daylight factor


A measure of daylight illuminance at a point on a plane, expressed as the ratio of the illuminance at that point to the simultaneous exterior illuminance on a horizontal plane from an unobstructed sky of assumed or known luminance distribution (typically overcast). Direct sunlight is excluded from both interior and exterior illuminance values.

NOTE: This definition was changed in RP-16-17 Addendum 2. 

« Back to Definitions Index