CHAPTER 8 NOISE NORTHAMPTON GATEWAY

Transcription

1 CHAPTER 8 NOISE NORTHAMPTON GATEWAY

2 8 NOISE & VIBRATION 8.1 INTRODUCTION This chapter considers the potential noise and vibration effects that may arise as a result of the construction and operation of the proposed Northampton Gateway Strategic Rail Freight Interchange (SRFI) and proposed Roade Bypass. The proposed development has the potential to generate noise from the following sources: Construction of the strategic rail freight interchange (including warehousing), associated highway improvements and the Roade Bypass; The change in road traffic flows on the surrounding road network to the SRFI and around the village of Roade as a consequence of the Roade Bypass; The SRFI traffic travelling on the roads within the site boundary; The additional freight trains travelling on the Northampton Loop rail line; Freight train activity such as manoeuvring and loading/unloading taking place within the site boundary; Heavy goods vehicles (HGVs) and other operational activity such as manoeuvring and loading and unloading at the proposed warehouses and rail freight terminal; Mechanical services plant associated with the warehousing at the SRFI. There is also potential that additional rail freight activity on the Northampton Loop associated with the SFRI may lead to an increase in perceptible vibration at receptors in proximity to the railway line. At the time of writing, the baseline noise and vibration surveys are in the process of being undertaken and information about likely rail and traffic movements is not yet available at this early stage. As a result, it has not yet been possible to undertake an assessment of the noise and vibration impacts likely to result from the scheme. However, this chapter sets out the methodology, date sources and some potential issues regarding the assessment. To assist with the understanding of this chapter a Glossary of Acoustic Terms is provided in Appendix RELEVANT POLICY The overarching government policy on noise is set out in the Noise Policy Statement for England (2010). For nationally significant road, rail and strategic rail freight infrastructure projects (as defined in the Planning Act 2008), the National Networks National Policy Statement (NNNPS) sets out the relevant policy objectives. Furthermore, it identifies that in decision making, due regard must also be given to 1

3 the NPSE, the National Planning Policy Framework and the Government s associated planning guidance on noise National Policy Statement for National Networks (NNNPS), In terms of human receptors, the document specifies that noise and vibration should be assessed using the principles of the relevant British Standards and other guidance. The prediction of road traffic noise should be based on the method described in Calculation of Road Traffic Noise and prediction of noise from railways should be based on the method described in Calculation of Railway Noise. For the prediction, assessment and management of construction noise, reference should be made to any relevant British Standards and other guidance which also give examples of mitigation strategies. With respect to wildlife and biodiversity, impacts should be assessed in accordance with Biodiversity and Geological Conservation section of the NNNPS. It states that the applicant should consult Natural England with regard to assessment of noise on designated nature conservation sites, protected landscapes, protected species or other wildlife. The NNNPS notes that the results of any noise surveys and predictions may inform the ecological assessment. The NNNPS indicates that applicants should consider opportunities to address the noise issues associated with the Important Areas as identified through the noise action planning process. Regarding mitigation, the NNNPS advocates that measures should be proportionate and reasonable. It also outlines that for most projects, the relevant Noise Insulation Regulations will apply and an indication of likely eligibility for such compensation should be included in the assessment. In paragraph the document advocates that development consent should not be granted unless the development proposals will meet the following aims within the context of Government policy on sustainable development: avoid significant adverse impacts on health and quality of life from noise as a result of the new development; mitigate and minimise other adverse impacts on health and quality of life from noise from the new development; and contribute to improvements to health and quality of life through the effective management and control of noise, where possible. These statements reflect the aims of the Noise Policy Statement for England Noise Policy Statement for England (NPSE) 2 1 National Policy Statement for National Networks, Department for Transport, December Defra (2010) Noise Policy Statement for England 2

4 The NPSE is the overarching Government policy on noise. It seeks to clarify the underlying principles and aims in past and existing policy documents, legislation and guidance in relation to all forms of noise including environmental noise, neighbour noise and neighbourhood noise (but not noise in the workplace). It uses the concepts of the No Observed Effect Level (NOEL) and Lowest Observed Adverse Effect Level (LOAEL). The NPSE extends these concepts by introducing Significant Observed Adverse Effect Level (SOAEL). This is the level above which significant adverse effects on health and quality of life occur. However, the explanatory note to the NPSE states that it is not possible to identify a single objective noise value that defines SOAEL that is applicable to all sources of noise in all situations. It is likely to be different for different noise sources, for different receptors and at different times The NPSE s vision is to promote good health and a good quality of life through the effective management of noise within the context of Government policy on sustainable development. This long-term vision is supported by the following aims: Avoid significant adverse impacts on health and quality of life; Mitigate and minimise adverse impacts on health and quality of life; and Where possible, contribute to the improvement of health and quality of life The second aim of NPSE refers to noise impacts that lay somewhere between LOAEL and SOAEL. The NPSE asserts that while this means that all reasonable steps should be taken to mitigate and minimise adverse effects, this does not mean that such adverse effects cannot occur 3. National Planning Policy Framework (NPPF), The NPPF sets out the Government s planning policy for England. At its heart is an intention to promote more sustainable development. The NPPF addresses noise as a planning issue principally through a statement of four principles at paragraph 123: Planning policies and decisions should aim to: Avoid noise from giving rise to significant adverse impacts on health and quality of life as a result of new development; Mitigate and reduce to a minimum other adverse impacts on health and quality of life arising from noise from new development, including through the use of conditions; Recognise that development will often create some noise and existing businesses wanting to develop in continuance of their business should not have unreasonable restrictions put on them because of changes in nearby land uses since they were established, and Identify and protect areas of tranquillity which have remained relatively undisturbed by noise and are prized for their recreational and amenity value for this reason. 3 Defra (2010) Noise Policy Statement for England, page 9, paragraph Department for Communities and Local Government (DCLG), (2012), National Planning Policy Framework 3

5 It can be seen how the NPPF reflects the aims of the NPSE. Furthermore, the NPPF makes reference to the NPSE for advice on the achievement of these policy aims, and particularly for the explanation of adverse impacts. Planning Practice Guidance (Noise) (PPG(N)) Further guidance in relation to the NPPF has been published on the Government Planning Portal. The Planning Practice Guidance: Noise supports the NPPF by providing a range of advice and includes a noise exposure hierarchy based on the likely average response In line with the NPPF and NPSE, the guidance confirms that significant adverse effects should be avoided. At the next level down the hierarchy, where there is an observed adverse effect, the PPG(N) confirms that effects should be mitigated and reduced to a minimum as far as reasonably practicable. No mitigation measures are required for effects which are considered to be below the lowest observed adverse effect level. Local Policy The local planning policy context will be addressed in detail in the separate Planning Statement which will form part of the submitted application. The West Northamptonshire Joint Core Strategy Local Plan (Part 1) 2014 contains two policies that are considered relevant to the assessment of noise impacts arising from the proposed development Policy S10 Sustainable Development Principles, indicates that development will minimise pollution from noise air and run off Policy BN9 Planning for Pollution Control, indicates that proposals which are likely to cause pollution or result in exposure to pollution will need to demonstrate that they provide opportunities to minimise, and where possible, reduce pollution issues that are a barrier to including sustainable development and healthy communities, including reducing the adverse impacts of noise. This policy also states that Development which is likely to cause pollution, either individually or cumulatively, will only be permitted if measures can be implemented to minimise pollution to a level which provides a high standard of protection for health and environmental quality It can be seen that the specific local policies are consistent with national policy objectives and therefore achieving the national policy objectives will also satisfy the local policy requirements In addition, the assessment will take into consideration a number of British Standards and other guidance documents. These are likely to include: Calculation of Road Traffic Noise (CRTN), 1988; Calculation of Railway Noise (CRN), 1995; 5 Planning Practice Guidance: Noise - 4

6 Noise Insulation Regulations, 1975 (as amended 1988); The Noise Insulation (Railways and Other Guided Transport Systems) Regulations, 1996; Design Manual for Roads and Bridges Part 7 HD213/11 Noise and Vibration (DMRB), November 2011; BS 4142:2014 Method for rating and assessing industrial and commercial sound; BS 5228:2009+A1:2014 (Parts 1 and 2) Code of Practice for Noise and Vibration Control Construction and Open Sites; BS 8233:2014 Guidance on sound insulation and noise reduction for buildings; BS :2008 Guide to evaluation of human exposure to vibration in buildings. Vibration sources other than blasting; ISO :1996 Acoustics Attenuation of sound during propagation outdoors part 2: General method of propagation; World Health Organisation, Guidelines for Community Noise (1999); IEMA Guidelines for Environmental Noise Impact Assessment (2014). Consultation At the time of writing, a formal Environmental Statement Scoping Opinion has not been received for the proposed development Prior to commencing the baseline noise and vibration surveys, monitoring positions were discussed with the relevant officials at South Northamptonshire District Council and Northampton District Council It is not anticipated that there would be any significant vibration effects arising from HGVs accessing the SFRI via the A508 or travelling along the access roads within the development, due to the distance to the sensitive receptors and the roads being newly surfaced/smooth. Furthermore, for the same reasons, it is not anticipated there would be any significant vibration effects associated with the Roade Bypass. Therefore, it is not proposed to undertake an assessment of operational vibration from these sources. An assessment will be undertaken of the likely operational vibration associated with the increase in freight train movements along the Northampton Loop rail line. Cumulative Effects To provide an assessment of the cumulative effects, the impacts of noise and vibration from other committed or potential developments that might affect the same sensitive receivers will be considered in addition to the likely impacts of the proposed development. 5

7 8.3 ASSESSMENT METHODOLOGY & SIGNIFICANCE CRITERIA Assessment Methodology The proposed development has the potential for several different types of impacts. Broadly speaking these comprise: Construction noise; Construction vibration (depending on the construction techniques to be used) Operational noise resulting from additional freight train movements; Operational vibration arising from additional freight train movements; Operational noise resulting from changes in road traffic associated with the scheme and the proposed bypass; Operational noise arising from the loading/unloading and manoeuvring of HGVs and freight trains at the SRFI and any mechanical services plant noise emission associated with the SRFI For each element of the assessment different methodologies apply for the prediction and assessment of the likely noise and vibration impacts and the determination of any likely significant effects. The significance of an effect is dependent upon several factors, including the noise level from the particular activity, the existing sound environment and the duration, timing and character of the various sources. The assessment methodologies that will be used for each assessment are discussed below Construction Noise An indication of the potential effect of construction works associated with the proposed development will be determined at the nearest noise sensitive receivers based on predicted noise levels from preliminary estimates of construction plant and machinery that are likely to be used. The noise predictions will follow the principles of the methodology contained within Annex F of BS :2009+A1:2014. This standard has been formally adopted by Government as a Code of Practice to use in this situation. The impact of construction traffic on noise sensitive receivers will also be considered. This is will be determined following the principles of the Calculation of Road Traffic Noise (1988) and the Design Manual for Roads and Bridges Construction Vibration At this stage, it is not yet clear whether the construction will involve operations likely to generate material levels of vibration at sensitive receptors. If such methods are to be used, the principles of BS :2009+A1:2014 would be used to determine the extent of any effects. 6

8 Operational Phase Rail Noise Rail traffic using the network will change due to the operational phase of the project. The effects resulting from the change in rail noise will be predicted using IMMI 3D noise modelling software and the methodology contained within the Calculation of Railway Noise (CRN). Operational Phase - Road Traffic Noise The effects resulting from the change in road traffic noise due to the operation of the development will be predicted using IMMI 3D noise modelling software and the methodology contained within the Calculation of Road Traffic Noise (CRTN). For the road traffic noise assessment, noise levels will be predicted for the following scenarios: 2016 Baseline; 2021 Baseline (opening year); 2031 Baseline (future assessment); 2021 with development (opening year); 2031 with development (future year). Operational Phase Strategic Rail Freight Interchange Operations Noise from operational activities at the SRFI has the potential to impact surrounding receptors during both the day and night time periods. This will include HGVs manoeuvring and loading/unloading, the operation of forklift trucks, crane movements and other manoeuvring and loading/unloading sources associated with the trains The anticipated operational noise levels from the SRFI will be predicted based upon the methodology in ISO : The methodology contained in BS 4142:2014 will be adopted to determine and assess the potential impacts from the SRFI. The method focuses on the difference between sound from the source being assessed (the specific sound level) and the existing background sound level The standard also indicates that certain characteristics can increase the extent of the impact over that expected from a simple difference in noise levels, including tonality, impulsivity and intermittency. The standard describes various options for taking any such features into account and for determining what is described as a rating level The standard states that the extent of the impact can be determined by subtracting the representative background sound level from the rating level. The greater the difference the greater the magnitude of the impact. The standard states that: 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; 7

9 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; and 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 The standard indicates that while the difference between the rating level and background sound level provides an initial estimate of the impact, the absolute noise levels should also be considered, as should the character and level of the particular noise source with the existing sound environment Regarding consideration of the absolute noise levels, the relevant guideline values provided in BS 8233:2014 will be used. Table 4 of that standard sets out desirable internal levels to be achieved in new dwellings from external sources. Information is also provided regarding desirable noise levels for external amenity spaces associated with dwellings. The various values from BS 8233:2014 are summarised in Table 8.1. Table 8.1 Summary of guideline values from BS 8233:2014 Recommended Level/Situation Inside Bedrooms and Living Rooms Time Period Day (07:00 23:00) Desirable Noise Level not to be exceeded (db) db LAeq,T Inside Bedrooms Night (23:00 07:00) db LAeq,T Inside Dining Room/area Day (07:00 23:00) db LAeq,T Outside Amenity Space Day (07:00 23:00) db LAeq,T It should be noted that the lower values shown in the table above are generally regarded as the LOAEL for steady external noise, i.e. no adverse effect due to noise would be expected If the noise has character, it might be appropriate to consider a lower value as LOAEL The World Health Organisation s Guidelines for Community Noise (1999) will be used to consider the potential impact from any maximum short term noise levels arising from operational activities at the SRFI site at night. The guidelines indicate that, for a good sleep, indoor sound pressure levels should not exceed approximately 45 db L Amax more than times per night. This equates to a level at the outside façade of 60 db L Amax assuming the noise reduction with a window partially open is 15 db. It is generally accepted that this criterion is a LOAEL The Institute of Environmental Management and Assessment (IEMA) published their Guidelines for Environmental Noise Impact Assessment in The document describes the recommended process for undertaking such assessments. It notes 8

10 that the extent of the effects of noise impact can rarely be determined solely by the difference between current and future noise levels, and that there are other factors to consider when determining the effect. These principles will be followed in this assessment. Operational Vibration The proposed development has the potential to generate vibration from additional freight train movements on the rail network. The assessment of vibration from the operational phase of the development will be undertaken following the principles of BS :2008. This standard describes the determination of the vibration dose that is experienced over a period of time from measurements or predictions of vibration levels. The standard identifies the probability of adverse comment from the vibration dose value (VDV) as summarised in Table 8.2. Table 8.2 Vibration dose value ranges which result in various probabilities of adverse comment. Place and Time Residential buildings 16 hour day Residential buildings 8 hour night Low probability of adverse comment (mm ) Adverse comment possible (mm ) Adverse comment probable (mm ) 0.2 to to to to to to BASELINE CONDITIONS Noise To determine and quantify the existing baseline sound environment, surveys commenced in September 2016 and are currently ongoing. Monitoring is being undertaken at several locations selected to be representative of the existing noise sensitive receivers near the proposed SRFI and Roade Bypass. The aim of the surveys is to quantify the existing baseline conditions against which the impacts of the proposed development can be assessed. The completed noise surveys will comprise unattended measurements at 15 locations described in Table 8.3 and attended sample measurements at 12 locations described in Table 8.4. All locations are illustrated in Appendix

11 Table 8.3 Unattended monitoring locations L1 L2 L4 L5 Location Collingtree Road High Street, Collingtree 15 Barn Lane, Milton Malsor West Lodge Farm Observations Dominated by distant road traffic noise from the M1 and from passing vehicles travelling along Collingtree Road. Intermittent train passbys audible. Dominated by high levels of road traffic noise from the M1. Distant road traffic noise from M1, noise from intermittent train passbys Distant traffic noise from M1 at low level, intermittent train movements, trees resulting in the wind. L6 Lodge Farm (TBC) To be confirmed. L7 Collingtree Road Dominated by distant road traffic noise from the M1 and from passing vehicles travelling along Collingtree Road. Intermittent train passes audible. L8 Hilton Hotel Dominated by road traffic noise from the M1 and contributions from vehicles using the car park. L9 Holiday Inn Express Dominated by road traffic noise from M1 and A45. Local vehicle noise from cars parking. L10 West Lodge Farm Dominated by road traffic noise from A508 Cottages Northampton Road. L11 Windingbrook Lane, Dominated by road traffic noise from A45 and M1. Collingtree L12 Adjacent to Woodleys Farmhouse Day Dominated by road traffic noise on Northampton Road A508. Nursery L13 Adjacent to Bailey Dominated by road traffic noise from the east and L14 L15 L16 Brooks Lane, Roade Blisworth Road, Roade near to Hyde Farm Rear of Dovecote Road, Roade Dovecote Farm/Hyde Farm House, Roade intermittent train pass bys. Constant distant road traffic noise from the east, intermittent train pass bys and traffic along Blisworth Road Constant road traffic noise to north east occasional train pass bys. Low level road traffic noise to the north (M1) 10

12 Table 8.4 Attended Sample Monitoring Locations Location Observations S3 Hilton Hotel (East Side) Dominated by road traffic noise from A45 S4 Rathvilly (TBC) Not yet undertaken. S5 Stockwell Road Dominated by road traffic noise from the M1 and passenger and freight train passes. High altitude aircraft noise observed. S6 Saxon Avenue Dominated by road traffic noise from the A45 and local movements on Saxon Avenue. S7 Courteenhall Dominated by road traffic noise from the M1 S8 Roade, near junction of London Road A508 and Northampton Road Dominated by road traffic noise from A508. S9 Stratford Road A508 Dominated by road traffic noise from A508 S10 Off Blisworth Road Not yet undertaken. S11 NML3 NML 4 Stratford Road near Netherwood Bridge Cottage, Courtenhall Road Courtenhall Road (near to Blisworth Lodge Farm) Dominated by road traffic noise from Stratford Road. High altitude aircraft noise observed. Frequent road traffic noise from Courteenhall Road and train passes (at least 6 per 15 minute period). High altitude aircraft noise observed. Road traffic noise from Couteenhall Road and train passes. NML 5 Northampton Road Not yet undertaken A weather station has also been installed near position L5 to log the precipitation, wind speed and wind direction during the survey. The noise data will be analysed alongside the prevailing weather conditions to exclude periods where data is like to have been contaminated by high wind speeds and precipitation. Once analysed, typical baseline noise levels will be derived which will be used to assess the potential operational noise impacts. The NNNPS identifies that applicants should consider opportunities to address the noise issues associated with the Important Areas as identified through the noise action planning process. The following important areas are near the development scheme: A section of the A508 through Roade (road traffic); properties adjacent to the existing railway track in Roade (railway noise); High Street, Collingtree at the properties adjacent to the M1 (road traffic). 11

13 Vibration The change in vibration at the nearest sensitive receptors resulting from additional freight trains will consider the existing baseline vibration levels that occur at these properties. Measurements of the existing vibration level at a position representative of the nearest receptor will be undertaken in the area surrounding positions V1 and V2 as shown in Appendix Anticipated Likely Impacts and Effects We have not yet been able to undertake an assessment of the noise impacts likely to result from the scheme. However, based on our work to date and our experience of assessing similar sites, we have provided an outline of what we anticipate the likely impacts could be. For properties to the east of the M1, the anticipated levels of sound from operational activities at the SRFI would be such that little to no adverse impact is expected to occur. This is due to the mitigation provided by the landscaping and the generally higher ambient noise levels that exist as the receptors are close to the M1. It is expected that the development would result in at most a negligible or minor adverse impact at these properties. Properties to the west of the M1 are more likely to experience some operational noise from the SRFI due to their relatively close proximity to the site boundary and generally lower ambient noise levels. The scheme design does include inherent mitigation provided by the landscaping which will help to minimise any adverse impacts. There is also likely to be increased railway noise at receptors near to the Northampton Loop railway line due to the additional freight train movements. The extent of this impact will be investigated and determined in the subsequent assessment work. At the detailed design stage, depending on the precise layout and operation of the warehouses, HGVs will as far as possible be encouraged to have white noise reversing alarms which is increasingly common on newer vehicles. Furthermore, if refrigerated HGVs are likely to use the site, electric docking stations will be used to minimise the need for HGVs to keep their chiller units operating and engines idling when at the SRFI. There will be an increase in traffic on the local road network associated with vehicles travelling to and from the proposed SRFI site. When added to the existing baseline flows on these roads, these vehicles are anticipated to result in a relatively modest increase in road traffic noise which is unlikely to be particularly noticeable at most nearby receptors and therefore will generally result in at most a negligible or minor adverse impact. However, this will be confirmed or otherwise once the transport and acoustic modelling has been completed. The proposed Roade bypass is anticipated to reduce the volume of traffic on the A508 through the centre of Roade, noticeably reducing the traffic noise and having a 12

14 8.5.7 beneficial impact at receptors close to that part of the A508. Creation of the bypass is likely to increase the traffic noise experienced on the outskirts of Roade near the bypass. The assessment work to be undertaken in due course will consider what mitigation might reasonably be required to minimise any adverse impacts at these receivers. There is also potential for an increase in perceived vibration at the nearest dwellings to the existing railway in Milton Malsor, though the extent of this impact cannot be determined until modelling and prediction work has been completed. 8.6 FURTHER WORK The following tasks are being undertaken in relation to the noise and vibration assessment: Completion of baseline noise monitoring at all locations for sufficient period to capture a representative sample; Completion of baseline vibration monitoring; Identification of the relevant noise sensitive receiver locations for each assessment; Review of any scoping and consultation responses and any actions that may subsequently arise; Preparation of acoustic model for the SRFI and the proposed Roade Bypass; Construction noise predictions and assessment; Prediction and assessment of road traffic and railway noise impacts associated with the proposed development; Operational noise and vibration predictions and assessment for the SRFI; Assessment of the significance of the likely noise and vibration impacts; Investigation of any mitigation measures which may be required and what benefit would result from such measures; Determination of residual effects; Proposals for noise and vibration monitoring during the construction and operational phases. 13

15 Appendix 8.1 Glossary of Acoustic Terms Noise is defined as unwanted sound. The perception of sound arises from small pressure fluctuations at the eardrum leading to the sense of hearing. Human ears can respond to sound in the frequency range of approximately 20 Hertz (Hz) (low pitch) to 20,000 Hz (high pitch). Whilst the level of sound could be described in terms of different pressures, the range of sensitivity of the human ear is very large and it is easier to use the unit of decibel (db) to quantify sounds. The human ear can detect sounds in the approximate range of 0 db (the threshold of perception) to 140 db (commonly described as the threshold of pain). The ear does not respond equally to sounds of the same magnitude at different frequencies, but, instead, it is more responsive to mid frequencies than to lower or higher frequencies. To quantify noise in a manner that approximates the response of the human ear, an electronic weighting mechanism is used when sound is measured. This weighting reduces the importance of lower and higher frequencies, in a similar manner to the human ear. The most commonly used weighting mechanism that best corresponds to the response of the human ear is the A -weighting scale. This is widely used for environmental noise measurement and assessment, and the levels are denoted as db(a). Whether sound is perceived as noise depends on a number of factors, which should be considered in any assessment. Generally, the extent of the impact and effect of noise depends upon: - its level, - the margin by which the particular source of noise exceeds the prevailing baseline level, - the character of the source in relation to the character of the baseline noise environment - how the sound varies over a given period of time; - when the sound occurs, i.e. during the day, evening or night; or at weekdays or weekends - the acoustic features of the source (such as its general frequency content, whether it has tonal qualities or whether the source is impulsive in nature). The decibel scale is logarithmic. This means that if two sources of the same sound pressure level are combined, this doubling of the sound energy gives a resultant level 3 db higher than the decibel value of the single source. Subjectively, experiments have shown that in general a 10 db increase is regarded as a doubling of perceived loudness, and a change in sound level of 3 db is generally the minimum difference that can be perceived under normal listening conditions. Sound levels are rarely constant, and a range of indicators are used to describe the varying sounds that occur. A description of the main indicators is given below, along with some other technical terms that tend to be used in noise impact assessments. L Aeq,T : The equivalent continuous A-weighted sound or noise level over the time period (T). This is the A-weighted sound pressure level of a continuous, steady sound that, over the given time period (T), contains the same sound energy as the actual fluctuating sound over the same time period. L A90,T : This is the A weighted noise level exceeded for 90% of the measurement period, T. This is often described the background sound or noise level. L A10,T : This is the A weighted noise level exceeded for just 10 % of the measurement period, T. L A10,18h : This is the arithmetic average of the hourly (L A10,1h ) values for each of the eighteen one-hour periods between 06:00 and 24:00 hours. This indicator is normally used to describe road traffic noise. L Amax,T : This is the maximum 'A' weighted noise level that occurs during the measurement period, T. It is used to show the highest noise level that occurred in that time period. In some situations the effect of noise is more associated with the maximum value than, for example, the L Aeq,T indicator.

16 Façade Level: The sound level at a position 1 m in front of a reflecting façade of a building. The façade noise level is assumed to be 3 db(a) higher than the level measured or predicted at an the same position but without the influence of the reflecting facade Free-field Level: The sound level in an open area well away from any buildings or other sound reflecting surfaces other than the ground. Generally, the minimum distance from building facades required for free-field measurements is 3.5 m. BS4142:2014 Terminology - Background Sound Level: The A-weighted sound pressure level that is exceeded by the residual sound at the assessment location for 90% of a given time interval. Expressed as L A90,T and generally considered to be the average minimum noise level. - Ambient Sound Level: Totally encompassing sound in a given situation at any given time, usually composed of sound from many sources near and far. Usually expressed in terms of L Aeq,T and includes the residual and specific sound when present. - Residual Noise Level: The ambient noise remaining at the assessment location when the specific noise source is suppressed to such a degree that it does not contribute to the ambient noise. Expressed in terms of L Aeq,T - Specific Sound Level: The equivalent continuous A-weighted sound pressure level produced by the specific sound source (being assessed) at the assessment position over a given reference time interval (L Aeq,Tr ) - Rating Noise Level: The specific sound level plus any adjustment for the characteristic features of the sound. Expressed in terms of L Ar,Tr. Noise Policy Statement for England Terminology - No Observed Effect Level (NOEL): This is the level below which no effect can be detected. In simple terms, below this level, the sound has no effect at all (e.g. it is inaudible). - Lowest Observed Adverse Effect Level (LOAEL): This is the level above which adverse effects on health and quality of life can be detected. - Significant Observed Adverse Effect Level (SOAEL): This is the level above which significant adverse effects on health and quality of life occur. Vibration Dose Value this is a measure of the amount of vibration that is experienced over a specified period (normally the 16-hour day ( hours) or 8-hour night ( hours). It is used to determine the likelihood of adverse comment about vibration. Mathematically it is defined as the integral over time of the fourth power of the frequency-weighted, time varying vibration acceleration magnitude multiplied by the duration, all to the fourth root. Its units are mm

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