Section
27-2057 Lighting and Ventilation in Multiple Dwellings; General Requirements
27-2058 Lighting and Ventilation of Living Rooms in Multiple Dwellings Erected after 1929
27-2059 Lighting and Ventilation of Living Rooms in Converted Dwellings
27-2060 Lighting and Ventilation of Living Rooms in New Law Tenements
27-2061 Lighting and Ventilation of Living Rooms in Old Law Tenements
27-2062 Lighting and Ventilation in One- and Two-Family Dwellings

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Sec. 27-2057 Lighting and Ventilation in Multiple Dwellings; General Requirements

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.

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Sec. 27-2058 Lighting and ventilation of living rooms in multiple dwellings erected after 1929

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;
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 windows 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 one-quarter of an inch thick. Every such window shall be of automatic self-closing 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.

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Sec. 27-2059 Lighting and ventilation of living rooms in converted dwellings

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 storey 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 storey it shall be a minimum of six feet above the floor.

c. Non-complying rooms

1. A room, which is non-complying 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 storeys 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.

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Sec. 27-2060 Lighting and ventilation of living rooms in new law tenements

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.

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Sec. 27-2061 Lighting and ventilation of living rooms in old law tenements

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 on 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 non-complying room and require compliance with the requirements of the Multiple Dwelling Law. For a room located on the top storey 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-eight the floor area of such dining space.

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Sec. 27-2062 Lighting and ventilation in one- and two-family dwellings

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. Non-complying rooms

1. >A living room in a one- or 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.

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