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Injuries from slips, trips and falls are prevalent in workplaces and public spaces across the UK. Health and Safety Executive (HSE) data indicates that in 2022-23, 32% of reported non-fatal workplace injuries were from a slip, trip or fall. The resulting cost to employers is estimated at over £500 million a year, while the cost to society is over £800 million per year.
Research by the charity, Living Streets, found the cost to local authorities in England for personal injury claims from slips, trips and falls in outdoor spaces was around £15.6 million in 2018, reducing to around £7.3 million in 2020. These figures were dwarfed by resulting medical costs and ongoing social care.
Several factors can cause or contribute to a slip, trip or fall, including:
- Physical properties of flooring surfaces and footwear.
- Area design, including slope of floors, presence of steps, lighting levels and distractions.
- Presence of surface contaminants.
- Housekeeping and cleaning regimes.
- Human/behavioural factors.
It is important to consider all these factors when assessing the risk or investigating the cause of an incident. One element organisations can control is the slip resistance of flooring material.
Slip resistance
Slip resistance is a measure of the friction afforded by a surface to prevent sliding of a shoe or foot. There is a direct relationship between slip resistance and the likelihood of slipping.
Most surfaces offer reasonable levels of slip resistance when clean and dry; but this can reduce considerably when contaminated.
Contamination sources include:
- Rainwater carry over to internal floors due to inadequate provision of matting at entrances.
- Liquid spills.
- Manufacturing or food processing materials (such as liquids and dry dusts) reaching floors in working areas.
The slip resistance in liquid contaminated conditions is related to the roughness and profile of the surface. Wear during the life of a floor surface can reduce its microroughness due to polishing, decreasing its slip resistance.
Ineffective cleaning regimes can also lead to an effective reduction in the surface microroughness.
The Pendulum Test
The primary method for assessing slip resistance recommended by the HSE and the UK Slip Resistance Group (UKSRG) is the pendulum test, complimented by surface microroughness measurements.
The pendulum tester is a portable calibrated test instrument that simulates the interaction between a pedestrian’s heel and the ground. It provides a standardised measure of the dynamic coefficient of friction on a numerical scale – the pendulum test value (PTV). Correlation with real world slip incident data shows that as the PTV increases, the likelihood of a slip occurring decreases.
It is recommended that the pendulum tester is used by trained operators in accordance with the relevant standards to ensure reliable data is obtained.
Roughness Tester
A roughness tester is a handheld device that can measure the total surface microroughness (Rz) of floor surfaces. Although this does not provide a measure of the dynamic coefficient of friction, it has been found to provide a good indication of the slip potential in wet conditions.
Roughness testers can be used with minimal training, for example by building owners, making them suitable for regular routine monitoring of floor surface wear to compliment pendulum testing.
UK legislation places legal obligations on employers and building owners to ensure floors are suitable for their intended use, but specific minimum PTV and surface microroughness requirements are not specified in legislation.
The UKSRG and HSE have published recommended minimum PTV and surface microroughness levels that are considered to provide an acceptably low risk of slipping. The recommended PTVs are based on research carried out by the Building Research Station (now the Building Research Establishment) in the 1960’s involving able bodied, working-age individuals walking in a straight line on a level surface.
It should be recognised that the slip resistance demands for a particular surface will be heavily dependent on how the area is used, and by whom. For example, Network Rail and the Department for Transport recommend slightly higher PTVs for train station flooring, which is liable to be exposed to rainwater contamination and used by people rushing.
Nevertheless, the UKSRG and HSE guideline values can be considered to provide:
- Methods for testing and of slip resistance.
- Widely recognised minimum recommended requirements for new and existing floors.
- Points for consideration for post-incident assessments.
Proactive management of floors can minimise slip risks by:
- Specifying floor surfaces for the environments and contaminants they are likely to be exposed to during service.
- Inspecting and testing regularly, especially in high traffic areas (pendulum testing is recommended at least annually by the UKSRG)
- Developing effective cleaning regimes.
- Maintaining good housekeeping, for example, prompt cleaning of spills.
- Providing staff training.
Regular testing can help to identify potential hazard areas before an incident occurs, allowing for timely remedial action through cleaning, treatment or surface replacement.
Proactive management can demonstrate due diligence in the event of an incident and resulting personal injury claim. In such an event, prompt post-incident pendulum testing of floor surfaces is recommended to provide accurate data for investigating the likely cause.
However, it cannot be overstated that the measured slip resistance of a floor surface is only one of several factors that may contribute to a slip, trip or fall incident, and a holistic approach to investigations is required.
Effective floor surface management can:
- Create safer environments for employees and the public.
- Mitigate potential personal injury claims.
- Reduce costs associated with slip, trip and fall incidents.
- Demonstrate an organisation’s commitment to safety.
