Testing and measuring slip resistance


Making sure that slip resistance is tested as accurately as possible is really important to us, alongside sharing the information you need to make informed and safe choices.

While there are lots of different methods of testing, we combine them to get the most accurate proof of how our flooring solutions perform. This means we can give reliable evidence of how pioneering our flooring is and reassure our customers that that are in safe hands.

The most common and reliable methods of testing slip resistance are outlined below.

The Pendulum Test (BS 7976)

The 'pendulum' is a swinging, dummy heel that sweeps over a set area of flooring in a controlled manner to simulate slipping on a wet floor. The slipperiness of the flooring has a direct and measurable effect on the pendulum value. Flooring that achieves a wet result of ≥36 on the Pendulum Test has a low slip potential. At Altro we offer safety flooring for shod areas that exceeds the ≥36 rating, indicating the lowest potential for a slip, with a slip risk of just one in a million.

The Pendulum Test Value (PTV) gives an accurate indicator of floor surface slipperiness. Additional information from surface microroughness readings can also be obtained.

PTV Potential to slip classification Risk 1 in:
≥36 Low 1,000,000
34 Moderate 100.000
29 Moderate 10.000
27 Moderate 200
24 High 20
18 High 2
Source: Ciria, Safer Surfaces to Walk on

Surface Microroughness Meter

The total surface roughness of flooring material is measured using a microroughness meter, which measures in Rz microroughness values (microns). It traces a needle over different areas of the flooring, taking peak to valley measurements to calculate surface microroughness. A surface roughness of 20 microns or above implies a low slip risk.

Health and Safety Executive Slip Assessment Tool (SAT)

You can download free software from the Health and Safety Executive Slip Assessment Tool (SAT) which helps you carry out a risk assessment with a surface microroughness meter, so you can get a slip risk classification for a floor.

The Ramp Test

DIN 51130

The Ramp Test is widely used, and its 'R' values are quoted by most flooring companies. R9 to R13 values are based on angle measurements of a motor oil-covered ramp that an operator, wearing work boots, walks on. The angle at which the operator slips forms the R value, but because the most common contaminant on floors is water not oil, and most of us don’t wear safety boots in our day to day business, the ramp test doesn't give a true representation of what happens in real life situations.

We believe R values don't tell you the whole story, and need to be viewed alongside other measures. For example, the R10 category spans a huge range of slip resistance. Within this category you will find products that offer slip resistance only for areas with low slip risk, as well as those with much greater slip resistance that are more likely to be suitable for areas with high slip risk, and most likely manufactured using very different methods. Yet all these products are broadly rated ‘R10’.

Why the Ramp Test can be confusing…R9 Is Not Fine!

It's often assumed that the scale of R values starts at R1 and ends at R13 – R1 being a measure of the greatest slipperiness. So an R9 value is often thought to indicate a surface that provides good slip resistance and some manufacturers don't try to dispel this misunderstanding. The truth is that R values start at R9, and it indicates the least slip resistance.

Where you see R10 AND a corresponding PTV ≥36 together, as with Altro safety flooring, you can be sure of the slip resistance of the product. Our specialist solutions for very high risk areas all have an R11 rating or higher.

R Classification Angle range necessary COF
9 6 - 10° 0.11 - 0.18
10 10 - 19° 0.18 - 0.34
11 19 - 27° 0.34 - 0.51
12 27 - 35° 0.51 - 0.70
13 >35° >0.70

DIN 51097

A barefoot version of the test (DIN 51097) also exists, using a 0.1 % soap solution as contaminant. This simulates conditions in a shower and cannot be used to measure installed floor coverings. It is reported as A, B, C.

Class Ramp angle COF
A 12 - 17° 0.21 - 0.31
B 18 - 23° 0.32 - 0.43
C >24° >0.44

SATRA Pedatron Test Machine STM 528

The SATRA Pedatron Test measures the effect of one million steps over a confined area of flooring, using a shoe with standard sole. It's used to measure flooring surface wear. Accurate wear patterns are produced by studying and replicating different walking gaits, incorporating straight and turning steps.

At Altro, we invest in this test as yet another accurate way to measure sustained slip resistance.

European tests

These tests are:

  • EN 13893 – a pull sled test where the requirements are a coefficient of friction of ≥0.30.
  • EN 13845 Annex C – a ramp test similar to DIN 51130 and DIN 51097 using water and soap as the contaminant and the classification is either Enhanced Slip Footwear (ESf) and/or Enhanced Slip Barefoot (ESb).
  • EN 13845 Annex D Wear Test – gives a measure of sustained slip resistance by counting particles over a given area after wear on an ex-factory flooring sample. If it exceeds 50,000 cycles it is awarded the top classification 34/43 and classed as very heavy commercial/heavy industrial.  Altro safety flooring passes the 50,000 cycle test classification.

    We recommend that whenever this information isn't provided for flooring for high or medium slip risk areas, you should ask a manufacturer for the specific number of cycles that the flooring has passed as an indicator of that product's level of sustained slip resistance. The only industry standard for long term slip resistance is EN 13845.

What do the results of slip resistance tests actually mean?

Manufacturers send ex-factory materials to independent test houses to certify that their products are slip-resistant. This means the results can be based on flooring that has a thin coating or emboss which was applied to increase the level of slip resistance for the test.

We believe that these thin levels of slip resistance can wear off in just a few months. And this leaves a much less slip-resistant surface which could fall significantly below recommended levels. If this happens, the floor could be unsafe. This is why we believe that the only true way for a floor covering's performance to be measured is when it's already installed and has been so for some time.

'Polyvinyl chloride floor coverings with particle based enhanced slip resistance – Specification', is the test for the European standard that covers slip-resistant flooring. To be classified as a PVC safety floor, we believe the product must conform to this standard.