The Board shall hold its first meeting upon call by the chief building official, and within thirty days following the appointment of its members. The members shall select a chairman from their own number, but not the chief building official. Such chairman shall hold office until the December 31 following, or until his or her successor has been selected. The Board shall meet upon call by the chief building official at such intervals as may be necessary for the proper performance of its duties, but in any case not less than twice a year.