Section 504 Building Height Modifications

The heights permitted by Table 503 shall only be increased in accordance with this section.

Exception: The building height of one-story aircraft hangars, aircraft paint hangars and buildings used for the manufacturing of aircraft shall not be limited if the building is provided with an automatic fire-extinguishing system in accordance with Chapter 9 and is entirely surrounded by public ways or yards not less in width than one and one-half times the building height.

Where a building is equipped throughout with an approved automatic sprinkler system in accordance with Section 903.3.1.1, the value specified in Table 503 for maximum building height is increased by 20 feet (6096 mm) and the maximum number of stories is increased by one story. These increases are permitted in addition to the building area increase in accordance with Sections 506.2 and 506.3. For Group R buildings equipped throughout with an approved automatic sprinkler system in accordance with Section 903.3.1.2, the value specified in Table 503 for maximum building height is increased by 20 feet (6096 mm) and the maximum number of stories is increased by one story, but shall not exceed 60 feet (18 288 mm) or six stories, respectively.

Exceptions:

1. Buildings, or portions of buildings, classified as a Group I-2 occupancy of Type IIB, III, IV or V construction.
2. Buildings, or portions of buildings, classified as a Group H-1, H-2, H-3 or H-5 occupancy.
3. Fire-resistance rating substitution in accordance with Table 601, Note d.

Rooftop structures including but not limited to roof tanks and their supports, ventilating, air conditioning, combined heat and power systems and similar building service equipment, bulkheads, penthouses, greenhouses, chimneys, and parapet walls 4 feet (1219 mm) or less in height shall not be included in the building height of the building or considered an additional story unless the aggregate area of all such structures, exclusive of any solar thermal and solar (photovoltaic) collectors and/or panels and their supporting equipment, exceeds 33¹/₃ percent of the area of the roof of the building upon which they are erected. Rooftop structures shall be constructed in accordance with Section 1509.

Exception: Solar thermal and solar electric (photovoltaic) collectors and/or panels and their supporting equipment that exceed 33¹/₃ percent of the area of the roof of the building upon which they are erected shall not be included in the height of a building or considered an additional story.