Occupants' Visual Sensitivity According to the Illuminance Fluctuations of the Office Space

From the perspective of a lighting user, changes in illuminance can be recognized and visual fatigue increases as the range of change increases while visual satisfaction decreases. In this study, when the indoor illuminance level was controlled with four set illuminance levels of 300lx, 400lx, 500lx, and 700lx, the visual comfort of lighting users was analyzed as it relates to the measured illuminance value, illuminance preference, eye fatigue, and sensibility based on the brightness questionnaire. Visual sensitivity was derived from the change in the perceived brightness response of a lighting user according to the change in illuminance. As a result of the visual comfort analysis, the illuminance preference desired by occupants differed according to the set illuminance. The lower the setting illuminance, the clearer the tendency to prefer bright illuminance. There was a difference in the degree of eye fatigue affected by various factors. In the case of perceived brightness, it was investigated that as the set illuminance was higher, the perceived brightness at the same overall illuminance was relatively dark. In the case of the set illuminance 700lx, it was found that the illuminance was intuitively perceived as bright. As a result of the occupant's sensitivity analysis according to the change in illuminance, it revealed an illuminance change of 74.9lx (300lx), illuminance change of 63lx (400lx), illuminance change of 111.7lx (500lx), and illuminance change of 51.2lx (700lx). In this case, it was found that the lighting user could visually perceive the change in brightness for the first time. As a result of deriving visual sensitivity through regression analysis, it revealed that the higher the setting illuminance, the lower the visual sensitivity.