Section 3. Except as provided herein relative to consolidated authorities, each industrial development financing authority shall be governed by a board of five directors. Said directors shall be appointed in a city by the mayor or by the city manager in a Plan D or Plan E municipality, subject, in either case, to confirmation by the city council, and in a town by the board of selectmen; provided, that the directors originally appointed shall be appointed to serve for terms of one, two, three, four and five years, respectively, measured in each case from the April first next following their original appointment. At least one director shall be experienced in financial matters, one in real estate matters and one in town or city government. In the case of a consolidated industrial development financing authority, there shall be five directors for each constituent municipality appointed as herein before provided.

Membership on the board of directors of an industrial development financing authority shall be restricted to residents of the municipality or in case of a consolidated authority to residents of the constituent municipality from which they are appointed. No person shall be disqualified from serving as a director by reason of holding any other appointive or elective office in the municipality. For the purposes of chapter two hundred and sixty-eight A, the directors of such authority shall be deemed to be special municipal employees.

Upon the expiration of the term of any director of an authority, his successor shall be appointed in like manner for a term of five years, or in the case of an appointment made to fill a vacancy, for the unexpired term. Any director shall continue in such capacity upon the expiration of his term until his successor is appointed and qualified.

Whenever the membership of the board of directors of an authority is changed, by appointment, resignation or removal, a certificate and duplicate certificate to that effect shall promptly be filed as provided in section two upon the appointment and qualification of the original directors. A duplicate certificate so filed with the state secretary shall be conclusive evidence of the change in membership of the authority referred to therein.