externally reflected component of daylight factor
quotient of that part of the illuminance at a point on a given plane in an interior which is received directly from external reflecting surfaces illuminated directly or indirectly by a sky of assumed or known luminance distribution and the illuminance on a horizontal plane due to an unobstructed hemisphere of this sky, where the contribution of direct sunlight to both illuminances is excluded
Note 2 to entry: The externally reflected component of daylight factor has unit one.
Note 3 to entry: This entry was numbered 845-09-99 in IEC 60050-845:1987.
Note 4 to entry: This entry was numbered 17-422 in CIE S 017:2011.