In very simple terms, if you have perfectly clean and perfectly dry floors, it’s almost impossible for somebody to slip. For a slip to occur, some contamination must be present.


If we think about the traditional hierarchy of control measures around accident prevention, the first step is elimination. If you can eliminate that contamination from being present on the floor (or on the heel), achieving a flawlessly clean and perfectly dry environment, then you will in all likelihood see zero slips.


What does contamination mean; how do we look for it? One of the first things to be aware of is that water is a contaminant. So, a spillage of water would be a contaminant, but also water on a poolside or on a shower floor would be a contaminant, just as water externally on a pavement would be a contaminant. There are other contaminants that can make floors slippery without water even being present, which would include grease, body fats, or dry contaminants. If you have a smooth, dry floor with a lot of dust, the effect of the dust can be to make the floor slippery, even though there’s no liquid present. This is why when we think about the risk management for slip safety, as well as the quantification of floor safety, we always refer to a floor being wet or contaminated, not simply just wet.


How – or to what extent – can contamination be controlled? It’s going to very much depend on the environment that you’re operating.

  • If you are operating an external plaza outside an office, it’s impossible for you to eliminate the water contamination from that floor: it’s outside, it’s open to the elements, we live in a country where it rains a lot, and therefore that floor is going to get wet.
  • If you are operating leisure facility (poolside and changing rooms) or somewhere that has showers in it (even in an office building), again it’s impossible for you to prevent that floor at all times from getting wet.
  • If you are operating a kitchen, it’s impossible to prevent some grease from building-up onto your floor at some point in time. The floor is also likely to get water on it.
  • If you are operating a facility where dust or other kinds of dry debris might get on the floor, these can make the floor just as slippery as water.


There are certain environments where it is more foreseeable that the floor will be contaminated, whereas other environments – indeed the majority of floors – have a much lower risk.


The way to manage contamination will also vary by sector and contamination type as well as environment. So, taking a manufacturing facility, it might be possible to use a drip tray to prevent oil contamination, let’s say, from coming off some machinery onto the floor, and that would be an effective way of eliminating contamination. In the entrance to a building your entrance system, which we will also talk about under the topic of environment, can be a way of eliminating contamination. If you have an entrance with a very large canopy, several sets of doors and dozens of metres of entrance matting, it’s very unlikely that by the time someone’s foot strikes your floor, it will be contaminated.


Contamination can be a surprise or one-off event such as a spillage, or it can take the form of something that builds up over time day after day. If you have known contamination then you should try to tackle that either at source to eliminate it, or through maintenance.


On the latter point, cleaning is clearly an important control measure. In simple terms, if you have an inherently slip-resistant floor, if you can clean your floor to prevent any build-up of contamination, the risk of someone slipping even if there is one-off contamination such as a spillage should be very low.


There are ways of quantifying contamination to help you to create the right strategy for your different environments.

  • Undertaking a pendulum slip test will help you to understand the level of contamination on your floor – a clean floor is likely to achieve a higher PTV than a contaminated one.
  • Swab testing or similar will measure the number of microorganisms on the surface. This can be useful because certain types of contamination aren’t immediately visible to the naked eye.
  • There’s also of course a very simple aesthetic test which is more qualitative that you can do. Does the floor look clean? Is it consistent in its finish? Do you know what the floor should look like out of the box?


Often, we can perceive that a floor is clean if it is consistently covered in contamination of some kind, but in such a way that it doesn’t look horrendously dirty. Throughout our website you will see example photographs showing floors which probably appeared to be clean to customers but when effectively cleaned their level of risk reduced dramatically.


Some practical points to consider. If you have one-off contamination in the form of a spillage then think carefully about how exactly you deal with this. Your objective should be to remove that spillage and turn the floor back into a clean and dry state as quickly as you possibly can. What we see a lot of, in terms of poor practice, is getting a traditional Kentucky mop and mopping the area of the spillage as well as, normally, the surrounding area. This tends to heighten the risk because, rather than having a small contained spillage which could be visible to somebody walking across the floor, you instead have a larger much thinner layer of contamination which is potentially not visible at all, This presents a much greater risk, bearing in mind that only the smallest amount of liquid between the heel and the floor will trigger someone to slip, whilst in this scenario the fact that the floor is contaminated may not be immediately apparent to someone walking on it.


Where you have full, consistent contamination build-up, so let’s say grease, think about ways of trying to eliminate that from being on the floor. So we spoke about grease traps, but also about cleaning.


When it comes to cleaning, the key word is effectiveness and effectiveness may not be following the recommendations that floor supplier or cleaning company gives you. You need to be able to measure the impact that your cleaning regime is having on the floor to ensure that it is truly effectively removing contamination from the floor and preventing contamination from building up.


So, don’t just assume that your method is fit for purpose or your product is fit for purpose. Even if that has been advised to you by a chemical manufacturer, it may well be that they have never actually explored in any scientific way, the extent to which their process actually suppresses the build-up of contamination.