2006 New York Code - Alcoves.

 
    §  27-747 Alcoves. An alcove or room opening off another room or space
  shall be considered as a separate room in determining  its  requirements
  for  ventilation.  However,  for dwellings classified in occupancy group
  J-3, where the opening between the alcove and the room or  space  is  at
  least  eighty  percent of the area of the common wall and the floor area
  of the alcove does not exceed twice the area of the opening, the  alcove
  and  the  room  opening  into  the  alcove may be considered as a single
  space.