An Examination of Visual Comfort in Transitional Spaces

Abstract

This study investigated the issue of visual comfort at building entrances as the user moves from darker interior spaces to the brighter exterior. The effects on visual comfort of several design features such as overhead trellises, solid overhangs, vertical fins, and solid sidewalls were assessed. These features were tested individually and in various combinations. Visual comfort was expressed in terms of the luminance ratios at equidistant station points along the user's path in the transition entry zone. Discomfort sensations resulting from the difference in luminance ratios according to various design combinations ranged from “dramatic” (high visual discomfort or shock) to “subtle” (little visual discomfort). It was found that several design features significantly affect visual comfort. In particular, a deep canopy with combined transmittance characteristics (partially and entirely blocking daylight penetration) extending over the entrance of the building leads to the greatest visual comfort, but a simple 4.8m overhang was also found to be adequate, leading to reasonable visual comfort.