Notwithstanding the other provisions of this Chapter, in all districts, an enlargement, extension, conversion, change of use or other alteration to a building that furthers the design and construction of facilities for accessibility for individuals with disabilities or furthers building safety by greater conformance with the most recent New York City Construction Codes, may create a new non-compliance or increase the degree of a non-compliance, provided that increases to existing non-compliances, or the creation of new non-compliances, with regard to:

1. maximum floor area ratio shall not exceed ten percent of the existing floor area, or 1,000 square feet, whichever is less;
2. required open space, yards, rear yard equivalents, or courts, as applicable, shall not diminish the size of the required or existing open area, as applicable, by more than 20 percent, and no further encroachment to a non-complying yard shall be closer to a lot line than an existing building or other structure on the zoning lot; and
3. the permitted height and setback of a building or other structure, shall be limited to one story or 15 feet, whichever is less.

Allowances for permitted obstructions may be applied to an existing building, including as modified pursuant to the provisions of this Section.