The pendulum friction tester is the method endorsed by the UK Health and Safety Executive, recommended by the UK Slip Resistance Group, accepted by UK courts, and specified in the current European standard BS EN 16165.
UK pendulum slip testing sits within a framework of four interlocking documents. Understanding how they relate is the first step to reading a test report properly.
What about BS 7976? BS 7976-1 (specification), BS 7976-2 (method of operation) and BS 7976-3 (calibration) underpinned UK pendulum testing for two decades. They were withdrawn in February 2022 when BS EN 16165 was adopted. You will still see BS 7976 cited in older literature, historic test reports and pre-2022 legal material — the PTV values produced are materially equivalent to those produced under BS EN 16165, so legacy reports remain valid for comparison. Modern reports should reference BS EN 16165 Annex C.
The pendulum friction tester — originally developed by the Transport Research Laboratory for highway use — is a portable mechanical device that simulates the action of a pedestrian's heel striking the floor.
A weighted arm with a rubber slider at its tip is raised to a defined height and released. The slider sweeps through an arc and makes contact with the floor over a 126 mm test length. Friction between the slider and the surface slows the arm. A pointer records how far the arm continues to swing after the contact — the less it continues, the more friction, the higher the slip resistance.
The result is recorded as the Pendulum Test Value (PTV) — a whole number from 0 to 150.
Surface Performance Ltd — pendulum testing demonstration. Note: this video references BS 7976, which was superseded by BS EN 16165 in February 2022. The test method itself is unchanged.
BS EN 16165 actually defines four test methods (Annex A ramp with standard footwear, Annex B barefoot ramp, Annex C pendulum, Annex D tribometer). Results from different annexes cannot be directly compared — each answers a different question. In the UK, Annex C (the pendulum) is the method the regulators and courts work from, for three specific reasons:
Over 90% of slip accidents happen on wet floors. A dry-only test tells you almost nothing about the real risk. The pendulum is designed to be operated in both dry and water-contaminated conditions and is the only portable method that reliably replicates the heel-strike on a wet surface.
Ramp testing requires floor samples to be removed and taken to a laboratory. The pendulum is brought to the floor — which means it tests the installed surface, not a pristine factory sample. For live investigation of slip incidents, this is the only realistic option.
The HSE guidance document identifies the pendulum as the preferred method for both pre-installation assessment and post-incident investigation. The UKSRG — a body that counts HSE among its members and whose guidelines are relied on by UK courts in slip injury litigation — recommends the pendulum as the primary UK slip test.
PTV values map onto a simple risk classification for level pedestrian surfaces tested in the wet with a Slider 96 (Four-S) rubber:
The 36 threshold. A PTV of 36 or above in the wet is the HSE's accepted benchmark for a floor to be considered low slip risk. Below 36, the surface requires further risk assessment. Below 25, the surface is a known slip hazard regardless of appearance. UKSRG Guidelines Issue 6 introduces an explicit section on interpreting borderline results — the 36 boundary is a regulatory threshold, not a measurement cutoff, and should be applied alongside the test's measurement uncertainty.
The Pendulum Test Value scale was calibrated against real-world slip accident data. Research led by the HSE's Health and Safety Laboratory correlated measured PTVs with the slip accident rates observed on those surfaces. The boundary at which slip accident rates become acceptably low — for healthy adults walking on level surfaces — was established at PTV 36.
For surfaces with a slope, for access ramps, for wheelchair routes, and for areas used by the frail or elderly, a higher PTV is required. UKSRG Guidelines Issue 6 and HSE guidance specify adjusted thresholds based on gradient — approximately 1.75 PTV uplift for each degree of slope.
BS EN 16165 specifies two rubber sliders. The UK convention, supported by UKSRG Issue 6 and HSE guidance, continues to recognise:
BS EN 16165 as published references Slider 57 (a European compromise hardness) alongside Slider 96. In UK practice, Slider 55 continues to be used for barefoot scenarios — a position supported by HSE and UKSRG on grounds of continuity of data and slider availability. A comprehensive report identifies the slider used and applies the appropriate threshold.
A competent pendulum survey in accordance with BS EN 16165 Annex C and UKSRG Issue 6 includes:
The entire site visit typically takes 90 minutes to 4 hours depending on the number of locations.
A UKAS accredited BS EN 16165 report includes, at minimum:
EN 13036-4:2011 uses the same pendulum apparatus as BS EN 16165 but is specified for road and airfield pavement testing — the skid resistance of vehicular surfaces rather than the slip resistance of pedestrian surfaces. It tests wet only and in a single direction (aligned with traffic). The test is relevant to adopted highway surfacing, bus stop carriageway approaches, and vehicle-trafficked pedestrian crossings. On shared-use pedestrian/vehicle surfaces — zebra crossings, tactile paving, shared pedestrian/cycle zones — a pendulum report may cite both EN 16165 Annex C (pedestrian) and EN 13036-4 (vehicle) depending on the scope.
Visual appearance is a poor predictor of PTV. Many profiled safety floors test below 36 when wet. Many smooth-looking tiles test above 36. Without pendulum measurement, appearance is not evidence.
Manufacturer data is for new, clean, unworn product tested in laboratory conditions. Once a floor has been installed, walked on, cleaned with detergent, and exposed to contamination, the in-service PTV can be significantly different. The in-service value is the one that matters.
R ratings (R9 to R13) come from the German ramp test DIN 51130. They are widely quoted on tile manufacturer datasheets but are not used by UK courts, HSE or UKSRG as evidence of workplace slip resistance. There is no reliable correlation between R rating and PTV. A UK slip safety assessment needs PTV, not R rating. BS EN 16165 has replaced DIN 51130 in its scope.
Certain cleaning products — particularly those leaving surfactant residues — can cause PTV to drop sharply even on well-specified floors. Post-cleaning testing is a standard part of a proper survey.
UKAS ISO 17025 accredited pendulum testing across the UK. Report within 5 working days.