16
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 the ducting be avoided; use 30° 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 dryer is 16-inches (40.64 cm) for a round duct or 14-1/4"
(36.2 cm) for a square duct.
THE DUCT SIZE MUST NOT BE REDUCED
ANYWHERE DOWNSTREAM OF DRYER.
IMPORTANT:
Exhaust back pressure measured by a manometer at each basket (tumbler) exhaust
ductwork area
must not exceed
0.3 inches (0.75 mb) of water column (W.C.).
It is suggested that the ductwork from each dryer be a minimum of 16-inches (40.64 cm) for horizontal runs
with no more than one (1) elbow and 18-inches (45.72 cm) for vertical runs with no more than three (3)
elbows without exceeding 20 feet (6.1 meters) (excluding dryer connections and outside exhaust outlets). If
the duct exceeds 20 feet (6.1 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 (6.1 meters). The diameter of a round exhaust duct
should be
increased ten percent (10%) for
each additional 15 feet (4.57 meters). Each 90º elbow is equivalent to an additional 36 feet (10.97 meters),
and each 45º elbow is equivalent to an additional 18 feet (5.48 meters).
IMPORTANT
:
DO NOT
use screens, louvers, or caps on the outside opening of the exhaust
ductwork.
