How do slopes affect slip safety?

It sounds obvious to say that if you are walking on a slope you have a greater requirement for floor friction, but how much more friction? Should slopes be avoided where possible – and is there ever a point that a slope is so severe that it’s unsafe?

Many floors have slopes to assist with drainage (e.g. swimming pool sides, kitchens, external areas) but small slopes often cannot be discerned easily. Thankfully since the advent of smart phones, inclinometers are readily available to quickly and accurately measure what, if any, slope exists.

When using a pendulum to quantify the level of friction that a floor provides, the introduction of a slope changes the way you should interpret the results. Using round numbers, you add 1.75 PTV points to the requirement.

So, on a flat surface, a PTV of 36 gives low slip potential. But with a 2 degree slope, in order to achieve a low slip potential you require 36 + (2 x 1.75) = 39.5 PTV.

On the same 2 degree slope, to achieve moderate slip potential is no longer 25 PTV but 28.5 PTV.

Slopes with small gradients can be perfectly safe even when wet and / or contaminated provided the floor surface and its maintenance are sufficiently robust. You are often better with a low-gradient slope than a single stair, which can be unseen and therefore lead to mis-steps.

But very steep ramps can reach the point where it is not feasible to achieve and maintain a low slip potential. For example, the Slip Safety Services team once saw a ramp externally which had a gradient of 24 degrees(!). That means that in order to achieve even a moderate slip potential, the floor surface must be specified at and maintained to a PTV in dry and wet conditions of 67; to achieve a low slip potential it requires to achieve and maintain a PTV of 78. Very, very few surfaces achieve 78 PTV when wet and those that do are so textured that maintaining them there is almost impossible.

So, to summarise:

  • Slopes mean your need a greater level of friction (an additional 1.75 PTV per 1 degree of slope)
  • Slopes with small gradients can be perfectly safe
  • But if you can keep floors mostly flat, that lessens the requirement on the surface and its maintenance
  • Slopes with high gradients can reach a point of being unsafe

If you want to discuss your slip risk management, book a FREE Slip Safety Strategy HERE or call the expert team on 0203 355 5018 to discuss your requirements.

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