NY Mult Dwell L § 52 (2021)
2021 New York Laws MDW - Multiple Dwelling Article 3 - Multiple Dwellings--General Provisions Title 2 - Fire Protection and Safety 52 - Stairs.

§  52.  Stairs.  1.  In  every  multiple  dwelling erected after April   eighteenth,  nineteen  hundred  twenty-nine,   every   interior   stair,   fire-stair  and  fire-tower  and every exterior stair in connection with   any dwelling altered or erected after January  first,  nineteen  hundred   fifty-one, shall be provided with proper balustrades or railings and all   such  interior and exterior stairs shall be kept in good repair and free   from any encumbrance. Every such stair, fire-stair and  fire-tower  more   than  three  feet eight inches wide shall be provided with a handrail on   each side.2. The upper surface of every balustrade  or  railing  placed  in  any   stair  after April eighteenth, nineteen hundred twenty-nine, shall be at   least two feet six inches and at most two feet eight  inches  above  the   front  edge  of  the  stair treads, and at any stair landing shall be at   least two feet eight inches and at most three feet above  the  level  of   such landing.3.  The  treads  and  risers of every stair, fire-stair and fire-tower   constructed after April eighteenth, nineteen hundred twenty-nine, in any   multiple dwelling shall be of  uniform  height  and  width  in  any  one   flight. Each tread, exclusive of nosing, shall be not less than nine and   one-half   inches   wide;   each   riser  shall  not  exceed  seven  and   three-quarters inches in height; and the product of the number of inches   in the width of the tread and the number of inches in the height of  the   riser shall be at least seventy and at most seventy-five.4. No winding stairs shall be constructed in any multiple dwelling.5. a. Except as otherwise provided in paragraph b of this subdivision,   every   stair  constructed  after  April  eighteenth,  nineteen  hundred   twenty-nine, leading to a cellar or basement from the first story  above   shall  be  entirely  enclosed  with fireproof walls and be provided with   fireproof doors and assemblies at both top and bottom,  with  the  doors   self-closing;  except that, in a non-fireproof multiple dwelling erected   before such date, where such a stair is permitted such  enclosing  walls   may be fire-retarded.b.  When  the  first  floor or a part thereof, in a fireproof multiple   dwelling, is used for business purposes, a stair leading to a cellar  or   basement  from  such business space shall be enclosed in fireproof walls   having a fire-resistive rating of at least three hours and  be  provided   with  a  fireproof  door  and  assembly  at  the  bottom,  with the door   self-closing. No opening shall be permitted between such business  space   and the remainder of the dwelling.6.   The  department  shall  have  the  power  to  make  supplementary   regulations relating to fire-towers.7. In every multiple dwelling  erected  under  plans  filed  with  the   department  after  January first, nineteen hundred sixty, on every story   above the entrance story every door opening into such stair shall be  so   hung  and  arranged that in opening and when opened it shall at no point   reduce the clear and unobstructed required width of the stair  or  stair   landing.8. The provisions of this section shall not apply to a stair within an   apartment  provided  that  each  level of the apartment is provided with   required means of egress complying with the provisions of this article.