The designating official shall issue house or premises numbers to each new residence or other structure requiring a means of separate and simple identification at the time of issuing a building permit therefor. Such numbers shall be issued for preexisting building or premises upon the request of the owner or legal occupant where no such designating number has been issued, or where the issued number conflicts with the numbering system created by this chapter, and public convenience and welfare would be promoted by such renumbering. (1961 code § 10.08.080.)