Identify the outdoor areas used by pedestrians which are most likely to be affected by ice, eg building entrances, car parks, pedestrian walkways, shortcuts, sloped areas and areas constantly in the shade or wet. Rock salt (plain and treated) is the most commonly used ‘grit’. It is the substance used on public roads by the Highways Agency and is available form builders’ merchants. Salt can stop ice forming and cause existing ice or snow to melt. It is most effective when it is ground down, but this will take far longer on pedestrian areas than on roads.
Gritting should be carried out when frost, ice or snow is forecast or when walkways are likely to be damp or wet and the floor temperatures are at, or below, freezing. The best times are early in evening before the frost settles and/or early in the morning before employees arrive. Salt doesn’t work instantly; it needs sufficient time to dissolve into the moisture on the floor.
If you grit when it is raining heavily, the salt will be washed away, causing a problem if the rain then turns to snow. Compacted snow, which turns to ice, is difficult to treat effectively with grit. Be aware that ‘dawn frost’ can occur on dry surfaces, when early morning dew forms and freezes on impact with the cold surface. It can be difficult to predict when or where this condition will occur.
Dry surfaces, when early morning dew forms and freezes on impact with the cold surface. It can be difficult to predict when or where this condition will occur.
Where a floor is likely to be subject to frequent contamination, people should still be able to walk on it without the risk of slipping. See Assessing the slip resistance of flooring, which also describes the relevant British and European standards.
Safety floors have surfaces that are a little rougher than standard surfaces. This has two effects on the cleaning; firstly it can take a little extra time or effort to get the dirt off the floor and into the cleaning solution, and secondly, they tend to hold a little bit more cleaning solution when you take off the excess with a wrung mop. This can mean that when the water from the cleaning solution evaporates, it leaves a little bit of dirt behind, which you might notice if there are low spots on the floor where the residue tends to accumulate. To avoid this, remove as much of the cleaning solution as possible, perhaps by using a dry mop or a wet vacuum to leave the floor really dry. There is no evidence that safety floors can not be cleaned to a hygienic standard for food or medical environments.
Many acid-etch treatments use hydrofluoric acid. There are serious health risks associated with this. The life span of the treatments is generally extended by cleaning with a dilute version of the acid - which may introduce ongoing health risks. Acid-etch treatments can sometimes be effective in improving the slip resistance of hard floors (such as tiles) in wet conditions .- the acid works by dissolving part of the floor surface to provide greater surface roughness, and so has an effect on both appearance and lifespan. Acid etching products are often described in other ways, so be wary of any product that claims it can change the slip resistance of your floor without changing the appearance. There can be problems if the application is poor so the slip resistance doesn't actually change (usually given away by the lack of visual change), or if the etched surface wears quickly because of high traffic and the surface returns to its original level of slipperiness.
Metal profile surfaces can give some mechanical interlocking with a cleated shoe heel or sole, but this is not necessarily the case. Where there is no interlocking, eg with smooth shoe heel and sole surfaces, the surface roughness of the top of the profile can give a good indication of the overall slipperiness of the surface. Metal flooring is often much more slippery than expected. Users typically see a profiled floor surface as less slippery than a flat surface and may take less care than they would on a surface they see as slippery.
Mild steel generally has better slip resistance than aluminium because it is harder and tends not to wear smooth. Also, the surface roughness increases as the steel rusts.
Profiled surfaces do wear with use; the surfaces may become rounded and this reduces the slip resistance.
Surface roughness is the fine texture of a flooring material. As a simple test, consider whether the flooring feels more like paper or sand paper. The fine texture of sand paper would stop you slipping in the wet, whereas the smooth surface of paper would be slippery. The level of roughness can be measured and the level of roughness gives an indication as to how slippery the surface might be when wet. You can use roughness measurements with the Slips Assessment Tool to help with your risk assessment. (linked to SAT?)
There can be several steps to this – do you know the name of the flooring product, and if so, can the manufacturer supply you with a technical data sheet – these sheets are often provided online. If the manufacturer does not claim the floor is slip resistant when wet, then it will probably be slippery in wet conditions. Be wary if the floor is described as ‘R9’ as this means it will be slippery when wet.
Surface roughness can give an idea of how slip resistant a floor is (see previous question) but if you want to know for sure, the best way to measure slip resistance is to use the Pendulum test, as described by BS7976 and the UK Slip Resistance Group guidelines. There are numerous companies offering this testing as a service, but do think about whether they have an interest in showing you that you have problems.