Sound pressure level and frequency / tone

HutchNet Wireless LLC
One East Ninth, Suite 108 ● Hutchinson, KS 67501
Office Ph. 620.259.WIFI [9434]
Email: [email protected] ● www.hutchnetwireless.com
Sound pressure level and frequency / tone response evaluation.
Report Date: 04/27/11
Client:
TLG WindPower
6816 W. 82nd Ave.
Nickerson, KS 67561
PH: 620-422-3700
Service Description:
Sound Level & Tone Analysis
Subject: TLG-1800-GT
Wind Turbine
Survey date(s): 4/22, 4/23, 4/27/2011
Purpose:
HutchNet Wireless LLC is to provide third party on site survey and analysis of a wind turbine
located at 6816 W. 82nd Avenue Nickerson, KS. The test location is a rural setting and the
turbine itself is located 152 feet from a paved road with a posted speed limit of 55 mph.
(Distance shown in Exhibit A test environment)
Purpose of the test is to determine the audible levels (dBA) also referred to as SPL (Sound
Pressure Level) emitted from the turbine at defined distances. The client indicated that he
wanted advanced testing preformed to include resonant frequencies for structural harmonics in
addition to audible level / dBA, but the main focus of the test will be dBA. At the clients
request testing cannot be conducted unless the wind speed reaches at least 20 mph during
gusts.
Test Subject:
The subject being analyzed is a wind turbine manufactured by TLG WindPower Products with a
model ID of TLG-1800-GT. It has three blades with a total diameter of 6.25 feet. Blade material
is aluminum alloy. According to the manufacturer this is a small scale home wind turbine that is
directly connected to the utility grid with a peak output rating of 2.1Kw.
(Images of test subject will appear in Exhibit A test environment.)
“Locally Owned, Locally Supported Wi-Fi Internet and Personal Computer Service”
www.hutchnetwireless.com
Survey Equipment:
Digital Camera
Kaindl Electronics Windtronic 2 handheld Anemometer to reference wind speed
Phonic: Model PAA2, Serial #OGA0H80069, 31 band @ 1/3 octave frequency and sound level
audio analyzer. (Windscreen used for test)
The meter was calibrated prior to the test using a ND9 1 kHz IEC942 calibrator.
The Acoustical range for this test is full spectrum (20 Hz ~ 20 KHz) @ 32 ms (millionth of a
second) sample rate with “A” scale weighting to match human ear response. “A” scale = dBA
Reference of terms covering Exhibit B survey results:
Frequency: Range of frequency monitored in Hz or KHz
ms: millionth of a second, also referred to as milliseconds
Ambient Sound: base reading of all sound levels measured from all environmental sources with
turbine stopped.
HutchNet Wireless LLC
dBA: decibels measured using “A” weighing scale (ANSI standard)
Wind Speed: approximate range of wind speed in (mph) at time span of test
Distance: distance from base of subject tower in (feet) at point of test
Time: Length of time in (minutes) the turbine was monitored
N/A: not applicable
2
Exhibit A
Test Environment
nd
The location is approximately a 1.5 acre rural parcel on 82 Ave which is referred to by locals as the old
highway and it has traffic present. However, testing was able to be completed during times of no traffic.
Tree and wildlife noises were present throughout the test process and may cause some of the readings to
be slightly higher than actual due to wind noise from pine trees and the singing of various birds in close
proximity to the turbine and should be considered when viewing dBA in Exhibit B survey results.
HutchNet Wireless LLC
View of test subject from paved road (without zoom)
Mounted on tallest pole
3
HutchNet Wireless LLC
Image above taken at the end of the ambient test and displays all sounds including traffic.
4
Exhibit B
Survey Results
Sound Pressure Levels (dBA) of the TLG-1800-GT
Dates of test: 4/22/11, 4/23/11
Wind Speed 5~12 mph
Frequency
Distance
Time
Wind Speed
dBA
20~20
0
2 min
~8-10 mph
35
20~20
33’
3 min
~5-10 mph
33.2
20~20
75’
2 min
~10-12 mph
N/A
20~20
100’
2 min
~8-10 mph
N/A
20~20
150’
2 min
~10-12 mph
N/A
Ambient Sound
Ambient Sound
5 min
N/A
32-42
Sound Pressure Levels (dBA) of the TLG-1800-GT
Date of test: 4/27/11
Wind Speed 12~24 mph
Frequency
Distance
Time
Wind Speed
dBA
20~20
0
2 min
~18-24 mph
43 – 44.1
20~20
33’
2 min
~16-24 mph
42.5 – 43
20~20
75’
1 min
~12-19 mph
41 – 42.2
20~20
100’
1 min
~16-22 mph
N/A
20~20
150’
1 min
~22-24 mph
N/A
Ambient Sound
Ambient Sound
5 Min
N/A
50
HutchNet Wireless LLC
Resonant Frequency of the TLG-1800-GT
Tower Structural Design Data
5
Frequency below indicates the range of emitted frequency at test point
Wind Speed
Distance
Time
Frequency
~8 mph
Tower Contact
90 Seconds
400Hz
~12, ~18, ~22 mph
Tower Contact
2 Minutes
1.6KHz
Note
Intermittent