The location and height above curb level of the street wall of any development or enlargement shall be as shown in the District Plan (Appendix A). However, if a development or enlargement is adjacent to one or more existing buildings fronting on the same street line, the street wall of such development or enlargement shall be located neither closer to nor further from the street line than the front wall of the adjacent building which is closest to the same street line.

Street wall recesses are permitted below the level of the second story ceiling for subway stair entrances required under Section 118-50 (OFF STREET RELOCATION OF A SUBWAY STAIR WITHIN THE SPECIAL UNION SQUARE DISTRICT). Such recesses shall be no longer than 15 feet and no deeper than eight feet or the width or length of the relocated subway stair, whichever is greater.

Street wall recesses are also permitted below the level of the second story ceiling for building or store entrances only.

A sky exposure plane of 2.5 to 1 shall begin at a height above curb level of 125 feet on all streets within the Special District, except that on a narrow street beyond 100 feet from any street line opposite a public park or from the intersection of such narrow street with a wide street, the sky exposure plane shall begin at a height above curb level of 85 feet.

No development or enlargement shall penetrate such sky exposure plane except pursuant to Section 33-45 (Tower Regulations). However, Section 33-45 shall not be applicable to any portion of a building located within 100 feet of a street line opposite a public park.

However, energy infrastructure equipment and accessory mechanical equipment shall be permitted obstructions above such height limits, subject to the provisions of Section 33-42.