§ 218. Alterations. 1. Any non-fireproof tenement erected after May
fifteenth, nineteen hundred two, having apartments extending from street
to yard and having one or more outer courts on a side lot line four feet
or more in width or inner courts which alone or together with adjoining
courts are eight feet or more in width and twelve feet six inches or
more in depth, may be altered into apartments opening either on the
street or the yard, provided all such altered apartments also have
windows opening on such a court. All such altered apartments shall be
provided with a second means of egress as required by section two
hundred thirty-one. The entrance and stair halls of such tenement shall
be fire-retarded.

2. No room in the cellar or basement of any tenement shall be
constructed or altered to be occupied for living purposes unless all of
the conditions of section thirty-four and of subdivision eight of
section twenty-six in regard to multiple dwellings erected after April
eighteenth, nineteen hundred twenty-nine, are complied with, except that
the minimum depths of yards and courts prescribed for tenements in
subdivision one of section two hundred twelve shall be substituted for
the minimum depths referred to in section thirty-four.

3. Any additional room or hall constructed or created in a tenement
shall comply in all respects with the provisions of this article
respecting rooms or halls in tenements erected after April eighteenth,
nineteen hundred twelve, except that in any tenement erected after April
fourteenth, nineteen hundred three, such rooms or halls may be of the
same height as the other rooms or halls on the same story.

4. The number of apartments or suites of rooms on any story in any
tenement erected after April twelfth, nineteen hundred one, may be
altered so as to increase or decrease the number of living rooms
provided such dwelling shall conform with the applicable provisions of
sections two hundred thirty-five and two hundred thirty-six.

5. If the number of apartments or suites of rooms in any old-law
tenement is increased, the entrance hall and both sides of the walls of
the stair halls adjoining the altered apartment shall be fire-retarded,
the stairs shall extend to the roof and there shall be no inside stairs
from the entrance story to a cellar, or to a basement or other story
below the entrance story. However, such inside stair may be permitted
provided such stair is constructed of incombustible material, has closed
risers, is enclosed between the entrance story and the next lowest story
with fireproof materials having a standard fire-resistive rating of at
least three hours, and has fireproof doors and door assemblies at the
top and bottom with the doors and door assemblies at the top and bottom
with the doors self-closing. The soffit of any stair immediately above
an inside cellar stair shall be fire-retarded and the jib partitions
enclosing such cellar stair at the first story shall be of incombustible
material or fire-retarded on both sides with materials having a standard
fire-resistive rating of at least one hour.

6. If any old-law tenement shall be so altered as to increase the
number of rooms therein by one-third or more, or if such tenement is
increased both in number of rooms and in height and after such
alteration is more than four stories or parts of stories above the curb
level, or if such tenement is over three stories in height and is
combined with another old-law tenement and the combined area on any
story exceeds three thousand square feet, the stair halls, entrance
halls and other public halls of the whole dwelling shall be made to
conform to the requirements of subdivision two of section two hundred
thirty-three and sections two hundred thirty-four to two hundred
thirty-eight inclusive, except that such combined tenements, if over
three stories in height, shall have in the roof a fireproof bulkhead
with a fireproof self-closing door.

7. In lieu of fire retarding required under subdivision five, there
may be installed in public halls an automatic dry pipe valve system or,
where halls are heated, an automatic wet pipe system. Where a sprinkler
system is installed it shall be equipped on each story with heads in
such number and spaced to protect the complete area of the public halls
and stairs and shall be constructed, located and arranged on every stair
and entrance hall and in every closet opening therefrom in such a manner
as the department may require. Such sprinkler system shall be maintained
continuously in good repair and serviceable condition.