We often hear that the higher the grade of a tile, the higher its quality. Is this true, or only a generalization?
It is important to understand that tile grades are based on a test that determines hardness and durability. The measurement, specifically known as the PEI, characterizes the resistance of the tile surface (porcelain enamel) to scratches. More simply, the PEI determines the resistance of the tile’s enameled surface as compared to the traffic it can handle. The lower the grade, the easier the tile is to damage, since the tile enamel is less resistant; the higher the grade, the more resistant the tile enamel, thus the harder it is to damage.
There are 5 grades that can be classified as follows:
0 to2: Tiles of these grades are mainly intended for decorative purposes, such as wall tiles. Some of these tiles can be installed on the ground; however, only in very lightly trafficked areas.
3: Tiles of this grade are made to resist moderate traffic. These are often the tiles used in residential or light commercial (stores or office space) spaces.
4: Tiles of this grade are intended for medium commercial use and for spaces classified as light industrial, such as restaurant kitchens, because they tolerate higher traffic relatively well.
5: Tiles of this grade are the most resistant to scratches, chemical products and heavy traffic. They are used for shopping centres and airports, where traffic is very dense.
There is also the Mohs scale, which measures the density of mineral material. This classification measures if a tile can be easily marked or scratched by an object. The scale has 10 levels, the first level of which is the least resistant to occasional scratches. The tiles typically used in houses are usually porcelain, which measure from 5 to 8 on this scale.