Why Floors Become Slippery: The Six Factors Behind Every Slip

Floors become slippery because of six factors working together: contamination, heel, individual, maintenance, environment and surface, known together as CHIMES. Any one of these factors can push a floor’s real world slip risk higher, and a floor that looks clean and dry can still fail on several of them at once. Understanding all six is the starting point for actually managing slip risk, rather than guessing at it.

The reader’s reality

If you manage facilities across hospitality sites, you’ve probably relied on a simple test for years: does the floor look clean and dry. If it does, it feels reasonable to assume it’s safe. That assumption is understandable, but it only checks one small part of a much bigger picture.

Slip resistance isn’t determined by appearance. It’s determined by a combination of factors that interact constantly, some of which have nothing to do with cleaning at all. This article sets out the CHIMES framework, the six factors that actually explain why floors become slippery, so you know what to look for rather than what to assume.

What is CHIMES?

CHIMES is a framework for understanding what drives slip risk on any floor. Each letter represents one factor that contributes to whether a floor is genuinely safe underfoot, not just whether it looks that way.

No single factor tells the whole story on its own. A floor can score well on one and poorly on another, which is exactly why relying on a visual check misses so much.

Why does contamination make floors slippery?

Contamination is the most visible factor, and often the one people focus on entirely. Water, grease, food debris and dust all reduce the friction between a shoe and a floor surface. In busy hospitality environments, contamination isn’t an occasional problem, it’s a constant one, arriving with every spill, every delivery and every shift.

The trouble is that contamination is only dangerous in combination with a floor that can’t cope with it. A floor with strong measured slip resistance can handle a reasonable level of contamination safely. A floor with poor underlying grip can become dangerous with barely any contamination at all. Treating contamination as the whole problem, rather than one part of it, is how most slip prevention efforts fall short.

Why does footwear affect slip risk?

Heel refers to the footwear people are actually wearing, and how well it grips the floor in the conditions present. Different sole materials and treads interact very differently with the same floor surface, particularly once contamination is present.

This matters more in hospitality than it might first appear. Staff footwear can be specified and controlled, but visitors and customers wear whatever they choose, from trainers to high heels to sandals. A genuinely safe environment has to work across that whole range, rather than assuming everyone will be wearing appropriate shoes. Blaming a slip on someone’s footwear after the fact rarely holds up, since the environment has to be safe for the footwear people can reasonably be expected to wear.

Why does the individual matter for slip risk?

The person walking on the floor is part of the equation too. Pace, distraction, mobility, fatigue and general awareness all affect how someone responds to a hazard, and how much warning they need to avoid it. Someone rushing between tables during a busy service has less capacity to notice a wet patch than someone walking slowly and paying close attention.

This factor is often where blame gets misplaced. It’s easy to say someone should have been more careful after a slip has happened. It’s far more useful to design the other five factors so that ordinary human behaviour, including rushing, distraction and tiredness, doesn’t turn into an incident.

Why does maintenance affect floor grip?

Maintenance covers the cleaning products, methods and frequency used to care for a floor, and it has a more direct effect on slip resistance than most people expect. Cleaning removes visible contamination, which helps. But the wrong product can leave a residue that reduces grip, even while making the floor look shinier and cleaner than before.

This is where the old belief that looks clean equals safe breaks down completely. A floor can be mopped thoroughly, look spotless, and still perform worse than it did before cleaning, if the product or method wasn’t suited to that specific floor. Maintenance needs to be chosen with slip resistance in mind, not just appearance.

Why does environment increase slip risk?

Environment covers everything around the floor itself: lighting that makes a spill hard to spot, gradients and transitions between different flooring types, and weather conditions that bring water or mud in from outside. A floor with perfectly good slip resistance can still contribute to an incident if nobody can actually see the hazard on it in time to avoid it.

Environmental factors are easy to overlook because they don’t involve the floor surface directly. A poorly lit corridor, an uneven transition between tile and carpet, or an entrance that floods every time it rains are all part of the picture, even though none of them are strictly about the floor material itself.

Why does the surface matter more than any other factor?

Surface is the floor itself, and its actual measured slip resistance under realistic conditions. This is the factor most commonly assumed rather than tested, and it’s the one that determines how much risk the other five factors create in combination.

The difference between a poor and a good surface score is much larger than most people expect. Moving a floor’s Pendulum Test Value, or PTV, from 24 to 36 or higher when wet is associated with a reduction in slip risk of around 50,000 times, based on Slip Safety Services testing data. That’s not a marginal improvement. It’s the difference between a floor that’s genuinely dangerous when wet and one that isn’t, regardless of how well the other five factors are managed.

What good looks like

A hospitality site that manages all six CHIMES factors properly doesn’t rely on appearance to judge safety. The floor has a known, tested PTV score, rather than an assumed one. Cleaning products and methods are chosen with that score in mind. Lighting and transitions are checked as part of the same assessment, not treated as a separate issue. Staff understand that footwear and behaviour matter, without being expected to compensate for a floor that was never actually safe to begin with.

Retesting happens whenever conditions change, whether that’s a new cleaning supplier, a change of flooring, or a shift in footwear policy. And when a facilities manager is asked how safe their floors are, the answer comes with a number attached to it, not just a visual impression.

The new belief

Looking clean has never been the same thing as being safe. Slip risk comes from six factors working together, and only one of them, the surface itself, can actually be measured with a test. Understanding all six, rather than assuming the ones you can see are the ones that matter, is the real starting point for genuine slip prevention.

Take the next step

If you want to know how your own floors measure up against these six factors, the Slip Risk Scorecard is a quick way to find out where to look first. For the full method behind assessing and improving slip risk properly, Slipology sets it out in detail.

FAQ

What are the six factors that cause slippery floors? The six factors are contamination, heel, individual, maintenance, environment and surface, known together as CHIMES. Each factor contributes to a floor’s real world slip risk, and a floor can perform poorly on several of them even if it looks clean and safe.

Can a clean floor still be slippery? Yes. A floor’s slip resistance depends on its measured surface performance, not on how recently it was cleaned. Some cleaning products leave a residue that reduces grip while making the floor look cleaner, which is why appearance alone cannot confirm safety.

Which CHIMES factor matters most for slip risk? No single factor works in isolation, but surface slip resistance determines how much risk the other five factors create. A floor with strong measured grip can handle everyday contamination and footwear variation far more safely than a floor with poor underlying resistance.

How do I find out my floor’s actual slip resistance? The only reliable way is a pendulum test, which measures how a standard test foot interacts with a floor surface under realistic wet or contaminated conditions. This produces a Pendulum Test Value, or PTV, a number that tells you what a visual inspection cannot.

Does footwear alone explain why someone slipped? Rarely. Footwear is one factor among six, and blaming a slip on footwear after the fact often overlooks contamination, surface grip, maintenance and environmental conditions that contributed just as much, if not more, to the risk.

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