The slip resistance value is a standardised measurement that indicates how slip-resistant a floor surface is, expressed as an R-value ranging from R9 (lowest resistance) to R13 (highest resistance).
Slip resistance is a critical safety parameter in construction. Selecting the correct floor finish for its intended environment helps prevent slips and falls — one of the most common causes of injury in buildings and public spaces.
How is slip resistance measured?
The most widely used test method in Europe is the ramp test defined in DIN 51130. A test person wearing standardised safety footwear walks back and forth on a sample floor surface that is gradually tilted and coated with motor oil. The angle at which the person can no longer walk safely determines the R-value:
| R-value | Minimum acceptance angle | |———|————————–| | R9 | 6 to 10 degrees | | R10 | 10 to 19 degrees | | R11 | 19 to 27 degrees | | R12 | 27 to 35 degrees | | R13 | above 35 degrees |
A separate barefoot ramp test (DIN 51097) is used for wet areas where people walk without shoes, such as swimming pools and showers. This test produces classes A, B and C, with C offering the greatest slip resistance.
Which R-value is required where?
Regulations and guidelines vary by country, but general recommendations include:
- R9 — dry interior spaces such as living rooms and bedrooms.
- R10 — toilets, entrance halls, kitchens and lightly wet areas.
- R11 — commercial kitchens, laundries and outdoor walkways.
- R12 — food processing areas, slaughterhouses and industrial zones with oily conditions.
- R13 — heavily contaminated industrial floors, fat-processing plants.
Factors that affect slip resistance
Surface texture, material porosity, the presence of water or contaminants, wear over time, and cleaning methods all influence how slip-resistant a floor remains in practice. Specifiers should consider both the initial R-value and how it will perform after years of use and cleaning.
Related terms
- DIN 51130
- Pendulum test value (PTV)
- Surface roughness
- Floor finish