CAUTION: IMPROPERLY SIZED OR INSTALLED EXHAUST DUCTWORK COULD CREATE A FIRE HAZARD.
NOTE: When a dryer is exhausted separately, it is recommended that a back draft damper be installed.
NOTE: When dryers are exhausted into a multiple (common) exhaust line, each dryer must be supplied with a back draft damper.
The exhaust ductwork should be laid out in such a way that the ductwork travels as directly as possible to the outdoors with as few turns as possible. Single or independent dryer venting is recommended. When single dryer venting is used, the ductwork from the dryer to the outside exhaust outlet must not exceed 20 feet (6.09 meters). In the case of multiple (common) dryer venting, the distance from the last dryer to the outside exhaust outlet must not exceed 20 feet (6.09 meters). The shape of the ductwork is not critical as long as the minimum cross section area is provided. It is suggested that the use of 90° turns in ducting be avoided; use 30° and/or 45° angles instead. The radius of the elbows should preferably be
IMPORTANT: It is recommended that exhaust or booster fans NOT BE USED in the exhaust ductwork system.
NOTE: As per the National Fuel Gas Code, “Exhaust ducts for type 2 clothes dryers shall be constructed of sheet metal or other noncombustible material. Such ducts shall be equivalent in strength and corrosion resistance to ducts made of galvanized sheet steel not less than 26 gauge
ALL ductwork should be smooth inside with no projections from sheet metal screws or other obstructions, which will collect lint. When adding ducts, the ducts to be added should overlap the duct to which it is connected. ALL ductwork joints must be taped to prevent moisture and lint from escaping into the building. Additionally, inspection doors should be installed at strategic points in the exhaust ductwork for periodic inspection and cleaning of lint from the ductwork.
To protect the outside end of the horizontal ductwork from the weather, a 90° elbow bent downward should be installed where the exhaust exits the building. If the ductwork travels vertically up through the roof, it should be protected from the weather by using a 180° turn to point the opening downward. In either case, allow at least twice the diameter of the duct between the duct opening and the nearest obstruction (i.e., roof or ground level).
IMPORTANT: Exhaust back pressure measured by a manometer at the dryer exhaust duct area must be no less than 0 and must not exceed 0.3 inches (0.74 mb) of water column (W.C.).
NOTE: When the exhaust ductwork passes through a wall, ceiling, or roof made of combustible materials, the opening must be
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