Static Coefficient of Friction tests
The HSE new STEP wesbite reviews a number of test machines that each test static coefficient of friction. Some of these are very popular machines and written into international standards, but the HSE claim that these types of machines do not work.
Slip test machines compared
We have compiled a list of slip test machines from America, Europe UK, and Germany and some comparison of slip testing. We'd welcome your comments.
HSE new interactive website, STEP, comments on various other slip test machines. The GMG test, the Brungraber MkII, Tortus and FSC2000 work in a similar way. Some of these tests are still included in international standards and results are quoted in manufacturers' data sheets. It is important to note that the HSE does not accept these tests as a valid method for assessing the slip resistance of floor surfaces as they provide inaccurate data in contaminated conditions.
Many slip test machines fail to travel quickly enough and therefore cannot simulate a real slip on a wet or contaminated floor.
The SlipAlert test measures dynamic CoF (coefficient of friction) and can be used to test the slip potential of clean and dry, or contaminated floors. SlipAlert travels down a ramp and reaches the same speed as the TRL Pendulum swing. This is crucial for creating the "squeeze film" that often causes slips. The squeeze film (water or other contaminants) lifts the heel off the floor (like aqua-planing ) and hence the foot moves quickly and the pedestrian lands virtually the same spot they began to slip.
When operated correctly, the SlipAlert test produces valid results and is a useful tool for obtaining a simple measure of CoF, risk assessment and monitoring of floor surfaces and cleaning regimes.
"The extended testing of SlipAlert showed a
good correlation with the Pendulum test"
"SlipAlert should be regarded as a good indication of available friction, lending itself to risk assessment, monitoring of floor surfaces and evaluating & monitoring cleaning regimes"
Rz Microsurface Roughness
Micro surface roughness measures will remain unaffected by contamination making it useless as a way of measuring the effectiveness of cleaning regimes or as a tool to explain why one area of a floor appears to be a slip hazard. Roughness machines such as the Taylor Hobson Surtronic Duo were designed for measuring microsurface imperfections on metal, not designed for measuring floor slip risk. more on Rz
There are 2 main types of ramp test. Both incline the floor until a human foot begins to slip. The UK ram test involves a man in shoes walking on water wet floor. The German ramp test uses boots and oil as the lubricant. R number ratings relate to the German ramp test. One problem with this test method is that it canot be used on an installed floor. contact us for more information.
Other slip test machines
Beware of any slip test machines that do not offer correlation with TRL Pendulum in wet and dry slip tests. The Pendulum Skid Tester has been shown to reflect real slip experience. SlipAlert was designed to match the Pendulum in both wet and dry tests and on all hard floors: vinyl, concrete, resin, tiles, wood flooring, stone, terazzo, marble, linoleum. SlipAlert also tests outside surfaces asphalt, roads, paths, walkways, slabs, decking.
Testing outdoor slip ressitance