94 Print Reading for HVACR
Copyright Goodheart-Willcox Co., Inc.
This section can also be angled, as shown in Figure 5-13
to help reduce air turbulence in the ductwork, or it can
be round.
Two commonly used supply air fi ttings are the
bullhead and the tapered head, Figure 5-14. The bull-
head fi tting is popular because it is made up of two
separate, straight sections of ductwork that are joined
by the installer. It allows for adjustments and last-
minute alterations to be made on the job. The tapered
head fi tting is a variation of the bullhead supply air
fi tting. This fi tting, because of the angled sides of the
bottom duct section, reduces turbulence, but is more
expensive to fabricate and more diffi cult to modify in
the fi eld.
Single-Piece Fittings
Some other supply air fi ttings are single-piece fi ttings that are rect-
angular in shape, Figure 5-15. Some have no turning vanes, as in the
case of the 1-H fi tting, while others, such as the 1-I fi tting, have turn-
ing vanes. Turning vanes help reduce air turbulence within the duct.
1-I 1-H
Air handler
Supply air
Air handler
Supply air
Rectangular supply elbows
Without turning vanes With turning vanes
Goodheart-Willcox Publisher
Figure 5-15. Rectangular supply elbows at the air handler.
1-F 1-G
Air handler
Supply
air
Air handler
Supply
air
Bullhead
Supply air fittings
Tapered head
Goodheart-Willcox Publisher
Figure 5-14. A bullhead supply air fi tting at the air handler and a tapered head supply air fi tting at the air handler.
Supply plenum
Supply air
1-D 1-A
Goodheart-Willcox Publisher
Figure 5-13. Angled and round supply air fi ttings at the plenum.
Copyright Goodheart-Willcox Co., Inc.
This section can also be angled, as shown in Figure 5-13
to help reduce air turbulence in the ductwork, or it can
be round.
Two commonly used supply air fi ttings are the
bullhead and the tapered head, Figure 5-14. The bull-
head fi tting is popular because it is made up of two
separate, straight sections of ductwork that are joined
by the installer. It allows for adjustments and last-
minute alterations to be made on the job. The tapered
head fi tting is a variation of the bullhead supply air
fi tting. This fi tting, because of the angled sides of the
bottom duct section, reduces turbulence, but is more
expensive to fabricate and more diffi cult to modify in
the fi eld.
Single-Piece Fittings
Some other supply air fi ttings are single-piece fi ttings that are rect-
angular in shape, Figure 5-15. Some have no turning vanes, as in the
case of the 1-H fi tting, while others, such as the 1-I fi tting, have turn-
ing vanes. Turning vanes help reduce air turbulence within the duct.
1-I 1-H
Air handler
Supply air
Air handler
Supply air
Rectangular supply elbows
Without turning vanes With turning vanes
Goodheart-Willcox Publisher
Figure 5-15. Rectangular supply elbows at the air handler.
1-F 1-G
Air handler
Supply
air
Air handler
Supply
air
Bullhead
Supply air fittings
Tapered head
Goodheart-Willcox Publisher
Figure 5-14. A bullhead supply air fi tting at the air handler and a tapered head supply air fi tting at the air handler.
Supply plenum
Supply air
1-D 1-A
Goodheart-Willcox Publisher
Figure 5-13. Angled and round supply air fi ttings at the plenum.