13-48-090 Exceptions to area limitations.

   (a)   Area Increase for Street Frontage and Separation. In buildings except institutional and assembly units, when more than 25 percent of the perimeter of a building faces a public street or other open area not less than 30 feet wide accessible to a public street, the allowable basic floor area may be increased as follows:

      (1)   When (I) equals the percentage by which areas established in Sections 13-48-070 and 13-48-080 may be increased, “P” equals the perimeter of the building and “F” equals the frontage, the following formula shall be used:

 

I	=	200F P	–	50

 

      Such increase shall not exceed 100 percent of the established basis floor area.

   (b)   Area Increase for Sprinklers. Floor areas may be increased 100 percent of the areas established in Sections 13-48-070, 13-48-080 and subsection (a) of this section when the building is equipped throughout with an approved automatic sprinkler system; provided that the provisions of this subsection shall not apply to a building in the Wrigley Field Adjacent Area in which a special club license is located.

   (c)   Area Increase for Two-Source Water Supply Sprinkler Systems. Floor areas of buildings, except Class A Residential and Class B Institutional, may be increased an additional 50 percent of the areas established in subsection (b) of this section when the automatic sprinkler system is supervised and provided with a two-source water supply, one of which shall be provided with an emergency power supply; provided that the provisions of this subsection shall not apply to a building in the Wrigley Field Adjacent Area in which a special club license is located.

   (d)   Areas of Basements. The area of a basement shall not exceed the maximum floor area permitted for the building; provided, however, that every basement exceeding 40,000 square feet in area shall be subdivided by fire walls complying with the requirements of Section 15-8-010 into areas not exceeding 40,000 square feet.

   (e)   Type III Schools. C-3 school area limitations are not applicable to Type III schools. 8,000 square feet or less in buildings of mixed occupancies of construction Types III or better.

   (f)   The areas of the individual buildings serviced by the covered mall, exit passages and/or the exterior shall each comply with the allowable areas established in Sections 13-48-070 and 13-48-080 with applicable increases as allowed in this Section 13-48-090.

      (1)   The entire building shall be 100 percent sprinklered. The sprinkler system shall be supervised and provided with a two-source water supply.

      (2)   The covered mall area is to be equipped with approved smoke activated smoke and heat venting devices in the roof. The venting area shall be sized to provide one square foot of vent area for each 100 square feet of the largest atrium floor opening, or mechanical exhaust of 2 cfm for each square foot of the largest atrium opening. Minimum size of vent opening shall be ten square feet or 2,000 cfm mechanical exhaust. Location and installation of vents to be approved by the fire commissioner.

      (3)   The area separations may be eliminated as presently required in Section 15-8-240(a)(2) of this Code.

(Prior code § 51-2.4; Amend Coun. J. 1-11-06, p. 68371, § 3; Amend Coun. J. 5-18-16, p. 24131, § 32)