PEI ratings PEI rates abrasive resistance of the tile's glaze on a scale of 0-5. This test is only for glazed tiles and does not apply to unglazed porcelain tile or other unglazed types of tile. Deep abrasion test for through body porcelain tile.
PEI ratings of glazed tile
Class 0. Suitable for walls only
Class 1. Recommended for wall use
But may be used both on interior walls or bath floors without direct access to outdoor elements.
Class 2. Suitable for most residential floors
May be used where abrasive foot traffic is minimal - such as bathrooms, bedrooms, dining rooms, living rooms, and sunrooms.
Class 3. Ideal for all residential floors
For floors subject to normal foot traffic and usage (including kitchens, outdoor entryways and hallways).
Class 4. Great for all residential and light-medium commercial
Suitable for light to medium commercial applications. Will withstand moderate foot traffic in many commercial areas (commercial kitchens, hotel rooms, exhibition halls, etc).
Class 5. Great for all residential and most commercial
Ideally suited for all residential and most commercial applications under normal foot traffic conditions (shopping centers, hotel foyers, walkways, and industrial applications). For very high traffic areas, consider and unglazed through-body color porcelain, which does not carry a PEI rating.
Frederick Mohs invented this geological scale of minerals to rate scratch resistance from 1-10. Think of Mohs as Method Of Hardness Scale. This test is not an industry standard but it's a great comparison to show the difference in scratch resistance between tile and other hard flooring materials.
Coefficient of friction (COF)
The coefficient of friction rates the slip resistance of a tile. ADA recommends a test rating of .6 (wet or dry) on floors and .8 for ramps. However, common sense must prevail. If you are told that a shiny surface tile has a .6 rating, stop and think if that tile really will be slip resistant.
The breaking strength test is a good indicator of the chip resistance of a tile because it tests the strength and density of the bisque. Using applicable ASTM test, ceramic floor tile typically has a breaking strength of 250 lbs. This can be less for poor quality tiles, higher with porcelain tiles (up to 400lbs).
What do you want your tile to do?
Facial surface. A slip resistant surface may be more difficult to keep clean. A glossy surface may show dust and be slick.
Body strength. Chip resistance, frost resistance, breaking strength, and water resistance. Make sure that the tile face and the tile body meets both performance and visual expectations.
TRAVERTINE QUALITY RATINGS
Travertine is divided into four visual classifications. As with other natural stone products such as diamonds and precious stones, the value of travertine is based on the visual appeal, availability and rare qualities of the stone. As these are visual based categories, the durability or suitableness for a specific purpose are not part of this classification.
Tiles with a commercial rating are divided into two distinct categories.
Class “A” is for appearance. The distinctive variation that occurs in an “A”. quality commercial stone may include a broad color range, a unique color range, usual mineral deposits or a moderate amount and size of fill. Class “A” commercial tiles will be of uniform thickness, squareness and size, but may have some variation in finish and fill color.
Class “B” is for dimension. Travertine tiles in this category may have variations in size or thickness, a considerable amount of fill or very large fill. These tiles are usually set with a 3/16” or larger grout joint.
Classic Quality A classic quality tile will be of a consistent size as to allow a grout joint of 1/8” or less. Classic tiles will have a moderate amount and size of fill. Classic tiles are sorted within a defined color range with minimal mineral deposits.
First quality travertine tiles are sorted to have minimal fill and color variations within a defined range. First quality tiles have virtually no unusual mineral deposits and they are precision sized for minimal grout joints and ease of installation.
Premium quality travertine is so designated because of the unusually high density of the stone. This means that there are very few and very small holes. The face of a premium quality stone will be of discernable higher visual quality when placed next to other qualities of travertine