Performance-driven cleaning frequency of vertical glazing units.
Windows are an essential component of the building envelope and one of their primary functions is to provide building occupants with a visual connection with the outdoors through daylight/sunlight access and views. However, dust deposition can impede upon both of these functions of windows by reducing the quantity of light transmitted and also reducing view clarity. Field studies in urban areas (India, EU, and south-east Asia) have found around 10% loss in transmittance of visible light due to dirt deposition on vertical glazing. Protocols for daylight assessment in buildings call for 5-15% dirt-related depreciation in visible light transmittance of glazing. Dust deposition may also reduce occupants’ satisfaction with the view. In spite of these losses, window cleaning schedules are largely driven by operational costs and maintenance-related norms. In this project, we shall propose performance-driven window cleaning frequency to better inform cleaning practices and achieve a better balance between occupant satisfaction and maintenance costs. This study will also inform our current understanding of the optical properties of soiled glass and its impact on the indoor environment.
