Mascoutah — Ch. 29 Art. III Environmental Requirements (Property Maintenance) § 29-3-36

All spaces or rooms shall be provided sufficient natural or artificial light so as not to endanger health and safety. (a)
Habitable spaces. Every habitable space shall have at least one window of approved size facing directly to the outdoors or to a court. The minimum total window area, measured between stops, for every habitable space shall be eight percent of the floor area of such room, except in kitchen when artificial light is provided in accordance with the provisions of the Building Code listed in appendix A. Whenever walls or other portions of a structure face a window of any room and such obstructions are located less than three feet (914 mm) from the window and extend to a level above that of the ceiling of the room, such a window shall not be deemed to face directly to the outdoors not to a court and shall not be included as contributing to the required minimum total window area for the room.
(b) Common halls and stairways. Every common hall and stairway in every building, other than one and two family dwellings, shall be adequately lighted at all times with an illumination of at least a 60-watt standard incandescent light bulb or equivalent for each 200 square feet (18.60 m 2 ) of floor area, provided that the spacing between lights shall not be greater than 30 feet (9144 mm). Every exterior stairway shall be illuminated with a minimum of one foot candle (10.76 lux) at floors, landings and treads.
(c) Other spaces. All other spaces shall be provided with natural or artificial light of sufficient intensity and so distributed as to permit the maintenance of sanitary conditions, and the safe use of the space and the appliances, equipment and fixtures.