The Porcelain Enamel Institute (PEI) has developed a rating scale that can effectively guide any consumer through the process of choosing the right tile for their particular application.
PEI Class 0 Rating (no foot traffic) - Wall tile only and should not be used on floors.
PEI Class 1 Rating (No foot traffic) - Recommended for wall use only .
PEI Class 2 Rating (Light traffic) - Recommended for both wall use and bathroom floor applications (Master bath, spa bathroom).
PEI Class 3 Rating (Light to moderate traffic) - Recommended for countertops, walls, and floors where normal foot traffic is expected. Any residential area with the possible exception of some entries and kitchens if extremely heavy or abrasive traffic is anticipated.
PEI Class 4 Rating (Moderate to heavy traffic) - Recommended for all residential applications as well as medium commercial and light institutional.
PEI Class 5 Rating (Heavy traffic) - Recommended for all residential as well as heavy commercial and institutional applications.
Most porcelain tiles have a PEI rating of 5, which makes them the hardest wearing tiles on the market.