18
2. Single Dryer Venting
Where possible, it is suggested to provide a separate exhaust duct for each dryer. The exhaust duct
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. It is suggested that the use of 90° turns in ducting be avoided; use 30° and/or 45° angles instead.
The shape of the exhaust ductwork is not critical so long as the minimum cross section area is provided.
IMPORTANT:
Minimum duct size for a gas, electric, or steam dryer with a vertical run and not more
than three (3) elbows (including dryer connection and outside outlets) is 16-inches
(40.64 cm) for a round duct or 14-1/2” by 14-1/2” (36.83 cm by 36.83 cm) for a
square duct.
DUCT SIZE
MUST NOT BE REDUCED ANYWHERE
DOWNSTREAM OF DRYER.
IMPORTANT:
Exhaust back pressure measured by a manometer at each basket (tumbler) exhaust
duct area
must not exceed
0.3 inches (0.74 mb) of water column (W.C.).
It is suggested that the ductwork from each dryer (minimum 14-inches [35.56 cm] for a gas dryer or electric
dryer and 16-inches [40.64 cm] for a steam dryer) not exceed 20 feet (6.09 meters) with no more than three
(3) elbows (including dryer connections and outside exhaust outlets). If the ductwork exceeds 20 feet (6.09
meters) or has numerous elbows, the cross section area of the ductwork
must be
increased in proportion to
the length and number of elbows in it. In calculating duct size, the cross section area of a square or
rectangular duct
must be
increased by twenty percent (20%) for each additional 20 feet (6.09 meters).
The diameter of a round exhaust duct
should be
increased ten percent (10%) for each additional 15 feet
(4.57 meters). Each 14-inch (35.56 cm) 90° elbow is equivalent to 30 feet (9.14 meters) and each 16-inch
(40.64 cm) 90° elbow is equivalent to 36 feet (10.97 meters).
Summary of Contents for ML-130 II
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