The term P.E.I. rating is associated with the Porcelain Enamel Institute and not the tile industry. The appropriate term is Visible Abrasion Classification. As stated in ASTM C1027-19, it is the “Standard Test Method for Determining Visible Abrasion Resistance of Glazed Ceramic Tile”…
…“The abrasion resistance of tile surfaces is determined by rotation of an abrasive load on the surface and the assessment of the resultant wear by means of visual comparison of the abraded test specimens and non-abraded tiles. A staining agent in light oil may be used to help determine whether abrasion surface is likely to result in mechanical entrapment of dirt particles.”
Tile manufacturers submit samples of tiles to the Porcelain Enamel Institute for testing. The results are typically published in product catalogs and brochures.
PEI Class 0. – WALLS ONLY; Not recommended for floor application.
PEI Class 1. – LIGHT DUTY RESIDENTIAL FLOORS; Rooms receiving bare feet and light foot wear
PEI Class 2. – RESIDENTIAL FLOORS – Residential light duty floors
PEI Class 3. – HEAVY RESIDENTIAL / LIGHT COMMERCIAL – All residential and light commercial floors
PEI Class 4. – COMMERCIAL – All residential and medium duty commercial floors
PEI Class 5. – HEAVY COMMERCIAL; All residential and heavy commercial floors