CEN/TC 89/WG 2 - Thermal transmittance

This standard gives design data in tabulated form for heat and moisture transfer calculation, for thermally homogeneous materials and products commonly used in building construction. It also gives data to enable the calculation and conversion of design thermal values for various environmental conditions.

This document specifies the procedures for determining the declared and design thermal values of building products. It is a Bh-type horizontal standard in support of the standardization of building products as performed by the product related CEN/TCs.

This standard gives the method of calculation of the thermal resistance and thermal transmittance of building components and building elements, excluding doors, windows and other glazed units, components which involve heat transfer tothe ground, and components through which air is designed to permeate. The calculation method is based on the appropriate design thermal conductivities or design thermal resistances of the materials and products involved. The method applies to components and elements consisting of thermally homogeneous layers (which can include air layers).