TILE STANDARDS
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Water Absorption, Breaking Strength, Crazing Resistance, Facial &Thickness Dimensions, Static Coefficient of Friction, MOH’s Scratch Hardness… These are some of the test that our products undergo before being sold, but… What do all these terms and standards mean? How do I know what is best? We, at Porcelanosa Group, know that questions concerning tests are frequently asked and often misunderstood. Let us clarify a number of these questions by explaining some of the rather technical terms associated with tile performance. Throughout this catalog, you will find the results of the rigorous tests that all our products undergo before they are sold in the US. The explanations below should help gain a better understanding of tile performance, thus enabling you to make more informed decisions when it comes to buying tile. Firstly, we should mention that there are two main organizations entrusted with the responsibility for formulating norms and standards applicable to tiles. ANSI (USA) and ISO. (International). The Porcelanosa Group carries out tests dictated by both organizations; being the perfectionists that we are, we make sure that, our tiles not only meet but exceed the minimum requirements set forth by ANSI and ISO. ANSI 137.1 This is the part of the ANSI standards that dictates the tests to be done to ceramic tiles. The results of this testing procedure establish minimum standards for the various types of tile and trims. ISO 13006 “Ceramic Tiles: Definitions, classification, characteristics and marking” establish minimum standards for the various types of tile and trims. ISO 10545 is the part of the ISO standards explaining the standard test methods to be done to ceramic tiles. The following is a brief summary of some of the most significant tests that we conduct on our tiles: Static Coefficient Of Friction ASTM C-1028 describes the standard test method for evaluating the static coefficient of friction, (“COF”) which determines the relative slip resistance of a tile. The higher the COF, the more slip resistant the tile. Please note that any tile or other hard surface flooring can become slippery when wet or improperly maintained. Slip resistance varies with the many types of footwear. Judgment should be used when any hard surface flooring is installed in areas where dampness, water, or inadequate maintenance is likely to be encountered. Also, the static coefficient of friction may vary within and between production runs because of the inherent characteristics of ceramic tile. Breaking Strength ASTM C-648 describes the method for determining structural strength of ceramic tile as related to its ability to withstand installation procedures, such us the hammering process to develop proper bond. The higher the breaking strength, the stronger the tile is. Tiles with higher breaking strengths can usually be expected to withstand impact and breakage better when installed on floors with adhesives. The minimum breaking strength for a floor tile is 250 pounds. Facial And Thickness Dimensions ASTM C-499 This test method covers the determination of the facial dimensions and thickness of flat, rectangular ceramic wall and floor tile. A given number of tiles are measured across the face and in thickness. The results are averaged and the range of dimensions recorded. Water Absorption The percentage of water absorption by the tile body determines whether ceramic tile is impervious, vitreous, semi-vitreous or non-vitreous. ISO 10545-3 describes the standard test method for determining the percentage of water absorbed by the body of a ceramic tile. Results are expressed as a percent of the weight of water absorbed to the weight of dry tile. The following standards apply: - Impervious: water absorption of 0.5% or less - Vitreous: water absorption of more than 0.5% but not more than 3.0% - Semi Vitreous: more than 3.0% but not more than 7.0% - Non-vitreous: more than 7.0% Exterior applications will require an impervious tile whereas for less demanding usage you could select a vitreous or semi-vitreous tile. The body of the wall tiles is normally non-vitreous, thus facilitating the absorption of the adhesive used for installation and improving the bonding strength.
Deep Abrasion Resistance ISO 10545-6 is the standard test for ‘Unglazed’ products. Where glazed material is tested using the PEI method, to ascertain the resistance to abrasion on the glaze, so ‘Unglazed’ products are tested for their resistance to deep abrasions on the surface of the tile. Results are expressed as volume of material removed, in cubic mm, the less volume of material removed, the more resistant the surface. Superficial Abrasion Resistance (PEI Method) Although there are no industry standards, most GLAZED ceramic tiles are rated for use by the Porcelain Enamel Institute (PEI) abrasion test and is recommended by the American Society Testing Materials (ASTM). PEI ratings measure the wear resistance of the tile surface. The test is performed in accordance with the method described in the ISO 10545-7. The test is carried out by exposing the glazed surface to an abrasive procedure, which is created by adding balls of differing diameters, corundum and water. The head of the testing machine is then set to rotate at a fixed speed for a given period of time, abrading the charge against the glazed surface. The number of revolutions to be carried out is entered into the digital electronic pulse counter, with a LED display. Visual inspection of the test piece after the cycle is completed will classify it into the various abrasion groups specified by the method. Class 1 No Foot Traffic: Ceramic tile suggested for interior residential and commercial wall applications only. Class 2 Light Traffic: Ceramic tile suggested for interior residential and commercial wall applications and for residential bathroom floor applications only. Class 3 Light to Moderate Traffic: Ceramic tile suggested for residential floor, countertop, and wall applications. Class 4 Moderate to Heavy Traffic: Ceramic tile suggested for residential, medium commercial and light institutional floor and wall applications. Class 5 Heavy to Extra Heavy Traffic: Ceramic tile suggested for residential, commercial and institutional floor and wall applications subjected to heavy to extra heavy traffic. Mohs’ Hardness Scale This is another example of a test which is not standardized but is widely used among the industry. Scratch resistance of glazes is measured by scratching the glaze with a mineral of known hardness. Hardness of minerals is classified by Moh’s Scale, which lists 10 minerals according to their hardness. Each mineral in this scale will scratch those with lower numbers in the scale, but will not scratch minerals with higher numbers. Talc is classified as number one on the Moh’s Scales and diamond as ten. The Mohs scale was devised by Friedrich Mohs in 1812 and has been a valuable aid to identifying minerals ever since. Here are the ten standard minerals in the scale. 1. Talc 2. Gypsum 3. Calcite
4. Fluorite 5. Apatite 6. Feldspar
7. Quartz 8. Topaz 9. Corundum
10. Diamond
When a tile is classified with one of the numbers on this scale, it means that this particular tile has been scratched with the corresponding mineral bearing thus this number, determining its surface’s hardness. Frost Resistance ISO 10545-12 describes the standard test method for determining ceramic tile’s ability to withstand repeated cycles of freezing and thawing. Frost resistance is a property that can only be required for a wall and floor tiles destined to be used outdoors or for use inside refrigeration chambers. It is extremely important to know where the tile is going to be installed and if needed, the end user must ask for this certification.