Section 71A. There shall be in the department a board to consist of not less than three examiners to be appointed by and serve at the pleasure of the commissioner. Members of said board, excepting the chairman, shall be employees of the department and shall serve without compensation for the performance of their duties as such examiners. The chairman shall be a licensed elevator engineer or a licensed elevator constructor, maintenance man and repairman having not less than ten years' practical experience in the construction, maintenance and repair of elevators. The chairman shall be paid by the commonwealth as compensation a sum of not less than $50 for each day of service performed in connection with his duties as chairman, but not more than $2,000 in a fiscal year. Each member shall receive from the commonwealth all expenses necessarily incurred by him in the performance of his duties. As used in sections seventy-one B and seventy-one C, board shall mean the board of examiners appointed under the provisions of this section.