ISO 9050:2026

This document 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 rooms and permit comparison between different types of glazing.

This document applies both to conventional glazing and to absorbing or reflecting solar-control glazing, used as vertical or horizontal glazed apertures. The appropriate formulae for single, double and triple glazing are given. A matrix method is provided as an alternative calculation method.

This document introduces a method to determine the luminous and solar properties of building-integrated photovoltaic (BIPV) glazing.

This document is accordingly applicable to all transparent materials except those which show significant transmission in the wavelength region 5µm to 50µm of ambient temperature 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 (see 5.3).

Angular light and solar properties of glass in building are excluded from this document. However, research work in this area is summarised in References[1], [2] and[3].

Guidance on the measurement of luminous and spectral properties of glass can be found in Reference[4].

Vacuum insulating glass (VIG) is excluded from the scope of this document. For determination of the g value of VIG, refer to ISO19916-1[5].