JLA D90, Руководство по установке

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14 JLA Limited 113374 - 4
3. Multiple Dryer (Common) Venting
If it is not feasible to provide separate exhaust ducts for each dryer, ducts from individual dryers may be channeled
into a “common main duct.” 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 flow and
should be spaced at least 46-inches (116.84 cm) apart. The main
duct should be tapered, with the diameter increasing before each individual 16-inch (40.54 cm) duct is added.
IMPORTANT: When exhausted into a multiple (common) exhaust line, a back draft damper must be installed
at each dryer duct.
IMPORTANT: No more than three (3) dryers should be connected to one (1) main common duct.
The main duct may be any shape or cross-sectional area, as long as the minimum cross section area is provided. The
illustration above shows the minimum cross section area for multiple dryer round or square venting. These figures
must be increased 10 square inches (64.52 square centimeters) when rectangular main ducting is used, and the
ratio of duct width to depth should not be greater than 3-1/2 to 1. These figures must be increased in proportion
if the main duct run to the last dryer to where it exhausts to the outdoors is unusually long (over 20 feet [6.09
meters]) or has numerous elbows (more than two [2]) in it. In calculating ductwork size, the cross-sectional area of
a square or rectangular duct
must be increased twenty percent (20%) for each additional 20 feet (6.09 meters).
The diameter of a round exhaust must be increased ten percent (10%) for each additional 20 feet (6.09 meters).
Each 90° elbow is equivalent to an additional 40 feet (12.19 meters) and each 45° elbow is equivalent to an additional
20 feet (6.09 meters).