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Since about five months after a local box factory expanded,
the company has been receiving complaints about noise. Weyerhaeuser,
formerly known as Willamette, completed a $12 million,
70,000-square-foot addition in May 2002. The plant is located at the
corner of Fifth Street and Business 55. Most of the complaints have
come from nearby residents on Third Street.
The company has been
trying for two years to eliminate the noise. "I think we're getting
closer," production manager Ed Reihl from Weyerhaeuser said. In
March of this year the company began working with city codes officer
Les Last and city attorney Bill Bates. Reihl came before the council
explaining the measures that the plant has taken so far, the results
and what is planned for the future to reduce the noise.
A device called a cyclone that is used to collect cardboard
scraps is believed to be the major noise source, Reihl said. They
have two cyclones at this time. "We've had one for 30 years," he
said, but the location of the newest cyclone and the combination of
having two is thought to be the major problem.
The cyclones are located on the roof and use high-speed blowers
to collect cardboard scraps, which are compacted, baled and then
sent to paper mills to be made into paper. This process is an
integral part of operating a box factory, Reihl said.
Six rooftop blowers connect into the cyclone, and there is a
blower underneath.
A noise consultant from Indianapolis came shortly after the first
complaint was received in the fall of 2002. One of his
recommendations was to build a muffler for each blower. That was
done at a cost of approximately $4,500. In a test of the new system
from the home of a neighbor, Lyle Ruff, no change was detected by
the human ear.
Another recommendation was to install springs below the blower to
isolate vibrations.
Springs and flexible connections were added to a blower at
$6,000. Again, there was no detectable change.
Next the company had a custom blanket designed to go around a
blower, which cost about $3,000. This, too, failed to show any
improvement.
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So it was back to the drawing board, Reihl said.
Noise readings were taken to try to determine if the source is
the blower casings, the exhaust or someplace else. "I'm convinced
that it is the exhaust from the cyclone blower that is the principal
source," he said.
On Oct 10 this year a crane was rented to rotate the main exhaust
from south to west.
Following that, noise measurements were taken. Decibels should be
down in the 40s, Reihl said. The sound was measured to the east on
Third Street at 60 decibels. Holly Drive measurements are about 46
decibels. Areas of Eighth Street are now reduced to the 40s, he
said. Problems for five homeowners are still being addressed.
At present, as the next step, another custom muffler is being
considered.
Tonals come off the blades of the blowers at 200, 400 and 600
hertz. Higher broadband noise is also produced at 800, 1,000 and
2,000 hertz. Reihl is confident that the muffler makers can help
with this if the correct tone is addressed.
Mufflers for all the small blowers or for the larger exhaust
blower are being considered, and a proposal is expected from the
muffler maker in the next couple of weeks.
If the next mufflers don't provide the needed changes, the next
consideration is to build a wall. Since that would be about $40,000,
Weyerhaeuser is trying the less expensive measures first, Riehl
said.
Mayor Beth Davis responded: "We appreciate the update and your
being here in the community. You are a big asset to us, and we know
you are working on the problem."
"If we could identify exactly what it is, it would have been
easy. But it is one of those that is difficult to figure out," Reihl
said.
[Jan
Youngquist]
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