SERVICES
Planning Applications
Most of the work undertaken by Auracle Acoustics is connected with planning applications or environmental impact assessments for residential and commercial / industrial developments.
For proposed residential developments it is often necessary to consider the potential for the development to be affected by noise from existing noise sources such as roads, railways and industrial sources. For proposed commercial and industrial developments it is normally necessary to consider the potential for noise from the development to affect existing sensitive receptors such as residences, hospitals, schools and places of worship.
An acoustics assessment for a development typically involves:
• Liaison with the environmental health department of the local planning authority
• Confirmation of noise levels by monitoring or from manufacturers’ data;
• Prediction of noise levels at potentially affected sensitive receptors using prediction methods that accord with national guidance documents;
• Assessment of the predicted noise levels at potentially affected sensitive receptors in accordance with the guidance provided by national guidance documents and the guidance adopted by the local planning authority concerned;
• Reporting of findings including details of the monitoring, prediction and assessment exercise, along with details of any mitigation measures that may be required.
We can also provide expert witness assistance at planning appeals.
Noise Monitoring
Sources of environmental noise that are commonly encountered include road traffic, railways, aircraft and industrial noise sources such as factories and power stations.
Auracle Acoustics undertakes the monitoring of noise from sources such as these using state of the art precision integrating equipment. As well as logging data in terms of the normal parameters such as dB LAeq, dB LA90, dB LAmax etc, the equipment makes a contemporaneous audio recording which can be used subsequently to assist in the detailed analysis of the results obtained.
Using software, the results can be analysed by applying various auditing periods from 5 minutes to 60 minutes and for daytime and night-time periods. Additionally, using software, different noise sources contributing to the results can often be identified and analysed individually, meaning that noise spectra for different sources can normally be isolated from a single results set. Noise from extraneous noise events can also be identified and excluded when the results are analysed subsequent to the noise monitoring exercise.
Noise Modelling
Auracle Acoustics normally undertakes noise predictions with the aid of the NoiseMap noise modelling software package. The noise models includes ground contours and other topographical features such as buildings and acoustic barriers, and can be used to predict noise levels over large areas for line sources such as roads and railways and point sources such as construction site workings and industrial noise sources. The predictions are undertaken in accordance with appropriate guidance documents.
The use of a noise model on a project means that different mitigation strategies can be readily compared, which can be particularly useful in situations were a number of noise sources are present. Noise models can also be readily updated to reflect changes in proposed developments that commonly occur as projects are progressed.
BACKGROUND
Introduction
The term 'acoustics' may be used to describe the field of study covering the generation, propagation and control of vibrational waves in gases, liquids and solids.
The term 'sound' is generally used to refer to those acoustic waves which can be perceived by the human hearing system, nominally ranging in frequency from 20 Hz to 20 kHz and most commonly propagating in air. The field of acoustic therefore includes this study of sound, but also includes topics such as vibration (which may occur in the ground or in buildings, vehicles and other structures, and may be at very low frequencies), ultrasonics (vibrations in air or other materials which have frequencies above 20 kHz) and specialist areas such as electro-acoustics, underwater acoustics and the acoustics of musical instruments.
The most common unit if measurement used in acoustics is the decibel (dB) which is used to express sound pressure levels, sound power levels and vibration levels as a ratio compared to standard reference levels. The decibel scale is a logarithmic scale (rather than a linear scale) and has been adopted because it enables the very large ranges of values found in acoustics (many orders of magnitude for audible sounds for instance) to be expressed using relatively small numbers (up to about 120 or so for audible sounds for instance). Additionally, levels of vibration are often expressed in terms such as acceleration, displacement and peak particle velocity.
An increase or decrease of 3 dB is equivalent to a doubling or halving of acoustic energy, while an increase or decrease of 10 dB is equivalent to a ten-fold increase or decrease of acoustic energy. Under free-field conditions (ie outdoors away from acoustically reflective surfaces) sound pressure levels due to propagation from a point source (eg at a sufficient distance from an item of mechanical plant) reduce by 6 dB per doubling of distance. Under the same conditions sound pressure levels due to propagation from a line source (eg a road or railway) reduce by 3 dB per doubling of distance.
Environmental Acoustics
The field of environmental acoustics may be taken to include noise and vibration arising from sources such as transportation, industrial premises, minerals extraction sites, construction and demolition sites, power stations and waste transfer and waste handling facilities such as landfills, waste incinerators and civic amenity sites.
Potentially affected sensitive receptors include housing (existing or proposed), schools, hospitals and places of worship. It is frequently necessary to control noise and vibration arising from new or existing sources such that impacts at new or existing sensitive receptors are satisfactory and do not exceed specific target levels.
Under planning legislation individual local planning authorities have a responsibility to take account of potential noise and vibration impacts when considering applications for new developments. To this end they may adopt specific target levels to control noise and vibration impacts (which may be set out in the Local Plan or corresponding documents) or they may rely solely on the guidance provided by central government.
Each local planning authority also has a responsibility to patrol its area and to investigate complaints which may arise from any source of noise and / or vibration. In this context local authorities rely on nuisance legislation.
BRITISH STANDARDS
& OTHER GUIDANCE
British Standards
British Standards that provide guidance that is relevant to environmental noise and vibration assessments include (click to see full standard):
• BS8233: 2014: ‘Guidance on sound insulation and noise reduction for buildings’;
• BS4142: 2014 ‘Methods for rating and assessing industrial and commercial sound’;
• BS5228: 2009: ‘Code of practice for noise and vibration control on construction and open sites’;
• BSBS6472-1: 2008 ‘Guide to evaluation of human exposure to vibration in buildings - Part 1: Vibration sources other than blasting’ ;
• BS7445-1: 2003: ‘Description and measurement of environmental noise - Guide to quantities and procedures’;
• BS7445-2: 1991: ‘Guidance on the acquisition of data for measuring and describing environmental noise relevant to general land use’ ;
• BS7445-3:1991: ‘Guidelines for specification of noise limits and acquisition of data’
National Planning Policy Framework
The current edition of the National Planning Policy Framework was published on 20 July 2021 and supersedes previous editions of the including the original that was issued in March 2012.
Paragraph 1 of the document states:
“The National Planning Policy Framework sets out the Government’s planning policies for England and how these should be applied. It provides a framework within which locally-prepared plans for housing and other development can be produced.”
Paragraph 7 of the document states:
“The purpose of the planning system is to contribute to the achievement of sustainable development. At a very high level, the objective of sustainable development can be summarised as meeting the needs of the present without compromising the ability of future generations to meet their own needs. At a similarly high level, members of the United Nations – including the United Kingdom – have agreed to pursue the 17 Global Goals for Sustainable Development in the period to 2030. These address social progress, economic well-being and environmental protection.”
Three overarching objectives of the planning system are identified, an economic objective, a social objective and an environmental objective.
Paragraph 10 of the document states:
“So that sustainable development is pursued in a positive way, at the heart of the Framework is a presumption in favour of sustainable development (paragraph 11).”
As is to be expected, much of the document deals with strategic planning issues such as:
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achieving sustainable development;
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delivering a sufficient supply of homes;
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building a strong, competitive economy;
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ensuring the vitality of town centres;
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promoting healthy and safe communities;
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promoting sustainable transport;
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supporting high quality communications;
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making effective use of land;
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achieving well-designed places;
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protecting Green Belt land;
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meeting the challenge of climate change, flooding and coastal change;
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conserving and enhancing the natural environment
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conserving and enhancing the historic environment; and
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facilitating the sustainable use of minerals.
Specific references to noise are limited, but occur in:
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paragraph 174, which states:
“Planning policies and decisions should contribute to and enhance the natural and local environment by:
e) preventing new and existing development from contributing to, being put at unacceptable risk from, or being adversely affected by, unacceptable levels of soil, air, water or noise pollution or land instability. Development should, wherever possible, help to improve local environmental conditions such as air and water quality, taking into account relevant information such as river basin management plans”; -
paragraph 185, which states:
“Planning policies and decisions should also ensure that new development is appropriate for its location taking into account the likely effects (including cumulative effects) of pollution on health, living conditions and the natural environment, as well as the potential sensitivity of the site or the wider area to impacts that could arise from the development. In doing so they should:
a) mitigate and reduce to a minimum potential adverse impacts resulting from noise from new development – and avoid noise giving rise to significant adverse impacts on health and the quality of life;
b) identify and protect tranquil areas which have remained relatively undisturbed by noise and are prized for their recreational and amenity value for this reason”; -
paragraph 210, which states:
“Planning policies should:
g) when developing noise limits, recognise that some noisy short-term activities, which may otherwise be regarded as unacceptable, are unavoidable to facilitate minerals extraction”; and -
paragraph 211, which states:
“When determining planning applications, great weight should be given to the benefits of mineral extraction, including to the economy. In considering proposals for mineral extraction, minerals planning authorities should:
c) ensure that any unavoidable noise, dust and particle emissions and any blasting vibrations are controlled, mitigated or removed at source, and establish appropriate noise limits for extraction in proximity to noise sensitive properties”.
Additionally, the document refers to the Explanatory Note to the Noise Policy Statement for England.
Noise Policy Statement for England
The Noise Policy Statement for England was published by the Department for Environment, Food and Rural Affairs (Defra) in March 2010. The complete document includes the Policy Statement itself and an Explanatory Note.
Key concepts used in the NPSE are:
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NOEL or “no observed effect”, meaning the level (of noise) below which no effect on health or quality of life can be detected;
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LOAEL or “lowest observed adverse effect”, meaning the level (of noise) above which adverse effects on health and quality of life can be detected; and
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SOAEL or “significant observed adverse effect”, meaning the level (of noise) above which significant adverse effects on health and quality of life can occur.
The first aim of the NPSE is to:
“Avoid significant adverse impacts on health and quality of life from environmental, neighbour and neighbourhood noise within the context of the policy on sustainable development”.
The second aim of the NPSE is to:
“Mitigate and minimise adverse impacts on health and quality of life from environmental, neighbour and neighbourhood noise within the context of the policy on sustainable development”.
The third aim of the NPSE is to:
“Where possible, contribute to the improvement of health and quality of life through the effective management of environmental, neighbour and neighbourhood noise within the context of the policy on sustainable development”.
The second aim refers to the situation lies somewhere between LOAEL and SOAEL.
However, paragraph 2.3 of the Explanatory Note makes it clear that the approach to the minimisation of noise from environmental and related sources should be reasonable and balanced in stating:
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“2.3 Furthermore, the broad aim of noise management has been to separate noise sources from sensitive noise receivers and to “minimise” noise. Of course, taken in isolation and to a literal extreme, noise minimisation would mean no noise at all. In reality, although it has not always been stated, the aim has tended to be to minimise noise ”as far as reasonably practical”. This concept can be found in the Environmental Protection Act 1990, where, in some circumstances, there is a defence of “best practicable means” in summary statutory nuisance proceedings.
Professional Practice Guidance on Planning & Noise
This guidance document was published jointly by Association of Noise Consultants (ANC), the Institute of Acoustics (IOA) and the Chartered Institute of Environmental Health (CIEH) in May 2017. The foreword of the document states:
"This Professional Practice Guidance on Planning and Noise (ProPG) has been produced to provide practitioners with guidance on a recommended approach to the management of noise within the planning system in England."
"The National Planning Policy Framework (NPPF) encourages improved standards of design. The CIEH, IOA and the ANC have worked together to produce this guidance which encourages better acoustic design for new residential development and aims to protect people from the harmful effects of noise."
"Good acoustic design is about more than the numbers. It is a holistic design process that creates places that are both comfortable and attractive to live in, where acoustics is considered integral to the living environment."
"Good acoustic design can involve, for example, careful site layouts and better orientation of rooms within dwellings. Good acoustic design does not mean “gold plating” or significantly increasing costs. This guidance seeks to encourage and promote design outcomes that are proportionate and reasonable in the particular circumstances of each development site.”
To these ends, Chapter 2 the document sets out a recommended approach for new residential development, which includes two sequential stages in the overall approach, which are:
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Stage 1 - an initial noise risk assessment of the proposed development site; and
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Stage 2 - the systematic consideration of four key elements in the site layout and design process.
The noise risk assessment of Stage 1 is to “provide an indication of the likely risk of adverse effects from noise were no subsequent mitigation to be included as part of the development proposal. It should indicate whether the proposed site is considered to pose a negligible, low, medium or high risk from a noise perspective. The document provides guidance on this assessment in graphical form in Figure 1.
The four elements of Stage 2 (which should be undertaken in parallel) are:
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Element 1 – demonstrating a “Good Acoustic Design Process”;
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Element 2 – observing internal “Noise Level Guidelines”;
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Element 3 – undertaking an “External Amenity Area Noise Assessment”; and
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Element 4 – consideration of “Other Relevant Issues”.
In this context the document states:
“2.5 The approach is underpinned by the preparation and delivery of an “Acoustic Design Statement” (ADS). An ADS for a site assessed as high risk should be more detailed than for a site assessed as low risk. An ADS should not be necessary for a site assessed as negligible risk."
“2.6 Having followed this approach to its end, it is envisaged that noise practitioners will then have a choice of one of four possible recommendations to present to the decision maker. In simple terms the choice of recommendation is as follows: grant without conditions, grant with conditions, “avoid” or “prevent” (see Section 3).”
(Section 3 provides additional information on the four possible recommendations that are to me made by the noise practitioner to the decision maker.)
Paragraph 2.12 of the document states:
“2.12 It is important that the assessment of noise risk at a proposed residential development site is not the basis for the eventual recommendation to the decision maker. The recommended approach is intended to give the developer, the noise practitioner, and the decision maker an early indication of the likely initial suitability of the site for new residential development from a noise perspective and the extent of the acoustic issues that would be faced. Thus, a site considered to be high risk will be recognised as presenting more acoustic challenges than a site considered as low risk. A site considered as negligible risk is likely to be acceptable from a noise perspective and need not normally be delayed on noise grounds. A potentially problematical site will be flagged at the earliest possible stage, with an increasing risk indicating the increasing importance of good acoustic design.”
Paragraph 2.33 of the document states:
“2.33 It should be noted that the acoustic performance of the building envelope will be reduced in the event windows are opened for ventilation or cooling purposes, typically reducing the insulation to no more than 10 to 15 dB(A). Most residents value the ability to open windows at will, for a variety of reasons, and LPAs should therefore normally request that designers principally aim, through the use of good acoustic design, to achieve the internal noise level guidelines in noise-sensitive rooms with windows open. Where internal noise levels are assessed with windows closed the justification for this should be included in the ADS.”
Section 3 sets out four possible recommendations that noise practitioners should make to decision makers, which are:
A. Planning consent may be granted without any need for noise conditions;
B. Planning consent may be granted subject to the inclusion of suitable noise conditions;
C. Planning consent should be refused on noise grounds in order to avoid significant adverse effects (“avoid”); or
D. Planning consent should be refused on noise grounds in order to prevent unacceptable adverse effects (“prevent”).
A summary of the overall ProPG approach is illustrated in Figure 4 of the document.
Section 4 of the document deals with the provision of specialist assistance.
Appendix A of the ProPG is entitled “Dealing with Noise Events” provides additional information on the consideration of individual noise events such as those arising from transportation sources at night, where sleep disturbance may be an issue.
Acoustics, Ventilation and Overheating Residential Design Guide
Planning Practice Guidance on Noise provided on the UK Government website
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