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As phisics students know very well, friction is not a conservative force ( in other words a force that loses energy in its various forms). Friction is actually a very important factor, eventhough it can be seen as a negative phenomena as it is that power that makes us consume energy. For example, without friction our cars would not be able to stay on the road, airplanes would not flight and so on.
From a physics point of view we can talk about static friction and kinetic one.
The first one ( static friction) represents the power that has to be won in order to make a body move; the second one (kinetic friction) is the minimum power that is needed to maintain a body in motion. The static friction is always superior to the dinamic one, plus static friction is the one we have to take into consideration when we are talking about slipperiness of surfaces.
In laboratory the static friction coefficient is determined by positioning a body over an inclined plane and then measuring the angle of inclination through which the body is put in motion. Static friction coefficient corresponds to the trigonometric tangent of the inclination angle.
Is therefore clear how the friction coefficient is a pure number, meaning a dimensionless factor that has not a measurement unity. In daily practice the dynamometer allows us to calculate the static friction coefficient.
First we put the dynamometer on the surface, then we apply tension to the cable that is connected to the dynamometer and, when the block moves, the pointer indicates the static friction coefficient that had to be won in order to put the body in motion. It is very important to remember that the friction coefficient reduces itself in presence of water or wet surfaces.
Let’s now try to understand what angle of inclination and friction coefficient mean in real life: in other words let’s try to understand what are the conditions that make someone slip.
The angle of inclination corresponds, with good approximation, to the angle that is formed between the right leg and the left one wen we walk. Studying the outgoing of the values of the tangent to the inclination angle we can see that the value of the tangent 0 is zero, and that with the increase of the angle the value of the tangent increases aswell.
This means that if we are on a surface and we slip even if we are just standing, the angle between our legs will measure zero degrees, therefore the friction coefficient will be zero too. This means that we are on a extremely slippery area as in case of icy surfaces.
Some researches made in the United States have revealed that the angle formed between the hips during normal deambulation is normally stable around 27 degrees. This means that it is very rare that we split our legs for more than 27 degrees when we walk.
Again in the USA there are regulations defining criterias to determine when pavements are slippery and therefore dangerous for pedestrians.
The law ASTM D 2047-93 says that pavements can be defined as secure when they exceed the values that we are about to show in the following table in wet conditions.
Now in shops are available different systems to make surfaces secure and safe to walk on. They are mostly based on the roughening of the surface even though the ways to reach this result can be various. There are three main ways that can be used to make a surface rough:
It is mostly important to consider the time factor when making anti-slip treatment: in fact if I have to treat a shower plate or a swimming pool edge the reaction time is very important and it must be kept into consideration.
In the shower plate case I can use a very short reaction-time product set around 30 minutes. Instead when I have to treat larger areas, as in the case of the swimming pool edg,e is highly suggested to use a longer reaction-time product in order to obtain a more homogeneous result.
In the following table are shown the steps to follow during the anti-slip treatment for ceramic surfaces.
Anti-slip treatment itself must always be proceed by a careful and complete cleaning of the surface that can be made with a descaling acid. This helps removing dust, dirt and encrustations from the floor therefore allowing a direct contact between the anti-slip product and the surface.
The anti-slip product must be sprayed directly on the surface by an atomizer and then left for a sufficient time until a safe friction level is reached.
In this phase is mostly important that operators keep the treated surface constantly wet in order to obtain a more homogeneous result.
Once the desired friction level is reached, the treatment product must be neutralized by a neutralizer product that has to be sprayed over the treated surface and then washed off carefully.
In the end with the Slipmeter we can check the values of static friction over the pavement. We could also make a report with all the values surveyed before and after the treatment to give them to our client.
It does not exist in Italy a law defining when a surface can be determined as secure; anyway there is the Law 626/94 that at the article n. 33 says that pavements must be generally anti-slippery. Therefore demand of anti-slippery pavements is growing constantly.
This demand is associated also to the general and favourable selling trend of glazed stoneware tiles which are conquering the market over other materials.
Moreover production is oriented on producing tiles with a very deep vitifrication of the surface that makes them therefore much more slippery.
Anti-slip treatment is requested in all those areas with high pedestrian traffic and with wet surfaces. The swimming pool edge represents a classic case, but also dressing rooms, gyms, shopping centres can be good examples as well.
As you can see there are high chances and various possibilities; in fact this is a completely new sector for the Italian market and competitors are still few.
All this represents a good opportunity for those services businesses and entrepreneurs that can recognize favourable market trends.
Notes on the rights and citations
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