The quality and value of the cladding directly depend on the symmetry and uniformity of its individual components, i.e. individual tiles in relation to the quality of the surface and its dimensions. That is why, any dimensional differences and asymmetries of the tiles, deviations of the surface from flatness, which violate the harmony of the cladding and worsen its appearance, will be considered defects. The quality of the surface is determined by the presence of the following defects: gaps, cracks, lack of glaze, unevenness, depressions, pits, damage to the vitrified surface, specks and stains, body defects, decorative defects, darkening, chipped edges and corners.
If defective tiles do not exceed 5%, then the batch is assigned FIRST GRADE, and if they exceed 5%, then the batch is assigned SECOND GRADE.
The appearance characteristics, as well as the dimensional characteristics, are checked randomly on the tiles before they are packaged. Control is carried out visually by specially trained personnel (MANUAL SORTING) or by machine (AUTOMATIC SORTING).
The following type characteristics are important: length of the sides and thickness, straightness of the sides, orthogonality, flatness of the surface.
The difference in size and dimensional deviations are expressed as a percentage of the working size of the tile.
The method for controlling size and appearance characteristics is described in EN ISO 10545-2. To control the appearance, a minimum of 30 samples of tiles are selected, which must form a surface area of at least 1 m². The appearance of the tiles is checked visually (with the naked eye) at an illumination of 300 lux from a distance of 1 m from the observer’s eyes. According to the standard, preparation of the sample surface and visual assessment of the surface are carried out by different persons. Surface quality is expressed as a percentage of the number of tiles without defects.
Information on this issue is presented in the article Dimensional and type characteristics .
Thermal conductivity is the ability of material bodies to transfer energy (heat exchange) from more heated parts of the body to less heated parts of the body, carried out by chaotically moving particles of the body (atoms, molecules, electrons, etc.). Such heat exchange can occur in any body with a non-uniform temperature distribution, but the mechanism of heat transfer will depend on the state of aggregation of the substance. Porcelain stoneware, due to its dense, almost non-porous structure, is distinguished by relatively high thermal conductivity.
Porcelain stoneware, due to its dense, almost non-porous structure, has a relatively high thermal conductivity, which is higher than that of some other flooring materials (for example, natural stones such as marble or granite).
The thermal conductivity of ceramic tiles usually varies from 0.5 to 1.1 W/(m °C); lower values apply to porous materials (single and double fired tiles, monoporosity).
The method for determining the thermal conductivity of ceramic tiles is given in ISO 10545-03. The essence of the method is that in steady state, the energy flux density transmitted through thermal conductivity is proportional to the temperature gradient.
The thermal conductivity of the flooring material becomes particularly important when the choice is made in favor of heated floors (warm screed). Here, naturally, porcelain stoneware with its high thermal conductivity has no competitors.
The thermal conductivity of ceramic tiles usually varies from 0.5 to 0.9 kcal/(m h °C); lower values apply to porous materials (single and double fired tiles, monoporosity).
The SI unit for thermal conductivity is W/(m K).
Information on this issue is presented in the article Thermal conductivity .
Slip resistance is determined by the kinetic and dynamic conditions of motion of the body interacting with the surface. When it comes to flooring, it is obvious how the degree of slip is related to the safety of using the surface. Knowledge of surface properties is essential for the cladding designer, tiler, retailer and end user, as well as the safety inspector. Please mark the correct conclusions in your opinion:
Ceramic tiles, characterized by their smoothness and shine, form the most intimate contact between the surface and the sole, thereby increasing the coefficient of friction. While rough, uneven surfaces tend to allow water or other liquids to accumulate on them, as well as dirt, grease and other substances that act as lubricants. In addition, the area of contact with the sole, in this case, is limited by the protruding edges of the surface, which also reduces slip resistance. This factor must be taken into account when choosing tiles.
According to the DIN 51130 method, floors in production facilities or work areas where there is a high risk of slipping are classified into the following groups (according to the average inclination angle): NC; R9; R10; R11; R12; R13. Where R13 is the slipperiest tile.
According to the DIN 51097 method, in rooms where floors are often wet and where people walk on them barefoot (for example, swimming pool sides, children's pools, common shower rooms, saunas, etc.), the classification contains groups: A; B (A+B); C (A+B+C). Where A is the slipperiest tile.
The DIN 51130 and DIN 51097 methods, also called "incline plane methods", consist of a person walking back and forth on a platform covered with the tiles being tested. The inclination of the test section increases at a constant rate until an angle is reached at which the person begins to feel unsure when walking, that is, begins to slide.
Friction coefficient is a parameter characterizing the degree of surface sliding. It is proportional to the force parallel to the interaction surface that must be applied in order to create relative motion between two bodies. The higher its characteristics such as smoothness and shine, the lower the coefficient of friction for floor surfaces, since this contributes to the appearance of a thin, continuous layer of water (as well as grease, dirt, etc.), which acts as a lubricant between the sole and the floor. Ceramic tiles, while smooth and shiny, create a slippery surface and increase the risk of falls and accidents.
Material on this issue is presented in the article Slip resistance on dry and wet surfaces .
Abrasion resistance is a mechanical characteristic of a lined surface. Indicates the surface’s resistance to wear due to exposure to rubbing objects, surfaces, and materials. Which expressions do you think are correct?
The wear resistance requirements for unglazed ceramic tiles and slabs are set by EN 14411 and depend on water absorption and the method of their manufacture.
Abrasion resistance is a property characteristic only of glazed ceramic tiles. Since intense and prolonged exposure to the surface over time can lead to partial loss of the glazed layer, and this, in turn, will lead to exposure of the ceramic mass and, as a consequence, to the loss of not only the aesthetic, but also the functional qualities of the facing surface. Damage to unglazed tiles is almost invisible, since abrasion of the top layer leads to exposure of the ceramic mass, which in unglazed tiles is no different from the top layer.
Abrasion resistance also affects other functional characteristics of the ceramic tile surface, such as chemical and stain resistance and ease of maintenance. Naturally, this aspect is equally important for glazed and unglazed tiles, because... abrasion leads to a weakening of the tile structure itself, the appearance of pores and microcracks invisible to the naked eye, into which dirt, etc. gets clogged.
According to the test method EN ISO 10545-7:1998, glazed tiles are divided into wear resistance classes, from "0" to "5". Where fifth class tiles are least resistant to abrasion.
The important point is that unlike other quality tests on tiles, durability testing does not determine the value of the tile. The results of the study divide the tiles into classes, each of which corresponds to a specific purpose of the tile, and in no way to divide the tiles into “bad” and “good”.
Information on this issue is presented in the article Abrasion resistance, wear resistance .
Water absorption is a parameter that determines the porosity of ceramic tiles. It is measured by the amount of water that ceramic tiles absorb under certain laboratory conditions, and is expressed as a percentage of the dry weight of the tiles.
Mark the true statements.
According to the EN 14411 standard, ceramic tiles and slabs are divided into three main groups based on water absorption. Where the third group corresponds to the lowest water absorption rates.
The lower the degree of water absorption, the more resistant the tile will be to intense mechanical and hydrothermal influences.
According to EN ISO 10545-3, the penetration of water into the open pores of samples is determined exclusively using the water saturation method in a vacuum. The boiling method, as a test that does not allow determining open porosity and bulk density, is considered obsolete.
According to EN ISO 10545-3, the penetration of water into the open pores of samples is determined using two methods: boiling and water saturation in a vacuum. When boiling, water saturation occurs only in easily filled open pores; with the vacuum method, almost all open pores are filled.
A low water absorption coefficient indicates that the structure of the tile is porous, and a high coefficient indicates that the structure of the material is more dense.
Material on this issue is presented in the article Water absorption .
