environmental noise modeling-final report-updated.pdf

Environmental Noise Modeling Using Soundplan 7.2 Software

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Chapter-1

INTRODUCTION

The worldwide development in urbanization presents a common factor, i.e., the

worsening of environmental pollution through gas emissions, water pollution and noise

pollution.

Amongst all of these types of pollution’s, environmental noise is a worldwide

problem. However, the way the problem is dealt with differs vastly from country to

country and is very much dependent on culture, economy and politics. But the problem

continues even in areas where extensive resources have been used for regulating,

assessing and damping noise sources or for creation of noise barriers. For example, the

noise that spreads urban populations is produced by various sources, whose nature may

be simple or complex, comprising noise generated by industries (e.g., from the metal

mechanical and construction sectors), transportation systems (roads, railroads, aircraft),

by neighbours, and by a wide variety of leisure activities such as cultural and sports

events, etc. Many sectors of society are affected by noise pollution. In response to urban

and industrial noise pollution, many studies have focused on environments intended for

activities that involve a high degree of cognitive and intellectual activity, such as

educational and working environments.

In recent years, noise and urban planning have been studied extensively based on

noise mapping.

Management of the risks associated with using noise mapping predictions requires

clear communication of the relevant issues between practitioners and the end users of the

information. Therefore it is necessary for all parties involved to have some appreciation

of what is involved when producing environmental noise models and the range of

approaches that can be adopted. In particular, what it is that a noise model will represent,

for which types of applications do models offer useful information, and what are the

relative benefits and limitations of modelling compared to other types of objective

assessment?


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In the preceding sections, environmental noise modelling overview has been

discussed to address these types of questions, and thus provide a basis on which non-

technical parties can engage with practitioners.

1.1 Why Environmental Noise Modelling

This thesis has been prepared for all parties who commission, undertake or use

environmental noise predictions for commercial or industrial operations, of whatever type

or scale, for which an environmental noise assessment may be required.

The guidance is directly pertinent to predictive studies carried out in support of

the following types of assessment:

Pollution Prevention and Control (PPC) permitting

BS 4142 and BS 9142 based investigations

ADNOC Code of Practice on Environmental Impact Assessment Planning

condition compliance

Development of site specific noise mitigation methodologies

The guide is intended to:

Raise awareness of the usefulness of environmental noise prediction studies

Raise awareness of the intrinsic inconsistency of environmental noise fields, and

the subsequent risk of incorrect assessment outcome that may result when

attempting to utilise any objective rating method

Provide an understanding of the types of possibly significant risks involved in

using environmental noise predictions to inform decision making processes

Promote the management of such risks from the outset of an investigation by

adopting a organized approach to the design of prediction studies that recognises

the relationship between variability, uncertainty and risk

Raise awareness of the inevitable practical, technical, and commercial limitations

that succeed in all methods of noise assessment, and of the conclusion that limited

assessment resources are best focused on decrease of risk rather than of

uncertainty


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Assist users to balance the risks arising from a restricted predictive study against

other constraints and considerations, and thus identify instances where alternative

assessment methods may need to be considered

1.2 Environmental Noise Modelling

Environmental noise modelling describes the procedure of theoretically

estimating noise levels within a region of interest under a precise set of conditions.

The precise set of conditions for which the noise is being estimated will be a fixed

representation or 'snapshot' of a physical environment of interest. However, in practice

the physical environment around us will usually not be fixed, but will be characterized by

continually varying conditions. These variations in real world conditions will then cause

the actual sound field to differ in time and space. Thus it is important to identify that the

output of an environmental noise model(s) will only signify an estimate for a ‘snapshot’

of the range of actual environmental noise levels that could occur in time and space.

Knowing that noise modelling is a means of estimating noise for a specific set of

conditions, then the questions arises what these conditions are. The key conditions that a

noise model relates to are:

An estimation of the noise source, or sources, for which associated environmental

noise levels are of interest

An approximation of the physical environment through which noise will spread in

to surrounding from the noise source(s) to the location or area of interest. This

includes the ground terrain, the built environment, and weather conditions (e.g.

wind, temperature, humidity)

An approximation of the way in which sound will travel from the input noise

source(s) via the input physical environment, to the receiver location or area of

interest.

Thus, creating an environmental noise model involves defining a series of noise

sources to be scrutinized, describing acoustically important features of the

environment through which sound will propagate to the receiver, and then

applying a calculation method that accounts for these descriptions to produce an


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predictable noise level at a location or area of interest. To demonstrate this

concept, following Figure 1 below represents a schematic diagram of the simplest

type of environmental noise model, involving a single sound source, radiating

sound via a single transmission path, to a single location in the surrounding space:

Figure 1: The simplest type of model

In practice, environmental noise models will often be more complex which

involves multiple sound source(s), transmitting via multiple complex transmission paths,

to multiple locations of interest.

In these more difficult scenarios, the noise model is repetitively calculated for

each of the sound source, via each transmission path to each and every receiver location.

The aggregate sound level at each location is then calculated by summing the

contribution of each source and transmission path.

Application of noise prediction calculations to each point on a uniformly

distributed grid allows a noise contour map to be developed to illustrate regions of equal

predictable noise level and depict trends in the spatial pattern of the sound field:

Figure 2: Noise Contours


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1.3 Uses of the Environmental Noise Modelling:

Now day’s environmental noise modelling predictions are mostly used in

decision-making applications. Common application of noise prediction is for assessments

where a decision has to be made regarding some upcoming change to an environmental

noise field. However, considering the practical scenarios and technical challenges in

noise measurement strategies, there are certain situations in which predictions

complement or substitute for measurement-based noise assessment techniques.

Following are the common uses of noise predictions for practical noise assessment

purposes:

Forecasting the effects or benefits of proposed changes to an environmental noise

field such as introduction, any modification or removal of a commercial/industrial

installation, or modification of substantial features in the physical environment

that affect noise propagation, such as the construction or removal of barriers or

enclosures.

Effectiveness of different noise mitigation strategies needs to be evaluated by

assessment of existing commercial/industrial installations. Noise assessment helps

in predicting noise levels which can be used to rank the relative contributions of

individual component sources of an installation comprising multiple complex

sources. These rankings predicted by noise models can then be used to focus noise

mitigation resources on to the component sources whose treatment will enable the

greatest reduction in total noise levels.

Scrutinizing the results of a noise measurement study helps us to better understand

the reasons of the measured noise levels. For example, predictions may be used to

assist the investigation of observed, but unexplained inconsistency in the noise

measurement results. Alternatively, predictions can be used to provide an estimate

of the extent to which a particular source (s), may have influenced the total noise

level measured from all sources affecting the environment in question.

Supplementing the results of measurement studies to scrutinize a wider range of

locations, time periods or noise sources than can be directly investigated with

measurements.


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Supporting the design of measurement studies by using noise predictions to

understand the possible criticality of the situation before obligating to expensive

measurement studies. The noise predictions results can be used to identify

situations that are most serious to the assessment outcome, such as locations

where noise levels might be anticipated to be similar to some threshold value

where the assessment outcome considerably differs.

This knowledge can then be used to design the measurement study in a way that

focuses the available resources on the most effective strategy. A further benefit of

noise model predictions used in this way is the reference it provides when

conducting post measurement analysis to judge the validity of a set of

measurements, and whether there are any aspects of the results that differ from

original expectations and then permit specific explanation or further analysis.

1.4 Information Needed to Construct a Noise Model

There are many approaches to environmental noise modelling which varies in

terms of the complexity with which each element of the model is described and analysed.

However, regardless of the chosen approach in noise modelling, the important

information to all noise prediction studies is the systematic representation of the noise

sources to be investigated and the physical environment (surroundings) through which

noise will transmit to the receivers. Once these are important information defined

properly, an estimate in which noise will travel from the noise sources to the receivers is

also required. Following Table 1 shows the necessities for specifying a noisy

environment:


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Table 1: Necessities of the specification of a noisy environment

Stage Minimum requirements Other information that may be

required

The noise

source (s)

investigation

Number of sound source (s)

Total sound power output of

each noise source.

Directional characteristics of

each noise source.

Height of each noise source

Frequency characteristics of

each noise source

Time variations of emissions

Information to determine which value

or range of values best associates to

the conditions for which the noise

assessment can be applicable. For

example, a worst-case assessment

would suggest the use of the highest

possible value regardless of how often

it may occur during the noise

assessment which related to 'typical'

conditions could require the use of an

averaged value or some typically

recurring upper value.

The physical

environment

through which

noise will

transmit to the

receivers.

Separation distances between all

pertinent noise sources and

receivers.

Release directions of the noise

sources

Reflecting/obstructing structures

Height(s) of receiver(s)

Ground terrain profile

Characteristics of the ground cover

Meteorological conditions relevant to

the intentions of the assessment (e.g.

worst case such as downwind

propagation, or generally recurring

long term conditions). These may

include wind direction and speed,

variations with wind and temperature

with height above ground,

temperature, and humidity

To estimate the manner in which noise will travel from the noise sources to the

receivers in the given surrounding, a different range of sound propagation methodologies


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can be employed. Sound propagation methods vary extensively in their complexity and

the scope of applications for which they can offer significant predictions.

The most basic form of noise propagation methodology is described as 'spherical'

or 'hemispherical' spreading. This noise propagation method simply accounts for the

discount in sound intensity as a sound wave front propagates over a larger area.

For common types of noise sources in relatively simple environments, where

separating distances are relatively lesser and there are no superseding structures to

obstruct noise propagation, this type of method is often sufficient for estimation purposes.

In instances where the noise sources are more multifaceted and/or account must

be made of the effect of significant features of the physical environment, more robust and

thorough information is needed to describe the propagation of noise in the surroundings.

In most types of practical applications, engineering methods used to provide the most

feasible basis for predicting environmental noise levels. These methods rely on a

combination of acoustic principles and empirical knowledge to provide a means of

estimating the influence of a range of phenomena, including:

The absorption associated with the passage of noise through the surroundings

The change in noise level that occurs as a result of interactions between the sound

wave travelling directly to the receiver and those reflected from the ground,

accounting for influence of the ground cover type

The weakening of the noise level offered by barriers that fully or partly obstruct

line of sight between a source and a receiver location

The influence of atmospheric conditions that can change the direction of an

advancing sound wave front by refracting the wave at points where there are

significant changes in wind speed and/or temperature

The influence of reflecting surfaces that re-direct an advancing sound wave front

Engineering methods to determine noise levels can therefore take account of a

wide range of features that influence noise transmission, and their use for multi-source

industrial/commercial applications can become difficult when all pertinent paths of sound

transmission are taken into consideration. Whilst these noise prediction methods provide

a robust way of describing sound transmission in many general applications, it must be


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recognised that there will be more difficult situations where their explanation does not

properly account for what will actually happen in reality. Example situations include

assessments linking to noise sources with very distinct frequency characteristics and, in

particular, situations where the influence of different aspects of the physical environment

cannot be considered in isolation.

Hence it is important that noise modelling methods are used with proper regard to their

limitations. It means that their explanations are only relied upon for very comprehensive

value estimates of the noise where practicable to do so (e.g. in several instances where

you might have seen about large margin between the predicted value and the decision

threshold). Instead, it can be a case of modifying the predicted values where the

limitations can be quantified. In few of the instances though, it is necessary to abandon

the results provided by noise modelling methods, and to refer more advanced analytical

methods or pursue an alternative to predictions as a basis for informing the assessments.

The limitations of the noise modelling methods, and possible alternative methods, are

discussed further in subsequent sections.

1.5 Models in general use and their intrinsic limitations and risks

1.5.1 Practical Engineering Methods:

The method adopted by these noise models includes the calculation of noise levels

by adding the individual contributions that each sound attenuation factor has on noise

transmission. The common factor in all these models is that they are mainly based on

experimental results. In general, they are simple, user-friendly and easy-to-use.

1.5.2 Semi-Analytical Methods:

Semi Analytical methods maintain the same practical structure as engineering

methods discussed in the previous method, but these methods are based on simplified

analytical solutions of the acoustic wave equation rather than experimental results. The

practical engineering methods takes into account only averaged meteorological effects,

whereas these methods allow a better tracking of the influence of specific atmospheric

conditions on noise levels, such as upwind or downwind situations. The ray tracing

models methods amongst Semi-Analytical methods are the most popular method used for

noise modelling.


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1.5.3 Numerical Methods:

Numerical method group includes methods such as the Fast Field Program (FFP),

the Parabolic Equation (PE) and the Boundary Element Method (BEM). These methods

are constructed on the numerical solution of the wave equation. The Fast Field Program

(FFP) and Boundary Element Method (BEM) permits the calculation of sound

propagation over non-complex level terrain with any user-specified atmospheric

conditions. The Boundary Element Method (BEM) includes the effects of sound

diffraction due to large obstructions and more complex terrains. Possibly the most

influential current outdoor sound propagation numerical models are Euler-type finite-

difference time- domain models (see, e.g., D Heimann, “A linearized Euler finite-

difference time- domain sound propagation model with terrain-following coordinates”,

Journal of the Acoustical Society of America, vol. 119, issue 6, p. 3813, 2006).

The Fast Field Program (FFP) or "wave number integration method" provides the

full wave solution for the field in a horizontally stratified medium. The FFP method

provides an accurate solution of the Helmholtz equation, except within a wavelength or

so of the source, but is limited to systems with a layered atmosphere and a homogeneous

ground surface. Therefore, systems with a range-dependent terrain (either in terms of

ground impedance or terrain shape), or with a range-dependent atmospheric environment

(variable sound speed profile with range) cannot be modelled with the Fast Field Program

(FFP) method. This makes the model unsuitable for use over large distances or with

mixed ground conditions. Additionally, the computing time is often significant. Fast Field

Program (FFP) is not so proficient since the ground has to be uniform (flat) and

consistent (homogeneous), and the atmosphere is described by a succession of horizontal

layers (no range-dependency).

In comparison to the Fast Field Program (FFP) method, the Parabolic Equation

(PE) method (based on an approximate form of the wave-equation) is not restricted to

systems with a layered atmosphere and a homogeneous ground surface. The Parabolic

Equation (PE) method, Euler-type finite- difference time-domain models and the

Lagrangian sound particle model are the only present-day technique that can handle

environmental range-dependent variations.


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There are three boundaries to the Parabolic Equation (PE) method: PE algorithms

only give precise results in a region limited by a maximum elevation angle, ranging from

10° to 70° or even higher depending on the angle approximation used in the derivation of

the parabolic equation; the calculation time for a complete spectrum is often significant,

particularly for to the calculation of frequencies more than 600 Hz; scattering by sound

speed gradients in the direction back to the source is ignored. In simple words, a

parabolic equation (PE) is a one-way wave equation, taking into account only sound

waves travelling in the direction from the source to the receiver. As the sound speed is

usually a smooth function of position in the atmosphere, the one-way wave transmission

approximation is usually a good one, but, when turbulence is to be taken into account,

this limitation must be considered.

These hybrid methods can provide highly precise images of propagation effects

for distinct frequencies in certain conditions, they provide the basis for the 'reference

model' used to authenticate the engineering method produced by HARMONOISE, an EU

project which has produced methods for the prediction of environmental noise levels

caused by road and railway traffic. These methods are envisioned to become the

harmonized methods for noise mapping in all EU Member States. These methods have

been developed to predict the noise levels in terms of Lden and Lnight, which are the

harmonized noise indicators according to the Environmental Noise Directive

2002/49/EC. Since the techniques are computationally intense they are most usually

employed for 2D noise prediction. Additionally, these methods are not extensively

available within the common commercial software available for noise modelling.

In summary, numerical methods have much strength, mainly in correctness, and

weaknesses, mainly in practical application. None of these methods are capable on its

own of handling all possible environmental conditions (wind speed and/or temperature),

frequencies and transmission ranges of interest in practical applications. One method will

be more suitable than another for a specific problematic scenario, and thus selection of

the best numerical method must be situation specific. [31]

These numerical methods are enormously useful for analyzing the propagation

under specific meteorological conditions. The problem is that these numerical methods

yield results for only those precise conditions and give little sign of statistical mean


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values of sound levels. Furthermore, the user must provide considerable amounts of

information which sometimes difficult to generate, such as complete profiles of wind and

temperature.


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1.5.4 Hybrid Models:

Hybrid model methods are used for complex situations. The general principle of

using the hybrid methods is to solve the wave equation or Helmholtz equation to presume

the sound field. The method for solving the wave equation is generally tough to

implement due to the complication of the atmospheric-acoustic environment. In fact,

except for the very modest boundary conditions and uniform media (which rarely occur

in reality), it is not likely to get a complete analytic solution for either the wave or

Helmholtz equation, consequently it is essential to use numerical methods. Several

different types of solution for the sound field have developed over the past few decades:

ray tracing provides a pictorial representation of the field, the Fast Field Program (FFP) is

precise but computationally rigorous and the Parabolic Equation (PE) is an

approximation to the wave equation that has been solved using explicit and implicit finite

different schemes.

1.5.5 Ray-Tracing Models

Ray –tracing models are quick to calculate and providing a pictographic

representation, in the form of ray diagrams, of the sound field. Additional advantages of

ray tracing are that the directionality of the source and receiver can be easily

accommodated, by introducing appropriate launch- and arrival-angle weighting factors;

and rays can be traced through range-dependent sound speed profiles.

Ray-tracing models are limited in capability only as a consequence of the

approximation leading to the ional equation. This enforces restrictions on the physics,

which in turn limit the applicability of ray theory. Two major irregularities can arise from

these limitations: predictions of infinite intensity in regions around caustics, and

predictions of zero intensity in shadow areas (where in reality sound energy will be

present through diffraction and scattering). Such difficulties can be overcome by

introducing different modifications, accounting to some extent for caustics and

diffraction. However, this technique presents problems when applied to propagation over

an irregular terrain in an inhomogeneous atmosphere.

The Lagrangian sound particle model is another method which reflects complex

terrain and meteorological fields which are regular with that terrain.


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Following Table 2 summarises and complements the above. For comparison

purposes the practical engineering method ISO 9613 has also been included.

Table 2: Features of commonly used environmental noise modelling methods

Characteristic

Engineering Hybrid modelling methods

ISO 9613 Ray

tracing FFP

Crank– Nicholson

Parabolic Equation

(CNPE)

Generalised

Fokker- Planck

Equation (GFPE)

Computing time Fast Fast Slow Slow Medium

Accuracy Poor Medium Exact Very good Good

Optimum

frequency range All High Low Low Low and Middle

Meteorological

conditions? No No No Yes Yes

Shadows and

caustics? Yes Yes Yes Yes Yes

Elevated sources No Yes Yes No Yes


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1.6 Reliability of the Environmental Noise Modelling

The reliability of environmental noise modelling is a very important question, but

one that is all too often addressed by potentially misleading statements about 'accuracy' in

the sense of the closeness between measured and predicted values.

A noise model represents an estimate of a 'snapshot' in time. As will be discussed

further in the following section, environmental noise fields tend to be inherently variable

in both time and space. This variability introduces a difficulty in defining the accuracy of

a model, as it is a function of the relationship between a constant predicted value and a

potentially widely varying noise level that could be measured in practice.

The value of a model cannot be measured by accuracy per se, but rather on a

judgment of its reliability as a tool in decision making, and this judgment should be made

according to the specific application and situation under consideration.

Providing that modelling studies are used with an awareness of the relative

benefits and limitations of predictions when compared to other possible bases upon which

a decision could be made, such studies can provide a reliable basis for decision making

purposes. In other words, a reliable model is one that is fit for purpose.

It is the purpose of this guide to assist all parties involved in these types of studies

to identify those situations where predictions can offer a reliable decision making tool,

and subsequently design case specific approaches to modelling that is focused on

producing reliable information that is fit for the purpose of the decision making exercise.

The requirement of fit for purpose information establishes an onus on practitioners to

deliver the outputs of predictive studies with accompanying contextual information that

enables decision makers to understand how such information can be used.


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Chapter 2

LITERATURE REVIEW

1) Traffic Noise In Small Urban Areas, M. Hadzi-Nikolova, D. Mirakovski , Z.

Despodov , N. Doneva (Faculty Of Natural And Technical Science Stip,

Macedonia, University) [1]

suggested that Traffic noise is often perceived as one of

the biggest environmental problems. In order to implement effective measures against

the traffic noise the information about its distribution – noise maps - is imperative.

Current regulations as much as scientific efforts focuses large metropolitan

agglomerations, although two-years (2010-12) research study in Stip (about 50.000

inhabitants) implicate excessive noise levels in the major part of city. Directed

monitoring and mapping using SoundPLAN 7.1 Noise and Air Pollution Modeling

Software, point to traffic as the principal community noise source, directly linked

with measured noise levels. The paper presents road traffic noise measurement and

mapping results in small but dynamic city of Stip, pointing to growing concern about

noise levels in similar environments all over South Eastern Europe.

2) Modeling and Mapping of Urban Noise Pollution with Soundplan Software, Ass.

Hadzi-Nikolova M, Ass. Prof. Mirakovski D, Ass. Ristova E, Ass. Ceravolo S. Lj,

(Faculty of Natural and Technical Science Stip, Macedonia, University) [2]

suggested that Noise maps are used to assess and monitor the influence of the noise

effects. Thus, the number of citizens who are annoyed can be determined. Noise map

scan be helpful in the planning and decision making processes for reducing the noise

pollution. In this paper, the noise map for parts of the city Stip, as a small urban area

in the center of the East Macedonia is delivered as a visual information of the

acoustic behavior. For this purpose, the SoundPLAN software is used. The small and

medium sized agglomerations (up to 100,000 inhabitants) as well as model generation

and data administration are performed by the SoundPLAN as single software. It is of

great importance that noise modelling software is flexible in the administration of

multiple noise scenarios and to be able quickly and reliably to turn these models into

noise maps. Software’s like SoundPLAN use advanced filtering algorithms so the

model can be reduced with a user defined tolerance. The SoundPLAN software offers


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many tools for data preparation, consistency checks and reports documentation. Many

of the tools go well beyond what could be expected in an acoustical simulation

program.

3) Comparison of Kilde Report 130 Rail Noise Modelling Predictions for

SoundPLAN 4.2 and 6.5, Mark Batstone, Rhys Brown and Jennifer Uhr [3]

suggested that Rail noise predictions in Queensland have historically been undertaken

using a DOS-based implementation of the SoundPLAN program. Rail noise levels

modelled using this DOS program have been validated with measured noise levels

throughout the history of its use. This DOS package has been superseded by

Windows-based implementations of SoundPLAN. Queensland Rail Network has

commissioned a study to compare the modelling results between the currently

accepted DOS-based version of SoundPLAN and the latest Windows-based

implementation. The outcomes of the study contained in this paper demonstrate why

QR Network is now able to accept Windows SoundPLAN results for rail noise

prediction projects within Queensland. Equivalent confidence in the modelled noise

levels reduces the amount of noise monitoring required at affected properties, leading

to a more efficient and sustainable use of available acoustical resources in

Queensland. Such reliable noise modelling results therefore enable more efficient

delivery of mitigation measures to sensitive areas than can be achieved with reliance

upon measurement results.

4) Generalizations and Accuracy in Community Noise Modelling – A Case Study

on Railway Noise in Burlöv Municipality, Kristoffer Mattisson [4]

describes that

when modeling noise it is important to consider the uncertainty in the method. There

are a number of sources of error that influence the result, such as the choice of

calculation method, software, data and user specific choices.

The purpose of this case study from Burlöv municipality in Scania, Sweden, was to

show the influence of such factors when modeling noise from railways with the

Nordic calculation method (Nordic council of ministers 1996) implemented in the

software SoundPLAN. The results were compared to a detailed modeling, and to

results from a previous large scale national noise mapping.


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The results show differences in the area size exposed to noise levels over Lden 55,

65, and 75 dB(A), when using different resolution, search radius, elevation, ground

softness and inclusion or exclusion of buildings. The difference in the number of

persons exposed to different noise levels is also presented.

The comparison of the detailed noise mapping in this study and the previous national

mapping shows large differences. The same calculation method and software was

used, but different input data and modeling options had been used. . The differences

in results shows that it might be important to make more detailed mapping of the

noise levels, if specific areas are to be evaluated. Modeling large areas, without

consideration to factor that might have a large local influence can give misleading

results on specific areas. However, the calculation time increases rapidly when noise

is modeled at a detailed level, and simplifications are often used in large scale

investigations.

The results from this case study underscore the need for standardized noise modelling

methods for comparisons between different areas and different time periods.

5) Further Comparison of Traffic Noise Predictions Using the CadnaA and

SoundPLAN Noise Prediction Models, Peter Karantonis , Tracy Gowen and

Mathew Simon, Renzo Tonin & Associates (NSW) Pty Ltd, NSW, Australia [5]

an

update of information presented in a paper written for the AAS Acoustics 2008

conference in Geelong, Victoria. In particular this paper presents results of traffic

noise modeling using CadnaA and SoundPLAN and compares both to noise

measurements for three large recent road projects in NSW. CadnaA is a well-known

and internationally accepted noise modelling package, and its acceptance and use in

Australia amongst acoustic professionals is growing fast. To assist the Australian

acoustical profession, the appropriateness and accuracy of CadnaA under Australian

conditions is currently being verified, and this paper presents actual project results for

this purpose. Unlike CadnaA, the SoundPLAN noise prediction model is extensively

used in Australia, particularly for road traffic noise predictions, and has been

recognised and accepted nationally by various regulatory authorities including the

major road authorities and environmental agencies. The aim of this paper is to

provide additional comparative data for predicted traffic noise levels using the


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Calculation of Road Traffic Noise (CoRTN) algorithms as implemented by

SoundPLAN and the CadnaA noise models for three large recent road projects in

NSW. These three projects offer features and characteristics that differ significantly

from the projects reported in the 2008 paper. Results from this study re-confirm that

the CadnaA noise modeling package is accurate and effective for modelling road

traffic noise in Australia.

6) Road Traffic Noise: GIS Tools for Noise Mapping and a Case Study for Skåne

Region, F. Farcaş , Å. Sivertun, Linköping University, Sweden [6]

states that

Traffic noise pollution is a growing problem that highly affects the health of people.

To cope with this problem one has to regulate traffic or construct noise barriers. In

order to implement effective measures against traffic noise the information about its

distribution – noise maps - is imperative. This paper presents our work in creating a

noise calculator software package implementation that can create noise maps. The

noise calculator is based on the noise model described in Nordic prediction method

for road traffic noise.

As a case study, the noise calculator was used to build both large noise maps for

Skåne region in south of Sweden and detailed noise maps for smaller areas in the city

of Lund.

7) Comparison of Traffic Noise Predictions of Arterial Roads using Cadna-A and

SoundPLAN Noise Prediction Models Michael Chung , Peter Karantonis , David

Gonzaga and Tristan Robertson, Environmental Acoustics Team, Renzo Tonin

& Associates Pty Ltd, Australia [7]

states that The use of Cadna-A is widely

accepted in Europe as a tool for predicting noise from various types of sources,

including traffic noise. However, traffic noise modeling using Cadna-A is still in the

early stages of acceptance in Australia and as such the appropriateness and accuracy

of Cadna-A for Australian conditions is currently being verified.

Unlike Cadna-A, the SoundPLAN noise prediction model is extensively used in

Australia, particularly for road traffic noise predictions, and has been recognised and

accepted nationally by various regulatory authorities including the major road

authorities and environmental agencies.


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8) Modeling and simulation of noise impact along a new railway section in Sao

Paulo, Brazil Maria Luiza Belderrain, Rafael Vaidotas and Wanderley

Montemurro, CLB Engenharia Consultiva [8]

discusses the modeling and

simulation of noise impact along a new railway section that is being in operation in

the urban area of Sao Paulo, Brazil. In order to authenticate the study, background

noise measurements were taken along the 13 km of the railway section during its

planning and implementation stage, covering 10 points near subtle receivers. Each

sampling measurement persisted about 15 minutes in both periods: day and night.

Next, the terrain was modeled, including streets and buildings in the Sao Paulo,

Brazil, and then simulation map of the existing noise levels was generated for model

calibration purposes. Latest SoundPLAN simulation software was used to construct

and calibrate the noise model with the Leq values obtained from the measurements.

Once the noise modeling of the environment was ready, then the focus were shifted to

the modeling of the train as a linear noise source. Noise measurements were

performed on similar trains in the other region in order to assess the noise levels

generated due to the train. The outcomes were then used to produce additional

simulation map where the train is moving at 90 km/h. The comparative analysis of

both simulation maps will finally allow the design of mitigating systems, such as

noise barriers aimed at decreasing the receivers' nuisance in the urban area of Sao

Paulo, Brazil

9) A study on noise level produced by road traffic in putrajaya using SoundPLAN

road traffic noise software, Abdullah, M.E., Shamsudin, M.K., Karim, N.,

Bahrudin, I.A., and Shah, S.M.R.[9]

to use SoundPLAN Software and Norsonic 118

Sound Level Meter in defining, investigating and determining noise scattering levels

in Putrajaya with the rules recommended by WHO. Software Application and Field

Surveillance methods were used in this study to assess and compare the noise levels

calculated by each method. From the test results conducted in the Putrajaya area, it

was observed that, there is no noteworthy difference of using SoundPLAN software

package and manual handling by Sound Level Meter in the field. This was well

supported by the outcomes and its findings which shows that t-stat is not surpassed

than critical by the T-test assumption study. There is a direct relationship between


21

urban noises and traffic volume. The finding of the study also specified that the

distance from the traffic is the main factor to the increase of noise level at Putrajaya.

From the analysis, a new noise contour map that covers some part of the districts has

been produced by using the SoundPLAN software package. These noise maps have

been particularized via software application that provide noise barrier to prevent noise

level from disturbing human activities. Based on the study conducted, it was

concluded that 30 % of the measurements from the study area were higher than 75 dB

(A) which was exceeded than the limit that recommended by WHO which can effect

hearing loss.

10) Traffic Noise Predictive Models Comparison with Experimental Data, Claudio

Guarnaccia*, Tony LL Lenza°, Nikos E. Mastorakis, and Joseph Quartieri**

Department of Physics “E.R. Caianiello”, Faculty of Engineering° Department

of Industrial Engineering, Faculty of Engineering University of Salerno [10]

describes the use of Cadna-A is broadly recognized in Europe as a tool for predicting

noise from various types of source (s), including traffic noise. However, traffic noise

modeling using Cadna-A is still in the early stages of acceptance in Australia and as

such the appropriateness and accuracy of Cadna-A for Australian conditions is

currently being verified.

Unlike Cadna-A, the SoundPLAN noise prediction model are being extensively used

in Australia, particularly for road traffic noise forecasts, and has been recognised and

accepted nationally by various regulatory authorities including the major road

authorities and environmental agencies.

The aim of this published paper was to compare predicted traffic noise levels using

the CoRTN algorithm which is being implemented in SoundPLAN as well as the

Cadna-A noise models for a proposed road and an existing major road. An

authentication of both noise modeling packages is also shown based on actual

measurements of traffic noise from an existing arterial road and compared to one

another.

Results from this study shows that the Cadna-A noise modeling software package is

as precise and effective compared to SoundPLAN model in modeling road traffic

noise.


22

11) Using Traffic Models as a Tool When Creating Noise Maps- -Methods used in

the EU-project QCity Pia Sundbergh, Research Engineer Royal Institute of

Technology (KTH) Stockholm, Sweden [11]

describes a method to adapt outputs of a

macroscopic transport model to a noise mapping software. The boundary has been

developed as a part of a study in the EU-project QCity where noise effects of traffic

control measures are examined. A noise map of a base scenario where no policy has

been applied is presented. Moreover a sensitivity analysis of speed data input is made,

where limits speed is used instead of modelled speed. It shows that speed limits give

up to 3 dB higher noise levels than use of modelled speed. We believe this is an

aspect to consider when official noise maps and action plans are created, as official

speed restrictions are often used instead of actual speed.

12) Problems of Railway Noise—A Case Study Małgorzata Szwarc, Bożena Kostek,

Józef Kotus, Maciej Szczodrak, Andrzej Czyżewski, Faculty of Electronics,

Gdańsk University of Technology, Gdańsk, Poland [12]

states that under Directive

2002/49/EC relating to the assessment and management of environmental noise, all

European countries are pleased to model their environmental noise levels in greatly

populated areas. Some countries have their own specific method to predict noise but

most have not created one yet. The recommendation for countries that do not have

their own model is to use an interim method. E.g. The Dutch SRM II scheme is

suggested for railways. In addition to the Dutch model, this paper describes and

discusses 3 other national methods. Moreover, inconsistencies between the

HARMONOISE and IMAGINE projects were analysed. The results of rail traffic

noise measurements are compared with national methods.

13) Industrial Settlements Acoustic Noise Impact Study by Predictive Software and

Computational Approach Claudio Guarnaccia, Joseph Quartieri, Alessandro

Ruggiero, Tony L. Lenza, Department of Industrial Engineering, University of

Salerno[13]

states that The usage of predictive software in environmental impact study

is very frequent. In this paper, an acoustic noise analysis of an operating industrial

plant is performed, both in the internal and in the external environment, with the aid

of two different predictive software. A measurement campaign is designed and

performed, according to quality procedure, in order to describe the internal acoustic


23

climate, to characterize the noise sources, that are the production machines and

operations, and to have reference values to be used in the tuning of the model. With

the source characterization, the internal simulations are performed and compared with

measured levels. Finally, the simulations of the external surrounding area are made,

in two different operating conditions, and combined with the internal simulations. In

this way, a procedure to perform complete predictions, both inside and outside the

plant, is given, showing, in the validation test, a good agreement with the measured

values.

14) Noise Dispersion Modelling in Small Urban Areas with CUSTIC 3.2 Software,

Marija Hadzi-Nikolova, Dejan Mirakovski, Todor Delipetrov, Pance Arsov,

Faculty of Natural and Technical Sciences, University “Goce Delcev” Stip,

Macedonia [14]

, states that noise pollution is genuine danger to human health and the

quality of life and presents one of serious factors that local agencies and state

authorities have to consider in development planning. Noise dispersion modeling can

be helpful in the planning and decision making processes for reducing the noise

pollution. Noise dispersion models are used to assess and monitor the influence of the

noise effects and for land-use planning as one of the method of effective and

economic noise control. In this paper Noise dispersion model has been developed

using the possibilities of low costs CUSTIC 3.2, Noise Pollution Modelling Software,

produced by the Spanish company Canarina, and according to noise level

measurements in the central part of Stip, in Eastern Macedonia that is typical, and

thus representative, of most smaller urban areas in this region.

15) Integrating A Noise Modeling Capability With Simulation Environments,

Raymond M. C. Miraflor , NASA Ames Research Center, Moffett Field,

California U.S.A [15]

describes the requirements for integrating a noise modeling

capability into air transportation system simulations. In order to address public

concerns, noise impact should be investigated with suitable models in simulation

environments. Coupling a noise modeling competence with these simulators will lead

to better understanding of what impact certain flight operations may have on local

peoples. Described within this paper are the general data requirements that a noise

modeling tool must receive from a simulator. At a minimum, the simulator must


24

provide data to the noise model that may be classified under environmental

conditions, flight path information including aircraft and engine enactment, and grid

set-up in order to analyze noise effect. An application of these requirements to the

integration of a noise model with an air traffic control tower simulator is presented.

Difficulties in obtaining and adapting these data types from the simulator are

scrutinized. It is expected that the details of these requirements may be used to enable

the integration of a noise modeling proficiency into other air transportation system

simulation environments.

16) Integrated Noise Model Route Optimization for Aircraft, Student team: Jessica

Kreshover, Phil Larson, Simmons Lough, Eric Merkt, Faculty Advisors:

Garrick Louis and Christina Mastrangelo, Department of Systems Engineering

[16] states that the effect of airport noise on populations in surrounding areas is an

issue that the Federal Aviation Authority (FAA) and airports continue to address.

Their research mainly shows why and how the FAA could use a Geographic

Information System (GIS) in combination with an optimization algorithm, combined

with the Integrated Noise Model (INM), to determine flight tracks that minimize the

effects of noise on populations surrounding airports.

17) Noise mapping as a tool for controlling industrial noise pollution, W J P Casas1,

E P Cordeiro1, T C Mello and P H T Zannin Universidade Federal do Rio

Grande do Sul, Departamento de Engenharia Mecânica, Rua Sarmento Leite [17]

describes the purpose of their work is to identify the contribution of noise from

external sources to the noise pollution generated by a industries, by comparing sound

pressure levels measured in its surroundings and those calculated by noise mapping

using software tool. In their assessment, a metal mechanical manufacturing plant was

selected and sound pressure levels were measured at separate points along two rings

around it, called receivers. The noise measurement data from the first ring were

entered into the SoundPLAN software to determine, through iteration, the factory’s

main noise sources. The SoundPLAN software then used this data to estimate noise

maps and sound pressure levels at the receiver’s positions in the second ring. Finally,

the contribution of noise from external sources to the overall noise produced by the

factory was determined by comparing the noise measured in the second ring with the


25

simulated data. The placement of partial barriers along some critically noisy walls

was found to be effective as a solution in controlling nighttime noise, safeguarding

that the sound level limit for this type of neighborhood, which is established by

technical standards for environmental noise as Leq = 60 dB (A), is not reached.

18) International Journal for Science, Technics and Innovations for the Industry

MTM (Machines, Technologies, Materials) 01/2012; VI:38-42 , Modeling and

Mapping of Urban Noise Pollution with Sound PLAN Software, Marjia Hazdi-

Nikoloava, Dejan Mirakovski, Emilija Ristova, Ljubica Stefanovska Ceravolo [18]

states that, noise maps are used to assess and monitor the influence of the noise

effects. Thus, the number of citizens who are irritated can be determined. Noise map

image are very helpful in the forecasting and decision making processes for

plummeting the noise pollution. In this published paper, the noise map for parts of the

city Stip (Macedonia), as a small urban area in the center of the East Macedonia is

delivered as a visual information of the acoustic behavior. For this purpose, the

SoundPLAN software is used. The small and medium sized as well as model

generation and data administration were performed by the SoundPLAN software. It is

of great significance that noise modelling software is flexible in the administration of

multiple noise scenarios and to be able quickly and reliably to turn these models into

noise maps. SoundPLAN use advanced filtering algorithms so the model can be

reduced with a user defined tolerance. The SoundPLAN software gives many tools

for data preparation, uniformity checks and reports documentation. Many of the tools

go well beyond what could be expected in an acoustical simulation program.

The overall findings of this literature review shows that the SoundPLAN noise

modeling package is as accurate and effective compared to other noise modelling

packages in modelling industrial noise pollutions predictions.

Also SoundPLAN is standards based software system offering industrial noise

calculations in accordance to all known international standards such as,

Europe/International: ISO9613 part 1, Germany: VDI 2714 / VDI 2720 / DIN 18005 /

TA-Laerm, Austria: OeAL 28, UK: BS 5228, Nordic: General Prediction Method for

Industrial Plants / Nord 2000, Japan: ASJ industrial model, USA: Industry model based

on TNM, WDI etc.


26

Therefore SoundPLAN noise modelling software is considered as competent, reliable

and generally accurate in modelling industrial noise worldwide.


27

Chapter 3

ENVIRONMENTAL NOISE MODELLING

METHODOLOGY

Many of the threats associated with the production of environmental noise are

inherent and cannot be precisely diminished economically. Therefore in general the

preeminent way to manage risks is as part of the whole process of using noise models.

The following guidance/process is a suggested approach for noise modeling.

This section is broken into the several key component elements that make up any

environmental noise prediction program, as represented in the following flowchart:

Figure 3: Common approach to environmental noise measurements

In the above figure all stages are presented with a return path to client

consultation and brief, since development through the analysis will produce information

about the noise environment that either contradicts earlier assumptions or that may not

have been available at the outset of the study and so may necessitate re-evaluation of the

forward investigation strategy. An important point is that environmental noise predictions

may not always be able to notify the assessment to an acceptable level of risk, so another

approach may be required. The understanding that a amended approach may be more

suitable may ascend at any point throughout the course of the investigation as new

information becomes available, from the initial review right through to the post-analysis

phase of the study. Following sub-section explains methodologies used in the

environmental noise prediction program.


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3.1 Step 1: Review the Requirement for Predictions

Whenever environmental noise predictions are planned, it is essential to have a

strong understanding of the reasons for the predictions, the importance of any decisions

shall be made on the basis of these predictions, any variable features of the sound field in

question that may represent sources of uncertainty (including longer term sources of

variability or change, as may be related to seasonal effects or future forthcoming

development that may inertly or directly alter the noise environment), and the likely

feasibility of conducting predictions.

It is at this point that attention must be given to the type of noise data that the evaluation

calls for, under the following categories:

• Absolute values, where the specific numeric value of the calculation is important

(e.g. comparison against known benchmark).

• Relative difference values (which may between sources or locations), where

developing attenuation strategies or complementing the design or findings of a

measurement study.

The relevance and reliability of any existing assessment data that is available

should be evaluated to determine whether this may negate the need for further

assessments. The limitations of any available existing data will need to be considered

against the difficulties that may face any attempt to develop new prediction data.

Finally, it is important at this point to identify any well-defined threshold values that

trigger significantly different assessment outcomes. The knowledge of such thresholds, in

conjunction with estimates of what predicted values that might be expected from the

study (see following screening exercise) is critical to determining the requirement for,

and scope of, subsequent detailed modelling exercises.

3.2 Step-2: Preliminary Screening Study

Preliminary screening prediction studies provide a means of assessing the

potential criticality of the prediction outcomes, and identifying critical source elements,

noise transmission paths, and noise assessment locations. These studies are comparatively

brief, and valuable for defining the scope of any upcoming work. Preliminary screening

study proceeds as follows:


29

1. Clearly define any thresholds at which contradictory assessment outcomes are

triggered. This might take the form of a threshold defined in a planning condition

or contract.

2. Pinpoint the assessment (receiving) locations.

3. Gather initial (preliminary sound source type and position) data.

4. Apply a very simple propagation assumption such as hemispherical spreading.

5. Produce very rough estimates of the expected noise levels at the identified

assessment locations for comparison with the thresholds or limit values.

In many of the instances, gathering information about the sound source (s) may be

problematic and difficult. In these cases, it can be possible to consider the separation

between the source and assessment locations, and then use this information to work back

to the magnitude of sound emission levels that would be needed to trigger differing

assessment outcomes.

Preliminary Screening studies then lead to one of the following outcomes:

No further studies are required, since the output information is already sufficient

to enable a decision to be made, and further detailed studies would not provide

any benefit to the study.

The available information suggests that further detailed studies can be averted by

a revised screening study.

A refined sound propagation model must be designed. The findings may provide

guidance as to the areas on which to focus.

Predictions with a risk level commensurate with project requirements cannot be

made and a different approach must be sought.

3.3 Step 3: Detailed Model Design

Given the extensive variety of uses of noise modelling, as well as the wide variety

of factors that influence environmental noise levels, there is no procedure for defining a

detailed model design that is suitable for every application. The process of developing a

detailed model design will often consist in a gradual refinement of the predictions of the

screening study. Since practical and technical constraints will often prevent the ideal

modelling approach from being pursued, the detailed design must identify the most


30

effective refinements that strike the best compromise between the resources required to

construct the model and the reliability of the outcome for decision-making purposes.

Reaching this compromise will need consideration of the criticality and financial impact

of the decision that depends on the assessment outcome.

The detailed model design will define the features of the sources and environment

whose description will have a significant effect on the calculated noise levels. These

features will often determine the type of algorithm required.

The following sections discuss the types of technical factor that should be

considered in developing the detailed model design.

3.3.1 Physical Environment

The first aspect of the physical environment to be defined is the scale of the

assessment area for which the detailed model needs to be developed. This will be based

on the assessment locations identified in the screening study.

The positional accuracy required decreases with increasing separating distance: a

10% change in separating distance equates in general to less than a ±1 dB change in the

calculated noise level.

The other aspects of the environment to be defined relate to the presence of

screening and reflecting surfaces, the location and extent of any absorptive ground

coverings, and the atmospheric conditions. The level of information required depends on

the sophistication of the propagation algorithm to be used.

In some instances, a decision that the assessment should consider atmospheric

conditions that are favorable to the propagation of sound will reduce the required

precision of details of screening structures and ground cover as their influences are

significantly reduced under such conditions.

The importance of precisely defining such attributes must be considered in the

context of the importance of small changes in calculated noise level to the assessment

outcome. However, when using engineering methods to calculate the influence of these

features, it must also be recognised that the validity of the methods is often restricted to

general characterizations, particularly when describing features such as acoustically soft

ground covers. It therefore does not follow that continually increasing the precision with


31

which the physical environment is described will necessarily translate to any increased

precision of calculated noise levels.

3.3.2 Sources

Based on the findings of the preliminary screening study it should be possible to

identify all sound sources that may together result in total noise levels similar to, or

higher than, the prevailing decision threshold or limit at the assessment locations. The

contribution of relatively low-power unscreened sources should not be neglected if the

model includes screening effects, as these may become significant if higher power

sources are screened.

A range of source attributes may need to be defined in more detail for the

purposes of the detailed model design. Consideration of the extent and nature of the

physical environment can simplify this definition. For example, in instances where there

is no screening and the separating distances are relatively small such that ground and

atmospheric effects are minimal, the calculation of total levels may not require any

information about the frequency profiles of the emission sources.

Attention must also be given to the range of emission levels that a source may

produce and the time span over which its emissions may vary. Correspondingly, the

relevant assessment time period must be clearly defined and related to the operating

patterns of the sources. For example, the standard most frequently used for rating

industrial noise in the UK defines time periods of 1 hour and 5 minutes for assessments

made during the day and night respectively. Therefore, sources with an ‘on-time’ or

pattern of time variation significantly less than the assessment period will need to be

directly factored into the emission rating. Conversely, sources which could display

differing emission levels in different assessment time periods will need to be rationalized

according to whether the assessment relates to average, typical upper, or worst case

conditions, as well as considering how the pattern of variations may relate to that of other

assessment sources or atmospheric conditions (e.g. is the highest noise level likely to

occur when favorable propagation conditions occur?).

Other important source characteristics such as frequency and directivity may also

need to be defined, depending on the likelihood of those characteristics being significant


32

to the assessment at the receiver location. For example, frequency information may be

important in terms of calculating the effect of ground coverings or screening, as well as

being a material consideration to the impact the noise may have at the location (i.e. is the

noise dominated by individual frequencies at the receiver location and therefore

potentially more disturbing than a wide-frequency source?).

In situations where barrier effects are to be factored into the calculation, careful

consideration must be given to the assignment of representative source heights for large

pieces of machinery. Conservative decisions may need to be made in order that

unrealistic screening benefits are not factored into the calculation. However this will need

to be balanced against the need for refinement of the calculation and may warrant closer

inspection of the sound radiation properties of the source.

3.3.3 Propagation Algorithm

In most practical assessments, environmental noise propagation calculations will

be performed using standard engineering methods such as ISO 9613 or CONCAWE. The

CONCAWE method was originally developed for noise impact from large industrial

(petrochemical) sites, but is now widely used in a range of environmental scenarios. For

an example of its use, click here. In the future, the newly developed procedures

formulated under the EU HARMONOISE and IMAGINE projects may be used. The use

of these engineering methods provides a relatively efficient means of producing

estimated noise levels that account for a significant level of detail. It must however be

recognised that these methods’ validated application is for the calculation of overall total

averaged noise levels under specified meteorological conditions. Not all of the

engineering methods are able to directly estimate noise levels that may occur in differing

meteorological conditions (e.g. ISO 9613 does not provide a method of calculating noise

levels that occur upwind of a source). In situations where the noise model is to account

for sources with very prominent and narrow frequency components, or where the

variations which occur for different meteorological conditions are of interest, engineering

methods should be used with a high level of caution. In some cases, the complexity of the

situation may warrant the use of more intensive scientific methods or, ultimately,

abandonment of predictions. To make informed decisions about the appropriate algorithm


33

to adopt requires background knowledge in the principles of sound propagation and an

overview of the relative merits and limitations of the various procedures.

3.4 Stage 4: Execute Calculations

The initial phase of the calculation is an extension of the detailed model design, in

the form of a review of the decisions made concerning the input information, through

testing elements of the calculation to gauge the sensitivity of the outputs to the precise

choice of input value, and thus identify where the quality of input information may need

to be revisited for further refinement.

Engineering methods can be implemented for many situations, but for large

numbers of source and receiver locations and/or complex propagation paths dedicated

software becomes practically essential. In particular, the use of such software enables the

rapid exploration of different scenarios that may be relevant to the assessment. Further,

such software often enables visualizations of the input data to be produced in order that a

user can readily check the plausibility of the input data. However, the use of such

software requires users to be fully aware of the manner in which it implements a

particular procedure and in particular what assumptions are being made. Additionally, the

documented descriptions of engineering methods are sometimes subject to a degree of

interpretation as to the correct procedure, and this is a source of variation between

different software packages. These considerations are such that proprietary modelling

software should not be used in the absence of a working knowledge of the calculation

routines.

At the outset of any calculation, the input data should be checked to confirm the

plausibility of the results, particularly where the latter are within close proximity to a

decision threshold or limit value. It is also essential to compare the predicted values with

the simple calculated values estimated during the screening study, and to check the

ranking of reported contributions attributable to each source against expectations.

3.5 Stage 5: Analyse and Report

Thorough reporting of environmental noise modelling is essential for users of the

outputs to understand the reliability of the information as a basis for decision-making

purposes. Important elements that the reporting must address are:


34

The assessment conditions that have been chosen as the basis for the assessment

and the reasoning behind the selection of these conditions.

The input information used to describe the sources, physical environment, and

propagation conditions, and how this input information relates to the chosen

assessment conditions.

Any uncertainties in the input information used for the model, how these

uncertainties have been rationalised in the modelling, and the significance of their

effect on the calculated values.

The choice of algorithm used to predict noise levels and the reasoning for its

choice, as well as any known limits associated with the method and assumptions

incorporated in the package that implements the algorithm.

A discussion of the output findings in comparison to any prevailing decision

thresholds or limit values, including references to the propensity for varied input

data or calculation uncertainties to alter this comparison, and thus the assessment

outcome, as well as reporting of the potential changes in noise for other possible

assessment conditions (as may be judged by prediction, knowledge of algorithm

limitations, or measurement data).

Any recommendations for further work that could be carried out to address any

residual risks associated with reliance on the calculation data for decision- making

purposes.

3.6 Risks in Environmental Noise Assessment

3.6.1 Introduction

An important factor in the consideration of site specific noise modelling is the

strong influence of commercial and practical constraints which are more prevalent than in

strategic mapping. In these instances, the commissioning party with ultimate

responsibility for allocating timescale and budget resources may not be aware of the

available choices, nor appreciate the varying risks of different approaches. Given the

degree of flexibility and interpretation permitted by relevant assessment criteria that may

drive the requirement for predictive studies, industry expectations of what may be

involved in conducting a predictive study are understandably wide ranging. These factors


35

will often lead to a situation where the scope of a study will be limited or compromised

without proper regard to the consequential trade off in terms of the risk and significance

of an incorrect assessment outcome.

In the context set out above, the challenge for practitioners is to raise the end

user’s appreciation of the potential decision risk associated with different approaches, and

to develop tailored assessment strategies that strike an appropriate balance between the

scale of resources required for a predictive study and the costs (social, financial or

otherwise) and likelihood of an incorrect decision resulting from a compromised study.

To achieve such a balance requires the assessment design to 'begin at the end'; that is,

prior to developing an assessment strategy, consider the nature and scale of the decision

to be made, and how predicted noise data could be used to inform the decision. In some

cases, designing the assessment strategy in this way may lead to a number of possible

approaches to conducting predictions, or may ultimately conclude that predictions do not

represent a viable decision making tool (requiring either the available resources to be re-

considered, or evaluation of alternative methods of informing the decision). This type of

approach provides the opportunity to focus inevitably limited resources on the most

critical elements of a study that influence the decision for which the assessment is

intended to inform.

The above considerations highlight the need for noise predictions to be used in a

way that appropriately manages the risk of incorrect assessment outcomes. It is worth

emphasizing that there are two main risks when considering the implication of an

incorrect assessment outcome. The first and perhaps most commonly recognized risk is

that of an outcome where a prediction fails to represent the full scale of noise levels that

occur in practice, leading to a situation where environmental noise levels breach

acceptable levels with associated social and financial consequences. However, the second

and perhaps most frequently underestimated risk is that of the unnecessary development

costs (direct costs as well as those associated with lost development opportunities) of

incorrect assessments arising from a prediction study that overestimates noise levels

experienced in practice. The latter risk is an important consideration within the current

assessment framework where worst case approaches are frequently relied upon to address

the challenges and limitations that apply to practical environmental noise studies.


36

3.7 Risk, Variability and Uncertainty

Appreciating from the previous section how environmental noise models are

constructed and used, the next stage is to discuss the challenges associated with use of the

modelling in environmental noise assessment and identify how these challenges may

translate into assessment risk.

It is essential that the users have an appreciation of variability in environmental

noise and equally important to recognize the distinction between variability, uncertainty

and risk.

This section of the guidelines commences with a discussion of environmental

noise variability and the challenges it presents to any attempt to objectively rate a noise

field. Understanding variability in this way provides a basis for identifying the types of

factors that a noise modelling exercise should take into account.

The section then concludes with a discussion of the compounding factors related

to the use of predictions that can introduce a further risk of incorrect assessment outcome

if not properly understood.

By far the most important limitation to the use of models is the fact that it is

necessary in exercising them to make some selection of the environmental parameters.

Often, a model will be required to output a single figure and it is crucial to realise that

this figure is dependent on assumptions about, for example, weather conditions that will

rarely be realised in practice. Since the variation of output values with input condition

values is so large, a model may very well therefore give an answer far different to what is

experienced in reality.

Environmental noise fields exhibit very large variability in space and time. In the

UK, environmental noise assessment of commercial or industrial installations relies

heavily on comparisons between the specific noise (the noise attributable to the

installation in question) and the background noise (the underlying noise in the absence of

influence from the installation in question). Thus, these forms of assessment are burdened

by the challenges of dealing with variability in two distinct sound fields.

In terms of both the background and specific noise, changing source and

propagation conditions will give rise to changes in both predicted and actual sound fields.


37

The reflection of these changes in predictions or measurements is thus a representation of

real trends exhibited in the sound field. Table 3 gives examples of how background and

specific noise levels can vary:

Table 3: Significant causes of variation in environmental noise sound fields

Component Examples of component variations

Source Background noise

Changing natural sound source contributions e.g. diurnal and seasonal

variations in the composition of natural sound sources such as streams and

wind disturbed vegetation

Changing traffic sound e.g. hourly, daily, and seasonal changes in the

general traffic flow volume and composition, as well short term (wet or

dry) and long term (road surface degradation) changes in road condition.

Specific noise

Operational characteristics, e.g. continuous or intermittent operation,

cyclical operations, load settings, personnel dependent effects, demand-

driven operational intensity

Seasonal effects for sources enclosed in buildings, such as open windows

in summer

Directionally varying sound characteristics

Varying sound characteristics and features such as tones and impact sound

Transmission Position dependent sound propagation, e.g. varying separation distances

due to sound source movement, varying degrees of sound path screening

according to source and receiver location, and localized

The variability of environmental noise fields presents the most critical challenge

to any attempt to rate the field by prediction. It raises the question of how an objective

rating of a sound field in one set of conditions may relate to those occurring in other

conditions. Further, the variation patterns of a sound field may be a very important

consideration to the assessment. The use of well-intended measures to suppress the

degree of variability exhibited in objective ratings may in fact undermine the validity of


38

an assessment finding by failing to recognize how actual sound variability may influence

the decision making process. For example, two separate sound fields each characterized

by identical average noise levels could invoke very different assessment outcomes if one

of the fields was characterised by constant levels consistent with the average value, whilst

the other field was characterised by widely varying levels with maximum levels

substantially above the average at certain times. This highlights the importance of

understanding the relative timing of the highs and lows exhibited by the background and

specific noise sources, e.g. does the highest background noise only occur when the

highest specific noise occurs? This is an important consideration for objective sound field

ratings that are often produced for downwind atmospheric conditions that favor sound

propagation from the source in question. Such an assessment condition cannot always be

assumed to be the condition in which the greatest difference between specific and

background noise levels occurs if the controlling background noise sources are also

affected by atmospheric propagation conditions outcomes are triggered, there is a

significant risk of an incorrect assessment being made. Whether the specific noise of the

installation in question is being compared against a background related limit or fixed

value limit, unidentified or misunderstood variability can create significant uncertainty as

to whether an objective sound field rating produced for one set of conditions will provide

a complete representation of the sound field. Subsequently, if unknown variability or

uncertainty overlaps some threshold value at which different assessment

A related issue is that available prediction methods are limited in the range of

conditions which they can model: for example, some engineering methods only enable

the calculation of noise levels which occur under downwind conditions. Given the

reliance on knowledge of the background and specific noise for the assessment of

commercial or industrial installations, it is important to recognize how each sound field

may vary. Importantly, when evaluating appropriate conditions for which an assessment

should take account of, it is necessary to identify any relationships that may exist

between the variability’s of the background and specific noise fields.

The importance of such relationships can be seen from Figure 3. This

demonstrates how the combined effects of variability in both sound fields can lead to

critical regions where the ability to discern the causes of variability becomes significant.


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In this example assessment, where the priority is to determine if the specific noise

exceeds the background noise, the critical region occurs when the range of specific and

background noise levels overlap. The situation therefore arises as a result of the

combination of two factors; the relative magnitudes of the sound levels and the extent to

which each may vary. An important consequence is that, outside the critical zone, the

specific and/or background noise levels may exhibit even higher degrees of variability

but, due to the increased relative difference between background and specific noise

levels, this increased variability may have no impact on the assessment outcome. In

summary, outside of the critical zone, there is no risk of incorrect assessment outcome

despite potentially high levels of variability, even if the sources of this variability are not

known. However, within the critical zone the risk of incorrect assessment outcome

becomes significant as long as the sources of variability remain unknown.

Figure 4: Indicative sound level versus distance chart depicting increasing

variability with distance from source

It is important to emphasise the importance of understanding the relative timing of

the highs and lows exhibited by the background and specific noise sources, e.g. does the


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highest background noise only occur when the highest specific noise occurs? This is an

important consideration for objective sound field ratings that are often produced for

downwind atmospheric conditions that favour sound propagation from the source in

question. Such an assessment condition cannot always be assumed to be the condition in

which the greatest difference between specific and background noise levels occurs if the

controlling background noise sources are also affected by atmospheric propagation

conditions.

Whether the specific noise of the installation in question is being compared

against a background related limit or fixed value limit, unidentified or misunderstood

variability can create significant uncertainty as to whether an objective sound field rating

produced for one set of conditions will provide a complete representation of the sound

field. Subsequently, if unknown variability or uncertainty overlaps some threshold value

at which different assessment outcomes are triggered, there is a significant risk of an

incorrect assessment being made.

3.8 Factors Affecting Risk in Environmental Noise Predictions

The preceding section sets out the challenges facing any attempt to objectively

rate an environmental noise field. In this section attention is now directed to the

challenges and risks specifically relating to objective ratings derived from predictions.

The origins of this risk can be described by two broad categories described as follows:

• Assessment Conditions: The inherent variability of environmental noise levels

presents the challenge of determining which source and propagation conditions

should be used for the assessment. This challenge applies equally to measurement

and prediction based studies. However, in the case of environmental noise

predictions there will often be less information to quantify the full range of

variability that may be expected in practice. Also, there is often a restricted range of

conditions for which the available prediction methodologies can offer meaningful

representations For example, some engineering methods only enable the calculation

of noise levels which occur under downwind conditions, whilst in some cases,

upwind conditions may be equally or more important.


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• Prediction Quality: The accuracy with which the prediction model determines

the noise level that would occur in practice for the exact physical conditions that

the model is attempting to represent. These inaccuracies relate to the limitations

of the input data and to the ability of the chosen sound propagation algorithm to

represent actual transmission conditions.

In both of these two broad categories, the limits of application and accuracy of

practical prediction techniques represent important considerations. These limits

are discussed below in the context of the input data used to construct the models,

available calculation models, proprietary software packages that implement these

calculations, and the practical constraints typically encountered in dealing with

these challenges.

3.8.1 Input Data

The key input information to most noise prediction studies is a representation of

the sound emission level and character of the sources to be investigated. Where

available, such information might comprise a test emission level deduced from

measurements made in relatively controlled environmental and operational

conditions. In other instances, emission characteristics may be deduced from

empirical relationships according to the type of equipment under consideration

and some aspect of its performance rating. In cases where no such information is

available, an estimate may be acquired from field measurements of an installed

item of plant. In all cases, the data will be a relatively simple representation of the

total emission and character of a very complex sound-comp generating

mechanism. The total emission of a machine will comprise many contributions

from individual components which have their own sound emission characteristics.

This complexity introduces some important factors to bear in mind when

considering the representation provided by sound emission data:

• Source directivity: Many types of noise sources have directional characteristics

such that the noise level observed at a constant distance from the machine will

vary according to the orientation of the machine. These characteristics are often

not evident in sound emission data, and it is usually very difficult to establish the


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extent to which the emission in a particular direction may vary from the average

quoted value.

• Source geometry: The distribution of the individual component noise sources

associated with a complex machine will affect the pattern of the noise field that

emanates from it. This is relevant to the source directivity as described above, but

also has an important relationship to how the source’s sound field will interact

with the surrounding environment. For example, a large piece of equipment may

be almost entirely visually obstructed from a receiver location of interest by a

solid screen; the question as to whether sound levels at the receiver location will

be significantly reduced by the obstruction will be highly dependent on whether

or not the exposed portion of the machine is a significant source of the machine’s

total sound emission. As with directivity, the distribution of sound sources about a

complex machine will often be very difficult to establish from the available

emission data.

Source input versus actual emission level and character: the actual emission level

and character of the item of plant being modelled may vary from the input

representation for a wide variety of reasons including manufacturing variations

between the tested and installed item of plant, sensitivity of the installed plant

item to mounting conditions and variations in the operational duty of the installed

machine.

• Representation of the physical environment: An accurate representation of the

physical dimensions of all acoustically significant features of a potentially large

assessment area can be very problematic. The additional challenge is then the

assignment of acoustical properties to surfaces that absorb, impede and reflect

sound to varying degrees. Accounting for the complexities of the terrain and built

environment generally requires simplifying assumptions to be made in order that

they can be included in a noise model. Subtle factors and variations not

represented in the estimation can lead to differences between predicted and actual

noise levels, particularly where the influence of certain environmental features

have interdependencies (e.g. the effect of screening and wind conditions cannot

be considered in isolation from each other).


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The complexity further extends to the atmosphere through which the sound must

propagate. This is discussed in further detail in the following section.

3.8.2 Algorithms for Outdoor Sound Propagation

The ability of mathematical algorithms to accurately represent sound propagation

has been the focus of considerable research, particularly given the role of noise prediction

as an integral assessment tool in the fulfilment of the European Noise Directive (i.e. EU

Directive 2002/49/EC, which requires member states to produce noise maps and action

plans for urban areas and major transport infrastructures, including roads, railways and

airports). Predictive algorithms vary widely in sophistication from commonly employed

engineering methods (empirically based) through to more complex scientific methods

that are mostly employed for specialist research applications. Engineering methods offer

the benefit of robust and practical computation, but are generally limited to the prediction

of longer term average A- weighted noise levels, and exhibit increasing uncertainty when

attempting to evaluate noise fields with complex sources and/or propagation conditions.

At the opposite end of the spectrum, scientific methods can provide significantly greater

accuracy for complex situations, but generally only for very specific and limited

scenarios, and are computationally intensive to an extent that limits their viability as a

practical assessment tool.

The complexity of atmospheric conditions and the impracticability of measuring

all the relevant environmental parameters throughout the sound propagation path, require

that several assumptions and simplifications in the models are adopted. This set of

assumptions and approximations has led to the existence of a variety of methods to

mathematically represent sound propagation. Generally, all these methods can be

classified as one of the following three categories:

Practical engineering methods

Approximate semi-analytical methods

Numerical methods

3.8.3 Environmental Noise Modelling Proprietary Software’s

There are many practical complications of applying predictive algorithms to the

computation of a large number of sources over extensive areas; noise modelling


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proprietary software packages is most commonly employed to generate predictive noise

models. These packages provide an efficient and organised method to the gathering of

input data, and then offer options to execute many predictive algorithms to generate

calculated noise levels over a wide range of receiver locations. The improvement of these

software packages involves the conversion of standard predictive algorithms (such as ISO

9613) into computational code. These software packages will often implement efficiency

algorithms that enable users to strike a balance between likely computational accuracy

and calculation time, in order to achieve practical computation times. Whilst such aspects

of proprietary packages are clearly advantageous for practical assessment purposes, there

is limited data available for the user to understand the extent to which such efficiency

techniques may compromise the anticipated value. Experience of numerous commonly

implemented packages has indicated that variations in the approach to efficiency can

potentially amount to significant variations in calculated outputs. Presently, there are no

any international or British Standards that provide a user with any certification of a

proprietary package’s accurateness in applying a given predictive algorithm, and the

trustworthiness of a particular package will therefore often derive from brand

acknowledgment. This contrasts with objective studies based on measurements that need

that any sound level meter used for such an exercise to be calibrated and demonstrated to

attain agreement with set reference conditions when verified in a laboratory scenario.

1) SoundPLAN v 7.2 Industrial Noise Indoors / Outdoors

SoundPLAN® was one of the very first noise modeling software’s on the market,

debuting in 1986. Due to its ever increasing popularity on the world market, an

international office was opened in 1999. The core of our business was and is the

prediction of noise in the environment. Noise emitted by various sources propagates and

disperses over a given terrain in accordance to the laws of physics. Worldwide, many

governments and engineering associations felt the need to algorithmize the principles of

acoustics so that different engineers assessing the same scenario would get reasonably

close answers.

The SoundPLAN industrial noise modeling is unique. All questions of frequency

dependent noise can be simulated whether it is purely an indoor problem, a receiver

outside that needs to be assessed for outside sources, or a complex problem with the


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source inside an industrial building and a receiver on another building. The simulations

inside industrial buildings are completely integrated with the transmission through the

outer walls and the propagation into the environment.

Sources for the industrial model can vary between point, line and area sources.

The sources can be described with the sound power [Lw] (for a mean frequency, octave

or third octave band), with a 2D or 3D directivity and with a time history defining the

strength of the source within the 24 hours of the day. Routines to convert sound pressure

levels with a given reference distance into sound power and frequency filters are part of

the SoundPLAN tools.

For line and area sources, the sound power can be entered for the entire source (as

per unit) or as a power per meter/square meter of the source. An excavator in a

construction site is a perfect example of a per unit area source. Per meter is a sensible

entry for a conveyor belt that emits a certain sound power every meter of its length,

whereas the per unit setting would be preferred for a fork lifter with a known sound

power that is moving along a defined path.

Figure 5: Industrial Noise Indoors and outdoors with Noise Transmission


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Calculation Standards for Industry Noise

SoundPLAN is standards based software system offering industrial noise

calculations in accordance to all known international standards.

Europe/International: ISO9613 part 1

Germany: VDI 2714 / VDI 2720 / DIN 18005 / TA-Laerm

Austria: OeAL 28

UK: BS 5228

Nordic: General Prediction Method for Industrial Plants / Nord 2000

Japan: ASJ industrial model

USA: Industry model based on TNM, WDI

The calculations for indoor noise problems are based on the VDI 3760.

Although all standards for industry noise intend to simulate the propagation of

noise from a source to a receiver (described by sound power, frequencies, directivity and

hourly history), they are each unique. There are differences in what is simulated and how

the physical parameters of the transmission path are described. Some of the standards

intend to give the worst case answer (i.e. simulate a downwind situation or slight morning

inversion conditions), some intend to simulate the annual average conditions, and some

specialize in describing the momentary situation with wind and weather of current

conditions. Episodes with multiple weather scenarios linked together can form annual

average conditions. Please read each standard text carefully in order to understand the

intent of each particular standard. For describing the physics, there are 3 basic models.

Some of the models share very similar parts with small, but important variations. VDI

2714/2720, the General Prediction Method for Industrial Plants, OEAL28 and the

ISO9613 with variations share the same roots and concepts.

CONCAWE was designed to simulate the propagation for a specific weather

scenario. It was derived from measured data and uses 3rd order polynomials to describe

the effects of wind, stability and ground effect. Unfortunately, these formulas all lose

their validity below 100 meters. SoundPLAN uses the formulas, but derives answers for

closer sources by linear interpolation of the value calculated at 100 meters.


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The new Nord 2000 uses new concepts and features a phase correct reflection of

the wave on the ground. A frequency dependent Fresnel Ellipsoid marks the influence

zone for the propagation. Every object inside this zone has an influence on the results.

Because of this, simple cross-sections are no longer useful for describing the propagation

path.

2) Predictor-LimA Software Suite Type 7810

A software bundle for environmental noise projects that integrates the intuitive

Predictor™ and the flexible LimA™ software into one powerful, state-of-the-art package

- providing an efficient solution for any project.

In the suite, Predictor and LimA can be used as stand-alone applications, or as one

integrated application by using the LimA-Link option in Predictor. Because Predictor and

LimA both use the same fast LimA calculation cores, there is no difference in calculation

speed or calculation capacity.

Predictor has a fast learning curve, enabling you to work efficiently, even for

infrequent users. Modelling is easy with its intuitive and unique multi-model view and

unlimited undo/redo functionality. Being powerful and intuitive with macros for

automated model changes, you can model real life quickly, easily and accurately, even in

complex situations.

LimA is highly configurable. Its openness eases integration with external data

sets, calculation components and other systems. It includes powerful macro functionality

with automated data manipulation and advanced geometric handling for modelling

without the need to use other software such as Geographical Information Systems (GIS).

The suite offers three basic implementations:

1. Predictor: For most projects that require the calculation standards supported by

Predictor, its intuitive user-interface allows them to be handled quickly and easily.

2. LimA stand alone: For calculation standards not supported by Predictor such as

German and Eastern European standards.

3. LimA integrated into other (GIS) systems: For implementing environmental

noise calculation and analysis functionality in other systems.


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Uses

Create and calculate models with the predictor system on multiple PCs on the

network with only one license

Environmental noise mapping, management, action planning and impact

assessment

Fulfillment of European Commission directives such as Environmental Noise

Directive (2002/49/EC) in accordance with Guidelines on Revised Interim

Computation Methods (2003/613/EC)

Fulfillment of the IPPC Directive (2008/1/EC) and similar

Educational purposes

Integration into other (GIS/management) systems

Features

Fast learning curve, even for infrequent users

Accurate and intuitive modelling for complex situations

Fast calculations

Time-saving integrated bookkeeping for model data and results

Powerful result analysis and what-if scenarios

Integration in environmental management, traffic management and Geographical

Information Systems (GIS) as noise calculation core

Automated reverse engineering and instant noise maps using measurements

Automated workflows (including calculation, plots, etc.)

3) CadnaA at a glance

Whether your objective is to study the noise Emission level of an industrial plant,

a mall including a parking lot, a road and railway scheme or even of an entire town with

airport

Industry

Plan noise reduction measures

Maintain emission data in convenient libraries

Compare different scenarios with variants

Review your model with various sophisticated 3D features


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Calculate outdoor sound propagation based on sound sources inside

Take advantage of the data exchange with the indoor noise calculation software

Bastian™

Calculate the uncertainty with standard deviations for emission and propagation

Road & Railway

Compare different planning scenarios

Automatically optimize the barrier next to a street or railway

Visualize and auralize noise reduction scenarios

Efficient project management with object tree and variants

Automatically intersect object data with DTM

Check your model via visualization of all propagation tracks

Noise Mapping

Accelerate your calculation time with distributed calculation and multithreading

Employ all RAM available with 64-bit technology

Efficiently merge various data types using more than 30 different import formats

Access and alternate all object attributes within the 3D View

Analyze your model using various noise assessment techniques

Verify your model via quality assurance while using acceleration techniques

Profit from a maximum level of complexity in detail and the highest possible

clarity when working on large-scale segments.

Industrial Expert System

(Option SET)

Automatically generate sound power spectra based on technical system

parameters of a sound source (e.g. electric power in kW, volume flow in m3/h,

rotation speed in rpm)

Facilitate your work utilizing 150 predefined modules for technical sound sources

such as electric and combustion engines, pumps, ventilators, cooling towers, gear

boxes etc.

Model complex systems including transmissions by combining sources (e.g.

ventilator with two ducts connected)


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Aircraft

(Option FLG)

Calculate noise emitted from civil and military airports based on the calculation

methods AzB 2008, AzB (1975), ECAC Doc.29 or DIN 45684-1

Cover the most relevant procedures for aircraft noise assessment at European and

international level

Perform an overall assessment of the total noise exposure including, road, railway

and aircraft noise

Use radar data and group classification according to ICAO code to calculate the

aircraft noise

Air Pollution

(Option APL)

Calculate, assess and present air pollutant distribution according to the

Lagrangian particle model AUSTAL2000 (other models are being integrated)

Combine the assessment of measures in the context of noise and air quality

mitigation plans

Enjoy the usability and calculation power of CadnaA also while modeling air

pollutant distribution

Apply all import formats without any additional costs

4) Traffic Noise Model

Prior to the release of the FHWA TNM, the FHWA Highway Traffic Noise

Prediction Model (FHWA-RD-77-108), or "108 model," was in use for over 20 years.

Although an effective model for its time, the "108 model" was comprised of acoustic

algorithms, computer architecture, and source code that dated to the 1970s. Since that

time, significant advancements have been made in the methodology and technology for

noise prediction, barrier analysis and design, and computer software design and coding.

Given the fact that over $500 million were spent on barrier design and construction

between 1970 and 1990, the FHWA identified the need to design, develop, test, and

document a state-of-the-art highway traffic noise prediction model that utilized these


51

advancements. This need for a new traffic noise prediction model resulted in the FHWA

TNM.

The core vehicle noise emissions database for the "108 model" was collected in

the mid-1970s. Because of the age and associated limitations with this database (e.g., no

data for vehicles on grade or vehicles subject to interrupted-flow conditions), it was

essential that a state-of-the-art, nationally representative database be developed for the

FHWA TNM. A state-sponsored, pooled-fund effort supported the development of the

national reference energy mean emission levels (REMEL) database for the FHWA TNM.

Between 1993 and 1995, data were collected for over 6000 vehicle pass-byes at over 40

sites in 9 states across the country.

The FHWA TNM (Version 1.0) was released in March of 1998. The model was

the culmination of six years of extensive research. It included a new/expanded vehicle

noise emissions database and state-of-the-art acoustical algorithms. After the release, a

survey was distributed to FHWA TNM users to allow user input for program Graphical

User Interface (GUI) enhancements and bug fixes. This list was prioritized, and many of

the enhancements/bug fixes were incorporated into FHWA TNM Versions 1.0a, 1.0b,

and 1.1. Version 1.1 also included a major improvement to the computational speed of

the program, upgrading the architecture from 16 to 32-bit. Unfortunately, this version

also introduced some new bugs. Version 2.0, released in June 2002, focused on removing

Version 1.1 bugs, while maintaining the faster computational speed. Version 2.1, released

in March 2003, fixed additional bugs and included over 20 enhancements to the TNM

GUI. Version 2.5, released in April 2004, is the first version of the software, since the

original release, with major improvements to the acoustics.

The FHWA TNM® is a registered copyright and trademark.

The FHWA TNM contains the following components:

Modeling of five standard vehicle types, including automobiles, medium trucks,

heavy trucks, buses, and motorcycles, as well as user-defined vehicles.

Modeling of both constant-flow and interrupted-flow traffic using a 1994/1995

field-measured data base.


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Modeling of the effects of different pavement types, as well as the effects of

graded roadways.

Sound level computations based on a one-third octave-band data base and

algorithms.

Graphically-interactive noise barrier design and optimization.

Attenuation over/through rows of buildings and dense vegetation.

Multiple diffraction analysis.

Parallel barrier analysis.

Contour analysis, including sound level contours, barrier insertion loss contours,

and sound-level difference contours.

These components are supported by a scientifically founded and experimentally

calibrated acoustic computation methodology, as well as an entirely new, and more

flexible data base, as compared with that of its predecessor, Stamina 2.0/Optima. The

database is made up of over 6000 individual pass-by events measured at forty sites across

the country. It is the primary building block around which the acoustic algorithms are

structured. The most visible difference between the FHWA TNM and Stamina

2.0/Optima is the FHWA TNM's Microsoft Windows interface. Data input is menu-

driven using a digitizer, mouse, and/or keyboard. Users also have the ability to import

Stamina 2.0/Optima files, as well as roadway design files saved in CAD, DXF format.

Color graphics will play a central role in both case construction and visual analysis of

results.

5) CUSTIC software • noise pollution modelling

CUSTIC is software for noise pollution modelling. The program calculates the

noise level in each point of the space considering each one of the sources and the

conditions of the atmosphere. The system of simulation of processes of dispersion that

CUSTIC has, offers to the beginner and the expert programmer, a quick and practical

system to evaluate noise pollution. The program is based on the operating system

Microsoft WINDOWS where one works intensively with the mouse and the graphic

windows.


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It is ideal for environmental impact assessments, environmental consultancy

services and environmental engineering.

With this application you will be able to import images and pictures (previously

saved BMP files) and Google maps. These images will be background pictures and

images for your program window. Many programs and computer applications

(AutoCAD, 3d Studio, ArcView,) export BMP files. You will be able to load pictures and

images generated by these programs.

This software can also be used for risk studies and safety in industries.

Advantages noise pollution modelling

Without considering the experience that the user possesses in programming

languages or in the use of simulation tools, in few minutes he will be able to have the first

results.

With this application you will be able to export your simulation results (BMP

files). These images will contain the background picture (map) and your simulation

results. Many programs and computer applications (AutoCAD, 3d Studio, ArcView, MS

Power Point, and MS Word) can import your saved BMP files.

It works in Cartesian and geographical coordinates and the results can be exported

in Microsoft EXCEL csv files. It is possible to import the CUSTIC generated data in GIS

systems, as Arc Map or ArcView.

CUSTIC carries out temporal averages (daily, monthly or annual) so that you can

calculate the concentration average in each point of the affected area.

CUSTIC works with two different models: the ISO-9613 for punctual sources and

the classical CUSTIC model.

It is possible to obtain XY and XZ noise maps.

6) Integrated Noise Model (INM)

Global Standard Modeling Tool for Aircraft Noise Impacts

ATAC is the primary software developer and system integrator of the Integrated

Noise Model (INM). The INM is the Federal Aviation Administration's (FAA's) standard

computer model for assessing aircraft noise impacts in the vicinity of airports and over


54

National Parks. It is the required noise assessment tool for airport noise compatibility

planning under FAR Part 150 and for environmental assessments and impact statements

under FAA Orders 1050 and 5050 in compliance with the National Environmental Policy

Act.

Over 1,000 users in over 65 countries use the INM to assess noise impacts caused

by changes in airspace structures, proposed runways or runway configurations, revised

aircraft routings and flight profiles, modified air traffic control operational procedures,

and revised traffic demand levels or fleet mix.

The INM computer program calculates noise exposure contours in the vicinity of

airports by using a large database of aircraft flight performance and acoustic data along

with airport-specific user-input data. The INM graphical user interface provides a

versatile, user-friendly, windows-style means for users to specify operational scenarios to

be modeled and to review the noise results.

Application of the INM includes:

• Assessing changes in noise impact resulting from new or extended runways or

runway configurations

• Assessing new traffic demand and fleet mix

• Evaluating other operational procedures

• Fulfilling statutory requirements defined in FAA Order 1050.1E, Policies and

Procedures for Considering Environmental Impacts; Order 5050.4A, Airport

Environmental Handbook; and Federal Aviation Regulations (FAR) Part 150,

Airport Noise Compatibility Planning

Features

• The model supports 16 different pre-defined noise metrics from the A-Weighted,

C-Weighted, and Perceived Tone-Corrected noise level families.

• User-defined metrics may also be created from these families, such as the

Australian version of the Noise Exposure Forecast.

• The main outputs from the INM model are noise exposure contours that are used

for land use compatibility mapping.


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• The model calculates predicted noise levels at specific sites, such as hospitals,

schools, or other sensitive locations and provides detailed information for the

analyst to determine which events contribute most significantly to the noise at

each location.

Benefits

The Integrated Noise Model provides significant benefits to the user, including:

• Meeting the requirements for airport noise compatibility planning under FAR Part

150 and for environmental assessments and impact statements under FAA Orders

1050 and 5050 in compliance with the National Environmental Policy Act

• Use of the world's most extensive publicly-available database of aircraft noise and

flight performance data

• The ability to export graphical noise analysis data to commercially available

Geographic Information System (GIS) software such as ESRI Arc Explorer and

MapInfo

7) IMMI - The Noise Mapping Software

IMMI covers a wide range of applications ranging from noise mapping to air

pollution modelling. IMMI integrates both noise and air pollution in a single software

package. In this section we will concentrate on those features of IMMI that were

specifically designed for noise mapping and noise prediction. In these fields, IMMI is one

of the leading packages worldwide. With its modular design and price-list, IMMI can be

tailored to the user's needs and budgets - ask for details.

IMMI is continuously adapted to meet the requirements of evolving regulations

and standards. Depending on the calculation method, IMMI calculates Leq, Lday,

Levening, Lnight, Lden, LAmax, L10 and other sound or statistical indicators.

Currently IMMI can be equipped with:

• Noise calculation methods for road traffic noise, railway traffic noise, air

transport noise and industrial / recreational noise

• More than 20 national and international noise calculation methods


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Noise Mapping gained additional importance with the arrival of Directive

2002/49/EC which is related to the assessment and management of environmental noise.

IMMI is equipped with a full set of functions to produce Strategic Noise Maps of major

roads, major railways, major airports and major agglomerations.

Noise propagation calculation methods according to 2002/49/EC: Road Traffic

Noise: XP S 31-133/NMPB+Guide du Bruit - Railway Noise: RMR-SRM II-1996 -

Industrial Noise: ISO 9613-2 - Aircraft Noise: ECAC. CEAC Doc. 29 and all European

national methods.

3 Packages are available! IMMI is available in any of the three following

packages, each of which carries a different price tag and more or less features.

• ##IMMI Standard is a comfortable entry-level into the world of noise mapping.

• ##IMMI Plus is the next step upwards to model, calculate, analyze and present

projects of varying size.

• ##IMMI Premium is the ultimate professional tool for noise prediction and large-

scale noise mapping.

8) Environmental Noise Control –Behrens and Associates

Using this noise modeling software, engineers can predict the sound levels at

specific points and the surrounding area to observe the impact and sound propagation of

sound sources on the environment.

A technician from ENC collects sound level measurements of sound sources, and

our team of engineers uses the collected data to model the sound sources. Building and

barriers that will affect noise propagation are added into the model. Calculations are

performed in an acoustical modeling program to determine the sound levels at specific

points determined by the client or by municipal codes. Our engineers perform further

calculations to determine any mitigation measures needed to comply with local noise

ordinances.

Engineers can use the software to design and optimize noise reduction measures,

such as enclosures and sound barriers.


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9) Noise3D online™

Noise3D online™ is an innovative web based noise calculation and prediction

software. A solution for architects, industrial planners and environmental experts working

on noise measures. Please have a look at our free trial version. Thereafter, when you

calculate you will pay a fee, no further obligations, no termination needs.

Why noise3D online? … easy to use, yet complete and comprehensive

Noise abatement is a key issue and effective measures are expensive. noise3D

online will help you become successful. With its fast processing engine you will iterate

calculations. This will reduce expenditures and cost. As a service you will avoid

investment and have flexibility. Noise3D online is fast, accurate, effective and practical.

The tool for noise control engineering.

Architects and planners concerned with noise control issues will avoid high

consultants cost and address calculation and mapping needs with noise3D online

themselves – as many calculations as you wish, not just two or three shots by the experts.

Features

• Very user friendly, easy to operate

• Built to estimate or predict environmental noise for planning, engineering or

control of industrial facilities

• Sound pressure levels calculated according to ISO 9613

• considers multitude of acoustic elements including ground effects, obstacles,

reflection, insulation calculates accurate results and creates compelling noise

maps

• Facilitates sound power level simulation Google Earth™ Pro as basis for plan.

Benefits

Acknowledged calculations method according to ISO 9613-2 robust and proven

calculation module of Kramer-Schalltechnik quality graphical 3D input accurate results

in table format compelling 3D noise maps immediate results.

10) SARNAM™ Noise Impact Software

Weapons noise compromises the Department of Defense’s (DoD) ability to

maintain access to resources necessary for military training and testing. Community


58

reactions to military noise include complaints, damage claims, legal action, political

pressure, and other efforts to curtail the noisy activity. Noise concerns have prompted

installations to relocate training, impose firing curfews (both time of day and day of the

week), and close ranges. Such short-term-solution decisions, if made without reliable

noise management technology, can needlessly hamper training mission execution and

ultimately impact soldier proficiency and survival. Noise impact assessment software can

guide planning decisions to minimize noise impacts on soldier and civilian health and

welfare. Impulsive noise from military weapons training and testing is not governed by

national laws; consequently, noise management consists of striking a balance between

mission execution and environmental quality. Reliable guidance regarding noise level

reduction under a wide range of conditions is arguably more critical than the absolute

accuracy of noise level predictions for specific conditions.

The military noise impact assessment software, or noise model, known as

SARNAM™ enables calculation and display of noise contours for small arms ranges.

The name SARNAM™ is an acronym for Small Arms Range Noise Assessment Model.

Input options include the type of weapon and ammunition, number and time of shots,

range size and structure, noise dose metrics, and assessment protocols. The model

accounts for muzzle blast and projectile sonic boom spectrum and directivity, which

facilitates accurate sound level prediction and interpretation of receiver response.

SARNAM™ noise level predictions are based on the mean expected value of noise level

metrics for mild downwind sound propagation conditions; this calculation is used in all

directions, which moderately over-predicts noise levels in some regions. SARNAM™ is

most useful as an environmental planning tool to address unwanted noise as an

environmental attribute in the community; it can be used to avoid siting new noise-

sensitive land uses in areas impacted by military noise and to guide mitigation of

environmental impacts of operational plans or new facilities.

The overall objective of this project was to validate and demonstrate the

SARNAM™ small arms noise impact assessment software under typical conditions. The

“validation” aspect of the project sought to test the accuracy of SARNAM™ by

comparing calculation results with comprehensive noise monitoring data to judge noise

level prediction accuracy. The demonstration aspect of the project sought to evaluate the


59

software utility and cost during realistic noise management consultation. The software

was used to predict noise contours associated with the operation of a proposed new range

and was then used to explore revisions to the range location and design to reduce the

noise level in the adjacent community. The primary performance measures were the

amount of noise dose reduction, the cost of use, and the projected cost savings.

11) SPM9613 Community Noise Prediction Software, Version 2

Born from our years of estimating and predicting noise from industrial noise

sources, Power Acoustics, Inc. has developed and optimized a low-cost computer

program for analyzing community noise and sound propagation emitted from a variety of

noise sources. The engineering software is based on the ISO 9613 parts 1 and 2

standards. SPM9613 provides calculations at specific field points (listeners) and

predictions of A- and C-weighted sound level contours as well. We sell this software as a

low cost alternative to more expensive and difficult to use computer programs.

The original release of our community noise sound propagation model,

SPM9613™ was in January 1999. Version 2 was released in February 2002. The

software has a Windows based user interface and enables users to perform multi-source

and distributed source predictions with barriers and reflective surfaces. Because the

software is developed by a company that is also an end user, it is extremely flexible and

easy to use.

SPM9613 Features and Extensions

• Fast setup and calculation times

• Automatic breakdown of large 3-D or line sources into multiple point sources

• Multiple barriers

• Reflections - automatic image sources

• Ground Attenuation with defined limits

• Miscellaneous Attenuation (Foliage, Industrial Sites)

• Graphical capability to assure correct user inputs

• Plan views of equipment, barriers, foliage or industrial sites, and observer

locations


60

• Source sound power level spectrum plots and directivity plots (vertical and

horizontal)

• Sorted sound source waterfall plots at each observer location

• Contour plotting of A or C weighted levels

• 3-D Ground Elevation plots

• Ground Hardness contours

• Extended Octave Band Center Frequency range - 16 to 8000 Hz

• Computation of C-weighted levels

• Source sorting on A or C-weighting

• Customizing services available

• MS Windows 95, 98, NT, 2000, XP, Vista and Windows 7 Compatible

All calculations, sound sources, barriers, ground elevations and observers are

represented internally within SPM9613 in three dimensions (x, y, z coordinates).

Graphical output is presented in plan views of the equipment and observers and with

contour plots.

There are many other factors which influence the accuracy and usefulness of

models in practice, including the following:

3.8.4 Other factors related to the ways in which models are used in practice

Absence of nationally standardised requirements for the verification and quality

assurance of commercial software which implement engineering methods, leading to a

very wide range of performance and suitability for purpose.

In the absence of clearly defined assessment requirements, the conditions that

should be included in prediction models are often selected in a somewhat arbitrary

manner. There is no defined system for generating traceable accounts of a model output’s

development/construction.

There is varied industry understanding of modelling limitations.

There is an absence of guidance on how to deal with the limitations and

uncertainties of predictions.


61

Noise modelling studies are generally constrained to fall short of the ideal, due to

budget restrictions.

Many environmental noise assessment projects are won through a competitive

tendering process, so bidders are often obliged to limit their scope to one which allows

for less rigorous investigations to be undertaken than the bidder would recommend under

less competitive circumstances, and those commissioning prediction studies

understandably seek the lowest cost options without necessarily understanding the

potential trade-off between decreasing study cost and increasing outcome uncertainty.

For example, the increased risk of consequential loss associated with increased

uncertainty is not always appreciated.

There may also be limited access to information: due either to limited resources to

collect information, or as often occurs, due to the confidentiality surrounding certain

information depending on the relationship between the practitioners, the party

commissioning the study, and the noise producer.

3.9 Worldwide Noise Allowable Limits

1) ADNOC (UAE) Environmental Noise Limits

ADNOC’s guidelines values are detailed in the following sections.

Table 4– ADNOC Noise Allowable Limits in Different Areas

AREA

Allowable Limits for Noise Levels (dB (A))

Day

(7 a.m. – 8 p.m.)

Night

(8 p.m. – 7 a.m.)

Residential areas with light traffic 40 – 50 30 – 40

Residential areas which include

some workshops & commercial

business or residential areas near a

highway

50 – 60 40 – 50

Commercial areas 55 – 65 45 – 55

Industrial areas (heavy industry) 60 – 70 50 – 60


62

2) CPCB- Environmental Noise Limits

Table 5– CPCB Noise Allowable Limits in Different Areas

AREA Code AREA

Allowable Limits for Noise

Levels (dB (A))

Day Night

(A) Industrial area 75 70

(B) Commercial area 65 55

(C) Residential area 55 45

(D) Silence Zone 50 40

Notes

1. Day time shall mean from 6.00 a.m. to 10.00 p.m.

2. Night time shall mean from 10.00 p.m. to 6.00 a.m.

3. Silence zone is an area comprising not less than 100 meters around hospitals,

educational institutions, courts, religious places or any other area which is declared

as such by the competent authority

4. Mixed categories of areas may be declared as one of the four above mentioned

categories by the competent authority.

12) 3) Environmental Protection Agency- Environmental Noise Limits

Table 6– EPA Noise Allowable Limits in Different Areas

Land use category


Day

(7 a.m. – 10 p.m.)

Night

(10 p.m. – 7 a.m.)

Rural Living 47 40

Residential 52 45

Rural Industry 57 50

Light Industry 57 50

Commercial 62 55

General Industrial 65 55

Special Industry 70 60


63

Chapter-4

CASE STUDY- NOISE MODELLING OF SOUTH ISLAND

USING SOUNDPLAN 7.2 SOFTWARE

4.1 Executive Summary

A noise study for ZADCO UZ750K Project, South Island EPC2 has been

undertaken. The assessment has been conducted in line with ADNOC recommended

environmental noise limit values[20]

, ADNOC HSE Management Codes of Practice [21]

,

ZADCO’s noise design requirements for plant [22]

and Project HSE Philosophy[23]

.

The aim of the study was to demonstrate that EPC2 package facilities will comply

with 85 dB (A) at 1 m during normal operations and 115 dB (A) during emergency

conditions. An assessment of the likely impact on nearby noise sensitive receptors has

also been conducted in accordance with ADNOC allowable noise limits [20]

.

A review of equipment lists, plot plans and vendor supplied data was carried out

to identify noise items of equipment and model them to determine the cumulative noise

impact across South Island. The significant noise generating sources of plant that include

pumps, compressors, generators, the nitrogen package and piping noise were modelled

using SoundPLAN v7.2.

Both normal and emergency operations were modelled and noise contour maps

produced. Sources were either modelled as a point or area sources. In total, 45 noise

sources were modelled. Piping and control valve noise was modelled as an area source

within EPC2 process plant area. At this stage control valve data is not yet finalised

therefore it was estimated control valve and piping noise would account for 10 % of the

total sound energy within the process area.

Current vendor information indicated EPC2 equipment would meet the work area

noise limit of 85 dB(A) at 1 m and the results of the noise modelling showed cumulative

noise levels within the process areas would fall to below 70 dB(A) at the battery

boundary. The worker accommodation is located approximately 200 m south west of the

EPC2 process plant, predicted noise contribution from EPC2 process plant at the


64

accommodation area was predicted to be below 50 dB(A) and was in accordance with the

allowable noise limit prescribed by ADNOC.

Emergency plant was limited to firewater pumps and the emergency generators

both of which were found to be in compliance with the emergency nose limit of 115

dB(A). The PA system shall be designed at a minimum of 6 dB higher than the maximum

background level as per the project specification.

The following recommendations are made:

This report shall be updated during the Phase 3 HSEIA on receipt of vendor

information on equipment noise levels, noise levels from piping, control valves and

pressure safety valves. This will ensure compliance of with the FEED HSEIA

recommendation E6.

Cumulative noise impact from all the three compressor trains (2215-B-

1002),operating simultaneously needs to be evaluated at a later stage, and the need for

additional noise controls such as isolation mounts, acoustic insulation, discharge and

suction line silencers, acoustic cladding etc., shall be assessed.

4.2 Background

DNV GL has been retained by ZADCO to conduct a Noise study for the South

Island (SI) EPC2 package located of ZADCO UZ750k Project.

This report presents the findings of the preliminary noise modelling assessment

for normal and emergency operations associated with the equipment designated under the

EPC2 package. Modeled operational plant noise levels have been compared directly with

ADNOC [20]

and ZADCO [23]

noise requirements.

4.3 Noisy Equipment

Following a review of the EPC2 package equipment list the items detailed in

Table 7 were considered potential noise sources to be included in the noise model. The

maximum expected sound pressure level shown in the table for each noise source is

according to equipment datasheet and ZADCO noise specification [22]

. Full details of

modeled equipment are detailed in Appendix A.


65

Table 7– EPC2 Potential Noise Sources

Equipment Tag Equipment Name

Maximum Expected

Sound Pressure Level

at 1 m (dBA)

2202-P-

1001A/B/C/D/E/F Crude Oil Transfer Pumps 85

2210-P-1002

A/B/C/D/E/F Produced Water Disposal Pumps 85

2215-B-1001 Air Compressor Package ( Three Trains) 85

2215-B-1002 Compressed Air Dryer Package ( Three

Trains) 85

2216-B-1001 Nitrogen Generation Package 85

2117-B-1-002 Electro chlorination Package 85

2217-P-1001A/B/C Service Water Winning Pumps 85

2217-P-1010 A/B Drilling Water Supply Pumps 85

2211-P-1001A/B MP Flare KO Pump 85

2214-P-1005A/B Drain Water Disposal Pumps 85

2214-P-1001A/B Storm Basin Pumps 85

2214-P-1003A/B Lift Station Pumps (Small) 85

2214-P-1004A/B Lift Station Pumps (Large) 85

2219-P-1001

A/B/C/D/E Fire Water Pump (Diesel Engine Driven) 105

2200-G-001 Emergency Diesel Generator 85

2200-B-002 Emergency Diesel Generator 85


66

4.4 Noise Standards

This section presents the national and international standards, guidance and

project specifications applicable to this assessment.

4.4.1 Noise Requirements

The control of noise for the Project is required for the following reasons:

Ensure compliance with Abu Dhabi National Oil Company (ADNOC)

environmental noise criteria

Conserve the hearing of personnel

Reduce speech and work interference

Ensure that warning signals are audible

Allow adequate speech, telephone and radio communication

Maintain working efficiency

4.4.2 Environment

4.4.3 ADNOC Environmental Noise Limits

The assessment has been conducted in line with ADNOC recommended

environmental noise limit values [20]

, ADNOC HSE Management Codes of Practice [21]

,

ZADCO’s noise design requirements for plant [22]

and Project HSE Philosophy [23]

.

ADNOC’s guidelines values are detailed in the following sections.

Table 8– ADNOC Noise Allowable Limits in Different Areas

AREA


Day

(7 a.m. – 8 p.m.)

Night

(8 p.m. – 7 a.m.)

Residential areas with light traffic 40 – 50 30 – 40

Residential areas which include some workshops &

commercial business or residential areas near a highway 50 – 60 40 – 50

Commercial areas 55 – 65 45 – 55

Industrial areas (heavy industry) 60 – 70 50 – 60


67

4.4.4 Project HSE Philosophy

The Project’s HSE Philosophy [21]

outlines the noise limits for plant areas for the

Project and is in accordance with ZADCO Corporate Noise Design Requirements [22]

.

4.4.5 Work Area Noise

The sound pressure level, superimposed on the existing background noise level, in

the work area within the new facilities shall not exceed 85 dB (A) at any point 1 m away

from any equipment surface.

4.4.6 Restricted Area Limit

Restricted areas are those work areas in the plant where it is not reasonably

practicable to reduce the noise level below the work area limit. Attempts shall be made to

reduce the level below 90 dB (A) for restricted areas and 95 dB (A) for very restricted

areas [23]

.

If it is unavoidable that the work area limit will be exceeded around particular

equipment, action shall be taken to reduce the area involved as much as feasible; this may

include the installation of an acoustical enclosure. It is accepted that areas inside

acoustical enclosures around such equipment are restricted areas.

4.4.7 Absolute Noise Level

The sound pressure level for broadband noise shall not exceed 115 dB(A) [21]

,

measured with an instrument set to slow response, at any time and at any place which is

accessible to personnel in any situation, including emergencies such as the blowing of

safety relief valves. The absolute limit does not apply inside of any vendor supplied

enclosure.

4.4.8 Work Area and Living Quarter Area Noise Limits.

Table 9and Table 10 present project noise level limits for inside buildings in order to

ensure effective communication, working and resting environment.


68

Table 9– Noise Limits for Specific Work Areas [23]

Area Description Maximum Allowable Sound

Pressure Level in dB (A)

Workshop 70

General store 70

Control rooms 55

Offices 55

Laboratories 55

Telecommunication room 55

Radio rooms 45

Table 10– Noise Limits Living Quarters [22]

Area Description Maximum Allowable Sound

Pressure Level in dB (A)

Washing facilities 60

Changing rooms 60

Toilets 60

Mess rooms 55

Recreation rooms 55

TV and film lounge 45

Sleeping quarters 45

Medical rooms 45

Library, quiet rooms 45

4.5 Summary of Design Project Noise Limits


69

Table 11Summarises the proposed design noise limits for EPC2 [22]

.

Table 11– Summary of Design Noise Limits

Criteria Maximum Allowable Sound

Pressure Level in (dB (A))

Worker Accommodation (External) 50

Work area noise limit at 1m 85

Absolute noise limit 115

Restricted Area Limit 90

Very Restricted Area Limit 95

4.6 International Guidance

4.6.1 International Organization for Standardisation (ISO) 1996-1-3 ‘Description

and Measurement of Environmental Noise’

ISO 1996-1-3 ‘Description and Measurement of Environmental Noise’ [24]

defines

the basic quantities to be used for the description of noise in community environments

and describes the basic procedures for the determination of these quantities. It also

describes the methods for acquisition of data that enable specific noise situations to be

checked for compliance with given noise limits.

4.6.2 International Organisation for Standardisation (ISO) 9613-2 ‘Acoustics –

Attenuation of Sound during Propagation Outdoors’

ISO 9613 Acoustics – Attenuation of Sound during Propagation Outdoors’ [25]

specifies an engineering method for calculating the attenuation of sound during

propagation outdoors in order to predict the levels of environmental noise at a distance

from a variety of sources. The method predicts the equivalent continuous A-weighted

sound pressure level (LAeq) under meteorological conditions favourable to propagation

from sources of known sound emission.


70

4.7 Modelling Methodology

4.7.1 Noise Model

In order to predict operational noise levels, the internationally recognised noise

modelling software, SoundPLAN, has been utilised.

A 3-dimensional model is produced by defining the relative/absolute heights of

the local ground surfaces, sources and any obstacles which may provide noise screening.

Noise screening calculations include effects from tanks, bunds and buildings. In the

absence of spectral data for plant, single figure barrier attenuations were used.

The propagation methodology adopted within the SoundPLAN model was the

International Organisation for Standardisation (ISO) 9613 ‘Acoustics – Attenuation of

Sound during Propagation Outdoors’ (ISO, 1996) [25]

.

ISO 9613 specifies an engineering method for calculating the attenuation of sound

during propagation outdoors in order to predict the levels of environmental noise at a

distance from a variety of sources. The method predicts the equivalent continuous A-

weighted sound pressure level (LAeq) under meteorological conditions favourable to

propagation from sources of known sound emission. The source (or sources) may be

moving or stationary and takes account of the following physical effects:

Geometrical divergence

Atmospheric absorption

Ground effect

Reflection from surfaces

Screening by obstacles

This method is applicable in practice to a great variety of noise sources and

environments. It is applicable, directly or indirectly, to most situations concerning:

industrial noise sources, road or rail traffic, construction activities, and many other

ground-based noise sources.


71

4.7.2 Propagation of Sound

Historically, the variables which affect sound propagation over ground away from

a source have been the subject of much detailed investigation over the years. The

principal factors influencing sound attenuation with distance from the source are:

Geometrical spreading (this is the standard spherical wave divergence term which

gives 6 dB reduction in noise level for each doubling of distance from a point source e.g.

small motor, and 3 dB for a line source e.g. piping[26]

Source directivity

Atmospheric (molecular) absorption

Ground effects (different for hard/soft ground, and type of ground cover)

Atmospheric wind temperature gradients (refraction)

Source height

Atmospheric turbulence

Barrier effects (Diffraction)

The total attenuation due to all these factors except geometrical spreading and

directivity is generally referred to as ‘excess attenuation’, and will vary with frequency.

Because of these effects, a significant noise source may not be significant at, and beyond,

the boundary and vice-versa. A noise source dominated by low frequency noise (with a

long wave length) is likely to travel a greater distance under the same excess attenuation

factors to that of a noise source dominated with high frequency noise (with a shorter

wavelength).

4.7.3 Meteorological and Ground Conditions

The most influential environmental condition on noise propagation is distance, the

greater the distance between the noise source and the receiver the greater the noise

reduction achieved. Typically for stationary sources (such as a refinery), a reduction of 6

dB (A) per doubling of distance is considered the norm [26]

The type of ground cover also influences noise propagation. Soft ground such as

sand or agricultural land absorbs sound energy shortening the propagation path whereas

hard ground such as compact soil or tarmac reflects the sound energy and thereby noise


72

travels further. It has been assumed for this assessment that the ground cover will be

hard standing.

For noise propagation over short distances climatic conditions do not have a

significant effect, however over longer distance over 50 m wind becomes more

influential. Downwind the level may increase by a few dB, depending on wind speed

whereas on the upwind or side-wind the level can drop by 10 dB.

Temperature gradients create effects similar to those of wind gradients, except

that they are uniform in all directions from the source. On a sunny day with no wind,

temperature decreases with altitude, giving a noise shadow. (The result is the noise is

taken up and away from the source and the ground). On a clear night temperature may

increase with altitude (temperature inversion) focusing sound towards the ground surface.

Table 12 summarises the climatic conditions experienced at South Island Project

site [27]

.

Table 12 – South Island Climatic Conditions

Parameter Value

Temperature Summer maximum 45

oC

Winter minimum 28 oC

Wind Direction Prevailing North West

Humidity Maximum 90%

Minimum 50%

Metrological conditions are unlikely to have a significant effect on the

transmission/attenuation of noise across the island due to the relatively small size of the

island. However, for the purposes of the noise assessment and in keeping with a

conservative approach, values were selected which applies reasonably worst-case

conditions for noise propagation i.e., the least amount of climatic attenuation over the

modelling domain. ISO 9613 assumes moderate wind speed in all directions, which is

considered a reasonable worst case.


73

4.7.4 Modelled Equipment

Equipment was either modelled as a point or area source. The compressor trains,

pumps, nitrogen package and emergency generators were modelled as point sources and

the pipe racks were modelled as area sources. Lw values were estimated using the

following general acoustic equations, where r = 1metre:

Lw = Lp + 20 log10 (r) + 8dB (semi-spherical point source)

Lw = Lp + 20 log10 (r) + 11dB (spherical point source)

The estimated values are presented in Appendix A.

Data on control valves is not yet finalised, however vendors will need to design

control valves to comply with 85 dB (A) noise limit at 1 meter. In order to represent noise

from control valves and associated piping within the model, a conservative estimate has

been made that piping noise will account for 10% of the total sound power level per unit

area.

The sum sound power level of all equipment within the project was calculated at

107 dB (A) therefore piping noise was calculated at 97 dB (A). Please note that the

piping noise is isolated to pipe racks located in EPC2 Process area.

Noise from control valves will be re-assessed when this data is available.

4.7.5 Modelling Basis and Assumptions

The following assumptions have been made for the modelling assessment, and

wherever possible, a conservative approach has been taken:

Noise sources have been modelled as either point or area sources.

Pipe and control valve noise has been modelled as 10% of the total sound power level

of all other equipment.

There are no noise barriers between source and receptors, unless specified.

Calculations have been performed in the eight octave bands centered between 63

hertz (Hz) and 8 kilo hertz (kHz).

The model does not incorporate features which might provide partial screening (e.g.,

columns, pipe racks, structural steelwork, and small equipment) but does include

tanks and buildings.


74

Ground absorption has been modelled conservatively as hard (having an absorption

coefficient of 0).

The topography between noise source and the site boundary receptors is flat (in

reality, the topography may undulate leading to attenuation of noise).

Reasonable worst case meteorological conditions have been applied, i.e. steady wind

conditions blowing in each direction.

It is assumed that predicted noise level due to the project is more than 10dB (A)

higher than the background noise level. ADNOC Manual of Codes of Practice

Guideline on OHRM: Noise Control and Hearing Conservation, ADNOC CoP V3-10,

2009 in above table depicts that with a difference of 10dB noise level addition to a

higher noise level is 0.4 dB which is negligible. Therefore no background noise data

has been included in this model.

4.8 Predicted Noise Levels

Three noise contour maps have been prepared to determine the noise levels in-

plant areas, across the facility, and beyond the battery unit at ground level. Calculations

have been carried out under normal operating and emergency conditions to determine

level of compliance to environmental, occupational and project specific noise

requirements. Noise contour maps of the outputs are presented in Appendix B as follows:

Figure B1: EPC2 Normal Operations PBU 1 Phase: Noise Contour

Figure B2: EPC2 Normal Operations PBU 2A Phase: Noise Contour

Figure B3: EPC2 Emergency Conditions : Noise Contour

4.8.1 Normal Operations

EPC2 will include two operational phases; PBU 1 and PBU 2A. Along with the

noisy equipment modelled in PBU 1,

- PBU 2A also includes the following equipment items:

2202-P1001A F Crude Oil Transfer Pumps

2210-P-1002A-F Produced Water Disposal Pumps

High noise levels are localised to individual items of equipment within EPC2 with

cumulative noise levels falling to below 70 dB (A) at the battery fence line.


75

The nearest noise sensitive receptors (NSRs) in the immediate vicinity of EPC2

area are the Camp and other administration buildings located approximately 200m to the

south west. As per the ANDOC allowable noise limits the camp and future permanent

accommodation area shall be classified as a residential area which includes some

workshops. Night time noise limits for such areas are 40-50 dB (A). Figure B1 and B2

shows that EPC2 noise contribution at the accommodation area is estimated to be below

50 dB (A) and therefore comply with the ADNOC limits.

Process buildings that are expected to be manned have also been included in the

study to predict external noise levels, although these buildings are not considered

sensitive from an environmental perspective. The maximum predicted noise levels at the

NSRs and process buildings are listed in and are presented in Appendix B, Figure B-2 for

PBU 1 and Figure B-3 for PBU 2a.

Table 13– Maximum Predicted Noise Levels at Selected Receptors

Receptor Description

PBU 1 Predicted

External Noise

Level (dB(A))

PBU 2a Predicted

External Noise

Level (dB(A))

R1 Accommodation Boundary

(NSR) 50 53

R2 Local Control Room 55 58

R3 Main Substation 58 60

R4 MTR 68 73

R5 Local Equipment Room 1 53 55

R6 Local Equipment Room 2 53 55


76

Noise inside process and non-process buildings is specified and ensured by

Heating Ventilation and Air Conditioning (HVAC) Philosophy and specification. For

accommodation, this shall be part of AUP contractor scope for the buildings.

External noise levels of the buildings have been defined in Table 12. It is expect

that approximately 25-30 dB (A) of noise level reduction shall be achieved for these blast

and fire resistant buildings based on data presented in Table 14. Considering the

maximum external noise levels of 73 dB (A) for normal operations, the internal noise

limit can be met due to the attenuation.

External noise attenuation by building walls, and control of the internal HVAC

noise as specified within the HVAC philosophy and specification shall ensure

compliance with COMPANY Noise Design requirements.

Table 14– Sound Insulation of Typical Windows

Description Weight Sound Reduction Rw, dB

Any type of window in a façade when partially open 10 +/- 15

Single glazed windows (4 mm glass) 22 +/- 30

Thermal insulating units (6-12-6) 33 +/- 35

Secondary glazed windows (6-100-6) 35 +/- 40

Secondary glazed windows (4-200-4) 40 /- 45

4.8.2 Emergency Operations

The emergency noise contour map shows high noise levels around the firewater

pumps to the south of the island and to a lesser extent around the emergency generators to

the northwest. The PA system shall be designed at a minimum of 6 dB higher than the

maximum background level as per the project specification. The model does not currently

include noise from PSVs associated with EPC2 process plant; however PSV noise shall

be for a short duration and have a limited impact on the daily exposure level to workers.

PSVs will be included in the next noise model. Presently, noise generated in the piping

during emergency is covered by considering 10 dB (A) additional piping noise as a


77

thumb rule. Noise modelling and assessment due to operation of blow down valves

considering vendor input shall be undertaken in the HSEIA Phase 3.

4.8.3 Control and Safety Valves

Currently there is not enough project data to include individual control or pressure

safety valves in the model. However piping noise has been included in EPC2 process

area, which provides a level of expected noise allocation from valve noise

Control valves that operate continuously or intermediately will need to comply

with the work area noise limit of 85 dB (A) at 1m. Whereas pressure safety valves or

control valves discharging in upset conditions should be designed not to exceed 115 dB

(A) at 1 m. The design of the PA system should therefore take these two parameters into

consideration.

Where there is the potential for control valves to exceed 85 dB (A), noise control

measures shown in Appendix C should be considered as a means of noise control.


78

Chapter 5.

RESULTS AND DISCUSSION

The aim of this study is to demonstrate that EPC2 package facilities will comply

with ADNOC [20]

and ZADCO’s noise requirements and design specifications [21]

. This

study is based on preliminary design data.

The significant noise generating sources of plant that include pumps,

compressors, generators, the nitrogen package and piping noise were modelled using

SoundPLAN v7.2. Normal and emergency operations were modelled and noise contour

maps produced for each. Sources were either modelled as a point or area sources. In total,

45 noise sources were modelled.

At this stage equipment noise data and specifications are limited, but it has been

confirmed that individual equipment items would meet the work area noise limit of 85 dB

(A) at 1 m. The exception to this was the firewater pumps that were modelled at 105 dB

(A) at 1 m and the emergency generators that were modelled at 85 dB (A) at 1m.

The modelling results show that the noise Levels across EPC2 process area range

from 62-85 dB (A) and that equipment would be in compliance with the work area noise

limits.

The emergency conditions scenario included all EPC2 equipment as well as the

firewater pumps and emergency generators. It is considered unlikely that noise from the

fire water pumps and generators will have a significant impact on the design of the PA

system and will not exceed the absolute noise level of 115 dB(A).

It is expected that equipment vendors will achieve the project noise limit of 85 dB

(A) at 1 m, if this is the case then it is predicted that EPC2 should be compliant with the

Project noise standards.

It should however be noted that as there are three compressor trains, these

cumulatively could pose a potential exceedance in the work area noise limit of 85 dB (A).

Therefore careful consideration should be made to the suction and discharge lines and

compressor connection points. Possible noise control measures include; isolation mounts,

acoustic insulation, silencers and acoustic cladding.


79

The following recommendations are made:

• This report shall be updated during the Phase 3 HSEIA on receipt of vendor

information on equipment noise levels, noise levels from piping, control valves

and pressure safety valves. This will ensure compliance of with the FEED HSEIA

recommendation E6.

• Cumulative noise impact from all the three compressor trains (2215-B-1002)

operating simultaneously needs to be evaluated at a later stage, and the need for

additional noise controls such as isolation mounts, acoustic insulation, discharge

and suction line silencers, acoustic cladding etc., shall be assessed.

• Noise Verification Survey during commissioning and normal operation of the

plant should be carried out per ZADCO requirement.


80

Noise Data Log

Table 15– EPC2 Process Plant Equipment Data Log Book


Number

of

sources

Height

above

ground

(m)

Continuous/

Intermittent /

Emergency

Scenario

Modelled

Source

Type

Equipment

Specification

Noise Limit

at 1 m

(dBA)

Sound

Power

Level

(dB)

Sound Power level frequency spectrum (dB)

63

Hz

125

Hz

250

Hz

500

Hz

1

KHz

2

KHz

4

KHz

8

KHz

2202-P-

1001A/B/C/D/E/F

Crude Oil Transfer

Pumps 6 1 C

PBU 2A/

Emergency Point 85 96 84.8 85.8 87.8 87.8 90.8 87.8 83.8 77.8

2210-P-1002

A/B/C/D/E/F

Produced Water

Disposal Pumps 6 1 C

PBU 2A/

Emergency Point 85 96 84.8 85.8 87.8 87.8 90.8 87.8 83.8 77.8

2215-B-1001 Air Compressor

Package 3 2.5 C

PBU 1 /

PBU 2A/

Emergency

Point 85 96 81.6 86.6 85.6 83.6 86.6 91.6 88.6 81.6

2215-B-1001

Air Compressor

Package (Air

coolers)

3 9.5 C

PBU 1 /

PBU 2A/

Emergency

Point 85 96 81.6 86.6 85.6 83.6 86.6 91.6 88.6 81.6

2215-B-1002

Compressed Air

Dryer Package

(Three Trains)

1 2.5 C

PBU 1 /

PBU 2A/

Emergency

Point 85 96 81.6 86.6 85.6 83.6 86.6 91.6 88.6 81.6

2216-B-1001

Nitrogen

Generation

Package

1 9.5 C

PBU 1 /

PBU 2A/

Emergency

Point 85 96 81.6 86.6 85.6 83.6 86.6 91.6 88.6 81.6

2117-B-1-002

Electro

chlorination

Package

1 1 C

PBU 1 /

PBU 2A/

Emergency

Point 85 96 81.6 86.6 85.6 83.6 86.6 91.6 88.6 81.6


81


Number

of

sources

Height

above

ground

(m)

Continuous/

Intermittent /

Emergency

Scenario

Modelled

Source

Type

Equipment

Specification

Noise Limit

at 1 m

(dBA)

Sound

Power

Level

(dB)


63

Hz

125

Hz

250

Hz

500

Hz

1

KHz

2

KHz

4

KHz

8

KHz

2217-P-

1001A/B/C

Service Water

Winning Pumps 3 1 C

PBU 1 /

PBU 2A/

Emergency

Point 85 96 84.8 85.8 87.8 87.8 90.8 87.8 83.8 77.8

2217-P-1010 A/B Drilling Water

Supply Pumps 2 1 C

PBU 1 /

PBU 2A/

Emergency

Point 85 96 84.8 85.8 87.8 87.8 90.8 87.8 83.8 77.8

2211-P-1001A/B MP Flare KO

Pump 2 1 E

PBU 1 /

PBU 2A/

Emergency

Point 85 96 84.8 85.8 87.8 87.8 90.8 87.8 83.8 77.8

2214-P-1005A/B Drain Water

Disposal Pumps 2 1 C

PBU 1 /

PBU 2A/

Emergency

Point 85 96 84.8 85.8 87.8 87.8 90.8 87.8 83.8 77.8

2214-P-1001A/B Storm Basin

Pumps 2 1 I

PBU 1 /

PBU 2A/

Emergency

Point 85 96 84.8 85.8 87.8 87.8 90.8 87.8 83.8 77.8

2214-P-1003A/B Lift Station Pumps

(Small) 2 1 C

PBU 1 /

PBU 2A/

Emergency

Point 85 96 84.8 85.8 87.8 87.8 90.8 87.8 83.8 77.8

2214-P-1004A/B Lift Station Pumps

(Large) 2 1 C

PBU 1 /

PBU 2A/

Emergency

Point 85 96 84.8 85.8 87.8 87.8 90.8 87.8 83.8 77.8


82


Number

of

sources

Height

above

ground

(m)

Continuous/

Intermittent /

Emergency

Scenario

Modelled

Source

Type

Equipment

Specification

Noise Limit

at 1 m

(dBA)

Sound

Power

Level

(dB)


63

Hz

125

Hz

250

Hz

500

Hz

1

KHz

2

KHz

4

KHz

8

KHz

2219-P-1001

A/B/C/D/E

Fire Water Pump

(Diesel Engine

Driven)

5 1 E Emergency Point 105 116 101.8 102.8 104.8 104.8 107.8 104.8 100.8 94.8

2200-G-001 Emergency Diesel

Generator 1 2 E Emergency Point 85 96 89.9 90.9 90.9 90.9 88.9 86.9 83.9 78,9

2200-B-002 Emergency Diesel

Generator 1 2 E Emergency Point 85 96 89.9 90.9 90.9 90.9 88.9 86.9 83.9 78,9

- Process Piping 2 10 C

PBU 1 /

PBU 2A /

Emergency

Area - 97 - - - - - - - -


83

Noise Contour Maps

Figure 6:– EPC2 Normal Operations PBU 1 Phase Noise Contour

R1

R2

R3

R4

R5

R6


84

Figure 7:– EPC2 Normal Operations PUB 2A Phase Noise Contour

R1

R2

R3

R4

R5

R6


85

Figure 8:– EPC2 Emergency Conditions Noise Contour


86

5.1 Recommended Noise Controls for Valves and Piping Where

Applicable

5.1.1 Low Noise Valves

Low-noise’ trims for valves are commonly specified as a means of noise control

to meet workplace noise limits. These ‘low-noise’ trims reduce the pressure in numerous

discrete stages within the valve, resulting in lower valve-generated noise levels Figure A3

shows one arrangement of a ‘low noise’ valve (for example).

Figure 9– Low Noise Valve with Whisper Trim Type Cage

5.1.2 Multi Stage Restriction Orifices

As with ‘low noise’ valves, ‘low noise’ multi-stage restriction orifices, consisting

of a number of pressure-reducing plates or perforated screens, are available. Each plate,

or stage, is larger than the previous one, to adjust for increases in fluid volume as the

pressure is decreased. Figure A4 presents a typical arrangement of a multi-stage

restriction orifice.


87

Figure 10– Multi Stage Restriction Orifice

5.1.3 In-Line Silencers

In-line silencers are the most effective path treatment for attenuating acoustic

energy. A silencer located in the line downstream of a pressure reducing valve will

reduce the acoustic energy near its point of origin and prevent it from propagating along

the pipe.

5.1.4 Piping Insulation

International Organisation Standards (ISO) document: 15665; Acoustics-

Acoustic insulation for pipes, valves and flanges [28]

. This standard defines the three

classes of acoustic insulation, namely, A, B and C. The insertion loss data for each class

of acoustic insulation is detailed in Table A2.

The insertion loss of acoustic insulation is related to the diameter of the pipe on

which it is applied. The pipe diameters are divided into three pipe size groups and the

insulation class will consist of a letter/number combination indicating the diameter on

which the insulation is applied.


88

Table 16– Minimum Insertion Loss Required for each Acoustic Insulation Class

Class

Range Pipe

Diameter (D)

(mm)

Minimum Insertion Loss, dB

centre octave band frequency

Overall Insertion Loss

dB(A) (Note 1)

125 250 500 1K 2K 4K 8K PSV CV Compressor

A1 D < 300 -4 -4 2 9 16 22 29 22 14 10

A2 300 ≤ D < 650 -4 -4 2 9 16 22 29 22 14 10

A3 650 ≤ D <1000 -4 2 7 13 19 24 30 23 18 15

B1 D < 300 -9 -3 3 11 19 27 35 27 16 11

B2 300 ≤ D < 650 -9 -3 6 15 24 33 42 34 18 14

B3 650 ≤ D <1000 -7 2 11 20 29 36 42 35 22 18

C1 D < 300 -5 -1 11 23 34 38 42 36 22 18

C2 300 ≤ D < 650 -7 4 14 24 34 38 42 36 24 20

C3 650 ≤ D <1000 1 9 17 26 34 38 42 36 29 25

Note 1: The overall insertion loss is for guideline purposes only and is based on ISO 15665 procedures. The

variation in the effectiveness of the insulation type between equipment items is due to the difference in

sound energy distribution between the frequency octave bands. For example PSVs are dominated by high

frequency acoustic energy and therefore the insertion loss is greater than for that of compressors where the

sound energy is distributed more evenly in the mid-range frequencies.


89

CONCLUSIONS AND RECOMMENDATIONS

The computational results estimated by SoundPLAN software indicate that the

placement of individual barriers around some of the noisier equipment’s/machines did

not suffice to limit the noise propagating to the external environment. Since the main

objective is to control the cumulative noise propagating to the external environment, the

partial placement of barriers along some critically noisy walls or additional noise controls

such as isolation mounts, acoustic insulation, discharge and suction line silencers,

acoustic cladding etc. are more effective to control nighttime noise, preventing the

emission. limit of 50 dB(A) from reaching the neighborhood and adjacent buildings in the

factory.

The use of this Environment methodology allows one to predict noise distribution

patterns in the proximities of manufacturing plants, aiming to devise measures to control

and reduce noise propagation and thereby satisfy any statutory body

(ADNOC/CPCB/EPA etc.) Noise Allowable Limits.

The use of computational tools to analyze noise is suitable for cases in which it is

important to be aware of the environmental impact produced by a plant in a given region.

The proposed methodology for predicting noise pollution prior to the construction,

expansion or modification of manufacturing units is useful, enabling one to meet current

noise regulations.


90

REFERENCES

1) The International Journal of Transport & Logistics Medzinárodný Časopis Doprava

A Logistika, Traffic Noise In Small Urban Areas, M. Hadzi-Nikolova, D.

Mirakovski , Z. Despodov , N. Doneva (Faculty of Natural and Technical Science

Stip, Macedonia, University)[2012]

2) Modeling and Mapping of Urban Noise Pollution with Soundplan Software, Ass.

Hadzi-Nikolova M, Ass. Prof. Mirakovski D, Ass. Ristova E, Ass. Ceravolo S. Lj,

(Faculty of Natural and Technical Science Stip, Macedonia, University) [2010]

3) Acoustics 2008, Geelong Victoria, Australia 24th

to 26th

November 2008,

Comparison of Kilde Report 130 Rail Noise Modelling Predictions for SoundPLAN

4.2 and 6.5, Mark Batstone, Rhys Brown and Jennifer Uhr [2008]

4) Rapport AMM 2011:2, Generalizations and Accuracy in Community Noise

Modelling – A Case Study on Railway Noise in Burlöv Municipality, Kristoffer

Mattisson [2011]

5) Proceedings of 20th International Congress on Acoustics, ICA 2010 23-27 August

2010, Sydney, Australia, Further Comparison of Traffic Noise Predictions Using the

CadnaA and SoundPLAN Noise Prediction Models, Peter Karantonis , Tracy Gowen

and Mathew Simon, Renzo Tonin & Associates (NSW) Pty Ltd, NSW, Australia

[2010]

6) Road Traffic Noise: GIS Tools for Noise Mapping and a Case Study for Skåne

Region, F. Farcaş , Å. Sivertun, Linköping University, Sweden

7) Acoustics 2008, Geelong Victoria, Australia 24th

to 26th

November 2008,

Comparison of Traffic Noise Predictions of Arterial Roads using Cadna-A and

SoundPLAN Noise Prediction Models Michael Chung , Peter Karantonis , David

Gonzaga and Tristan Robertson, Environmental Acoustics Team, Renzo Tonin &

Associates Pty Ltd, Australia [2008]

8) Modeling and simulation of noise impact along a new railway section in Sao Paulo,

Brazil Maria Luiza Belderrain, Rafael Vaidotas and Wanderley Montemurro, CLB

Engenharia Consultiva

9) Proceedings of MUCEET2009, Malaysian Technical Universities Conference on

Engineering and Technology June 20-22, 2009, MS Garden,Kuantan, Pahang,


91

Malaysia, MUCEET2009, A study on noise level produced by road traffic in

putrajaya using soundplan road traffic noise software, Abdullah, M.E., Shamsudin,

M.K., Karim, N., Bahrudin, I.A., and Shah, S.M.R

10) Traffic Noise Predictive Models Comparison with Experimental Data, Claudio

Guarnaccia*, Tony LL Lenza°, Nikos E. Mastorakis, and Joseph Quartieri**

Department of Physics “E.R. Caianiello”, Faculty of Engineering° Department of

Industrial Engineering, Faculty of Engineering University of Salerno

11) Using Traffic Models as a Tool When Creating Noise Maps- -Methods used in the

EU-project QCity Pia Sundbergh, Research Engineer Royal Institute of Technology

(KTH) Stockholm, Sweden

12) International Journal of Occupational Safety and Ergonomics (JOSE) 2011, Vol. 17,

No. 3, 309–325, 12), Problems of Railway Noise—A Case Study Małgorzata

Szwarc, Bożena Kostek, Józef Kotus, Maciej Szczodrak, Andrzej Czyżewski,

Faculty of Electronics, Gdańsk University of Technology, Gdańsk, Poland

13) Latest Trends in Energy, Environment and Development, Industrial Settlements

Acoustic Noise Impact Study by Predictive Software and Computational Approach

Claudio Guarnaccia*, Joseph Quartieri*, Alessandro Ruggiero*, Tony L. Lenza,

Department of Industrial Engineering, University of Salerno [2014]

14) Noise Dispersion Modelling in Small Urban Areas with CUSTIC 3.2 Software,

Marija Hadzi-Nikolova, Dejan Mirakovski, Todor Delipetrov, Pance Arsov, Faculty

of Natural and Technical Sciences, University “Goce Delcev” Stip, Macedonia

15) Integrating a Noise Modeling Capability With Simulation Environments, Raymond

M. C. Miraflor , NASA Ames Research Center, Moffett Field, California U.S.A

16) Integrated Noise Model Route Optimization for Aircraft, Student team: Jessica

Kreshover, Phil Larson, Simmons Lough, Eric Merkt, Faculty Advisors: Garrick

Louis and Christina Mastrangelo, Department of Systems Engineering

17) Noise mapping as a tool for controlling industrial noise pollution, W J P Casas1*, E

P Cordeiro1, T C Mello and P H T Zannin Universidade Federal do Rio Grande do

Sul, Departamento de Engenharia Mecânica, Rua Sarmento Leite


92

18) Modeling and Mapping of Urban Noise Pollution with SoundPLAN Software,

Marjia Hazdi-Nikoloava, Dejan Mirakovski, Emilija Ristova, Ljubica Stefanovska

Ceravolo

19) Guide to Predictive Modelling for Environmental Noise

20) ADNOC Manual of Codes of Practice: ‘Code of Practice on Environmental Impact

Assessment’, ADNOC-COP V2-01. (May 2004).

21) ADNOC HSE Management Codes of Practice Volume 3: Occupational Health,

Guideline on OHRM: Noise Control and Hearing Conservation.

22) ZADCO Corporate Engineering Specifications – Noise Design Requirements for

Plant and Equipment Z0-TS-M-01020

23) Project HSE Philosophy Upper Zakum 750 Islands Surface Facilities Project – EPC2

Project. P7512-BD-2000-N-0001. (04 July 2013).

24) International Organization for Standardisation (ISO) ISO1996-1-3 ‘Description and

Measurement of Environmental Noise’

25) International Organisation for Standardisation (ISO) ISO9613-2 ‘Acoustics –

Attenuation of Sound During Propagation Outdoors’.

26) Sharland, Ian. Woods Practical Guide to Noise Control. Woods of Colchester

Limited (1979).

27) Upper Zakum - 750K Artificial Islands Project, Environmental Scoping Report –

EPC 1&2, Vectra, 2011.

28) International Organisation for Standardisation (ISO) ISO15665 – ‘Acoustic

Insulation for Pipes, Valves and Flanges’

29) PA/GA System Specification - Green & Brown Field Upper Zakum 750 Islands

Surface Facilities Project – EPC2 Project., Doc No. P7512-TS-2000-T-0007, 2013

30) Table 10, BS 8233:1999, Sound insulation and noise reduction for buildings. Code

of practice.

31) K E Gilbert, M J White, “Application of the parabolic equation to sound propagation

in a refracting. atmosphere”, J. A. S. A. 85, pp.630-637, 1989. Details of the BEM

are given in S N Chandler-Wilde, “The boundary element method in outdoor noise

propagation”, Proceedings of the Institute of Acoustics 19(8), 27-50, 1997


93

Standards, regulations and guidance notes

• ISO 9613-2, Acoustics — Attenuation of sound during propagation outdoors —

Part 2: General method of calculation

• ADNOC Manual of Codes of Practice: ‘Code of Practice on Environmental

Impact Assessment’, ADNOC-COP V2-01. (May 2004).

• ADNOC HSE Management Codes of Practice Volume 3: Occupational Health,

Guideline on OHRM: Noise Control and Hearing Conservation.

• BS 4142, Method for rating industrial noise affecting mixed residential and

industrial areas

• BS 5228-2, Noise and vibration control on construction and open sites — Part 2:

Guide to noise and vibration control legislation for construction and demolition

including road construction and maintenance

• BS 7445, Description and measurement of environmental noise

• IPPC H3 Horizontal Noise Guidance. Part 1 ‘Regulation and Permitting’ and Part

2 'Noise Assessment and Control'

• Calculation of Road Traffic Noise 1988, Department of Transport, Welsh Office

• Calculation of Railway Noise 1995. Department of Transport

• The CAA Aircraft Noise Contour Model: ANCON Version 1. DORA Report

9120, Civil Aviation Authority 1992

• PPG 24 Planning Policy Guidance: Planning and Noise. Department of the

Environment 1994. TAN11 (Wales); PAN56 (Scotland)

• BS 9142: 2006 Assessment methods for environmental noise — Guide,

2003/01534 12 July 2006


iv

ABSTRACT

The Environmental Noise Modeling Using SoundPLAN 7.2 Software thesis has

been prepared for all parties who commission, undertake or use environmental noise

predictions for commercial or industrial operations, of whatever type or scale, for which

an environmental noise assessment may be required.

The purpose of this thesis is to identify the contribution of noise from external

sources to the noise pollution generated by a industry, by comparing sound pressure

levels measured in its surroundings and those calculated by noise mapping.

As an example ZADCO UZ750K Project, South Island EPC2 was chosen and

sound pressure levels were measured at discrete points along two rings around it, called

receivers.

The noise measurement data from the first ring were entered into the SoundPLAN

software to determine, through iteration, the South Island EPC2 main noise sources. The

software then used this information to calculate noise maps and sound pressure levels at

the receiver’s positions in the second ring. Finally, the contribution of noise from external

sources to the overall noise generated by the factory was determined by comparing the

noise measured in the second ring with the simulated data. The placement of partial

barriers along some critically noisy walls was found to be effective in controlling

nighttime noise, ensuring that the sound level limit for this type of neighborhood, which

is established by technical standards for environmental noise as Leq = 60 dB (A), is not

reached.


v

CONTENTS

SR.

NO. TITLE

PAGE

NO.

TITLE i

CERTIFICATE ii

ACKNOWLEDGEMENT iii

ABSTRACT iv

CONTENTS v

LIST OF FIGURES vii

LIST OF TABLES vii

1. INTRODUCTION 1

1.1 Why Environmental Noise Modelling 2

1.2 Environmental Noise Modelling 3

1.3 Uses of the Environmental Noise Modelling: 5

1.4 Information Needed to Construct a Noise Model 6

1.5 Models in general use and their intrinsic limitations and risks 9

1.5.1 Practical Engineering Methods: 9

1.5.2 Approximate Semi-Analytical Methods: 9

1.5.3 Numerical Methods: 10

1.5.4 Hybrid Models: 12

1.5.5 Ray-Tracing Models 12

1.6 Reliability of the Environmental Noise Modelling 14

2. LITERATURE REVIEW 15

3. ENVIRONMENTAL NOISE MODELLING METHODOLOGY 25

3.1 Stage 1: Review the Requirement for Predictions 26

3.2 Stage 2: Preliminary Screening Study 26

3.3 Stage 3: Detailed Model Design 27

3.3.1 Physical Environment 28

3.3.2 Sources 29

3.3.3 Propagation Algorithm 30


vi

3.4 Stage 4: Execute Calculations 31

3.5 Stage 5: Analyse and Report 31

3.6 Risks in Environmental Noise Assessment 32

3.6.1 Introduction 32

3.7 Risk, Variability and Uncertainty 34

3.8 Factors Affecting Risk in Environmental Noise Predictions 38

3.8.1 Input Data 39

3.8.2 Algorithms for Outdoor Sound Propagation 41

3.8.3 Environmental Noise Modelling Proprietary Software 41

3.8.4 Other factors related to the ways in which models are used in

practice

58

3.9 Worldwide Noise Allowable Limits 59

4. CASE STUDY- NOISE MODELLING OF SOUTH ISLAND

USING SOUNDPLAN 7.2 SOFTWARE

61

4.1 Executive Summary 61

4.2 Background 62

4.3 Noisy Equipment 62

4.4 Noise Standards 64

4.4.1 Noise Requirements 64

4.4.2 Environment 64

4.4.3 ADNOC Environmental Noise Limits 64

4.4.4 Project HSE Philosophy 65

4.4.5 Work Area Noise 65

4.4.6 Restricted Area Limit 65

4.4.7 Absolute Noise Level 65

4.4.8 Work Area and Living Quarter Area Noise Limits. 65

4.5 Summary of Design Project Noise Limits 66

4.6 International Guidance 67

4.6.1 International Organization for Standardisation (ISO) 1996-1-

3 ‘Description and Measurement of Environmental Noise’

67


vii

4.6.2 International Organisation for Standardisation (ISO) 9613-2

‘Acoustics – Attenuation of Sound during Propagation Outdoors’

67

4.7 Modelling Methodology 68

4.7.1 Noise Model 68

4.7.2 Propagation of Sound 69

4.7.3 Meteorological and Ground Conditions 69

4.7.4 Modelled Equipment 71

4.7.5 Modelling Basis and Assumptions 71

4.8 Predicted Noise Levels 72

4.8.1 Normal Operations 72

4.8.2 Emergency Operations 74

4.8.3 Control and Safety Valves 75

5. RESULTS AND DISCUSSION 76

5.1 Recommended Noise Controls for Valves and Piping Where

Applicable

84

5.1.1 Low Noise Valves 84

5.1.2 Multi Stage Restriction Orifices 84

5.1.3 In-Line Silencers 85

5.1.4 Piping Insulation 85

CONCLUSIONS AND RECOMMENDATIONS 87

REFERENCES 88


viii

LIST OF FIGURES

FIGURE

NO. TITLE

PAGE

NO.

1 The simplest type of model 4

2 Noise Contours 4

3 Common approach to environmental noise measurements 25

4 Indicative sound level versus distance chart depicting increasing

variability with distance from source

37

5 Industrial Noise Indoors and outdoors with Noise Transmission 43

6 EPC2 Normal Operations PBU 1 Phase Noise Contour 81

7 EPC2 Normal Operations PUB 2A Phase Noise Contour 82

8 EPC2 Emergency Conditions Noise Contour 83

9 Noise Valve with Whisper Trim Type Cage 84

10 Multi Stage Restriction Orifice 85


ix

LIST OF TABLES

TABLE

NO. TITLE

PAGE

NO.

1 Necessities of the specification of a noisy environment 7

2 Features of commonly used environmental noise modelling

methods

13

3 Significant causes of variation in environmental noise sound fields 35

4 ADNOC Noise Allowable Limits in Different Areas 59

5 CPCB Noise Allowable Limits in Different Areas 60

6 EPA Noise Allowable Limits in Different Areas 60

7 EPC2 Potential Noise Sources 63

8 ADNOC Noise Allowable Limits in Different Areas 64

9 Noise Limits for Specific Work Areas 66

10 Noise Limits Living Quarters 66

11 Summary of Design Noise Limits 67

12 South Island Climatic Conditions 70

13 Maximum Predicted Noise Levels at Selected Receptors 73

14 Sound Insulation of Typical Windows 74

15 EPC2 Process Plant Equipment Data Log Book 78

16 Minimum Insertion Loss Required for each Acoustic Insulation

Class

86

d