2009 - Daylight Symposium
DAYLIGHTING LEGISLATION AND HEALTH by Mohamed Boubekri
PhD, Associate Professor
Practice and Technology Faculty, School of Architecture, University of Illinois at Urbana-Champaign
Over the last three or four decades, discussion about daylighting as a viable architectural design option has been linked to the debate about energy conservation in architecture. Daylight in general, and sunlight in particular, are vital to life on earth, and it is not difficult to believe that their absence fosters conditions that promote disease. Through photosynthesis and other processes, sunlight provides photochemical ingredients necessary for our lives. There are fundamental biological, hormonal, and physiological functions coordinated by cycles that are crucial to human life. A 1998 World Health Organization report (1998) noted that up to 30% of new and remodeled buildings worldwide may be linked to health problems. The effects of poorly designed buildings, whether in terms of limited access to sunlight or poor indoor air quality, continue to affect the health of building occupants. Tall buildings eclipse streets, limiting the movement of fresh air, eroding the immediate connection between ourselves and the natural environment. There are serious health effects due to lack of exposure to sunlight. Lack of sunlight exposure causes serious vitamin D deficiencies, which in turn cause of range of health issues such as osteomalacia and bone frailty, internal cancers, seasonal and normal depression among others.
As people spend increasingly more time indoors due to work reasons, the issue of the lack of daylight and its impact on the health of building occupants becomes ever more salient. Yet building codes and lighting standards are still inadequate in dealing with the issue of daylighting. Increased urbanization since the turn of the 20th century has led to the erection of concrete, glass, and steel skyscrapers. A review of daylighting standards worldwide shows that the so called daylighting standards prescribe either a certain window or at the very best a daylight factor. Daylight factor prescriptions tend to be mere recommendations. No obligatory requirements for daylighting in fact exist. Most countries require windows for building. Legislation based on window size may be only incidental to daylighting as generally no requirements for window controls, shading, etc. In order for daylighting legislation to be effective, prescriptions based not only on daylight factors should be required, but also duration of daylight penetration.
Mohamed Boubekri, PhD, Associate Professor, Practice and Technology Faculty, School of Architecture, University of Illinois at Urbana-Champaign.