scope:

This International Standard sets out the specifications for a three-dimensional and a two-dimensional geometrical model of a thermal bridge for the numerical calculation of: heat flows, in order to assess the overall heat loss from a building or pa rt of it; minimum surface temperatures, in order to assess the risk of surface condensation. These specifications include th e geometrical boundaries and subdivisions of the model, the th ermal boundary conditions, and the thermal values and relation ships to be used. This International Standard is based upon th e following assumptions: all physical properties are independe nt of temperature; there are no heat sources within the buildi ng element. This International Standard can also be used for t he derivation of linear and point thermal transmittances and o f surface temperature factors.