This standard specifies a detailed method, based on the spectral transmission data of the materials comprising the solar protection devices and the glazing, to determine the total solar energy transmittance and other relevant solar-optical data of the combination. If spectral data are not available the methodology can be adapted to use integrated data. The method is valid for all types of solar protection devices parallel to the glazing such as louvre, venetian or roller blinds. The blind may be located internally, externally, or enclosed between the panes of the glazing. Ventilation of the blind is allowed for in each of these positions in determining the distribution of solar energy absorbed by the glazing or blind components. The blind component materials may be transparent, translucent or opaque, combined with glazing components with known solar transmittances and reflectances and with known emissivities for thermal radiation. The standard also gives certain normalised situations, additional assumptions and necessary boundary conditions.