Planning & Zoning staff shall place a limitation on the on-site horizontal average illuminance for all projects, and the perimeter vertical illuminance when the site is within 150 feet of a residential property line. On-site illuminance shall be based upon a “maintained” average horizontal value at finished grade, and the perimeter illuminance shall be based upon an “initial” maximum vertical value at 6 feet above finished grade. These illuminance limitations shall be different for each lighting “zone”. The Light Loss Factor for all “initial” illuminance calculations shall be no less than 0.95. The Light Loss Factor for all “maintained” calculations shall be determined by the designer, and based upon the actual lamps selected and the projected operating conditions, to the satisfaction of Planning & Zoning staff.