Sec. 494(36). Hot air pipes and registers.
(a) All heater pipes from hot air furnaces, where passing
through combustible partitions or floors, must be covered with
standard asbestos covering. Horizontal hot air pipes leading
from furnace shall be not less than six (6) inches from any
woodwork, unless the woodwork be covered with loose fitting tin
or metal plate, or the pipe be covered with at least ½ inch of
asbestos, or in which latter case the distance from the woodwork
may be reduced to not less than three (3) inches.
(b) No hot air pipe shall be placed in a wooden stud partition
or any wooden enclosure unless it be at least five (5) feet horizontal
distance from the furnace.
(c) Every hot air furnace shall have at least one register without
valve or louvres.
(d) A register box placed in the floor over a pipeless furnace
shall have an open space around it of not less than four (4)
inches on all sides, and be supported by an incombustible border.
(e) Hot air registers placed in any woodwork or combustible
floors shall be surrounded with borders of incombustible material
not less than two (2) inches wide, securely set in place.
(f) The register boxes shall be of metal, and be double; the
distance between the two shall be not less than 1 inch, or they
may be single if covered with asbestos not less than ⅛ inch in
thickness and if all woodwork within two (2) inches be covered
with tin.
(g) Cold air ducts for hot air furnaces shall be made of incombustible
material.
