113 answers to the questions people actually ask — covering the pendulum test, PTV interpretation, UKAS accreditation, commercial practicalities, insurance, litigation, standards, and sector-specific applications.
The pendulum friction tester — specified in BS EN 16165 (Annex C), the European standard that superseded BS 7976 in February 2022 — is a portable device that simulates a pedestrian's heel striking the floor. A rubber slider swings through an arc and makes contact with the surface over a 126 mm sweep. Energy lost to friction produces the Pendulum Test Value (PTV). The test is performed in dry and wet conditions in accordance with UKSRG Guidelines Issue 6, and is the method accepted by the UK Health and Safety Executive.
The instrument was originally developed by the Transport Research Laboratory (TRL) for measuring highway surface slip resistance and has since been adopted for pedestrian-surface testing across the UK. The modern test methodology is governed by BS EN 16165 Annex C (pedestrian surfaces) and EN 13036-4 (road and airfield surfaces). UKSRG Guidelines Issue 6 is the corresponding UK practitioner guidance.
Dynamic coefficient of friction — specifically, the friction between a defined rubber slider and the test surface during a brief heel-strike event. The output is the Pendulum Test Value, a dimensionless number on a 0-150 scale.
BS EN 16165:2021 is the current European standard for determining the slip resistance of pedestrian surfaces. It replaced BS 7976 in February 2022 in the UK. Annex C of EN 16165 covers the pendulum test method; the other annexes cover ramp testing (Annex A shod, Annex B barefoot) and tribometer testing (Annex D). Modern UK pendulum reports reference BS EN 16165 Annex C as the test method.
BS 7976 (parts 1, 2 and 3, covering specification, method of operation and calibration of the pendulum tester) was the UK standard for pendulum slip testing for two decades. It was withdrawn in February 2022 when BS EN 16165 was adopted. PTV values produced under BS 7976 and BS EN 16165 are materially equivalent, so historic BS 7976 reports remain valid for comparison and in legacy legal material — but new reports should reference BS EN 16165 Annex C.
The UK Slip Resistance Group is a consensus body of slip testing specialists — including the HSE, testing laboratories, flooring manufacturers and materials scientists. It publishes the UK's definitive practitioner guidance on pendulum slip testing. UKSRG Guidelines Issue 6, published in January 2024 (with an April 2024 Table 3 amendment), is the current edition and is aligned with BS EN 16165. UKSRG guidelines are recognised by UK courts in slip injury litigation and are the document the HSE itself works from.
EN 13036-4:2011 is the European standard for measuring slip/skid resistance on road and airfield pavement surfaces using the same pendulum apparatus as BS EN 16165. It is the test method for vehicle-trafficked surfaces — tested wet only, in a single direction aligned with traffic. Relevant to adopted highway testing, bus stop carriageway approaches, and shared pedestrian/vehicle zones such as zebra crossings and cycle-friendly paving.
It measures dynamic friction, but the PTV is reported as a single whole number on the pendulum's own scale rather than as a coefficient of friction (μ). Other methods — including some US and European tests — report μ directly. The numbers are not interchangeable without conversion.
Individual test locations take around 10 minutes each. A typical site visit covering 10-15 locations lasts 90 minutes to 4 hours, including set-up, surveying, testing in dry and wet, photographing, and breakdown.
The apparatus is available to purchase, but a test performed by a non-accredited operator produces a non-accredited result. For any evidential use — insurance, litigation, HSE investigation, regulatory compliance — a UKAS accredited laboratory test is materially stronger than a self-performed result.
No. The test is entirely non-destructive. The rubber slider makes brief contact with the surface but leaves no mark, no indent, and no residue. A slip test can be performed in a trading retail store, an operational hospital ward or a live warehouse without any disruption to the floor.
No. The pendulum is a mechanical device operated by spring-loaded release. No electrical power is required. This makes it suitable for testing in plant rooms, car park decks, outdoor locations and other environments where power access may be limited.
The pendulum requires a reasonably flat contact area over the 126 mm test length. For very uneven surfaces — cobbles, setts with deep joints, heavily weathered paving — test placement is selected carefully and the results are interpreted with explicit reference to the surface variation.
For level pedestrian surfaces tested in the wet, a PTV of 36 or higher is the HSE's accepted benchmark for low slip risk. Below 36 the surface requires further risk assessment, and below 25 it is classified as high slip risk.
A wet PTV below 25 is classified as high slip potential by the HSE. Below 20, the floor is dangerously slippery when wet regardless of its appearance, cost or material.
HSE-commissioned research correlated measured PTVs with real-world slip accident rates. The slip accident rate drops sharply above PTV 36 and is relatively stable above that threshold — making 36 the lowest value at which the accident rate is considered acceptably low for general pedestrian use.
Up to a point. A PTV above 40 on a level surface indicates a very low-slip-risk floor. Extremely high PTVs (60+) can indicate a surface so textured that it becomes difficult to clean, uncomfortable for barefoot users, or aggressive on wheels and mobility aids. The design target is 'adequately high' rather than 'maximum possible'.
Dry PTV is measured with no surface contamination. Wet PTV is measured with applied potable water per BS EN 16165 Annex C. The wet result is the important one, because slip accidents happen almost exclusively in the wet. A floor with dry PTV 60 and wet PTV 22 is dangerous.
Surfaces are often more slip-resistant in one direction than another (ribbed rubber, brushed concrete, directional tile). The pendulum is tested in two perpendicular directions and the lower result — the controlling direction — is the governing value for risk assessment.
Statistically, no — the measurement uncertainty of a typical test is ±1-3 PTV. A result of 35 is technically within uncertainty of 36. However, the threshold is regulatory: a borderline result usually triggers additional testing or caveated interpretation rather than being treated as compliant by default.
The test itself is mechanical and doesn't require visibility, but test locations must be clearly identified and photographed. Testing in low-light environments (underground car parks, plant rooms, overnight retail testing) is routine and uses portable LED lighting.
Untreated or lightly sealed timber typically tests around 30-40 in the wet. Heavily sealed, polished or lacquered timber can drop below 25 when wet. Parquet and engineered timber vary widely with the seal condition.
New polished concrete can test anywhere from 25 to 45 in the wet depending on the polishing regime. Aggressive polishing to a high-gloss finish drops PTV; diamond-ground or textured polished concrete typically retains higher PTV. Wear from foot and vehicle traffic typically reduces PTV over 3-5 years.
Widely variable. Porcelain and ceramic tiles range from under 15 (polished porcelain) to over 50 (textured anti-slip). Manufacturer data and independent pendulum testing rarely agree perfectly — independent testing on the installed surface is the reliable measurement.
Good-quality safety vinyl with aggregate particles typically tests 36-50 new and remains stable for 5-10 years under standard cleaning. Decorative vinyl without aggregate can test well below 36 when wet, particularly after cleaning-product residue build-up.
A wheelchair access ramp, typically at 1 in 20 (2.86°), should achieve at least PTV 40 in the wet. Steeper gradients require higher values — 1 in 12 typically targets 45+ and 1 in 10 targets 50+. These are guideline targets; a full risk assessment may demand more.
The United Kingdom Accreditation Service is the sole national accreditation body recognised by the UK Government. It is appointed under the Accreditation Regulations 2009 to assess the competence of testing laboratories, calibration laboratories, certification bodies and inspection bodies.
The international standard for the competence of testing and calibration laboratories. It covers equipment, personnel, methods, data handling, reporting and quality management. UKAS accreditation to ISO 17025 is the technical competence mark for UK testing laboratories.
No. ISO 9001 is a quality management standard — it addresses how a company manages its processes generally. ISO 17025 is a technical competence standard specific to testing and calibration laboratories. A company can be ISO 9001 certified without any of its actual test results being accredited.
A UKAS accredited test means the equipment is calibrated and traceable, the test method is validated, and the technicians are competency-assessed — all independently audited. Without accreditation, a report is the operator's opinion. With it, the report has formally verified technical competence behind it.
Visit the UKAS public register at ukas.com and search for the company name or laboratory number. The entry will show the specific test methods covered. For slip testing, the method must explicitly include pendulum slip resistance testing — a general UKAS accreditation for unrelated methods does not cover slip tests.
A two-page PDF issued by UKAS to each accredited laboratory, listing the specific test methods the laboratory is accredited for and the locations from which those tests can be delivered. Every UKAS-accredited laboratory has this document and can produce it on request.
It can be introduced as evidence, but its evidential weight is materially lower than a UKAS-accredited report. An opposing expert can challenge the calibration, the method, the technician's competence, and the reporting format. A UKAS accredited report has all of these independently verified.
No test is guaranteed perfect. UKAS accreditation means the laboratory has demonstrated the technical competence to produce accurate results, including quantified measurement uncertainty. The result is the best estimate available, with its uncertainty explicitly reported.
For UK-based testing delivered to UK clients, UKAS is the appropriate accreditation body. Reciprocal arrangements exist internationally (ILAC) but for UK domestic purposes the direct UKAS accreditation is the standard.
Annually. UKAS carries out surveillance visits each year, with a full reassessment cycle every four years. Accreditation can be suspended or withdrawn if the laboratory fails to maintain the required standards.
Pricing depends on the location, number of test areas, and whether the site is trading during testing. A single-site survey of up to 10 test areas typically falls within a few hundred pounds plus expenses. Large estates, multi-site retail portfolios and expert witness work are priced on scope. We provide fixed-fee quotes within one working day.
Standard lead time from quote acceptance to site visit is 5-10 working days. For post-incident investigations or urgent commercial needs, same-week and next-day visits are available on request.
Standard reporting is five working days from the site visit to report issue. Rush reporting within 48 hours is available on request. Oral preliminary findings can be shared by phone on the day of testing if required.
No. Pendulum testing is discreet, non-destructive and low-footprint. A typical test location requires approximately 1 m² of clear floor for 10 minutes. We routinely test in trading retail stores, operational hospital wards, live warehouses and active office buildings without operational disruption.
Yes. Overnight, weekend and bank holiday testing is available. This is common for premium retail, busy hospitality venues, and critical infrastructure where daytime testing is not practical. Out-of-hours testing typically carries a premium.
Yes. Our technicians cover England, Scotland, Wales and Northern Ireland. Our laboratory is in West London but site visits are routine across the whole UK. Travel expenses are included in the quoted fee.
Yes, both Republic and Northern Ireland. For Republic of Ireland slip testing, we also operate a dedicated service site. Contact us directly for Irish work.
Yes. Client representatives are welcome to observe the testing, and the technician will walk through the methodology and explain each result on site. This is particularly useful for estates teams taking on slip-resistance responsibility for the first time.
Yes. Surface Performance Ltd carries full public liability, employer's liability and professional indemnity insurance appropriate to UKAS-accredited testing activity. Insurance certificates are available on request.
Yes. Mutual NDAs, client-specific contract forms, master services agreements and local authority procurement frameworks are all accommodated.
We work under a range of framework and contract-order arrangements with public and private clients. Specific framework enquiries are handled on application.
Yes. A UKAS accredited pendulum test report is admissible in civil and criminal proceedings in England, Wales, Scotland and Northern Ireland. The UKAS accreditation provides the technical competence foundation needed for the report to be treated as expert evidence.
Yes. We provide CPR Part 35-compliant expert witness reports and can give evidence in court where required. Expert witness work is priced on scope and involves specific engagement letter terms.
Civil Procedure Rules Part 35 governs the use of expert evidence in civil proceedings in England and Wales. A Part 35-compliant report follows a defined format and includes the expert's declaration that they understand their duty to the court. Our reports are produced to Part 35 requirements where engaged for that purpose.
Post-incident testing preserves evidence of the floor's as-found condition. Ideally the test is commissioned within 7 days of the incident, before cleaning regimes, surface treatments or environmental changes alter the floor. We routinely turn around post-incident surveys within the week.
Typically the party commissioning the test pays directly, and may recover costs through the claim process if successful. Insurers, defendant solicitors, claimant solicitors, and loss adjusters all commission testing. Payment terms are set out in the engagement.
Public and employers' liability insurers increasingly value documented PTV evidence when assessing slip risk. A proactive estate-wide UKAS accredited survey is a legitimate argument for premium reduction at renewal — though the extent varies by underwriter.
Some do explicitly; most expect it implicitly. A UKAS accredited report is the standard of evidence underwriters recognise. Non-accredited reports are accepted but are likely to be challenged at the claims stage.
No. Where we are instructed in a contentious matter, we maintain single-party engagement. We do not act for both claimant and defendant in the same claim.
A pass result against the HSE PTV threshold is a strong but not conclusive defence. Slip accidents can still occur on compliant floors due to specific contamination events, atypical footwear, or individual user factors. The pendulum report evidences the surface's inherent slip resistance; the full claim analysis considers broader circumstances.
The UKAS report states the measurement uncertainty explicitly. Borderline results (PTV 34-37) are typically treated with caveated interpretation. The uncertainty range is part of the evidence and can be explored in cross-examination.
Yes. Surfactant-rich cleaning products can leave a thin residual film that reduces PTV — sometimes by 10 points or more. Post-cleaning testing as part of a routine survey catches this effect; regular re-testing after a cleaning-product change is best practice.
Under-cleaning allows contamination build-up; over-cleaning can leave residue if the rinse step is inadequate. The PTV effect depends on the specific cleaning product and the application regime. Surveyed floors tested before and after cleaning give the clearest picture.
Some do, some don't. Genuine anti-slip surface treatments — chemical etch, shot-blast, applied aggregate coating — can measurably improve PTV. Some branded 'anti-slip' treatments are more marketing than measurement. Pre- and post-treatment UKAS pendulum testing evidences whether any given product actually improved the floor.
Depends on the treatment and the foot traffic. Chemical etch treatments on stone can last 3-5 years before re-treatment. Applied coatings last 3-10 years depending on wear. Post-treatment annual testing is the only reliable way to verify ongoing performance.
Yes — this is a routine application. A pre-treatment UKAS test establishes the baseline. A post-treatment test documents the change. The paired data supports any warranty claim against the treatment supplier and evidences the improvement for insurance purposes.
A new floor can improve slip resistance, but only if the replacement product is specified on slip resistance grounds — not aesthetics or price. We advise on specification, and post-installation pendulum acceptance testing confirms the installed floor delivers the specified PTV.
There's no single answer — the right product depends on the floor material, the soiling type, and the rinse regime. Manufacturer data from the floor supplier and the chemical supplier should identify compatible products. Where data is absent, supplier-specific pendulum testing before a product rollout is the safest route.
Typically yes. Polishing reduces surface texture at the micro-scale, and micro-texture is a key contributor to wet slip resistance. Polished stone, polished concrete and polished terrazzo routinely test below PTV 30 in the wet even when they look pristine.
Steam cleaning removes grease and build-up effectively, which generally improves wet PTV on surfaces where cleaning-residue films have formed. On sealed wood floors, aggressive steam can damage the seal and introduce new slip hazards. It's a net positive when correctly applied.
Yes. Any refurbishment that changes the floor — new tiles, new coating, new cleaning regime, new layout that changes foot traffic patterns — warrants a fresh UKAS pendulum test. The refurbishment-acceptance survey also provides the baseline for the next period.
Major supermarket chains typically commission slip testing as part of estate management, often on a 2-3 year rolling cycle per store. Specific areas — produce aisles, entrances, customer toilets — may be tested more frequently. Independent supermarkets and convenience stores test less regularly but increasingly do so as PL insurers push for evidence.
Commercial kitchen floors face simultaneous pressure from grease, water and frequent cleaning chemicals. A UKAS accredited pendulum test — including grease-contaminated testing — is the only way to quantify the real-world slip resistance. Post-refurb acceptance testing and periodic re-testing are both standard practice.
The same principles apply — the building size doesn't change the legal framework. A single-unit takeaway or cafe is an appropriate subject for a pendulum test, and the cost is typically modest relative to claim exposure. Many small-venue operators commission testing once every 3-5 years.
Yes. Schools combine high footfall, age-range diversity, and environments (sports halls, changing rooms, dining halls) that each have distinct slip profiles. Multi-Academy Trusts increasingly commission estate-wide surveys; local authority maintained schools vary.
Yes, alongside but separate from EN 1177 impact testing. Impact testing covers the critical fall height; slip testing covers pedestrian slip risk on the same surface. A complete playground safety audit addresses both, particularly for schools and local authority play provision.
Chain hotels increasingly mandate slip testing as part of brand-standard compliance. Independent hotels typically test in response to an incident, a refurbishment, or an insurer query. Guest bathrooms, lobbies and pool surrounds are specific high-priority test locations.
Warehouse slip claims are predominantly employer's liability matters and tend to settle at higher values than retail claims. A UKAS accredited baseline survey is a proportionate investment for any operation with pedestrian activity, particularly where painted walkways are present on the deck.
Care homes combine high fall rates, vulnerable users, and CQC regulatory scrutiny. A UKAS accredited survey supports CQC Regulation 12 compliance and is increasingly requested by operators, landlords and lenders as part of due-diligence packs.
Yes — external paving is subject to weather, algae, moss, leaves and freeze-thaw that indoor floors don't face. Seasonal re-testing (spring and autumn) captures the operational envelope. Local authorities testing adopted highways routinely include external paving in their Section 41 evidence.
Pool surrounds are a specific high-risk environment. Barefoot pendulum testing with the Slider 55 rubber — and ideally chlorinated-water contamination — is the appropriate protocol. PWTAG guidance treats measured PTV as a key element of pool-side safety.
Fitness environments present sweat-contaminated floors rather than water-contaminated floors, and the right testing protocol reflects that. Slip claims in commercial gyms are rising, and insurers increasingly expect UKAS accredited evidence for the estate.
Car parks concentrate pedestrian-vehicle interaction in a single environment and are a frequent claim location. Multi-storey decks, stair cores, painted pedestrian walkways and underground car parks all warrant pendulum testing. Operators increasingly commission estate-wide surveys.
Zebra crossing markings and tactile paving at signal-controlled crossings are specific pendulum targets. Highway authorities testing adopted public realm often include crossings as part of Section 41 evidence.
Yes. Shared mall flooring, food court areas, common toilets and landlord-managed entrance zones are all pendulum targets. The landlord/tenant liability split adds complexity, but a baseline landlord-commissioned survey of common parts is a clean starting point.
The Health and Safety at Work Act 1974 (sections 2 and 3), the Management of Health and Safety at Work Regulations 1999 (regulation 3 risk assessment), the Workplace (Health, Safety and Welfare) Regulations 1992 (regulation 12 floor condition), and the Occupiers' Liability Acts 1957 and 1984. All combine to impose duties on employers and occupiers regarding slip hazards.
Regulation 12 requires that floors are of a construction suitable for their use, kept free from obstructions and from any substance that may cause a person to slip or fall. In practice this is interpreted alongside BS EN 16165, UKSRG Guidelines Issue 6 and HSE guidance as requiring measured slip resistance evidence where slips are a realistic hazard.
Slip testing is not mandated by a specific statute, but in practice it is the evidential route used to demonstrate compliance with the slip-relevant duties under health and safety law. The Courts, the HSE and insurers all treat UKAS accredited pendulum data as the gold-standard evidence.
Section 41 imposes on highway authorities a duty to maintain the highway. Section 58 provides a statutory defence where the authority has taken such care as was reasonable. Documented pendulum testing, combined with regular inspection, is part of a strong Section 58 defence package for slip claims on adopted paving.
The Construction (Design and Management) Regulations 2015 govern construction activity. Slip testing of a new installation as part of construction handover is typically delivered under CDM, though the slip testing itself (being non-invasive and short-duration) is light on CDM administrative burden.
Approved Documents to the Building Regulations reference slip resistance in specific contexts (e.g. ramps in Part M accessibility). Actual pendulum test compliance is typically policed through BS 8204 for new floors and subsequent acceptance testing.
The CQC's fundamental standards under Regulation 12 require safe care — environment included. Pendulum-test evidence is not mandatory in so many words, but a falls-prevention policy backed by measured PTV data is materially stronger evidence under inspection than one without.
Ofsted's routine inspection regime does not specifically cover pendulum testing, but safeguarding inspections and Section 5 inspections include environmental safety. Multi-Academy Trust estate teams use pendulum evidence to support broader environmental risk files.
The HSE's own guidance treats UKAS accreditation as the benchmark for competent laboratory testing. It is not a statutory requirement in so many words, but in the HSE's interpretive framework, non-accredited tests are given less evidential weight in enforcement decisions.
Two UK acts (1957 and 1984) imposing duties on occupiers to ensure visitors (and in limited circumstances trespassers) are reasonably safe. Slip claims against premises occupiers are brought under this framework in civil litigation.
A UKAS accredited pendulum report includes: unique report reference and date, laboratory name and UKAS number, site and date of testing, description of each test location, photograph of each location with the pendulum in position, raw PTV results dry and wet in two directions, the mean and controlling-direction PTV, measurement uncertainty, HSE interpretation, and calibration identifiers for the equipment used.
PDF by email, typically within 5 working days. Hard copies are issued on request for some client types (legal proceedings, framework clients) at a supplementary fee.
The accredited content of the report follows UKAS-specified formats. Non-accredited commentary, customised executive summaries, and specific client-template covers can be added around the accredited core.
The laboratory retains full records (raw data, photographs, report copies) for a minimum of 6 years, consistent with the limitation period for civil claims in most UK jurisdictions. Longer retention is arranged by request.
A UKAS accredited report cannot be altered once issued. Supplementary reports, amended reports (for administrative corrections with version control), and re-issued copies for misplaced originals are all available on request.
Yes. Raw pendulum swing data, photographs, slider calibration records and other source documents are available to the commissioning client on request. In expert witness matters, these are routinely disclosed as part of the Part 35 process.
The accredited portion of the report does not include recommendations (UKAS rules require accredited results to stand alone). Non-accredited commentary, where requested, can include interpretive discussion and suggestions for risk management.
Reports are issued in English. For international applications, accredited English reports with accompanying translation are routinely accepted; formal accredited reports in other languages are not part of our standard output.
The laboratory retains all records and can re-issue copies on request, at nominal fee. Client reference numbers and/or original report dates are helpful for retrieval.
The report is the property of the commissioning client and disclosure is at their discretion. UKAS accreditation does not restrict onward sharing. Expert witness reports have specific privilege considerations governed by Part 35 and case-specific disclosure orders.
BS EN 16165 specifies two rubber sliders. In UK practice — supported by UKSRG Issue 6 and HSE guidance — Slider 96 (Four-S, Standard Simulated Shoe Sole) is the default for shod-foot pedestrian testing, and Slider 55 (TRL, Transport Research Laboratory) is the softer rubber used for barefoot testing such as swimming pools and shower rooms.
Each slider batch is conditioned and its hardness verified. Sliders are checked before use and retained for a defined number of tests before replacement. Sliders are traceable to their calibration record on the report.
Slider 96 is harder and represents a typical shod-foot rubber. Slider 55 is softer and represents a bare foot or a softer shoe compound. The two give different PTV results on the same surface — neither is more 'correct', they answer different questions.
Surface micro-roughness — expressed as Rz — is the peak-to-valley variation of the surface at a micro scale (typically microns). Higher roughness correlates with higher wet PTV on most surfaces, because the roughness breaks the continuous water film that causes slippage. Rz is a supplementary measurement to the pendulum, not a replacement.
The laboratory calculates measurement uncertainty through a validation process covering equipment uncertainty, operator repeatability, slider variability, and environmental factors. The combined uncertainty is reported alongside each PTV result.
Potable water per BS EN 16165 Annex C. In specific applications (pool surrounds with chlorinated water, kitchens with grease, highways with oil), supplementary contamination testing uses the real-world contaminant.
The pendulum is a portable case-mounted device. It travels in a dedicated vehicle with calibration records, slider stock and surface-cleaning supplies. Testing on upper floors, on stairs, and in awkward locations is routine.
Yes — and it is an operationally relevant condition. The apparatus is not harmed by rain, and a wet-weather test of an outdoor surface in realistic conditions is often more useful than a controlled wet test on a dry day.
Mildly. Very cold floors (cold stores, frozen paving) can show slightly different results because the slider rubber behaves differently at low temperatures. The calibration protocol accounts for operating temperature range, and extreme cold testing follows a supplementary protocol.
Dynamic friction is the friction between two surfaces in relative motion. Static friction is the friction resisting the start of motion. The pendulum measures dynamic friction — because the heel of a pedestrian slipping is in motion, not static.
No. Carpet is a compliant, non-continuous surface that doesn't fit the pendulum's measurement geometry. Carpet slip performance is addressed through different test methods and, in practice, through manufacturer data and installation specification.
Yes, with appropriate positioning. Stair nosings, step treads and landings are all routine pendulum targets. BS 5395 applies for the stair-specific context.
UKAS ISO 17025 accredited pendulum testing across the UK. Report within 5 working days.