What the numbers mean, and the duties behind them.
The HSE classifies slip potential directly from the Pendulum Test Value. The thresholds aren't arbitrary — they were calibrated against real slip-accident data, and they are the same figures relied on in UKSRG guidance and in court.
| Pendulum Test Value (wet) | Slip potential |
|---|---|
| 0 – 24 | High |
| 25 – 35 | Moderate |
| 36 and above | Low |
The 36 benchmark
A floor reaching a wet PTV of 36 or more is generally treated as low slip risk — roughly a one in a million chance of a slip. Below 36 the risk climbs steeply and the surface needs further assessment; below 25 it is a known hazard. The scale is not linear, so small drops near the threshold matter.
Slopes and vulnerable users
Ramps, sloped access and areas used by the elderly or less mobile call for a higher target than 36, with the uplift increasing with gradient. We set the right target for each area when we report.
The legal backdrop
No law names the pendulum test, but the duty to assess and control slip risks is firmly in statute — the Health and Safety at Work etc. Act 1974, the Management of Health and Safety at Work Regulations 1999, and the Workplace (Health, Safety and Welfare) Regulations 1992, whose regulation 12 requires floors not to be slippery so as to put people at risk. A pendulum report is the standard way to show those duties have been met.