14
JLA Limited
113161-14
MULTIPLE DRYER (COMMON) VENTING
HORIZONTAL VENTING
If it is not feasible to provide separate exhaust ducts for each dryer, ducts for individual dryers may be channeled
into a common main duct. Each dryer is provided with a back draft damper. The individual ducts should enter the
bottom or side of the main duct at an angle not more than 45° in the direction of the airflow. No more than four (4)
dryers
should be
connected to one (1) main common duct run.
The main common duct may be any shape as long as the minimum cross-sectional area is provided. The main duct
should be
tapered with the diameter increasing before each individual 8-inch (20.32 cm) duct is added (refer to
Illus. C
and Illus. D
).
Illus. C
Multiple Dryer Venting (Horizontal)
With 8-inch (20.32 cm) Diameter Exhaust Connections at Common Duct
Horizontal venting
must not exceed
40 feet (12.2 meters) – this calculation compensates for the use of a maximum
of only one (1) elbow, which is the outside outlet protection.
NOTE:
Ductwork
should be
laid out in such a manner where allowances are made at rear area of the
dryer for removal of rear service panels or guards.
Illus. C
shows the minimum cross section area for horizontal 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.
