Section 27-335. Exterior trim

For the purposes of this section, exterior
  trim shall be defined as any material, other than door and window frames
  and sash, that is applied to exterior walls and  which,  if  removed  or
  destroyed,  will  not  reduce  the  structural stability of the building
  enclosure, and which is installed so  as  not  to  reduce  the  required
  fire-resistance  rating  of  the  enclosure. Exterior trim shall include
  cornices,  overhanging  eaves,   fascias,   belt   courses,   pilasters,
  surrounds, gutters, leaders, half-timber work, shutters, trellises, etc.
    (a) Combustible exterior trim:
    (1)  May not be used on buildings required to be of construction group
  I except that slow-burning plastics or approved equivalent materials may
  be used up to a height of twenty-five  feet,  provided  that  such  trim
  covers  not  more  than five percent of the surface area of the building
  enclosure (openings not included), or not more than one thousand  square
  feet.
    (2) May be used to a height of forty feet on buildings of construction
  classes  II-A,  II-B,  and  II-C provided that such trim covers not more
  than ten percent of the surface area of the building enclosure (openings
  not included), projects not more than eight inches  beyond  the  outside
  face  of  the  building  enclosure, and has an exterior separation of at
  least fifteen feet measured from the outermost surface of the trim.
    EXCEPTION. Cornices, gutters, or overhanging  roofs,  when  permitted,
  may  project  up  to  three feet beyond the outside face of the building
  enclosure if they are at least eight inches above the  topmost  opening,
  are  firestopped  as  required by section 27-345 of article five of this
  suchapter and either:
    a. have their combustible structural members protected by soffits  and
  fascias   of  a  material  or  assembly  having  at  least  a  one  hour
  fire-resistance rating, or
    b. have all their combustible members  separated  from  the  roof  and
  ceiling  construction  by construction having the fire-resistance rating
  required for the exterior wall, with  at  least  four  inches  of  solid
  noncombustible  material  below,  at  the sides, and at the ends of such
  members;
    (3) May be used to an unlimited extent in  buildings  of  construction
  classes  II-D and II-E on exterior walls that are not required to have a
  fire-resistance rating.