Section 277. Occupancy permitted

Any building in any city of more than one
  million persons which at any  time  prior  to  January  first,  nineteen
  hundred  seventy-seven was occupied for loft, commercial, institutional,
  public,   community   facility   or   manufacturing    purposes,    may,
  notwithstanding  any  other article of this chapter, or any provision of
  law covering the same subject matter (except as  otherwise  required  by
  the local zoning law or resolution), be occupied in whole or in part for
  joint  living-work  quarters for artists or general residential purposes
  if such occupancy is in compliance with this article.    Such  occupancy
  shall be permitted only if the following conditions are met and complied
  with.
    1. (a) The exterior walls of the building shall be non-combustible and
  have a fire-resistive rating of at least three hours unless the exterior
  wall  or  walls,  measured  on  a horizontal plane perpendicular to said
  exterior wall or walls, is a minimum of thirty feet distant in a  direct
  unobstructed  line  from  another  structure,  except  that  a  wet pipe
  sprinkler system, with maximum sprinkler spacing of four feet,  must  be
  provided along such wall or walls to protect exposed, unrated columns or
  beams at the interior of the wall in non-fireproof buildings.
    (b)   Window  openings  in  exterior  walls  shall  conform  with  the
  limitations of table 3-4 chapter twenty-six of the  administrative  code
  of  the  city  of  New  York, unless such windows are fire protected and
  provided with either a minimum of  one  sprinkler  head  per  window  or
  window  automatic  closing  devices,  acceptable  to  the  department of
  buildings.
    2. The building (a) is  of  fireproof  construction,  as  provided  in
  section   one   hundred  one  of  this  chapter,  or  is  of  class  two
  construction, as provided by the requirements of the building  code  and
  regulations  of  the city of New York in effect prior to December sixth,
  nineteen hundred sixty-eight; or
    (b) if non-fireproof, does not exceed a height  of  six  stories,  and
  eighty-five feet measured to the ceiling of the highest floor in a depth
  of  one  hundred feet; or does not exceed a height of seven stories, and
  eighty-five feet and a depth of one hundred feet and is wet  sprinklered
  throughout;  and  has  a  maximum  floor area between the two hour rated
  partitions constructed in  accordance  with  section  C26-504.2  of  the
  administrative code of the city of New York of:
    (i) three thousand square feet; or
    (ii)  five thousand square feet if the building is six stories or less
  in height and is fully wet sprinklered; or
    (iii) five thousand square feet if the building is  seven  stories  in
  height and is fully wet sprinklered and has a stand pipe system; or
    (iv) ten thousand square feet if the building is fully wet sprinklered
  and has one hour rated ceilings.
    (c)  complies with the requirements of table 3-4 chapter twenty-six of
  the administrative code of the city of New York for J-2 occupancy.
    3. Any part of the building may  be  occupied  for  manufacturing  and
  commercial  purposes  (as  permitted by local zoning law or resolution),
  provided, however, that only the second story and below may be  occupied
  for uses listed as medium fire hazard in rules of the board of standards
  and appeals implementing the labor law unless the entire building is wet
  sprinklered;  in  addition,  high  fire  hazard occupancies shall not be
  permitted in any portion of the building.
    4. All areas occupied for manufacturing or commercial  purposes  shall
  be  protected  by  an approved wet-pipe automatic sprinkler system. Such
  wet-pipe automatic sprinkler system shall extend to and  include  public
  hallways and stairways coincidentally serving residential occupancies.

    5.  All occupancies or tenancies shall be separated by a vertical fire
  separation, extending to the underside of the floor above and  having  a
  minimum  fire-resistance  rating of at least one hour and conform in all
  respects with applicable zoning  regulations.  No  separation  shall  be
  required  between the working and living portions of a joint living-work
  quarters for artists.
    6. The building (a) complies with all requirements imposed on  old-law
  tenements by sections two hundred twelve and two hundred sixteen of this
  chapter  and on converted dwellings by sections one hundred eighty-five,
  one  hundred  eighty-six,  one   hundred   eighty-eight,   one   hundred
  eighty-nine,  one hundred ninety, one hundred ninety-one and one hundred
  ninety-four of this chapter, in addition to those  provided  in  section
  two  hundred  seventy-eight  of  this  article and (b) complies with the
  standards of lighting, ventilation, size of rooms, alcoves and balconies
  contained  in  section  C26-1205.0  through   and   including   sections
  C26-1205.5  and C26-1205.7 of the administrative code of the city of New
  York, except as otherwise provided in paragraph (d) of subdivision seven
  of this section.
    7. Minimum light and air standards for joint living-work quarters  for
  artists  or  general  residential portions of lofts or manufacturing and
  commercial buildings altered to residential use shall  comply  with  the
  following:
    (a) Portions of such buildings which are occupied exclusively as joint
  living-work  quarters for artists as permitted by local law shall comply
  with the following:
    (i) The minimum size of a joint living-work quarters for artists shall
  be twelve hundred square feet of interior  space,  except  as  otherwise
  authorized  by  the zoning resolution of the city of New York, for units
  occupied for residential purposes on or before January  first,  nineteen
  hundred eighty-five.
    (ii)  Joint  living-work  quarters  for  artists  shall conform to the
  standards for light and ventilation of sections C26-1205.0  through  and
  including  section  C26-1205.7 of the administrative code of the city of
  New York.
    (b) Portions of such  buildings  which  are  occupied  exclusively  as
  residential  units  as  permitted  by  local  law  shall comply with the
  following:
    (i) Every dwelling unit shall have one or more windows:
    A. which open onto a street, a court with a dimension of fifteen  feet
  perpendicular  to  the  windows and one hundred square feet minimum area
  above a setback or a thirty foot rear yard; or
    B. for corner lots or lots within one hundred feet of a corner,  where
  the minimum horizontal distance between such windows opening onto a rear
  yard and the rear lot line is at least twenty feet; or
    C.  for  interior  lots, where the minimum horizontal distance between
  such windows opening onto a rear yard and any wall opposite such windows
  on the same or another zoning lot is at least twenty feet and  not  less
  than  a  distance  equal  to  one-third of the total height of such wall
  above the sill height of such windows; but need not exceed  forty  feet;
  or
    D.  for  interior  lots  where the minimum horizontal distance between
  such windows opening onto a rear yard and any wall opposite such windows
  on the same or another zoning lot is  at  least  fifteen  feet  and  the
  minimum size of such dwelling unit is twelve hundred square feet; or
    E.  in  no  event shall the distance between such windows and the rear
  lot line be less than five feet; and
    F. yards and courts may be existing or may be new in  buildings  seven
  stories or less in height.

    (ii)  The minimum required ratio of window area opening onto a street,
  rear yard, or court to the floor area of every living room shall:
    A.  be  ten  percent  where the floor area of such living room is less
  than five hundred square feet; or
    B. decrease, by one percent for every one hundred square feet  greater
  than  five  hundred  square feet of floor area of such living room, to a
  minimum of five percent; and
    C. in no event shall the distance between such  window  area  and  the
  rear lot line be less than five feet; and
    D.  at  least  fifty  percent  of  the  required  window area shall be
  openable.
    (c) Ventilation of spaces other than living rooms, including  enclosed
  work  spaces  for joint living-work quarters for artists shall be either
  in accordance with this section or in accordance with the administrative
  code of the city of New York.
    (d) No building converted pursuant to this article shall be  enlarged,
  except  where  the  underlying  zoning district permits residential use.
  Such an enlargement shall be in conformance with  the  bulk  regulations
  for  conforming  residential  use  for  new construction and shall be in
  conformance with the provisions of section twenty-six of  this  chapter.
  No  interior  floor  area  enlargement  shall be permitted except that a
  mezzanine with a minimum headroom of seven feet shall be allowed  within
  individual  dwelling  units,  provided that the gross floor area of such
  mezzanine does not exceed one-third of the floor area  contained  within
  such dwelling unit. No mezzanine shall be included as floor area for the
  purpose  of  calculating the minimum required size of a living room or a
  dwelling unit or for calculating floor area devoted  to  dwellings.  For
  the  purpose  of  this  article a mezzanine may be constructed above the
  level of the roof of a building as long as the aggregate  area  of  roof
  structures does not exceed one-third of the total roof area and the roof
  structures conform with applicable building code requirements.
    (e)  The kitchen located within dwelling units and having a floor area
  of eighty  square  feet  or  more  shall  have  natural  ventilation  as
  prescribed  in sections 27-749 and 27-750 of chapter twenty-seven of the
  administrative code of the city of New  York.  Open  kitchens  shall  be
  considered as part of the adjacent space where forty percent of the area
  of  the  separation between the spaces is open and without doors. If the
  floor area of the combined space  exceeds  seven  hundred  fifty  square
  feet,  a  separate bedroom shall not be required. When the floor area is
  less than eighty square feet the  kitchenette  shall  be  ventilated  by
  either of the following:
    (i) Natural means complying with sections 27-749 and 27-750 of chapter
  twenty-seven  of  the  administrative  code  of the city of New York and
  further that the windows shall have a minimum width of twelve inches,  a
  minimum  area  of three square feet, or ten percent of the floor area of
  the space, whichever is greater and be  so  constructed  that  at  least
  one-half  of  their  required  area  may  be opened.   When the space is
  located at the top story, the window or windows may be replaced  with  a
  skylight  whose minimum width shall be twelve inches, whose minimum area
  shall be four square feet or one-eighth of the floor area of the  space,
  whichever  is  greater  and  which shall have ventilation openings of at
  least one-half of the required area of the skylight.
    (ii) Mechanical means exhausting at least two cubic feet per minute of
  air per square foot of floor  area.  Where  doors  are  to  be  used  to
  separate  the  space,  the lower portion of each door shall have a metal
  grill containing at least forty-eight square inches of clean openings or
  in lieu of such grill, two clear opening spaces may be provided, each of
  at least twenty-four square inches, one between the bottom of each  door

  and  the  floor  and the other between the top of each door and the head
  jamb.
    (f)  When  bathrooms and toilet rooms are ventilated by natural means,
  the natural ventilation sources shall comply with sub-article 1205.0  of
  chapter  twenty-six  of  the administrative code of the city of New York
  and shall have an unobstructed free area of at least five percent of the
  floor area. In no case shall  the  net  free  area  of  the  ventilation
  sources  be  less  than one and one-half square feet. When bathrooms and
  toilet rooms are vented by mechanical means, individual vent  shafts  or
  ducts  constructed  of  non-combustible  materials  with a minimum cross
  section area of one square foot shall be utilized,  the  exhaust  system
  shall  be  capable of exhausting at least fifty cubic feet per minute of
  air. Means shall be provided for egress of air by louvers in  doors,  by
  undercutting  the  door, or by transfer ducts, grills or other openings.
  Toilet exhaust systems shall be arranged to expel air  directly  to  the
  outdoors.
    (g)  A  single  station  smoke detector shall be installed immediately
  outside each sleeping or bedroom area of each dwelling unit. Such device
  shall be designed and installed so as to detect smoke  and  activate  an
  alarm,  be  reasonably  free  from  false  alarms  and  provide  visible
  indication that the alarm is energized. Such device  shall  be  directly
  connected  to  the lighting circuit of the dwelling or rooming unit with
  no intervening wall switch and shall provide a  warning  signal  clearly
  audible  in  all  sleeping  quarters with intervening doors closed. Cord
  connected installations or smoke detectors  which  rely  exclusively  on
  batteries are not permissible.  Such devices shall either be approved or
  listed by an acceptable testing service or laboratory.
    8. All openings from apartments leading into a public hall or corridor
  shall  be  provided  with  fireproof doors and assemblies with the doors
  self-closing. Partitions between apartments on each floor shall  be  one
  hour fire rated partitions. All windows opening on fire escapes shall be
  provided  with  wire  glass,  unless such windows are protected by a wet
  pipe sprinkler head with a minimum of one head per window.
    9. Such  buildings,  in  regard  to  egress,  shall  comply  with  the
  following:
    (a) In a non-fireproof building there shall be:
    (i)  one  independently  enclosed stairway and a fire escape from each
  dwelling unit; or
    (ii) where the building is fully wet sprinklered and not in excess  of
  seventy-five  feet in height and not exceeding five thousand square feet
  in building area one independently enclosed stairway from each dwelling,
  and an independently enclosed hallway, of one  hour  fire  rating  where
  there are two or more tenants on a floor; or
    (iii)  a sprinklered enclosed hallway with access to two independently
  enclosed stairs.
    (b) In a fireproof building, there shall be:
    (i) an enclosed hallway and two independently enclosed stairs; or
    (ii) an enclosed hallway and one independently enclosed  stair  and  a
  screened   exterior  stair  in  conformance  with  section  two  hundred
  sixty-eight of the labor law with all glazed openings  thereon  equipped
  with wire glass; or
    (iii)  for  buildings not exceeding seven stories or seventy-five feet
  in height, egress conforming with the provisions  of  paragraph  (a)  of
  this subdivision; or
    (iv)  egress conforming with the provisions of section one hundred two
  of this chapter.
    (c) No more than two dwelling units shall open  directly  to  a  stair
  without an intervening enclosed hallway.

    (d) Enclosed hallways shall have a one hour fire rating.
    (e) Enclosed stairways shall be:
    (i)  one  hour  fire  rated in non-fireproof buildings four stories or
  less in height; or
    (ii) one hour fire rated and sprinklered  in  non-fireproof  buildings
  six stories or less in height; or
    (iii)   one  hour  fire  rated  in  non-fireproof,  fully  sprinklered
  buildings seven stories in height; or
    (iv) two hour fire rated in all other cases.
    (f) The travel distance to the means of egress shall comply with
    the administrative code of the city of New York.
    (g) Wooden stairs permitted by section one hundred eighty-nine of this
  chapter may be retained only if, in  addition  to  meeting  all  of  the
  requirements  set forth therein, they are within a fully wet-sprinklered
  enclosure,  and  the  stair  and  landing  soffit  are  fire   retarded,
  notwithstanding any other provisions.
    (h)  Every required stair shall extend through the roof by a bulkhead,
  except that a scuttle may be used if the dwelling does not  exceed  four
  stories  and  except  that  no bulkhead or scuttle is required where the
  roof is a peak roof with a pitch of more than fifteen degrees.
    (i) Mezzanines shall be provided with a stair at least  two  feet  six
  inches  wide  terminating not more than twenty feet from an exit door or
  fire escape, and all portions of such mezzanines shall be not more  than
  fifty feet from such exit door or fire escape.
    10.  In  buildings in excess of two stories in height, stairways shall
  be provided with skylights at least twenty square feet in  area,  glazed
  with  plain  glass  with  a wire screen over and under and provided with
  fixed or movable ventilators having a minimum open area of  one  hundred
  forty-four  square  inches.   In lieu of the skylight and ventilators, a
  window of equal area may be provided with fixed louvers having a minimum
  open area of one  hundred  forty-four  square  inches  installed  in  or
  immediately adjacent to the window.
    11.  Except as otherwise provided in this article, all shafts shall be
  enclosed with incombustible material of two hour fire rating and  comply
  with the administrative code of the city of New York, provided, however,
  existing  shaft  enclosures  constructed in part of combustible material
  may be retained if upgraded to obtain a two hour fire rating.
    12. Every kitchen or kitchenette or cooking  space  in  such  building
  shall comply with the requirements imposed on multiple dwellings erected
  after   April   eighteenth,  nineteen  hundred  twenty-nine  by  section
  thirty-three of this chapter.
    13. Such building  shall  comply  with  all  requirements  imposed  on
  multiple  dwellings  erected  after  April  eighteenth, nineteen hundred
  twenty-nine by title three of article three of this chapter.
    14. All interior iron columns  in  unsprinklered  buildings  shall  be
  protected  by  materials or assemblies having a fire-resistive rating of
  at least three hours. Where sprinklers are provided for an exterior wall
  as provided in subdivision one  of  this  section  or  in  a  fully  wet
  sprinklered  building  such  columns shall be protected by two sprinkler
  heads located eighteen inches or more away and each on opposite sides of
  such column but no further than four feet.   Such  sprinklers  shall  be
  provided  at  any  interior  column  where fire protection is omitted in
  non-fireproof buildings.
    15. The elevator shafts in  such  buildings  shall  be  enclosed  with
  incombustible  material  of  two  hour fire rating, except that existing
  elevator shaft enclosures constructed in part  of  combustible  material
  may  be  retained if upgraded to obtain a two hour fire rating; and have
  fireproof doors and assemblies with (a) the doors self-closing; or (b) a

  vestibule the walls of which shall be of  non-combustible  material  and
  have  a  minimum  two  hour  fire  resistive  rating,  with self-closing
  fireproof doors and be  fire-stopped;  or  (c)  where  the  elevator  is
  manually  operated  in fully sprinklered buildings have fireproof doors,
  with approved interlock devices.
    16. The requirements and standards prescribed in this section shall be
  subject to variation in specific cases by the commissioner of buildings,
  or the board of standards and appeals, of such city under  and  pursuant
  to  the  provisions  of  paragraph  two  of subdivision b of section six
  hundred forty-five and section six hundred sixty-six  of  the  New  York
  city charter.