General. Natural ventilation of an occupied space shall be through windows, doors, louvers or other natural openings to the outdoor air.
Ventilation area required. The minimum openable area to the outdoors shall be 4 percent of the floor area being ventilated.
Borrowed ventilation for remote rooms. Where rooms and spaces without openings to the outdoors are ventilated through an adjoining room, the opening to the adjoining room shall be unobstructed and shall have an area not less than 8 percent of the floor area of the interior room or space, but not less than 25 square feet (2.3m2). The minimum openable area to the outdoors shall be based on the total floor area being ventilated.
Ventilation through area wells. Where openings below grade provide required natural ventilation, the outside horizontal clear space measured perpendicular to the opening shall be at least equal to or larger than the depth of the opening. The depth of the opening shall be measured from the average adjoining ground level to the bottom of the opening.
Openings onto yards or courts. Where natural ventilation is to be provided by openings onto yards or courts, such openings shall comply with the requirements of Section 15-8-110 of the Municipal Code of Chicago.
(Added Coun. J. 4-29-98, p. 66679, § 1)