The board of adjustment shall adopt rules to govern its procedures, which rules shall be in accordance with the provisions of this chapter. The board shall designate a chairman from among its members, and may, from time to time, change such designation. Meetings shall be held at the call of the chairman and at such other times as the board may determine. Any two members shall constitute a quorum. The chairman, or in his absence such other member of the board as he may designate to serve as acting chairman, may administer oaths and compel the attendance of witnesses. All meetings of the board shall be open to the public. The board shall keep a full and accurate record of all proceedings, of all documents filed with it, and of all orders entered, which shall be filed in the office of the board and shall be a public record.