Specifies Methods of determining light and energy transmission of solar radiation for glazing units in buildings. These characteristics can serve as a basis for light, heating and ventilation calculations of rooms. Applies both to conventional glazing units and to absorbing or reflecting solar-control glazing units. The appropriate formulae for single, double and triple glazing units are given. Applies to all transparent materials except those which show significant transmission in the wavelength region of ambient temperature radiation, such as certain plastic sheets.