The height of the general hospital building may exceed the maximum building height regulation of § 84-103I when authorized as a special exception by the Zoning Hearing Board subject to Article XVII of this chapter, provided that the applicant demonstrates by a clear preponderance of the evidence that the proposed structure can be serviced by existing fire-fighting equipment, and provided, further, that the height of such building shall be limited in any event to no more than eight stories or 80 feet, whichever is the lesser.