§ 174. Size of rooms. Every living room shall contain five hundred fifty cubic feet or more of air, shall be at least six feet wide at its narrowest part and shall have a minimum height of seven feet if such room is in the basement, of seven feet at all points more than six feet from the front of such room if it is on the top story, and of eight feet if on any other story, except that whenever a basement conforms to the provisions of subdivision four of section one hundred seventy-seven the living rooms in such basement may have a minimum height of six feet eight inches from the finished floor to the bottom of any beams projecting below the level of the finished basement ceiling and of seven feet to the ceiling between such beams.