Every room in which persons live, sleep, work or congregate shall have at least one window or ventilating skylight opening directly either upon a street or upon a rear yard, front yard, inner court or outer court located upon the same lot and conforming to the requirements prescribed by this chapter as to the minimum area and least dimensions. The windows or skylights opening upon such required street, rear yard, front yard, inner or outer court shall have a minimum area in each room equal to at least 1/8 of the floor area of such room. Courts, yards or other open spaces, if provided in addition to those provided by these regulations, need not be of the area and dimensions herein prescribed. No court, yard or other open space provided about any building for the purpose of complying with the provisions of this chapter shall again be used as a yard, court or other open space for any other buildings.