(A) Provide for natural light and ventilation in all habitable rooms.
(1) The area of glazed portions of doors in outside walls may be included in the calculation of natural light requirement.
(2) The glass area required to provide the minimum natural light in a habitable room shall be equal to 8% of the floor area of the room.
(3) The area required to provide the minimum natural ventilation in a habitable room shall be openings to the outside equal to 4% of the floor area of the room.
(4) The floor area of two habitable rooms not separately lighted or ventilated, may be combined in computing required light and ventilation. The wall separating such rooms, however, shall contain an opening not smaller than 60% of the wall area.
(5) Every sleeping room shall have at least one operable window or exterior door approved for emergency egress or rescue. The units must be operable from the inside, opening without the use of tools. Where windows are provided, they shall have a sill height not more than three feet six inches above the floor. Escape windows from sleeping rooms shall have a minimum clear opening of six square feet. The minimum clear opening height dimension shall be 24 inches. The minimum clear opening width dimension shall be 20 inches.
(B) Provide for light and ventilation in water closet compartments, utility rooms, powder rooms and bathrooms by one of the following means:
(1) Provide a window or skylight in an exterior wall or ceiling with a light and ventilation area of 4% of the floor area, but not less than three square feet;
(2) Provide a vent in or near the ceiling with a continuous duct to the outside or to a ventilated attic. Such mechanical exhaust systems shall be provided with a damper and the fan shall be capable of moving two cubic feet of air per minute for each square foot of floor area; or
(3) Ventilation shall be installed to provide combustion air in accordance with the International Mechanical Code, 2003 Edition, International Code Council, Inc. (see § 150.020), for fuel burning appliances in confined rooms or spaces where natural ventilation is not provided.
(C) Provide for light and ventilation in basements and crawl spaces.
(1) Provide doors or windows in exterior walls of basements. The total glazed and ventilating area of which shall be not less than one-fiftieth of the gross floor area of the basement.
(2) Crawl spaces shall be ventilated to the outside or through access openings to the basement. The ventilator or access area shall be no less than one-third square foot for each 100 square feet of crawl space area. Adjustable vents to the outside shall be provided with corrosion resistive insect proof wire mesh screen and be operable from the exterior. Inaccessible or unventilated crawl spaces shall not be permitted.
(D) Provide for ventilation in all attic and roof spaces at the rate of one-third square feet for each 100 square feet of the ceiling below.
(1) Ventilator openings shall be screened.
(2) Blocking, bridging and insulation shall be arranged in flat roof and vaulted ceiling areas so that it will not interfere with the free movement of air.
(3) Ventilation installed in accordance with the graphic illustration in § 150.208 shall be considered satisfactory compliance with this section.
(Prior Code, § 9-97) (Ord. 94-11B, passed 4-21-1994)