§ 139. Boiler rooms. In every dwelling the boiler or furnace of a
central heating plant shall be enclosed in a fireproof room or space and
all openings therefrom to other portions of the dwelling shall be
equipped with fireproof doors and assemblies with the doors
self-closing, except that in any dwelling three stories or less in
height, such room or space may in the alternative be enclosed with walls
or partitions constructed of fire-resistive materials and the ceiling
fire retarded.