Sunlight and insolation of building interiors.

Quality of indoor environment can be determined by physical and psychological parameters. Sun radiation access and its vital visual and warm influences are generally required by habitants in interiors. Daylight design of buildings is designed according to minimum illuminance requirements to achieve acceptable visual conditions usually under overcast skies. However, circadian rhythm studies have noticed the importance of higher illuminance levels to stimulate human activities and the proper functions of body organs. Sunlight during a day can offer higher levels of illuminance either directly or by reflection from outdoor and indoor surfaces. There are a lot of indoor spaces permanently occupied by people in various climatic zones in which access to sunlight benefits should be allowed or shaded. Mainly in summer there are workplaces when protection against excessive sunlight causing glare and overheating has to be controlled by sun devices. The survey of criteria for evaluation sunlight provision in buildings across the Europe and basic rules for design of effective insolation of buildings are discussed. (C) 2015 The Authors. Published by Elsevier Ltd.