The building official of the city shall have the powers and duties prescribed for the "building official" by the city's building code; provided, that his powers and duties may be exercised by his authorized representatives under his supervision and control. The term "building inspector", whenever used in this code or the ordinances of the city, means the building official. The terms "electrical inspector", "plumbing inspector", and "gas inspector", wherever used in the ordinances of the city, also each refer to and mean the building official, unless a separate electrical inspector, plumbing inspector, or gas inspector is appointed by the mayor and city council. (1990 Code § 5-104)