The method

How the pendulum test works

It’s the test the HSE recommends and the one that stands up in court. Here’s what it does, in plain English.

An artificial heel, at the moment of a slip

The pendulum — properly, the portable skid-resistance tester — was developed from road research and has been used on floors for decades. A weighted arm carries a rubber slider set at a fixed height and contact length. Released from horizontal, it swings down, the slider sweeps across the floor, and the arm carries on up the far side. The grippier the surface, the more the swing is held back. A trailing pointer records how far the arm rose, and that reading is the Pendulum Test Value (PTV).

The clever part is that it recreates the specific instant a slip begins: a heel landing and sliding forward on a contaminated surface. That’s why it correlates so well with real accidents, and why it’s trusted where other quick checks aren’t.

Always wet, usually dry too

Dry floors rarely cause slips; wet ones do. So the reading that matters most is the wet one. We flood the test area with clean water and take the floor at its realistic worst. We’ll usually record a dry figure as well for comparison, and where a specific contaminant is the issue — oil in a kitchen, soap in a wet room — we can reflect that too.

The right rubber for the job

Two standard rubber sliders are used, and choosing the correct one is part of getting a valid result:

• Slider 96 (Four S rubber) — simulates a shoe sole, for areas walked in footwear: shops, offices, kitchens, corridors.
• Slider 55 (TRL rubber) — for barefoot and heavily wetted areas: pool surrounds, changing rooms, wet rooms and bathrooms.

Using the wrong slider can make an unsafe floor look safe, which is one reason an accredited, experienced tester matters more than the kit alone.

Roughness, as a second opinion

For level floors that get wet, the microscopic roughness of the surface (measured in microns) closely tracks slip resistance. We can take surface-roughness readings alongside the pendulum as a cross-check, and to help diagnose why a floor is performing the way it is — useful when you’re deciding how to put a poor result right.

What a test day looks like

We arrive, agree the areas with you, calibrate the instrument on site, and test each surface wet (and dry where useful) with the correct slider. It’s quick, clean and undisruptive. A clear report follows within two to three working days.

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