Every room, the ceiling of which is below grade, or which is less than four feet above the grade level, and in which one or more persons are regularly employed or congregate, shall, unless provided with windows as required for habitable rooms, be provided with an approved means of mechanical ventilation as prescribed in this Building and Housing Code, except for basements of dwellings used for domestic purposes. 
(Ord. 42-1981.  Passed 2-23-81.)