Fenestration systems as luminaires of varying candlepower distribution

For the purposes of determining their luminous performance, fenestration systems can be considered as luminaires of varying candlepower distribution. In this way, daylighting and electric lighting analyses can be performed simultaneously, in a consistent way. An approach to determine the transmitted distribution through fenestration systems due to radiation from the Sun, sky and ground for their bidirectional transmittance is described. The approach is demonstrated using the experimentally determined bidirectional transmittance of a diffusive sample, to determine candlepower distributions under the uniform overcast, and clear sky luminance distributions.<>