A study on amenity of indoor illuminations

including the effects of indoor climate

Abstract

This study, consisted of five experiments, was carried out to examine the effects of qualities of interior lighting, especially focused on color temperature of lighting sources, on human amenity (human comfort and pleasantness) by means of physiological measurements as well as psychological evaluations. In the first two experiments, color temperatures of 3000 K, 5000 K and 7500 K were evaluated by electroencephalogram (EEG) as a main measurement. EEG topography in the condition of 7500 K showed decrease in appearance rate of Fmθ and increase in averaged amplitude of β wave on minor hemisphere, which was observed in the room temperature of 25°C . In the second experiment, N 100 and P 300 of event-related potential were observed and combined effects of room temperature and color temperature were revealed. From these observations, it was suggested that higher color temperature tends to cause surplus intensions of cerebral cortex, therefore, which was considered to be unsuitable for amenity. Color temperatures of 3000 K and 7500 K combined with transient change in room temperature from 15°C to 35°C was employed in the third experiment. Changes in systolic blood pressure and thermal sensations among physiological and psychological measurements showed different fashion from the previous findings of studies on color temperature. Fluorescent lamp color condition of red, green and blue was examined in the fourth experiment. θwave band of EEG was increased in the blue condition and decreased in the red one, which seems to reflect some relaxation and intension in the respective color condition. Relationships between population density in a closed space and optimum illumination were investigated in the fifth experiment. It was suggested that required illumination should be enhanced with increasing in population density. Judging from other measurements, it is considered that further studies on optimum color temperature of lighting sources must be performed since it is postulated that effects of color temperature on these circumstances might be more important.