19
The main common duct may be any shape so long as the minimum cross-sectional area is provided. The
main duct
should be
tapered with the diameter increasing before each individual duct is added as per the
illustrations
on
page 20
and
page 21
.
The maximum length of venting from the last dryer to where it exhausts is the following:
VERTICAL - venting run
must not exceed
8 feet (2.44 meters). This calculation compensates for the
maximum use of three (3) elbows including the two (2) elbows creating 180º (turned downward) outside
outlet.
HORIZONTAL
-
venting run
must not exceed
15 feet (4.6 meters). This calculation compensates for
the maximum use of only one (1) elbow which is the outside outlet protection.
IMPORTANT:
No more than four (4) dryers (eight [8] baskets [tumblers]) maximum
should be
connected to one (1) main common duct. Refer to the applicable section of this
manual for specific common venting size.
NOTE:
The distance between the dryer single ducts being connected to the main common duct
must
be
a minimum of 31-1/2” (80.01 cm) dryer’s width.
The ductwork
should be
laid out in such a manner where allowances are made at the rear
area of the dryer for removal of rear service panels/guards.
The
illustrations
on
page 20
and
page 21
show the minimum cross-sectional area for multiple dryer
venting. These figures
must be
increased in proportion if the main duct run from the last dryer to where
it exhausts, has numerous elbows, or is unusually long.
IMPORTANT:
For extended ductwork runs, the cross-sectional area of the duct can only be
increased to an extent. For extended ductwork runs or where numerous elbows are
used, a professional heating, venting, and air conditioning (HVAC) firm
should be
consulted for proper venting information.
NOTE:
Inspection doors
should be
installed at strategic points in the exhaust ductwork for periodic
inspection and cleaning.
a. Multiple Dryer Venting - where each basket (tumbler) is individually vented.
With multiple venting where each basket (tumbler) is vented independently (a separate exhaust is used
for each basket [tumbler]) to the common main duct, a minimum of an 8-inch (20.32 cm) diameter duct
(50 square inches [322.58 square centimeters] cross-sectional area) connection between the dryer and
common main duct is acceptable providing this duct does not exceed 8 feet (2.44 meters) in length.
IMPORTANT:
No more than four (4) dryers (eight [8] baskets [tumblers]) can be connected to one
(1) common duct vent.
