Proposal for an alternative procedure for glare assessment: a new temporal approach of viewing direction

Abstract Glare can be considered as one of the most complex aspects of the daylighting evaluation process due to its subjective nature and the limitations of$ usual forms of assessment. Although the glare is a subjective response, many indices have been developed to quantify this phenomenon. Existing glare assessment models assume that occupants' view direction fixed on the task and ignore the dynamic nature of vision. This paper presents the impact of the time in the calculation of DGI. A teacher was adopted as a dynamic subject who has several view directions. The procedures adopted included the use of a video camera, software for video editing, HDR images and post processing data through photometric measurement system called Photolux. With DGI data for each direction of view, in each position, in all scenarios and the time in which the teacher looked at each direction, estimated through the video, two weights were held: DGItd (time spent in each direction) and DGItp (time spent in each position) resulting in a total index of the room. The results showed that the total index of the room was lower than those values obtained from Photolux in most cases, reaching reductions of up to 30% for a given situation. This study reinforces the importance of incorporating the temporal condition in evaluating glare.