Home / The tests
Method & accreditation
Two tests the HSE recognises
Slip resistance is invisible and changes over time. Two complementary methods measure it properly — and we’re accredited for both.
Pendulum — PTV
A calibrated slider reproduces a slipping heel. 36 or above is the recognised low-risk threshold.
Surface roughness — Rz
Used alongside the pendulum where floors get wet or greasy. We are accredited for both.
1 · Pendulum slip testing (PTV)
A weighted arm swings a calibrated rubber slider across the floor to reproduce a slipping heel, recording grip as a Pendulum Test Value. We test wet and dry, in three swing directions. 36 or above is the HSE’s low-risk threshold.
| PTV 0–24 | High risk |
| PTV 25–35 | Moderate |
| PTV 36 + | Low risk |
2 · Surface (micro) roughness (Rz)
A floor needs enough microscopic roughness to break through contaminants and grip footwear. Roughness testing tracks that, and works best alongside the pendulum — especially in kitchens, factories and other areas that get wet or greasy. Measured in microns; an Rz below 20 should be managed.
| Rz below 10 | High risk |
| Rz 10–20 | Moderate |
| Rz above 20 | Low risk |
The standards
- BS 7976-2 — operation of the pendulum tester.
- BS EN 16165 — the current standard for measuring surface slip resistance (it superseded BS EN 13036-4).
- UKSRG guidelines — how results are interpreted (we’re a UKSRG member).
Every duty holder must manage slip risk — employers, facilities managers, and in care settings in Wales, Care Inspectorate Wales (CIW), which expects it to be actively assessed and controlled.
Independent, and accredited
Surface Performance is entirely independent: no connection to any flooring manufacturer, treatment company or equipment maker, and no commission from anyone. UKAS-accredited (UKAS Testing Laboratory No. 7933, ISO/IEC 17025), and recognised by RoSPA, FIFA, World Rugby, the ITF and FIH for related work. Nothing influences the figure.
Laboratory product testing
Beyond on-site work, our environmentally controlled laboratory (to ISO 291) tests more than 300 flooring products a year — tiles, stone, resin, vinyl, decking and more — and can issue slip-resistance certification or support product development.
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Get your floors tested
Send the surface type, the rough area in square metres and where you are in Powys. A fixed, no-obligation quote comes back.