The Influence of Multi-Storey Surrounding Development on a Daylighting of Interiors in Top-Lit Premises: An Experimental Study

To ensure a required daylight in premises with top system of outdoor illumination through roof lighting installations, it is necessary to take into account the photometrical effects of surrounding development. For the time being such a concept in lighting engineering design is adopted only for side lit premises through windows, though the dense urban development in modern megalopolises offers nearly the same problem for buildings with overhead daylighting system. This paper presents a brief description of experimental case studies, based on the scale model method, as well as on the photometric studies of a real premise with skylights. The studies were conducted in both cases under CIE standard overcast sky with changing geometrics and photometrical parameters of model elements. The results of the studies showed the great photometric influence of opposite-standing objects on the values of daylight factor (D) in premises with top lighting system and dependence of this influence on size, position, and structural type of skylights, as well as on size and finishing of the model parts and on distance between skylights and opposite-standing building.