Slip Resistance Explained: PTV, R Values and What the Label Says
How the HSE grades slip potential from the pendulum test, what EN 13893 covers, what R11 on two of the tiles means, and which figure fits which room.
Slip resistance is the characteristic people ask about for a bathroom or a kitchen, and the one with the most confused answers, because three different measurements are sold under one word. A porcelain tile listing says R11. A declaration of performance carries a slip line measured on a dry surface. A safety officer talks about a pendulum test value. None of them converts into the others, and a floor chosen on the wrong one can be right on paper and wrong on the day. This guide sets out what each figure measures and which one is written for the room you are flooring.
On this page
- The pendulum test: how the HSE grades slip potential
- The declaration's slip line: EN 13893, dry only
- The R value on a tile
- Surface texture and what it does
- Which measurement for which room
- Cleaning changes the answer
- Where laminate stands
- Common questions
- What the published standards say
- Who publishes this guide
The pendulum test: how the HSE grades slip potential
The Health and Safety Executive grades pedestrian slip potential from the pendulum test value, PTV, obtained with the pendulum coefficient-of-friction test that is the subject of BS 7976 Parts 1 to 3. The grading is in three bands: a PTV of 36 or above is low slip potential, 25 to 35 is moderate, and 0 to 24 is high. The pendulum swings a rubber slider across the surface and the value is read off a scale; the test can be run wet as well as dry, which is why it is the measurement used where floors get wet in use and why it is the figure a specification for a public building or a workplace is written around.
For a home the value is rarely quoted on a product listing, and the HSE's bands are written for workplaces rather than private bathrooms. What they give a domestic buyer is a scale to ask about: a floor sold for wet areas with a published wet PTV is making a testable claim; a floor sold as "slip resistant" without a figure is not.
The declaration's slip line: EN 13893, dry only
Under EN 14041, slip resistance is one of the essential characteristics a resilient, laminate or textile floor covering declares on its declaration of performance. The method behind it is EN 13893, which measures the dynamic coefficient of friction of a floor covering walked on with shoes, and which measures on dry surfaces only. So the line on the declaration answers one question, whether a dry floor of this kind is slippery underfoot, and it answers nothing about the same floor with water on it. Reading a declared dry-friction figure as a promise for a wet floor is the commonest mistake on this subject, and the declaration of performance guide covers what the rest of that document does and does not say.
The R value on a tile
Two of the eleven porcelain tiles in the range, the Wabi Bianco and Wabi Sabbia lappato tiles, list an R11 slip resistance. The R scale comes from a different method again, a ramp test rather than a pendulum, and there is no conversion between an R class and a PTV. What a buyer can take from it is a relative statement: within the R scale, a higher class is a more slip-resistant surface. What a buyer cannot take from it is a wet PTV, because the tile was not tested that way, and a bathroom specification that asks for a pendulum value should be answered with a pendulum value.
The other nine tiles list no slip figure. That is not a mark against them; it is the manufacturer declining to make a claim. Polished porcelain, which is five of the eleven, is chosen for its surface, and a polished surface is a different proposition in a wet room from a matt or lappato one. The tile guide sets out what the tiles in the range are; this page's point is only that the slip figure, where one exists, comes from a named test and should be quoted with it.
Surface texture and what it does
Of the 36 rigid vinyl floors in the range, 32 list a textured surface. Texture is not a slip rating and it is not on any declaration, but it is the property that the ramp and pendulum tests respond to: a surface with relief gives a shoe or a foot something to bear on when there is a film of water between them. A smooth, gloss surface has less of it. The same holds for the lappato tiles against the polished ones, and for a brushed oak against a smooth lacquered one. Texture is a reasonable thing to prefer for a room that gets wet; it is not a figure, and it should not be quoted as one.
Which measurement for which room
Cleaning changes the answer
A floor's slip behaviour is not fixed at the factory. Polish, residue from the wrong cleaner and a film of soap all change the surface a foot meets, and the association that represents multilayer modular flooring makers, the MMFA, requires low-moisture cleaning and says that pooling of liquid on the floor must be avoided under all circumstances. The rigid vinyl cleaning guide and the wood floor care guide cover the methods; the point here is that a slip-resistant surface stays one only if it is cleaned in a way that leaves it as tested.
Where laminate stands
Laminate declares its dry-friction line like any other covering under EN 14041, but its product standard, EN 13329, does not cover areas subject to frequent wetting and names bathrooms, laundry rooms and saunas. So for laminate the wet-slip question does not arise, because the wet room is not a room it is made for; the AC rating guide covers what its rating does measure.
Common questions
What PTV counts as low slip potential?
The Health and Safety Executive grades a pendulum test value of 36 or above as low slip potential, 25 to 35 as moderate and 0 to 24 as high. The test is the pendulum coefficient-of-friction test in BS 7976 Parts 1 to 3.
Can I convert R11 into a pendulum value?
No. The R scale comes from a ramp test and the PTV from a pendulum test; they are different methods and there is no published conversion between them. Ask for the figure your specification is written around.
Does the slip line on a declaration of performance apply when the floor is wet?
No. The method behind it, EN 13893, measures the dynamic coefficient of friction on dry surfaces only. A wet-floor question needs a wet pendulum value or a ramp-test class.
Is a textured floor the same as a slip-resistant one?
Texture is the property the slip tests respond to, but it is not a rating and it is not on any declaration. Prefer texture for a room that gets wet; quote a figure only where a named test produced one.
Which rooms get wet, and how often, differs between a terrace with one bathroom and a house with three. Browse by town and region.
What the published standards say
Who publishes this guide
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