13-172-020 Buildings on same lot.

   Where more than one building is hereafter placed on a lot, or where a building is placed on the same lot with existing buildings and the several buildings are treated as a single structure for the purposes of this chapter, adequate sources of light and ventilation shall be provided for all occupied buildings.

(Added Coun. J. 4-29-98, p. 66679, § 1)

13-172-030 Definitions.

   The following words and terms shall, for the purposes of this chapter, have the meanings shown herein:

   “Attic” means the space between the ceiling beams of the top story and the roof rafters.

   “Court” means an open, uncovered and unoccupied space on the same lot as a building where such space is enclosed wholly or partly by buildings, walls or other enclosing devices (see Section 13-172-130).

   “Court, Inner” means any court enclosed wholly by buildings, walls or other enclosing devices.

   “Court, Outer” means a court extending to and opening upon a street, public alley or other approved open space that is not less than 15 feet (4,572 mm) wide, or upon a required yard.

   “Court height” means the vertical distance from the lowest level of the court to the mean height of the top of the enclosing walls.

   “Court width” means, as applied to an inner court, the least horizontal dimension; and, as applied to an outer court, means the shortest horizontal dimension measured in a direction substantially parallel with the principal open end of such court.

   “Habitable space or room” has the meaning ascribed to the term “habitable room” in Section 13-4-010.

   “Irregular or gore-shaped court and yard” means either a triangular (gore-shaped) or irregular air space surrounded by parts of a building on 2 or more sides and occurring either at grade or at an upper story.

   “Multi-purpose room” means a room within a family dwelling unit which may be used as a study, office, multimedia room or other function normally associated with family dwelling occupancy, and which room is in excess of the essential family needs for living, dining and sleeping outlined in Section 13-172-060(c). Multi-purpose rooms shall not be used as bedrooms.

   “Occupiable space” means a room or enclosed space other than in a family dwelling unit, designed for human occupancy in which individuals congregate for amusement, educational or similar purposes, or in which occupants are engaged at labor; and which is equipped with means of egress and light and ventilation facilities meeting the building provisions of this Code.

   “Vapor retarder” means a material having a perm rating of 1.0 or less, such as foil, plastic sheeting or insulation facing, installed to retard the passage of water vapor or moisture through the exterior envelope.

   “Ventilation” means the natural or mechanical process of supplying conditioned or unconditioned air to, or removing such air from, any space.

   “Yard” means an unoccupied open space other than a court (see Sections 13-172-130 and 13-172-140).

(Added Coun. J. 4-29-98, p. 66679, § 1; Amend Coun. J. 9-14-16, p. 31143, § 3; Amend Coun. J. 11-9-16, p. 36266, § 26*)

* Editor's note – The amendment of Coun. J. 11-9-16, p. 36266, § 26 to this section did not take into account the amendment of Coun. J. 9-14-16, p. 31143, § 3, which renders the later amendment unnecessary.

13-172-060 Light and ventilation required.

   (a)   Light required. Every room or space intended for human occupancy shall be provided either natural or artificial light; provided however that all living, dining and sleeping rooms in family dwelling units; all patient rooms in institutional units; all guest rooms in hotels and motels; all day care centers offering care for children under 2 years of age; all class rooms or study rooms in Type 1 and Type 3 schools; and all habitable rooms in residential restrained care facilities shall be provided with natural light.

   (b)   Ventilation required. Every room or space intended for human occupancy shall be provided with natural or mechanical ventilation; provided, however that living, dining and sleeping rooms in family dwelling units shall be provided with natural ventilation. Natural ventilation shall not be substituted for mechanical ventilation in rooms or spaces where mechanical ventilation is specifically required in Chapter 18-13 or Chapter 18-28 of this Code.

   (c)   Multi-purpose room exemption. Notwithstanding paragraphs (a) and (b) of this section, certain rooms in single-family and multi-family dwelling units in existing buildings constructed pursuant to a permit issued prior to April 1, 1998 may be considered multi-purpose rooms, and such rooms may be exempt from either the natural light or natural ventilation requirement if all of the following requirements are met:

      (i)   when either natural ventilation or natural light is not provided, the room(s) are provided with mechanical ventilation in accordance with Table 18-28-403.3 of this Code and artificial light in accordance with Section 13-172-080; and

      (ii)   the area of such undesignated room or rooms does not exceed 15 percent of the total floor area of the dwelling unit; and

      (iii)   any dwelling unit with a floor area up to 1,300 square feet has at least 1 bedroom, as well as areas or rooms designated for living and dining, in addition to the multi-purpose room(s); and

      (iv)   any dwelling unit with a floor area over 1,300 square feet has at least 2 bedrooms as well as areas or rooms designated for living and dining, in addition to the multi-purpose room(s).

   Provided, however, that the exemption for multi-purpose rooms set forth in this subsection (c) shall not apply to any newly constructed building for which a permit was issued after April 1, 1998.

(Added Coun. J. 4-29-98, p. 66679, § 1; Amend Coun. J. 9-14-16, p. 31143, § 4; Amend Coun. J. 11-9-16, p. 36266, § 26*; Amend Coun. J. 9-6-17, p. 55278, Art. II, § 44)

* Editor's note – The amendment of Coun. J. 11-9-16, p. 36266, § 26 to this section did not take into account the amendment of Coun. J. 9-14-16, p. 31143, § 4, which renders the later amendment unnecessary.

13-172-070 Natural light.

   (a)   Lighting standards. In the application of the provisions of this chapter, the standard of natural light, unless otherwise specifically required by the building provisions of this Code for special occupancies and uses (described in Section 13-172-060), shall be based on 250 footcandles (2,691 lux) of illumination on the vertical plane adjacent to the exterior of the light- transmitting device in the enclosure wall and shall be adequate to provide an average illumination of at least 6 footcandles (64.58 lux) over the area of the room at a height of 30 inches (762 mm) above the floor level.

   (b)   Minimum glazing area. Every room or space intended for human occupancy shall have an exterior glazing area of not less than 8 percent of the floor area. Natural light shall be provided by glazing areas that open onto courts, yards or public ways which comply with the requirements of Section 13-172-130, or by other approved means.

   (c)   Borrowed light for remote rooms. Where natural light for rooms or spaces without exterior 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 25 square feet (2.33m2). The plane of the opening through which light is borrowed for a remote room without windows shall be parallel to the window wall. The exterior glazing area shall be based on the total floor area being served.

(Added Coun. J. 4-29-98, p. 66679, § 1)

13-172-080 Artificial light.

   (a)   General. Artificial light shall be provided that is adequate to provide an average illumination of 10 footcandles (107 lux) over the area of the room at a height of 30 inches above the floor.

   (b)   Stairway Illumination. (i) All stairways within dwelling units and exterior stairways serving a dwelling unit shall have an illumination level on tread runs of 1 footcandle (11 lux). (ii) The control for activation of the required stairway lighting within a dwelling unit shall be operable from the top and bottom of each stairway without traversing any step of the stair. The illumination of an exterior stairway serving a dwelling unit shall be controlled from inside the dwelling unit, unless continuously illuminated or automatically activated.

(Added Coun. J. 4-29-98, p. 66679, § 1; Amend Coun. J. 9-6-17, p. 55278, Art. II, § 45)

13-172-090 Natural ventilation.

   (a)   General. Natural ventilation of an occupied space shall be through windows, doors, louvers or other natural openings to the outdoor air.

   (b)   Ventilation area required. The minimum openable area to the outdoors shall be 4 percent of the floor area being ventilated.

   (c)   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.

   (d)   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.

   (e)   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)

13-172-100 Mechanical ventilation.

   Mechanical ventilation shall conform to the applicable requirements set forth in Chapter 18-13 and Chapter 18-28 of this Code.

(Added Coun. J. 4-29-98, p. 66679, § 1; Amend Coun. J. 9-14-16, p. 31143, § 5; Amend Coun. J. 11-9-16, p. 36266, § 26*)

* Editor's note – The amendment of Coun. J. 11-9-16, p. 36266, § 26 to this section did not take into account the amendment of Coun. J. 9-14-16, p. 31143, § 5, which renders the later amendment unnecessary.