EXAMINATION OF THE VALIDITY OF VARIOUS BRIGHTNESS INDEXES BASED ON THE BRIGHTNESS RATING IN THE ROOM WHICH HAS A SCENE THROUGH THE WINDOW

It is shown that the kind of the scene through the window and its brightness influence occupant's rating related to the brightness in the rooms. The relationship between combinations of the various lighting design indexes used for the utilization of daylight and the brightness of the room are found out by the subjective experiment with scale model. The model of the room has a window. The scene through it is composed by the sky, a building and trees. Brightness of the interior, brightness of the exterior, the balance of them and the balance of interior brightness are rated by subject. The lighting design indexes, such as illuminance at the front of face, average luminance of interior and exterior, and the ratio of them, couldn't explain the ratings of the room. It is not suitable, like the present, to make the sum of the illuminances by the daylight and artificial light the design index of the lighting environment.