(a)        The minimum size, yard and density requirements of Sections 15-111, 15-22, 43-17 and 111-40 (REQUIREMENTS FOR LOFT DWELLINGS CONSTRUCTED PRIOR TO OCTOBER 13, 2010), may be replaced by the requirements of this Section for dwelling units, joint living-work quarters for artists or loft dwellings:

(1)        existing on September 1, 1980, for which a determination of residential or joint living-work quarters for artists occupancy has been made pursuant to paragraph (b) of Section 15-021, paragraph (a) of Section, 15-215, paragraph (b) of Section 42-324, paragraph (c)(2) of Section 42-325, or Section 74-782; or

(2)        that are registered Interim Multiple Dwellings or are found covered by the New York City Loft Board pursuant to Article 7C of the New York State Multiple Dwelling Law; or

(3)        that the Loft Board determines were occupied for residential use or as joint living-work quarters for artists on September 1, 1980.

(b)        Unless required by the Loft Board for the legalization of Interim Multiple Dwelling Units in the implementation of Article 7C of the New York State Multiple Dwelling Law, dwelling units or joint living-work quarters for artists described in paragraph (a) and existing on such dates may not be divided subsequently into units or quarters of less than 1,200 square feet, and loft dwellings may not be divided subsequently into dwellings that do not meet the requirements of Section 111-40.

No building that meets the density requirements of Section 15-111 or paragraph (c) of Section 111-40, may subsequently add additional units or quarters except in accordance thereof. No building to which the regulations of this Section have been applied may subsequently add additional units or quarters except in accordance with the requirements of Sections 15-111.

(c)        In lieu of the stated minimum size, yard, and density requirements of Sections 15-111, 15-22, 43-17 and 111-40, the following regulations shall apply:

(1)        The minimum size of a dwelling unit, joint living-work quarters for artists, or loft dwelling may be no less than 415 square feet of floor area, provided that all of the following requirements are met:

(i)        the unit or quarters shall contain one or more windows that open onto a street or 30 foot yard;

(ii)        the area of such required window shall be not less than eight percent of the floor area of the unit or quarters and 50 percent of the area of such required window shall be openable; and

(iii)        the interior dimension of the wall in which such required window is located shall be no less than 12 feet in width; or

(2)        The minimum size of a dwelling unit, joint living-work quarters for artists, or loft dwelling may be no less than 600 square feet of floor area, provided that all of the following requirements are met:

(i)        the unit or quarters shall contain one or more windows that open onto either:

(a)        a 10 foot yard, where the window sill of such required window is at least 23 feet above curb level;

(b)        a 15 foot yard, where the window sill of such required window is less than 23 feet above curb level;

(c)        a court with a minimum dimension of 15 feet perpendicular to such required window and 375 square feet or more in area; or

(d)        a street;

(ii)        the minimum horizontal distance between such required window opening onto a yard and any wall opposite such window on the same or another zoning lot shall be at least 15 feet;

(iii)        the area of such required window shall be no less than five percent of the floor area of the unit or quarters, and 50 percent of the area of such required window shall be openable;

(iv)        the interior dimension of the wall in which such required window is located shall be no less than 12 feet in width;

(v)        the average width of such unit or quarters shall be no less than 14 feet; and

(vi)        not less than two-thirds of the floor area of the unit or quarters shall have a floor-to-ceiling height of nine feet or more.