Section 27-331. Exterior walls  


Latest version.
  • 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.