12
American Dryer Corp.
113226 - 11
CAUTION: IMPROPERLY
SIZED
OR
INSTALLED
EXHAUST
DUCTWORK CAN
CREATE
A
POTENTIAL
FIRE
HAZARD
.
The 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.
Horizontal Venting:
When single dryer venting is used, the length of ductwork from the dryer to the outside exhaust outlet
must
not
exceed
25 feet (7.62 meters). The minimum diameter of this ductwork
must be
at least 8-inches
(20.32 cm). In the case of multiple (common) dryer venting, the distance from the last dryer to the outside
exhaust outlet
must not
exceed
15 feet (4.57 meters). The shape of the ductwork is not critical as long
as the minimum cross-sectional area is provided. It is suggested that the use of 90° turns be avoided; use
30° and/or 45° angles instead. The radius of the elbows
should preferably be
1-1/2 times the diameter of
the duct. Including basket (tumbler)/dryer elbow connections or elbows used for outside protection from
the weather, no more than one (1) elbow
should be
used in the exhaust duct run. If more than one (1)
elbow is used, the cross-sectional area of the ductwork
must be
increased.
ALL
ductwork
should be
smooth inside with no projections from sheet metal screws or other obstructions, which will collect lint.
When adding ducts, the duct to be added should overlap the duct to which it is to be connected.
ALL
ductwork joints
must be
taped to prevent moisture and lint from escaping into the building. Inspection
doors
should be
installed at strategic points in the exhaust ductwork for periodic inspection and cleaning of
lint from the ductwork.
Vertical Venting:
When single dryer venting is used, the length of the ductwork from the dryer to the outside exhaust outlet
must not
exceed
15 feet (4.57 meters). The minimum diameter of this ductwork
must be
at least
8-inches (20.32 cm). In the case of multiple (common) dryer venting, the distance from the last dryer to the
outside exhaust outlet
must not
exceed
15 feet (4.57 meters). The shape of the ductwork is not critical as
long as the minimum cross-sectional area is provided. It is suggested that the use of 90° turns
be avoided; use 30° and/or 45° bends instead. The radius of the elbows
should preferably be
1-1/2 times
the diameter of the duct.
ALL
ductwork
should be
smooth inside with no projections from sheet metal
screws or other obstructions, which will collect lint. When adding ducts, the duct to be added should
overlap the duct to which it is to be connected.
ALL
ductwork joints
must be
taped to prevent moisture
and lint from escaping into the building. Inspection doors
should be
installed at strategic points in the
exhaust ductwork for periodic inspection and cleaning of lint from the ductwork.
IMPORTANT: It is recommended
that exhaust or booster fans not be used in the exhaust ductwork
system.
IMPORTANT:
Exhaust back pressure measured by a manometer in the exhaust duct
must be
no less
than 0 and
must not
exceed
0.7 inches (1.74 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
2-inches (5.08 cm) larger than the duct (all the way around).
The duct
must be
centered within this opening.
Outside Ductwork Protection
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.
