Lighting objectives and demands of future buildings

摘要

The objective of the research was to find out the utility and defects of the present lighting recommendations. One specific aim was to find how the present recommendations take into account the lighting demands of older and partially sighted people. A primary objective of the research was to find out how luminances instead of illuminances could be used as a basis for lighting assessment and lighting recommendations. The application of visual performance in lighting dimensioning was also studied. Experimental measurements were carried out to examine the effects of luminance and light spectrum on visual acuity. Young normally sighted, older people and partially sighted subjects participated in the measurements. The results show that there were no significant changes in visual acuity between luminance levels that are normally used in office environments. For the partially sighted, the enlarging of the target size seems to be much more important than the luminance in order to achieve good visual performance. The light spectrum did not have any significant effects on visual acuity. The present lighting recommendations in Finland are primarily based on the CIE visual performance model. The problem in applying the CIE model in practice has been the complexity of the model. On the basis of the visual acuity measurements, a three-dimensional visual acuity model has been developed which predicts visual acuity on the function of luminance, target contrast and observer age. Compared to visual performance models, the much simpler visual acuity model might be used to evaluate the effects of luminance, contrast and observer age on visual performance