The Ceramic Tile Institute has categorized the degree of slip resistance in three levels:
- Slip resistant with a COF of .6 or greater when wet. This is good for general health regulations.
- Conditionally Slip Resistant which has a COF of .5 to .59
- Questionable if it has a COF less than .5
Ceramic Tile Institute of America. "IMPROVED SLIP RESISTANCE TESTS." 24 January 2008. CTIOA Ceramic Tile Institute of America. PDF. 25 June 2014.