Trane Axiom GEH006, Руководство пользователя

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36 WSHP-PRC001-EN
Duct Design for Noise Control
Proper acoustics are often a design
requirement. Most of the problems
that are associated with HVAC
generated sound can be avoided
by properly selecting and
locating the components of the
system. Acoustical modeling
should be used to find the
lowest cost design to meet a
specific sound
requirement, however,
there are some general do’s
and don’ts that should be
observed.
Figure 46 shows a supply air duct
that is placed too close to the blower
to provide substantial noise
attenuation. It also, represents the
effects on sound that a short supply
branch connected to the discharge
may produce. Avoid these forms of
connections when designing ductwork
where noise attenuation is critical.
The following suggestions will reduce
the amount of sound that reaches the
ocupied space:
• Design the duct run with two
90-degree turns
• Line the first 5 feet of the
supply trunk
• Line elbows and transi-
tion pieces, as well as a
short distance upstream
and downstream of the
fittings
• Use flexible connections to iso-
late vibrations
• Provide multiple discharges
• Keep duct velocity low
See
Figure 47
for a positive represen-
tation of supply duct work design for
noise attenuation on units over 1 1/2
tons.
Application
Considerations
Figure 47: Desired supply-air ducting
Figure 46: Improper supply-air ducting