Wet Pendulum Test
The principle of the Wet Pendulum Tester to assess the friction characteristics of each specimen is by determining the wet dynamic friction between the specimen and the slider of a pendulum swinging in a vertical plane.
Portable instrument is used in the laboratory for classifying the wet slip resistance of new flooring (pedestrian surfaces) materials. It is also used on site to assess the slip resistance of existing floors and pavings.
A rubber slider is attached to a spring loaded foot at the end of a pendulum arm (leg). The pendulum arm is released, allowing it to swing so that the slider contacts the wet pedestrian surface over a set distance of 126mm. The slider rubber surface of the device has to be conditioned prior to each testing. This is done using a grade P400 abrasive paper.
The extent to which the pendulum fails to reach its release height on the overswing is used as a measurement of the slip resistance.
There are two types of slider materials in use; the Four S rubber (Simulated Standard Shoe Sole) and TRL (Transport Research Laboratory) rubber. Of the two, The Four S rubber is the one most commonly used.
Once the device is ready for testing, the surface is tested according to the relevant standard specifications. The results are recorded and a slip resistance test certificate is issued.
The table below will interpret the results and the certificate will nominate the corresponding classification as well.
|INTERPRETATION OF WET PENDULUM RESULTS|
(Reproduced from AS/NZS 4586)
|Contribution of the floor surface|
to the risk of slipping when wet
|1. While either of these test methods may be used, the test report shall specify which slider was used.|
Sources: CSIRO / Global Safe / Attar
Image Source: Safe Environment
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