1 Scope
This document specifies a detailed method, based on spectral data of the transmittance
and reflectance of the constituent materials (solar protection devices and the glazing),
to determine the total solar energy transmittance , the total light 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 louvres, venetian blinds, 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 solar energy absorbed
by the glazing or blind components, for vertical orientation of the glazing.
The blind component materials may be transparent, translucent or opaque, combined
with glazing components with known solar transmittance and reflectance and with known
emissivity for thermal radiation .
The method is based on a normal incidence of radiation and does not take into account
an angular dependence of transmittance or reflectance of the materials. Diffuse irradiation
or radiation diffused by solar protection devices is treated as if it were direct.
Louvres or venetian blinds are treated as homogenous materials by equivalent solar
optical characteristics, which may depend on the angle of the incidence radiation.
The current method is limited to vertical installation ±15°. For situations outside
the scope of this document; ISO 15099 covers a wider range o...