Slip Resistance
Slip safety of stair surfaces, classified per DIN 51130.
Slip resistance describes the property of a stair tread surface to prevent slipping. Classification follows DIN 51130 in the R classes from R9 (low) to R13 (very high). For interior stairs, R9 is generally sufficient; for outdoor stairs, R10 to R11 is recommended. Slip resistance can be achieved through material selection (e.g. flamed natural stone), surface finishing (e.g. brushing) or retroactive measures such as step profiles or anti-slip strips.