Annex A4.1 |
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Calculation
of Noise Level Due to Operation of Wind Turbine |
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NSR Location: |
Hei Ling Chau
Correctional Institution (N1) |
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Horizontal Distance= |
740 |
m |
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Vertical Distance= |
40 |
m |
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Slant Distance= |
741 |
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Frequency,
Hz |
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25 |
31.5 |
40 |
50 |
63 |
80 |
100 |
125 |
160 |
200 |
250 |
315 |
400 |
500 |
630 |
800 |
1000 |
1250 |
1600 |
2000 |
2500 |
3150 |
4000 |
5000 |
6300 |
8000 |
10000 |
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0.0 |
SWL(1), dB(A) |
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66.5 |
68.8 |
72.2 |
78.9 |
78.3 |
80.6 |
84.9 |
84.9 |
87.3 |
91.2 |
90.5 |
92.5 |
92.5 |
93.4 |
94.7 |
93.8 |
93.5 |
93.4 |
93.6 |
91.5 |
89.5 |
87.7 |
86.8 |
83.5 |
76.5 |
69.8 |
62.4 |
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0.1 |
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0.1 |
Distance,
m |
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741 |
741 |
741 |
741 |
741 |
741 |
741 |
741 |
741 |
741 |
741 |
741 |
741 |
741 |
741 |
741 |
741 |
741 |
741 |
741 |
741 |
741 |
741 |
741 |
741 |
741 |
741 |
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0.1 |
Distance correction |
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-65 |
-65 |
-65 |
-65 |
-65 |
-65 |
-65 |
-65 |
-65 |
-65 |
-65 |
-65 |
-65 |
-65 |
-65 |
-65 |
-65 |
-65 |
-65 |
-65 |
-65 |
-65 |
-65 |
-65 |
-65 |
-65 |
-65 |
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0.2 |
Screening
correction(2) |
-10 |
-10 |
-10 |
-10 |
-10 |
-10 |
-10 |
-10 |
-10 |
-10 |
-10 |
-10 |
-10 |
-10 |
-10 |
-10 |
-10 |
-10 |
-10 |
-10 |
-10 |
-10 |
-10 |
-10 |
-10 |
-10 |
-10 |
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0.3 |
Atmospheric
Absorption(3) |
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0.0 |
0.0 |
-0.1 |
-0.1 |
-0.1 |
-0.2 |
-0.3 |
-0.5 |
-0.8 |
-1.2 |
-1.9 |
-2.7 |
-3.9 |
-5.3 |
-6.9 |
-8.5 |
-10.3 |
-12.1 |
-14.3 |
-17.1 |
-20.9 |
-26.6 |
-34.9 |
-46.9 |
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1.1 |
Predicted Lp, dB(A) |
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-9 |
-7 |
-3 |
3 |
3 |
5 |
9 |
9 |
12 |
15 |
15 |
16 |
16 |
16 |
17 |
15 |
13 |
11 |
10 |
6 |
2 |
-2 |
-6 |
-13 |
-25 |
-40 |
-60 |
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1.5 |
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2.6 |
Lp, dB(A) |
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0 |
0 |
0 |
3.5 |
2.9 |
5.1 |
9.4 |
9.4 |
11.7 |
15.5 |
14.6 |
16.3 |
15.9 |
16.1 |
16.6 |
14.5 |
12.8 |
11.1 |
9.7 |
5.8 |
2.0 |
0 |
0 |
0 |
0 |
0 |
0 |
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3.2 |
A-Wt
Sound Pr. Level = |
25.5 |
dB(A) |
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3.8 |
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4.5 |
FACADE CORRECTION= |
3 |
dB(A) |
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PREDICTED FACADE
NOISE LEVEL AT NSR = |
29 |
dB(A) |
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(1) Reference has been made on a test report of a wind turbine
with all measurements and analysis were done in accordance with the IEC 61400-11: Wind Turbine Generator Systems - Part 11:
Acoustic noise measurement techniques, and |
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with adjustment to represent the worst case
scenario of a maximum sound power level of 104dB(A). |
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(2) N1 will be totally screened off by the natural
topography. |
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(3) Basing on the equation Aab(fm) = Aat(fm) [1+0.00533[1-0.2303 Aat(fm)]]1.6 from Handbook of Acoustics (where Aab(fm) is the atmospheric attenuation for broadband at frequency fm, and Aat(fm) is the atmospheric
attenuation for |
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6.6 |
pure tone at frequency fm) and ISO 9613:Part 1
for Atmospheric Absorption at 30°C and relative humidity of 100% as the worse scenario (see Annex
A4.3). |
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0.0 |
Note: The average atmospheric condition in
Hong Kong was 23oC
and RH 79% as per the Weather Report 2005, "The Year's Weather -
2005" by Hong Kong Observatory. |
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1 |
1 |
1 |
2
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2
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3
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9
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9
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15
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35
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29
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43
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39
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41
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45
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28
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19
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13
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9
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4
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2
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1 |
1 |
1 |
1 |
1 |
1 |
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355
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25.5 |
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SWL(1), dB |
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65.2 |
67.5 |
70.9 |
77.6 |
77 |
79.3 |
83.6 |
83.6 |
86 |
89.9 |
89.2 |
91.2 |
91.2 |
92.1 |
93.4 |
92.5 |
92.2 |
92.1 |
92.3 |
90.2 |
88.2 |
86.4 |
85.5 |
82.2 |
75.2 |
68.5 |
61.1 |
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0.0 |
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102.74 |
dB(A) |
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1.3 |
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66.5 |
68.8 |
72.2 |
78.9 |
78.3 |
80.6 |
84.9 |
84.9 |
87.3 |
91.2 |
90.5 |
92.5 |
92.5 |
93.4 |
94.7 |
93.8 |
93.5 |
93.4 |
93.6 |
91.5 |
89.5 |
87.7 |
86.8 |
83.5 |
76.5 |
69.8 |
62.4 |
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104.04 |
dB(A) |
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