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Project Memorandum
DRAFT – For internal discussion only. Not reviewed or approved on behalf of any party.
Attachment 3: Noise Variance Request Equipment List
Item
#
Equipment Sound level
(dBA)
Type of Construction
Work
Description of nighttime
noise/mitigation measures
1 Core drill Below 70 (at
work location)
Cut through pavement The use of this equipment
replaces the need for a jack
hammer which has higher
sound levels. This is a
mitigation measure to reduce
the noise for nighttime work.
2 Vacuum Truck 70 (at work
location) to 63
(at 100-foot
distance)
Vacuum equipment uses a
high-velocity air stream to
penetrate, expand, and
break up soil in the pothole.
The loosened chunks of
soil and rock would be
removed from the hole
through the vacuum to
reveal the buried utility.
Construction equipment sound
will likely be audible over the
background noise of the I-405
and SR 167 roadways (70-80
dBA) during nighttime hours.
The crews will implement
nighttime noise monitoring if
complaints are received. If
noise levels are observed to
be above acceptable limits,
work will halt. Work may
proceed, with monitoring, if
noise attenuation barriers are
then installed around the drill
site. A 24-hour emergency
contact will be available to
address issues or complaints.
3 Truck mounted
drill rig
95 (at work
location) to 70
(at 100-foot
distance)
Mud rotary drilling Same as above.
4 Auto-sampling
hammer
115 (at work
location) to 80
(at 100-foot
distance)
Soil sampling Same as above.
EXHIBIT 6
RECEIVED
Clark Close 08/16/2021
PLANNING DIVISION
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