Other protective devices or structures may be used, providing such structures and protective devices have been previously approved by the Board of Appeals of the City. The Board of Appeals shall determine that the degree of protection provided by the substitute devices or structures is not less than the protection afforded by the fence, gate, and self-latching and self-closing device described elsewhere in this chapter. (Ord. 2724 § 1, 1998; Ord. 1049 § 2; prior code § 29.10).