Slip resistance: Evaluating the static Coefficient Of Friction (COF) of ceramic tile, ASTM C1028-06.
The COF numerical index rating defines the relative slip resistance of floor surfaces. Tiles used on Commercial and Residential floors should provide a safe walking surface in both wet and dry conditions. The tile industry uses ASTM C1028-06 to measure the COF.
The procedure involves the use of a calibrated dynamometer, a specialized neolite heel assembly, a standard reference tile surface and a 50lb weight. This procedure measures the maximum force required to initiate motion in the testing assembly in four perpendicular directions. The values are recorded and an averaging calculation is performed that determines the static COF.
Although there is no current ANSI requirement, a COF of 0.50 or higher is the‘recognized’ standard set for a slip-resistant floor.
The Americans with Disabilities Act (ADA) recommends a COF rating of 0.60or higher on level floor surfaces and 0.80 for access ramps on commercial and residential buildings.
The COF of a tile is a numerical index rating. The higher the COF rating; the higher the slip-resistance of the tile in dry and/or wet conditions.
As a general guideline, unglazed flooring tiles are more slip-resistant than glazed floor tiles.
The texture of the glazed surface will also affect the COF rating. Some manufactures will add abrasive content to their glazes increasing the COF rating
The slip resistance of a tile becomes an important factor when tile is being selected for areas that are subject to grease, exposed to water, have access ramps, and in most public spaces.