ST. MODWEN

PROPOSED RESIDENTIAL DEVELOPMENT

FINSLEY GATE, BURNLEY

NOISE ASSESSMENT

29 July 2013

AEC REPORT: P2803/R1/BT

Prepared by:

Prepared by: Ben Tomlin

BSc(Hons), MIOA

Acoustic & Engineering Consultants Limited

Lockside 1 Stockport Road Marple Stockport Cheshire SK6 6BD Telephone 0161 449 5900 Fax 0161 449 5901

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CONTENTS

Page

1.0 INTRODUCTION 3

2.0 SITE DESCRIPITION 3

3.0 NOISE MEASUREMENTS 3

4.0 BASIS OF ASSESSMENT 4

5.0 ASSESSMENT OF PROPOSED DEVELOPMENT 6

6.0 CONCLUSIONS 6

FIGURE 1 –Site Location Plan Identifying Measurement Locations FIGURE 2 –Proposed Site Layout

APPENDIX A – Acoustic Terminology in Brief

APPENDIX B – Measurement Procedure

DOCUMENT STATUS

Revision Date Document Details Author Checked

By

Original 29 July 2013 Original

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1.0 INTRODUCTION

1.1 Acoustic & Engineering Consultants Limited (AEC) has been appointed by St Modwen Properties PLC, to undertake a noise assessment in relation to a new residential development on Finsley Gate, Burnley.

1.2 This report details the ambient noise levels measured on site and discusses the implications on

the external building fabric to achieve acceptable internal noise levels to meet appropriate requirements. This noise assessment is required to accompany the associated planning application for the development.

1.3 The proposed scheme involves the development of 12 houses, and a number of flats, with ground floor leisure use, on the site of a former mill at Finsley Gate in Burnley. A site location plan is shown on Figure 1, and a plan of the proposed development is identified on Figure 2.

1.4 The houses are new build, while the apartments are to be formed within the refurbished mill. At

ground floor level in the mill, it is understood that a pub/restaurant type facility may be provided, and hence an assessment of the required sound insulation performance of the separating floor has also been made.

1.5 Contact was made with Edward Taylor, an Environmental Health Officer at Burnley Council (BC),

in relation to the potential noise issues at the site. From these discussions, it was confirmed that the main noise sources potentially affecting the site were road traffic on Finsley Gate, deliveries to the Tesco Store opposite the site, and industrial noise from the industrial units to the south. During this consultation, the periods of noise measurement were also agreed.

1.6 Acoustic terminology is described in brief in Appendix A.

2.0 SITE DESCRIPTION 2.1 The site is located on Finsley Gate, beyond which, to the North, is a large Tesco superstore and

what appeared to be a disused bowling alley. 2.2 The Leeds and Liverpool Canal is located to the South and East of the site, and to the west of the

site lies a disused shop, with car parking beyond. 2.3 Beyond the canal to the South is a large area of waste ground, with a number of vehicle repair

units beyond, the closest of which is around 150m from the nearest potentially affected house.

3.0 NOISE MEASUREMENTS 3.1 Daytime noise levels were measured by AEC on Wednesday 10 July 2013, between 1030h to

1330h, and in accordance with the shortened measurement procedure in Calculation of Road Traffic Noise (CRTN). Night-time noise levels were measured between 0530h and 0700h on Friday 19 July 2013, after discussion with Edward Taylor at Burnley Borough Council (BC). Full details of the noise surveys are presented in Appendix B, with a brief description provided below.

3.2 Noise levels were measured at four locations around the site. Locations A and B, as identified on

Figure 1, were selected to measure road traffic noise affecting the northern elevation of the properties.

3.3 Location C was selected to measure noise affecting the southern elevations of the properties. 3.4 Location D was chosen to measure noise from the vehicle repair garages and industrial units on

Marlborough Street.

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3.5 The typical measured free-field daytime and night-time noise levels, measured at Locations A-D over 5 minute periods for these locations are detailed in Table 1 below.

Table 1 – Typical Measured Noise Levels

Location Period Ambient Noise

Level, dBLAeq

Maximum Noise

Level, dBLAmax

A Daytime 70-73 80-92

Night-Time 63-68 78-87

B Daytime 65-67 75-80

Night-Time 57-63* 70-76*

C Daytime 46-52 53-69

Night-Time 43-45 50-60

D Daytime 57-65 78-85

* Assumed, based on other measured data

3.6 Noise levels at all locations were dominated by road traffic on Finsley Gate, and distant traffic. At

location C, birdsong and the occasional barge pass-by affected the noise levels. 3.7 The night-time period was chosen as 0530h-0900h, as the EHO had concerns relating to

deliveries at the Tesco store opposite. The noise levels of a number of deliveries were measured, but were not found to be significantly different to noise levels when no deliveries occurred.

3.8 Noise levels were very consistent at all locations. 3.9 Noise levels were also measured at location D, opposite a number of car repair and industrial

units. During this period, a car was being worked on, and the industrial unit also took a delivery. However, it is important to note that the noise levels were dominated by road traffic on Marlborough Street.

4.0 BASIS OF ASSESSMENT 4.1 Following consultation with BC it is understood that the scheme should be designed in order that

the noise level limits detailed in the WHO document “Guidelines for Community Noise” are achieved.

4.2 The WHO document proposes guideline values for noise both inside and outside dwellings. These

are to achieve acceptable internal noise levels to avoid annoyance and sleep disturbance. Inside dwellings, the noise level should not exceed 30dBLAeq,8 hour and 45dBLAmax in bedrooms at night and 35dBLAeq, 16 hour in other habitable spaces during the day. These are generally in line with the guidance provided in BS8233 to achieve a good standard.

4.3 In addition, the WHO document also states that attenuation of external to internal noise levels

provided by a window partially open for ventilation is up to 15dB, which relates to allowable external levels of 50dBLAeq outside habitable rooms during the daytime, as well as 45dBLAeq and 60dBLAmax during the night-time.

4.4 The World Health Organisation’s (WHO) document ‘Guidelines for Community Noise’ document

proposes that noise levels should not exceed 55dBLAeq for external areas, to protect the majority of people from being seriously annoyed during the daytime.

4.5 With regards to the maximum noise level limit of 45dBLAmax during the night-time, WHO guidelines states that ‘for a good night’s sleep, it is believed that indoor sound pressure levels should not exceed approximately 45dBLAmax more than 10 to 15 times per night”. Based on this AEC would

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propose to design the façade in order that 45dBLAmax is not typically exceeded during the night-time period 2300h to 0700h. As such, there is currently no intention to control maximum noise levels from non-typical events such as occasional noisy motorcycle pass-bys or emergency service sirens.

5.0 ASSESSMENT OF PROPOSED DEVELOPMENT

Living Rooms during the daytime Finsley Gate Elevation 5.1 Living rooms, and other habitable spaces such as kitchen/dining rooms, should have internal

ambient noise levels of no higher than 35dBLAeq during the day.

5.1 At location A, the average level was 75dBLA10. Based on the shortened CRTN calculation method, this is equivalent to LA10,3hr. To convert this to a daytime average, LA10,18hr, 1dB is subtracted. To convert this to an ambient noise level, a further 2dB is subtracted, giving an overall level of 72dBLAeq,16hr, which is marginally higher than the average measured ambient noise level, dBLAeq, and hence the CRTN figure has been used in our calculations.

5.2 Based on the measured data and taking into account the distance attenuation, noise levels external to the properties on the Finsley Gate elevation would be in the region of 67dBLAeq. Therefore, windows would need to remain closed in order to achieve the required internal noise levels of WHO. Windows could be openable, but would need to be well sealed when closed. All frames and seals must not downgrade the acoustic performance of the glazing.

5.3 Calculations show that, assuming a window area of no greater than 33% of the wall area, the

glazing would need to achieve a minimum sound insulation performance of 38dBRw and 32dBRTRA, which could be achieved, for example, with 10mm-thermal cavity-6mm glass.

5.4 The above windows, in conjunction with ventilation having a minimum sound insulation

performance of 36dBDn,e,w, would achieve an internal noise level of 35dBLAeq or lower in all living areas facing onto Finsley Gate.

5.5 For the living rooms on the side of the mill, the specification could be reduced to standard thermal

glazing. Ventilation would need to achieve a minimum sound insulation performance of 31dBDn,e,w.

Canal Elevation 5.6 Noise levels on the canal path, equivalent to the rear of the properties, were in the order of

45-50dBLAeq, and, hence, ventilation to the living rooms at the rear of the houses could be provided by openable windows, and the required internal noise levels would be achieved.

5.7 Additionally, the external terraces to the rear of the building would therefore also have noise levels of around 45-50dBLAeq, significantly less than the required 55dBLAeq.

5.8 Measurements were also undertaken at location D, to investigate potential noise from the

industrial units to the south. However, although noise levels of around 60-65dBLAeq were measured at this location, the noise levels were dominated by road traffic on Marlborough Street, and as such, noise levels due to industry were significantly lower. It is also important to note that industrial activity was completely inaudible at measurement location C at all times.

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Bedrooms at night Finsley Gate Elevation

5.9 The worst case noise levels measured in the early morning were around 68dBLAeq and 84dBLAmax.

Therefore, it would be the maximum noise levels which dictate the sound insulation requirements for the external elevation.

5.10 Calculations were based on a maximum level of 84dBLAmax as a typical maximum level, based on ignoring the two highest maximums, which were due to HGV horns sounding, which seems reasonable based on the guidance in the WHO document, described in 4.5 above.

5.11 On this basis, calculations show that, assuming a window area of no greater than 33% of the wall

area, the glazing would need to achieve a minimum sound insulation performance of 38dBRw and 32dBRTRA, (e.g. 10mm-thermal cavity-6mm glass), and the ventilators would need to achieve a minimum sound insulation performance of 38dBDn,e,w, in order to achieve an internal noise level of 30dBLAeq and 45dBLAmax or lower in all bedrooms facing onto Finsley Gate.

5.12 At the rear of the properties, the highest measured noise level was around 45dBLAeq and

60dBLAmax. Therefore, although ventilation could potentially be provided via partially opened windows, internal noise levels may occasionally marginally exceed the desirable levels. As such, it may be prudent to provide alternative means of ventilation, which provides sound insulation in excess of around 20dBRw.

5.13 For the bedrooms on the side of the mill building, standard thermal glazing, with ventilation

achieving a minimum of 36dBDn,e,w.

5.14 Other building elements, such as the walls and roof, would need to achieve a sound insulation performance of 48dBRw or higher on the front elevation, or 40dBRw or higher at the rear. This is not an onerous specification.

Sound Insulation between ‘Pub’, and flats above.

5.15 At this stage, it is not clear what the actual use of the ground floor leisure unit may be. However,

since a pub is one of the proposed options, and is likely to be the most onerous, we have made an assessment based on possible pub usage.

5.16 In our experience, it is the maximum noise levels, rather than the average levels, which are generally considered the most intrusive.

5.17 Noise levels in a busy pub have been measured previously by AEC, and are typically in the region

of 90-100dBLAmax. This is not significantly affected by low level background music (generally due to shouting etc).

5.18 In our experience, a good specification for this type of noise to be reduced to in the bedrooms

above is NR25Lmax. This curve would take account of low frequency noise, as well as the overall noise level.

5.19 In order to achieve this level, based on music noise levels of around 95dBLAmax, calculations

indicate that the floor must provide a sound insulation performance of at least 65dBRw. This would be equivalent to a 150mm profiled concrete deck, with 2 layers of sound resistant plasterboard independently supported, or hung from an MF system, forming a cavity of at least 100mm, with mineral fibre in the cavity.

5.20 It should be noted that this does not comprise a detailed design review; just an initial assessment

to demonstrate that potentially, noise transfer from the pub can, potentially, be reduced to acceptable levels to the bedrooms above. A full detailed design process would need to be undertaken when more details are known.

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6.0 CONCLUSIONS

6.1 AEC has undertaken measurements around the proposed residential development at Finsley Gate Mill, Burnley, the time periods of which were based on discussions with Edward Taylor, an Environmental Health Officer with Burnley Borough Council.

6.2 The dominant noise source around the site was found to be due to road traffic on Finsley Gate.

Night time measurements included delivery noise from Tesco, however, it was deemed that levels from this source were significantly below the road traffic noise, which included significant numbers of HGV pass-bys. Noise due to deliveries and activities associated with the industrial units on Marlborough Street were also found to be inaudible at all noise sensitive locations at all times of day and night.

6.3 During the daytime period the ambient noise level at the location of the front facade of the

proposed properties would typically be 67dBLAeq. These levels drop to 60dBLAeq at night, with maximum noise levels of around 73-76dBLAmax incident upon the most affected bedrooms at night..

6.4 Burnley Borough Council requires that internal ambient noise levels should not exceed 35dBLAeq in

living rooms during the daytime and 30dBLAeq and 45dBLAmax in bedrooms at night. 6.5 Based on the measured noise levels, mitigation measures are required to control internal noise

levels in the habitable rooms and bedrooms overlooking Finsley Road, and suggestions have been made in this regards.

6.6 Externally, all terraced areas would be subject to noise levels significantly below 55dBLAeq. 6.7 Additionally, an assessment has been made of the potential ground floor leisure space, and the

implications on the rooms above. This is an indicative calculation only at this stage, but shows that good internal noise levels can be achieved, in principle, with a pub below the bedrooms.

6.8 Based on the above, appropriate conditions can be applied to any planning permission, and as

such, it would appear that noise should not be a determining factor in any application.

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FIGURE 1 –Site Layout Plan Identifying Monitoring Locations

N

B

A

C

D

Tesco delivery yard

Waste ground

Industrial Units

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FIGURE 2 – Proposed Site Layout Plan

N

Mill

Townhouses

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APPENDIX A - Acoustic Terminology in Brief Sound is produced by mechanical vibration of a surface, which sets up rapid pressure fluctuations in the surrounding air. The rate at which the pressure fluctuations occur determines the pitch or frequency of the sound. The frequency is expressed in Hertz (Hz), that is, cycles per second. The human ear is sensitive to sounds from about 20 Hertz to 20,000 Hertz. Although sound can be of one discreet frequency - a ‘pure tone’ - most noise is made up of many different frequencies.

The human ear is more sensitive to some frequencies than others, and modern instruments can measure sound in the same subjective way. This is the basis of the A-weighted sound pressure level dBA, normally used to assess the effect of noise on people. The dBA weighting emphasises or reduces the importance of certain frequencies within the audible range.

Noise Units

In order to assess environmental noise, measurements are carried out by sampling over specific periods of time, such as fifteen minutes or one hour, the statistically determined results being used to quantify various aspects of the noise. The figure below shows an example of sound level varying with time. Because of this time variation the same period of noise can be described by several different levels. The most common of these are described below.

Lmax

Leq

L90

Example of Sound Level Varying With Time

LAeq,T The equivalent continuous (A-weighted) sound level. May be thought of as the “average” sound level over a given time, T. It is used for assessing noise from various sources: industrial and commercial premises, construction sites, railways and other intermittent noises and can be considered as the “ambient” noise level.

LA90 The (A-weighted) sound level exceeded for 90% of a measurement period. It is the value used to describe the “background” noise.

LAmax The maximum (A-weighted) sound level during a measurement period.

Free-field Level This refers to the sound level measured outside, away from reflecting surfaces.

Rw Single number rating used to describe the airborne sound insulation properties of a

material or building element over the frequency range of typically 100-3150Hz.

RTRA Single number rating used to describe the airborne sound insulation properties of a

material or building element over the frequency range of typically 100-3150Hz, using a traffic noise spectrum as the source.

Dn,e,w Weighted element-normalised level difference. Single number rating used to describe the performance of a ventilation unit.

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APPENDIX B – Measurement Procedure Dates & Times of Survey Daytime: Wednesday 10 July 2013, 1030 to 1330h Early morning (“Night-Time”): Friday 19 July 2013, 0530h-0900h Personnel Present Day and Night-Time: Ben Tomlin (AEC) Equipment Used Day and Night-Time: B&K 2260 Real Time Analyser (AEC Kit 2)

Weather Conditions Daytime: 19°C, overcast and calm. Night-Time: 16°C, clear skies and calm. Measurement Procedure Baseline noise levels were measured at 3 locations, identified as A to C

on Figure 1 and described below.

A – On Finsley Gate, opposite the service road leading to the Tesco delivery yard. About 0.5m from the edge of the road.

B – On Finsley Gate, at the other end of the proposed site, about 3m from

the edge of the road. C – On the canal path at the rear of the existing mill. D – On the pavement of the site boundary to the waste ground at the rear

of the site, about 20m from the industrial units. Locations A to C were selected to measure baseline noise levels, which

were measured in terms of LAeq, LA10, L90 and LAmax (fast response) typically over 5 to 15 minute periods.

All the measurements were taken at a height of 1.5m above ground and

all were free field measurements.

The sound level analyser, which conforms to BS EN 61672-12003 ‘Electro acoustics – sound level meters - Part1Specifications’ for Class 1 Type Z meters, was in calibration and check calibrated before and after the measurement periods using a Brüel & Kjær type 4231 (94dB) calibrator. There was no significant drift of calibration.

Measured Data A summary of the results are presented in Tables B1 and B2.

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TABLE B1 –Measured Noise Levels, Daytime

Location Period, h Noise Level, dB

Comments LAeq LA90 LA10 LAmax

A

1027-1032 72.8 59.2 76.8 85.4

Measurements at this location were dominated by noise from traffic on Finslay Gate.

1032-1037 70.6 53.4 74.7 84.2

1037-1042 70.7 52.8 74.9 83.6

1135-1140 70.6 55.7 74.8 83.0

1140-1145 71.6 60.2 75.5 85.0 Delivery observed at Tesco delivery yard, but was inaudible except when no traffic movements.

1145-1150 71.6 55.7 75.8 82.7

Measurements at this location were dominated by noise from traffic on Finslay Gate.

1236-1241 70.9 56.7 75.6 81.4

1241-1246 69.8 54.2 74.1 82.1

1246-1251 70.3 57.9 74.4 82.4

B

1045-1050 65.0 49.5 69.5 75.9

Measurements at this location were dominated by noise from traffic on Finslay Gate.

1050-1055 65.9 50.3 70.1 80.2

1055-1100 65.8 51.4 69.3 78.4

1154-1159 67.4 56.2 70.5 81.6

1159-1204 66.3 54.4 70.3 78.4

1204-1209 66.5 53.4 69.9 77.2

C

1106-1111 48.9 42.0 42.0 66.7

Noise levels at this location were distant traffic, birdsong, and the occasional pedestrian or cyclist.

1111-1116 45.9 43.6 47.9 58.0

1116-1121 46.0 43.5 47.2 69.1

1215-1220 45.8 43.6 47.0 56.3

1225-1230 44.8 43.1 46.0 52.9

1230-1235 45.8 43.7 47.7 56.7

1256-1301 46.0 40.1 46.3 68.9

1301-1306 52.0 42.2 57.2 73.3 Canal boat passed by.

1306-1311 45.9 39.4 46.4 71.1

Noise levels at this location were distant traffic, birdsong, and the occasional pedestrian or cyclist. Max due to demolition activity in the mill.

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TABLE B2 –Measured Noise Levels, Early Morning

Location Period, h Noise Level, dB

Comments LAeq LA90 LA10 LAmax

A

0525-0530 64.1 42.7 66.8 81.5

Deliveries were noted during each of these measurement periods. Otherwise road traffic on Finsley Gate dominated. The loudest maximums were due to HGV pass-bys and/or horns sounding.

0530-0535 65.7 41.7 68.5 82.1

0535-0540 63.9 43.9 65.4 82.0

0540-0545 65.4 46.1 68.3 84.4

0545-0550 64.9 43.1 67.6 81.8

0550-0555 65.7 44.1 66.1 86.7

0556-0601 65.3 44.5 68.6 77.7

0601-0606 66.5 41.0 64.8 80.3

0606-0611 66.3 46.3 69.6 83.9

0611-0616 67.0 47.1 71.1 82.2

0616-0621 63.6 44.5 66.5 80.8

0647-0652 71.5 52.8 75.8 86.3

0652-0657 67.6 47.9 70.9 84.4

0657-0702 67.8 46.6 71.7 84.2

0703-0708 66.0 46.5 69.7 80.6

No deliveries observed. Otherwise road traffic on Finsley Gate dominated.

0708-0713 68.8 49.4 73.4 81.9

0713-0718 67.5 47.8 71.3 85.6

0746-0751 72.5 57.8 77.3 85.8

Deliveries noted. Otherwise road traffic on Finsley Gate dominated. *Due to beeping truck horn next to microphone, not considered a typical event.

0751-0756 72.9 55.6 76.7 91.6

0756-0801 73.8 60.6 76.6 97.8*

0802-0807 72.4 58.9 76.9 83.3

0807-0812 72.9 59.0 77.6 82.9

0812-0817 72.4 61.5 76.5 83.0

B

0820-0825 67.2 58.6 70.5 76.2

Road traffic on Finsley Gate dominated. 0825-0830 67.0 56.9 70.9 76.7

0830-0835 67.7 58.1 71.5 76.5

C

0628-0633 45.4 40.0 48.3 60.4

Noise levels dominated by distant traffic and birdsong.

0633-0638 43.4 38.9 46.0 56.5

0638-0643 43.6 40.7 46.0 56.1

D

0852-0857 60.5 45.9 61.1 80.7

Noise levels dominated by road traffic on Marlborough Street, although a delivery, industrial and vehicle repair activity also contributed.

0857-0902 64.8 48.3 66.6 84.8

Noise levels dominated by road traffic on Marlborough Street, although a delivery, industrial and vehicle repair activity also contributed.

0902-0907 57.2 45.8 55.0 77.9

Noise levels dominated by road traffic on Marlborough Street, although industrial and vehicle repair activity also contributed.