Section 27-381. Requirements

Corridors  and  exits shall be provided with
  artificial lighting facilities, except as  otherwise  permitted  by  the
  provisions  of subchapter twelve of this chapter, in accordance with the
  following:
    (a) Illumination of at least two foot candles measured  at  the  floor
  level  shall  be maintained continuously, during occupancy, in exits and
  their access facilities for their full length, at changes  in  direction
  in  and intersections of corridors, balconies, exit passageways, stairs,
  ramps, escalators, bridges, tunnels, landings,  and  platforms,  and  as
  provided  in  subchapter  eight  of this chapter for places of assembly,
  except that this requirement shall not apply to dwelling units.
    (b) In buildings classified in occupancy  groups  B-1  and  B-2,  exit
  lighting need only be maintained when a section of floor is occupied.
    (c)  Illumination  shall  be  so  arranged that the failure of any one
  light shall not leave any area in darkness.
    (d) Phosphorescent  materials  shall  not  be  used  as  a  method  of
  providing  illumination,  nor  shall battery operated electric lights or
  portable lamps or lanterns be used as primary sources of lighting.
    (e) (1) Buildings and existing buildings containing an  F-4  place  of
  assembly  with  an  occupant load of three hundred or more persons shall
  install emergency lighting in each vertical exit serving  the  floor  on
  which  the  place of assembly is located so as to provide a continuously
  lighted passage to the exterior of the building. Such lighting shall  be
  connected  to  an emergency power source or to storage battery equipment
  meeting the requirements of the commissioner.
    (2) Existing buildings required to comply with this subdivision  shall
  install  the  emergency  lighting  on  or  before  April first, nineteen
  hundred eighty-seven.