605 ILCS 10/6

Immediately after such appointment and qualification as hereinafter provided said chairman and directors shall enter upon their duties. The directors shall biennially select a secretary, who may or may not be a director, and if not a director fix his compensation. Six directors shall constitute a quorum. No vacancy in the said Board of Directors shall impair the right of a quorum of the directors to exercise all the rights and perform all the duties of the Authority.