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Friction Is Pivotal To Testing For The Risk Of A Slip!

17th December 2013
According to RIDDOR (Reporting of Injuries, Diseases and Dangerous Occurrences Regulations), from 2011 to 2012, there was a total of over 30,000 slips and trips in the workplace ( including over 3-day injuries), accounting for an average of 40 per cent of all accidents and injuries to company employees.

Accident compensation solicitors continue to find that personal injury claims for slips, trips and falls are second only to motor vehicle accidents. The Health and Safety Executive (HSE) state that over 50 per cent of all reported employee major injuries involved a slip, trip or fall (from height), which has remained at a similar average for the previous five years.

When we take a closer look at accident claims for these categories of injuries, there can often be a slight but often crucial difference between a fall, which was caused by a ‘slip’, as opposed to a fall resulting from a ‘trip.’

An uneven or unstable surface caused by cracks, dents, a discarded or protruding object can cause a barely or partly noticeable obstruction leading to shoe toes becoming unexpectedly caught.

Arguably more dangerous is the hidden risk when walking across any flat surface including floors, stairs or walkways, and the imperceptible lack of friction to prevent the underside of a shoe or boot from slipping up. Under normal conditions, a vertically downward, a forward horizontal and a backward resistance force is exerted when walking across a flat surface.

If there is insufficient friction between the bottom of a shoe and the flat surface to resist the backward horizontal force a slip will occur if the friction is insufficient to resist the horizontal force. Popularly known as the ‘friction factor’, the amount of friction available to prevent slippage depends on a friction coefficient. By placing a shoe on a flat surface, and measuring the force necessary to make the shoe slip, then dividing this force by the weight of the shoe, the friction coefficient may be determined, which is the same coefficient as would be recorded when a full person’s weight is present.

The higher the value of friction coefficient, the less likelihood of slipping while the smaller the value, the greater the risk. Walking with conventional shoes on a concrete floor-surface will usually produce a coefficient high enough to reasonably assume a low probability of slipping. By contrast, linoleum generally produces a lower coefficient and could be low enough to be extremely hazardous especially when water is present.

The same evaluation can also be made with some types of stone, especially decorative tiles, which may give a coefficient that is low enough to be dangerous. Likewise with metal surfaces, especially when wet.

A rough estimate of the degree of slip resistance of a flat surface may be made by means of a ‘pivoting’ test, which simply requires placing all of the weight on the ball of one foot, and attempting to pivot on that same foot. Pivoting is likely to be more difficult or even impossible on a concrete surface, whereas pivoting may be found to be easier on a wet, linoleum floor.