noise impact assessment...bs4142:2014 – methods for rating and assessing industrial and commercial...

Noise Impact Assessment

Version 1.0 (Draft Edition)

Project No: PA143

Report Ref: TH0711164NR1

Issue Date: 16th December 2016

Proposed Wholebake Facility at land adj. B5437,

Corwen

Project Consultant Proofing Consultant

T. Hegan, BSc (Hons) T. Brown, BSc (Hons), MIOA

Acoustic Consultant Acoustic Consultant

[email protected] [email protected]

Peak Acoustics Ltd.

Fernbank House,

Springwood Way,

Macclesfield,

SK10 2XA

Noise Impact Assessment: Proposed Wholebake Facility

T. Hegan T: 01625 667989 Acoustic Consultant E: [email protected] Page 2 of 26

Contents Executive Summary ................................................................................................................................. 4

1. Criteria and Legislation .................................................................................................................... 5

1.1. Guidance Documentation ............................................................................................................. 5

1.2. Target Outcome ........................................................................................................................... 5

2. Noise Sensitive Receptors ............................................................................................................... 6

2.1 Relation of Background Noise Measurements to NSR Locations .................................................. 6

3. Background Noise Measurements .................................................................................................. 7

3.1. Measurement Procedure ............................................................................................................. 7

3.2 Weather Conditions ...................................................................................................................... 7

3.3 Equipment Calibration ................................................................................................................... 7

3.4. Measurement Results................................................................................................................... 7

4. Noise Sources .................................................................................................................................. 8

4.1. Noise Source Map ........................................................................................................................ 8

4.2. Proposed Mitigation Measures .................................................................................................... 9

4.3. Existing Factory Noise Survey ....................................................................................................... 9

5. Specific Sound Level Calculations .................................................................................................... 9

5.1. Delivery and Dispatch Area .......................................................................................................... 9

5.1.1 Lorry Movements ................................................................................................................... 9

5.1.2 Vehicle Loading & Forklift Movements ................................................................................. 10

5.2. Manufacturing Equipment ......................................................................................................... 11

5.3. Plant and Service Equipment ...................................................................................................... 11

5.3.1. Electricity Substation ........................................................................................................... 11

5.3.3 Condenser Units ................................................................................................................... 12

5.3.4 Air Compressor ..................................................................................................................... 12

5.4. Staff Parking Area ....................................................................................................................... 13

5.5. Wellbeing Centre ........................................................................................................................ 14

6. Rating Levels ...................................................................................................................................... 15

7. Rating Level vs Background (BS4142:2014) ....................................................................................... 16

7.1 Rating Level Tables ...................................................................................................................... 16

8. Assessment of Night-time Noise Maxima (WHO Guidelines) ............................................................ 19

9. Assessment Outcomes ...................................................................................................................... 20

9.1. BS4142:2014 Outcomes ............................................................................................................. 20



9.2. Noise Maxima Outcomes ........................................................................................................... 20

10. Conclusion ....................................................................................................................................... 21

Appendix A – Background Noise Level Graphs ..................................................................................... 22

Appendix B – Formulae and Calculations ............................................................................................. 23

Appendix C – Equipment and Calibration Data .................................................................................... 25

Appendix D – Manufacturing Equipment Noise Levels ........................................................................ 26



Executive Summary

A food manufacturing factory is proposed at land adjacent to B5437, Corwen, Denbighshire, LL21 9RR.

The description of the development is as follows:

The proposed erection of a food manufacturing factory with integrated warehousing and office facilities (Class

B2 13,240 sqm), an ancillary employee wellbeing unit (Class D1 600 sqm); with 166 no. vehicle (including mobility

spaces) and 30 no. cycle parking provision, means of vehicular access, servicing, bin storage, plant, electricity

sub-station and associated landscaping provision.

A noise impact assessment has been conducted in order to assess the potential for adverse impact

arising from noise upon nearby Noise Sensitive Receptors (NSRs).

The report considers the full operation of the business throughout both day and night-time hours, and

incorporates sources of noise such as deliveries and dispatches, plant and manufacturing equipment,

electricity substation, staff vehicles and noise arising from an ancillary Wellbeing Centre. Accumulative

noise levels of multiple sources in operation at different times of day have been assessed in order to

determine an impact rating for the development.

Three NSRs have been considered within the assessment, for which two background noise surveys

have been conducted. Levels ranged from 23.8 dB LA90 during the night to 40.2 dB LA90 in the daytime.

A survey of an existing Wholebake facility on Ty'n Llidiart Industrial Estate, Corwen, has also been

conducted in order to obtain an accurate data set for noise levels of manufacturing equipment to be

used within the proposed development.

As well as comparison of continuous noise levels with existing background levels, noise maxima have

also been assessed with a view to ensuring adverse effects are not experienced by local residents due

to impulsive noise from the development.

Under the current scheme, proposed mitigation measures and level of detail available, the

development achieves a rating of ‘low impact’ in line with BS4142:2014. Peak noise levels have been

demonstrated to be adequately attenuated to interior levels below 45 dB LAFmax at NSR locations,

ensuring World Health Organization guidelines for night-time noise maxima are observed.



1. Criteria and Legislation

1.1. Guidance Documentation

Documentation / Standard

BS4142:2014 – Methods for Rating and Assessing Industrial and Commercial Sound

World Health Organization – Guidelines for Community Noise, 1999

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

1.2. Target Outcome

The following criteria have been selected for the assessment based upon the above standards and

guidance documents:

The development will achieve the ‘Low Impact’ criteria of BS4142:2014 by ensuring the

accumulative Rating Level of noise emissions is below the measured background level, as

calculated at each NSR location.

Noise Maxima occurring during night-time hours (23:00-07:00) will not exceed 45 dB LAfmax as

calculated within nearby residential dwellings, in line with World Health Organization and

BS8233:2014 guidelines.



2. Noise Sensitive Receptors

Three Noise Sensitive Receptors (NSRs) have been identified. Site boundary and NSR locations are

shown on the site map below:

NSR 1 – Residential Dwellings on Maesfallen, Approx. 42m from Site Boundary

NSR 2 – Residential Dwellings on Godre’r Gaer, Approx. 275m from Site Boundary

NSR 3 – Residential Dwelling on B5437, Approx. 185m from Site Boundary

- Background Noise Measurement Locations

2.1 Relation of Background Noise Measurements to NSR Locations

Background Noise measurements taken at Position 1 (East) will be used to assess the noise impact

upon NSR 1. Measurements taken at Position 2 (South-West) will be used to assess the noise impact

upon NSRs 2 and 3.

The noise climate at NSR 3 is expected to be most similar to Measurement Position 2, due to their

mutual proximity to adjacent roads. In practice, the background noise level NSR 3 will be slightly higher

due to proximity to existing industrial and commercial properties. Therefore, to assume the

background level is equal to Position 2 is to assume a ‘worst-case’ scenario for the assessment of noise

impact.



3. Background Noise Measurements

3.1. Measurement Procedure

Noise levels were measured by Environoise at two positions during the daytime and night-time

between 14:00 on Friday 14th and 10:25 on Monday 17th October 2016. During attended periods of

the noise survey, notes were taken on the noise climate and weather conditions.

Free field noise levels were measured using Type 1 sound level meters, whose microphones were

mounted at a height of 1.5m. Instrumentation details are given in Appendix C.

3.2 Weather Conditions

All noise level measurements were made over contiguous 15-minute periods. Overall A-Weighted

maximum (LAFmax), ambient (LAeq,15min) and background (LA90,15min) noise levels were measured as well

as associated linear octave band frequencies.

The acoustic consultant was in the vicinity of the site throughout the survey and the reported weather,

deemed acceptable for the noise survey, was:

Start of Noise Surveys: 11 C, 25% cloud cover, dry, wind speeds of 2-6m/s.

End of Noise Surveys: 12 C, 50% cloud cover, dry, wind speeds of 4-8m/s.

3.3 Equipment Calibration

Sound level meters were calibrated at the start and end of the noise surveys. There was no recorded

drift greater than 0.3dB at 1KHz and therefore no corrections to measurements were required. The

calibration chain is traceable to National Standards held at the National Physical Laboratory (NPL).

3.4. Measurement Results

Four key time periods relevant to the assessment are identified below. The reference time interval

under BS4142:2014 is 1-hour for daytime noise (07:00-23:00) and 15-minutes for night-time noise

(23:00-07:00).

Table 1: Measured Background Noise Data

Parameter

Background Noise Level

(dB LA90)

Position 1

Background Noise Level

(dB LA90)

Position 2

Daytime 14:00-15:00 40.2 39.9

Daytime 22:00-23:00 39.9 39.3

Night-time 05:45-06:00 32.3 31.6

Night-time 03:30-03:45 (Lowest Night-

time BG) 23.8 26.8



4. Noise Sources

4.1. Noise Source Map

Shown on the site plan below are the locations of potential noise breakout from the proposed

development.

Figure 1: Noise Source Map

1. Manufacturing Equipment (Food Production Machinery)

2. Plant & Services Machinery (Air Compressor, Refrigeration, Condenser Units)

3. Deliveries and Despatches (Lorry movements, pallet unloading)

4. Forklift Movements (Warehouse area)

5. Staff Parking Noise (Engines, doors)

6. Electricity Substation (Tonal noise)

7. Wellbeing Centre (Music, Fitness Equipment, Air Conditioning Units)



4.2. Proposed Mitigation Measures

A number of mitigation measures against noise have been implemented into the current design or are

proposed to be included. Acoustic fencing such as JAKoustic Highway along the western perimeter

(2.5m height) and along the eastern perimeter (2.0m height) has been specified. These will help to

attenuate noise from the delivery area and staff car park respectively.

Positioning of the deliveries and dispatches area to the west of the site has an acoustical benefit in

that external activities resulting in the highest noise levels are positioned away from the closest NSR

to the site (NSR 1). The manufacturing area is shielded by other areas of the building, which provide a

buffer to noise toward NSR locations.

It is provisionally proposed to enclosure certain internal machines within bespoke enclosures in order

to reduce noise exposure to employees, and this will also result in lower noise levels at NSR locations.

Externally mounted fans are to include silencers to attenuate high noise levels.

4.3. Existing Factory Noise Survey

A site noise survey was conducted on 16th November 2016 at the existing Wholebake facility on Ty'n

Llidiart Industrial Estate, Corwen. Measurements were undertaken using Class 1 Measurement

Equipment which was checked for calibration drift before and after measurements. Equipment was

measured at distances of 1 – 5m from source.

The survey obtained noise levels of a range of equipment currently in use, allowing noise levels at the

proposed factory to be predicted. Noise measurements of a forklift truck unloading pallets was also

taken at a distance of 15m. The results of the measurements are given in more detail in Section 5.2.

5. Specific Sound Level Calculations

5.1. Delivery and Dispatch Area

The primary sources of noise arising from the eastern delivery and despatches area are likely to be the

manoeuvring of lorries, and loading and unloading of pallet-laden goods using forklift trucks. Impulsive

noise emissions such as air-compression brakes are also to be assessed (Section 8.). The facility is not

proposing any deliveries of refrigerated goods and therefore no support power systems (e.g. donkey

engines) are required.

5.1.1 Lorry Movements

In order to assess the noise impact of HGVs using the eastern delivery and dispatches area, noise levels

are derived from data previously obtained by Peak Acoustics at a similar operational factory.

A 40-minute attended measurement was conducted during peak time at the Goods-In area at Aldi

North-West Distribution Centre, Neston. The measurement captured articulated lorries manoeuvring

and accelerating past the measurement position at a distance of 10m.



A correction has been applied to the measured noise level of 61.9 dB LAeq at 10m, to account for the

operational capacity of the proposed Wholebake site, which has provisions for approximately 50% of

the reference site where measurements were taken (six lorries at any one time as opposed to twelve).

A noise level for deliveries at high capacity of 58.9 dB LAeq at 10m is therefore considered. During night-

time hours, a lesser capacity of deliveries and dispatches is likely to occur (a further reduction of 50%)

resulting in a noise level of 55.9 dB LAeq at 10m. (full calculation – Appendix B).

Noise Levels of lorry movements at each NSR for both high and low capacity are summarised in Table

2 below:

Table 2: Lorry Movement Noise Levels

NSR 1 NSR 2 NSR 3

Lorry Movements (High/Low) dB LAeq,T at

10m

(58.9/55.9) (58.9/55.9) (58.9/55.9)

Distance to NSR, m 280.0 285.0 185.0

Distance Attenuation, dB -28.9 -29.0 25.3

Barrier Attenuation -25.2

(Building Shielding) -4.9

(Topography) -7.4

(Acoustic Fencing)

Level at NSR, dB LAs (4.8/1.8) (25.0/22.0) (26.2/23.2)

It is demonstrated that NSRs 2 & 3 will experience noise levels of around 22.0 – 26.2 dB LAeq, whilst

the noise level at NSR1 is negligible.

5.1.2 Vehicle Loading & Forklift Movements

Measurement of a forklift truck unloading pallets from a side-access lorry trailer was undertaken at

the existing Corwen Wholebake facility on 16th November 2016. Measurements were taken at a

distance of 5m to the unloading point of the lorry and were recorded at 62.3 dB LAeq, 2min at 5m. Noise

levels at NSR locations are calculated below:

Table 3: Forklift Movements and Vehicle Loading / Unloading, Noise Levels at NSRs

NSR 1 NSR 2 NSR 3

Forklift Movements, dB LAeq,T at 5m 62.3 62.3 62.3

Distance to NSR, m 280.0 285.0 185.0

Distance Attenuation, dB -34.9 -35.1 -31.4

Barrier Attenuation, dB -25.2

(Building Shielding) -4.9

(Topography) -7.4

(Acoustic Fencing)

Level at NSR, dB LAs 17.2 22.3 23.5



5.2. Manufacturing Equipment

A site noise survey was conducted on 16th November 2016 at the existing Wholebake facility on Ty'n

Llidiart Industrial Estate, Corwen. This allowed likely internal noise levels at the proposed factory to

be predicted based on machinery already in-use.

Measurements of equipment fell in the range of 76 – 85 dB LAeq,T at 1m. A full list of measured noise

levels is shown in Appendix D. To obtain a single, representative level of noise within the factory

manufacturing area, the 12 measurements have been logarithmically averaged to produce a mean

noise level of 80 dB LAeq,T.

A noise breakout calculation has been performed, considering the insulation provided by the building

envelope (estimated to be approx. minimum 2mm single skin steel cladding). The wall has been

acoustically modelled and is estimated to provide a weighted sound reduction induction of 34 dB Rw.

Calculation of noise breakout from manufacturing equipment to NSR locations is shown in Table 4

below:

Table 4: Manufacturing Equipment, Noise Levels at NSRs

NSR 1 NSR 2 NSR 3

Internal Noise Level, dB LAeq 80.0 80.0 80.0

Distance to NSR (Northern Façade to NSR), m 175 400 250

Insulation Rw 34 34 34

Minimum Building Shielding, dB (10dB for full line-of-sight obstruction)

-10.0 -10.0 -10.0

Calculated Breakout to NSR, dB LAs 17.4 10.2 14.3

The design of the building lends itself to prevention of noise breakout to NSR locations. On the east

and western sides, the manufacturing area is shielded by the plant & services area and warehousing

area respectively. On the southern side (facing NSR 2), the manufacturing area is shielded by offices.

The factor of 10dB shielding that has been considered therefore represents the minimum likely to

occur.

5.3. Plant and Service Equipment

5.3.1. Electricity Substation

An external electricity substation with 500kVa transformer is proposed toward the western entrance

to the facility (approx. 200m to nearest NSR). This is to be enclosed within a standard Glass Reinforced

Plastic enclosure approx. 4.5m x 4.5m x 2.0m

Representative manufacturer data for an 800kVa transformer has been utilised, stating a noise level

of 55 dB(A) [1]. The lower-output proposed transformer is likely to be lesser in practice.

The enclosure has been modelled, considering sound leakage through ventilation louvres, in order to predict noise breakout to NSR locations.



Table 5: Transformer Substation, Noise Levels at NSRs

NSR 1 NSR 2 NSR 3

Transformer Noise Level, dB LAeq 55 55 55

Enclosure Insertion Loss, dB -18.6 -18.6 -18.6

Distance to NSR, m 285 294 195

Distance Attenuation to NSR, dB -49.1 -49.3 -45.8

Barrier Attenuation, dB (Acoustic Fencing) -10.4 0.0 -6.4

Level at NSR dB LAs



It is therefore anticipated that the maximum level, after enclosure, will be 80 dB; a level below which

the Lower Exposure Action Value is not exceeded in line with the Control of Noise at Work Regulations

2005.

Table 7: Internal Air Compressor, Noise Levels at NSRs

NSR 1 NSR 2 NSR 3

Air Compressor Noise Level (Before

Enclosure), dB LAeq 95.0 95.0 95.0

Air Compressor Noise Level (After

Enclosure), dB LAeq 80.0 80.0 80.0

Factory, Outer Insulation dB (-)Rw -34.0 -34.0 -34.0

Approx. Noise Level, factory Exterior 46.0 46.0 46.0


Distance Attenuation to NSR -42.3 -52.6 -51.1

Acoustic Fencing Attenuation -8.4

(Acoustic Fencing) -4.9

(Topography) -25.2

(Building Shielding)

Level at NSR dB LAs



Table 8: Staff Vehicle Noise levels

Time Period Total Vehicle Movements dB LAeq,30min (1m)

Morning Change-Over (05:30 – 06:30) 184 (134/46) 64.2

Midday Change-Over (13:30-14:30) 184 (46/134) 64.2

Evening Change-Over (21:30-22:30) 92 (46 / 46) 61.2

Table 9A: Morning Change-Over (05:30-06:30)

NSR 1 NSR 2 NSR 3

Staff Vehicle Parking Noise, dB LAeq (1m) 64.2 64.2 64.2



Barrier Attenuation, dB -9.3 (Acoustic Fencing)

-4.9 (Topography)

-25.2 (Building Shielding)

Level at NSR, dB LAs 16.3 6.4



Table 10: Wellbeing Centre, Condenser Unit Noise Levels

NSR 1 NSR 2 NSR 3

Condenser Units, dB LAeq (1m) 58.0 58.0 58.0



Barrier Attenuation, dB -4.9

(Acoustic Fencing) 0.0

-25.2 (Building Shielding)

Level at NSR, dB LAs 14.6 4.1



7. Rating Level vs Background (BS4142:2014)

In this section, accumulative Rating Levels of equipment are compared with the relevant background

noise level at each NSR for four noise-sensitive scenarios.

7.1 Rating Level Tables Table 12A

Noise Impact Scenario 1: Daytime Noise (14:00-15:00)

Noise Source Rating Level (dB LAr)

NSR 1 NSR 2 NSR 3

Lorry Movements, High Capacity, dB LAr 6.8 27.0 28.2

Vehicle Loading, Forklift Movements, dB LAr 17.2 22.3 23.5

Manufacturing Equipment, dB LAr 17.4 10.2 14.3

Electricity Substation, dB LAr 0.0 0.0 0.0

Refrigeration Condensers, dB LAr 23.1 20.2 12.2

Air Compressor, dB LAr 0.0 0.0 0.0

Staff Parking, Midday Change-Over, dB LAr 19.3 9.4 3.0

Wellbeing Centre, Aircon dB LAr 16.3 5.8 2.0

Combined Rating Level, dB LAr 26.5 28.5 29.7

Background Level, dB LA90 (time) 40.2 39.9 39.9

Difference, dB -13.7 -11.4 -10.2

BS4142 Rating ‘Low Impact’ ‘Low Impact’ ‘Low Impact’



Table 12B

Noise Impact Scenario 2: Evening Noise (22:00-23:00)


NSR 1 NSR 2 NSR 3

Lorry Movements, Low Capacity, dB LAr 3.8 24.0 25.2

Vehicle Loading, Forklift Movements, dB LAr 17.2 22.3 23.5

Manufacturing Equipment, dB LAr 17.4 10.2 14.3


Refrigeration Condensers, dB LAr 23.1 20.2 12.2


Staff Parking, Evening Change-Over, dB LAr 16.3 6.4 3.0



Background Level, dB LA90 (time) 39.9 39.3 39.3

Difference, dB -13.9 -12.7 -11.5


Table 12C

Noise Impact Scenario 3: Early Morning Noise (05:45-06:00)


NSR 1 NSR 2 NSR 3

Lorry Movements, Low Capacity, dB LAr

3.8 24.0 25.2

Vehicle Loading, Forklift Movements, dB LAr

17.2 22.3 23.5

Manufacturing Equipment, dB LAr

17.4 10.2 14.3


Refrigeration Condensers, dB LAr

23.1 20.2 12.2


Staff Parking, Morning Change-Over, dB LAr

16.3 6.4 3.0



Background Level, dB LA90 (time)

32.3 31.6 31.6

Difference, dB -5.8 -5.0 -3.8




Table 12D

Noise Impact Scenario 4: Night-time Noise (03:30-03:45)


NSR 1 NSR 2 NSR 3

Lorry Movements, Low Capacity, dB LAr

3.8 24.0 25.2

Vehicle Loading, Forklift Movements, dB LAr

17.2 22.3 23.5

Manufacturing Equipment, dB LAr

17.4 10.2 14.3


Refrigeration Condensers, dB LAr

23.1 20.2 12.2



Background Level, dB LA90 (time)

23.8 26.8 26.8

Difference, dB +1.7 -0.3 +1.0




8. Assessment of Night-time Noise Maxima (WHO Guidelines)

The method of comparing LAeq and LA90 parameters may not be sufficient on its own to assess the full

scope of noise affecting NSRs.

It is also necessary to consider the possible noise impact of impulsive noise-events (LAFmax)occurring

during night-time hours (23:00-07:00). World Health Organization guidelines state that regularly

occurring night-time noise maxima of over 45 dB LAfmax could cause adverse impact on health.

Potential impulsive noise sources and associated LAFmax noise levels are identified in Table 13 below.

All goods to and from the factory are transported via pallets as opposed to metal roll-cage type

containers.

Table 13: Night-time Noise Maxima, Measurement Details

Noise Source Measurement Details Measured Level, dB

LAFmax dB LAFmax at 1m

Pallet Loading

Peak Acoustics

Measurement at existing

Wholebake facility

74.9 at 5m 88.9

Lorry compression brake

(Typical OEM system)

Jacobs Vehicle Systems [4]

Noise Level Data. 83.0 at 15m 106.5

Car door-close Peak Acoustics

Measurement 84.9 at 1m 84.9

Table 14: Night-time Noise Maxima, Levels at NSRs

Noise Source dB LAFmax at

1m Nearest NSR

Barrier

Attenuation,

dB

Distance

Attenuation

to NSR, dB

Attenuation, partially

open window

(BS8233:2014), dB

Level at

Nearest NSR,

dB LAFmax

Pallet Loading 88.9 NSR 3

(185m) -5.9 -45.3 -15 22.7

Lorry compression

brake (Typical OEM

system)

106.5 NSR 3

(185m) -5.9 -45.3 -15 40.3

Car door-close 84.9 NSR 1

(70m) -6.8 -36.9 -15 26.2

[4] – Jacobs Vehicles Systems – On Engine Brake Noise, December 2000



9. Assessment Outcomes

9.1. BS4142:2014 Outcomes

The total Rating Level (LAr) has been calculated to be below the background noise level (LA90) by 5 – 10

dB at each NSR in 3 out of the 4 representative time periods that were selected for the assessment.

Based upon the current information, this indicates a very low likelihood of adverse impact arising from

noise.

In one time period (03:30-03:45), representing background levels at their lowest, the total Rating Level

was found to be 1.0-1.7 dB above the background noise level. At NSR 1 this was caused predominantly

by the condenser units, the noise level of which has been estimated, as a final specification has not

yet been determined. At NSR 3, the excess was caused predominantly by lorry movements in the

western delivery area.

In assessing the level of adverse impact, it is necessary to consider absolute noise levels, as supported

by BS4142:2014 guidance:

‘For a given difference between the rating level and the background sound level, the

magnitude of the overall impact might be greater for an acoustic environment where the

residual sound level is high than for an acoustic environment where the residual sound level is

low’

The background noise levels of 23.8 – 26.8 dB LA90 recorded during the time period in question are

very low due to the absence of existing noise sources in the locality.

Taking context into consideration, it is therefore determined that the noise impact of the development

is rated as ‘low impact’ in line with BS4142:2014.

9.2. Noise Maxima Outcomes

Maximum noise levels have been assessed to demonstrate that impulsive noise events will not cause

adverse effects such as sleep disturbance at NSR locations (Section 8).

Commonly occurring LAFmax noise levels have been shown to be adequately attenuated to levels below

45 dB within bedrooms of nearby dwellings, taking into account open windows. This attenuation is

provided primarily by the propagation of sound over distance as well as effective mitigation in the

form of acoustic fencing.

The development is therefore deemed to comply with WHO Guidelines for noise maxima during night-

time hours.



10. Conclusion

The Noise Impact Assessment has identified that, whilst high noise levels are likely to be generated by

internal machinery, the insulation of the building is adequate in attenuating internal noise sources to

desirable levels at NSR locations.

External noise sources, namely activities occurring in the western delivery and dispatches bay and

plant such as condenser units located on the eastern side of the structure, are therefore deemed to

be the causes of the highest noise levels.

Mitigation measures implemented into the designs, as well as natural attenuation of sound over

distance have been shown to reduce noise to levels which are classed as ‘low impact’ under the

assessment to BS4142:2014.

It has also been demonstrated that maximum individual noise events likely to occur will be adequately

attenuated, ensuring World Health Organization and BS8233:2014 guidelines for night-time noise

maxima are adhered to.

The conclusions of this draft report are based on the current proposal and level of detail currently

ascertained. The final Noise Impact Assessment to be submitted with the application will take into

account more precise details, locations and noise levels of equipment as they become available.



Appendix A Background Noise Level Graphs

Background Noise Levels, 14th – 17th October 2016, Position 1

Background Noise Levels, 14th – 17th October 2016, Position 2

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Appendix B Formulae and Calculations

I. Distance Correction Formula:

Sources are considered to exhibit point-source distance attenuation as follows:

(Where L2 is the distance corrected level, L1 is the level at source, r1 is the distance at which the source was

measured and r2 is the distance to be corrected to)

II. Calculation of LAeq Noise Levels from Parking Vehicles

Levels of sound from parking vehicles is calculated as follows (representative example – Midday

Change-over):

LAeq, 1hr = LAE + 10log(n) – 10log(t)

LAeq, 1hr = 77.4dB +10log(184 events) – 10log(60sec x 60min)

LAeq, 1hr = 64.2 dB

III. Correction for Capacity of Lorry Deliveries

To obtain 50% of the measured noise level:



IV. Example Barrier Calculation

Barrier calculations are made on the principal of path difference using the Maekawa formula and

take into account topography of the land, source height and receiver height:

Example: Staff Car Park to NSR 1

Barrier Calculation Staff Car Park to NSR1

D Bar-to-Source, (m) 10

(D) Source Height from Ground 4

D Bar-to-NSR, (m) 75

(F) NSR Height from Ground 1.5

(E) BarrierTop Height from G0 5

(C) Direct Path 85.0

(A) Source-to BarrierTop, m 10.05

(B) NSR-to-BarrierTop, m 75.08

Path Diff., m 0.09

Nominal Frequency (Hz) 500

Velocity (m/s) 343

Wavelength 0.686

Fresnel Number (N) 0.28

Barrier Attenuation A, (dB) 9.3



Appendix C Equipment and Calibration Data

Equipment and calibration Data, On-site Measurements 16th November 2016

Equipment

Kit Equipment Make Model Class Serial Number

A1 Sound Meter Svantek 958 1 34525

A1 Pre-Amp Svantek SV12L 1 41651

A1/A3 Calibrator Svantek SV31 1 32507

Calibration

Measurement Calibrator Ref Level

(dB)

Level Before

(dB)

Deviation Before

(dB)

Level After

(dB)

Deviation After

(dB)

M1 114.0 114.20 -0.20 114.50 -0.50



Appendix D Manufacturing Equipment Noise Levels

Machine Measured

Level Line / Point

R1 Level at 1m

Craft Bakery Oven 80.6 20 1 80.6

Sewtec Automation Machine 79 20 2 85.0

Craft Bakery Mixer 78.9 20 1 78.9

2nd Fruit Bar Line, Far End (Boxing) 78.5 10 1 78.5

2nd Fruit Bar Line, Mid Point 77.9 10 1 77.9

2nd Fruit Bar Line, Loading End 76.1 10 2 79.1

Fruit Bar Line O/H Extractor 74.1 20 1.5 77.6

Fruit Bar Line Load-In 76.3 10 1 76.3

Fruit Bar Line Mixer Unit 78.5 10 1 78.5

Fruit Bar Line Central 76.4 10 1.5 78.2

Fruit Bar Line End Packing 75.9 10 3 80.7

noise impact assessment...bs4142:2014 – methods for rating and assessing industrial and commercial...

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