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ACOUSTIC
ENVIRONMENTAL NOISE
ENVIRONMENTAL IMPACT
PREPARED FOR:
GIGAWATT MOÇAMBIQUE S.A.
SGS Eko-Projekt sp. z o.o.
Cieszyńska 52a, 43-200 Pszczyna, Polska t +48 32 449 2500 f + 48 32 447 2072 e [email protected] www.sgs.com
Member of SGS Group (Société Générale de Surveillance)
SGS is the world’s leading inspection,
verification, testing and certification
company. Recognised as the global
benchmark for quality and integrity, We
provide innovative services and solutions
for every part of the environmental industry.
Our global network of offices and
laboratories, alongside our dedicated team,
allows us to respond to your needs, when
and where they occur.
ACOUSTIC
ENVIRONMENTAL NOISE ENVIRONMENTAL IMPACT
16/04/2014
Prepared by Prepared for
SGS EKO-PROJEKT Gigawatt Moçambique S.A.
Gigawatt Mocambique S.A.
Maputo
Order: 14004861
This report is approved by
Dawid Byrdy Acoustic Department Manager ----------------------------------------------------------- Name Surname 1 Title 1
N/A
----------------------------------------------------------- Name Surname 2 Title 2
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INDEX
REPORT CONTENT
1. EXECUTIVE SUMMARY ............................................................................................................... 2
2. SCOPE OF WORK ........................................................................................................................ 3
3. METODOLOGY ............................................................................................................................ 4
4. CONFIGURATION OF CALCULATION/ FACTORS AFFECTING THE NOISE PROPAGATION 5
5. REFERENCE POINTS .................................................................................................................. 6
5.1 CALIBRATION POINTS .................................................................................................................... 6
5.2 RESIDENTAL REFERENCE POINTS .................................................................................................. 7
6. NOISE LIMITS – RESIDENTAL ZONES ....................................................................................... 8
7. ACOUSTIC INPUT DATA ............................................................................................................. 8
8. RESULTS OF CALCULATION ................................................................................................... 10
8.1 AGGREKO I – ACOUSTIC MAP 2D/3D............................................................................................. 10
8.2 GIGAWATT /PLUS/ CTRG- ACOUSTIC MAP 2D/3D ......................................................................... 11
8.3 AGGREKO I /PLUS/ GIGAWATT - ACOUSTIC MAP 2D/3D ................................................................. 12
8.4 AGGREKO I /PLUS/ GIGAWATT /PLUS/ CTRG - ACOUSTIC MAP 2D/3D ............................................. 13
8.5 RESULTS OF CALCULATIONS ....................................................................................................... 14
9. UNCERTAINTY OF AN ANALYSIS ............................................................................................ 15
10. SUMMARY .................................................................................................................................. 15
11. APPENDICES TO REPORT 101/PL/2014 .................................................................................. 15
LIST OF APPENDICES
Appendix 1: SGS report prepared for Gigawatt Mocambique S.A. - 01/ENVI/SGS/2014
16 February 2014.
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1. EXECUTIVE SUMMARY
SGS was contracted to perform environmental impact assessment connected with noise from planned
plant of Gigawatt in accordance with ISO standard basis on noise measurements made for existing
Plant. Investment is localized in Mozambique /S 25°27'45.7" E 32°00'07.0"/.
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2. SCOPE OF WORK
.
The scope of work:
Prepare GIS input data (geometric model)
Analysis of made noise measurements
Preparing acoustic model
Acoustic model calibration
Calculations
Preparing acoustics maps
Comparing results of calculation with noise limits on residential zones
Summary
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3. METODOLOGY
Measurements:
Based on Environmental Noise Survey made by SGS - 16 February 2014
Calculations:
According to ISO 9613-2 Acoustics - Attenuation of sound during propagation outdoors
Part 2: General method of calculation.
The basic factor which characterized noise source is sound power level. Noise coming from
individual sources is represented by the set of equivalent point sources of a certain acoustic power
level A.
The equivalent sound level A that occurs at any point in space, is the sum of the sounds coming
from all point and apparent sources, and its value is calculated from the formula:
ALL Weq
where:
LW - sound power level A of the point source expressed in dB (A)
A - damping occurring on the route of the source - a point of observation.
The total damping A is the result of the imposition of consecutive physical phenomena occurring in the
way of propagation and could be marked in a general way:
innebargratmdiv AAAAAA
where:
Adiv – attenuation due to the geometric divergence,
Aatm - damping due to the atmospheric absorption,
Agr - damping introduced by the surface area;
Abar - damping which results from the diffraction on obstacles on the route of acoustic wave
propagation (shielding).
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4. CONFIGURATION OF CALCULATION/ FACTORS AFFECTING THE NOISE PROPAGATION
Configuration of calculation:
Software CadnaA 4.2/ IMMI 2011 Premium
GRID 10 x 10 [m]
Reflections number 1
G parameter 0 – no absorption / 1,0 absorption
Results height 4 [m]
Module ISO 9613
Factors affecting the noise propagation are mostly connected with:
Ground absorption (G=1)
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Digital Terrain Model (various terrain model)
5. REFERENCE POINTS
.
5.1 CALIBRATION POINTS
To calibrate acoustic model SGS used results from measurements described in Report from 16
February 2014. For calibration the model SGS used only the nearest points and results without
distortion.
Localization of calibration points and acoustic data based on SGS report: Environmental Noise Survey
– 16 February 2014.
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No Name Coordinates Z [m]
1 Giga 1 S 25°27'45.7" E 32°00'07.0" ~1,5
2 Giga 2 S 25°27'43.7" E 32°00'13.3" ~1,5
3 Giga 3 S 25°27'41.8" E 32°00'24.9" ~1,5
4 Aggreko 1 S 25°27'50.0" E 32°00'34.3" ~1,5
5 Aggreko 2 S 25°27'55.9" E 32°00'27.9" ~1,5
5.2 RESIDENTAL REFERENCE POINTS
Residential reference points describes acoustic climate on residential zones. Results in these points
are used to compare results from calculation with noise limits. Because of long distance reference
points from noise sources these points wasn’t used to calibrate model (except point “Giga 1”).
Localization of reference points based on SGS report: Environmental Noise Survey – 16 February
2014.
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No Name Coordinates Z [m]
1 Giga 1 S 25°27'45.7" E 32°00'07.0" ~1,5
2 Giga 4 S 25°28'16.3" E 31°59'49.4" ~1,5
3 Giga 7 S 25°27'13.8" E 31°59'55.9" ~1,5
6. NOISE LIMITS – RESIDENTAL ZONES
Currently there are no Mozambican standards for environmental noise and the noise levels calculated
in this acoustic analysis were compared against the World Health Organization (WHO) Guidelines also
set by the International Finance Corporation (IFC), “Noise Level Guidelines”.
According to these Guidelines, noise impacts should not exceed the levels presented in below Table.
Note that the guideline values for noise levels measured out of doors adopted by the IFC are actually
those defined by the World Health Organization (WHO) – Guidelines for Community Noise (1999).
No Name Noise limits LAeq [dB]
Day-time (07:00 - 22:00) Night-time (22:00 -07:00)
1 Giga 1 55 45
2 Giga 4 55 45
3 Giga 7 55 45
7. ACOUSTIC INPUT DATA
For existing plants acoustic data is connected with SGS report: Environmental Noise Survey – 16
February 2014 (data used in calibration process).
For Gigawatt acoustic data delivered by Contractor.
Air borne noise levels are guaranteed to be 70dB(A) ± 2dB at 1m. Measures are corrected following
ISO 3741-75 (UNE 74-031-87).
Noise level in Control Room not exceed A weighted surface sound pressure level (SPL) of 57 dB(A).
The reference acoustic pressure for sound pressure level is 20 μPa
The A-weighted surface sound pressure level is averaged over the measurement surface according to
ISO 3746 1995 and measured at a distance of 1 meter from the equipment or its acoustical enclosure
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and 1.5 meter above ground level or personnel platforms, which needs to be accessed during normal
operation.
The A-weighted surface sound pressure level is measured and averaged on several points in the room
when printer and alarms are not working (applicable only for sound pressure level guarantee in control
room)
Building standards (as per the Employers Requirements):
South African National Standards (SANS) SANS 717-1 & 2 Acoustics -- Sound insulation in buildings
and of building elements
SANS 1381 Materials for thermal insulation of buildings
For CTRG acoustic data delivered by Contractor.
Based on Noise Impact Study Ressano Garcia 12xW20V34SG -24.10.2014.
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8. RESULTS OF CALCULATION
8.1 AGGREKO I – ACOUSTIC MAP 2D/3D
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8.2 GIGAWATT /PLUS/ CTRG- ACOUSTIC MAP 2D/3D
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8.3 AGGREKO I /PLUS/ GIGAWATT - ACOUSTIC MAP 2D/3D
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8.4 AGGREKO I /PLUS/ GIGAWATT /PLUS/ CTRG - ACOUSTIC MAP 2D/3D
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8.5 RESULTS OF CALCULATIONS
Aggreko I:
No Name Coordinates Z [m] LAeq [dB] UR,95 [dB]
1 Giga 1 S 25°27'45.7" E 32°00'07.0" ~1,5 51,5 3,8
2 Giga 4 S 25°28'16.3" E 31°59'49.4" ~1,5 39,7 3,8
3 Giga 7 S 25°27'13.8" E 31°59'55.9" ~1,5 41,1 3,8
Gigawatt /plus/ CTRG:
No Name Coordinates Z [m] LAeq [dB] UR,95 [dB]
1 Giga 1 S 25°27'45.7" E 32°00'07.0" ~1,5 38,9 3,8
2 Giga 4 S 25°28'16.3" E 31°59'49.4" ~1,5 29,3 3,8
3 Giga 7 S 25°27'13.8" E 31°59'55.9" ~1,5 26,4 3,8
Aggreko I /plus/ Gigawatt:
No Name Coordinates Z [m] LAeq [dB] UR,95 [dB]
1 Giga 1 S 25°27'45.7" E 32°00'07.0" ~1,5 51,7 3,8
2 Giga 4 S 25°28'16.3" E 31°59'49.4" ~1,5 39,8 3,8
3 Giga 7 S 25°27'13.8" E 31°59'55.9" ~1,5 41,2 3,8
Aggreko I /plus/ Gigawatt /plus/ CTRG:
No Name Coordinates Z [m] LAeq [dB] UR,95 [dB]
1 Giga 1 S 25°27'45.7" E 32°00'07.0" ~1,5 51,7 3,8
2 Giga 4 S 25°28'16.3" E 31°59'49.4" ~1,5 39,9 3,8
3 Giga 7 S 25°27'13.8" E 31°59'55.9" ~1,5 41,2 3,8
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Influence of Gigawatt in reference points:
No Name Coordinates Influence %
1 Giga 1 S 25°27'45.7" E 32°00'07.0" 3,63
2 Giga 4 S 25°28'16.3" E 31°59'49.4" 2,37
3 Giga 7 S 25°27'13.8" E 31°59'55.9" 1,94
9. UNCERTAINTY OF AN ANALYSIS
Uncertainty of an analysis:
2
95,0,
2
95,0,95,0,/ BANLAeqD UUU
UA,95 = 3,0 dB
UB,95 = 2,3 dB
8,395,0,/ NLAeqDU
Uncertainty of calculation method = 3,0 dB
Uncertainty of calculation method/measurements/geometry/Assumption = 3,8 dB
10. SUMMARY
Results of calculation shows that influence of Gigawatt on residential zones will be inoffensive. Impact
of Gigawatt in reference points will be less than 4 % and Gigawatt will not exceed limit values in
residential zones. Acoustic climate is mostly created by Aggreko I. To improve acoustic situation on
residential zones it will be necessary to reduce impact of Aggreko noise sources.
Recommendations from point 8 of SGS report (16 February 2014) are still valid.
11. APPENDICES TO REPORT 101/PL/2014
Appendix 1: SGS report prepared for Gigawatt Mocambique S.A. - 01/ENVI/SGS/2014
16 February 2014.