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NOISE MODELLING STUDYTAWEELAH B EXTENSION PROJECT

December 2004



Report Title : Noise Modelling Study - Taweelah B ExtensionProject

Report Status : Draft Issue

Job No : 61864B

Date : December 2004

Prepared by : ............................................................................Humphrey Roberts-Powell

Checked by : ............................................................................Richard Perkins

Check Cat : A

Approved by : ............................................................................Ross Singleton



CONTENTS

Page

1 INTRODUCTION 5

1.1 General 5

1.2 Scope of Study 5

2 ASSESSMENT CRITERIA 5

2.1

World Bank 5

2.2 Project Specification 5

2.3 Environmental Research Wildlife and Development Agency (ERWDA) 6

2.4 World Health Organisation 6

3 METHODOLOGY 6

3.1 Supplied Data 6

3.2 Noise Model 7

4 EXISTING NOISE CLIMATE 9

4.1 Noise Plot 9

4.2 Existing Level of Compliance 9

5 PREDICTED NOISE LEVELS FROM NEW B EXTENSION 9

5.1 Noise Plot 9

6

PREDICTED CUMULATIVE NOISE LEVELS 9

6.1 Noise Plot 9

6.2 Predicted Level of Compliance 9

7 SUMMARY OF RESULTS 10

8 CONCLUSION 10

REFERENCES: 11

FIGURES 2-5 12

Noise Plots 12



Taweelah B Extension ProjectNoise Modelling Study

EXECUTIVE SUMMARY

Parsons Brinckerhoff Ltd (PB) was commissioned by Marubeni Corporation to undertake a noisemodelling study of the Al-Taweelah power and desalination plants near Abu Dhabi, UAE. Supplieddata has been reviewed, a noise model of the existing plant has been created, and the noise impactof the new plant items on the surrounding area has been predicted using a computer based 3-Dmodel.

It is predicted that, provided the noise provisions in the project specifications are complied with, noiselevels will not exceed 58 dB(A) at the northern site boundary nor 51 dB(A) at the eastern siteboundary after the New B Extension is built. Noise levels are therefore predicted to comply with all

applicable legislative requirements.

If new equipment exceeds the ‘85 dB(A) at 1 metre’ project limit for open air installations by up to 3dB, it is predicted that noise levels at the northern site boundary will remain under 60 dB(A), and willtherefore still comply with all criteria there.




1 INTRODUCTION

1.1 General

1.1.1 Parsons Brinckerhoff Ltd (PB) was commissioned by Marubeni Corporation toundertake a noise modelling study of the Al-Taweelah power and desalination plantsnear Abu Dhabi, UAE. The study will form part of an Environmental AssessmentImpact of the site, commissioned as part of a proposal to develop the power anddesalination facilities of the Existing B plant, with a new extension adjacent to the

existing site.

1.2 Scope of Study

1.2.1 The site will be required to comply with various noise limits, which are discussedbelow. This assessment aims to model existing noise sources and to predictboundary noise levels before and after the proposed extension to verify compliancewith the limits, and to provide the operator with a noise contour map of the site andadjoining land area.

2 ASSESSMENT CRITERIA

2.1 World Bank

2.1.1 In the ‘Pollution Prevention and Abatement Handbook’ issued by the World BankGroup in July 1998 (Reference 1), noise limits for new installations financed by theWorld Bank are set out, which are summarized below in Table 1. Additionally, it is

stated in the handbook that an increase of up to 3 dB above the existing backgroundlevels outside the project property boundary is considered acceptable.

Maximum L Aeq, dBReceptor

Day (07:00 - 22:00) Night (23:00 - 07:00)

Residential, institutional, educational 55 45

Industrial, commercial 70 70

Table 1: World Bank noise limits

2.2 Project Specification

2.2.1 Noise limits are also set out by ADWEA (Abu Dhabi Water and Electricity Authority) intheir General Technical Specifications for the Al-Taweelah Plant B project (Reference2), which are presented in Table 2, below. In the document, it is also stated that, “To




2.3 Environmental Research Wildli fe and Development Agency (ERWDA)

2.3.1 The following table summarizes the relevant environmental noise regulatory limitsestablished by UAE Federal Environmental Law.

Maximum Noise L Aeq,1hr dB Area

Day (07:00 –20:00) Night (20:00-07:00)

Residential Area with Light Traffic 40 - 50 30 - 40

Residential Areas in the Downtown 45 - 55 35 - 45

Residential Areas which include someworkshops and commercial businessor residential areas near highway

50 - 60 40 - 50

Commercial Areas and Downtown 55 - 65 45 - 55

Industrial Areas (Heavy Industry) 60 - 70 50 - 60

Table 3: ERWDA noise limits

2.4 World Health Organisation

2.4.1 In the WHO document ‘Guidelines for Community Noise’ (Reference 3), guideline limitvalues for community noise in various specific environments are provided. Noiselevels below the limits are considered necessary to minimize any temporary or long-term deterioration in physical, psychological or social functioning associated withnoise exposure. The values form the basis of many international environmental noisepolicy limits and are summarized in Table 4, below.

Specific Environment Critical Health Effects Maximum L Aeq, dB

Outdoor living Area (daytime + evening) Moderate Annoyance 60Inside bedrooms Sleep disturbance 30

Outside bedrooms, window open Sleep disturbance 45

Industrial, commercial Hearing impairment 70

Table 4: WHO noise limits

2.5 Summary

2.5.1 Compliance with the project specification, detailed in Section 2.2.1, will ensurecompliance with all other criteria, provided neighbouring receptor locations areclassified as industrial.

3 METHODOLOGY




3.2 Noise Model

3.2.1 CadnaA, the computer-based noise propagation modelling package used for themodel, incorporates the calculation procedure set out in ISO 9613 Parts 1 & 2(References 5 & 6), and can provide an accurate visual representation of noise levels.

3.2.2 A three-dimensional model of the existing Taweelah A1, A2, Initial B, and Initial BExtension sites was constructed, based around a CAD file of the site plan. Thedimensions of all significant on-site buildings and barriers were incorporated into themodel.

3.2.3 The significant noise sources for all the existing plants were then identified, and builtin the model at their correct locations. Figure 1, below, shows the constructed 3-Dmodel of the existing site viewed from the north. Significant noise sources are shownin blue.

Figure 1: 3D Model of site viewed from the north




within 2 dB at the site boundary, as levels here are verified by the results of the

background study. Noise levels near the sources will be less accurate becausesource sound power levels have not been verified.

3.2.8 To construct the model to show predicted noise levels after the addition of theproposed New B Extension, noise data relating to all the new noise sources wasreviewed. The levels and spectra of the noise sources were obtained from themanufacturers, where available. Noise levels from the PB database were used wherenone for the specific equipment was made available. These were taken from similarequipment with similar power ratings

3.2.9 The noise sources and associated octave band sound power levels used in the modelfor New B Extension plant items are listed overleaf in Table 5.

3.2.10 It is assumed in the model that all plant will comply with the project specification(Reference 2), which states that all open air installations should achieve a soundpressure level of 85 dB(A) at a distance of 1m.

3.2.11 Noise data provided by manufacturers of the plant items relate to their maximum

output capacity. Realistically, their noise outputs will be lower during the night,however, this difference in level is hard to predict. Consequently, it is assumed thatthe equipment will run constantly at full power, representing a ‘worst-case’ scenario atnight.

3.2.12 All noise sources have been modelled as uniformly radiating ‘point’ sources, with theexception of the gas and steam turbine hall walls and roof, which have been modelledas ‘area’ sources, and the desalination units, which have been modelled as ‘line’sources. It has been assumed that there are no unsilenced noise transmission paths

from inside the turbine halls to the outside environment, and that any roller shutterdoors in their facades are closed.

Octave Band Sound Power Levels re 10-12

WNoise Source

31.5 63 125 250 500 1000 2000 4000 8000

Total SoundPower dB(A)

GT Hall Enclosure Walls 123 124 120 117 115 113 116 111 105 121

ST Hall Enclosure Wall 118 118 115 113 116 113 110 107 106 118

GT Hall Enclosure Roof 119 120 116 113 111 109 112 107 101 117

ST Hall Enclosure Roof 114 114 111 109 112 109 106 103 102 114

GT Air Handling Units (each) 119 116 111 96 92 83 85 84 83 98

ST Air Handling Units (each) 117 114 109 94 90 81 83 82 81 96

GT Hall Roof Hoods 95 109 99 96 87 90 91 95 94 100

ST Hall Roof Hoods 95 105 100 98 96 90 91 91 86 99




4 EXISTING NOISE CLIMATE

4.1 Noise Plot

4.1.1 The noise plot presented in Figure 2 shows a representation of existing site noiselevels. See section 3.2.7 for a comment on the accuracy of levels near the noisesources.

4.2 Exist ing Level of Compliance

4.2.1 The maximum existing noise levels at the site complex boundary that are likely to beattributable to Plant B noise sources are around 55 dB(A) on the northern boundary,towards the shore line. At the eastern plant boundary, the highest noise levels arearound 43 dB(A).

4.2.2 The existing levels comply with the project limits, assuming that the levels measuredby Dome were representative of normal operating conditions.

5 PREDICTED NOISE LEVELS FROM NEW B EXTENSION

5.1 Noise Plot

5.1.1 The noise plot presented at the end of this report in Figure 3 shows the predictednoise levels associated only with the proposed New B Extension.

5.1.2 The maximum existing noise levels at the site complex boundary from New Plant BExtension noise sources are around 57 dB(A) at the northern boundary. At the

eastern plant boundary, the highest noise levels are around 51 dB(A).

6 PREDICTED CUMULATIVE NOISE LEVELS

6.1 Noise Plot

6.1.1 A noise plot showing predicted cumulative noise levels from the entire plant after theproposed New B Extension in plan view is presented in Figure 4.

6.1.2 A comparison of the existing and predicted noise levels, showing the rise in noiselevels associated with the new plant, is presented in Figure 5.

6.2 Predicted Level of Compliance

6 2 1 Th i di d b d i l l f h d i




7 SUMMARY OF RESULTS

The table below presents a summary of the results from the different scenarios. Foreach scenario, the maximum level at each boundary is shown.

Existing Proposed Cumulative

Figure 2 Figure 3 Figure 4Boundary

A1, A2, IB, IBE NBE A1, A2, IB, IBE, NBE

Northern 55 dB(A) 57 dB(A) 58 dB(A)

Eastern 43 dB(A) 51 dB(A) 51 dB(A)

Southern 47 dB(A) 45 dB(A) 48 dB(A)

Table 5: Maximum levels at each boundary from each scenario.

8 CONCLUSION

8.1.1 Parsons Brinckerhoff Ltd (PB) was commissioned to undertake a noise modelling

study of the Al-Taweelah power and desalination plant near Abu Dhabi, UAE.Supplied data has been reviewed, a noise model of the existing plant has beencreated, and the noise impact of the new plant items on the surrounding area hasbeen predicted using a computer based 3-D model.

8.1.2 It is predicted that, provided the noise provisions in the project specifications arecomplied with, noise levels will not exceed 58 dB(A) at the northern site boundary nor51 dB(A) at the eastern site boundary. Noise levels are therefore predicted to complywith all applicable legislative requirements.

8.1.3 If new equipment exceeds the ‘85 dB(A) at 1 metre’ project limit for open airinstallations by up to 3 dB, it is predicted that noise levels at the northern siteboundary will remain under 60 dB(A), and will therefore still comply with all criteriathere.




REFERENCES:

1. ‘Pollution Prevention and Abatement Handbook’, World Bank Group, July 1998

2. ADWEA Taweelah B Project. Part II.A of RFP. General Technical Specifications

3. ‘Guidelines for Community Noise’, World Health Organisation, 1999

4. ‘Taweelah B Extension Project Environmental Noise Survey Report’, Dome OilfieldEquipment & Services. Ref: ED42-04 November 2004.

5. ISO 9613-1:1996 Attenuation of sound during propagation outdoors - Part 1: Calculation ofthe absorption of sound by the atmosphere.

6. ISO 9613-2:1996 Attenuation of sound during propagation outdoors - Part 2: General methodof calculation.




FIGURES 2-5

NOISE PLOTS

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