Glare Pollution From Building Facades And Its Effects On The Visual Comfort Of The Surrounding Environment: The Case Of Selected Buildings In Addis Ababa City

Abstract

In recent years, highly reflective materials have been widely used in the building envelope not only for aesthetic reasons but also to reduce energy consumption and improve occupant satisfaction. The use of highly reflective materials in combination with curved building designs can harm the environment. This problem can cause thermal and visual discomfort for drivers, pedestrians, and occupants of nearby buildings, and it can cause vegetation damage. Hence, this study aims to assess the impact of reflected glare from the reflective building facade on the visual comfort of drivers, nearby residents, and pedestrians. For drivers? and nearby residents' visual comfort assessments, a geometrical approach was adapted. For pedestrians' glare assessment the relationship between pedestrians and reflected glare issues is determined by using a survey. For drivers, by using Holladay's veiling glare formula, the veiling glare from the facade of the building was calculated at a different point. For nearby residents, based on the Sydney City Council of buildings standard the reflected glare was assessed in the nearby occupants from the sample building. For drivers, the maximum calculated veiling glare is 413.19 cd/m, 2 which glare is unlikely for drivers' comfort. For nearby residents, according to the standard, the reflected sunlight to the neighboring buildings must not exceed 20% of incident sunlight. However, the reflected sunlight exceeds 47.64% which is greater than the allowable limit so there is reflected glare pollution in the neighborhood buildings occupants. For pedestrians, the subjective assessment was done by using questioner. Building glare significantly affects the glare sensitivity of pedestrians. Age has 35%, glare adaptation has 32 %, glare time has 13 %, and glare duration has a 10 % effect on the glare sensitivity outcome of the pedestrians.