Elevator penthouses and water tank modifications are as follows:
(a) Elevator penthouses, water tanks, provided no linear dimension of any such structure exceeds 50% of the corresponding street lot line frontage; fire towers, hose towers, or other public service or safety structures, can be modified where a greater height is required.
(b) Minimum requirements. All such structures above the heights otherwise permitted in the district shall not occupy more than twenty-five percent (25%) of the area of the lot and shall be distant not less than 50 feet in all parts from every lot line not a street lot line.
FRONTAGE AND YARD MODIFICATIONS