ASTM C-1027 describes the standard test method for determining visible abrasion resistance of glazed ceramic tile. The classifications are 0 thru 5 sometimes referred to as the PEI Ratings.

Class O - Decorative use only, Not recommended for use on floors

Class I - Light Traffic, for residential bathroom floors, no direct outside access

Class II - Medium - Light Traffic, residential interiors with the exception of kitchens, stairs, landings and areas near external entries

Class III - Medium - Heavy Traffic, All residential applications. Commercial applications which are similar in traffic to residential applications. Specifically excepted are areas of prevalent circulation or turning points

Class IV - Heavy Traffic, all residential and most commercial applications such as the public areas of exhibition halls, hotels, restaurants, supermarkets, shops and schools

Class V - Extra Heavy Traffic, all residential and commercial applications similar to class IV where extra durability may be required. Commercial usage, Industrial Applications.