PROPOSED CO-OPERATIVE SUPERMARKET, KNIGHTON

Transcription

1 REPORT N O PROPOSED CO-OPERATIVE SUPERMARKET, KNIGHTON NOISE IMPACT ASSESSMENT MAY 2016

2 PROPOSED CO-OPERATIVE SUPERMARKET, KNIGHTON NOISE IMPACT ASSESSMENT The Mid-Counties Co-Operative Final Project no: Date: The Victoria, The Quays, Salford, Greater Manchester, M50 3SP Tel: +44 (0)

3 QUALITY MANAGEMENT ISSUE/REVISION FIRST ISSUE REVISION 1 REVISION 2 REVISION 3 Remarks Final Date 09/05/2016 Prepared by Adam Barr Signature Checked by Jordan Mayes Signature Authorised by James Powlson Signature Project number Report number 001 File reference \\uk.wspgroup.com\central data\projects\700206xx\ Proposed Supermarket, Knighton\C Documents\Report\Proposed Supermarket, Knighton Noise Impact Assessment

4 ii PRODUCTION TEAM Client The Mid-Counties Co-Operative 46 Westward Road, Cainscross, Stroud, Gloucestershire, GL5 4JG Consultant The Victoria The Quays Manchester M50 3SP UK Tel: +44 (0) Registered Address WSP UK Limited WSP House, 70 Chancery Lane, London, WC2A 1AF WSP Contacts Adam Barr Senior Acoustic Consultant Tel: +44 (0)

5 iii TABLE OF CONTENTS 1 INTRODUCTION PROJECT BACKGROUND LEGISLATION AND GUIDANCE BASELINE NOISE SURVEY MEASUREMENT RESULTS NOISE SOURCE DATA ACOUSTIC MODELLING ASSESSMENT CONCLUSIONS...14 Mid-Counties Co-Operative Project No

6 1 1 INTRODUCTION have been appointed by The Mid-Counties Co-Operative to undertake a noise impact assessment to support an outline planning application for a proposed supermarket and petrol station development in Knighton, Powys The site currently comprises an existing Harry Tuffins supermarket, petrol station and associated multi-storey car park. It is proposed that the existing facilities be demolished and replaced with the proposed development The noise assessment has been undertaken following guidance contained within a number of appropriate documents such as British Standard 4142:2014: Methods for rating and assessing industrial and commercial sound, British Standard 8233:2014: Guidance on sound insulation and noise reduction for buildings, and the requirements of Powys County Council s Environmental Health Department This report is necessarily technical in nature, so to assist the reader a glossary of acoustic terminology is included in Appendix A. 2 PROJECT BACKGROUND 2.1 SITE DESCRIPTION The development is proposed to replace the existing Harry Tuffins Supermarket in the centre of Knighton. The site is bounded by Bridge Street to the west, residential dwellings and a restaurant and takeaway to the north, Bowling Green Lane to the south and a livestock market to the east. Beyond Bridge Street and Bowling Green Lane to the west and south respectively are existing residential dwellings A drawing detailing a redline site boundary and the location of the existing store is included in Appendix B DEVELOPMENT PROPOSALS The development is to comprise a new supermarket in the northern portion of the site, with the associated service yard in the northeast corner, a petrol station in the southern section of the site and car park in the centre of the site surrounding the other elements A drawing detailing the proposed scheme layout is included in Appendix C The proposed store opening hours and delivery times are: Supermarket Store: 07:00 to 22:00 hours Monday to Saturday 10:00 to 16:00 hours on Sundays and bank holidays Deliveries:

7 2 07:00 to 21:00 hours everyday From the information provided by The Mid-Counties Co-Operative, it is understood that the following deliveries will occur on a weekly basis. Table 1: Proposed Convenience Store Deliveries PRODUCT VEHICLE NUMBER PER WEEK Ambient Articulated vehicle (HGV) 4 Fresh (refrigerated HGV) Articulated vehicle (HGV) In addition to the above it is understood that there could be up to three fuel tanker deliveries to the proposed petrol station per week. 3 LEGISLATION AND GUIDANCE 3.1 CONSULTATION At the outset of the project consultation was undertaken with the dealing Environmental Health Officer at Powys County Council in order to agree the survey methodology. Following completion of the baseline noise survey further consultation was undertaken in order to agree the assessment methodology to be adopted for this noise impact assessment. Specifically the following survey and assessment methodologies were agreed. SURVEY METHODOLOGY Due to site security limitations, a number of attended measurements would be undertaken to determine the background noise levels at the nearest noise sensitive receptors, during the quietest periods of the day and night Roving measurements would be undertaken at three measurement locations (labelled in Appendix B) for a duration of 15-minutes between the hours of 22:00 23:00 (the quietest daytime period), 02:00 3:00 (quietest night-time period) and 06:00 07:00 (end of nighttime/start of daytime period) These measurements would be used to determine background noise levels (L A90,T ) in order to facilitate an assessment in accordance with BS 4142 and ambient noise levels (L Aeq,T ) to allow a comparison of absolute noise levels.

8 3 ASSESSMENT METHODOLOGY PLANT NOISE ASSESSMENT Noise emissions from proposed fixed plant items should be assessed in accordance with BS 4142:2014: Methods for rating and assessing industrial and commercial sound. As the details of the specific plant items will not be known until detailed design stage, plant noise emission limits will be set in terms of rating levels, as defined in accordance with BS 4142, equal to the prevailing background noise level for typical daytime and night-time periods. DELIVERY NOISE ASSESSMENT Noise level predictions should be undertaken to establish the noise levels that will be generated by HGV movements to and from the proposed delivery area and petrol station, at the closest dwellings. The predictions should be undertaken to reflect the anticipated HGV movements to and from the site with consideration to the number, regularity and timing of such events The predicted noise levels associated with the delivery vehicle unloading area and petrol station deliveries would be assessed in accordance with BS 4142, drawing on the results of the baseline noise survey Where significant impacts are identified to arise from the delivery vehicle unloading area or deliveries to the petrol station, an appraisal of suitable generic mitigation measures should be undertaken, where this is deemed necessary. OPERATIONAL NOISE FROM CAR PARK ACTIVITIES A series of noise level predictions should be undertaken in order to predict the noise levels generated at local dwellings as a result of customers and staff using the proposed car park. These noise level predictions should include for contributions from existing noise sources in the vicinity of the site such as road traffic noise in order to determine the resulting ambient noise levels with the scheme in operation. The predicted noise levels should then be compared against the internal and external noise level criteria from BS 8233:2014, in order to determine whether appropriate noise levels would be achieved at local receptors with the scheme in operation Where significant impacts are identified to arise from use of the car park, we should conduct an appraisal of suitable generic mitigation measures. 3.2 BS 8233:2014: GUIDANCE ON SOUND INSULATION AND NOISE REDUCTION FOR BUILDINGS This standard provides guidance for the control of noise in and around buildings. The guidance provided within the document is applicable to the design of new buildings, or refurbished buildings undergoing a change of use, but does not provide guidance on assessing the effects of changes in the external noise levels to occupants of an existing building The guidance provided includes appropriate internal and external noise level criteria which are applicable to dwellings exposed to steady external noise sources. It is stated in the British Standard that it is desirable for internal ambient noise level not to exceed the criteria set out in Table 2 below:

9 4 Table 2: Summary of internal ambient noise level criteria for habitable rooms from BS 8233:2014 PERIOD ACTIVITY LOCATION 07:00 TO 23:00 HOURS, I.E. DAYTIME 23:00 TO 07:00 HOURS, I.E. NIGHT- TIME Resting Living Room 35 db L Aeq, 16 Hour - Dining Dining Room/area 40 db L Aeq, 16 Hour - Sleeping (daytime resting) Bedroom 35 db L Aeq, 16 Hour 30 db L Aeq, 8 Hour With respect to external amenity space such as gardens and patios, it is stated that it is desirable that the noise level does not exceed 50 db L Aeq,T, with an upper guideline value of 55 db L Aeq,T which would be acceptable in noisier environments. BRITISH STANDARD 4142: 2014: METHODS FOR RATING AND ASSESSING INDUSTRIAL AND COMMERCIAL SOUND (BS 4142) British Standard 4142 describes methods for rating and assessing the following: Sound from industrial and manufacturing processes; Sound from fixed installations which comprise mechanical and electrical plant and equipment; Sound from the loading and unloading of goods and materials at industrial and/or commercial premises; and Sound from mobile plant and vehicles that is an intrinsic part of the overall sound emanating from premises or processes, such as that from forklift trucks, or that from train movements on or around an industrial and/or commercial site The methods use outdoor sound levels to assess the likely effects of sound on people who might be inside or outside a dwelling or premises used for residential purposes upon which sound is incident In accordance with the assessment methodology, the specific sound level (L Aeq,T ) of the noise source being assessed is corrected through the application corrections for acoustic features, such as tonal qualities and/or distinct impulses, to give a rating level (L Ar,Tr ).The British Standard effectively compares and rates the difference between the rating level and the typical background sound level (L A90,T ) in the absence of the noise source being assessed The British Standard advises that the time interval ('T') of the background sound measurement should be sufficient to obtain a representative or typical value of the background sound level at the time(s) when the noise source in question is likely to operate or is proposed to operate in the future Comparing the rating level with the background sound level, BS 4142 states: Typically, the greater this difference, the greater the magnitude of impact.

10 5 A difference of around +10 db or more is likely to be an indication of a significant adverse impact, depending on the context. A difference of around +5 db is likely to be an indication of an adverse impact, depending on the context. The lower the rating level is relative to the measured background sound level, the less likely it is that the specific sound source will have an adverse impact or a significant adverse impact. Where the rating level does not exceed the background sound level, this is an indication of the specific sound source having a low impact, depending on the context In order to inform an assessment based on the guidance contained within the above standards, a baseline noise survey has been conducted on the site, as detailed in the following section. 4 BASELINE NOISE SURVEY To inform the assessment, a baseline environmental noise survey was undertaken at locations representative of the closest noise sensitive receptors to the site. This survey was undertaken in order to determine the existing ambient and background noise levels present at these receptors and was conducted between the 31 st March and the 01 st April MEASUREMENT LOCATIONS Noise measurements were taken at three monitoring locations considered to be representative of the closest existing noise sensitive receptors. The measurement locations, depicted in Appendix B, are as follows: Measurement Location 1 Adjacent to properties on Bowling Green Lane to the south of the development site, at a height of 1.5 m above local ground. This measurement location was used to determine the current noise environment experienced by dwellings on Bowling Green Lane during the quietest periods of the daytime and night-time. Measurement Location 2 Adjacent to properties on Bridge Street to the west of the development site, at a height of 1.5 m above local ground. This measurement location was used to establish the noise environment experienced by dwellings on Bridge Street during the quietest periods of the daytime and night-time. Measurement Location 3 Adjacent to properties on Swan Court to the north of the site, at a height of 1.5 m above local ground. This measurement location was used to establish the noise levels experienced by the dwellings on Swan Court for a continuous period between approximately 18:00 on the 31 st March and 12:00 on the 1 st April. 4.3 METEOROLOGICAL CONDITIONS Over the course of the baseline noise survey, meteorological conditions remained conducive to environmental noise measurement remaining dry with negligible wind speeds MEASUREMENT EQUIPMENT The baseline noise survey measurements were undertaken using the following Class 1 specification noise measuring equipment:

11 6 Table 3: Noise Measurement Equipment MEASUREMENT LOCATION EQUIPMENT MAKE AND MODEL SERIAL NUMBER CALIBRATION DUE DATE 1 and 2 Sound Level Meter 01dB-METRAVIB Solo Master th July 2016 Pre-amplifier 01dB-Stell PRE 21 S Microphone Microtech Gefell GmbH MCE Sound Level Meter 01 db-metravib DUO nd September 2017 Pre-amplifier 01 db Metravib PRE Microphone GRAS 40CD The sound level meters had been calibrated to traceable standards within the preceding two years and the portable calibrator within the preceding 12 months. The sound level meters were calibrated both prior to and upon completion of the survey. No significant drift was noted. 5 MEASUREMENT RESULTS A summary of the noise levels measured at the measurement locations 1 to 3 are presented within Table 4 below. Table 4: Summary of Noise Measurement Results, Free-field db MEASUREMENT LOCATION PERIOD DURATION (HH:MM) MEASURED BACKGROUND NOISE LEVEL (L A90,T ) MEASURED AMBIENT NOISE LEVEL (L Aeq,T ) 1 22:05-22:20 00: :23-22:38 00: :59 02:14 00: :16 02:31 00: :34 06:49 00: :50 07:05 00: Daytime 11:

12 7 MEASUREMENT LOCATION PERIOD DURATION (HH:MM) MEASURED BACKGROUND NOISE LEVEL (L A90,T ) MEASURED AMBIENT NOISE LEVEL (L Aeq,T ) 3 Night-time 8: The meter logged between 19:00 on the 31 st March and 11:00 on the 1 st April. The stated L A90,T is the average of all L A90,1h periods, during the daytime, between the start and end times. 2 The meter logged between 19:00 on the 31 st March and 11:00 on the 1 st April. The stated L Aeq,T is derived from all periods within the daytime period (23:00 07:00) between the start and end times During attended periods on site, the main noise sources at Measurement Locations 1 and 2 were found to be road traffic on Bridge Street during the daytime and fixed plant items associated with the Harry Tuffins Supermarket during the night-time period. At Measurement Location 3 the main noise sources were noted to be traffic on Bridge Street and fixed plant items associated with the restaurant and takeaway to the north of the site during the daytime, the fixed plant items associated with the restaurant were not operational between 22:00 and 08:00, during these periods distant industrial and road traffic noise sources were dominant. The night-time period was therefore not adversely affected by the fixed plant associated with the restaurant. 6 NOISE SOURCE DATA Calculations have been undertaken to quantify and assess the likely noise impacts of loading and unloading activities in the service yard area at the closest noise sensitive receptors. The calculations have been based on source noise data of delivery activities selected from the WSP Parsons Brinckerhoff library of historical measurement data which were collected during surveys undertaken at existing operational stores. Such activities included the starting and departure of a refrigerated HGV, along with the arrival, unloading and departure of a HGV Calculations have also been undertaken to quantify and assess the likely noise impacts of operations associated with the proposed customer car park at the closest noise sensitive receptors. The calculations have been based on source noise data of car parking activities from the library of historical measurement data. Such activities include cars manoeuvring into parking spaces, car doors slamming, car engines being started, cars manoeuvring out of parking spaces and cars pulling away A summary of the source noise data for the delivery and service yard activities and customer car park operations are presented within Tables 5 and 6 respectively. Table 5: Noise Data HGV Delivery Noise, Free-field ACTIVITY SEL (L AE ) NORMALISED TO 5M FROM SOURCE (db) 1 DURATION OF ACTIVITY FOR SINGLE EVENT (SECONDS) 2 NUMBER OF EVENTS PER HOUR HGV Refrigeration unit on HGV Refrigeration unit

13 8 ACTIVITY SEL (L AE ) NORMALISED TO 5M FROM SOURCE (db) 1 DURATION OF ACTIVITY FOR SINGLE EVENT (SECONDS) 2 NUMBER OF EVENTS PER HOUR & vehicle engine on Refrigerated HGV departing HGV arrival and manoeuvring Unloading using forklift (HGV engine off) HGV shutter closing (HGV engine off) HGV start-up and departure Total service yard noise level L Aeq,1h at 5m db (assuming all activities are ongoing for the duration stated above during a 1-hour period) HGV MOVEMENTS THROUGH THE SITE HGV passby 80 L AFmax at 5m db NOISE FROM FUEL TANKER DELIVERY Fuel tanker pumping 78 L Aeq,T at 5m db 1 Based on library data. 2 Accounting for anticipated number of events. Table 6: Noise Data Customer Car Park Operations, free-field ACTIVITY SEL (L AE ) NORMALISED TO 5M FROM SOURCE (db) 1 DURATION OF ACTIVITY FOR SINGLE EVENT (SECONDS) NUMBER OF EVENTS PER HOUR Car pass-bys Car door slams Engine starting/turn over Manoeuvring into and out of a space Pulling away Total SEL 87 2

14 9 ACTIVITY SEL (L AE ) NORMALISED TO 5M FROM SOURCE (db) 1 DURATION OF ACTIVITY FOR SINGLE EVENT (SECONDS) NUMBER OF EVENTS PER HOUR Total car park space noise level 1 Based on library data. 2 Accounting for anticipated number of events. 51 L Aeq,1h at 5 m Based on the above information a detailed acoustic model of the site has been generated to predict the noise levels at the nearest noise sensitive receptors. The prediction methodology is detailed in the following section. 7 ACOUSTIC MODELLING Drawing on the results of the baseline noise survey and the noise source data included in Tables 5 and 6, a detailed acoustic model of the site has been created to predict the level of noise generated by the proposed development at the nearest noise sensitive receptors, from car parking, deliveries/service yard operations during the daytime. Noise emissions from fixed plant items have not been included in the modelling exercise, as the exact items to be installed are not known at this stage, therefore noise level limits have been determined for noise emissions from these items. The model has been generated using CadnaA PC based noise modelling software. The following prediction methodologies have been adopted for the modelling exercise: The model was set up to apply the prediction methodology set out in the International Standard ISO : 1996: Acoustics Attenuation of sound during propagation outdoors Part 2: General method of calculation (ISO ) for the assessment of industrial/commercial noise sources. The model was set up to include second order reflected noise from solid structures. The level of noise generated by industrial/commercial noise sources have been modelled and calibrated based on the noise source data presented in Tables 5 and 6 modelled at appropriate locations for the noise sources being considered (e.g. the service yard for delivery related source, adjacent to the petrol station forecourt for the fuel tanker pumping and the car parking spaces for arrival and departure of customers). HGV movements through the site have been calculating assuming one HGV movement during a typical hour, travelling through the site at a speed of 10 km/h. The topography of the site has been calibrated based on the provided site and building elevation drawings. The model was set to include reflected noise from solid structures and buildings were modelled with an absorption coefficient of 0.2 (corresponding to a reduction of approximately 1 db per reflection) corresponding to Walls of building with windows and small additions or bay in accordance with Table 4 from ISO ; Off-site buildings which would provide screening to the site, have been incorporated with heights informed by observations made during the site visits and Street View online photography. The proposed supermarket buildings themselves have been modelled at a height of 8m based on the provided elevation drawings.

15 10 During the daytime periods the receiver height is taken as 1.5m above local ground (i.e. ground floor) and during the night-time the receiver height is taken as 4.0m (i.e. first floor height) for the BS 4142 assessment. For the assessment of internal ambient noise levels both 1.5 m and 4.0 m heights have been adopted for the daytime to account for daytime resting, during the night-time a height of 4.0 m has been adopted. Ground absorption was set to G = 0 (100% hard ground) to best reflect local ground cover When assessing noise emissions from service yard operations and deliveries in accordance with BS 4142, corrections were applied to the industrial/commercial noise sources to account for acoustic features. The fuel tanker deliveries were not included in the model created to assess typical noise levels, as fuel tanker deliveries would not occur during a typical hour. A separate assessment considering fuel tanker deliveries in isolation has been undertaken When assessing ambient noise levels in accordance with BS 8233:2014 no corrections were applied to the industrial/commercial noise sources, as these corrections (and the resulting rating levels) are not comparable to absolute internal and external noise level criteria from BS8233, which are stated as L Aeq values. 8 ASSESSMENT 8.1 ASSESSMENT OF AMBIENT NOISE LEVELS In order to assess the impact of noise from the operational noise sources associated with the site, a modelling exercise has been undertaken to predict the noise levels generated by use of the car parking spaces, vehicle movements associated with the proposed petrol station (excluding fuel deliveries) and deliveries to the supermarket service yard It is assumed that one vehicle delivery to the service yard will occur and that every car parking space will be used by three separate customers with each customer spending 20 minutes in the store during a typical hour. It is assumed that the HGV delivery to the service yard would follow the path outlined in Appendix C Based on the above assumptions and the prediction methodology outlined in section the noise levels generated by the site have been predicted at four assessment locations as labelled in Appendix D and as described below: Assessment Location A At the location of the closest façades of the closest properties on Swan Close. Assessment Location B At the location of the closest façade of properties on the western side of Bridge Street. Assessment Location C At the location of the closest façade of apartments on Bridge Street/Bowling Green Lane. In line with the proposed petrol filling station. Assessment Location D Adjacent to properties on Bowling Green Lane set further back from Bridge Street, opposite the proposed site access.

16 The internal noise levels at the nearest dwellings have also been calculated based on free-field external noise levels and a correction -15 db(a) through a partially open window as stated within BS 8233: Table 7 below details the predicted free-field noise levels at these receptors during the daytime period at 1.5m height and at 4.0m height. Table 7: Predicted daytime noise levels at Assessment Locations A D ASSESSMENT LOCATION HEIGHT PREDICTED EXTERNAL NOISE LEVEL L Aeq,1h PREDICTED INTERNAL NOISE LEVEL L Aeq,1h 1 A A B B C C D D Assuming a -15 db correction through a partially open window, as detailed BS The most stringent internal noise level criterion from BS 8233 for the daytime is 35 db(a), it can be seen from Table 7 that this noise level criterion is achieved by at least 1 db(a) from the development in isolation at all assessment locations. The absolute noise levels generated by the scheme during a typical hour achieve all relevant criteria and consideration to mitigation measures is not warranted It is not proposed that there will be any deliveries, use of the supermarket, use of the car park or petrol station during the night-time period (23:00-07:00), therefore an assessment of operational noise during the night-time period is not warranted. An assessment of noise of an industrial/commercial nature relative to the background noise levels on the site is included in the following section. 8.2 NOISE FROM FIXED PLANT AND SOURCES OF AN INDUSTRIAL NATURE The proposed supermarket store will inevitably incorporate a number of fixed mechanical and electrical plant items. It is anticipated that the fixed plant associated with the development will run 24 hours a day 7 days a week Details of any proposed plant, building services equipment, machinery or other sources of an industrial nature associated with the development are not currently known. In such instances, to ensure that the noise from such sources is not likely to result in adverse impacts at the nearby noise sensitive premises, it is appropriate to specify plant noise level limits.

17 Powys County Council have confirmed that the noise rating level from the development should ideally not exceed the existing background noise level at the nearby noise sensitive premises when assessed in accordance with BS 4142: It was noted during the baseline noise survey that fixed plant associated with the existing supermarket was clearly audible at the adopted measurement locations with the exception of Measurement Location 3, which was dominated by a mixture of distant road traffic noise and distant industrial sources. The background noise levels at Measurement Location 3 therefore represent the lowest measured background noise levels during the daytime and night-time period It is considered prudent to adopt the background noise levels from Measurement Location 3 for the assessment of impact at all nearby noise sensitive receptors to reduce the effects of noise from the existing supermarket development on the BS 4142 assessment Based on the above information Table 8 below provides the maximum permissible noise level limit at the nearby noise sensitive premises based upon the measured background noise levels as detailed in Table 4. Table 8 Maximum permissible BS 4142 noise level limits at nearby noise sensitive premises, taken from Measurement Location 3 PERIOD NOISE LEVEL LIMIT (L A90,T, db) Daytime 48 Night-time The total combined noise level of all proposed plant, building services equipment, machinery or other sources of industrial noise associated with the development will need to comply with the above limits. If any corrections for acoustic features are required to be applied in accordance with BS 4142, the appropriate corrections should be applied prior to comparison with the above limits Using the detailed noise model of the site, as described in Section 7, the noise levels generated by deliveries to the associated service yard have been calculated in order to compare the noise levels generated to the above limits. Including arrival of a refrigerated HGV and associated unloading operations in the service yard area Table 9 below details the predicted noise levels as a result of the service yard deliveries in isolation, a +3 db correction has been applied to the HGV movements to correct for intermittency and a + 6 db correction has been applied to the service yard operations to account for impulsivity (banging crashing etc.), assuming that impulsivity will be clearly perceptible. Noise from use of the car park has not been included in the BS 4142 assessment as these sources are not included within the scope of the BS 4142 assessment. Table 9 Rating levels generated during HGV delivery to service yard ASSESSMENT LOCATION HEIGHT PREDICTED RATING LEVEL (L Ar,1r, db) NOISE LEVEL LIMIT (L Ar,1r, db)

18 13 ASSESSMENT LOCATION HEIGHT PREDICTED RATING LEVEL (L Ar,1r, db) NOISE LEVEL LIMIT (L Ar,1r, db) It can be seen from Table 9 above that during a delivery to the supermarket service yard area, the rating level limits are predicted to be achieved by a margin of at least 6 db(a). The contribution from fixed plant items which cannot be assessed at this stage must therefore not exceed 47 db L ArTr at any assessment location in order to ensure that the cumulative contribution (deliveries and service yard together with fixed plant) does not exceed that daytime limit of 48 db L ArTr from Table For the vast majority of the time, fuel tanker deliveries will not be present and noise levels from fuel tanker deliveries have not been included in the assessment of impact during a typical hour. A separate assessment of the noise levels generated by a fuel tanker delivery has therefore been undertaken and is detailed in the following section. 8.3 NOISE FROM FUEL DELIVERIES The noise model described in Section 7.1 has been used to calculate the noise levels from fuel deliveries to the development including noise from a fuel tanker pumping and one tanker movement to and from the site using the HGV passby and fuel tanker pumping noise levels stated in Table 5. Noise levels generated by service yard deliveries and use of car parking has not been included in the modelling exercise for the fuel deliveries, as it is unlikely that service yard and fuel deliveries would happen simultaneously and as the noise sources associated with car parking are outside the scope of a BS 4142 assessment Table 10 below details the rating levels generated by the fuel tanker deliveries. The rating levels include a +3 db correction for the intermittency of the source and a +4 db correction has been applied to the fuel tanker pumping operations assuming a clearly perceptible tonal element. The assumed fuel tanker pumping location and the route of the tanker through the site are labelled in Appendix E. The pumping is anticipated to last for approximately 30 minutes per delivery. Table 10 Fuel tanker delivery noise levels ASSESSMENT LOCATION HEIGHT PREDICTED RATING LEVEL (L AR1R, db) NOISE LEVEL LIMIT (L Ar1r, db) A B C

19 14 ASSESSMENT LOCATION HEIGHT PREDICTED RATING LEVEL (L AR1R, db) NOISE LEVEL LIMIT (L Ar1r, db) D From Table 10 above it can be seen that the criterion agreed with Powys County Council has the potential to be exceeded at assessment locations B D during fuel deliveries by a margin of up to 6 db(a). This exceedance also corresponds to 6 db(a) above the prevailing background noise level on the site It should be noted that BS 4142 states the following with regard to rating levels around +5 db above background (the closest criterion to 6 db above background from the standard): A difference of around +5 db is likely to be an indication of an adverse impact, depending on the context The context in this instance is an area with high ambient noise levels. From Appendices B and D it can be seen that Measurement Location 1 is at the approximate location of Assessment Location B, and Measurement Location 2 is at the approximate location of Assessment Location D and that the noise levels measured during the baseline noise survey at these locations during the quietest points during the daytime period ranged between 54 and 62 db(a), as detailed in Table 4. Adopting the lower 54 db(a), the noise levels generated by the fuel deliveries, corrected for acoustic features would be equal to the ambient noise levels currently experienced at the receptors adjacent to measurement locations 1 and 2 and assessment locations B and D Removing the corrections for acoustic features the measurable change in noise levels at the closest noise sensitive properties would be less than 3 db(a) during a fuel delivery, as the noise levels generated by the delivery would be lower than the existing ambient noise levels. This will happen for approximately 30-minutes per week during daytime hours only It is considered therefore, given the context of high ambient noise levels and a source which would rarely be in operation, that a minor impact would result in reality. Consideration of generic mitigation measures is therefore not considered necessary. 9 CONCLUSIONS has been appointed by The Mid-Counties Co-Operative to undertake a noise impact assessment for a proposed supermarket and petrol station development in Knighton, Powys. The site is currently occupied by an existing supermarket, petrol station and associated multi-storey car park, all of which are still in use. It is intended that the existing buildings be demolished and that a new development be built in its place. A proposed scheme layout is included in Appendix B A noise impact assessment has been undertaken with reference to applicable guidance and standards. This noise assessment has been undertaken with reference to British Standard 4142:2014: Methods for rating and assessing industrial and commercial sound, British Standard 8233:2014: Guidance on Sound Insulation and Noise Reduction for Buildings, and the requirements of Powys County Council s Environmental Health Department.

20 An assessment of typical operational noise levels has been undertaken for forecourt/car park activities and supermarket deliveries (including associated HGV movements). A series of detailed noise level predictions have been undertaken with the results assessed through comparison against noise level criteria selected in accordance with the guidance contained within BS It has been identified that appropriate noise level criteria will be achieved within the closest existing residential internal habitable spaces with windows open for ventilation A BS 4142 assessment has been undertaken for a typical hour. The results of this assessment indicate that noise rating levels will be below the prevailing background noise levels on the site and that the criteria agreed with Powys County Council will be achieved A separate assessment has been undertaken for fuel deliveries as these deliveries will not happen as frequently as other deliveries to the site and will not form part of a typical hourly period. It has been identified that the addition of these fuelling activities would give rise to an exceedance of the adopted criteria. However, the receptors in the surrounding area are currently subject to noise levels at the same level as the predicted rating levels generated by the fuel deliveries, therefore a negligible noise level change would be anticipated. Hence, when context is considered, as recommended in BS4142:2014, it is suggested that impacts during fuel deliveries will be minor Noise level limits from fixed plant items associated with the building have been specified based on the results of the baseline noise survey and specifically based on the measured background noise levels at Measurement Location 3. The recommended limits give consideration to the cumulative contribution from industrial/commercial noise sources and are considered achievable provided plant and equipment are selected and located appropriately. It is therefore concluded no further mitigation measures are required, and that noise need not be considered a determining factor in granting planning permission for the proposed development.

21 Appendix A GLOSSARY OF ACOUSTIC TERMINOLOGY 16

22 Acoustic Terminology db (decibel) db(a) L Aeq,T L Amax L 10 and L 90 Free-field Level Façade Level The scale on which sound pressure level is expressed. Sound pressure level is defined as 20 times the logarithm of the ratio between the rootmean-square pressure of the sound field and a reference pressure (2x10-5 Pa). A-weighted decibel. This is a measure of the overall level of sound across the audible spectrum with a frequency weighting (i.e. A - weighting) to compensate for the varying sensitivity of the human ear to sound at different frequencies. L Aeq is defined as the notional steady sound level which, over a stated period of time (T), would contain the same amount of acoustical energy as the A - weighted fluctuating sound measured over that period. L Amax is the maximum A - weighted sound pressure level recorded over the period stated. L Amax is sometimes used in assessing environmental noise where occasional loud noises occur, which may have little effect on the overall L eq noise level but will still affect the noise environment. Unless described otherwise, it is measured using the 'fast' sound level meter response. If a non-steady noise is to be described it is necessary to know both its level and the degree of fluctuation. The L n indices are used for this purpose, and the term refers to the level exceeded for n% of the time. Hence L 10 is the level exceeded for 10% of the time, and the L 90 is the level exceeded for 90% of the time. A sound field determined at a point away from reflective surfaces other than the ground with no significant contributions due to sound from other reflective surfaces. Generally as measured outside and away from buildings. A sound field determined at a distance of 1m in front of a large sound reflecting object such as a building façade. 17

23 Appendix B REDLINE SITE BOUNDARY AND MEASUREMENT LOCATION 19

24 Measurement Location 1 Measurement Location 2 Measurement Location 3

25 Appendix C PROPOSED SCHEME LAYOUT

26 Service yard area Proposed supermarket building Proposed petrol station

27 Appendix D ASSESSMENT LOCATIONS

28 Assessment Location A Assessment Location B Assessment Location D Assessment Location C

29 Appendix E ASSUMED LOCATION OF FUEL DELIVERY NOISE SOURCES

30 Fuel tanker pumping location HGV route