs to be clear while the pendulum is in use. We work around trading, residents and shifts and can test after hours where that suits better.
What is the difference between Slider 96 and Slider 55?
Slider 96 is the standard rubber used for pedestrian footwear conditions and is what P ratings are based on. Slider 55 is a softer rubber used for barefoot areas such as pool decks and change rooms. We select the slider to suit the location and state which one was used in the report.
Pendulum testing across your sites
One supplier for Melbourne, Sydney and Brisbane, and a Premrest business, so a failed floor comes with a rectification quote. Single site? Price it online.