In addition to permitted conditional uses and exceptions hereinbefore specified, the Board of Zoning Appeals shall have the power to permit the following conditional uses and exceptions:
(a) Nonconforming Uses; Substitution. The substitution of a nonconforming use existing as of the date of passage of this Ordinance by another nonconforming use, if no structural alterations, except those required by law or resolution, are made; provided, however, in an R District no change shall be authorized by the Board to any use which is not a permitted or conditional use in any R District, and in a B District no change shall be authorized to any use which is not a permitted or conditional use in any B District.
(b) Nonconforming Uses, Extension. The extension of a nonconforming building upon the lot occupied by such building, or on an adjoining lot; provided that such lot was under the same ownership as the lot in question at the time the use of such building became a nonconforming use; provided that the value of such extension shall not exceed in all twenty-five percent of the assessed valuation for tax purposes of the existing building devoted to a nonconforming use, and that such extension shall be within a distance of not more than fifty feet of the existing building or premises. Such extension shall in any case be undertaken before the date of passage of this Ordinance. However, the Board shall not authorize any extension or enlargement which would result in extending the useful life of a nonconforming building, or which would result in violation of the provisions of this Zoning Ordinance with respect to any adjoining premises.
(c) Extension of Use on Border of District. The extension of a use or building into a more restricted district immediately adjacent thereto, but not more than twenty-five feet beyond the dividing line of the two districts, under conditions as will safeguard development in the more restricted district.
(d) Conditional Industrial Uses. In parts of any M-2 District that are more than 600 feet distant from any R District, and more than 200 feet from every other district except an M-1 District, any of the industries or uses listed in Section 1153.02
. In permitting such uses, the Board may require the installation, operation and maintenance in connection with the proposed use of such devices or such methods of operation as may, in the opinion of the Board, be reasonably required to prevent or reduce fumes, gas, dust, smoke, odor, water-carried waste, noise, vibration or similar objectionable features, and may impose such conditions regarding the extent of open spaces between such industries or uses and surrounding properties as will tend to prevent or reduce the harm which might otherwise result from the proposed use of surrounding properties and neighborhoods.
(e) Temporary Structures and Uses. The temporary use of a structure or premises in any district for a purpose or use that does not conform to the regulations prescribed elsewhere in this Zoning Ordinance for the district in which it is located, provided that such use is of a temporary nature and does not involve the erection of a substantial structure. A zoning certificate for such use shall be granted in the form of a temporary and revocable permit, for not more than a twelve month period subject to such conditions as will safeguard the public health, safety, convenience and general welfare.