PTV Interpretation Guide

What PTV actually measures

The pendulum tester releases a weighted arm from a fixed height, swinging it through an arc. As the rubber slider on the arm strikes the floor, friction reduces the swing's onward travel. The reduction in residual swing is read off the calibrated scale as the PTV — a value that ranges from 0 (frictionless) to about 80 (very high friction).

The slider strikes the floor at a known velocity, simulating the heel-strike phase of a normal walking gait. The result is a measure of the dynamic coefficient of friction at that point.

The HSE bands

The UK Health and Safety Executive interprets PTV results using three bands derived from extensive forensic and laboratory work over four decades:

PTV (wet)	Slip potential	Probability of slip
0–24	High	Approximately 1 in 2
25–35	Moderate	Approximately 1 in 20
36+	Low	Approximately 1 in 1,000,000

The probability figures are approximate but illustrate why the 36 threshold is so widely adopted: above this value, slip risk is genuinely low; below 25, slip is essentially foreseeable.

Wet vs dry — what matters

For most UK environments where contamination is foreseeable (water, food, drink, cleaning fluids), the wet PTV is the relevant value. A floor that achieves PTV 60 dry but PTV 18 wet is a high-slip-potential floor in any environment that gets wet — which includes virtually all retail, hospitality, healthcare and public-realm settings.

Dry PTV is relevant only for environments where wet contamination is genuinely not foreseeable: dry warehouse aisles away from loading bays, internal office circulation away from entrances, dry archive storage areas. For these environments, dry PTV stands on its own. For everything else, wet is the binding constraint.

PTV vs SRV — the same thing

You will see both 'PTV' (Pendulum Test Value) and 'SRV' (Slip Resistance Value) in UK literature. They mean the same thing — the pendulum tester output. PTV is the more current term; SRV was used historically and still appears in some older specifications.

How specifications use PTV

Common specification references include:

• BS 8204 — typically PTV 36+ wet for in-situ floorings
• NHS specifications — typically PTV 36+ wet for circulation, higher for wet rooms
• Care home specifications — best practice PTV 40+ wet to reflect resident vulnerability
• Network Rail and TfL — site-specific PTV minima, generally 36+ wet
• Insurance schedules — sector-dependent; commonly 36+ wet, sometimes higher

PTV is a measurement, not a guarantee

A PTV of 38 wet does not guarantee that no one will slip on the floor. It means that the friction available at that test point, under the test conditions, places the surface in the low-slip-potential band per HSE guidance. In service, contamination, cleaning state and footwear interact with the surface in ways the standardised test cannot fully capture.

This is why pendulum data is best understood as one component of a broader slip-risk management framework — alongside cleaning regimes, signage, lighting, and incident-response protocols.