See Section 504.1, from the 2009 IMC: CLOTHES DRYER EXHAUST
504.1 Installation. Clothes dryers shall be exhausted in accordance with the manufacturer's
instructions. Dryer exhaust systems shall be independent of all other systems and shall
convey the moisture and any products of combustion to the outside of the building.
Exception: This section shall not apply to listed and labeled condensing (ductless)
clothes dryers.
From Section 504.4, from the 2009 IMC, Exhaust installation
Dryer exhaust ducts for clothes dryers shall terminate on the outside of the building and
shall be equipped with a backdraft damper. Screens shall not be installed at the duct
termination. Ducts shall not be connected or installed with sheet metal screws or other
fasteners that will obstruct the exhaust flow. Clothes dryer exhaust ducts shall not be
connected to a vent connector, vent or chimney. Clothes dryer exhaust ducts shall not
extend into or through ducts or plenums.
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