Section 36. There shall be a board of state examiners of plumbers and gas fitters, in sections 37 and 38 called the examiners, to consist of nine members who shall be citizens of the commonwealth, one of whom shall be the commissioner of public health or his designee, one of whom shall be the commissioner of the division of occupational licensure or his designee and seven persons to be appointed by the governor, one of whom shall have at least ten years of practical experience as a master plumber, one of whom shall be a journeyman plumber with at least ten years of practical experience and who is a wage earner, one of whom shall be a sanitary or plumbing engineer, one of whom shall be a master gas fitter with at least ten years of practical experience in the field of undiluted liquefied petroleum gas and natural gas, one of whom shall be a journeyman gas fitter with at least ten years of practical experience and who is a wage earner, one of whom shall be a master or journeyman gas fitter with at least ten years of practical experience in the design and installation of liquefied petroleum gas systems and one of whom shall be a representative of the public subject to the provisions of section 9B. As the term of office of a member expires, the governor shall appoint a successor to serve for three years. The governor shall designate the chairperson of the board and may, at any time, change such designation.