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Exhaust Requirements
31
M414038
© Copyright, Alliance Laundry Systems LLC – DO NOT COPY or TRANSMIT
Individual Venting
For maximum efficiency and performance, it is
preferred to exhaust tumbler(s) individually to
the outdoors.
IMPORTANT: At no point may the cross area of
installed venting be less than the cross area of the
exhaust thimble of the tumbler.
The maximum allowable length of venting of the same
diameter as the exhaust thimble is 14 feet (4.3 meters)
and two 90° elbows or equivalent. If the equivalent
length of a duct required for an installation exceeds the
maximum allowable equivalent length, the diameter of
a round duct must be increased by 10% for each
additional 20 feet (6.1 meters). Cross section area of a
rectangular duct must be increased by 20% for each
additional 20 feet (6.1 meters). Refer to Table 5 to
determine equivalent venting:
With the tumbler in operation, airflow at any point in
the duct should be at least 1200 feet per minute
(366 meters per minute) to ensure that lint remains
airborne. If 1200 feet per minute cannot be
maintained, schedule a regular inspection and cleaning
of the ductwork.
Manifold Venting
While it is preferable to exhaust tumblers individually
to the outdoors, a main collector duct may be used if it
is sized according to Figure 10. This illustration
indicates minimum diameters, and should be increased
if collector length exceeds 20 feet (6.1 meters).
Manifold duct may be rectangular in cross section, as
long as area is not reduced. Provisions should be made
for lint removal and cleaning of duct.
Manifold duct must be tapered, as shown in Figure 9.
Individual tumbler ducts must enter manifold duct at a
45° angle in the direction if airflow.
Never connect a tumbler duct at a 90° angle to a
collector duct. Doing so will cause excessive back
pressure, resulting in poor performance. Never
connect two tumbler exhaust ducts directly across
from each other at the point of entry to manifold
duct.
Figure 9
Exhaust system must be designed so static back
pressure measured 12 inches (305 mm) from exhaust
thimble does not exceed maximum allowable pressure
specified on installation sticker on rear of tumbler.
This must be measured with all tumblers running that
are vented into collector.
With the tumbler in operation, airflow at any point in
the duct should be at least 1200 feet per minute
(366 meters per minute) to ensure that lint remains
airborne. If 1200 feet per minute cannot be
maintained, schedule a regular inspection and cleaning
of the ductwork.
Duct Diameter
Equivalent Length
of Straight Duct
10 in. (254 mm)
12 in. (305 mm)
14 in. (356 mm)
16 in. (406 mm)
18 in. (457 mm)
One 90° elbow = 11.6 ft. (3.5 m)
One 90° elbow = 14 ft. (4.3 m)
One 90° elbow = 16 ft. (4.9 m)
One 90° elbow = 18.7 ft. (5.7 m)
One 90° elbow = 21 ft. (6.4 m)
Equivalent Length (ft.) = 1.17 x Duct Diameter (in.)
Table 5
Example: A 12 inch diameter duct’s equivalent length
of 14 feet of duct and two 90° elbows is:
Equivalent Length: = 14 ft. + (2) 90° elbows
= 14 ft. + 14 ft. + 14 ft.
= 42 ft. (12.8 m)
T438I