This International Standard provides the method of calculation of the thermal resistance and thermaltransmittance of building components and building elements, excluding doors, windows and other glazed units, curtain walling, components which involve heat transfer to the ground, and components through which air is designed to permeate.The calculation method is based on the appropriate design thermal conductivities or design thermalresistances of the materials and products for the application concerned.The method applies to components and elements consisting of thermally homogeneous layers (which can include air layers).This International Standard also provi