It’s an extraordinary statistic but the Health and Safety Executive estimates that one serious slip accident occurs every three minutes in the UK.
There are many contributory factors to this type of accident – the presence of contamination, type of footwear and human factors (commonly it is elderly people who slip). However, in commercial projects there is an obligation for specifiers to ensure floor surfaces are suitable for their purpose under the Workplace (Health, Safety and Welfare) Regulations 1992.
The bad news for specifiers, especially when imported products are considered, is that there are several ways of measuring slip resistance that give differing results. Although slip resistance may be calculated, in practice the risk varies. For example, most flooring surfaces have lower slip potential when dry than when wet. Surface wear can also increase the danger.
The good news is that there is a preferred method to determine slip resistance: the BS 7976 pendulum test using UK Slip Resistance Group guidance. The higher the slip resistance value (SRV) the lower the risk. (Other terms used for SRV include: the pendulum test value and British pendulum number). A high risk of slip (that is, greater than one in five) has an SRV of between 0 and 24, while a low risk (less than one in a million) is classed between 36 and 64.
Most level floor surfaces, when dry and clean, have satisfactory slip resistance, with SRVs in excess of 50. It’s an altogether different story in wet conditions. For example vinyl, linoleum and rubber have low SRVs when wet. Even “safety” vinyls may only have moderate slip resistance. Ultimately the specifier needs specific data for individual products.
Floor coverings that claim slip resistant properties are manufactured from materials that provide rough surfaces, but remember to check the basis of declared slip resistance values, in particular whether they apply to wet or dry conditions.
Softer floor coverings tend to wear more quickly than hard surfaces, resulting in shorter lives, while the slip resistance of vinyl can be enhanced by incorporating abrasive material grits (BS EN 13845).
Synthetic resin thin finishes are typically based on epoxy, but also include polyurethane and acrylics. Thicknesses vary from 150 microns to 6mm, and angular aggregate or carborundum particles can be applied, but these rough superficial layers wear off in time.
It is also worth remembering that the method of grouting ceramic tiles can reduce slip resistance, particularly flood grouting.
Design and whole life costs
Slip resistance varies with use and wear. Unfortunately, it is not always possible to predict changes and it needs to be measured over time to inform the maintenance and replacement regime.
With the compensation culture in the UK on the rise, preventing slips, trips or falls is a less costly strategy than hoping they will not happen. To do this, the correct specification of flooring and suitable maintenance are essential.
Numerous organisations provide information on safety floors: the Health and Safety Executive, the Centre for Accessible Environments, BRE, Resin Flooring Association, Contract Flooring Association and CIRIA publication C652, 2006, Safer Surfaces To Walk On.
Specifier 25 January 2008
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