noise modelling report · 2020. 4. 25. · dk/19/11051nr01 awn consulting limited _ _ page...

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Technical Report Prepared For

Intel Ireland Leixlip Campus

R148 Easton

Co. Kildare

_____________________________________ Technical Report Prepared By

Damian Kelly BSc (Hons) MSc MIOA

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Our Reference

DK/19/11051NR01

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Date of Issue

22 November 2019

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NOISE MODELLING REPORT

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DK/19/11051NR01 AWN Consulting Limited _____________________________________________________________________________________________________

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Document History

Document Reference Original Issue Date

DK/19/11051NR01 22 November 2019

Revision Level Revision Date Description Sections Affected

Record of Approval

Details Written by Approved by

Signature

Name Damian Kelly Stephen Smyth

Title Director (Acoustics) Associate (Acoustics)

Date 22 November 2019 22 November 2019

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EXECUTIVE SUMMARY Intel Ireland are currently progressing detailed design of a proposed extension (i.e. The Revised Extended Manufacturing Facility (REMF)) at their existing facility at Leixlip, Co. Kildare including the removal of the North Mound and noise emissions associated with Site Support Services. As part of the Licence application to the EPA (required to operate the development) a detailed noise impact assessment must be undertaken and details in relation to noise emissions associate with the operation of the site submitted. This technical report has been prepared to provide full details in relation to the noise impact assessment for the licence application. The assessment is based on the most up-to-date design details available for development and has been prepared with due consideration of the guidance contained within the Environmental Protection Agency (EPA) document Guidance Note for Noise: Licence Applications, Surveys and Assessments in Relation to Scheduled Activities (NG4) 2016. Section 6 of the EPA’s NG4 Guidance outlines the following assessment stages for the noise impact assessment for licence applications.

• Stage 1 – Baseline Noise Survey / Monitoring Locations;

• Stage 2 – Derivation of Noise Criteria;

• Stage 3 – Assessment of Noise Impact; and,

• Stage 4 – Reporting / Licence Application Form. This report has been prepared with consideration of the four assessment stages outlined above. An environmental noise survey was conducted to quantify the existing noise environment in the vicinity of nearest Noise Sensitive Receivers (NSL’s) to the site. The survey was conducted in accordance with the EPA’s NG4 Guidance. Appropriate operational noise criteria have been derived for the site following review of noise survey data and receiving environment, in accordance with the relevant NG4 Guidance and existing licence noise conditions. The applicable noise criteria identified are in line with the typical limit values for noise from licensed sites. To assess the impact of noise from new mechanical plant at nearby NSL’s, a detailed computer-based noise model has been prepared using proprietary noise modelling software package, Brüel & Kjær Predictor. Noise prediction calculations have carried out in accordance with ISO 9613-2:1996 Acoustics – Attenuation of sound during propagation outdoors – Part 2: General method of calculation. The predicted noise levels at all NSL’s for new mechanical plant and the levels of existing plant noise from the facility are within the day, evening and night-time noise criteria for site operations. It should be noted that noise impact assessment has been completed using information obtained from the design team for significant items of plant which are currently being procured from vendors. It is anticipated that where there is any substantial variation in the noise emission level of plant when installed on site (i.e. that has not been accounted for in the data used for this assessment), additional noise control measures such as, acoustic barriers or attenuator systems will be employed where necessary, to ensure that the operation of the facility will comply with the required noise criteria set out in this report or defined in the Licence issued to the operator.

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CONTENTS Page

Executive Summary 3

1.0 Introduction 5

2.0 Fundamentals of Acoustics 6

3.0 Receiving Environment 7

3.1 Choice of Measurement Locations 7

3.2 Survey Periods 9

3.3 Instrumentation 9

3.4 Procedure 10

3.5 Measurement Parameters 10

3.6 Survey Results 11

4.0 Review of Relevant Guidance & Existing Licence 16

4.1 Existing Licence 16

4.2 Quiet Area Screening 17

4.3 Low Background Noise Area Screening 17

4.4 Determining Appropriate Noise Criteria 18

4.5 Compliance Noise Monitoring 19

5.0 Assessment 20

5.1 Noise Sensitive Locations 20

5.1 Noise Source Data 21

5.2 Calculation Methodology 21

5.3 Predicted Noise Levels 22

6.0 Conclusion 26

Figure 1 – Site Location & Context 5

Figure 2 – Level of Typical Sounds on dB(A) Scale 6

Figure 3 – Noise Monitoring Locations 8

Figure 4 – Noise Prediction Locations 24

Figure 4 – Operational Noise Prediction Contours 24

Appendix A – Glossary of Acoustic Terminology 27

Appendix B – Noise Model and Impact Assessment Details 30

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1.0 INTRODUCTION Intel Ireland are currently progressing detailed design of a proposed extension (i.e. Project REMF) to their existing facility at Leixlip, Co. Kildare. AWN Consulting has been commissioned to prepare a noise impact assessment for the operation of the facility to be compiled and submitted as part of the Industrial Emissions (IE) licence application process. This preliminary assessment is based on the existing noise emissions from the facility and the most up-to-date design details available for the development and has been prepared with due consideration to the guidance contained within the Environmental Protection Agency (EPA) document Guidance Note for Noise: Licence Applications, Surveys and Assessments in Relation to Scheduled Activities (NG4) 2016. This report has been prepared in accordance with the four noise impact assessment stages outlined in Section 6 of NG4, which are as follows:

• Stage 1 – Baseline Noise Survey / Monitoring Locations;

• Stage 2 – Derivation of Noise Criteria;

• Stage 3 – Assessment of Noise Impact; and,

• Stage 4 – Reporting / Licence Application Form.

Figure 1 illustrates the proposed site location in the context of the surrounding environment

Figure 1 Site Location & Context

Intel’s lands at Collinstown Industrial Park are situated directly to the west of the town of Leixlip in Co. Kildare. The Intel campus is situated on a site of ca. 160 hectares, west of Leixlip at the Collinstown Industrial Park. The campus is bounded by the Sligo to Dublin Railway Line and the Royal Canal to the east, by Kellystown Lane to the west and by the River Rye to the north. The site of the proposed development is mainly to the west of the Intel campus – west of the office building known as IR5. Appendix A presents a glossary of the acoustic terminology referred to in this document.

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2.0 FUNDAMENTALS OF ACOUSTICS

In order to provide a broader understanding of some of the technical discussion in this report, this section provides a brief overview of the fundamentals of acoustics and the basis for the preparation of this noise assessment. A sound wave travelling through the air is a regular disturbance of the atmospheric pressure. These pressure fluctuations are detected by the human ear, producing the sensation of hearing. In order to take account of the vast range of pressure levels that can be detected by the ear, it is convenient to measure sound in terms of a logarithmic ratio of sound pressures. These values are expressed as Sound Pressure Levels (SPL) in decibels (dB). The audible range of sounds expressed in terms of Sound Pressure Levels is 0dB (for the threshold of hearing) to 120dB (for the threshold of pain). In general, a subjective impression of doubling of loudness corresponds to a tenfold increase in sound energy which conveniently equates to a 10dB increase in SPL. It should be noted that a doubling in sound energy (such as may be caused by a doubling of traffic flows) increases the SPL by 3dB. The frequency of sound is the rate at which a sound wave oscillates and is expressed in Hertz (Hz). The sensitivity of the human ear to different frequencies in the audible range is not uniform. For example, hearing sensitivity decreases markedly as frequency falls below 250Hz. In order to rank the SPL of various noise sources, the measured level has to be adjusted to give comparatively more weight to the frequencies that are readily detected by the human ear. Several weighting mechanisms have been proposed but the ‘A-weighting’ system has been found to provide one of the best correlations with perceived loudness. SPL’s measured using ‘A-weighting’ are expressed in terms of dB(A). An indication of the level of some common sounds on the dB(A) scale is presented in Figure 2. The established prediction and measurement techniques for the dB(A) parameter are well developed and widely applied. For a more detailed introduction to the basic principles of acoustics, reference should be made to an appropriate standard text1.

Figure 2 Level of Typical Sounds on the dB(A) Scale – (TII – Good Practice Guidance for the Treatment of Noise during the Planning of National Road Schemes March 2014 , National Roads Authority.)

1 For example, Woods Practical Guide to Noise Control by Ian Sharland.

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3.0 RECEIVING ENVIRONMENT This section deals with ‘Stage 1’ of the noise impact assessment as outlined in the EPA’s NG4 Guidance. An environmental noise survey was conducted by AWN in support the planning application for the proposed extension in 2018 and also to comply with existing IE licence reporting requirements. One of the purposes of the survey was to quantify the existing noise environment at nearby noise sensitive locations in light of existing site noise emissions. The surveys were conducted in accordance with guidance contained in the EPA NG4 publication and ISO 1996: 2007: Acoustics – Description, measurement and assessment of environmental noise. Details of this survey are presented in the following sections. It should be noted that the existing noise surveys take account of noise from the existing facility.

3.1 Choice of Measurement Locations

Noise measurements were conducted at eight positions on the site boundary and at noise-sensitive locations. Eight of these positions are the monitoring locations as conducted for the annual IE License noise survey for the site, as outlined below.

Location Description Coordinates

Notes E N

NM-1 Along Kellystown lane near the ‘Middle Gate’ on the western boundary of the site.

297,934 237,503

Boundary Location – approx. 70m additional distance from monitoring location to nearest NSL.

NM-2

Along the Dunboyne Road to the north of the site, at the entrance to the Intel soccer grounds.

298,236 237,946 Boundary Location. No residential housing in close proximity to this measurement position.

NM-3 At Riverview House to the north of the site.

298,686 237,708 The noise monitor was positioned adjacent to the Riverview property

NM-4 Along the Dunboyne Road at Confey to the north of the site.

299,316 237,826 The noise monitor was positioned at the entrance to a field adjacent to nearby residential properties

NM-5

At the north-eastern Intel site boundary. The noise monitor was positioned in the corner of the car-park to the east of Fab24

299,331 236,701

Boundary Location - approx. 220m additional distance from monitoring location to nearest NSL beyond railway line.

NM-6

At the south-eastern Intel site boundary. The noise monitor was positioned in the corner of the car-park to the east of Fab24

299,311 236,593

Boundary Location - approx. 180m additional distance from monitoring location to nearest NSL beyond railway line

NM-7 At noise-sensitive locations beyond the southern boundary of the Intel site.

298,708 236,480

The monitoring position is to the rear of properties within Glen Easton Woods Estate at the boundary with the railway line

NM-8 At a noise-sensitive location north-east of the site along Dunboyne Road at Confey.

299,658 237,691 The monitoring position is in the rear garden of the dwelling.

Table 1 Measurement Locations & Descriptions

These locations are shown on Figure 3.

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DK/19/11051NR01 AWN Consulting Limited ____________________________________________________________________________________________________________________________________________________________

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Figure 3 Noise Monitoring Locations

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3.2 Survey Periods Measurements were conducted over the course of the following survey periods:

Survey

Reference Period Location Date and Time Survey Personnel

Normal Site Operation

Daytime

NM01, NM02 15:43hrs to 19:21hrs on 31

May 2018

Donogh Casey (AWN)

NM03, NM04, NM08

10:16hrs to 15:40hrs on 8 June 2018

NM05, NM06, NM07

11:30hrs to 17:56hrs on 15 June 2018

NM07

17:15hrs to 17:45hrs on 29 August 2018

12:11hrs to 12:41hrs on 22 October 2018

James Mangan (AWN)

Evening

NM01, NM02, NM03, NM04

19:02hrs to 21:26hrs on 29 August 2018 Donogh Casey

(AWN) NM05, NM06, NM07, NM08

19:49hrs to 22:50hrs on 3 October 2018

Night-time

NM01, NM04 23:25hrs to 01:02hrs on

29/30 August 2018 Donogh Casey

(AWN) NM02, NM03, NM05, NM06, NM07, NM08

23:00hrs to 03:21hrs on 3/4 October 2018

Table 2 Summary of Noise Survey Periods

The weather conditions over the course of various survey periods are summarised below.

Date Period Wind Speed

(m/s) Wind

Direction Precipitation

Temperature (oC)

31 May 2018 Day <2 N/NE/E 0 22

8 June 2018 Day <3 N/NE 0 21

15 June 2018 Day <1 N/NW/W/SW 0 14

29 August 2018 Day/Eve <1 NW/W/SW 0 12

30 August 2018 Night <1 NW/S 0 9

3 October 2018 Eve/Night <3 SW/W 0 15

4 October 2018 Night <2 SW/W 0 12

22 October 2018 Day <4 W 0 12

Table 3 Summary of Weather Conditions

3.3 Instrumentation

The measurements at locations NM01 to NM08 were performed using the following equipment:

Manufacturer Equipment Model Serial Number Microphone Calibration date

Brüel and Kjaer Type 2250 2818080 2804243 22/08/2017

Table 4 Instrumentation (NM01 – NM08)

The microphone was protected using a proprietary Brüel and Kjær windshield. Before and after the survey the measurement apparatus was check calibrated using Brüel & Kjær Type 4231 Sound Level Calibrators. Field Calibration: Using the Type 4231 Sound Level Calibrator that produces a sound level of 93.8dB re. 2x10-5 Pa, at a frequency of 1k Hz. The instrumentation used was calibrated before and after use to an accuracy of ± 0.1dB.

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3.4 Procedure

During each of the survey periods, measurements were conducted on a cyclical basis. Sample periods for attended measurements were 30 minutes during day and evening periods and 15-minuted during night-time periods. The results were saved to the instrument memory for later analysis where appropriate. Survey personnel noted all primary noise sources contributing to noise build-up.

3.5 Measurement Parameters

The survey results are presented in terms of the following parameters: LAeq is the equivalent continuous sound level. It is a type of average and is used

to describe a fluctuating noise in terms of a single noise level over the sample period.

LAFmax is the instantaneous maximum sound level measured during the sample

period. LAFmin is the instantaneous minimum sound level measured during the sample

period. LA10 is the sound level that is exceeded for 10% of the sample period. It is

typically used as a descriptor for traffic noise. LA90 is the sound level that is exceeded for 90% of the sample period. It is

typically used as a descriptor for background noise. The “A” suffix denotes the fact that the sound levels have been “A-weighted” in order to account for the non-linear nature of human hearing. All sound levels in this report are expressed in terms of decibels (dB) relative to 2x10-5 Pa. Another parameter that will be commented upon in this report is the LArT. LAr T The LAeq during a specified time interval, plus specified adjustments for

tonal character and impulsiveness of the sound. It should be noted for this assessment it has been assumed that detailed design will be carried out in order that there will be not tonal or impulsive noise emissions for the development. Therefore, in this instance LAeq is equal to LAr T.

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3.6 Survey Results

3.6.1 Location NM01

Period/Time Measured Noise Levels, dB re 2x10-5 Pa

LAeq LAFmax LAmin LA10 LA90

Daytime

15:43-16:13 51 68 35 54 41

16:59-17:29 52 63 36 55 43

18:15-18:45 51 65 39 54 44

Evening 20:56-21:26 48 67 31 51 35

Night-time 00:00-00:15 37 59 31 38 33

00:23-00:38 41 63 31 39 32

Table 5 Noise Monitoring Results – Location NM01

During the daytime survey periods, road traffic movements on the R148 and Kellystown Lane were noted as the primary contributors to the noise environment. Birdsong and aircraft flyover were also noted. Plant noise from the Intel site was just audible at this location during the daytime monitoring period. Local vehicles were the dominant source of noise in relation to the LAeq and LAmax noise parameters. The ambient noise level was in the range of 51 to 52dB LAeq,30min. Background noise levels were in the range 41 to 44dB LA90,30min. During the evening survey period, the dominant noise sources were traffic on the Kellystown Lane and distant traffic on the R148 further in the distance. Intel plant noise was noted as being just audible. The ambient noise level was 48dB LAeq,30min. The background noise level was 35dB LA90,30min. During the night-time survey period, contributing sources were noted to be occasional traffic on Kellystown Lane and the Intel plant noise was noted as dominant. Ambient noise levels were in the range 37 to 41dB LAeq,15min. Background noise levels were in the range 32 to 33dB LA90,15min.

3.6.2 Location NM02



Daytime

16:21-16:51 48 75 33 50 38

17:37-18:07 47 62 32 51 37

18:51-19:21 46 60 34 50 38

Evening 20:15-20:45 47 63 33 49 37

Night-time 23:46-00:01 42 56 37 43 39

00:33-00:48 40 58 34 39 35


During the daytime survey audible noise sources included dominant road traffic noise, intermittent aircraft flyover and birdsong. Steady plant noise was just audible in the distance at this location and during lulls in local traffic. The third daytime measurement was delayed due to local activity in the area and as a result the measurement period extended into the evening period by 21 minutes. There was no noted difference between the noise sources just before/after 19:00. Ambient noise levels were in the range 46 to 48dB LAeq,30min. The background noise levels were in the range 37 to 38dB LA90,30min.

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During the evening survey period, contributing noise levels included distant traffic noise and birdsong. Steady plant noise was discernible. The ambient noise level was 47dB LAeq,30min. The background noise level was 37dB LA90,30min. During the night-time survey periods, the noise environment was comprised of distant road traffic and low level plant noise was the dominant noise source. Ambient noise levels were in the range 40 to 42dB LAeq,15min. Background noise levels were in the range 35 to 39dB LA90,15min.

3.6.3 Location NM03



Daytime

10:16-10:46 46 75 30 44 33

12:13-12:43 41 67 31 43 34

14:00-14:30 42 61 32 43 36

Evening 19:38-20:08 48 63 33 51 36

Night-time 23:22-23:37 41 65 38 42 40

00:10-00:25 40 62 36 41 38


During the daytime survey steady plant noise, mobile plant, intermittent distant road traffic and aircraft flyover contributed to measured noise levels. The ambient noise levels were in the range 41 to 46dB LAeq,30min. Background noise levels were in the range 33 to 36dB LA90,30min. During the evening survey period, steady plant and intermittent mobile plant noise was noted. Other noise sources included distant traffic and birdsong. The ambient noise level was 48dB LAeq,30min. The background noise level was 36dB LA90,30min. During the night-time survey periods, the noise environment comprised of steady plant noise from the Intel site and distant traffic noise. Ambient noise levels were in the range 40 to 41dB LAeq,15min. Background noise levels were in the range 38 to 40dB LA90,15min.

3.6.4 Location NM04



Daytime

10:58-11:28 54 73 26 58 32

12:49-13:19 54 72 27 58 33

14:36-15:06 57 75 30 61 36

Evening 19:02-19:32 61 81 34 63 39

Night-time 23:25-23:40 36 68 27 32 29

00:47-01:02 50 76 26 37 27


During the daytime survey periods, sources contributing to measured noise levels included distant traffic, birdsong, livestock, aircraft flyover and intermittent dog barking. Plant noise was not noticeable during the three monitoring periods. Ambient noise levels were in the range 54 to 57dB LAeq,30min. Background noise levels were in the range 32 to 36dB LA90,30min. During the evening survey period, the noise environment comprised distant traffic noise, intermittent aircraft flyover and farm animal noises. Agricultural machinery

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was observed operating in a nearby field and was contributing to the measured noise levels. The ambient noise level was 61dB LAeq,30min. The background noise level was 39dB LA90,30min. During night-time periods, the noise environment comprised distant plant, distant traffic and intermittent aircraft flyover. During the second night-time period the measurement was influenced by activity from the nearby residential property. Ambient noise levels were in the range 36 to 50dB LAeq,15min. Background noise levels were in the range 27 to 29dB LA90,15min.

3.6.5 Location NM05



Daytime

11:30-12:00 50 67 45 52 47

14:17-14:47 50 65 44 51 47

16:53-17:23 50 69 43 51 46

Evening 19:49-20:19 51 71 46 53 48

Night-time 01:46-02:01 41 58 37 42 39

02:25-02:40 40 56 36 42 38


During the daytime survey, steady plant noise and intermittent mobile plant noise was dominant at this location. Other noise sources included local road traffic, intermittent aircraft flyover, infrequent railway noise and foliage noise. Ambient noise levels were 50dB LAeq,30min. Background noise levels were in the range 46 to 47dB LA90,30min. During the evening survey period, distant road traffic on the R148 and M4, intermittent aircraft flyover, cheering from spectators at local football pitch and foliage noise were noted to influence the measured values. Plant noise was audible and steady. The ambient noise level was 51dB LAeq,30min. The background noise level was 48dB LA90,30min. During the night-time survey periods, the plant noise was dominant with distant road traffic on the R148 and M4 noted to influence the measured values. Ambient noise levels were in the range 40 to 41dB LAeq,15min. Background noise levels were in the range 38 to 39dB LA90,15min.

3.6.6 Location NM06



Daytime

12:06-12:36 53 73 47 54 49

14:51-15:21 55 77 48 57 51

17:26-17:56 53 73 46 54 49

Evening 20:22-20:52 52 73 47 54 49

Night-time 02:04-02:19 39 56 32 40 35

02:43-02:58 41 58 34 44 36


During the daytime survey periods, traffic noise on the adjacent road dominated the measured levels, with plant noise audible during lulls. Occasional activity in the car park, intermittent aircraft flyover and railway noise were observed. Ambient noise

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levels were in the range 53 to 55dB LAeq,30min. Background noise levels were in the range 49 to 51dB LA90,30min. During the evening survey period, distant road traffic on the R148 and M4 was the dominant noise source. Other noise sources included intermittent aircraft flyover and railway noise, along with spectators shouting at local football grounds. Plant noise was barely audible. The ambient noise level was 52dB LAeq,30min. The background noise level was 49dB LA90,30min. During the night-time survey periods, steady plant noise was dominant. Other noise sources included distant and local road traffic noise. Ambient noise levels were in the range 39 to 41dB LAeq,15min. Background noise levels were in the range 35 to 36dB LA90,15min.

3.6.7 Location NM07



Daytime

12:48-13:18 55 66 47 58 51

17:15-17:45 54 69 44 56 49

12:11-12:41 51 65 43 53 47

Evening 21:01-21:31 52 69 44 53 46

Night-time 01:23-01:38 40 52 33 42 35

03:06-03:21 41 60 31 44 36


During the daytime survey noise levels were dominated by traffic noise, in particular on the R449. Plant noise was not discernible during measurements. Other noise sources included noise from elsewhere in the estate, birdsong and aircraft flyover. The ambient noise level was 51 to 55dB LAeq,30min. Background noise levels were in the range 47 to 51dB LA90,30min. During the evening survey period, the noise environment was dominated by distant traffic on the R449, railway noise and activity from the sports ground to the north of the location. Plant noise from the Intel site was not audible during the evening measurement period. The ambient noise level was 52dB LAeq,30min and the background noise level was 46dB LA90,30min. During the night-time period, distant and local traffic movements were noted to be the dominant noise source. Steady plant noise from the Intel site was audible during the night-time measurement periods. Ambient noise levels were in the range 40 to 41dB LAeq,15min. Background noise levels were in the range 35 to 36dB LA90,15min.

3.6.8 Location NM08



Daytime

11:37-12:07 39 63 29 42 33

13:24-13:54 40 64 29 43 32

15:10-15:40 45 67 30 44 33

Evening 22:20-22:50 47 70 38 43 40

Night-time 23:00-23:15 40 57 37 41 39

00:56-01:11 38 54 34 39 36


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During the daytime survey faint plant noise was just difficult to distinguish over the background noise. Other sources included traffic on the nearby road, birdsong, occasional aircraft flyover and resident activity at nearby property. Ambient noise levels were in the range 39 to 45dB LAeq,30min. Background noise levels were in the range 32 to 33dB LA90,30min. During the evening survey period, the noise environment comprises steady plant noise from the Intel site and distant traffic noise. Other noise sources included distant road traffic noise and intermittent aircraft flyover and dogs barking. The ambient noise level was 47dB LAeq,30min and the background noise level was 40dB LA90,30min. During the night time survey period steady plant noise was dominant with intermittent distant traffic noise also audible. The ambient noise levels were in the range 38 to 40dB LAeq,15min and the background noise levels were in the range 36 to 39dB LA90,15min.

3.6.9 Discussion of Current Site Noise Emissions

The LAeq values are a type of average of the noise level during the measurement period. As it is a logarithmic average, it is especially sensitive to relatively loud noises of short duration. For example, a single passage of a vehicle can govern the LAeq value of a measurement over a period much longer than the time for which the vehicle was audible. Thus, where the noise emissions are steady, as plant items are in continuous operation, the LA90 value better reflects the magnitude of these emissions. The EPA NG4 document acknowledges this and comments that ‘it may be appropriate to use the LAF90,T indicator to give a good indication of the actual noise output from the site, provided noise emissions from the site are steady’. Ambient noise levels (i.e. LAeq,T) at the locations discussed here are typically dictated by road traffic and other anthropogenic sources. Background noise levels are influenced by distant traffic noise, other anthropogenic sources, weather conditions and at certain locations Intel operations to varying degrees. In addition, review of one-third octave band data confirms that there is no audible tonal component to Intel noise emissions at any NSL’s. The conclusions of the survey is that the noise emissions specifically from the Intel Ireland site are currently within the daytime, evening and night-time limit values laid out in the IE licence.

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4.0 REVIEW OF RELEVANT GUIDANCE & EXISTING LICENCE

This section deals with ‘Stage 2’ of the noise impact assessment as outlined in the EPA’s NG4 Guidance. The discussion of appropriate IE Licence noise emission criteria for the overall facility will be conducted in accordance with the NG4 document with due consideration of the existing noise limits that the site operates under. This approach is summarised below in accordance with guidance detailed in Section 4 of the NG4 document.

4.1 Existing Licence It is a requirement of the Integrated Industrial Emissions Control (IEL) Licence, issued by the Environmental Protection Agency (EPA) and held by Intel Ireland that environmental noise levels in the vicinity of the site are monitored on an annual basis and do not exceed prescribed levels. Condition 4.5 of the IEL (Register No. P0207-04) states the following: 4.5 Noise

Noise from the installation shall not give rise to sound pressure levels (LAeq,T) measured at NSLs which exceed the limit value(s).

Section 6.22 goes on to state the following:

6.22.1 Noise

The licensee shall carry out a noise survey of the site operations annually. The survey programme shall be undertaken in accordance with the methodology specified in the ‘Guidance Note for Noise: Licence Applications, Surveys and Assessment in Relation to Scheduled Activities (NG4)’ as published by the Agency.

Schedule B.4 pertains to noise and specifies the following limits:

B.4. Noise Emissions

Daytime dB LAr,T

(30 minutes) Evening time dB LAr,T

(30 minutes) Night-time dB(A) LAeq,T

(15 minutes)

55 50 45 Note 1 Note 1: There shall be no clearly audible tonal or impulsive component in the noise emission from the

site at any noise sensitive location.

Schedule C.5 states the following in relation to ‘noise monitoring’: C.5 Noise Monitoring No additional noise monitoring is required in this schedule. Daytime is taken as 07:00 to 19:00hrs, evening 19:00 to 23:00hrs and night-time 23:00 to 07:00hrs as outlined in the NG42 document. The term NSL referenced above relates to Noise Sensitive Location.

2 Environmental Protection Agency (EPA), Office of Environmental Enforcement (OEE), Guidance Note

for Noise: Licence Applications, Surveys and Assessments in Relation to Scheduled Activities (NG4) (2016)

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4.2 Quiet Area Screening The proposed development is not considered a quiet area in this instance as it fails to meet all the criteria outlined in EPA’s Guidance. The most stringent of these criteria are noted in bullet point and commented on below.

• At least 3km from urban area with a population >1,000 people; The town of Leixlip is located less than 3km from the site and has a population of greater significantly greater than 1000.

• At least 3km away from any local industry;

The current facility is operational, in addition to this there are numerous facilities with 3km of the site.

• At least 5km away from any National Primary Route; The site is located approximately 1.5km from the M4 national road.

4.3 Low Background Noise Area Screening In order to establish whether the noise sensitive locations in the vicinity of the site would be considered ‘low background noise’ areas, the noise levels measured during the environmental noise survey need to satisfy all three of the following criteria:

• Arithmetic Average of LA90 During Daytime Period ≤40dB LA90, and;

• Arithmetic Average of LA90 During Evening Period ≤35dB LA90, and;

• Arithmetic Average of LA90 During Night-time Period ≤30dB LA90. The arithmetic average LA90 results at each location are compared against the criteria in Table 14.

Location Period Average LA90,15iin

(dB) NG4 Screening (dB LA90,15min)

Satisfies All Criteria for Low Background

Noise Area?

NM01

Daytime 43 ≤40

No Evening 35 ≤35

Night-time 33 ≤30

NM02

Daytime 38 ≤40

No Evening 37 ≤35

Night-time 38 ≤30

NM03

Daytime 34 ≤40

No Evening 36 ≤35

Night-time 39 ≤30

NM04

Daytime 34 ≤40

No Evening 39 ≤35

Night-time 28 ≤30

NM05

Daytime 47 ≤40

No Evening 46 ≤35

Night-time 39 ≤30

NM06

Daytime 50 ≤40

No Evening 49 ≤35

Night-time 36 ≤30

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Location Period Average

LA90,15iin (dB)

NG4 Screening (dB LA90,15min)

Satisfies All Criteria for Low Background

Noise Area?

NM07

Daytime 49 ≤40

No Evening 46 ≤35

Night-time 36 ≤30

NM08

Daytime 33 ≤40

No Evening 40 ≤35

Night-time 38 ≤30

Table 14 Comparison of Measurement Results with NG4 Low Background Noise Area Criteria

As outlined in Table 4, none of the locations would be considered ‘Areas of Low Background Noise’ as the measured noise levels do not satisfy the criteria.

4.4 Determining Appropriate Noise Criteria Based on the EPA NG4 guidance the following noise criteria are appropriate at the nearest NSL’s to the facility:

• Daytime (07:00 to 19:00hrs) 55dB LAr,15min

• Evening (19:00 to 23:00hrs) 50dB LAr,15min

• Night time (23:00 to 07:00hrs) 45dB LAeq,15min

During the night period, no tonal or impulsive noise from the facility should be clearly audible or measurable at any NSL. The applicable noise criteria identified are in line with the typical limit values for noise from licensed sites. There are some plant items proposed for the development site that are designed to be used in emergency situations, for example, when grid power supplies fail. It is common practice to allow a relaxation of noise limits associated with emergency plant operations. Section 4.4.1 of EPA NG4 contains the following comments in relation to emergency plant items:

“In some instances, licensed sites will have certain items of emergency equipment (e.g. standby generators) that will only operate in urgent situations (e.g. grid power failure). Depending upon the context, it may be deemed permissible for such items of equipment to give rise to exceedances in the noise criteria/limits during limited testing and emergency operation only. If such equipment is in regular use for any purposes other than intermittent testing, it is subject to the standard limit values for the site”.

It is therefore considered that the proposed noise criterion of 55dB LAeq,(15mins) is appropriate in emergency scenarios for daytime, evening and night-time periods. These are in line with the current licence conditions that the existing site operates under.

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4.5 Compliance Noise Monitoring

See Attachment 7.5 of the Licence application for further details on the noise sensitive locations. Given there may be potential access constraints at some noise sensitive locations and the presence of extraneous noise sources in the vicinity, it is may be necessary to undertake compliance noise monitoring (if required) at the site boundary or at a suitable proxy location and assess to the nearest NSL’s. Any such assessment should be undertaken in accordance with the guidance outlined in the EPA NG4 document and supported by a sufficiently detailed noise report outlining the calculation methods used to determine the noise emission levels at the NSL’s.

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5.0 ASSESSMENT

This section deals with ‘Stage 3’ of the noise impact assessment as outlined in the EPA’s NG4 Guidance.

The noise levels expected at nearest NSL’s, due to the operation of the facility, must be considered and presented as part of the licence application. The following sections present details of the assessment and the findings. Further information in relation to the noise prediction model, inputs, calculation settings and assessment assumptions are provided in Appendix B. It should be noted that noise impact assessment has been completed using information obtained from the design team for significant items of plant which are currently being procured from vendors.

5.1 Noise Sensitive Locations

Noise prediction calculations have been carried out at the representative nearest noise sensitive locations (NSL’s) surrounding the site. Details of the NSL’s used for the prediction calculations are presented in Table 15. Free field noise emission levels have been predicted at a height stated in Table 15.

Noise Sensitive Location

Calculation Height (m) National Grid Reference

North East

NSR-01 1.6 298,309 236,892

NSR-02 1.6 297,958 236,991

NSR-03 3.8 297,905 236,999

NSR-04 1.6 297,947 236,971

NSR-05 1.6 297,243 237,215

NSR-06 1.6 297,857 237,513

NSR-07 1.6 297,770 237,517

NSR-08 1.6 297,605 237,655

NSR-09 1.4 297,971 237,725

NSR-10 1.6 297,662 238,071

NSR-11 1.6 297,795 238,055

NSR-12/13 1.6 297,920 238,066

NSR-14 1.6 298,078 237,760

NSR-15 1.6 298,415 237,777

NSR-16 1.6 298,485 237,779

NSR-17 1.6 298,592 237,739

NSR-18 1.4 298,677 237,711

NSR-19 4 298,695 237,957

NSR-20 4 298,769 237,926

NSR-24-28 4 299,089 237,822

NSR29-49 3.8 299,606 237,748

NSR50 1.6 297,047 237,480

Table 15 Coordinates of Noise Sensitive Receivers

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5.2 Noise Source Data Details of the major proposed sources of noise on the site and existing sources associated with the site are available on request. Note that the modelling presented here considers the major day to day operational noise sources that are located on the site. Certain minor noise sources, e.g. pumps associated with water tanks, etc, are not included in the noise model as they are not a material issue in terms of off site noise impacts. The main potential noise-related element of the facility is, as is the case for the current Intel site, process machinery and mechanical services plant. The various operations associated with the overall proposed facility contain boilers, air compressors, cooling towers, exhaust stacks and pumps etc. Other potential noise sources include additional traffic movements on public roads and car parking on site. The noise and vibration controls built into the design are summarised as follows:

• All major exhaust fans to incorporate attenuators to fan outlets.

• Oil Free Air (OFA) Stacks to be directed South.

• All barrier walls were modelled as shown in the latest model information provided by Jacobs, including full perimeter barrier walls around the rooftop exhaust Abatement areas on the roof and barrier walls around three sides of the exhaust fans located above the Acid Waste Neutralization (AWN).

• The visual screen wall along the northwest corner of the site adjacent to Ammonia Waste (NH4W) and Trimix equipment is assumed to be at least 3 meters tall and solid down to ground level

• Acoustic barrier around four sides of the Boiler Chiller Plant (BCP) Roof raised to a minimum height of 2.0m above the top of the Cooling Towers.

• Additional attenuation to cooling tower air intakes in order to reduce the sound power Level at intake to ≤84dB LwA.

• All barriers except the northwest visual screen wall referenced above are required to incorporate absorption on the inner face (i.e. toward the noise sources)

• Provide acoustical enclosures on the fan motors and acoustical lagging around the fan scroll casing for the Extract Fans, Exhaust General Building and Solvent Exhaust exhaust fans on the roof, as well as the Scrubbed Exhaust, Ammonia Exhaust, and Gas Pad exhaust fans.

• Provision of duct lagging (min 10kg/m2) to the large exhaust ducts connected to the EF132 and EF138 fans on the fab roof, along with the EF133 ductwork above the AWN areas.

5.3 Calculation Methodology

This assessment has been completed using a detailed computer-based noise model that has been prepared by AWN using proprietary noise modelling software package, Brüel & Kjær Predictor Type 7810. All noise prediction calculations have been carried out in accordance with ISO 9613-2:1996 Acoustics -- Attenuation of sound during propagation outdoors -- Part 2: General method of calculation. This is the preferred calculation methodology as stated in the NG4 Guidance and in this instance, due to the number of noise sources and distances to the nearest NSL’s, it is considered the most appropriate assessment method.

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This method has the scope to consider a range of factors affecting sound propagation, including:

• the magnitude of the noise source in terms of sound power;

• the distance between the source and receiver;

• the presence of obstacles such as screens or barriers in the propagation path;

• the presence of reflecting surfaces;

• the hardness of the ground between the source and receiver;

• attenuation due to atmospheric absorption, and;

• meteorological effects such as wind gradient, temperature gradient, humidity (these can have significant impact at distances greater than approximately 400m).

5.4 Predicted Noise Levels

This section presents the predicted noise levels at the nearest noise sensitive locations. It should be noted that as a worst case it is assumed that the new plant (except emergency items) are operating continuously during daytime, evening and night periods for normal operation. Figure 5 presents the predicted noise contour plot for mechanical services and process plant associate with the development at a calculation height of 4m above ground level. The predicted noise levels from new mechanical plant at each NSL are tabulated in Table 16.

Location Plant Predicted Level (dB)

NSR-01 38

NSR-02 43

NSR-03 43

NSR-04 41

NSR-05 36

NSR-06 43

NSR-07 39

NSR-08 38

NSR-09 45

NSR-10 39

NSR-11 27

NSR-12/13 40

NSR-14 44

NSR-15 45

NSR-16 45

NSR-17 44

NSR-18 43

NSR-19 42

NSR-20 42

NSR-24-28 41

NSR29-49 39

NSR50 31

Table 16 Predicted Operational Noise Levels at NSL’s for New Mechanical Plant Items

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Table 17 present the predicted plant noise emission levels at the nearest NSL’s and compares the results against the relevant criteria that have been derived for the site.

Receptor Predicted LAeq,15min

Day (07:00 – 19:00hrs)

Evening (19:00 – 23:00hrs)

Night (23:00 – 07:00hrs)

Criterion dB LAr,T

Co

mp

lies?

Criterion dB LAr,T

Co

mp

lies?

Criterion dB LAeq,T

Co

mp

lies?

NSR-01 38

55

Yes

50

Yes

45

Yes

NSR-02 43 Yes Yes Yes










NSR-12/13 40 Yes Yes Yes








NSR-24-28 41 Yes Yes Yes

NSR29-49 39 Yes Yes Yes

NSR50 31 Yes Yes Yes

Table 17 Predicted Operational Noise Levels vs Criteria

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Figure 4 Noise Prediction Locations

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Figure 5 Operational Noise Prediction Contours

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6.0 CONCLUSION

A detailed noise survey has been completed at eight noise sensitive locations surrounding the site to establish the existing noise environment. This work has demonstrated that the existing noise environment is dictated by steady plant noise emissions from the operation of the existing facility and road traffic noise. In accordance with the relevant NG4 Guidance, appropriate operational noise criteria have been derived for the site which are based on consideration of the existing licence noise conditions and the existing noise environment at the nearest NSL’s. A noise impact assessment has been completed using information obtained from the design team for significant items of new mechanical plant. A detailed computer-based noise model has been prepared using proprietary noise modelling software in accordance with the calculation method outlined in ISO 9613-2:1996. The predicted noise levels at all NSL’s are below the day, evening and night-time noise criteria that are applicable to the site operations. Confirmation will be sought from the relevant suppliers at the detailed design stage that any significant noise producing plant items shall not emit tonal or impulsive characteristics to such a degree, that these characteristics could be audible at the noise sensitive locations. It should be noted that this preliminary noise impact assessment has been completed using information obtained from the design team for significant items of plant which are currently being procured from vendors. It is anticipated that where there is any substantial variation in the noise emission level of plant when installed on site (i.e. that has not been accounted for in the data used for this assessment), additional noise control measures such as, acoustic barriers or attenuator systems will be employed where necessary, to ensure that the operation of the facility will comply with the required noise criteria set out in this report or defined in the Licence issued to the operator.

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APPENDIX A GLOSSARY OF ACOUSTIC TERMINOLOGY

ambient noise The totally encompassing sound in a given situation at a given

time, usually composed of sound from many sources, near and far.

background noise The steady existing noise level present without contribution from

any intermittent sources. The A-weighted sound pressure level of the residual noise at the assessment position that is exceeded for 90 per cent of a given time interval, T (LAF90,T).

broadband Sounds that contain energy distributed across a wide range of

frequencies. dB Decibel - The scale in which sound pressure level is expressed.

It is defined as 20 times the logarithm of the ratio between the RMS pressure of the sound field and the reference pressure of 20 micro-pascals (20 μPa).

dB LpA An ‘A-weighted decibel’ - a measure of the overall noise level of

sound across the audible frequency range (20 Hz – 20 kHz) with A-frequency weighting (i.e. ‘A’–weighting) to compensate for the varying sensitivity of the human ear to sound at different frequencies.

Hertz (Hz) The unit of sound frequency in cycles per second. impulsive noise A noise that is of short duration (typically less than one second),

the sound pressure level of which is significantly higher than the background.

LAeq,T This is the equivalent continuous sound level. It is a type of

average and is used to describe a fluctuating noise in terms of a single noise level over the sample period (T).The closer the LAeq value is to either the LAF10 or LAF90 value indicates the relative impact of the intermittent sources and their contribution. The relative spread between the values determines the impact of intermittent sources such as traffic on the background.

LAFN The A-weighted noise level exceeded for N% of the sampling

interval. Measured using the “Fast” time weighting. LAFmax is the instantaneous slow time weighted maximum sound level

measured during the sample period (usually referred to in relation to construction noise levels).

LAr,T The Rated Noise Level, equal to the LAeq during a specified time

interval (T), plus specified adjustments for tonal character and impulsiveness of the sound.

LAF90 Refers to those A-weighted noise levels in the lower 90

percentile of the sampling interval; it is the level which is exceeded for 90% of the measurement period. It will therefore exclude the intermittent features of traffic and is used to estimate a background level. Measured using the “Fast” time weighting.

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APPENDIX A GLOSSARY OF ACOUSTIC TERMINOLOGY (Continued)

LAT(DW) equivalent continuous downwind sound pressure level. LfT(DW) equivalent continuous downwind octave-band sound pressure

level. low frequency noise LFN - noise which is dominated by frequency components

towards the lower end of the frequency spectrum. noise Any sound, that has the potential to cause disturbance,

discomfort or psychological stress to a person exposed to it, or any sound that could cause actual physiological harm to a person exposed to it, or physical damage to any structure exposed to it, is known as noise.

noise sensitive location NSL – Any dwelling house, hotel or hostel, health building,

educational establishment, place of worship or entertainment, or any other facility or other area of high amenity which for its proper enjoyment requires the absence of noise at nuisance levels.

octave band A frequency interval, the upper limit of which is twice that of the

lower limit. For example, the 1,000Hz octave band contains acoustical energy between 707Hz and 1,414Hz. The centre frequencies used for the designation of octave bands are defined in ISO and ANSI standards.

rating level See LAr,T. sound power level The logarithmic measure of sound power in comparison to a

referenced sound intensity level of one picowatt (1pW) per m2 where:

0

10P

PLogLw = dB

Where: p is the rms value of sound power in pascals; and

P0 is 1 pW. sound pressure level The sound pressure level at a point is defined as:

0

20P

PLogLp = dB

specific noise level A component of the ambient noise which can be specifically

identified by acoustical means and may be associated with a specific source. In BS 4142, there is a more precise definition as follows: ‘the equivalent continuous A-weighted sound pressure level at the assessment position produced by the specific noise source over a given reference time interval (LAeq, T)’.

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APPENDIX A GLOSSARY OF ACOUSTIC TERMINOLOGY (Continued)

tonal Sounds which cover a range of only a few Hz which contains a

clearly audible tone i.e. distinguishable, discrete or continuous noise (whine, hiss, screech, or hum etc.) are referred to as being ‘tonal’.

1/3 octave analysis Frequency analysis of sound such that the frequency spectrum is

subdivided into bands of one–third of an octave each.

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APPENDIX B NOISE MODEL & IMPACT ASSESSMENT DETAILS

B.1.1 Noise Sensitive Locations Table B.1 presents the location of the various noise sensitive locations (NSL’s)

identified for the noise impact assessment.

Noise Sensitive Location

Calculation Height (m) National Grid Reference

North East

NSR-01 1.6 298,309 236,892

NSR-02 1.6 297,958 236,991

NSR-03 3.8 297,905 236,999

NSR-04 1.6 297,947 236,971

NSR-05 1.6 297,243 237,215

NSR-06 1.6 297,857 237,513

NSR-07 1.6 297,770 237,517

NSR-08 1.6 297,605 237,655

NSR-09 1.4 297,971 237,725

NSR-10 1.6 297,662 238,071

NSR-11 1.6 297,795 238,055

NSR-12/13 1.6 297,920 238,066

NSR-14 1.6 298,078 237,760

NSR-15 1.6 298,415 237,777

NSR-16 1.6 298,485 237,779

NSR-17 1.6 298,592 237,739

NSR-18 1.4 298,677 237,711

NSR-19 4 298,695 237,957

NSR-20 4 298,769 237,926

NSR-24-28 4 299,089 237,822

NSR29-49 3.8 299,606 237,748

NSR50 1.6 297,047 237,480

Table B.1 Details of Noise Sensitive Locations

B.1.2 Noise Model A 3D computer-based prediction model has been prepared to quantify the operational

noise emission levels from proposed development. This section discusses the methodology behind the noise modelling and noise impact assessment process.

B.1.3 Brüel & Kjær Predictor Type 7810 Proprietary noise calculation software has been used for the purposes of this

modelling exercise. The selected software package was Brüel & Kjær Predictor Type 7810, this package calculates noise levels in accordance with ISO 9613: Acoustics – Attenuation of sound during propagation outdoors, Part 2: General method of calculation, 1996.

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Predictor is a proprietary noise calculation package for computing noise level propagation from a range of noise source types. Predictor calculates noise levels in different ways depending on the selected prediction standard. In general, however, the resultant noise level is calculated considering a range of factors affecting the propagation of sound, including: • the magnitude of the noise source in terms of A weighted sound power levels

(LWA); • the distance between the source and receiver; • the presence of obstacles such as screens or barriers in the propagation path; • the presence of reflecting surfaces; • the hardness of the ground between the source and receiver; • Attenuation due to atmospheric absorption; and • Meteorological effects such as wind gradient, temperature gradient and

humidity (these have significant impact at distances greater than approximately 400m).

B.1.4 Brief Description of ISO9613-2: 1996

ISO 9613-2:1996 calculates the noise level based on each of the factors discussed previously. However, the effect of meteorological conditions is significantly simplified by calculating the average downwind sound pressure level, LAT(DW), for the following conditions:

• wind direction at an angle of ±45° to the direction connecting the centre of the dominant sound source and the centre of the specified receiver region with the wind blowing from source to receiver, and;

• wind speed between approximately 1ms-1 and 5ms-1, measured at a height of 3m to 11m above the ground.

The equations and calculations also hold for average propagation under a well-developed moderate ground based temperature inversion, such as commonly occurs on clear calm nights. The basic formula for calculating LAT(DW) from any point source at any receiver location is given by:

LfT(DW) = LW + Dc – A Equation A Where: LfT(DW) is an octave band centre frequency component of LAT(DW) in dB relative to

2x10-5Pa; LW is the octave band sound power of the point source; Dc is the directivity correction for the point source; A is the octave band attenuation that occurs during propagation, namely

attenuation due to geometric divergence, atmospheric absorption, ground effect, barriers and miscellaneous other effects.

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The estimated accuracy associated with this methodology is shown in Table B.2 below:

Height, h* Distance, d†

0 < d < 100m 100m < d < 1,000m

0<h<5m ±3dB ±3dB

5m<h<30m ±1dB ±3dB

Table B.2 Estimated Accuracy for Broadband Noise of LAT(DW) * h is the mean height of the source and receiver. † d is the mean distance between the source and receiver. N.B. These estimates have been made from situations where there are no effects due to

reflections or attenuation due to screening.

B.1.5 Input Data and Assumptions

The noise model has been compiled using data from various sources as follows: Site Layout The general site layout has been obtained from the drawings

forwarded by Intel and Jacobs Engineering. Local Area The location of noise sensitive locations has been obtained from

review of Ordinance Survey Ireland (OSI) maps and online mapping applications (e.g. Google Earth) and on-site observations.

Heights Onsite building heights have been obtained from the drawings

forwarded from Jacobs Engineering. The assessment considers all the major and minor noise sources of plant items that have been identified as having the potential to emit noise beyond the site boundary. The details and location of all noise emission points and associated noise source data has been provided in Appendix C and D of this document. It should be noted that noise impact assessment has been completed using information obtained from the design team for significant items of plant which are currently being procured from vendors.

B.1.6 Modelling Calculation Parameters The atmospheric attenuation outlined in Table B.3 has been assumed for all

calculations.

Temp (ºC)

% Humidity

Octave Band Centre Frequencies (Hz)

63 125 250 500 1k 2k 4k 8k

10 80 0.11 0.38 1.02 1.97 3.57 8.76 28.72 103.21

Table B.3 Atmospheric Attenuation Assumed for Noise Calculations (dB per km)

Prediction calculations for noise emissions have been conducted in accordance with ISO 9613: Acoustics – Attenuation of sound during propagation outdoors, Part 2: General method of calculation, 1996. The following are the main aspects that have been considered in terms of the noise predictions presented in this instance.

Directivity Factor: The directivity factor (D) allows for an adjustment to be

made where the sound radiated in the direction of interest is higher than that for which the sound power level is specified. In this case the sound power level is

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calculated in a down wind direction, corresponding to the worst-case propagation conditions and needs no further adjustment. All noise sources have been assumed omni directional as a worst case with the exception of AHU penthouse louvres and boiler stack where a realistic directivity factor has been incorporated into the calculations.

Ground Effect: Ground effect is the result of sound reflected by the

ground interfering with the sound propagating directly from source to receiver. The prediction of ground effects are inherently complex and depend on source height receiver height propagation height between the source and receiver and the ground conditions. The ground conditions are described according to a variable defined as G, which varies between 0.0 for hard ground (including paving and concrete) and 1.0 for soft ground (includes ground covered by grass trees or other vegetation) Our predictions have been carried out using various source height specific to each plant item, a receiver height of 4m for a two-story development. A ground factor of G = 0.3 has been applied in general in the noise prediction model.

Geometrical Divergence: This term relates to the spherical spreading in the free-

field from a point sound source resulting in attenuation depending on distance according to the following equation:

Ageo = 20 x Log(distance from source in meters) + 11

Atmospheric Absorption: Sound propagation through the atmosphere is

attenuated by the conversion of the sound energy into heat. This attenuation is dependent on the temperature and relative humidity of the air through which the sound is travelling and is frequency dependent with increasing attenuation towards higher frequencies. In these predictions a temperature of 10°C and a relative humidity of 80% have been used, which give relativity low levels of atmosphere attenuation and corresponding worst case noise predictions.

Barrier Attenuation: The effect of any barrier (or building) between the

noise source and the receiver position is that noise will be reduced according to the relative heights of the source, receiver and barrier and the frequency spectrum of the noise.

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B.1.7 Source Sound Power Data

Details of the major proposed sources of noise on the site and existing sources associated with the site are available on request. Note that the modelling presented here considers the major day to day operational noise sources that are located on the site. Certain minor noise sources, e.g. pumps associated with water tanks, etc, are not included in the noise model as they are not a material issue in terms of off site noise impacts.

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noise modelling report · 2020. 4. 25. · dk/19/11051nr01 awn consulting limited _____ _____ page...

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noise modelling report · 2020. 4. 25. · dk/19/11051nr01 awn consulting limited _ _ page...