D.   Institutions of a religious, educational, or philanthropic nature, including libraries.† 13

      E.   Hospitals, day nurseries, nursing and convalescent homes, clinics, excepting animal hospitals.†

      F.   Private clubs, fraternities, sororities, and lodges, excepting those the principal activity of which is a service customarily carried on as a business.†

   2.   Accessory Uses.

      A.   Accessory uses permitted in the R-1 District.

      B.   Other accessory uses and structures, not otherwise prohibited, customarily accessory and incidental to any permitted principal use, including an indirectly lighted, non-flashing sign not to exceed one square foot for every five feet of frontage of property occupied by the use in question.

      C.   Storage garages where the lot is occupied by multiple dwellings, hospital, or institutional buildings.

   3.   Height Regulations. No principal building shall exceed three stories or 45 feet in height at the required front, side, and rear yard lines, but above the height permitted at said yard lines, two feet may be added to the height of the building for each one foot that the building or portion thereof is set back from the required yard lines, except as further provided in Section 170.25.

   4.   Lot Area, Frontage, and Yard Requirements - R-2. The following minimum requirements shall be observed, subject to the modified requirements contained in Section 170.25.