As used in this article:

(a) "License" means a valid and current license issued by the Commissioner of Labor in accordance with the provisions of this article.

(b) "Journeyman plumber" means a person qualified by at least eight thousand hours of plumbing or related experience and who is competent to instruct and supervise the work of a plumber in training.

(c) "Master plumber" means a person with at least twelve thousand hours of plumbing work experience and who is competent to design plumbing systems, and to instruct and supervise the plumbing work of journeyman plumbers, and plumbers in training.

(d) "Plumber in training" means a person with interest in and an aptitude for performing plumbing work but who alone is not capable of performing plumbing work, and who has fewer than eight thousand hours of plumbing experience.

(e) "Plumbing" means the practice, materials and fixtures utilized within a building in the installation, extension and alteration of all piping, fixtures, water treatment devices, plumbing appliances and appurtenances, in connection with sanitary drainage or storm drainage facilities; the plumbing venting systems; medical gas systems; fuel oil and gas piping for residential, commercial and institutional facilities; backflow preventers; and public or private water supply systems, as defined by the state building code.

(f) "Single family dwelling" means a building which is occupied as, or designed or intended for occupancy as, a single residence for one or more persons.