According to ASR A1.5/1.2, appropriate protective measures must be taken to avoid slip hazards. Suitable floor coverings, e.g. coverings with a high slip resistance, are particularly suitable as protective measures. Floor coverings with the R9 rating group meet the lowest requirements and R13 the highest.
In Germany, slip resistance is regulated according to DIN 16165 (formerly DIN 51130). Slip resistance is measured on an inclined plane with a standardised shoe and lubricant. This is how the slip resistance classes R9 (lowest slip resistance) to R13 (highest slip resistance) are determined.