acoustic associates sussex ltd planning application noise

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Vibration - Expert Witness Testimony - Noise at Work - Air Tightness Testing - Auditorium Acoustics

Acoustic Associates Sussex Ltd

Planning Application Noise Assessment Soundscape Assessment

Report by: Scott Castle BSc (Hons) CEnv, MCIEH PGDip: Acoustics MIOA Date: 07/02/2020 Project: J2865 Issue 2

Site: St Peters Place, Sompting. BN15 8SB Client: Hamilton Investments Limited

2019 Noise Assessment Acoustic Associates Sussex Ltd Site: St Peters Place, Sompting. BN15 8SB J2865 Issue 2 – 07/02/2020

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Contents

1 Introduction - 4 -

2 Context, Noise Criteria & Noise Assessment Methodology - 5 -

2.1 Context ...................................................................................................................................... - 5 -

2.2 Location .................................................................................................................................... - 5 -

2.3 Soundscape................................................................................................................................ - 6 -

2.4 Site Plans .................................................................................................................................. - 6 -

2.5 Noise Assessment Methodology ................................................................................................ - 7 -

2.6 Relevant Planning Policies ....................................................................................................... - 7 -

2.7 External Amenity Areas ............................................................................................................. - 9 -

3 Sound Survey Baseline Conditions & Results - 10 -

3.1 Background and Existing Noise Survey Details ...................................................................... - 11 -

3.2 Weather Conditions – Attended Measured Data ..................................................................... - 12 -

3.3 Roadside Assessment (Western Road) ..................................................................................... - 12 -

3.4 Railside Assessment ................................................................................................................ - 13 -

3.5 Short Term Measurements ...................................................................................................... - 13 -

4 Predicted Sound Levels - 14 -

5 Discussion - 18 -

5.1 ProPG 2017 – Site Specific Risk Assessment .......................................................................... - 18 -

5.2 ProPG 2017- Further Assessment ........................................................................................... - 19 -

6 Rigorous Calculations - 21 -

6.1 Daytime – Living Room Assessment ........................................................................................ - 21 -

6.2 Night Time – Bedroom Assessment ......................................................................................... - 22 -

7 Proposed Mitigation Measures - 23 -

7.1 Glazing .................................................................................................................................... - 23 -

7.2 Ventilation ............................................................................................................................... - 24 -

7.3 Uncertainty.............................................................................................................................. - 25 -

8 Conclusion - 25 -


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Tables and Figures Table 1: BS8233:2014 Criteria .......................................................................................... - 9 -

Table 2. WHO (1999) Criteria ............................................................................................ - 9 -

Table 3. Survey Data ...................................................................................................... - 11 -

Figure 1. Location Plan - 5 -

Figure 2. Site Location Plan and Elevation Proposals. - 6 -

Figure 3. Ground Floor Layout - 7 -

Figure 4. Long Term Survey Locations - 10 -

Figure 5. Short Term Monitoring - 10 -

Figure 6. Survey Locations - 11 -

Figure 7. Windspeeds for 3-hour survey location- 2nd August 2018 - 12 -

Figure 8. Measured Daytime and Night Time Assessment - 12 -

Figure 9. Likely Occurrences of LAmax of 45dB with an open window. - 12 -

Figure 10. Likely Occurrence of LAmax with upgraded and closed glazing (SRI 41) - 13 -

Figure 11. Measured Daytime and Night Time Assessment - 13 -

Figure 12. Likely Occurrences of LAmax of 45dB with an open window. - 13 -

Figure 13. Likely Occurrence of LAmax with upgraded and closed glazing (SRI 36) - 13 -

Figure 14. 3D Noise Modelling, Orientated North - 15 -

Figure 15. IMMI Noise Modelling - Contour Predictions - Daytime - 15 -

Figure 16. IMMI Noise Modelling - Contour Predictions – Night Time - 16 -

Figure 17. Predicted Living Room Areas - 17 -

Figure 18. Predicted Bedroom Areas - 17 -

Figure 19. ProPG 2017 - Site Specific Risk Assessment - 18 -

Figure 20. Corridor Areas Highlighted of Proposed New Build - 19 -

Figure 21. Living Area Windows on Western Facade Proposed to be Sealed. - 19 -

Figure 22. Rigorous Calculation for Daytime Living Area - 22 -

Figure 23. Rigorous Calculation for Night Time Bedroom - 23 -

Report by: Scott Castle BSc (Hons) CEnv, MCIEH PGDip: Acoustics MIOA Checked by: Peter Attwood BSc MSc MCIOB MIOA MIDiagE

Issue 1 24/01/2020 Original Issue

Issue 2 07/02/2020 Drawing Updates

This report has been prepared for the private and confidential use of Hamilton Investments Limited. This report has been prepared by Acoustic Associates Sussex Limited with all reasonable skill, care and diligence and presents information included within the scope agreed with the client. If any third party whatsoever comes into possession of this report, they rely on it at their own risk and Acoustic


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Associates Sussex Ltd accepts no duty or responsibility (Including in negligence) to any such third party


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1 Introduction

Acoustic Associates have been appointed to undertake an acoustic assessment to support a planning application for the introduction of 18 new residential flats at St Peters Place, Sompting.

The purpose of the assessment was as follows:

• Measure and assess existing noise levels

• Assess noise levels created by the road transport, railway line and adjacent industrial estate and determine impact on the application site.

Standards and guidance referenced for this assessment include:

• ISO9613 (Attenuation of sound during propagation outdoors) 1996

• National Planning Policy Framework (NPPF) 2019

• National Planning Policy Guidance (Noise) – Updated 22 July 2019

• World Health Organisation – Guidelines on Community Noise -1999

• BS8233:2014 - Guidance on Sound Insulation and Noise Reduction for Buildings.

• BS4142:2014-A1:2019 – Methods For Rating And Assessing Industrial And Commercial Sound.

• ProPG: Planning and Noise – Professional Practice Guidance on Planning and Noise, May 2017

A number of class 1 sound level meters were deployed across the site in August 2018 in both short term and longer-term measurements to ensure that the daytime and night time soundscape were sufficiently captured. Manned measurements were also made of sites and specific noise sources at the adjacent industrial estate units.

The findings of the sound survey and liaison with the client and architects led to a number of schemes designs with, principally, good acoustic design being the driver for the design of the final scheme to protect both the future occupants and also the sustainability of the adjacent industrial estate. The scheme design limits overlooking of the railway and the industrial estate and sees bedrooms located in more sheltered areas. Use of corridor spaces, limited overlooking and use of the building form in terms of screening have all been usefully employed to minimise exposure to sound levels.

The survey and report findings indicate that the requirements of BS8233:2014 and ProPG2017 are met with windows closed. In line with ProPG2017, and the initial site risk assessment, a full risk assessment has been carried out to review the scheme and the surrounding noise sources. Recommendations have been made in respect of both glazing (upgraded and secondary to allow the client a choice) and ventilation to ensure that the internal living and sleeping spaces meet BS8233:2014 and ProPG2017.

Whilst the external amenity areas are predicted to be slightly above the WHO requirements, it is noted that the Brooklands Pleasure Park is within minutes walking distance from the site where individuals have access to lower environmental noise levels and greater tranquillity.

Assuming the implementation of the recommendations in terms of glazing and/or ventilation, planning permission should not be refused or withheld on noise grounds.


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2 Context, Noise Criteria & Noise Assessment Methodology

2.1 Context

It is proposed to remove the existing car repair/MOT business and adjacent residential garages and introduce a three-storey scheme of residential flats at Ground, First and Second floors.

The site has been subject to previous acoustic assessment in 2018 and the design has evolved to include principles of good acoustic design in line with current acoustic and planning guidance (ProPg,2017).

2.2 Location

The application site is seen in context in Figure 1 below which is orientated North.

Figure 1. Location Plan

To the West of the site is Western road, which is elevated as vehicles travel up the gradient to cross the railway line and down the other side. The closest carriageway to the application site is the Southbound carriageway. Western Road links both the A259 and the A27.

To the East is a commercial industrial estate with two main buildings in close proximity, separated by only a 1.8m chain link fence. These are Taurus engineering to the North and Unit 9 (Wayside Workshops) to the South. Taurus Engineering is a sheet metal fabricator and has fork lift trucks, deliveries, a large metallic skip and carries out cutting activities with associated extraction during the cutting process.


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Unit 9, Wayside Workshops is comprised of separate units with a custom vehicle workshop at 9C which was heard using a rivet gun which was very noticeable and very noisy. Other units in close proximity also have fork lift trucks. It was noted also that there are a number of openings in both buildings which readily allow the escape of noise from internal activities.

It is understood that Units 9 and Taurus Engineering both have B2 planning permission for heavy industrial uses. Contact with Taurus engineering indicates that their uses are predominantly 06:00-16:30 hours.

To the immediate South of the application site is St Peters Place, established residential flats (two storey) with associated parking.

To the South West is Brooklands Pleasure Park which is easily reached within minutes of walking and would provide residents an element of tranquillity/quiet.

2.3 Soundscape

The soundscape at the application site is comprised of cutting activities from Taurus, the movement of fork lift trucks, deliveries to the industrial units, road traffic noise on Western Road and passing railway noise. Sounds from seagulls and overhead aviation noise including smaller planes at lower altitude as well as commercial airlines were also a part of the soundscape.

Larger/heavier vehicles were noted to exhibit a rattle as they crossed over the railway bridge on Western Road.

2.4 Site Plans

The site location plan is seen in Figure 2 below with East and West proposed elevations also shown.

Figure 2. Site Location Plan and Elevation Proposals.

It is relevant to note that the Eastern façade facing the Industrial estate has been specifically designed without any habitable spaces overlooking the estate and the living rooms placed onto the facades facing Western Road. Bedrooms have been included within the more sheltered spaces on the Western facades and limited fenestration overlooks the railway line running East to West on the site. The ground floor layout is presented in Figure 3 below.


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Figure 3. Ground Floor Layout

2.5 Noise Assessment Methodology

It is proposed to use recently obtained site data (August 2018) to populate noise modelling software (IMMI) which has been constructed to replicate the application site in terms of both sound sources as well as boundary conditions and additionally topography.

2.6 Relevant Planning Policies

A number of key pieces of planning policy exist which have driven the survey work and design of the new residential scheme. These include the following:

2.6.1 ProPG : Planning and Noise – Professional Practice Guidance on Planning and Noise

ProPG 2017 advocates throughout the document, the importance of good acoustic design being key at the outset of a project. ProPG also introduces a site-specific risk assessment to inform developers and decision makers on the level of risk associated with a site being developed. The guidance also discusses the assessments of bedrooms at night for LAMax

values with these not exceeding 45dB LAmax internally more than 10 times a night to ensure that restful sleep may occur.

2.6.2 NPPF 2019 – National Planning Policy Framework (Updated Feb 2019)

The National Planning Policy Framework (February 2019) defines the Government’s planning policies for England and how these are expected to be applied. It sets out the Government’s requirements for the planning system only to the extent that it is relevant, proportionate and necessary to do so.

The following paragraphs are relevant within NPPF Section 15 (Conserving and enhancing the natural environment) states the following:


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Paragraph 170(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.

Paragraph 180-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; and:

Paragraph 182 - Planning policies and decisions should ensure that new development can be integrated effectively with existing businesses and community facilities (such as places of worship, pubs, music venues and sports clubs). Existing businesses and facilities should not have unreasonable restrictions placed on them as a result of development permitted after they were established. Where the operation of an existing business or community facility could have a significant adverse effect on new development (including changes of use) in its vicinity, the applicant (or ‘agent of change’) should be required to provide suitable mitigation before the development has been completed.

Paragraph 182 is particularly relevant for the application, as it seeks to introduce residents into an already elevated soundscape. However, the importance of design in protecting the interests of the industrial estate and the amenity of the future residents is acknowledged and noted within the proposed layout.

It is also relevant to note that residential properties in the form of St Peters Place already exist to the South of the proposed development area (see Figure 1 above).

2.6.3 BS4142:2014-A1:2019- Methods for Rating and Assessing Industrial and Commercial Sound

Whilst BS4142:2014 is predominantly used for the assessment of new plant and/or commercial activities, Section 8.5 also includes the situation where residents or receptors are introduced into an already busy/noisy environment. Section 8.5 is detailed below and requires that the soundscape is properly assessed.

2.6.4 BS8233:2014 – Guidance on Sound Insulation and Noise Reduction for Buildings


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The relevant internal sound levels to be achieved in a new build property are seen in Table 4 of BS8233:2014 which provides the following guideline values:

Activity Location Time period of day

07:00-23:00 23:00-07:00

Resting Living Rooms 35dB LAeq,16hour -

Dining Dining Room/Area 40dB LAeq,16hour -

Sleeping (daytime resting) Bedroom 35dB LAeq,16hour 30dB LAeq,8hour

Table 1: BS8233:2014 Criteria

2.6.5 World Health Organisation Guidelines on Community Noise dated 1999

The target internal levels are based on guidelines laid out by the World Health Organisation (WHO) Guidance dated 1999 and are as follows: Please note the difference between LAeq and LAmax parameters.

Room Type Target Maximum Internal Level - LAeq dB(A)

Living rooms 35 (Daytime only)

Bedrooms 30 (Night)

Room Type Maximum Internal Level – LAmax dB(A)

Bedrooms 45 (not more than 10-15 times per Night)

Table 2. WHO (1999) Criteria

2.7 External Amenity Areas

With regard to outdoor amenity areas WHO(1999) states the following:

To protect the majority of people from being moderately annoyed during the daytime, the outdoor sound level from steady, continuous noise should not exceed 50dB(A) on balconies, terraces and in outdoor living areas.

To protect the majority of people from being seriously annoyed during the daytime, the outdoor sound level from steady, continuous noise should not exceed 55dB(A) on balconies, terraces and in outdoor living areas.

It is noted that there are likely to be balconies on the living room areas at ground, first and second floors, however due to the complexity of noise modelling, these will not have been modelled. A communal external amenity space is also proposed at the North of the site between the building and the northern 2.4m acoustic fence.

BS8233:2014 (7.7.3.2) also makes reference to balconies and states as follows:

“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.

Other locations, such as balconies, roof gardens and terraces, are also important in residential buildings where normal external amenity space might be limited or not available, i.e. in flats, apartment blocks, etc. In these locations, specification of noise limits is not necessarily


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appropriate. Small balconies may be included for uses such as drying washing or growing pot plants, and noise limits should not be necessary for these uses.”

3 Sound Survey Baseline Conditions & Results

A sound survey was carried between the 2nd and 9th August 2018 using a number of class one sound level meters to assess the soundscape using both short and longer term surveys. Two longer term simultaneous locations were selected to measure sound levels that would impact the site. These included the roadside from Western Road in front of St Peters Place and at the Northern site perimeter where the railway tracks are located.

Short term measurements of train passes and of road traffic noise measured from the flat roof of the garages were also carried out on 2nd August 2018. The benefit of longer-term locations was to be able to measure night time sound levels and be aware of LAmax values and how these might impact bedrooms on the building. The long-term monitoring locations can be seen in Figure 4 below and the short-term measurement locations shown in Figure 5 below.

Figure 4. Long Term Survey Locations

Figure 5. Short Term Monitoring


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The positioning of the sound level meters in relation to the site are presented in Figure 6 below.

Figure 6. Survey Locations

Attended measurements were also made on the adjacent industrial estate on 6th August 2018 in order to be able to populate a noise model and understand the relevant sound sources.

3.1 Background and Existing Noise Survey Details

The meters, dates, heights, grid references and positioning in terms of context are presented in Table 3 below.

Table 3. Survey Data

All sound level meters were calibrated before and after commencing the noise measurements (@94dB no drift). All measurements for the dataset were taken with the time base set to 5 minutes.

Sound Level Meter Duration Status Date Location Grid Reference Height Distances

Norsonic 118 Class 13 hours Attended

02/08/2018

Tripod Mounted

on Garage Roof TQ17027/039754.1m 5.5m from roadside

Norsonic 118 Class 13 hours Attended

02/08/2018

Middle of Car

Park TQ17024/040142m

21m from railway track

edge

Norsonic 118 Class 1

Short

ReadingsAttended

06/08/2018 Industrial Estate Various 1.5m Close to Measurements

Svantek Castle Mirus3 days Unattended

06/08/18-09/08/18

Adjacent to

Western Road TQ17029/039621.8m 3.1m from roadside

01dB SIP95/Castle

3 days Unattended

06/08/18-09/08/18

Adjacent to chai

link fence at

Northern

boundary TQ17004/04022

2.5m10m from railway track

edge


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3.2 Weather Conditions – Attended Measured Data

The weather conditions for the attended monitoring are shown in Figure 7 below detailing that the wind speeds were appropriate for environmental monitoring. The temperatures ranged from 22.4°C to 24.9°C.

Figure 7. Windspeeds for 3-hour survey location- 2nd August 2018

3.3 Roadside Assessment (Western Road)

The assessment position, as shown in Figure 6 above was only 3.1m from the highway edge. The closest facades on the application site to the highway measure over 11m in distance.

Figure 8. Measured Daytime and Night Time Assessment

Figure 9. Likely Occurrences of LAmax of 45dB with an open window.

Day 1 71.4 Night 1 64.0

Day 2 71.8 Night 2 64.9

Night 3 65.4

Arithmetic

Average71.6 Arithmetic Average 64.8

Western Road - Roadside

Logarithmically Averaged Day and Night time Periods

LAeq, 16 hour- 07:00-23:00 LAeq, 8 hour 23:00-07:00

Night 1 Night 2 Night 3

86 87 89

No. of Occurrences of LAmax between 23:00-

07:00 hours above 45dB LAMax (SRI-15)


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Figure 10. Likely Occurrence of LAmax with upgraded and closed glazing (SRI 41)

3.4 Railside Assessment

As with the roadside assessment above, the measurements were made approximately 10m from the railway line at the northern most possible site. The closest property façade to the railway line is approximately 19m in distance.

Figure 11. Measured Daytime and Night Time Assessment

Figure 12. Likely Occurrences of LAmax of 45dB with an open window.

Figure 13. Likely Occurrence of LAmax with upgraded and closed glazing (SRI 36)

3.5 Short Term Measurements

The short-term measurements made, were confirmed by the longer-term surveys. The arithmetic average of the L10 for three consecutive hours recorded on the garage roof was recorded as 73.6 dB LA10. This is translated to LA10,18 hour by the subtraction of 1 dB and to LAeq,

16-hour by the subtraction of an additional 2dB. The 16-hour measurement predicted via a shortened survey on the garage roof was therefore 70.6 dB LAeq, 16 hour, compared with the measured 71.6 dB showing a 1dB difference, albeit measured approximately 15m apart (North to South – See Figure 6 above). As previously stated, short term measurements were also made on the industrial estate on 6 August 2018 to ensure that the soundscape was fully understood.


6 7 5



Day 1 61.9 Night 1 56.5

Day 2 62.1 Night 2 56.5

Night 3 56.4

Arithmetic

Average62.0 Arithmetic Average 56.5

Northern Site Perimeter - Railside

Logarithmically Averaged Day and Night time Periods

LAeq, 16 hour- 07:00-23:00 LAeq, 8 hour 23:00-07:00


54 64 62




6 7 5




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4 Predicted Sound Levels

As stated, IMMI noise modelling software has been used to predict the likely freefield sound pressure levels incident on the proposed site.

With sound levels accurately collected from the North and West and East of the site, a noise model may be constructed to determine how sound is likely to propagate across the application site and at different heights, which is key as Western Road is elevated.

The IMMI (Wolfel, 2015) noise modelling software is useful as it applies and faithfully replicates the methodology in ISO9613 for sound propagation. Road traffic noise and railway noise remain the major contributors to the site soundscape and have been included within the modelling.

The model was constructed using proposed plans and by plotting receptor positions at the locations where windows are being proposed, using drawing numbers 100 and 101 dated 29.10.18. Receptor positions replicated windows of both living rooms and bedrooms at ground, first and second floors.

Given that IMMI predicts freefield results, rather than add 3dB for the interaction of a sound pressure wave incident against a façade, a 12dB reduction has been made for an open window and a 30dB reduction allowed for a closed window, with the assumption of using standard thermal double glazing. These are both 3dB less than values detailed in BS8233:2014 for the reduction in sound pressure levels from outside to inside with both an open and closed window, when set in a brick façade.

The IMMI noise modelling software was calibrated by first creating a model with the existing properties to the South and West, with the survey positions plotted. Attended monitoring from the adjacent industrial estate was also included within the modelling set to a worst-case scenario as sounds were heard to occur simultaneously whilst present on the site. The sound sources in the model, ie the two-line sources (representing Western Road and the railway line) were then adjusted until the predicted sound pressure levels (measured in dB(A)) met those figures recorded in Figures 8 and 11 above. The proposed 2.4m acoustic fence on the Eastern and Northern site boundary has also been included within the model.

The contours of the noise model have been set to a 0.5m grid to show as accurately as possible the effects of sound upon the built environment. A 3D image is presented below of the proposed new build scheme, along with the neighbouring buildings.


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Figure 14. 3D Noise Modelling, Orientated North

Figure 15. IMMI Noise Modelling - Contour Predictions - Daytime


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Figure 16. IMMI Noise Modelling - Contour Predictions – Night Time

The predictions generated by the IMMI noise modelling software are shown in Figures 17 and 18 below. The red shaded cells represent where the internal sound levels exceed the criteria of BS8233:2014. The grey shaded cells shown on the living room areas relate to the fact that living rooms are not assessed for night time standards and relate to the daytime only.


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Figure 17. Predicted Living Room Areas

Figure 18. Predicted Bedroom Areas

Day NightWindow

Open

Window

Closed

Window

Open

Window

Closed

GF-Plot 1 Live 56 48.7 44 26 36.7 18.7

GF-Plot 2 Live 58.1 51 46.1 28.1 39 21

GF Plot 2-Live 56.6 49.4 44.6 26.6 37.4 19.4

GF-PLot 3 Live 56.1 48.6 44.1 26.1 36.6 18.6

GF-Plot 3 Live 2 59.5 52.3 47.5 29.5 40.3 22.3

GF-Plot 4 Live 55.9 48.2 43.9 25.9 36.2 18.2

GF-Plot 5 Live 58.3 50.7 46.3 28.3 38.7 20.7

GF-Live-plot 5 61.2 53.9 49.2 31.2 41.9 23.9

FF-Plot 8 Live 62.3 55.3 50.3 32.3 43.3 25.3

FF Plot 8-Live 60.1 53 48.1 30.1 41 23

FF-Plot 7 Live 58.4 51.2 46.4 28.4 39.2 21.2

FF-PLot 9 Live 58 50.7 46 28 38.7 20.7

FF-Plot 9 Live 2 62.3 55.2 50.3 32.3 43.2 25.2

FF-Plot 10 Live 58.6 51.3 46.6 28.6 39.3 21.3

FF-Plot 11 Live 61.1 53.9 49.1 31.1 41.9 23.9

FF-Plot 11-live 2 64.1 56.9 52.1 34.1 44.9 26.9

SF-Plot 17-live 2 68 61 56 38 49 31

SF-Plot 17 Live 64.5 57.4 52.5 34.5 45.4 27.4

SF-Plot 16 Live 61 53.8 49 31 41.8 23.8

SF-Plot 15 Live 2 64.6 57.5 52.6 34.6 45.5 27.5

SF-PLot 15 Live 60.2 53 48.2 30.2 41 23

SF-Plot 13 Live 59.6 52.4 47.6 29.6 40.4 22.4

SF Plot 14-Live 62.5 55.4 50.5 32.5 43.4 25.4

SF-Plot 14 Live 64.5 57.6 52.5 34.5 45.6 27.6

Day NightPredicted Freefield

Sound LevelsAccomodation

Description

Day NightWindow

Open

Window

Closed

Window

Open

Window

Closed

GF-Plot 1 bed 56.2 48.9 44.2 26.2 36.9 18.9

GF-Plot 2 bed 56.6 49.3 44.6 26.6 37.3 19.3

GF-Plot 3 Bed 56.5 49 44.5 26.5 37 19

GF-Plot 4-Bed 56.5 48.7 44.5 26.5 36.7 18.7

GF-Plot 5 Bed 58 50.2 46 28 38.2 20.2

GF-Plot 6 Bed 57.7 49.7 45.7 27.7 37.7 19.7

FF-Plot 7 Bed 58.3 51.1 46.3 28.3 39.1 21.1

FF-Plot 8 bed 56.6 49.3 44.6 26.6 37.3 19.3

FF-Plot 9 Bed 58.2 50.9 46.2 28.2 38.9 20.9

FF-Plot 10-Bed 58.5 51.1 46.5 28.5 39.1 21.1

FF-Plot 11 Bed 60 52.5 48 30 40.5 22.5

FF-Plot 12 Bed 59.4 51.8 47.4 29.4 39.8 21.8

SF-Plot 13 Bed 59.4 52.2 47.4 29.4 40.2 22.2

SF-Plot 14 bed 60.9 53.8 48.9 30.9 41.8 23.8

SF-Plot 15 Bed 59.8 52.6 47.8 29.8 40.6 22.6

SF-Plot 16-Bed 60.4 53.1 48.4 30.4 41.1 23.1

SF-Plot 18 Bed 61.1 53.8 49.1 31.1 41.8 23.8

SF-Plot 17 Bed 63.1 55.8 51.1 33.1 43.8 25.8

Day NightAccomodation

Description

Predicted Freefield

Sound Levels


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5 Discussion

As stated, the proposed current site layout has been driven by discussions with the client, their architect and Acoustic Associates Sussex Limited. A previous scheme was reviewed with recommendations made to the client in respect of where to place habitable rooms to ensure that future occupants remain protected from the industrial estate and vice versa.

5.1 ProPG 2017 – Site Specific Risk Assessment

As stated, as a new residential site, there is a need to provide a risk assessment for the decision makers and the client.

The risk assessment is shown below and indicates that the site is high risk, and that a full assessment will be required to demonstrate how good acoustic design has been worked into the site development process.

It should be noted that the drivers for the site being high risk are the measured survey data, not necessarily, the predicted sound levels for the proposed development, which are made using the noise modelling software and are shown in Figures 17 and 18 above.

Figure 19. ProPG 2017 - Site Specific Risk Assessment

Site: St Peters, Lancing. BN15 8RZ

Date: 6th August 2018

Individual Scott Castle

Proposal Proposed Residential Flats

Survey or Prediction Survey and Prediction

Freefield Survey

Instrumentation used 2x Castle Mirus, 1x Norsonic 118

Typical/Worst case 24 hour period

Location Assessed(Grid Ref) TQ 17024/04014

Subjective Noise sources at site Road and Rail traffic noise only.Ind Est Excluded

Weather conditions Dry and hot

Daytime (LAeq, 16 hour) 72/62 dB LAeq,16 hour (Roadside/Railside)

Night (LAeq, 8 hour) 65/56 dB LAeq, 8 hour (Roadside/Railside)

Night LAMax Events above 45dB(A) Roadside(15Rw)-89 events/Railside(15Rw)-62

Level of Risk Posed High

Stage 2 Full Assessment Yes

Signed Off by Peter Attwood

Date 15.1.2020

Next Steps

Outcome

Result

Stage 1. Initial Site Risk Assessment

No Mitigation Measures


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5.2 ProPG 2017- Further Assessment

Given that further assessment is necessary, the following headings are applicable,

• Element 1. Good Acoustic Design Process

The source noises are those likely to be from passing road traffic to the West, railway traffic to the North and the Industrial Estate to the East. Accordingly, the Eastern boundary has included a solid wall with a buffer corridor in which to access the flats. A corridor type approach has also been utilised for the Northern and Southern elevations with only bathroom windows placed onto the North and South facades.

The building footprint on the Eastern façade has also been extended further North to South to provide a buffer edge against the industrial estate with both car and bicycle parking proposed. The linear shape can be seen highlighted in Figure 20 below.

Figure 20. Corridor Areas Highlighted of Proposed New Build

Sealed windows are proposed on the Western elevation facing Western Road with ventilation possible through both the kitchen windows and/or the side opening door/window combinations, placed onto the more sheltered facades. The proposed sealed windows are shown in Figure 21 below. Whilst the windows are proposed to be sealed, consideration should be given to allowing the residents access to open these for cleaning purposes.

Figure 21. Living Area Windows on Western Facade Proposed to be Sealed.


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• Element 2. Internal Noise level guidelines

From the predicted noise modelling, standard thermal double glazing is likely to be satisfactory for most windows. However, the Western most living room areas, which are proposed to have their façade windows sealed, are likely to require upgraded glazing. The internal sound level criteria is only met with windows closed. Please note the comments above regarding sealed windows and whether these might negate the requirements for future residents being able to clean the windows.

With upgraded glazing and alternative ventilation, the required noise levels in BS8233:2014 and ProPG2017 are capable of being met for both a daytime and night time criteria.

• Element 3. External Amenity Area Assessment

It is noted that there is a communal garden area located at the North end of the building, sheltered between the building and the 2.4m acoustic fence line to separate the railway. The noise model suggests a LAeq,16 hour of 57.1dB which is over the WHO requirement for the onset of serious annoyance.

In line with the National Planning Policy Guidance- Noise which was updated on 22 July 2019, it is stated that noise impacts may be partially offset if residents have access to a relatively quiet, protected publicly accessible amenity space that is within 5 minutes walking distance. It is noted that the Brookland’s Pleasure Park is directly across Western Road and within 5 minutes walking time.

• Element 4. Assessment of other relevant issues

Element 4 may be broken down into the following headings with relevant narrative applied.

• Compliance with relevant national and local policy

As discussed above, BS8233:2014 applies to continuous and anonymous noise such as transportation noise (road and railway).

With regards to the National Planning Policy Framework 2019 (discussed above in 2.6.2), and specifically paragraphs 109 and 123, it is considered that sufficient design principles have been included to both protect the future residents of the dwelling but also that consideration has been given to protecting the existing commercial/industrial uses. Whilst the NPPF and the “Agent of Change principle” both provide narrative on not having “unreasonable restrictions placed on their businesses” and “preventing new and existing developments from contributing to or being put at unacceptable risk from or being adversely affected by unaccepted levels of noise pollution”, this has been considered and mitigated against.

In line with the Planning Noise Advice Document – Sussex dated 2015, the report has considered and assessed the sounds being generated by both the transport sources and the adjacent industrial estate when considering new noise sensitive developments. Specifically, as per section 5.6, consideration has also been given to new noise sensitive developments near to existing industrial and commercial noise sources.


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• Magnitude and extent of compliance with ProPG

It is considered that the requirements of the LAmax events and good acoustic design contained within ProPG2017 have been met by the architects considering acoustics from an early stage.

• Likely occupants of the development

The proposed tenure of the scheme is not yet known. Whilst it will not be possible to open windows due to the noise climate, future residents have the ultimate choice about whether and when to open windows.

• Acoustic design v unintended adverse consequences

The design proposals for St Peters Place do not contain any visual barriers, sealed facades or remove views for the future residents. The design has specifically orientated bedroom facades away from the noisier areas and the use of corridor spaces as an additional buffer for any sounds generated from the industrial estate to the East. Future occupants as stated above have personal control over their connection with the local environment.

• Acoustic design v wider planning objectives

The enhanced glazing (where appropriate), ventilation and design and orientation of habitable spaces, make St Peters Place work as a new build residential scheme with good acoustic design from the project inception.

6 Rigorous Calculations

Two rigorous calculations in line with section G.2 of BS8233:2014 have been carried out to assess the highest predicted living area for the daytime and the highest predicted bedroom area for the night time period to ensure that proposed mitigation measures are sufficient.

The rigorous calculation process, rather than using a simplistic outside to inside subtraction, considers the ratio of exposed brickwork, glazing and spaces that sound energy are able to pass through to enter an inside living space. As second floor apartments, the exposed roof space is also considered as a medium by which sound energy may penetrate the rooms.

The calculation examines the performance of different glazing combined with the ventilation method to provide an overall Sound Reduction Index as well as the predicted internal sound level.

6.1 Daytime – Living Room Assessment

Plot 17, Living Room (second floor) area has been assessed as the highest predicted daytime value of 68dB, freefield. The calculation has been completed by combining all glazed spaces from the two kitchen windows as well as the Northern façade access to the balcony area.

The rigorous calculation for Plot 17 Living Room area (see Figure 22 below), which is West facing concludes that the requirements of BS8233:2014 are met in that internal sound levels are met with 34 dB LAeq, 16 hour. This may be achieved using secondary glazing of 6/100/4 or alternatively, upgraded glazing of 10/12/6.4.


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Figure 22. Rigorous Calculation for Daytime Living Area

6.2 Night Time – Bedroom Assessment

As stated above, it was referenced that for the night time period, the drivers for the glazing and/or ventilation mitigation measures will use both the outside LAeq, 8 hour and additionally the LAmax values. It was noted for the highest predicted bedroom, plot 17 (second floor) that the predicted sound pressure level was 56dB LAeq,8 hour and accordingly, will require an SRI of 32dB.

The rigorous calculation for Plot 17 bedroom (see Figure 23 below), which is North facing concludes that both the requirements of BS8233:2014 are met in that internal sound levels are below 30dB LAeq, 8 hour and additionally that the requirements of ProPG2017 are met in that the SRI of 32dB is exceeded.

Term Derivation Value Rwi Sound Reduction of Window (Octave)

Ao Given in BS EN 20140-10 = 10 (m^2) 10 Rew Sound Reduction Index of External Wall (Octave)

Sf Total Facade Area (m^2) 42.896 Rrr Sound Reduction Index of Roof/Ceiling (Octave)

Swi Window Area (m^2) 6.285 A Equivalent Absorbtion Area of Rx Room

Sew External Wall Area (m^2) 36.611 Dn,e Insulation of Trickle Vent (BS EN 20140-10)

Srr Ceiling Area (m^2) 30.22S Total Area sound enters the room (m^2) 66.831

Octave Band Centre Frequency

125 250 500 1000 2000 4000

Leq,ff Free-Field External Noise Level 70 66 64 64 61 54

Dn,e 2500EA 41.7 39.6 37.2 45.3 52.6 54.9

Rwi 6_100_4 26 34 44 56 53 52

Rew

Cavity Masonry (Brick Cavity with Insulation

lightweight block) 41 39 44 52 60 65

Rrr 100mm flat concrete roof (230 kg/m2) 52 52 52 52 52 52

A

Equivalent Absorbtion Area of Room (Copied from

BS8233) 11.00 14.00 16.00 16.00 15.00 15.00

125 250 500 1000 2000 4000

70 66 64 64 61 54

1.012E-05 1.64E-05 2.85E-05 4.41593E-06 8.22284E-07 4.84197E-07

0.0002362 3.74E-05 3.74E-06 2.36226E-07 4.71332E-07 5.93372E-07

4.351E-05 6.9E-05 2.18E-05 3.45648E-06 5.47815E-07 1.73234E-07

2.853E-06 2.85E-06 2.85E-06 2.8531E-06 2.8531E-06 2.8531E-06

10.835853 9.788499 9.20858 9.208579769 9.488867005 9.488867005

45.500223 36.78064 30.76104 23.60736991 17.20478653 9.62083499

-16.1 -8.6 -3.2 0 1.2 1

29.400223 28.18064 27.56104 23.60736991 18.40478653 10.62083499

68

34

34

Key for Table Below

A-Weigted Level Outside

A-Weighting

DescriptionTerm

Frequency Dependent Variables

Non Frequency Dependent Variables

Swi/S . 10^(-Rwi/10)

Sew/S . 10^(-Rew/10)

A-Weighted Leq

Term From Equation Below

Leq,2


BS8233 Calculation Details

Leq,ff

Ao/S . 10^(-Dn,e/10)

BS8233 Predicted Internal A-Weigted Level

Prediced Building Envelope SRI

Srr/S . 10^(-Rrr/10)

10log10(S/A)+3


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Figure 23. Rigorous Calculation for Night Time Bedroom

7 Proposed Mitigation Measures

As stated above, the residential scheme will meet internal sound levels, as required in BS8233:2014 and ProPG2017(bedrooms only) by having closed windows.

7.1 Glazing

Windows for the majority of the scheme are capable of using standard thermal double glazing. A standard thermal double-glazed unit (4/12/4) when set in a masonry façade will provide an Rw of 33dB (BS8233:2014 – G.2)

Where windows are proposed for the 9 living room facades closest to Western Road, it is noted that there is a proposal to have these windows sealed shut. Whilst the proposal is noted to having the principle of sealed windows, future residents may require access for window cleaning purposes and retain the freedom to open such windows. This should not present any concern, as there are windows/doors either side of the living room facades to the living spaces which are capable of being opened. Notwithstanding this, the living room facades closest to

Term Derivation Value Rwi Sound Reduction of Window (Octave)

Ao Given in BS EN 20140-10 = 10 (m^2) 10 Rew Sound Reduction Index of External Wall (Octave)

Sf Total Facade Area (m^2) 8.68 Rrr Sound Reduction Index of Roof/Ceiling (Octave)

Swi Window Area (m^2) 1.82 A Equivalent Absorbtion Area of Rx Room

Sew External Wall Area (m^2) 6.86 Dn,e Insulation of Trickle Vent (BS EN 20140-10)

Srr Ceiling Area (m^2) 15.08S Total Area sound enters the room (m^2) 23.76


125 250 500 1000 2000 4000

Leq,ff Free-Field External Noise Level 58 54 52 52 49 42

Dn,e 2500 Greenwood EA 41.7 39.6 37.2 45.3 52.6 54.9

Rwi 4_12_4 24 20 25 35 38 35

Rew

Cavity Masonry (Brick Cavity with Insulation

lightweight block) 41 39 44 52 60 65

Rrr 100mm flat concrete roof (230 kg/m2) 52 52 52 52 52 52

A

Equivalent Absorbtion Area of Room (Copied from

BS8233) 11.00 14.00 16.00 16.00 15.00 15.00

125 250 500 1000 2000 4000

58 54 52 52 49 42

2.845E-05 4.61E-05 8.02E-05 1.24209E-05 2.31288E-06 1.36193E-06

0.0003049 0.000766 0.000242 2.42228E-05 1.21402E-05 2.42228E-05

2.293E-05 3.63E-05 1.15E-05 1.8217E-06 2.88721E-07 9.13015E-08

4.005E-06 4E-06 4E-06 4.00456E-06 4.00456E-06 4.00456E-06

6.3445375 5.297184 4.717265 4.717264537 4.997551773 4.997551773

29.911669 28.6041 22.00545 12.99808843 6.726716449 1.722281821

-16.1 -8.6 -3.2 0 1.2 1

13.811669 20.0041 18.80545 12.99808843 7.926716449 2.722281821

56

24

33


BS8233 Calculation Details

Leq,ff

Ao/S . 10^(-Dn,e/10)

BS8233 Predicted Internal A-Weigted Level

Prediced Building Envelope SRI

Srr/S . 10^(-Rrr/10)

10log10(S/A)+3

Key for Table Below

A-Weigted Level Outside

A-Weighting

DescriptionTerm

Frequency Dependent Variables

Non Frequency Dependent Variables

Swi/S . 10^(-Rwi/10)

Sew/S . 10^(-Rew/10)

A-Weighted Leq

Term From Equation Below

Leq,2


- - 24 - -

Western Road will require enhanced glazing and may utilise secondary glazing with a configuration of 6/100/4.

It is also relevant to note that there are a number of drivers which will dictate the specification for the glazing required. For the daytime and living areas, the external soundscape and specifically, the LAeq,16 hour will drive the required level of protection. However, for bedrooms, at night, both the LAeq,8 hour and LAmax values occurring internally, will also drive the degree of protection needed for the residents.

Having considered the roadside survey, adjustments have been made to calculate the likely LAmax levels internally, when compared against the predicted freefield levels from the noise model. In this particular instance, the highest external freefield predicted sound level at night is 56 dB LAeq, 8 hour. Using this figure, the LAmax values have been calculated to determine that the sound reduction index needed for such a value is 32 dB. Accordingly, standard thermal double glazing of 4/12/4 will be sufficient for the closed windows to protect future occupants from night time noise. The freedom for residents to open windows is discussed further below in section 7.2.

Whilst there are proposals to have facades with sealed windows, consideration should be given to allowing the future residents the choice of being able to open windows for items such as cleaning and/or purge ventilation.

The resulting effect of not being able to open windows is that there is still a requirement to provide background ventilation of the habitable rooms.

It is noted that bathroom and corridor windows have not been plotted within the noise model, as these are likely to utilise standard thermal double glazing.

7.2 Ventilation

As stated above, the internal sound level criterion for habitable spaces will be exceeded with open windows. With windows closed, the internal requirements will be met, however there will still be a requirement to consider ventilation of the properties.

There are a number of ways of ventilating and providing fresh air into a property. When considering ventilation, there must be sufficient air changes but also compliance with the building regulations (Approved Document F). Any future strategy for ventilation should be subject to examination by an M+E ventilation engineer.

The options are as follows:

System 1 - Background ventilation using trickle vents

System 2 - Passive stack ventilation

System 3 - Continuous mechanical extraction ventilation (MEV)

System 4 - Mechanical Ventilation and Heat Recovery (MVHR)

Whilst residents have the freedom to open their windows, in doing so, the internal noise criterion are likely to be exceeded for some of the facades. However, for purge ventilation, it is important to note that noise criteria are not applicable. Purge ventilation is the process of allowing rapid turnover of air changes when for example one wishes to remove cooking odours or paint fumes from inside the property.

A rigorous calculation carried out for Plot 17, the second-floor flat living room close to Western road identifies that secondary glazing may be used with Greenwood 2500EA acoustic trickle vents (Dn,e,w(Ctr) of 42dB) to achieve the required internal sound levels in line with BS8233:2014.


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7.3 Uncertainty

The sound level meters used for the survey period were calibrated before and after the survey in situ, without any drift having occurred, to ensure that the information and data being obtained was representative and that the sound level meters were operating correctly.

It is relevant to note that there has not been any rounding of measured data throughout the calculation process to prevent duplication of process. The measured data is also noted to use only whole daytime or night time periods. The data presented for both roadside (West) and trackside (North) has been validated by short term surveys and is considered to be robust.

Whilst the noise model has used measured data collected during summer 2018, there is no reason to consider that the noise climate has changed.

Where it was recognised that there were obvious noise sources at the adjacent industrial estate, care was taken to ensure that these were measured and included within the noise modelling software.

The report has also considered the agent of change principle (s182, NPPF, 2019) in that there must be sufficient safeguards in place for the scheme design to protect both the future residents, but also the existing industrial/commercial estate to the East.

.

8 Conclusion

A number of class 1 sound level meters were deployed across the site in August 2018 in both short term and longer-term measurements to ensure that the daytime and night time soundscape were sufficiently captured. Manned measurements were also made of sites and specific noise sources at the adjacent industrial estate units.

The findings of the sound survey and liaison with the client and architects led to a number of schemes designs with, principally, good acoustic design being the driver for the design of the final scheme to protect both the future occupants and also the sustainability of the adjacent industrial estate. The scheme design limits overlooking of the railway and the industrial estate and sees bedrooms located in more sheltered areas. Use of corridor spaces, limited overlooking and use of the building form in terms of screening have all been usefully employed to minimise exposure to sound levels.

The survey and report findings indicate that the requirements of BS8233:2014 and ProPG2017 are met with windows closed. In line with ProPG2017, and the initial site risk assessment, a full risk assessment has been carried out to review the scheme and the surrounding noise sources. Recommendations have been made in respect of both glazing (upgraded and secondary to allow the client a choice) and ventilation to ensure that the internal living and sleeping spaces meet BS8233:2014 and ProPG2017.

Whilst the external amenity areas are predicted to be slightly above the WHO requirements, it is noted that the Brooklands Pleasure Park is within minutes walking distance from the site where individuals have access to lower environmental noise levels and greater tranquillity.

Assuming the implementation of the recommendations in terms of glazing and/or ventilation, planning permission should not be refused or withheld on noise grounds.

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