Thermal conductivity “λ”

A measure of the thermal insulation value of a material is the thermal conductivity “λ”. Heat conduction is the transport of heat from particle to particle under a temperature gradient. The thermal conductivity is a measure for the heat conduction in a defined building material at a temperature difference of 1°K (equivalent 1°C).

Measuring thermal conductivity

Figure 03: Measuring thermal conductivity

The thermal resistance R (in m2K/W) of a layer of material is calculated by dividing the thickness of the layer’s, by the thermal conductivity, λ. With a sandwich panel comprising three or more layers, the total thermal resistance is calculated from the total of the thermal resistance figures for the individual layers.