Article 1 Lighting and Ventilation

   a.   No multiple dwelling shall be so altered as to diminish the light and ventilation of any room in any way not approved by the department.

   b.   Every required window shall be so located as to light properly all portions of the room.

   c.   Any obstruction of required light and ventilation shall be unlawful.

   a.   Required windows. Every living room in a multiple dwelling erected after April eighteenth, nineteen hundred twenty-nine, shall have at least one window opening on:

      (1)   a street;

      (2)   a lawful yard or court on the same lot;

      (3)   a partially enclosed balcony or space above a setback which opens directly to a street, yard or court if the area of the front of such balcony or space open to the outer air is at least equal to seventy-five percent of the floor area of such balcony or space; or

      (4)   A completely enclosed balcony or space above a setback in a fireproof multiple dwelling if: the enclosure is not more than one story in height; the outer enclosing walls and roof are of incombustible materials; an area, glazed with clear plate glass or plastic equivalent, on the outer enclosing walls if at least fifty percent of the area of the interior enclosing walls; and at least fifty percent of such glazed area opens on a street, legal yard or court. One-half of such glazed area shall be openable. A living room does not include a kitchen under this paragraph.

   b.   No required window of a living room shall open on an offset or a recess of less than six feet in width.

   c.   Size of windows.

      (1)   The total area of all windows in the room shall be at least one-tenth the floor area of such room, except that when a room opens solely on a balcony or space above a setback the total area of such opening shall be one-tenth the combined floor area of the room and that portion of the balcony or space directly in front of such room. In determining the ratio of windows to floor area, the combined glazed area of windows and doors opening on a balcony or a space above a setback may be used.

      (2)   Every required window shall be at least twelve square feet.

      (3)   At least one-half of every required window shall open, except that for a mullioned casement window a minimum of five and one-half square feet is sufficient. In a room where a centralized mechanical ventilating system provides forty cubic feet of air per minute, twenty-five percent of the window area or five and one-half square feet of such area, whichever is greater, shall be openable.

      (4)   The top of one required window in every room shall be at least seven feet above the floor, except that in dwellings erected pursuant to plans filed after April twenty-third, nineteen hundred fifty-nine, and prior to June fourteenth, nineteen hundred sixty-seven, this requirement shall not apply.

   d.   Through ventilation.

      (1)   No part of any living room with windows, or doors in lieu thereof, opening on a balcony or space above a setback shall be more than thirty feet from the exterior face of the outer enclosing wall.

      (2)   In any dwelling unit in a non-fireproof multiple dwelling or in a dwelling unit of three rooms or less in a fireproof multiple dwelling, no part of any room shall be more than thirty feet from a window opening on a street or yard unless such room also opens on a legal court.

   e.   Openings on lot line. Every window and its assembly in a wall situated on a lot line, except a street line, shall be fireproof; the assembly shall have a fire resistive rating of at least three-quarters of an hour; and the window shall be glazed with wire glass at least onequarter of an inch thick. Every such window shall be of automatic selfclosing construction whenever it is less than fifty feet above the non-fireproof roof of another structure located thirty feet or less from the lot line.

   f.   Dining space. A dining space shall have a window which:

      (1)   Complies with the provisions of subdivision a of this section, and

      (2)   Has an area at least one-eighth the floor area of such dining space.

   a.   Required windows. Except as provided in subdivision c, every living room in a converted dwelling shall have at least one window opening on:

      (1)   A street,

      (2)   A yard or outer court which complies with the provisions of section one hundred seventy-two of the multiple dwelling law, or

      (3)   An inner court or shaft with minimum dimensions of three feet, nine inches in width and eight feet in length.  For a room located on the top story, a skylight of the dimensions required in subdivision b may be substituted for a window.

   b.   Size of windows.

      (1)   The total area of all windows in the room shall be at least one-tenth the floor area of such room.

      (2)   Every required window or skylight shall be at least twelve square feet, except that if the total area of windows in the room is one-eighth of the floor area this requirement shall not apply.

      (3)   At least one-half of every required window shall open. One-half of the skylight shall have ventilating openings, unless (a) the skylight is equipped with a minimum of one hundred and forty-four square inches of ventilation, and (b) there is at least one window in the room, and (c) the combined glazed area of the skylight and window is at least one-eighth of the floor area.

      (4)   The top of every required window shall be at least seven feet above the floor, except that on the top story it shall be a minimum of six feet above the floor.

   c.   Noncomplying rooms.

      (1)   A room which is noncomplying with the minimum room size requirements of subdivision b of section 27-2074 of article four of this subchapter or with the requirements of subdivisions a and b of this section may not be occupied unless it has a single or unbroken opening of not less than thirty-two and one-half square feet into an immediately adjoining room. Such adjoining room shall have a window on a street or a yard which complies with the provisions of section one hundred seventy-two of the multiple dwelling law, except that if the dwelling is two stories or less in height, the window of such adjoining room may open on an outer court or a court not less than four feet in width extending from street to yard.

      (2)   No room may be subdivided in any manner unless each subdivided portion meets the requirements of paragraph one of this subdivision, or of subdivision a of this section.

   a.   Required windows. Every living room in a new law tenement shall have a window opening on:

      (1)   A street, or

      (2)   A lawful yard or court.

   b.   Size of windows.

      (1)   The total area of all windows in the room shall be at least one-tenth the floor area of such room.

      (2)   Every required window shall be at least twelve square feet.

      (3)   At least one-half of every required window shall open.

      (4)   The top of one required window in a room shall be at least seven feet six inches above the floor.

   c.   Through ventilation.

      (1)   Every part of a dwelling unit of three rooms or less shall be either within eighteen feet of a street or yard or have a window opening upon a lawful court.

      (2)   If the window of any room opens on an inner court with a width of less than ten feet between the exterior wall of the dwelling and the lot line, there shall be a sash window connecting such room to an adjoining room within the dwelling unit. The sash window shall have at least ten square feet of glazed area, one-half of which shall open.

   d.   Dining space. A dining space shall have at least one window:

      (1)   That complies with the provisions of subdivision a; and

      (2)   That has an area not less than one-eighth the floor area of such dining space.

   a.   Required windows. Every living room in an old law tenement shall either have a window opening:

      (1)   On a street; or

      (2)   On a yard at least four feet in depth; or

      (3)   On a court or shaft at least twenty square feet in area open to the sky without a roof or skylight; or

      (4)   Above the roof of an adjoining building; or it shall meet the requirements of the multiple dwelling law. In the event that a window opens above the roof of an adjoining building and the light and air from the adjoining lot is thereafter diminished in any way, the department may determine that such a room is a noncomplying room and require compliance with the requirements of the multiple dwelling law. For a room located on the top story, a ventilating skylight opening to the outer air may be substituted for a window. At least one-half of every required window shall open.

   b.   Dining space. A dining space shall have at least one window which:

      (1)   Opens on a street, yard or legal court, and

      (2)   Has an area not less than one-eighth the floor area of such dining space.

   a.   Required windows. Every living room shall have at least one window open to a street, public place or an open and unobstructed yard, court or other required open space on the same lot as the dwelling.

   b.   Size of windows; substitutes for windows.

      (1)   The total area of all windows in the room shall be at least one-tenth the floor area of such room, or twelve square feet, whichever is greater.

      (2)   Skylights, opening directly to the outer air, transparent or translucent panels or doors, or other natural light transmitting media may be substituted for window openings, subject to the approval of the department, if they provide an equivalent amount of light to that transmitted through the window area required in paragraph one of this subdivision.

      (3)   At least forty-five percent of the required window area, skylight or other openings shall be openable to provide natural ventilation. If a mechanical ventilation system provides forty cubic feet of air per minute, the openable area may be reduced to twenty-five percent.

   c.   Noncomplying rooms.

      (1)   A living room in a oneor two-family dwelling constructed after January first, nineteen hundred thirty-eight which meets the minimum room size requirements of article four of this subchapter but does not comply with subdivision a of this section may not be occupied unless it has a single unbroken opening of not less than sixty square feet into an immediately adjoining room. The adjoining room shall have at least one window opening to the outer air and such window shall be not less than one-tenth of the combined floor area of the room.

      (2)   In a one- or two-family dwelling constructed prior to January first, nineteen hundred thirty-eight, an opening shall be required between a room without a window and an immediately adjoining living room with at least one window. Such opening shall have a minimum size of thirty-two and one-half square feet.