Section 504 Clothes Dryer Exhaust
Clothes dryers shall be exhausted in accordance with the manufacturer’s instructions.
M1502.2Independent exhaust systems.
Dryer exhaust systems shall be independent of all other systems and shall convey the moisture to the outdoors.
Exception: This section shall not apply to listed and labeled condensing (ductless) clothes dryers.
Exhaust ducts shall terminate on the outside of the building. Exhaust duct terminations shall be in accordance with the dryer manufacturer’s installation instructions. If the manufacturer’s instructions do not specify a termination location, the exhaust duct shall terminate not less than 3 feet (914 mm) in any direction from openings into buildings. Exhaust duct terminations shall be equipped with a backdraft damper. Screens shall not be installed at the duct termination.
M1502.4.1Material and size.
Exhaust ducts shall have a smooth interior finish and be constructed of metal having a shall be 4 inches (102 mm) nominal in diameter.
Exhaust ducts shall be supported at intervals not to exceed 12 feet (3658 mm) and shall be secured in place. The insert end of the duct shall extend into the adjoining duct or fitting in the direction of airflow. Exhaust duct joints shall be sealed in accordance with Section M1601.4.1. Ducts shall not be joined with
Transition ducts used to connect the dryer to the exhaust duct system shall be a single length that is listed and labeled in accordance with UL 2158A. Transition ducts shall be not greater than 8 feet (2438 mm) in length. Transition ducts shall not be concealed within construction.
The maximum length of the exhaust duct shall be 35 feet (10 668 mm) from the connection to the transition duct from the dryer to the outlet terminal. Where fittings are used, the maximum length of the exhaust duct shall be reduced in accordance with Table M1502.4.5.1. The maximum length of the exhaust duct does not include the transition duct.
DRYER EXHAUST DUCT FITTING EQUIVALENT LENGTH
|DRYER EXHAUST DUCT FITTING TYPE||EQUIVALENT LENGTH|
|4 inch radius mitered 45 degree elbow||2 feet 6 inches|
|4 inch radius mitered 90 degree elbow||5 feet|
|6 inch radius smooth 45 degree elbow||1 foot|
|6 inch radius smooth 90 degree elbow||1 foot 9 inches|
|8 inch radius smooth 45 degree elbow||1 foot|
|8 inch radius smooth 90 degree elbow||1 foot 7 inches|
|10 inch radius smooth 45 degree elbow||9 inches|
|10 inch radius smooth 90 degree elbow||1 foot 6 inches|