Section 27-123.2. Provision of sprinklers in existing buildings

Notwithstanding any provision of law to the contrary, the provisions  of
  section  27-954  of  this  code  shall  apply  to  alterations  made  to
  buildings, as well as to changes in  occupancy  or  use,  as  set  forth
  below:
    (a)  The  provisions  of section 27-954 of this code shall apply to an
  entire existing building that is being altered, when  such  building  is
  classified  in  occupancy  group J-2 and will have four or more dwelling
  units upon the completion  of  the  alterations,  or  is  classified  in
  occupancy group J-1, and when the costs of making any alterations to any
  such  J-1  or  J-2 building within any twelve-month period exceeds fifty
  percent of the building value.
    (b) The provisions of section 27-954 of this code shall  apply  to  an
  entire  existing  building  when  the  occupancy  classification  of the
  building will  change  to  a  residential  occupancy  group  other  than
  occupancy group J-2 with not more than three dwelling units or occupancy
  group J-3.
    (c)  The  provisions of section 27-954 of this code shall apply to any
  space: (1) when alterations thereto involve a change in the occupancy or
  use thereof to a residential occupancy group other than occupancy  group
  J-2  with  not more than three dwelling units or occupancy group J-3, or
  (2) when the costs of making alterations thereto within any twelve-month
  period exceeds fifty percent of the value of the space.
    (d) For the purposes of this section, the cost of  making  alterations
  and  the  value of any such building or space shall be determined as set
  forth in section 27-119 of this chapter;  provided,  however,  that  for
  purposes  of  this  section:  (1)  the  cost  of making alterations to a
  residential building shall be determined based on the aggregate cost  of
  alterations  to the residential portions of such building, and the value
  of such a building shall be determined based on the aggregate  value  of
  the  residential portions of the building, exclusive of the value of any
  non-residential portions of the building; and (2)  the  cost  of  making
  alterations to residential spaces in a non-residential building shall be
  determined  based  on the collective cost of alterations to such spaces,
  and the value of such residential spaces shall be  determined  based  on
  the aggregate value of all such spaces in the building, exclusive of the
  value of any non-residential portions of the building.
    (e) When a system of automatic sprinklers is installed in any existing
  building  or  space  pursuant  to this section, such system shall comply
  with the requirements  of  this  code  and  any  other  laws  and  rules
  applicable  to  the  occupancy  group in which such building or space is
  classified or in which such building or space  would  be  classified  if
  such building or space were classified under this chapter.