§ 48-42.   Light 
Habitable spaces. Every habitable space shall have at least one window facing directly to the outdoors or
to a court to permit natural lighting. 
Exception: Where natural light for rooms or spaces without exterior windows or  glazing areas is 
provided through an adjoining room, the unobstructed opening to the adjoining room shall be at 
least 8 percent of the floor area of the interior room or space, but not less than 5 square feet. The 
exterior window area shall be based on the total floor area being served. 
Common halls and stairways. Every common hall, ingress, egress and stairway in residential
occupancies, other than in 1 and  2 family dwellings, shall be lighted at all times with at least a 60 watt
standard incandescent light bulb (or fluorescent equivalent)provided that the spacing between lights shall
not be greater than 30 feet.