Passive intervention for optimising day-lighting in a selected reading room of the Department of Architecture, Ahmadu Bello University, Zaria

Visual discomfort is one of the main triggers for making reading an uncomfortable exercise. Even though daylight is an abundant commodity in the tropics, the abundance of this within spatially deep planned areas hampers the efficacy of conventional windows in reading rooms to allow for visual comfort. This study assesses the fenestration type and material use in a selected reading room in the department. The room was selected based on its position with respect to other reading areas. The readings are observed and recorded with a light meter and were compared with simulated readings of the same room with a view to recommending suitable retrofitting of fenestration and light devices so as to optimise illumination whilst having minimum discomfort from glare etc. Simulations show that there can be a significant increase in illumination with the change in fenestration type. The data room of the Department of Architecture which doubles up as a library for the department, is taken as a case study to see how passive lighting techniques can be used to improve visual comfort in the chosen area. It is discovered that the windows on the southern side are prone to allowing excessive light into the room, thereby causing a problem of glare. Readers on that side of the room were only able to use that section of the library satisfactorily at certain parts of the day. Computer simulations indicate that there is sufficient illumination all through the study area with 70% of the study area having illumination values of a minimum of 100 lux and up to 2000 lux. This indicates a level of illumination that is sufficient and thus does not require artificial lighting. Visual discomfort such as glare can be reduced through the retrofitting of horizontal shading devices which will aid in curbing excess light.