Where the floor area to be preserved is not located within the building to be converted, such floor area must be comparable to floor area in the building to be converted.  Comparability, shown by an affidavit from a professional engineer or a registered architect, licensed under the laws of the State of New York, shall exist where the floor area to be preserved meets the following criteria:

(a)        Elevators: load and number

The load and number requirements of this paragraph shall not apply when the floor area to be preserved is located on the ground floor or has level access to a street or loading facility.

(1)        Load

Each elevator shall have a minimum load of 2,000 pounds. The total load of all elevators servicing the floor area to be preserved shall be in accordance with the following ratio:

(2)        Number

There shall be a minimum of two elevators. The number of elevators servicing the floor area to be preserved shall be in accordance with the following ratio:

Notwithstanding the above, where there is only one elevator servicing the floor area to be converted, there may be one elevator servicing the floor area to be preserved if the following exist:

(i)        the floor area to be serviced by the elevator in the building to be preserved does not exceed the floor area serviced by the elevator in the building to be converted by more than 10 percent; and

(ii)        the ratio of the volume of the elevator servicing the floor area to be preserved to the floor area to be preserved is at least 90 percent of the ratio of the volume of the elevator servicing the floor area to be converted to the floor area to be converted.

If the number of elevators required pursuant to the above ratio includes a fraction of an elevator, this fraction shall be rounded to the nearest whole number.

(b)        Floor load

The floors shall have a minimum live load capacity of 100 pounds per square foot (100 psf).

(c)        Size of floors

(1)        The floor area shall be located on floors of not less than 3,000 square feet or 50 percent of the size of the floors in the building to be converted, whichever is greater.

(2)        Floor area may not be preserved on portions of floors.

(d)        Loading facilities

The loading facilities shall be at least equal in number to those in the building to be converted.  In addition, if such building has an off-street loading dock, the building containing the floor area to be preserved must have such off-street loading facilities.

(e)        Column spacing

There shall be a minimum distance between columns of 15 feet, measured on center.  In addition, the average distance between columns shall not be less than 90 percent of the average distance between columns in the building to be converted.

(f)        Height of stories

The stories shall have an average minimum height of 10 feet.

The Chairperson of the City Planning Commission may authorize a modification of the requirements listed in paragraphs (a), (c)(1) or (d) of this Section, pursuant to the regulations of paragraph (c) of Section 15-30 (MINOR MODIFICATIONS).