Sample Power Plant Noise
Some representative power plant noise
control projects where we've been the primary acoustical
Goals: 49 dB(A) at nearest residence located across road.
The project was a 1,100 MW
combined cycle power
plant based on four General Electric Frame 7FA GTG,
HRSGs with duct firing, and two General Electric model D11 steam
turbine generators. The facility cooling was through a multi-cell wet
Power Acoustics, Inc was involved at all stages starting with a
"green field" plant developer and ending with community noise testing
the facility's completion. At early stages, we obtained
ambient sound measurements and performed preliminary noise modeling
analysis. The early analysis enabled us to set sound level goals
that assured negligible community
response. We later performed a facility
acoustical design study for Duke-Fluor Daniel and completed the project
with sound level compliance testing.
The facility coexists within the community with no known complaints
from any nearby neighbors.
120 MW Gas
The gas turbine had a poorly performing inlet silencing system
do to a bad batch of materials used by the OEM.
Power Acoustics, Inc performed an evaluation of the site and found
tonal noise sources and sound levels in excess of 110 dB(A) in front of
the inlet filter house. Complicating the issue was an
ducting arrangement that impeded flow from entering one side of the
existing vertically aligned silencer. Power Acoustics designed a
retrofittable muffler rotated 90 degrees from the original to improve
distribution. The retrofit was located in a small section of
empty ducting. Although the
retrofit silencer was approximately 1/3 the length of the original, it
provide approximately 20 dB(A) of additional insertion
loss and reduced sound levels to an acceptable level.
Power Acoustics, Inc. has designed approximately 350 successful inlet
or exhaust silencers or mufflers for both end users, such as the
utilities, and silencer manufacturers
such as C&W Fabricators, an original equipment supplier for most
major gas turbine manufacturers such as GE and Siemens and
800 MW CC Power
Goal: 70 dB(A) at 90 ft from equipment.
This facility was in the middle of an industrial park
with no residential or commercial zones within several thousand
designed the least expensive noise control available consisting of a
sound wall adjacent to the property line - just to meet the local noise
The facility achieved the requirements with a 1 dB(A) margin.
1.6 MW Diesel
Frequency dependent sound pressure level requirements were
imposed at the nearest residential neighbors - located few hundred feet
away. Criteria were set for all octave band frequencies between 31.5 Hz
and 8000 Hz.
Sometimes the plant is just too
close to the neighbors. We evaluated this facility and developed
a plan to achieve the noise goals which would require extensive
modifications and silencing to all eight units.
450 MWPeaker Units
Frequency dependent sound pressure levels were
imposed including a low frequency limit of 69 dB at 31.5 Hz at the
nearest residential neighbors - located approximately 800 ft away.
Additional criteria were set for all frequencies between 31.5 Hz and
Power Acoustics, Inc was involved at the power plant
stages by evaluating the design for Harza Engineering. The
critical low frequency sound pressure levels were achieved at all
residential locations. Although ignored by many acoustical
low frequency noise, or infra sound, can be observed as vibration in
homes and is often the primary complaint from neighbors located near
gas turbine installations.
with our customers to solve problems before the plant is built and when
the rules change.
Power Acoustics, Inc. typical involvement is related to projects in
need of special use
permits or zoning approvals. However, we also perform
work in eminent domain issues, criminal cases, and various other
situations requiring legal support and acoustical expertise.
Our most notable case as an expert witness
was related to an
existing power generation facility that was located in a fully
industrial location in 2004. An empty property adjacent to the
power plant site was slated for use as a balefill operation.
However, the balefill property was later sold to a housing developer
wanting to build homes several hundred feet from the power
plant. Working for the utility's lawyers, we successfully
testimony and sound test data that supported a modification to the
existing state noise
regulations. Although the state's attorney general opposed the
petition, the pollution control board accepted our clients request and
issued a revision to the noise regulation requirements for the client's
Prior to this ruling, no changes had been issued by the state since