(1)The external walls of every room intended for habitation in a masonary building to be used for residential purpose shall be provided with windows for the admission of light and air. The superficial area occupied by such windows shall not be less than one fourth of the floor space of the room.(2)Every opening abutting on any open space shall be so located that the sill of such opening shall not be less than 2 feet 6 inches above the level of the floor from which such opening is accessible.(3)Every staircase in a building shall be provided with one or more windows of at least two square feet in area. In this case of a building of more than two stories the staircase shall have a window in each storey.
