BIOLOGICAL EFFECTS OF ARCHITECTURAL LIGHTING AND THEIR ASSOCIATED ENERGY-UTILIZATION

Over the past 13 yrs, a number of studies have documented the effect o f light on physiology, mood, and behavior in humans. However, these st udies have been conducted primarily with portable light devices, such as light boxes or visors mounted near or on the individual. This paper describes a study in which the source of light treatment is built int o the environment, effectively making it part of the architecture. The focus of the paper is both on the integration of the appropriate ligh ting characteristics into the built environment and the preliminary re sults of the biological assessments. Two identical test rooms were con structed, each room lighted by a luminous ceiling controlled by a cent ral dimming system that allowed illuminance levels to be generated fro m 20 through approximately 3200 lx. Subjects were exposed to different light levels through a variety of protocols using these rooms, with d ependent measures of melatonin level and body temperature recorded for each subject under each condition. The data collected through these s tudies provide a clear indication that similar biological effects to t hose observed with portable light devices do exist for built-in archit ectural lighting systems, and that there are significant implications for the future design of lighting systems based upon such results, par ticularly with respect to energy-conservation strategies.