The air conditioning air distribution board shall meet at least once a month at a fixed time as determined by the city council or village board of trustees. The board shall adopt rules for the examination at such times and places of all persons who desire a certificate of competency to engage in the business of designing, installing, altering, repairing, cleaning, or adding to any air conditioning air distribution system, furnace, restaurant appliance hood and duct system, or other exhaust or intake ventilating system within the city or village and also within the area of extraterritorial zoning jurisdiction of cities of the metropolitan class.