environmental noise assessment - proposed residential ... · 2.6 the “noise policy aims” of the...

Environmental Noise

Assessment - Proposed

Residential Development

on Land at Yarmouth

Road, Blofield, Norfolk.

D F Sharps MIOA

CEng FIMechE FIOA

Acoustic consultant

Sharps Acoustics LLP

16 March 2016

exyar

0488

Table of contents

1.0 Introduction ............................................................................................................. 1

2.0 Assessment methodology ....................................................................................... 2

3.0 An analysis of noise immissions across the application site ................................... 6

4.0 Assessment of impact and recommended noise mitigation measures ................... 8

5.0 Conclusions ........................................................................................................... 10

6.0 Glossary of terms .................................................................................................. 11

Appendices

Appendix A Aerial view of site

Appendix B Site layout and location plans

Appendix C Computer model results without earth mounding

Appendix D Survey details

Appendix E Noise contours with earth mounding

Proposed residential development, Yarmouth Road, Blofield.

Page 1

1.0 Introduction

1.1 Sharps Acoustics LLP (“SAL”) has been commissioned by Bovis and ‘A G H Smith, J E

Smith, R G Smith & SLA Property Company Ltd’ (the “Applicants”) to undertake a noise

assessment in relation to the planned residential development (the “Application Scheme”) at

Yarmouth Road, Blofield, Norfolk (the “Application Site”).

1.2 An assessment of a planned employment development adjacent to the residential site is the

subject of separate report.

1.3 SAL has previously provided a proof of evidence to an inquiry which considered residential

development on the Application Site. This proof is dated 8 November 2012. That appeal

scheme was made in outline for a mixed residential and Use Class B1 development. The

layout of that scheme had residential units at the eastern end of the site, set back from the

A47 with B1 development at the western end of the site. The appeal was allowed with

conditions.

1.4 The current Application Scheme is very similar to the residential component of the scheme

taken to inquiry. Therefore this report closely follows the structure of the proof of evidence

to the inquiry but has been brought up-to-date incorporating the provisions of new policies

and a revised British Standard 8233, introduced since November 2012.

1.5 An aerial view of the site is attached at Appendix A. An indicative site layout plan and a

location plan are attached at Appendix B.

1.6 It can be seen from the aerial view and layout plan that the Application Site is located

between the Yarmouth Road, which is to the south of the site, and the A47, which is to the

north-west of the site. This report addresses the noise impact from traffic on the A47 on the

residents of the proposed dwellings.

1.7 The Yarmouth Road is lightly trafficked and the noise impact from this road link is negligible.

1.8 A full planning permission has been granted for a public house and restaurant, and a food

store, along the western boundary of the site. The precise details of these proposals are not

yet known. However, the likely noise impact associated with this planned use is considered

in this report.

1.1 This report is structured as follows:

� Section 2.0 provides an analysis of assessment methods and criteria.

� Section 3.0 provides an analysis of traffic noise immissions across the application site –

both with and without earth mound mitigation measures. Conventionally, noise levels


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from transportation noise sources are determined by prediction rather than survey.

However, this section contains details of surveyed noise emission levels which were

used to validate the predicted noise levels.

� The assessment of noise impact and recommendations for mitigation are provided at

Section 4.0.

� Assessment conclusions are provided at Section 5.0.

� A glossary of terms is provided at Section 6.0.

2.0 Assessment methodology

National Planning Policy Framework (NPPF)

2.1 The National Planning Policy Framework (NPPF), released on 27th March 2012, indicates

that local planning authorities should base their decisions and policies relating to planned

development so as to:

� aim to avoid noise from giving rise to significant adverse impacts on health and quality

of life as a result of new development;

� mitigate and reduce to a minimum other adverse impacts on health and quality of life

arising from noise from new development, including through the use of conditions;

� recognise that development will often create some noise and existing businesses

wanting to develop in continuance of their business should not have unreasonable

restrictions put on them because of changes in nearby land uses since they were

established; and

� identify and protect areas of tranquillity which have remained relatively undisturbed by

noise and are prized for their recreational and amenity value for this reason.

2.2 The NPPF does not provide prescriptive or quantitative advice on how to achieve its principal

objective of avoiding significant adverse impacts on health and quality of life. Therefore, it

is necessary to consider advice in other guidance documents. This advice is discussed at

paragraph 2.18 to 2.32, below.

The Noise Policy Statement for England (NPSE)

2.3 Footnote 27 on page 29 of the NPPF refers to the Noise Policy Statement for England

(NPSE), prepared by DEFRA, dated March 2010.


Page 3

2.4 Paragraph 1.5 of the NPSE states that it applies to all forms of noise including environmental

noise, neighbour noise and neighbourhood noise. In this respect the document is similar to

the World Health Organisation (WHO) “Guidelines for Community Noise” – discussed below.

2.5 The NPSE explains that the WHO defines health as “a state of complete physical, mental

and social well-being and not merely the absence of disease or infirmity” (NPSE paragraph

2.12).

2.6 The “Noise Policy Aims” of the NPSE (NPSE paragraphs 2.22 to 2.24) can be summarised

as follows:

� avoid significant adverse impacts on health and quality of life…”;

� “mitigate and minimise adverse impacts on health and quality of life…”; and

� “where possible, contribute to the improvement of health and quality of life.

2.7 The NPSE makes a distinction between “quality of life”, which is a subjective measure, and

“health”, which refers to physical and mental well-being.

2.8 Impacts that may result from noise such as “annoyance” and “sleep disturbance” are both

quality of life and health effects in this sense.

2.9 The NPSE introduces the concepts of the “no observed effect level” (NOEL); the “lowest

observed adverse effect level” (LOAEL) and a “significant observed adverse effect level”

(SOAEL).

2.10 It is the last of these criteria – the SOAEL – that is the level above which significant adverse

effects on health and quality of life occur that equates to the “first aim of the NPSE” paragraph

2.6 above) and the first objective of the NPPF (paragraph 2.1 above).

2.11 The “second aim of the NPSE” is to mitigate and minimise adverse impacts between LOAEL

and SOAEL.

2.12 The NPSE does not provide noise levels or limits above which SOAEL occurs. Indeed, the

document advises that it is not possible to have a single objective noise-based measure that

defines SOAEL (NPSE paragraph 2.22). Therefore, it is necessary to refer to other advisory

documents in order to seek to define such levels. These are discussed below.

National Planning Practice Guidance (NPPG)

2.13 The NPPG was released on 6th March 2014 and was last updated in December 2014, i.e.

after the proof of evidence in 2012.


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2.14 This document reinforces the concept of NOEL, LOAEL and SOAEL and defines a person’s

perception at these different effect levels.

2.15 It is notable that the NPPG describes the NOEL as “noise can be heard, but does not cause

any change in behaviour or attitude”, whereas at a LOAEL “noise can be heard and causes

small changes in behaviour and/or attitude, e.g. turning up volume of television; speaking

more loudly…” The former is described as “noticeable and not intrusive” whereas the latter

is described as “noticeable and intrusive”.

2.16 A “significant” effect is described as “noticeable and disruptive” resulting in “a material

change in behaviour and/or attitude…”

2.17 The NPPF, NPSE and NPPG do not ascribe noise levels to any of the effects discussed

within the documents. Therefore, it is necessary to consider other guidance which attributes

noise levels to health effects such as annoyance during the day or sleep disturbance at night.

World Health Organisation – Guidelines for Community Noise

2.18 This document contains the most comprehensive and up to date guidance on the

assessment of environmental noise.

2.19 The WHO Guidelines are particularly applicable in relation to the NPPF, NPSE and NPPG

advice since it considers impact in terms of health effects (health being defined in its widest

sense discussed at paragraph 2.5 above - including annoyance during the day (defined as

0700 to 2300 hours) and sleep disturbance at night (defined as 2300 to 0700 hours).

2.20 The WHO Guidelines contain a matrix of “guideline values” for effects from noise within

different environments. These guideline values are set at the lowest level that produces an

adverse effect, that is, the “critical health effect”. As such the values suggested in the

Guidelines are thresholds below which effects such as annoyance can be assumed to be

negligible. As such the WHO guideline values are equivalent to the NPSE LOAEL.

2.21 Unfortunately, the WHO Guidelines do not provide advice as to what constitutes a

“significant” effect; it is necessary to consider other guidance in this respect. This is

discussed at paragraphs 2.25 and 2.26 below.

2.22 The WHO guideline values for moderate and serious annoyance during the daytime are

LAeq16hrs = 50 and 55 dB, respectively. The WHO guideline values for night are LAeq8hr

= 45 dB and LAMAX = 60 dB.

2.23 The WHO guideline values for day can be considered to be either facade levels (when

assessing effects inside dwellings) or free-field levels (when assessing effects in gardens).

The WHO guideline values for night are façade levels (i.e. outside bedroom windows).


Page 5

NPL audit report of the WHO Guidelines

2.24 This National Physical Laboratory (NPL) document, which was commissioned by the

Department of the Environment Transport and the Regions (DETR), contains a section on a

“Guide to the Interpretation of the WHO Guidelines”. This interpretation related to a 1995

draft of the Guidelines but this was not materially different to the final 1999 Guidelines.

2.25 The summary of this section of the NPL report states:

“In essence, the WHO guidelines represent a consensus view of international expert

opinion on the lowest threshold noise levels below which the occurrence rates of particular

effects can be assumed to be negligible. Exceedances of the WHO guideline values do

not necessarily imply significant noise impact and indeed, it may be that significant

impacts do not occur until much higher degrees of noise exposure are reached.”

2.26 “Much higher degrees of exposure” is not defined by the NPL. However, in SAL’s judgment

this indicates a 10 dB difference (a 10 dB difference being roughly a doubling of loudness).

Therefore, SOAEL values are 10 dB higher than the WHO guideline values.

BS 8233:2014

2.27 BS 8233 “Guidance on sound insulation and noise reduction for buildings” is specifically

aimed at the acoustic design of new or refurbished buildings - residential and other noise

sensitive properties. It was revised in 2014 with changes including different design targets

now called “guideline values” so as to bring the standard in line with the WHO Guidelines.

This revised version of the standard has been employed in this current assessment.

2.28 BS 8233 provides guideline values for living areas and bedrooms and for external amenity

areas such as gardens. The BS 8233 guideline values were based on the WHO guideline

values, discussed above.

2.29 Table 4 of the standard provides “desirable” internal guideline values as shown in Table 1

below:

Table 1 BS 8233 guideline values

Activity Location 07:00 to 23:00 hrs 23:00 to 07:00 hrs

Resting Living room 35 dB LAeq16hour -

Dining Dining room/area 40 dB LAeq16hour -

Sleeping (daytime resting)

Bedroom 35 dB LAeq16hour 30 dB LAeq8hour


Page 6

2.30 These guideline values are different to those within the previous version of BS 8233.

2.31 The standard states that the guideline values apply to noise that is steady and without a

particular character. The noise climate across the Application Site is steady and broadband

in nature. Therefore, the provisions of BS 8233 are applicable.

2.32 When assessing noise from industrial or commercial uses, BS 8233 recommends that “rating

levels” are determined using the provisions of BS 4142.

2.33 The advice at paragraph 7.7.3.2 of the standard is as follows:

“For traditional external areas that are used for amenity space, such as gardens and

patios, it is desirable that the external noise level does not exceed 50 dB LAeq,T, with an

upper guideline value of 55 dB LAeq,T which would be acceptable in noisier

environments. However, it is also recognized that these guideline values are not

achievable in all circumstances where development might be desirable. In higher noise

areas, such as city centres or urban areas adjoining the strategic transport network, a

compromise between elevated noise levels and other factors, such as the convenience of

living in these locations or making efficient use of land resources to ensure development

needs can be met, might be warranted. In such a situation, development should be

designed to achieve the lowest practicable levels in these external amenity spaces, but

should not be prohibited.”

2.34 The above guideline values are applicable to all noise and not just to noise that is steady

and without a particular character.

2.35 The BS 8233 “desirable” internal and external guideline values are most closely aligned with

LOAEL values – as are the WHO guideline values on which they are based.

3.0 An analysis of noise immissions across the application site

Introduction

3.1 The road traffic assessment section of the proof of evidence is reproduced below – with

minor modifications reflecting the report format and up-to-date information.

Road traffic - by prediction

3.2 Traffic noise levels are usually predicted using “Calculation of Road Traffic Noise” (CRTN).

This document allows the accurate prediction of traffic noise from parameters such as: traffic

flow, percentage of heavy vehicles, traffic speed, road surface, and distance.

3.3 Paragraph 3 of CRTN states that prediction (rather than measurement) is the preferred

technique for the assessment of traffic noise emission levels. This is because traffic


Page 7

conditions can vary considerably and a surveyed noise level can only measure the noise

level for that particular set of traffic conditions. Calculating noise levels over a large site

which is undulating is cumbersome and, so, this is usually undertaken using a computer

program. A proprietary program called SoundPLAN enabled this process.

3.4 In modelling the traffic noise emission levels over the application site, a digitised ground map

of the site and A47 was imported to the program.

3.5 Traffic flows and other highway data was provided by MLM Multidisciplinary Consulting and

imported to the program.

3.6 The results of the noise model (without earth mounding) over the Application Site are

displayed at Appendix C. Noise models are displayed of noise levels during the day and

night.

Road traffic - by survey

3.7 A survey was undertaken on site on 5th September 2012. Survey details are provided at

Appendix D.

3.8 The weather during the survey was ideal for noise measurement being dry, warm (17

degrees Celsius), and with a light (< 2 metre/second) breeze blowing from the north-west

(from the A47 towards the site).

3.9 These conditions represent ideal noise propagation conditions allowing worst-case traffic

noise levels to be surveyed.

3.10 Measurements were undertaken at 10 metres from the A47 kerb-side in accordance with the

provisions of CRTN “Shortened measurement procedure” (CRTN paragraphs 43 and 44).

3.11 The LA10 levels recorded in the three consecutive hours from 1300 to 1600 were 80.2, 78.7

and 79.0 dB with an average value of 79.3 dB rounded to 79 dB. The equivalent LA10 18hr

level is 78 dB and the LAeq16hr level, 76 dB.

3.12 The surveyed traffic noise level at 10 metres from the A47 was within 1 dB of the predicted

noise level. Bearing in mind the size of the survey sample and variation in traffic flows, day

to day, this is a good correlation.

3.13 Short-term noise levels were also recorded at locations across the site, back from the A47

kerb-side, along the footpath, at the following distances: 36 metres, 66 metres, 96 metres

and 126 metres. The results are presented in Appendix D. The measured levels were similar

to those predicted – displayed at Appendix C.


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Noise from the public house, restaurant and food-store

3.14 See section 4.0 below.

4.0 Assessment of impact and recommended noise mitigation measures

Introduction

4.1 The section of the proof of evidence, which addresses the noise impact from road traffic, is

reproduced below – with minor modifications reflecting the report format and up-to-date

information. An assessment has also been made of likely noise impact from the public house

and restaurant for which planning permission has been granted at the western boundary of

the site.

Traffic noise to external areas

4.2 The site is such that the majority of the A47 is screened because the road is lower than the

ground directly adjacent to the road. The exception is a short section in the middle of the

site’s north-western boundary where the A47 is at a similar level to the adjacent ground.

4.3 SAL recommended at the inquiry that this gap be in-filled with an earth mound of a height

equivalent to the heights of the existing landforms either side of the gap. This

recommendation still stands.

4.4 The earth mound will provide two benefits. Firstly, it will reduce traffic noise levels at the

nearest properties to the gap. The reduction in noise levels will not be large but will be

worthwhile. Secondly, the proposed earth mound will reduce the visual impact, and

consequently the perceived noise impact from traffic on the A47.

4.5 The results of the noise model, with an earth screen mound, are displayed at Appendix E,

both for day and night. It can be seen from the modelled emission levels that the maximum

traffic noise levels at the façade of any residential property are LAeq16hr = 62 dB (day) and

LAeq8hr = 56 dB (night).

4.6 Where it is not possible to obtain such an arrangement, then SAL recommends that good

quality timber fencing is employed. This fencing should be 1.8 metres high. Such fencing

would reduce noise levels by a minimum of 7 dB, depending on receiver location within the

garden. Again, this would ensure that the noise levels within gardens would comply with the

BS 8233 “desirable” upper guideline value of 55 dB.

Traffic noise to internal areas

4.7 BS 8233 advises that the reduction in road traffic noise level from outside to inside with a

conventional building envelope, comprising of wall and windows will be limited by the window


Page 9

performance. The BS assumes a reduction from the windows of RW = 33 dB. In SAL’s

experience, this is the insulation that would be provided by a standard thermal glazed

window with good seals to all opening casements.

4.8 BS 8233 advises that the internal noise level will be a function of the external level minus a

33 dB loss from the window. Therefore, the worst-case daytime noise level within any of the

proposed dwellings will be 62 – 33 = 29 dB.

4.9 This internal noise level during the day would be within the BS 8233 guideline value of 35

(see Table 1 above).

4.10 The internal noise level at night would be 56 – 33 = 23 dB. This traffic noise immission level

is well within the BS 8233 guideline value of 35 dB (see Table 1 above).

4.11 BS 8233:2014 advises that the loss through a partially open window is 15 dB. Therefore,

the worst-case internal noise levels with windows open would be 62 – 15 = 47 dB (day) and

56 – 15 – 41 dB (night). These internal noise levels are above the BS 8233 guideline value

for day and night of 35 dB (see Table 1 above).

4.12 In such a case, BS 8233 advises that an alternative form of rapid ventilation system should

be considered, such as a mechanical system.

4.13 SAL recommends that it is appropriate to install a Mechanical Ventilation and Heat Recovery

(MVHR) system in properties where internal noise levels, with windows open, would exceed

the BS 8233 guideline value for day and night. The Applicants have accepted this

recommendation.

4.14 On this basis, MVHR systems should be installed to properties within the LAeqT = 35 + 15

= 50 dB contour line.

4.15 The system typically consists of a fan within the roof area of a property which extracts air

from the premises via small bore ductwork built into the building. The extracts are usually in

“wet rooms” such as kitchens, bathrooms and toilets. The fan “pulls” a negative pressure in

the whole building so that air flows from living areas and bedrooms is extracted via the extract

grilles in the various wet rooms.

4.16 The system may be designed such that the extracted air is filtered and treated with a

percentage of the air being returned to the living areas (hence the “heat recovery”). Air that

is not circulated is usually discharged via small tile roof vents.

4.17 The extracted air is also part replaced by fresh air supplied via intake grilles in living rooms

and bedrooms. These are usually located within the window frames above the window

panes.


Page 10

4.18 MVHR systems are now being installed as a matter of course into buildings in order to comply

with the requirements of recent Building Regulations relating to energy conservation and

building air-tightness. In this respect, the system is sustainable.

Noise from the public house, restaurant and food-store

4.19 In the absence of a detailed site layout of the public house, restaurant and food-store

scheme, and without a knowledge of intended operating times it is difficult to assess to

impact.

4.20 However, access and egress to these uses will be directly from the Yarmouth Road. Traffic

flows to and from such a facility are likely to be relatively low and would not be likely to result

in a material noise impact.

4.21 The residential application is outline. Appropriate noise assessments will support the future

reserved matters application and the detailed design will deal with any required mitigation

measures sufficient to protect the amenities of future occupiers of the scheme.

5.0 Conclusions

5.1 Recommendations have been made for mitigation of traffic noise from the A47 in the form

of: i) an earth mound which would close the current gap in the natural landform alongside

the A47; and ii) a Mechanical Ventilation and Heat Recovery system in the most noise

affected properties.

5.2 At the detailed design stage it is recommend that the layout of the residential development

is optimised so that gardens are screened from the A47 by properties or garages. If this is

not practical, then it is recommended that gardens are screened by good quality timber

fences of 1.8 metres height.

5.3 The above mitigation measures are entirely conventional and usual with modern residential

development.

5.4 The mitigation measures will ensure that external and internal amenity areas would be fully

protected from traffic noise - external and internal traffic noise immission levels would be

below (i.e. within) the “desirable” guideline values set out in BS 8233.

5.5 The BS 8233 guideline values are based on those within the WHO Guidelines.

5.6 Both sets of guideline values are aligned with the Government policy “low observed adverse

effect level”. As such, there would be “no observed effect” on the properties within the

Application Scheme as a result of A47 traffic noise: “noise can be heard, but does not cause

any change in behaviour or attitude”.


Page 11

5.7 Traffic noise impinging on the Application Scheme would be well below “significant observed

adverse effect levels –the Government policy is to avoid such noise levels.

5.8 Little detail is available of the public house, restaurant and food store schemes to the west

of the residential site.

5.9 At the detailed design stage of the residential scheme it is recommend that noise mitigation

is designed and incorporated so as to protect the amenities of future occupiers.

6.0 Glossary of terms

Ambient noise: The all-encompassing sound associated with a given environment at a specified time,

being usually a composite of sound from many sources, near or far.

Amplitude: The maximum value of a sinusoidal quantity.

Audible sound: 1) Acoustic oscillations of such a character as to be capable of exciting the sensation

of hearing. 2) Sensation of hearing excited by sound waves.

Average sound level: See equivalent continuous sound level.

A weighting: A frequency response provided in a sound level meter which reflects the sensitivity of

human hearing to different frequencies.

A-weighted sound level: The sound level (otherwise known as sound pressure level) obtained by use

of A-weighting. Decibel unit is dB. Often, the unit symbol is followed by the letter A in round brackets,

i.e. dB(A).

Background sound level (bsl): The total level of noise from all other sources other than the particular

source of interest. The index symbol is L90. In BS 4142 the bsl is described as “The a-weighted

sound pressure level of the residual noise at the assessment position that is exceeded for 90% of a

given time interval, T, measured using time weighting, F, and quoted to the nearest whole number of

decibels”. This index is denoted LA90.

Decibel: A unit of level which denotes the ratio between two quantities that are proportionate to

power; the number of decibels is 10 times the logarithm of this ratio. One decibel is one tenth of a

Bel. Unit symbol for decibel: dB.

Divergence: The spreading of sound waves from a source in a free-field, resulting in a diminution in

sound level with increasing distance from the source. This reduction in sound level is 6 dB per

doubling of distance from a point source (such as a stationary vehicle) and 3 dB per doubling of

distance from a line source (such as vehicles on a road).


Page 12

Equivalent continuous sound level: The level of a steady sound which, in a stated time period, has the

same sound energy as the time-varying sound. The index symbol is LeqT. When A-weighted the

symbol becomes LAeqT with the unit symbol being dB (Note: Alternatively LeqT dB(A)).

Facade noise level: The sound level at a facade (usually taken to be 1 metre from the facade (see for

example BS 4142). A facade level is taken to be 3 dB higher than the level in the absence of the

facade (i.e. the equivalent free-field level) although “Calculation of Road Traffic Noise” assumes a 2.5

dB difference.

Free-field: A sound field in a homogeneous isotropic medium whose boundaries exert a negligible

influence on the sound waves. In practice, a field in which the effects of the boundaries are negligible

over the frequencies of interest. Often taken to be > 3.5 metres from a building facade (ref: BS 4142).

Frequency: Of a function periodic in time, the number of times the quantity repeats itself in one

second. The unit of frequency is the hertz (Hz) with 1 hertz = 1 cycle per second.

Frequency weighted sound level: The root-mean-square of the instantaneous sound (pressure) level,

time weighted (slow, fast, impulse or peak) and frequency-weighted with a standard frequency

characteristic (the most often used being “A-weighting”).

Instantaneous sound (pressure) level: Ten times the logarithm of the square of the ratio of the

instantaneous sound pressure to the reference sound pressure of 20 micropascals (µPa). Unit is the

decibel (dB).

Inverse square law: In the far-field of a source, under free-field conditions, the sound intensity varies

inversely with the square of the distance from the source; this results in a decrease in sound level of 6

dB for each doubling of distance from the source.

Masking: The process by which the threshold of hearing of one sound is raised by the presence of

another sound.

Maximum A-weighted sound level: The greatest A-weighted sound level measured on a sound level

meter during a designated time interval or event. The time averaging is usually “fast” but can

sometimes be “slow” (e.g. measurement of aircraft noise).

Noise: Any undesired or unwanted sound.

Octave band sound level: The sound (pressure) level within an octave frequency band. Octave band

centre frequencies include: 31.5 Hz, 63 Hz, 1125 Hz, 250 Hz, 500 Hz, 1000 Hz (otherwise shown as 1

KHz), etc.

Octave band spectrum: A frequency spectrum showing levels in octave band widths.


Page 13

Percentile sound level: The sound level that is exceeded for a certain percentage of the time over a

measurement period. The background noise level is expressed in some standards as LA90, the A-

weighted sound level exceeded for 90% (almost all) of the time; Traffic is often assessed using the

index LA10, the sound level exceeded for 10% (not much) of the time.

Rating level: The equivalent continuous A-weighted sound level produced by a specific source, during

a specified time period, with an adjustment (correction) for the character of the sound – LAeqT (see

“specific noise level”).

Receiver: A person(s), property or equipment that is affected by noise.

Residual noise: The ambient noise remaining at a given position in a given situation when the specific

noise source under investigation is not present or is suppressed (see “background noise level”).

Single event level (sound exposure level): The total sound energy within a transient event, such as an

aircraft flyover, normalised into one second. May be used as a building block in the determination of

an LAeqT level for any number of events (n) and any total time period (T) described in seconds (t)

using the formula LAeqT = SEL + 10 logarithm n – 10 logarithm t (e.g. 20 trains an hour at an SEL of

90 dB(A) equate to an LAeq1hr of 90 + 10 log 20 – 10 log 3600 = 90 + 13 – 36 = 67 dB (A)).

Sound: A physical disturbance of a medium (e.g. air) that is capable of being detected by the human

ear.

Sound (pressure) level: Ten times the logarithm of the square of the ratio of the instantaneous sound

pressure to the reference sound pressure of 20 micropascals (µPa). Unit is the decibel (dB).

Sound level meter: An instrument that is used to measure sound (pressure) level, with standard

frequency and time-averaging weightings.

Sound spectrum: A representation of the magnitude of the components of a sound as a function of

frequency.

Specific noise level: The equivalent continuous A-weighted sound level produced by a specific

source, during a specified time period – LAeqT (see “rating level”).

Spherical propagation: Propagation into a sphere (as with an aircraft in the air). In practice sound

sources are located on the ground and so propagation is hemispherical.

Appendix A

Aerial view of site

Nor

th

Appendix B

Site layout plan

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This Plan includes the following Licensed Data: OS MasterMap Black and White PDF Location Plan by theOrdnance Survey National Geographic Database and incorporating surveyed revision available at the date ofproduction. Reproduction in whole or in part is prohibited without the prior permission of Ordnance Survey. Therepresentation of a road, track or path is no evidence of a right of way. The representation of features, as lines isno evidence of a property boundary. © Crown copyright and database rights, 2015. Ordnance Survey0100031673

Prepared by: Ella Murfet, 03-12-2015

0m 50m 100m 150m 200m 250m

Scale: 1:2500, paper size: A3

Location Plan

Appendix C

Computer model results without earth mounding

Appendix D

Survey details


[Page 1 of 2]

From: D F Sharps

Date: 6th September 2012

Subject: Noise survey - Blofield

Survey date: 5th September 2012.

Weather: 40% cloud cover; dry; 17 degrees Celsius; wind – very light (<2 metres/second)

from the north-west.

Equipment: Norsonics Sound Analysers, type 140. Calibrator type 1251. Tripods.

Calibration: Calibration certificates available. Systems calibrated before and after survey

with no drift in calibration level recorded.

Survey by: D F Sharps.

Survey locations: Along the footpath which is illustrated on the attached aerial view. Survey height

= 1.5 metres a.g.l.

Results: See Table 1, below, for CRTN Shortened measurement survey results (@ 10

metres from A47 kerb):

Table 1 CRTN survey results

Survey period (hrs) LA10 (dB) LAeqT (dB) LA90 (dB) LAMAX (dB)

1300 to 1400 80.2 76.4 66.9 84.1

1400 to 1500 78.7 74.6 66.0 82.9

1500 to 1600 79.0 75.1 65.8 83.3


[Page 2 of 2]

Average 79.3

Results: See Table 2, below, for survey results further into the appeal site:

Table 2 Survey results at different locations across the appeal site.

Survey period (hrs)Survey location – distance

from A47 kerb (metres)Ref location LA10 (dB) LAeqT (dB)

1310 to 1320 36 1 67.4 64.5

1325 to 1335 66 2 64.3 62.2

1340 to 1350 96 3 61.9 60.0

1400 to 1410 126 4 59.1 57.3

1415 to 1425 36 1 75.9 63.9

1430 to 1435 66 2 64.8 62.3

1440 to 1450 96 3 62.7 59.4

1455 to 1505 126 4 58.4 57.1

Nor

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environmental noise assessment - proposed residential ... · 2.6 the “noise policy aims” of the...

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