Section 107. Public halls

1. Every public vestibule or other public hall
  shall  comply  either  with  the  provisions  of  section  one   hundred
  forty-nine  for  non-fireproof multiple dwellings, so far as applicable,
  or with the provisions of subdivision two of this section,  except  that
  the  provisions  as  to  ventilation  shall  not apply to any part of an
  entrance hall within sixty feet in a  straight  line  from  an  entrance
  door.
    2.  If  such a dwelling does not comply with the applicable provisions
  of section one hundred forty-nine, it  shall  comply  with  all  of  the
  following:
    a.  Every  public vestibule or hall shall be everywhere at least three
  feet eight inches in clear width.
    b. Every such public vestibule or hall shall  be  separated  from  all
  other parts of the dwelling by fireproof walls.
    c.  All  openings  from  such  a  public  vestibule or hall to stairs,
  fire-stairs, fire-tower balconies, shafts, apartments or suites of rooms
  shall be protected by fireproof doors and  assemblies,  with  the  doors
  self-closing,  except  that  such  doors  and  assemblies  shall  not be
  required in any fireproof class B multiple dwelling  for  any  apartment
  consisting  of  one  room opening directly upon a public hall or for any
  apartment of three rooms or less in a college or school dormitory.
    d. Such a public vestibule or hall shall not be  required  to  have  a
  window,  but  if  it  does not have a window opening to the outer air it
  shall be equipped for artificial lighting and be properly lighted at all
  times.
    e. Except for that part of an entrance hall within  sixty  feet  in  a
  straight  line  from  an  entrance  door such a public vestibule or hall
  without a window to the outer air shall be ventilated to the  outer  air
  by  means of gravity vent flues at least twelve inches in each dimension
  or by mechanical means approved by the department.  There  shall  be  at
  least  one vent flue opening of at least twelve inches in each dimension
  for each one thousand cubic feet of air content of such public vestibule
  or hall. Such vent flues shall be  continuous  for  the  height  of  the
  dwelling  and  the  openings  at  each story shall be equipped with fire
  dampers held open by a fusible link at each opening and properly  hooded
  or provided with louvres at the top above the roof.
    f.  If  a  window  to  the  outer  air  is provided in any such public
  vestibule  or  hall,  such  vestibule  or  hall  shall  nevertheless  be
  ventilated  as provided in paragraph e, except that if such a window has
  a glazed area of at least twelve square feet and at least one  tenth  of
  the  superficial floor area of the vestibule or hall, readily accessible
  to the outer air to the extent of at least five and one-half square feet
  of its area, no vent flues need be provided within a distance  of  forty
  feet from each side of such window.
    3.  The  requirements of this section as to ventilation shall apply to
  all parts of an entrance hall more than sixty feet distant in a straight
  line from an entrance door, to all returns  or  recesses  that  lead  to
  elevators  and  extend farther from the hall which they adjoin than four
  times their width, and to all other returns or  recesses  from  entrance
  halls that extend farther than their width.
    4.  Any  part of a public hall that is shut off from any other part of
  such hall by a door or doors shall be deemed a separate hall.