Assessment of discomfort glare in daylit rooms with shading devices : results from a field study and comparison with software simulation

Some of the critical factors affecting the visual comfort level in daylit spaces include glare, window luminance and luminance contrasts within the field of view (FOV). As far as daylight glare is concerned a new glare prediction model (Daylight lare Probability DGP), based on the determination of the percentage of annoyed people, has been recently propose by Wienold and Christoffersen. The research activity presented in this paper is based on the application of this new approach to assess the impact of different solar shading devices on daylighting quality by using field measurements. In addition to the field campaign, the luminous environment determined by the presence of solar shading devices was also simulated with Radiance, with the aim of comparing the field measured DGP values to the ones obtained through computer simulations. The paper presents some first results of the study that is still in progress