EN 410 and EN 673

EN 410
Specifies methods of determining the luminous and solar characteristics of glazing in buildings. These characteristics can serve as a basis for lighting, heating and cooling calculations of eooms and permit comparison between different types of glazing. This standard applies both to conventional glazing and the absorbing or reflecting solarcontrol glazing, used as vertical or horizontal glazed apertures. The appropriate formulae for single, double and triple glazing are given. This standard is accordingly applicable to all transparent materials except those which show significant transmission in the wavelength region (5 to 50) �m of ambient temterature radiation, such as certain plastic materials. Materials with light-scattering properties for incident radiation are dealt with as conventional transparent materials subject to certain conditions.

EN 673
Specifies a calculation method to determine the thermal transmittance of glazing with flat and parallel surfaces. This standard applies to uncoated glass (including glass with structured surfaces, e.g. patterned glass), coated glass and materials not transparent in the far infrared which is the case for soda lime glass products (called hereafter soda lime glass), borosilicate glass and glass ceramic. It applies also to multiple glazing comprising such glasses and/or materials.