Section 1510 Unoccupied Rooftop Structures
14B-15-1510 The provisions of Section 1510 of IBC are adopted by reference with the following modifications:
Added Coun. J. 4-10-19, p. 100029.
Amended Coun. J. 2-19-20, p. 14474.
The combined area of parapet walls, unoccupied rooftop structures, rooftop access penthouses in accordance with Section 1510.2 and structures accessory to an occupiable rooftop in accordance with Section 1513.1.1 shall not exceed one-third the area of the supporting roof deck. Such rooftop structures shall not be required to be included in determining building height, number of stories above grade plane or building area in accordance with Chapter 2, nor shall the area of such rooftop structures be included in determining the fire areas specified in Section 901.7.
Exception: If the combined area of rooftop structures exceeds one-third the horizontal area of the supporting roof deck, the height and area of the rooftop structures shall be considered in determining building height, number of stories above grade plane, building area and fire area.
Cooling towers located on the roof deck of a building and greater than 250 square feet (23.2 m2) in base area or greater than 15 feet (4572 mm) in height above the roof deck, as measured to the highest point on the cooling tower, where the roof is greater than 50 feet (15 240 mm) in height above grade plane shall be constructed of noncombustible materials. The base area of cooling towers shall not exceed one-third the area of the supporting roof deck.
Exception: Drip boards and the enclosing construction shall be permitted to be of wood not less than 1 inch (25 mm) nominal thickness, provided that the wood is covered on the exterior of the tower with noncombustible material.
Aerial supports shall be constructed of noncombustible materials.
Exception: Aerial supports not greater than 12 feet (3658 mm) in height as measured from the roof deck to the highest point on the aerial supports shall be permitted to be constructed of combustible materials.