§ 27-331 Exterior walls.
AC § 27-331
Exterior walls shall comply with the fire-resistance rating requirements of table 3-4. Where provisions of this code require a space or facility to be enclosed, the construction requirements for the enclosure shall not apply to any exterior wall that forms part of the enclosure.
(a)Openings in exterior walls. In addition to the requirements of table 3-4 and subchapters six and eight of this chapter, exterior openings above the third floor level of a building or above a height of forty feet, except buildings in occupancy group J-3, open parking structures, and buildings of construction classes II-D and II-E, shall have opening protectives when (1) any part of the opening is less than thirty feet distant in a direct unobstructed line not in the same plane, from an opening in another building or from a wood frame building or (2) any part of the opening is above and less than thirty feet in a direct unobstructed line from, any roof construction that has a fire-resistance rating of less than one hour or that has unprotected openings therein within this distance, whether the roof construction is on the same building or on an adjacent building.
(b)Opening protective required ratings. In a building or space classified in occupancy group A, all opening protectives shall be three-quarter hour (class E) opening protectives meeting the requirements of reference standard RS 5-8. Such protectives shall be fixed self-closing or automatic. Alternatively, these openings may be protected with three-quarter hour (class F) protectives together with outside sprinklers installed in accordance with construction requirements of subchapter seventeen of this chapter. In such cases, there shall be an automatic dry pipe sprinkler head centered over each opening with the orifice directed against the opening. All opening protectives required by table 3-4 or by subdivision (a) above in buildings classified in other than occupancy group A shall be three-quarter hour (class F) openings.
(c)First story openings. Opening protectives required by table 3-4 may be omitted in show windows or other openings on the lowest story of a building facing on a street or public space.
(d)Nonautomatic protectives. Required opening protectives in exterior openings, if not self-closing or automatic, shall be kept closed by the occupants at all times when not required for light or ventilation under the provisions of subchapter twelve of this chapter.
(e)Construction of unprotected openings. Exterior windows and doors, including their frames and glazing, that are not required by this code to have a fire-protection rating, may be of combustible materials. Below a height of seventy-five feet, slow-burning plastic glazing may be used in windows. Glazing in balcony doors shall comply with the requirements of paragraph four of subdivision (g) of section 27-369 of article five of subchapter six of this chapter.
(f)Vertical separation of openings. In buildings classified in occupancy groups A, B, C, D and E, exceeding three stories or forty feet in height, openings located vertically above one another in exterior walls except in stairway enclosures, shall be separated by a spandrel wall at least three feet high between the top of one opening and the bottom of the opening immediately above; or each such opening above the lower one shall be protected against fire by an opening protective; or a fire canopy of noncombustible materials, extending out at least two feet horizontally from the wall and at least as long as the width of the lower opening, shall be constructed between the two openings. Spandrels and fire canopies shall be constructed to provide at least the fire-resistance rating required for the exterior wall, but in no event less than one hour.
