We've all seen the small yellow signs denoting a surface that is slippery when wet. I suspect a few may have gone on to wonder how exposing staff, visitors and customers to a known hazard with simply a warning to be careful has become so widely accepted and in some cases, even permanent. Some signs even advertise the fact the surface is dangerously slippery, which would be laughable were it not so serious. I can't imagine exposed electrical wires 'protected' by similar means could ever become acceptable, yet the sign serves the same purpose, advertising the fact that a known hazard exists because it has not been effectively managed, and asking those at risk to do their best to avoid injury.
Those displaying the offending signs will sometimes claim that the signs themselves negate slip risk, that slippery wet floors cannot be avoided, or the blame will be directed to the staff responsible for keeping the area dry. Whilst those responsible for cleaning may occasionally be at fault, often the real problem has arisen simply because a risk assessment specifically aimed at slips has never even been considered, or has been undertaken in the briefest manner as part of a risk assessment of far wider scope.
Those responsible for the safety of their staff, visitors or members of the public can be left in the unfortunate situation of having a slip risk which is impossible to practically manage or, perhaps worse, complete ignorance that the slip risk exists. As a result of the convoluted information available to flooring specifiers (discussed in another article), surfaces are commonly assumed to be dry in end use, when in reality maintaining those surfaces in a dry condition reliably is impossible. Because these surfaces have been assumed to be dry in end use they were not designed to offer safe levels of grip in the wet. Less than competent slip risk assessment can result in these areas being effectively signed off as safe because less obvious sources of contamination which would serve to make the surface dangerous have not been considered.
It is important to note that responsible parties are not required to demonstrate all floors achieve a >36PTV (low slip risk) in all conditions, though those managing to comply with this will certainly find themselves on the right side of the law. The Health and Safety at Work etc Act 1974, Management of Health and Safety at Work Regulations 1999 and Workplace Health Safety and Welfare Regulations 1992 all broadly state that floors must be risk assessed and all reasonably practicable measures taken to control slips. Whilst some could argue the law is vague, others may argue it permits the application of some common sense. My own experience in conducting accident investigations for solicitors suggests that a value of >36PTV, achieved in the conditions of the accident, is sufficient to successfully dismiss a compensation claim in almost every instance. Conversely, a <36PTV recorded in the conditions of the accident almost always means a successful claim. It is crucial to ensure that safe grip levels are present in the conditions of end use, whatever those conditions may be.
What may be open to interpretation is what could be considered 'reasonably practicable' in terms of managing slip risk. It would be reasonable to assume all clean and dry surfaces offer safe levels of grip, the HSE themselves state, "If floors are clean and dry they should present a low slip potential". In my own extensive experience I have tested only two surfaces which have presented a slip hazard in the dry, both of which were of unorthodox plastic construction. The attention falls then, to surfaces which may be subject to contamination in end use. The most common contaminant in most environments being water based.
Understanding what constitutes a wet floor is a good starting point that isn't as obvious as it might sound. Slip resistance is lower in wet conditions because the fluid forms a barrier between the heel and floor, effectively reducing contact and resultant friction. Technically, the amount of fluid required to generate a hydrodynamic squeeze film and cause hydraulic uplift is dependent on the microscopic roughness of the floor surface. In practical terms, the roughness parameters of the floor surface that affect wet slip resistance are measured in microns (a millionth of a meter), and only the tiniest amount of water, such as that left behind several minutes after mopping, is required to make a surface wet. Once sufficient fluid is present to cause the formation of a squeeze film, additional fluid will have no real impact. In this sense a coffee spill, or drops from a wet jacket, are likely to be as slippery as an inch deep puddle.
Once it is understood just how little water is required to make a floor wet, the challenge in identifying and controlling potential contamination sources becomes apparent. Many slip accidents occur because a surface which is known to be safe in the dry has become wet and slippery. Those conducting slip risk assessments should consider starting with any reported hot spots and those areas most likely to suffer from contamination. Kitchens, canteens, entrances, WC's and external walkways tend to be higher risk areas where contamination controls are impractical. Consideration should be given to less obvious contamination sources, drinks may be spilled unknowingly, negating a clean as you go policy, water may drip from wet clothing, even if shoe soles are dried by entrance matting, condensation may form on or adjacent to poorly insulated surfaces and certain appliances may be known to staff to leak regularly. Cleaning regimes are too often ignored as a source of contamination of the surface. Even areas 'dry mopped' often leave fluid on the surface and may pose a serious slip risk unless effectively cordoned off.
For the layperson erring on the side of caution it would be reasonable to assume that clean and dry floors offered safe grip levels and wet floors were slippery. Wet surfaces do not always pose a hazard of course, many products offer safe levels of grip in wet conditions, but if surfaces can be reliably maintained in a clean and dry condition in end use you are unlikely to have an issue. For those surfaces where contamination sources have been identified, and control measures cannot be reliably implemented, it would be prudent to conduct a slip test using the HSE preferred BS 7976 Pendulum, to determine whether a real slip risk exists. Responsible parties should be wary of committing to a risk assessment that suggests an area can be maintained in a dry condition if the reality is that such controls are unreliable or impractical. A risk assessment stating the area is to be kept dry, being produced after a slip accident occurring in the wet, is unlikely to do much to support the defence of a claim.
Whilst it is possible to argue the margins of what can be considered reasonably practicable, and whether a surface was wet so infrequently as to pose a negligible risk, such arguments will generally occur after someone has been injured and at the hourly rate of legal teams. The costs of such arguments may exceed the cost of preventing the hazard altogether. It is relatively straightforward to avoid being in this situation simply by;
Of course if the slip resistance of a surface gives cause for concern, regardless of conditions, a competent and impartial slip risk assessment will likely prove a wise investment. It should also be considered that this article focuses on the common scenario of a wet floor, rather than the particular challenges posed by heavier contaminants.
The costs associated with just a single accident eclipse those associated with a thorough test remit covering multiple surfaces. Even for those surfaces which may fail to offer safe levels of grip in the wet, improvements can often be made through changes in cleaning regime alone, or through effective and convenient anti-slip treatments, before wholesale replacement of the surface should be considered. The costs associated with a slip compensation claim may offer some guidance in determining the limits of reasonably practicable cost in remedying the hazard, and these would cover the worst case wholesale replacement of the surface in most instances. The first step to preventing an accident and compensation claim remains free however, taking slip risk assessment seriously, and I hope that this article has helped in that regard.