Pendulum Accessories

It is important that the Pendulum Tester is carefully prepped before use. Failure to do so may result in inaccurate and unreliable readings.

In this tutorial, we explain how you use the Pendulum accessories to set up the instrument, condition the rubber sliders and verify your results.

What do I need?

  • A Rubber Slider
  • Aluminium Sample Holder
  • A complete set of conditioning and verification surfaces
  • Perspex Setting Gauge
  • Tools Wallet
  • Thermometer
  • Water Bottle

These are supplied in accordance with the UK Slip Resistance Group (UKSRG) guidelines. We recommend all users of the Pendulum obtain a copy of these useful instructions.

Further Information

If you would like further information about any of the Pendulum Tester accessories listed below, please get in touch via email ( or by phone (+44 (0) 20 8551 7000).

Rubber Sliders

Rubber Sliders are fitted onto the end of the Pendulum arm. There are three main types of slider. Each has specific properties and must be carefully selected depending on the type of surface that you are testing.

  • TRL(55) Rubber Sliders have a hardness of 55±5 IRHD. They should be used in ‘barefoot’ pedestrian areas (e.g. bathrooms, changing rooms, swimming pools). They are also used on vehicular surfaces such as roads and runways.
  • 4S(96) Rubber Sliders have a hardness of 96±2 IRHD. They should be in ‘shod’ pedestrian areas (indoor/outdoor public spaces, pavements etc.).
  • CEN Rubber Sliders have a hardness of 53-65 IRHD.

17 mm Spanner

Use the spanner to fasten the rear leg into position.

C-type Spanner

Once you have attached the Pendulum arm to the rotating head, tighten the retaining nut using the C Spanner.

Note: Ensure that the dowel is correctly engaged. Do not force it, as this may cause the hole to widen.

Aluminium Sample Holder

The Aluminium Sample Holder is used for conditioning the rubber sliders, verifying the Pendulum and holding floor/tile/road samples. It will prevent unwanted movement when testing samples and verification surfaces.

  • The clip is used for the P400 paper and lapping film.
  • The recess fits the Float Glass and Pavigres Tile.
  • The pegs allow you to adjust the size of the sample space when testing tiles and floor samples.

Perspex Setting Gauge

The Setting Gauge is to set the sliding length (or ‘footprint’) of the conditioned Rubber Slider. This is the distance the rubber slider travels whilst in contact with the test surface. The sliding length should be 124±1 mm (or 76 mm if using small rubber sliders). This should be measured from the trailing edge of the metal slider plate, not the rubber itself.

The outer marks on the Setting Gauge are 125 mm apart. The two marks on the left-hand side indicate the 2 mm tolerance allowed. The distance between the right-hand mark and the middle mark is 76 mm.

The Setting Gauge also has a working edge ruler. This helps to determine when the rubber slider is too thin to use.

Rubber Slider Conditioning Surfaces

The following equipment is required to prepare your rubber sliders before use:

  • Aluminium Sample Holder
  • Float Glass
  • P400 Conditioning Paper
  • Green Lapping Film (if using a TRL(55) Rubber Slider)
  • Pink Lapping Film (if using a 4S(96) Rubber Slider)
  • Water Spray Bottle

Preparation of the rubber sliders is crucial for good reproducibility of results. It will ensure that the rubber slider is in same condition at the start of each test. Rubber Sliders must always be clean and free from contamination. Failure to follow this procedure may affect the validity of your results.

Click here for instructions on how to condition rubber sliders.

Pendulum Verification Surfaces

The Pendulum Tester should be verified at the start of each day of testing and after re-assembly or transportation. The verification procedure is an extremely important part of the testing procedure. It demonstrates to you, and all those making use of your results, that the instrument has been set up correctly and is functioning properly.

Verification is achieved by performing tests on a number of well-defined surfaces with a known Pendulum Test Value (PTV). These are given in the table below:

TRL(55) Rubber Slider 4S(96) Rubber Slider
Pink Lapping Film N/A 59-64 PTV
Float Glass 5-10 PTV 5-10 PTV
Pavigrés Tile 13-19 PTV* 32-36 PTV

If these values are not achieved, you must not proceed with testing. Revisit the pendulum set-up procedure (including slider conditioning), and check the rubber slider for defects. If you continue to experience difficulties verifying your instrument, please contact Munro Instruments for further assistance.

* NOTE: Research by the UKSRG has found the TRL(55) Rubber Slider to be less consistent when used for pendulum verification. They advise verifying the pendulum using a 4S(96) Rubber Slider (even if the test itself is to be performed using a TRL(55) Rubber Slider). Research is ongoing.