Assessing daylight luminance values and daylight glare probability in scale models: Fid-Bau Portal

Assessing daylight luminance values and daylight glare probability in scale models

Bodart, M. / Cauwerts, C.

AbstractThis paper presents a research about the possibility to use a scale model of a room to assess the luminances in the visual field of the room's user, and consequently its risk of glare.Measurements of luminance values by the HDR technique were done simultaneously in a room and its 1/6 scale model, with identical measurement material. The room was lit by a lateral window either unprotected from direct sun radiation, or fitted with a white or black screen.Measurements show that luminance values obtained in the scale model are overestimated and that the relative differences between values in the scale model and in the mock-up vary between 10 and 50% for the situation without shading device, between 45 and 80% for the window equipped with the white screen and between 0 and 45% with the black screen.Yet, the evolution of luminances is very similar for both rooms, and a high level of correlation is observed between glare index DGP values calculated on these respective luminance values, despite a very slight over-evaluation of the DGP in the scale model.In conclusion, for the situation tested, the DGP can be evaluated using a 1:6 scale model, under the condition of very accurately respecting the geometry and photometric data of the studied room walls. It is also very important to position the scale model in a way to obtain a view on the outside as similar as possible to the one obtained from the studied room.

Highlights•Comparison of luminance values and DGP measured in a room and its 1/6 scale-model.•High overestimation of luminance values in the scale-model.•Low overestimation of DGP in the scale model and high correlation.•A 1/6 scale-model can be used to evaluate DGP.•These results should be validated for other geometrical cases.