Coefficient of Friction

 Coefficient of Friction (COF) It has been a standard for all specifiers when considering a ceramic or porcelain tile for any floor application (especially a commercial environment) that the tile had to have a slip resistance of 0.6 wet or dry. This was in harmony with a suggestion that was made for the Americas with Disabilities Act (ADA) which was established in 1990.

According to access-board guidelines, the standard for slip resistance was never spelled out as an actual number, but rather provided (in part) the following information:

Accessible surfaces must be slip resistant to minimize hazards to people with disabilities, especially those who are ambulatory or semi-ambulatory or who uses canes, crutches, and other walking aids.  However, the standards do not specify a minimum level of slip resistance (coefficient of friction) because a consensus method for rating slip resistance remains elusive. Some flooring products are labeled with a slip resistance based on a laboratory test procedure.  Compliance with the standards requires specifying surface materials, textures, or finishes that prevent or minimize slipperiness under the conditions likely to be found on the surface.  Standard practices for minimizing floor or ground slipperiness will likely satisfy compliance with the standards as slip resistance is important not just for accessibility but for general safety as well.

Based on this a recommended standard was created as ASTM C1028 (Standard Test Method for Determining the Static Coefficient of Friction of Ceramic Tile and Other Like Surfaces by the Horizontal Dynamometer Pull-Meter Method) which recommended a slip resistance of 0.6 for a coefficient of friction (COF) wet or dry for all commercial applications.

However, as of February 1, 2014, the ASTM C1028 test standard has been withdrawn.  This is because a new and more accurate standard for slip resistance has been created.  The Tile Council of North America (TCNA) 2015 manual notes on page 19 that the new specification should include the following: " Tiles suitable for level interior spaces expected to be walked upon when wet shall have a wet DCOF of 0.42 or greater when tested per the DCOF Acu Test"

Therefore the updated ANSI A1371 standard now states "the specifier shall determine tiles appropriate for specific project condition, considering by way of example, but not in limitation, type of use, traffic, expected contaminants, expected maintenance, expected wear, and manufacturers guidelines and recommendations."

Since there is not correlation between the old COF values used for the ASTM C1028 standard and the new values as measured by the new DCOF Acutest, if you specify tile for any commercial application, it's important that you update your specification standards.

D9 Select tiles are vetted to make sure that they meet the new standards for slip resistance in a commercial environment. Please allow us to help you with any technical questions you may have regarding this or any other issue that involves the use of tile or stone.