This standard gives methods of calculation of heat transfer coefficients and heat flow rates, for building elements in thermal contact with the ground, including stab-on-ground floors, suspended floors and basements. It applies to building elements, or parts of them, below a horizontal plane in the bounding walls of the building situated - for stab-on-ground floors and suspended floors, at the level of the inside floor surface; - for basements, at the level of the external ground surface.