In C2-1, C2-2, C2-3, C2-4, C4-1, C4-2, C4-3, C4-4, C4-5D, C7, C8-1, C8-2, C8-3, M1-1, M1-2, M1-3, M2-1, M2-2 or M3-1 Districts, for public parking garages with a total of 150 spaces or less, the Board of Standards and Appeals may permit floor space on one or more stories to be exempted from the definition of floor area as set forth in Section 12-10 (DEFINITIONS), provided that all floor space so exempted is located not more than 23 feet above curb level and provided that the following findings are made:

(a)        that the additional floor space permitted is needed in order to prevent excessive on-street parking demand and relieve traffic congestion; and

(b)        that the hazards or disadvantages to the community at large resulting from the additional floor space permitted are outweighed by the advantages to be derived by the community therefrom under the conditions and safeguards imposed.

The Board may impose appropriate conditions and safeguards to minimize adverse effects on the character of the surrounding area.