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UK Specialists in H&S Approved Floor Pendulum Testing for Businesses and Expert Witness Services for Slip Injury Lawyers
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Tribology (Origin: from Greek tribos meaning ‘rubbing’) is the scientific term for the study of interacting surfaces in relative motion including floors. It includes the study of the principles of friction, lubrication and wear. Read more at
A measure of how much resistance there is between two surfaces either at rest (static) or moving (dynamic) when the surfaces are in relative motion is the CoF (Coefficient of Friction). The Pendulum Test measures dynamic CoF as this is regarded as measuring the action of the heel passing across the floor. The higher the CoF (Or Pendulum Test Value), the higher the slip resistance; the Pendulum Test Equipment measures CoF but multiplies the value found by 100 so it can be easily read on the scale giving you the Pendulum Test Value or Slip Resistance Value (PTV or SRV); note – zero is the worst state.
Most car drivers will have at some time in their lives experienced ‘hydroplaning’, where the tread of the tyre cannot displace rain water effectively enough and a slip occurs; particularly relevant when the tyre or the road or both are worn. The hydrodynamic process researched by the HSL identifies that the action of a heel on a floor works in exactly the same way. The smoother the floor / the smoother the heel, the more likely a slip will occur; the HSE has identified 90% of slips occur on a smooth wet floor.
The Surface Roughness Test Equipment (example supplied by Taylor Hobson) only checks for the roughness of the surface and works the same wet or dry; this is because its prime method of use is to drag a diamond stylus across the floor and the diamond cuts through anything including greasy contaminants
Slips occur when, in most cases, the heel is prevented in making an effective contact with the floor. This is because there is a contaminant which cannot be compressed into the pores or the grooves of the surface (or shoe heel if the heel edge is contoured which is unlikely, particularly in old worn shoes). As a result the contaminant (wet – for example rain water; or dry – example flour or talcum) will act at a microscopic level like little hard round balls; similar to a cartoon character stepping on marbles.
Floor Contaminant Viscosity
The HSL has also identified the higher the viscosity (thickness of liquid) then the more likely that slip will occur and diluting (with water for example if clearing away a spill) will actually held reduce the problem to a lesser degree.
Floor contaminants are not just liquids; there are also dry contaminants as well. In fact, a medium like Talcum powder (Dry contaminant) used as a floor testing medium will seriously reduce the ability to prevent slips as much if not more than pure oil. Wet contaminants can, as examples only, range from blood, coffee, urine, oil, grease and diesel and dry contaminants might include talcum, flour, saw dust, sand, plastic granules, shot blast pellets etc. What is important to understand about contaminants is that you must consider the contaminants either in the area or likely to be walked in / fall onto any floor area you are testing.
There are literally hundreds of different shoe type compounds and floor types and it would be impossible to create a test regime to cover even a fraction of them; particularly as you would have to consider the amounts of wear, the contaminants, the gait of the person, the cross section of the heels, the length of someone’s leg and so on. Therefore the HSE / HSL has evolved the Floor Pendulum Test to consider just 2 prime situations – with Shod Heels (96 Rubber) or with Bare Feet (55 Rubber) and arrived at a PTV, which covers virtually every possibility to give a theoretical and ideal minimum probability of slip of 1 in 1 million – that value is a PTV of 36 using 96 Rubber and 55 rubber (55 at certain temperature ranges) on a horizontal floor.
is a more accurate method to determine the slip relations ship between specific floor types and shoe materials and contaminants but Ramp Testing expects (1) the flooring area tested for; (2) the shoes tested against and (3) the contaminants used must always be the same once the relationship is proven, which in general terms is impossible to control.
When the heel starts to slip (The heel is the body area considered as where slips start) then the foot goes forward and the body goes backwards. But in a fall the foot stays still and the body goes forwards. So you can generally determine, from a person’s injury if they’ve slipped or tripped. False claims might say, for example, “The person slipped on the wet floor and banged the front of their head”, where, in reality a person slipping would have fallen backwards and banged the back of their heads!