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China Harbour Engineering Company (Group) Noise Assessment Report for Grab Dredger (GD-853 40305V)
F:\Projects\MA3006\CNP\Grab v1.0 30530 CINOTECH i
TABLE OF CONTENTS
Page
1. INTRODUCTION .............................................................................................................1
2. ASSESSMENT METHODOLOGY..................................................................................1
3. NOISE MEASUREMENT RESULTS ..............................................................................3
4. CALCULATION ...............................................................................................................4
5 CONCLUSION..................................................................................................................4
List of Tables Table 2.1 Instrument list ....................................................................................................1 Table 3.1 Measurement Results for the Dredging Mode of Grab Dredger (GD-853
40305V) .............................................................................................................3 Table 3.1b Summary of the results ......................................................................................3 List of Figures Figure 1 Measurement Locations for Dredging Mode
China Harbour Engineering Company (Group) Noise Assessment Report for Grab Dredger (GD-853 40305V)
F:\Projects\MA3006\CNP\Grab v1.0 30530 CINOTECH 1
1. INTRODUCTION 1.1 Cinotech Consultants Limited was commissioned by the China Harbour Engineering
Company (Group) (hereinafter called “the Client”) to conduct a Sound Power Level (SWL) assessment for the Grab Dredger (GD-853 40305V) on 14 May 2003. The Client intended to evaluate the sound power level of the equipment for the application of construction noise permits. On-site noise measurements were conducted.
1.2 This report presents the noise assessment results and determines the sound power
level of the powered mechanical equipment (PME) mentioned above.
2. ASSESSMENT METHODOLOGY 2.1 The SWL measurement and calculation were follows to the procedures detailed in
ISO 3746-1995 (E), Acoustics – Determination of sound power levels of noise sources – Survey method.
2.2 A sound level meter with fast response mode was used for the measurement. The
meter was calibrated with a B&K 4231 acoustic calibrator before and after the measurements. The calibrations were checked to within ±1.0 dB(A).
2.3 A Laser Gun model no. (Criterion 300/400) was used to measure the distance between
the sound level meter and the noise source. 2.4 The instruments used for the measurement are summarised in Table 2.1 as below.
Table 2.1 Instrument List
Equipment Model Sound Level Meter B&K 2238 Sound Pressure Calibrator B&K 4231 Laser Gun Criterion 300/400
2.5 The measurement positions for dredging mode operation are shown in Figure 1. 2.6 The sound pressure level Leq (5 mins) of the PME in dredging mode was first
measured at the measuring points, and then the background noise level of Leq(5min.) was measured without the PME running. The measured noise levels were then averaged logarithmically to obtain the value of L'pA (for the PME in operating mode) and L''pA (for the background). The value was then corrected to account for the influence of background noise, by deducting a correction factor k. The noise emitted from the PME alone can then be found.
China Harbour Engineering Company (Group) Noise Assessment Report for Grab Dredger (GD-853 40305V)
F:\Projects\MA3006\CNP\Grab v1.0 30530 CINOTECH 2
2.7 The sound power level is then calculated with the use of the following formula:
LWA = LpfA + 10 log (S / S0) dB
where
LWA is the equipment sound power level, dB(A); LpfA is the A-weighted sound power level of the source, dB(A); S is the area of the measurement surface, in square metres; S0 reference distance (1 square metre)
k = - 10 log [ 1 - 10 -0.1 (L'pA - L''pA) ]
where
L'pA is the A-weighted sound pressure level averaged over the measurement
surface, in decibels, with the source under test in operation; L''pA is the A-weighted sound pressure level of background noise averaged
over the measurement surface, in decibels;
For the rectangular parallel-piped measurement surface,
S= 4 * (ab + bc + ca)
where a=(l1/2) + d, b= (l2/2) + d and c= l3 + d,
l1, l2, l3 are the dimensions of the rectangular reference parallelepiped; d is the measuring distance.
China Harbour Engineering Company (Group) Noise Assessment Report for Grab Dredger (GD-853 40305V)
F:\Projects\MA3006\CNP\Grab v1.0 30530 CINOTECH 3
3. NOISE MEASUREMENT RESULTS 3.1 The result of the measurement for dredging mode is given as below.
Table 3.1 Measurement Results for the Dredging Mode of Grab Dredger (GD-853 40305V)
Measurement Point Noise Level, dB(A)
A 68.3 B 64.0 C 73.9 D 71.6
Background avg. 58.5 Table 3.1b Summary of the results
Mode Dredging No. of pts 4
L'pA 70.8 dB(A) L''pA 58.5 dB(A)
l1 39.0 m l2 18.0 m l3 10.0 m d1 25 m d2 25 m d3 0 m
Area of measurement surface (m2) 9192
China Harbour Engineering Company (Group) Noise Assessment Report for Grab Dredger (GD-853 40305V)
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4. CALCULATION
Dredging Mode Difference in L'pA – L''pA : 70.8 – 58.5 = 12.3 dB(A)
Background noise correction factor : 0.00 dB(A) Area of measurement surface : 9192 m2
Sound power level:
LWA = LpfA + 10 log (S / S0) dB = (70.8 – 0.00) + 10 log (9192/1) = 110 dB(A)
5 CONCLUSION 5.1 The maximum sound power levels of the Grab Dredger GD-853 40305V is 110
dB(A).
FIGURE
China Harbour Engineering Company (Group) Noise Assessment Report for Grab Dredger (GD-1102 40357V)
F:\Projects\MA3006\CNP\Grab v1.0 30904 CINOTECH i
TABLE OF CONTENTS
Page
1. INTRODUCTION............................................................................................................1
2. ASSESSMENT METHODOLOGY...............................................................................1
3. NOISE MEASUREMENT RESULTS...........................................................................3
4. CALCULATION..............................................................................................................4
5 CONCLUSION ................................................................................................................4
List of Tables Table 2.1 Instrument List ....................................................................................................1 Table 3.1 Measurement Results for the Dredging Mode of Grab Dredger (GD-1102
40357V)..................................................................................................................3 Table 3.1b Summary of the results ........................................................................................3 List of Figures Figure 1 Measurement Locations for Dredging Mode Appendix A Field Measurement Record and Calculation of Sound Power Level
China Harbour Engineering Company (Group) Noise Assessment Report for Grab Dredger (GD-1102 40357V)
F:\Projects\MA3006\CNP\Grab v1.0 30904 CINOTECH 1
1. INTRODUCTION 1.1 Cinotech Consultants Limited was commissioned by the China Harbour Engineering
Company (Group) (hereinafter called “the Client”) to conduct a Sound Power Level (SWL) assessment for the Grab Dredger (GD-1102 40357V) on 4 September 2003. The Client intended to evaluate the sound power level of the equipment for the application of construction noise permits. On-site noise measurements were conducted.
1.2 This report presents the noise assessment results and determines the sound power
level of the powered mechanical equipment (PME) mentioned above.
2. ASSESSMENT METHODOLOGY 2.1 The SWL measurement and calculation were follows to the procedures detailed in
ISO 3746-1995 (E), Acoustics – Determination of sound power levels of noise sources – Survey method.
2.2 A sound level meter with fast response mode was used for the measurement. The
meter was calibrated with a B&K 4231 acoustic calibrator before and after the measurements. The calibrations were checked to within ±1.0 dB(A).
2.3 A Laser Gun model no. (Criterion 300/400) was used to measure the distance between
the sound level meter and the noise source. 2.4 The instruments used for the measurement are summarised in Table 2.1 as below.
Table 2.1 Instrument List
Equipment Model Sound Level Meter B&K 2238 Sound Pressure Calibrator B&K 4231 Laser Gun Criterion 300/400
2.5 The measurement positions for dredging mode operation are shown in Figure 1. 2.6 The sound pressure level Leq (5 mins) of the PME in dredging mode was first
measured at the measuring points, and then the background noise level of Leq(5min.) was measured without the PME running. The measured noise levels were then averaged logarithmically to obtain the value of L'pA (for the PME in operating mode) and L''pA (for the background). The value was then corrected to account for the influence of background noise, by deducting a correction factor k. The noise emitted from the PME alone can then be found.
China Harbour Engineering Company (Group) Noise Assessment Report for Grab Dredger (GD-1102 40357V)
F:\Projects\MA3006\CNP\Grab v1.0 30904 CINOTECH 2
2.7 The sound power level is then calculated with the use of the following formula:
LWA = LpfA + 10 log (S / S0) dB
where
LWA is the equipment sound power level, dB(A); LpfA is the A-weighted sound power level of the source, dB(A); S is the area of the measurement surface, in square metres; S0 reference distance (1 square metre)
k = - 10 log [ 1 - 10 -0.1 (L'pA - L''pA) ]
where
L'pA is the A-weighted sound pressure level averaged over the measurement
surface, in decibels, with the source under test in operation; L''pA is the A-weighted sound pressure level of background noise averaged
over the measurement surface, in decibels;
For the rectangular parallel-piped measurement surface,
S= 4 * (ab + bc + ca)
where a=(l1/2) + d, b= (l2/2) + d and c= l3 + d,
l1, l2, l3 are the dimensions of the rectangular reference parallelepiped; d is the measuring distance.
China Harbour Engineering Company (Group) Noise Assessment Report for Grab Dredger (GD-1102 40357V)
F:\Projects\MA3006\CNP\Grab v1.0 30904 CINOTECH 3
3. NOISE MEASUREMENT RESULTS 3.1 The result of the measurement for dredging mode is given as below.
Table 3.1 Measurement Results for the Dredging Mode of Grab Dredger (GD-1102 40357V)
Measurement Point Noise Level, dB(A)
A 69.4 B 63.6 C 73.2 D 71.4
Background avg. 53.9 Table 3.1b Summary of the results
Mode Dredging No. of pts 4
L'pA 70.6 L''pA 53.9
l1 38.0 l2 17.0 l3 10.0 d1 25 d2 25 d3 0
Area of measurement surface (m2) 8996
China Harbour Engineering Company (Group) Noise Assessment Report for Grab Dredger (GD-1102 40357V)
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4. CALCULATION
Dredging Mode Difference in L'pA – L''pA : 70.6 – 53.9 = 16.7 dB(A)
Background noise correction factor : 0.00 dB(A) Area of measurement surface : 8996 m2
Sound power level:
LWA = LpfA + 10 log (S / S0) dB = (70.6 – 0.00) + 10 log (8996/1) = 110 dB(A)
5 CONCLUSION 5.1 The maximum sound power levels of the Grab Dredger GD-1102 40357V is 110
dB(A).
FIGURE 1 MEASUREMENT LOCATIONS FOR DREDGING MODE
APPENDIX A FIELD MEASUREMENT RECORD & CALCULATION OF SOUND POWER LEVEL
Calculation Of Sound Power Level
Grab Dredger (GD-1102 4035 7V) Grabing Mode
Measurement Point Noise Level, dB(A) Background, dB(A)A 69.4 53.9B 63.6 53.9 d (a,b,c) SC 73.2 53.9 l1 38.0 25 44 8996D 71.4 53.9 l2 17.0 25 33.5Log average 70.6 53.9 l3 10.0 0 10
Difference in L'pA - L''pA 16.7Background noise correction factor 0.00Area of measurement surface 8996
LWA 110
China Harbour Engineering Company (Group) Noise Assessment Report for Tug Boat (HKD T-7 5873)
F:\Projects\MA3006\CNP\Tugboat v1.030602 CINOTECH i
TABLE OF CONTENTS
Page
1. INTRODUCTION....................................................................................................................... 1
2. ASSESSMENT METHODOLOGY ........................................................................................... 1
3. NOISE MEASUREMENT RESULTS........................................................................................ 3
4. CALCULATION......................................................................................................................... 4
5 CONCLUSION ........................................................................................................................... 4
List of Tables Table 2.4 - Instrument list ....................................................................................................................1 Table 3.1a - Measurement results ........................................................................................................3 Table 3.1b - Summary of the results ....................................................................................................3 List of Figures Figure 1 Measurement Locations for Sailing Mode
China Harbour Engineering Company (Group) Noise Assessment Report for Tug Boat (HKD T-7 5873)
F:\Projects\MA3006\CNP\Tugboat v1.030602 CINOTECH
1
1. INTRODUCTION 1.1 Cinotech Consultants Limited was commissioned by the China Harbour Engineering
Company (Group) (hereinafter called “the Client”) to conduct a Sound Power Level (SWL) assessment for the Tug Boat (HKD T-7 5873) on 14 May 2003. The Client intended to evaluate the sound power level of the equipment for the application of construction noise permits. On-site noise measurements were conducted.
1.2 This report presents the noise assessment results and determines the sound power
level of the powered mechanical equipment (PME) mentioned above.
2. ASSESSMENT METHODOLOGY 2.1 The SWL measurement and calculation were follows to the procedures detailed in
ISO 3746-1995 (E), Acoustics – Determination of sound power levels of noise sources – Survey method.
2.2 A sound level meter with fast response mode was used for the measurement. The
meter was calibrated with a B&K 4231 acoustic calibrator before and after the measurements. The calibrations were checked to within ±1.0 dB(A).
2.3 A Laser Gun model no. (Criterion 300/400) was used to measure the distance between
the sound level meter and the noise source. 2.4 The instruments used for the measurement are summarised in Table 2.1 as below.
Table 2.1 - Instrument List
Equipment Model Sound Level Meter B&K 2238 Sound Pressure Calibrator B&K 4231 Laser Gun Criterion 300/400
2.5 The measurement positions for sailing mode operation are shown in Fig. 1 2.6 The sound pressure level Leq (5 mins) of the PME in sailing mode was first measured
at the measuring points, and then the background noise level of Leq(5min.) is measured without the PME running. The measured noise levels were then averaged logarithmically to obtain the value of L'pA (for the PME in operating mode) and L''pA (for the background). The value was then corrected to account for the influence of background noise, by deducting a correction factor k. The noise emitted from the PME alone can then be found.
China Harbour Engineering Company (Group) Noise Assessment Report for Tug Boat (HKD T-7 5873)
F:\Projects\MA3006\CNP\Tugboat v1.030602 CINOTECH
2
2.7 The sound power level is then calculated with the use of the following formula:
LWA = LpfA + 10 log (S / S0) dB
where
LWA is the equipment sound power level, dB(A); LpfA is the A-weighted sound power level of the source, dB(A); S is the area of the measurement surface, in square metres; S0 reference distance (1 square metre)
k = - 10 log [ 1 - 10 -0.1 (L'pA - L''pA) ]
where
L'pA is the A-weighted sound pressure level averaged over the measurement
surface, in decibels, with the source under test in operation; L''pA is the A-weighted sound pressure level of background noise averaged
over the measurement surface, in decibels;
For the rectangular parallel-piped measurement surface,
S= 4 * (ab + bc + ca)
where a=(l1/2) + d, b= (l2/2) + d and c= l3 + d,
l1, l2, l3 are the dimensions of the rectangular reference parallelepiped; d is the measuring distance.
China Harbour Engineering Company (Group) Noise Assessment Report for Tug Boat (HKD T-7 5873)
F:\Projects\MA3006\CNP\Tugboat v1.030602 CINOTECH
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3. NOISE MEASUREMENT RESULTS 3.1 The result of the measurement for sailing mode is given as below.
Table 3.1a - Measurement results for the Sailing Mode of the Tug Boat
Measurement Point Noise Level, dB(A) Measurement Point Noise Level, dB(A) 1 78.4 11 75.4 2 80.9 12 75.0 3 79.1 13 76.0 4 78.1 14 76.5 5 77.2 15 75.9 6 76.9 16 75.0 7 76.7 17 76.3 8 75.6 18 77.0 9 74.8 19 77.9
10 74.5 20 78.0 Log average 77.1
Summary Table 3.1b - Summary of the Results
Mode Sailing No. of pts 20
L'pA 77.1 dB(A) L''pA 57.8 dB(A)
l1 12.2 m l2 4.7 m l3 2.0 m d1 1 m d2 1 m d3 0 m
Area of measurement surface (m2) 178.74
China Harbour Engineering Company (Group) Noise Assessment Report for Tug Boat (HKD T-7 5873)
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4. CALCULATION
Sailing Mode Difference in L'pA – L''pA : 77.1– 57.8 = 19.3 dB(A)
Background noise correction factor : 0.00 dB(A) Area of measurement surface : 178.74 m2
Sound power level:
LWA = LpfA + 10 log (S / S0) dB = (77.1 – 0.00) + 10 log (178.74/1) = 100 dB(A)
5 CONCLUSION 5.1 The maximum sound power levels of the Tug Boat (HKD T-7 5873) is 100 dB(A).
FIGURE
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