Chapter 5 Basic Duct Symbols and Drawings 105
Copyright Goodheart-Willcox Co., Inc.
5.3.7 Tees
Tee fi ttings are used at various points in the air distribution system to
direct the ductwork in two different directions. This can happen on both
the supply and return duct systems. As with other fi ttings, tees can be
fabricated with or without turning vanes, as specifi ed. Figure 5-41 shows
some commonly used supply-side tee fi ttings, as well as return-side tee
fi ttings. Tee fi ttings must be designed and sized to ensure that the total
volume of air entering the tee fi tting is equal to the total volume of air
leaving the fi tting.
B
8-B
A
8-B
D
8-B
C
8-B
Goodheart-Willcox Publisher
Figure 5-38. A and B plan views show upturning return ducts. C and D plan views
show downturning return ducts. The arrow indicates the direction of airfl ow.
A B
8-B 8-B
Goodheart-Willcox Publisher
Figure 5-39. A—Upturning exhaust duct with airfl ow from left to right. B—Downturning
exhaust duct with airfl ow from left to right.
A B
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Figure 5-40. A—Upturning round duct with airfl ow from right to left. B—Downturning
round duct with airfl ow from right to left.
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Figure 5-41. Various supply tee fi ttings
and various return tee fi ttings.
(continued)
9-L
9-G
9-K
9-M
Supply-side tee fittings
20
x
10
20
x
10
20
x
10
20
x
10
20
x
10
20
x
10