98 Print Reading for HVACR
Copyright Goodheart-Willcox Co., Inc.
B E T W E E N T H E L I N E S
Selecting Takeoff Fittings
Deciding which takeoff fi tting to use is determined by the
individual who designed the system. Because different
takeoff fi ttings affect the airfl ow through the system
differently, the type or style of the takeoff fi tting should not
be changed without written approval and authorization from
the system designer.
Takeoff fi ttings can be round, square, or rectan-
gular sections of duct connected to the main supply
duct, Figure 5-21. Some takeoff fi ttings, such as those
labeled 2-F and 2-G, have scoops or dampers added
to them. These scoops and dampers extend into the
airstream to smoothly, and with less turbulence, direct
air to the branch runouts. In duct drawings, takeoff
fi ttings are easily identifi ed and labeled with their con-
struction number, Figure 5-22. Some branch takeoff
fi ttings are meant to be installed on the top of the sup-
ply duct, Figure 5-23. Other branch takeoff fi ttings are
installed on round supply ducts, Figure 5-24.
Primary or secondary
supply trunk
2-K
2-L
2-M
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Figure 5-23. Some top-of-duct mounted supply takeoff fi ttings.
Primary or secondary
supply trunk
2-A
2-D
2-E
2-F
2-G
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Figure 5-21. Some commonly used supply takeoff fi ttings.
2-A 2-D 2-E 2-F 2-G
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Figure 5-22. How supply takeoff fi ttings appear in duct drawings.