Section R. 400.10407 - LightingRule 407.
(1) Every sleeping room that is occupied by residents shall have natural light from a source which is equal to not less than 8% of the floor area for that room. A skylight, louver, glass-blocked panel, or similar light-transmitting device shall not be counted for more than 50% of the required area in place of conventional windows and glass doors.(2) Every habitable room shall have artificial light that is capable of providing not less than 20 footcandles of illumination at a height of 3 feet above the floor.Mich. Admin. Code R. 400.10407