Page 635 - 2018_IRC

FUEL GAS

4. Floor construction. Floor furnaces shall not be installed accordance with this code. Fire dampers shall not be installed
in concrete floor construction built on grade. in clothes dryer exhaust duct systems.
5. Thermostat. The controlling thermostat for a floor fur- G2439.3 (614.4) Exhaust installation. Exhaust ducts for
nace shall be located within the same room or space as clothes dryers shall terminate on the outside of the building
the floor furnace or shall be located in an adjacent room and shall be equipped with a backdraft damper. Screens shall
or space that is permanently open to the room or space not be installed at the duct termination. Ducts shall not be
containing the floor furnace. connected or installed with sheet metal screws or other fas-
G2437.3 (609.3) Bracing. The floor around the furnace shall teners that will obstruct the flow. Clothes dryer exhaust ducts
be braced and headed with a support framework designed in shall not be connected to a vent connector, vent or chimney.
accordance with Chapter 5. Clothes dryer exhaust ducts shall not extend into or through
ducts or plenums. Clothes dryer exhaust ducts shall be sealed
G2437.4 (609.4) Clearance. The lowest portion of the floor in accordance with Section M1601.4.1.
furnace shall have not less than a 6-inch (152 mm) clearance
from the grade level; except where the lower 6-inch (152 G2439.3.1 (614.4.1) Exhaust termination outlet and
mm) portion of the floor furnace is sealed by the manufac- passageway. The passageway of dryer exhaust duct termi-
turer to prevent entrance of water, the minimum clearance nals shall be undiminished in size and shall provide an
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shall be not less than 2 inches (51 mm). Where such clear- open area of not less than 12.5 square inches (8065 mm ).
ances cannot be provided, the ground below and to the sides G2439.4 (614.5) Dryer exhaust duct power ventilators.
shall be excavated to form a pit under the furnace so that the Domestic dryer exhaust duct power ventilators shall be listed
required clearance is provided beneath the lowest portion of and labeled to UL 705 for use in dryer exhaust duct systems.
the furnace. A 12-inch (305 mm) minimum clearance shall The dryer exhaust duct power ventilator shall be installed in
be provided on all sides except the control side, which shall accordance with the manufacturer’s instructions.
have an 18-inch (457 mm) minimum clearance.
G2439.5 (614.6) Makeup air. Installations exhausting more
G2437.5 (609.5) First-floor installation. Where the base- than 200 cfm (0.09 m /s) shall be provided with makeup air.
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ment story level below the floor in which a floor furnace is Where a closet is designed for the installation of a clothes
installed is utilized as habitable space, such floor furnaces dryer, an opening having an area of not less than 100 square
shall be enclosed as specified in Section G2437.6 and shall inches (0.0645 m ) for makeup air shall be provided in the
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project into a nonhabitable space. closet enclosure, or makeup air shall be provided by other
approved means.
G2437.6 (609.6) Upper-floor installations. Floor furnaces
installed in upper stories of buildings shall project below into G2439.6 (614.7) Protection required. Protective shield
nonhabitable space and shall be separated from the nonhabit- plates shall be placed where nails or screws from finish or
able space by an enclosure constructed of noncombustible other work are likely to penetrate the clothes dryer exhaust
materials. The floor furnace shall be provided with access, duct. Shield plates shall be placed on the finished face of all
clearance to all sides and bottom of not less than 6 inches framing members where there is less than 1 / inches (32 mm)
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(152 mm) and combustion air in accordance with Section between the duct and the finished face of the framing mem-
G2407. ber. Protective shield plates shall be constructed of steel, shall
have a minimum thickness of 0.062 inch (1.6 mm) and shall
extend not less than 2 inches (51 mm) above sole plates and
SECTION G2438 (613) below top plates.
CLOTHES DRYERS
G2438.1 (613.1) General. Clothes dryers shall be tested in G2439.7 (614.8) Domestic clothes dryer exhaust ducts.
Exhaust ducts for domestic clothes dryers shall conform to
accordance with ANSI Z21.5.1/CSA 7.1 and shall be the requirements of Sections G2439.7.1 through G2439.7.6.
installed in accordance with the manufacturer’s instructions.
G2439.7.1 (614.8.1) Material and size. Exhaust ducts
shall have a smooth interior finish and shall be constructed
SECTION G2439 (614) of metal not less than 0.016 inch (0.4 mm) in thickness.
CLOTHES DRYER EXHAUST The exhaust duct size shall be 4 inches (102 mm) nominal
in diameter.
G2439.1 (614.1) Installation. Clothes dryers shall be
exhausted in accordance with the manufacturer’s instructions. G2439.7.2 (614.8.2) Duct installation. Exhaust ducts shall
Dryer exhaust systems shall be independent of all other sys- be supported at 4-foot (1219 mm) intervals and secured in
tems and shall convey the moisture and any products of com- place. The insert end of the duct shall extend into the
bustion to the outside of the building. adjoining duct or fitting in the direction of airflow. Ducts
shall not be joined with screws or similar fasteners that pro-
G2439.2 (614.2) Duct penetrations. Ducts that exhaust 1
clothes dryers shall not penetrate or be located within any trude more than / inch (3.2 mm) into the inside of the duct.
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fireblocking, draftstopping or any wall, floor/ceiling or other Where dryer exhaust ducts are enclosed in wall or ceiling
assembly required by this code to be fire-resistance rated, cavities, such cavities shall allow the installation of the duct
unless such duct is constructed of galvanized steel or alumi- without deformation.
num of the thickness specified in the mechanical provisions G2439.7.3 (614.8.3) Transition ducts. Transition ducts
of this code and the fire-resistance rating is maintained in used to connect the dryer to the exhaust duct system shall

610 2018 INTERNATIONAL RESIDENTIAL CODE ®
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