This report assesses the outward noise and vibration impact of the proposed development on its surrounding environment.

Transcription

1 8. NOISE AND VIBRATION 8.1 Introduction This report has been prepared by AWN to form part of an EIAR for the proposed residential development at Wonderful Barn, Barnhall, Leixlip. The chapter assesses the likely noise and vibration impact of the development in the context of current relevant standards and guidance, and identifies any requirements or possibilities for mitigation. This report assesses the outward noise and vibration impact of the proposed development on its surrounding environment. The development will involve the construction of 450 residential units, a childcare facility, vehicular entrance to the site and car parking. 8.2 Study Methodology The assessment has been undertaken with reference to the most appropriate guidance documents relating to environmental noise and vibration which are set out within the relevant sections of this chapter. In addition to specific noise guidance documents, the following guidelines were considered and reviewed for the preparation of this chapter: Guidelines on the Information to be contained in Environmental Impact Statements, (EPA, 2002); EPA Advice Notes on Current Practice (in the preparation of Environmental Impact Statements), (EPA, 2003); Guidelines on the Information to be contained in s, (Draft August 2017); and EPA Advice Notes for Preparing Environmental Impact Statements, (Draft, September 2015). The study has been undertaken using the following methodology: Baseline noise monitoring has been undertaken in the vicinity of the development site in order to characterise the existing noise environment; A review of the most applicable standards and guidelines has been conducted in order to set a range of acceptable noise and vibration criteria for the construction and operational phases of the proposed development; Predictive calculations have been performed during the construction phase of the project at the nearest sensitive locations to the development site; Predictive calculations have been performed to assess the potential impacts associated with the operational of the development at the most sensitive locations surrounding the development site, and; 8-1

2 A schedule of mitigation measures has been proposed to reduce, where necessary, the identified potential outward impacts relating to noise and vibration from the proposed development. 8.3 Receiving Environment The site under consideration is located to the south west of Leixlip town, at Barnhall, Co. Kildare. The site is bound to the north by a number of residential estates, to the south by gardens of the Wonderful Barn complex and the M4 Motorway beyond, to the east by residential developments and the R404 Road beyond and to the west by residential developments and R449 beyond Environmental Noise Survey An environmental noise survey has been conducted at the site in order to quantify the existing noise environment. The survey was conducted in general accordance with ISO 1996: 2007: Acoustics Description, measurement and assessment of environmental noise. Specific details are set out below. Survey Periods and Instrumentation An attended noise survey was conducted at the site over a daytime period to obtain a profile of typical noise levels at different locations in close proximity to and away from the M4 Motorway to determine noise levels across the development site. The survey was conducted between 10:30 and 13:30hrs on 25 November 2016 using a Brüel and Kjaer Type 2250 Sound level meter. Noise levels were measured over 15 minute periods at each location. Choice of Measurement Locations Three measurement locations were selected as shown in Figure 8.1 and described below. Location N1 Location N2 Location N3 is located along the south eastern boundary of development in proximity to the residential dwellings within Elton Court and also representing the location of properties proposed within the development. is located along the south-western boundary of the development site in proximity to Rinawade Lawns and at the location of proposed properties within the development site. is located along the northern portion of the development site, north of The Wonderful Barn gardens and in proximity to residential estates to the north, west and east. 8-2

3 Figure 8.1 Baseline Noise Monitoring Locations Measurement Parameters The noise survey results are presented in terms of the following parameters. L Aeq 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. L A10 is the sound level that is exceeded for 10% of the sample period. It is typically used as a descriptor for traffic noise. L A90 is the sound level that is exceeded for 90% of the sample period. It is typically used as a descriptor for background noise. L AFmax is the instantaneous maximum sound level measured during the sample period using the F time weighting. The A suffix denotes the fact that the sound levels have been A-weighted in order to account for the nonlinear nature of human hearing. All sound levels in this report are expressed in terms of decibels (db) relative to 2x10-5 Pa. Survey Results and Discussion The results of the surveys at the three monitoring locations are summarised below. Location N1 Table 8.1 below presents a summary of noise levels measured at Location N1. 8-3

4 Table 8.1 Noise Survey Results at Location N1 Start Time Measured Noise Levels (db re. 2x10-5 Pa) L Aeq L Amax L A10 L A90 10: : : Average Noise levels measured at this location were dominated by traffic along the M4 Motorway, traffic along the R404, occasional traffic passing along local access road pedestrian activity and overhead aircraft. Location N2 Table 8.2 below presents a summary of noise levels measured over the daytime period at Location N2. Table 8.2 Noise Survey Results at Location N2 Start Time Measured Noise Levels (db re. 2x10-5 Pa) L Aeq L Amax L A10 L A90 11: : : Average Noise levels measured at this location were dominated by traffic along the M4 Motorway, overhead aircraft and occasional pedestrian activity. Location N3 Table 8.3 below presents a summary of noise levels measured over the daytime period at Location N3. Table 8.3 Noise Survey Results at Location N3 Start Time Measured Noise Levels (db re. 2x10-5 Pa) L Aeq L Amax L A10 L A90 10: : : Average Noise levels measured at this location were noted to be influenced by distance M4 traffic, birdsong and overhead aircraft. Baseline Noise Summary Noise levels recorded along the southern portion of the site were dominated by road traffic from the M4 Motorway which contributed to relatively high noise levels at monitoring locations N1 and N2. Lower noise levels were recorded at Location N3 set back from road traffic and is considered representative of noise levels to the rear of properties located along the development boundary and at the location of proposed properties within the development set back from the M4 Motorway. 8-4

5 8.4 Characteristics of the Proposal The proposed development will involve the construction of 450 houses, a crèche, a new site entrance, internal roads, landscaping and boundary treatments. When considering a development of this nature, the potential noise and vibration impacts on the surroundings must be considered for each of two distinct stages. During the construction phase the main site activities will include, site clearance, building construction, internal road construction and landscaping. This phase will be of short term impact. During the operational phase of the development, no significant sources of noise or vibration are expected with the development. The primary source of outward noise in the operational context relates to any changes in traffic flows along the local road network. 8.5 Potential Impacts of the Proposal Assessment Criteria Construction Phase Noise Kildare County Council (KCC) include the following construction noise limits within the Kildare Local Authorities Second Noise Action Plan ( ) in order to control construction noise impacts at noise sensitive buildings. Table 8.4 Construction Noise Limits set by Kildare County Council Day Working Hours Level, db L Aeq Maximum, db L Amax 07:00 to 19:00hrs Monday to Friday 19:00 to 22:00hrs Saturday 08:00 to 16:30hrs Sundays and Bank Holidays 08:00 to 16:00hrs Vibration The noise action plan does not contain guidance relating to vibration magnitudes or limit values. In this instance, best practice is taken from British Standard BS 5228 Code of Practice for Noise and Vibration Control on Construction and Open Sites - Part 2 Vibration ( A1 2014). This standard recommends that for soundly constructed residential property and similar structures that are generally in good repair, a threshold for minor or cosmetic (i.e. non-structural) damage should be taken as a peak component particle velocity (in frequency range of predominant pulse) of 15mm/s at 4Hz increasing to 20mm/s at 15Hz and 50mm/s at 40Hz and above. The standard also notes that below 12.5 mm/s PPV the risk of damage tends to zero. It is therefore common, on a cautious basis to use this lower value. The standard notes that important buildings which are difficult to repair might require special consideration on a case-by-case basis. A building of historical value should not (unless it is structurally unsound) be assumed to be more sensitive. Taking account of the protected status of the Wonderful Barn and the potential vulnerability of the structure, however, the vibration limits set for this building are reduced by 50% 8-5

6 of those used for modern buildings to ensure no cosmetic or structural damage. On a very cautious basis, the vibration magnitudes recommended for 15Hz and under have been limited for all frequency bands. Table 8.5 below summarises the proposed vibration limits during the construction phase. Table 8.5 Recommended Vibration Criteria During Construction Phase Allowable vibration (in terms of peak particle velocity) at the closest part of sensitive property to the source of vibration, at a frequency of: Building Type Less than 15Hz 15 to 40Hz 40Hz and above Light framed structures/ residential buildings Protected Building 12 mm/s 20 mm/s 50 mm/s 6mm/s Operational Phase Noise The main potential source of outward noise impact associated with the proposed development relates to additional traffic flows on the surrounding road network. Given that traffic from the development will make use of existing roads already carrying traffic volumes, it is appropriate to consider the increase in traffic noise level that arises as a result of vehicular movements associated with the development using the L A10 parameter which is typically used to describe traffic noise. In order to assist with the interpretation of the noise associated with vehicular traffic on public roads, Table 8.6 offers guidance as to the likely impact associated with any particular change in traffic noise level (Source DMRB, 2011). Table 8.6 Likely Impact Associated with Change in Traffic Noise Level Change in Sound Level (db L A10) Subjective Reaction Magnitude of Impact 0 Inaudible No Impact Barely Perceptible Negligible Perceptible Minor Up to a doubling of loudness Moderate 10+ Doubling of loudness and above Major For other non-traffic related sources appropriate guidance on internal noise levels for dwellings is contained within BS 8233: 2014: Guidance on Sound Insulation and Noise Reduction for Buildings. This British Standard sets out recommended noise limits for indoor ambient noise levels in dwellings as follows: Table 8.7 Recommended Indoor Ambient Noise Levels From BS 8233: 2014 Typical situations Daytime L Aeq,16hr (07:00 to 23:00hrs) Design Range, L Aeq,T db Night-time L Aeq, 8hr (23:00 to 07:00hrs) Living / Dining Rooms 35 / 40 n/a Bedrooms

7 Vibration There are no expected sources of vibration associated with the operational phase, therefore, vibration criteria have not been specified for this phase Construction Phase Potential Impacts Construction Noise A variety of items of plant will be in use for the purposes site clearance and construction. There will be vehicular movements to and from the site that will make use of existing roads. Due to the nature of these activities, there is potential for the generation of elevated levels of noise. It is possible to predict indicative noise levels using guidance set out in BS 5228 Part 1 (2008 +A1 2014) for the main phases of the proposed construction works. The nearest third party noise sensitive locations to the proposed construction works are the properties within residential estates which border the north, west and east of the site boundary. The closest works areas are at distances between 15 to 30m from the nearest properties with the remainder of works taking place across the site at varying distances of up to 250m. In order to assess a worst case scenario, construction noise levels at distances of 15m, 30m and 100m have been used The calculations assume that the equipment will operate for 66% of the 12-hour working day (i.e. 8 hours). No screening from site hoarding or other site features are included in the calculations. Table 8.8 summarises the construction noise prediction calculations at the nearest residences using the assumptions set out above. Table 8.8 Indicative Construction Noise Levels at Nearest Noise Sensitive Locations. Construction Phase Item of Plant (BS Ref) Construction Noise L Aeq at distance of 15m 30m 100m Site Clearance/ Demolition General Construction Road Works/ Landscaping Tracked excavator (C2.21) x 2 No Dump Truck (C2.30) Diesel Generator (C4.76) Total site clearance Dump Truck (C2.30) Tracked excavator (C2.21) x 2 No Hand Held Circular Saw (C4.72) Diesel Generator (C4.76) Total General Construction Asphalt Paver & Tipping Lorry (C5.30) Electric Water Pump (C5.40) Vibratory Roller (C5.20) Total Landscaping and Road Works The predicted noise levels detailed in the above table indicate that for the likely range of the works, construction activities can operate within the limits adopted from Kildare County Councils Noise Action Plan for the majority of periods. There is potential for the adopted criteria to be exceeded when construction works are taking place immediately along the closest works boundary (at distance of 15m) during the general housing construction works, this assumes, however that all items of equipment assessed are operating simultaneously along this boundary and no screening is provided by boundary treatments, which is very worst case. 8-7

8 It is important to note that the calculations set out above are based on assumed site activity and a combination of plant items operating simultaneously. The use of construction noise and vibration mitigation measured will be employed during the construction phase to ensure the adopted limits are not exceeded. Given the relatively short-term nature of these worst-case operations, the likely noise impact on the local environment will be short-term and slight over an intermittent period. Construction Vibration Potential for vibration impacts during the construction phase programme are likely to be limited given the minimal level of ground breaking and excavations required. For typical residential developments, standard excavation and foundation building techniques do not require the use of any significant vibration generating plant (i.e. driven piles, rock breaking equipment etc.). Vehicles used to transport building materials to and from the site will also not result in any significant vibration levels. For the purposes of this assessment, however, typical vibration levels during piling assuming augured or bored piles have been determined through reference to published empirical data. The British Standard BS 5228 Part 2: Vibration, publishes the measured magnitude of vibration of rotary bored piling using a 600mm pile diameter for bored piling into soft ground over rock, (Table D.6, Ref. No. 106): 0.54mm/s at a distance of 5m, for auguring; 0.22mm/s at a distance of 5m, for twisting in casing; 0.42mm/s at a distance of 5m, for spinning off, and; 0.43mm/s at a distance of 5m, for boring with rock auger. Considering the low vibration levels at very close distances to the piling rigs, vibration levels at the nearest buildings are not expected to pose any significance in terms of cosmetic or structural damage to either standard or protected buildings. In addition, the range of vibration levels is typically below a level which would cause any disturbance to occupants of nearby buildings. The likely vibration impacts during the construction phase are deemed to be neutral, temporary and of imperceptible significance. Notwithstanding the above, any construction activities undertaken on the site will be required to operate below the recommended vibration criteria set out in Table 8.5 during all activities Operational Phase Potential Impacts Once the development is completed, the potential noise impacts to the surrounding environment are minimal. The residential aspect of the development is not expected to generate any significant noise sources over and above those which form part of the existing environment at neighbouring residential areas (estate vehicle movements, children playing etc.) and hence no significant impact are expected from this area of the development site. The main potential noise impact associated with the proposed development is considered therefore to relate to the generation of additional traffic to and from the site as a result of the new residential element and potentially from activities associated with an outdoor crèche play area. These are assessed in the following sections. Once operational, there are no vibration sources associated with the development site. 8-8

9 Direct Impacts Additional Vehicular Traffic on Surrounding Roads A traffic impact assessment relating to the proposed development has been prepared by ILTP as part of this EIAR. Information from this report has been used to determine the predicted change in noise levels in the vicinity of a number of roads in the area surrounding the proposed development, for the opening year 2019 and the design year Figure 8.2 illustrates the traffic assessment locations at assessed as part of the traffic analysis. Figure 8.2 Traffic Assessment Locations (Source DBFL) For the purposes of assessing potential noise impact, it is appropriate to consider the relative increase in noise level associated with traffic movements on existing roads and junctions with and without the development given that traffic from the development will make use of the existing road network. Traffic flow data for the opening year of 2019 and the design year of 2034 in terms of the Annual Average Daily Traffic (AADT) has been assessed. The periods have been assessed and the calculated change in noise levels during these two years are summarised in Tables 8.9 and

10 Table 8.9 Change in Traffic Noise Levels with Proposed Development, 2019 Traffic Junction 2017 Opening Year AADT (No Dev) 2017 Opening Year AADT (With Dev) AADT % HGV AADT % HGV Change in noise Level, db A 2, , B 17, , C 6, , D 14, , E 7, , F 13, , G 14, , Table 8.10 Change in Traffic Noise Levels with Proposed Development, 2034 Traffic Junction 2017 Opening Year AADT (No Dev) 2017 Opening Year AADT (With Dev) AADT % HGV AADT % HGV Change in noise Level, db A 2, , B 20, , C 8, , D 16, , E 8, , F 15, , G 17, , The predicted increase in AADT traffic levels associated with the development is less than 1dBA in the vicinity of all roads included in the ILTP report for both the opening and design years. Reference to Table 8.6 confirms that this increase is negligible. In summary, the predicted increase in noise levels associated with vehicles at road junctions in the vicinity of the proposed development is neutral, long term and not significant. Crèche Noise Impacts Measurement of noise levels generated by children playing outdoors in a number of crèches and kindergartens indicate typical noise levels in the order of 56dB L Aeq,1hr at distance of 5 metres. The nearest existing of-site noise sensitive locations to the west are approximately 25m from the Crèche play area. Taking into account the distance and screening from existing boundary treatments, activities from the crèche are calculated to be below 40dB L Aeq,1hr and hence, is well within the recommended daytime criterion of 50dB L Aeq,1hr and is also below the range of baseline noise levels recorded to the north of the site at Location N3, representing of properties set back from road traffic. The resultant noise impact is therefore not significant. Indirect Impacts The proposed development is not considered to contribute to any significant likely indirect noise or vibration impacts on its surrounding environment due to the nature of the development type which does not include any significant noise or vibration sources. In addition, the proposed development is in line with the existing surrounding environment and hence day to day activities including local access movements, children playing and pedestrian movements are fully in line with the existing baseline noise environment. 8-10

11 Cumulative Impacts The key potential noise source associated with the proposed development relates to additional traffic on the surrounding road network. The cumulative noise impacts associated with existing and development related traffic has been considered within this assessment and the impacts determined to be not significant. 8.6 Do Nothing Scenario Under the Do Nothing scenario, the prevailing noise environment at the closest noise sensitive locations will remain in line with those measured during the baseline study and hence will be of neutral effect in terms of noise. 8.7 Mitigation Measures Construction Phase With regard to construction activities, reference will be made to BS5228: Code of Practice for Noise and Vibration Control on Construction and Open Sites - Part 2 Vibration ( A1 2014). which offers detailed guidance on the control of noise and vibration from construction activities. Various mitigation measures will be considered and applied during the construction of the proposed development to ensure noise and vibration limit values are complied with, such as: Limiting the hours during which site activities likely to create high levels of noise or vibration are permitted; Establishing channels of communication between the contractor/developer, Local Authority and residents; Appointing a site representative responsible for matters relating to noise and vibration; Monitoring levels of noise during critical periods and at sensitive locations; All site access roads will be kept even so as to mitigate the potential for vibration from lorries. Furthermore, it is envisaged that a variety of practicable noise control measures will be employed. These will include: Selection of plant with low inherent potential for generation of noise and/ or vibration; Erection of barriers as necessary around items such as generators or high duty compressors; Siting of noisy plant as far away from sensitive properties as permitted by site constraints and the use of vibration isolated support structures where necessary. Erection of construction site hoarding along noise sensitive boundaries where works are taking place in close proximity to existing residential properties where no substantial screening exists. 8-11

12 8.7.2 Operational Phase During the operational phase of the development, noise mitigation measures with respect to the outward impact of the development are not deemed necessary. 8.8 Predicted Impacts of the Proposed Development Construction Phase During the construction phase of the project there is the potential for some minor impact on nearby noise sensitive properties due to noise emissions from site activities. The application of binding noise limits and hours of operation, along with implementation of appropriate noise and vibration control measures, will ensure that noise and vibration impact is kept to a minimum. The overall impact is determined to be shortterm and slight affecting a small number of local adjacent properties Operational Phase The predicted noise level associated with additional traffic is predicted to be of insignificant impact along the existing road network. In the context of the existing noise environment, the overall contribution of traffic is not considered to pose any significant impact to nearby residential locations. It can be concluded that, once operational, noise levels associated with the proposed development will not contribute any significant noise impact to its surrounding environment. The resulting impact is determined to be neutral, long-term and notsignificant. 8.9 Monitoring During the construction phase, spot check noise monitoring will be undertaken by the contractor to ensure construction noise limits are not exceeded. It is recommended that vibration monitoring is undertaken at the Wonderful Barn structure in the event that any significant intrusive works are taking place during the construction phase which have the potential to give rise to elevated vibration levels. During normal site preparation and house building activities, however, vibration monitoring is not deemed necessary Interactions In compiling this impact assessment, reference has been made to the project description provided by the project co-ordinators, project drawings provided by the project architects and traffic flow projections associated with the development provided by the traffic consultants. 8-12