The average interval of thermal conductivity of insulation varies in the range 0.029 – 0.21 W / (m / C). The standard heat is the thermal conductivity of air – 0.025 W / (m / C). Heat index most effective insulation should be as close to the indicator. Learn more at: Discovery Communications. Thermal conductivity of insulation directly depends on ambient temperature. The technical documentation to figure insulant heat is usually at (25 5) C. Thermal conductivity of water is ten times more thermal conductivity of air, so insulation material should always be kept dry.
Water vapor permeability of insulation important property of insulation – its water vapor permeability. The value of this index varies diametrically opposite, depending from the point of use heater. With insulation of external walls (including the roof), toward the interior insulation should be used with a maximum vapor resistance, ie, with minimal indication of permeability. Respectively, toward the exterior, insulation must be applied with a maximum water vapor permeability, ie with the maximum value of permeability. Water vapor permeability of insulation is measured in mg / (m * h * Pa) characterizes the amount of water vapor in mg, which passes through the one-meter thick concrete material for one hour at a pressure difference of 1 Pa. Flammability of insulation (the group of combustibility) Heaters are divided into incombustible (NG) and oil (D). Combustible materials are divided into four groups – T1, T2, T3, T4. For non-combustible construction materials other indicators of fire danger is not defined.