HomeMy WebLinkAboutHighlands Generator Sound Testing Results.msgHi J.D.,
Below are a couple of sections from the technical memorandum that we are in the process of finalizing. The first section identifies the locations where sound level measurements were
taken. The second section includes the testing results and a brief summary. Please let me know if you have any questions or need additional information. The technical memorandum
is in the final proofing and review stage and will be ready to send to you this week.
Testing locations
* West property – This recording location was at the property line of the reservoir property and the property immediately to the west at a distance of approximately 120 feet from the
generator. The sound levels were taken 2 feet from the edge of the road.
* South Property – This recording location was at the north edge of the property that is across the street from the reservoir property. The recording was taken half way between the
property’s chain link fence and the edge of the road. This is approximately 55 feet from the generator.
* South edge of reservoir Property - The location is in the driveway entrance to the reservoir site and 2 feet from the edge of the street. This is approximately 100 feet from the
generator.
* East property – This recording location was at the property line of the reservoir property and the property immediately to the east at a distance of approximately 225 feet from the
generator. The sound levels were taken 2 feet from the edge of the road.
Figure 1- Sound Level Recording Locations
generator sound level testing results
Table 1 below summarizes the results of the generator and load bank sound level testing. Also included are the testing results from the previously installed generator. Table 1 summarizes
the sound levels in decibels dB(A) for the previously used generator on the left and the new permanent generator on the right and are further reviewed in the following summary.
Table 1
Measured dB(a) at Neighboring Property Lines
Property Line
Previous Generator
dB(A) measured
Current Generator
dB(A) measured
Generator Loading
Unknown
Ambient Noise
25% Loaded
50% Loaded
75% Loaded
100% loaded
West property
67
52 – 68 depending on traffic
63
64
65
65
South edge of Reservoir property
N/A
69
71
71
72
South property
71
65
66
67
67
East property
57
53
55
56
56
Summary
The sound level for the current generator measures between 1dB and 4dB quieter than the previously installed trailer mounted generator depending on the measuring location. The measured
values are also in line with the advertised sound attenuation specifications from Kohler. Based on the measured results of the new generator installation in comparison to the previous
installation, the sound level impact to the neighboring residences has been reduced from where it was prior to constructing the generator improvements.
Thank you,
Chris Roberts, PE | RH2 Engineering
Project Manager
22722 29th Drive SE, Suite 210
Bothell, WA 98021
P: 425.951.5358
C: 206.437.2878
croberts@rh2.com
www.rh2.com <http://www.rh2.com/>