Facilitation of visual adaptation to glare control for daytime fire evacuation from an office building in Malaysia

Abstract

This paper proposes that the light intensities of adjacent interior spaces should be concurrently evaluated to reduce the risk of glare when evacuees transition between spaces to reach the final exit. The prevention of glare during daytime evacuation has the potential to smoothen the evacuation process from a building. As all legislative, regulatory, and assessment tool recommendations currently used in Malaysia measure illuminance (in lux), this paper similarly evaluates illuminance instead of luminance for ease of initial adoption in the country. Illuminance recommendations in MS1525:2019, LEED, DOSH Guidelines, UBBL, GBI, GreenRE, Melaka Green Seal, and MyCREST were compared to determine the contrast ratio. The illuminance contrast is greatest at the final exit points, such as from parking structures, lobbies, and staircases, which are benchmarked against the Malaysian sky illuminance that can reach 100,000 lux. A contrast ratio as high as 2000:1 may occur if Malaysian offices were designed to only achieve the minimum illuminance requirements. Of the three assessed final exit spaces, naturally-lit fire escape staircases were selected for modelled simulation of illuminance performance using VELUX Daylight Visualiser 2. The findings ascertained that most typical staircase layouts are able to exceed the minimum illuminance requirements at noon, when the sun is potentially the most intense, although the contrast ratio may still reach 1480:1. While the contrast between intermediate spaces are acceptable, those between the final exit transitions and the outdoors are high, suggesting a risk of glare. Further studies are required to determine strategies to facilitate visual adaptation for Malaysians, such as the identification of an ideal acceptable illuminance contrast ratio, temporal adaptation period, or distance-based parameters.