(a) All hot-air registers set in the floor of any building shall be set in a border on noncombustible material, and all floors or register boxes shall be made of sheet metal with a flange on top to fit the groove in the border. The register shall rest upon the same, and there shall also be an open space of two inches on all sides of the register box, extending from the underside of the ceiling to the border of the floor. The outside of the space shall be covered with a casing of metal and made tight on all sides.
(b) All hot-air pipes in partition walls shall be covered with asbestos material and shall have an air space of at least one inch between the pipe and the woodwork. Plaster enclosing hot-air ducts shall be upon metal lath or other approved noncombustible materials.
(Ord. 288. Passed 5-24-54.)