The thermal conductivity of mineral wool products is composed of three components: the thermal conductivity of fibers thermal conductivity of air and moisture, are between the fibers, as well as the transfer of heat by radiation. Thermal conductivity of a solid foundation as a major component of the total thermal conductivity depends on the geometry and fiber orientation in space. For a given density of the most effective thermal insulator is mineral wool with randomly distributed and randomly oriented fibers. Fiber orientation affects not only on the thermal conductivity, but also on the strength properties of mineral wool products. Compressive strength from them increases with the number of vertically oriented fibers.
Thus, the higher the percentage vertically oriented fibers, the lower the density of the mineral slab can be used to satisfy the desired compressive strength. Therefore, mineral wool molding technology to ensure high percentage of vertically oriented fibers are the most progressive. An important property of mineral materials – a negligible shrinkage (including heat), and the preservation of their geometrical dimensions for the entire period of the building. Mineral wool has a very low hygroscopicity: the moisture content in the products from it under normal operating conditions is 0.5% by volume. However, storage at construction site and installation of insulation often occur in wet conditions (eg, rain). To minimize the absorption of water, mineral wool, usually impregnated with a special water-repellent compounds (silicon-organic compounds or special oils). Insulating materials made of mineral wool are highly chemical resistant. Moreover, the mineral wool is chemically passive environment and does not cause corrosion of metals in contact with it.