Section 27-962. Sources of water supply for sprinkler systems

Sprinkler
  systems shall be provided with water from the following sources.
    (a) Two automatic sources  of  water  supply  shall  be  provided  for
  sprinklers in:
    (1) Buildings classified in occupancy group A.
    (2)  Buildings  classified  in  occupancy group C when the area on one
  floor exceeds twenty thousand square feet.
    (3) Buildings classified in occupancy group F-1a when open  heads  are
  required for stages of unlimited size.
    (b)  At  least  one automatic source of water supply shall be provided
  for sprinklers installed in all occupancy groups, except those listed in
  subdivision (a) and except  as  provided  in  subdivision  (c)  of  this
  section.
    (c)  The  domestic  water  supply may be used to supply any sprinklers
  required  under  section  27-954  of  this  article  when  installed  in
  buildings classified in occupancy groups E, G, H and J, or to supply any
  sprinklers  required  under subdivision (aa) of said section, regardless
  of occupancy group classification, provided that  all  the  requirements
  stated in subdivision e of section 27-962 of this article are met.
    (d)  The  domestic  water  supply  may  be  used  to  supply  water to
  sprinklers in cooling towers if provision is made to automatically  stop
  the use of water through the domestic supply lines and provided that all
  of the requirements stated in subdivision (e) of this section are met.
    (e)  When the domestic water is used to supply sprinklers as permitted
  in subdivisions (c) and (d)  of  this  section,  all  of  the  following
  conditions shall be met:
    (1)  The  domestic water supply line from the tank or street supply is
  at least the size of the sprinkler line and that the capacity  available
  is at least equal to the capacity required for the sprinklers.
    (2)  The  domestic  water  supply line from the tank or street has the
  required pressure as provided in section 27-963 of this article.
    (3) The domestic water supply line is of  nonferrous  material  except
  when the domestic water supply is four inches or over.
    (4)  An  o.s.  and  y.  valve  or  an  approved  valve  having  visual
  indication, sealed open, is installed in the sprinkler supply branch, or
  such other valve  arrangement  as  may  be  provided  for  in  reference
  standard RS 17-2A or RS 17-2B, as applicable.
    (5)  The  pipe  connecting the domestic water supply and the sprinkler
  control valve is of nonferrous material and not less than twelve  inches
  long.
    (6)  The  number of heads in each fire section does not exceed twenty,
  except that the number of heads in each fire section may  exceed  twenty
  in  buildings classified in occupancy group J-2 or J-3 not exceeding six
  stories or seventy-five feet in  height  and  in  spaces  classified  in
  occupancy  group  J-2  or  J-3 in buildings not exceeding six stories or
  seventy-five feet in height, and no more than  ten  heads  are  supplied
  from any one domestic water riser.
    (7) The connection is made at the supply or riser side of any domestic
  branch control valves.
    (8)  In  connection  with  the  above  conditions,  the number of fire
  sections  having  twenty  or  less  heads  may  be  unlimited;  and  the
  installation  of  alarms in branches supplying fire sections shall be at
  the option of the owner, except that such alarms shall be provided where
  required by reference standard RS 17-2A or RS 17-2B.
    (9) A check valve is installed on the sprinkler supply branch.
    (f) Nonautomatic sprinkler systems shall be provided with:
    (1) Siamese connections in accordance with section 27-940  of  article
  three of this subchapter.

    (2) Malleable iron fittings approved for sprinkler installations.
    (3)  An  approved  automatic  fire  alarm  with direct connection to a
  central station of an approved operating fire  alarm  company  shall  be
  installed in the area protected by the sprinkler system.
    (g)  There  shall  be  no more than ten sprinkler heads connected to a
  plumbing riser supplying anything other than  sprinkler  heads,  and  no
  more  than  twenty  sprinkler  heads connected to a riser supplying only
  sprinkler heads in any fire section separated  by  two  hour  enclosures
  from adjoining fire sections. The number of sprinkler heads connected to
  a  riser  supplying  only sprinkler heads may exceed twenty in buildings
  classified in occupancy group J-2 or J-3 that do not exceed six  stories
  or  seventy-five  feet in height and in residential spaces classified in
  occupancy group J-2 or J-3 in buildings not  exceeding  six  stories  or
  seventy-five feet in height.
    (h) Standpipe risers may be used to supply water to sprinklers in high
  rise  buildings  classified  in  occupancy  groups  E, G, H and J and in
  existing office buildings, one  hundred  feet  or  more  in  height,  in
  accordance  with  applicable provisions of this subchapter and reference
  standards RS 17-1 and RS 17-2.
    (i) The domestic water supply in  buildings  classified  in  occupancy
  group  J-1  or  J-2  may  be used for sprinklers in corridors, in refuse
  chutes and in other similar areas, as approved by the commissioner.  The
  domestic  water  may  be  supplied  by direct public water connection or
  equipment and  pumps  approved  for  water  supply  in  accordance  with
  reference standard RS-16.