No room which has its floor level below grade shall be occupied as a habitable room unless it conforms to the following standards in addition to all other requirements of this Code for habitable rooms:
(a) The room shall have been originally designed and constructed or legally converted to use as a habitable room.
(b) The walls and floor enclosing the room shall be maintained in such condition as to prevent the entrance of moisture into the habitable space.
(c) All required openings for light and ventilation shall be located entirely above the average adjoining grade, provided, however, that such openings may face upon an areaway or window well where the width of such well measured perpendicular to the building wall at such opening is not less than the distance from the bottom of the window to the finished grade at such window.
(d) The height of the finished ceiling of such room above the average adjoining ground level shall be at least fifty percent of the clear ceiling height of the room. (Ord. 70-49. Passed 9-21-70.)