Abschnitt 2 - 2 Terms and definitions
Assessment group is a measure of the required level of slip resistance for floor coverings in wet use areas, which is determined by type examinations carried out according to German standard DIN 51097. Group A requires the least slip resistance and C the most.
Coefficient of sliding friction, µ, is the dimensionless quotient calculated from the horizontal frictional force and the vertically acting force between the slider and the horizontal floor during movement at a constant speed.
µZM is the coefficient of sliding friction for materials in a new condition, calculated according to German standard DIN 51131 using an SBR slider and SLS solution (ZM stands for zero measurement).
µCM is the coefficient of sliding friction for materials in operational condition, calculated according to German standard DIN 51131 using an SBR slider and SLS solution (CM stands for standardised control measurement).
Reference measurement is the determination of the µZM carried out as specified in German standard DIN 51131 (with an SBR slider and SLS solution) for a floor covering in new condition prior to building site clean-up (installed and grouted). The reference measurement value serves as a reference for comparisons with the condition of the flooring at later points in time.
Control measurement is the determination of the µCM carried out as specified in German standard DIN 51131 (with an SBR slider and SLS solution) for the floor covering in operational condition.
SBR slider is a slider (styrene butadiene rubber material) standardised according to German standard DIN 51131.
SLS solution is a lubricant standardised according to German standard DIN 51131 used for making determinations in a wet condition. The lubricant consists of a 0.1 % SLS solution (sodium lauryl sulfate) in deionized water.
Reserve sample is a sample of flooring retained from the batch installed (at least 2 m2) for later inspections.