A certificate authorizing the issuance of a master plumber's license shall be granted only to persons who:
(a) Have held a journeyman plumber's license for at least five years, during which period the applicant was engaged in the installation of plumbing work, or the direction thereof, or who have had training or education in a recognized trade school, college or university, and experience in the making or directing of plumbing installations under the supervision of a licensed master plumber, which is equivalent to five years' experience in the trade;
(b) Hold a license from a City which has an examining board (such as Cleveland).