The maximum length of the exhaust duct shall be 25 feet (7620 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 1502.4.4.1.
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|
Where space for a clothes dryer is provided, an exhaust duct system shall be installed. Where the clothes dryer is not installed at the time of occupancy the exhaust duct shall be capped or plugged in the space in which it originates and identified and marked “future use.”
Range hoods shall discharge to the outdoors through a single-wall duct. The duct serving the hood shall have a smooth interior surface, shall be air tight and shall be equipped with a backdraft damper. Ducts serving range hoods shall not terminate in an attic or crawl space or areas inside the building.
Single-wall ducts serving range hoods shall be constructed of galvanized steel, stainless steel or copper.
2. The underfloor trench in which the duct is installed is completely backfilled with sand or gravel; and
3. The PVC duct extends not more than 1 inch (25 mm) above the indoor concrete floor surface; and
4. The PVC duct extends not more than 1 inch (25 mm) above grade outside of the building; and
5. The PVC ducts are solvent cemented.
Ventilation systems shall be designed to have the capacity to exhaust the minimum air flow rate determined in accordance with Table 1507.3.
MINIMUM REQUIRED EXHAUST RATES FOR ONE-, TWO- AND THREE-FAMILY DWELLINGS
|AREA TO BE|
|Kitchens||100 cfm intermittent or |
25 cfm continuous
|Bathrooms— Toilet Rooms||Mechanical exhaust capacity of |
50 cfm intermittent or 20 cfm continuous