For all buildings in the Special Midtown District, except as provided in Section 81-90 (SPECIAL REGULATIONS FOR PRESERVATION SUBDISTRICT), the height and setback regulations of the underlying districts are superseded by the provisions of this Section and by the two alternate sets of regulations controlling the height and setback of buildings as set forth in Sections 81-26 (Height and Setback Regulations--Daylight Compensation) and 81-27 (Alternate Height and Setback Regulations--Daylight Evaluation), respectively. For the purposes of applying height and setback regulations, the term "buildings" shall include buildings or other structures, except if specifically stated otherwise.
For the purposes of Sections 81-25 through 81-27, inclusive, all buildings on a zoning lot shall be considered a single building. Existing portions of such buildings are referred to as an "existing building." A "new building" shall include developments, enlargements or alterations that increase the width or height of a building wall.
This Section sets forth the provisions that are common to both sets of regulations.
The common purpose of these two sets of regulations is to offer maximum design flexibility while setting reasonable but firm standards to protect access of light and air to public streets and adjacent buildings.
This purpose is implemented by the two alternate sets of regulations, which are based on two distinct approaches. Both sets are concerned with daylight at street level.
The daylight compensation regulations require any building generally to be built within a sky exposure curve which relates required setbacks to building heights. Within limits, the buildings may encroach outside the curve but only if extra setbacks or recesses provided elsewhere on the same street frontage of the zoning lot compensate for the encroachment. In the regulations, the sky exposure curve for three street width categories is represented in each case by a table of required setbacks related to building heights.
The daylight evaluation regulations measure and evaluate portions of sky blocked by a building as viewed from specified vantage points in the street. The building is plotted on daylight evaluation charts representing the zoning lot's available daylight from specified vantage points, measured in daylight squares as defined in paragraph (b) of Section 81-272. Daylight blockage by the building is then measured to determine the building's score on each frontage and the average score for the building as a whole. The regulations specify the minimum passing scores for compliance.
Except as set forth in this Section, structures which under the provisions of Sections 33-42 or 43-42 (Permitted Obstructions) or 34-11 or 35-10 (GENERAL PROVISIONS), are permitted to penetrate a maximum height limit or a sky exposure plane shall not be permitted as exceptions to the height limitations, setback requirements or rules for the measurement of encroachments or compensating recesses set forth in Section 81-26 (Height and Setback Regulations—Daylight Compensation), nor shall they be excluded in determining daylight blockage pursuant to the provisions of Section 81-27 (Alternate Height and Setback Regulations—Daylight Evaluation).
The following shall be permitted as exceptions to the height regulations, setback requirements or rules for the measurement of encroachments or compensating recesses, set forth in Section 81-26, and shall be excluded in determining daylight blockage, pursuant to the provisions of Section 81-27:
(a) unenclosed balconies conforming to the provisions of Section 23-13 (Balconies); and
(b) exterior wall thickness, up to eight inches, where such wall thickness is added to the exterior face of a building wall existing on April 30, 2012, provided the added wall thickness has a thermal resistance (R-value) of at least 1.5 per inch. Where buildings that have added exterior wall thickness pursuant to this Section are enlarged, such enlarged portion may similarly penetrate a maximum height limit in order to align with the exterior walls of the existing building, provided such enlargement contains less floor area than the existing building, and there is no penetration of floor area above a maximum height limit.
81-253 Special Provisions for the East Midtown, Theater, Fifth Avenue, Penn Center and Preservation Subdistricts
The provisions of Sections 81-26 (Height and Setback Regulations-- Daylight Compensation) and 81-27 (Alternate Height and Setback Regulations--Daylight Evaluation) are supplemented and modified by special provisions applying in the Fifth Avenue Subdistrict, as set forth in Sections 81-81 (General Provisions) and 81-83 (Special Street Wall Requirements) or in the Theater Subdistrict as set forth in Sections 81-71 (General Provisions) and 81-75 (Special Street Wall and Setback Requirements) or in the East Midtown Subdistrict as set forth in Sections 81-61 (General Provisions), 81-66 (Special Height and Setback Requirements), inclusive, or 81-671 (Special street wall requirements), or in the Penn Center Subdistrict as set forth in Section 81-532 (Special street wall requirements).
The provisions of Sections 81-26 and 81-27 are not applicable in the Preservation Subdistrict, where height and setback is regulated by the provisions of Section 81-90 (SPECIAL REGULATIONS FOR PRESERVATION SUBDISTRICT).
In the Special Midtown District, the City Planning Commission may modify the special height and setback regulations set forth in this Chapter only in accordance with the following provisions:
Section 74-79 (Transfer of Development Rights From Landmark Sites) where development rights are transferred from a landmark site to an adjacent lot in a C5-3, C6-6 or C6-7 District, as modified by Section 81-212, and the total floor area on the adjacent lot resulting from such transfer exceeds the basic maximum floor area ratio by more than 20 percent. In such cases, the granting of a special permit by the Commission for height and setback modifications shall be in accordance with the provisions of Sections 81-266 or 81-277
Section 81-632 (Special permit for transfer of development rights from landmarks to the Vanderbilt Corridor Subarea)
Section 81-633 (Special permit for Grand Central public realm improvements)
Section 81-685 (Special permit to modify qualifying site provisions)