Defects in appointments not to invalidate acts, etc

No act or proceeding of the Board or of any its committees shall be invalid merely by reason of,- (a) any vacancy therein or any defect in the constitution thereof; (b) any disqualification of or any defect in the appointment of, a person acting as a member thereof; or (c) any member having acted or taken part in any proceedings in contravention of section 13; (d) any irregularity in its procedure not affecting merits of the case.