The director, subject to the disapproval of the civil service board as hereinafter provided, shall make rules to carry out the purposes of this Act, and for examinations, appointments, transfers and removals and for maintaining and keeping records of the efficiency of officers and employees, and groups of officers and employees, in accordance with the provisions of this Act, and the Director may from time to time make changes in such rules. Such rule or any amendment thereof shall take effect 30 days after written notice thereof is given to the civil service board, unless within such period the board files with the Director a written notice of its disapproval thereof.
70 ILCS 2605/4.5