The article describes the methods of contemporary daylight factor’ (D.F.) design either with top or side natural lighting systems in buildings. The different methods of design, with different design formulas are based on preliminary determination of the type of lighting system used. But this division is rather conditional and not accurate. Sometimes the source of natural light (say, a window in a wall), which traditionally is judged as a source of a side light, is placed higher, than a monitor or skylight on a roof, which usually are determined as a sources of a top light. The same situation can be seen in determination of an angle of observation of a sky vault portion, observed from a design point within the premise considered. Thus, taking into account the above mentioned statements, one can assume, that with no strict division of external natural illumination under the overcast sky conditions, adopted as a basic theory in contemporary domestic «Codes and Regulations on Natural Lighting of Interiors», it is necessary to offer an universal design formula. This one should be based on standard formulas with respect to specific points, typical either to elements of window, monitor or skylight structures.
Natural light design in premises with roof natural lighting system with consideration of lighting effects of the surrounding housing
