How is Porcelain Tile Rated for Hardness?

Most reputable lines of porcelain tiles are rated for use by the Porcelain Enamel Institute (PEI) abrasion test. This test is recommended by the American Society for Testing and Materials (ASTM). The scale provided by this test determines the resistance of an enameled surface in relation to the traffic and wear the surface can endure, without any damage to its appearance.

Known as the PEI Scale, it is the standard consumers can rely on and refer to in order to determine which tiles to buy according to purpose and location. The PEI rating indicates the tile hardness, and these ratings are valuable to help in tile choices for different projects. However, the wear rating of the tile does not influence the quality or price, but only durability. Some of the most expensive and luxurious tiles in the world fall in group I or II.

The following information is based on the Porcelain Enamel Institute�s guide to rate the overall durability of ceramic tile:

Group 0: Tiles technically unsuitable for floors. These are generally used as wall tile.

Group 1 or PEI 1: Tiles suitable only for locations where softer footwear is worn or where shoes are not frequently used, for e.g., residential bathroom or other areas with light traffic. Also for interior commercial and residential walls.

Group 2 or PEI II: Tiles suited for general residential traffic. For areas that are walked on by soft soled or �normal� footwear with very small amounts of scratching dirt. Not for kitchen, entrance halls, stairs and other areas subjected to heavy traffic.

Group 3 or PEI 3: Tiles suited for all residential and light commercial areas such as offices, reception areas, boutiques, interior walls, countertops and residential bathroom floors. Not recommended for commercial entryway.

Group 4 or PEI 4: Tiles suited for regular traffic. Recommended for medium commercial and light institutional use, such as restaurants, hotels, hospital lobbies and corridors.

Group 5 or PEI 5: Tiles suitable for areas with heavy traffic, abrasive dirt and moisture, and where safety and maximum performance are required. Examples are shopping malls, public buildings, building entrances, swimming pools, or shopping centers.