(A) Natural light and ventilation. All habitable rooms within a dwelling unit shall be provided with natural light by means of exterior glazed openings with an area not less than 8% of the floor area of the rooms with a minimum of eight square feet. Ventilation shall be provided by openable exterior openings with an area of 4% of the floor area, with a minimum of four square feet. Bathroom, water closet rooms and similar rooms shall be provided with natural ventilation by means of possible exterior openings with an area not less than 4% of the floor area of the rooms with a minimum of one and one-half square feet.
(B) Source of light and ventilation.
(1) Required exterior openings for natural light and ventilation shall open directly onto a street or alley or a yard or court or onto a roofed porch located on the same lot as the building.
(2) For the purpose of determining light and ventilation requirements, any room may be considered as a portion of an adjoining room when one half of the area of the common wall is open and unobstructed and provides an opening of not less than one-tenth of the floor area of the interior room or 25 square feet, whichever is greater.
(C) Mechanical ventilation. In lieu of required exterior openings for natural ventilation, a mechanical ventilation system may be provided. In bathrooms, water closet compartments and similar rooms without required natural ventilation, a mechanical ventilation system shall be provided which is capable of providing five air changes per hour.
(Ord. 253, passed 10-5-2005)