"Master plumber" means a person duly certified and licensed as such and authorized to engage in the installation of plumbing, through contract or otherwise, and also in planning engineering. superintending installation, maintenance and repair with respect to plumbing in all of its branches, and as such, a master plumber is authorized to employ journeymen plumbers and plumber's apprentices and other persons necessary for the proper installation of plumbing work in accordance with the plumbing regulations and provisions of this Plumbing Code.
(1957 Code §1123.04)