Noise Impact Assessment

Transcription

1 Noise Impact Assessment December 2016 Prepared by SRL Technical Services Ltd

2 Telephone +44(0) Website London, Birmingham, Manchester, Sudbury Quality Assurance Project Title Document Title Client Client Address Author Checker Report Number Gillette South Noise Impact Assessment Access Self Storage Ltd 93 Park Lane London W1K 7TB David Harbon Ray Browne Additional information Revision History Revision Date Comments A 11/12/2015 Draft for client comment B 15/12/2015 Updated draft for client comment C 17/12/2015 General update D 02/12/2016 Updated draft for revised scheme E 14/12/2016 Final issue SRL Technical Services Limited Registered office: Holbrook House, Little Waldingfield, Sudbury, Suffolk, CO10 0TF Registered in England No

3 Summary SRL Technical Services Limited has been commissioned by Access Self Storage Ltd to complete a noise impact assessment for the proposed development at Gillette Corner, Great West Road, Hounslow, London. An attended noise survey was completed on Friday 21 August 2015 between 09:56-11:10 at 4 locations around the site. An unattended noise survey followed between Friday 21 August 13:00 and Tuesday 25 August :00. The impact of noise during the construction phase has been considered and an initial review of recommended Best Practicable Means (BPM) is provided. The noisiest façades overlooking A4 Great West Road and B464 Syon Lane will require high specification glazing and mechanical ventilation to achieve recommended internal ambient noise level criteria. Façades overlooking Northumberland Avenue will require high specification double glazing and acoustically attenuated ventilators. Quieter façades looking into the middle of the development will require standard double glazing and acoustically attenuated ventilators. However, glazing and ventilation specifications may be reduced for façades on higher storeys. This is subject to detailed design. If the offices use mechanical ventilation, standard double glazing will be sufficient to achieve the recommended internal ambient noise level criterion. Noise levels in the external roof amenity areas are expected to be within recommended criteria, when road traffic is the dominant noise source. However, noise levels will be elevated when aircraft are coming into land at Heathrow Airport from the east. Noise limits for all fixed plant are based on the assessment methodology set out in BS 4142:2014 Methods for rating and assessing industrial and commercial sound". Plant noise must be limited so that the rating noise level does not exceed the representative background noise level (L A90). Penalties to the rating noise level may apply dependent on the acoustic features of the noise. The M&E engineer must design plant installations to meet these guideline levels. Road traffic noise levels are not expected to significantly increase due to the already high current traffic flows on A4 Great West Road. As such the recommended glazing and ventilation specifications will attenuate external noise break-in to within guideline criteria. David Harbon For and on behalf of SRL Technical Services Limited Tel: dharbon@srltsl.com Ray Browne 14/12/2016 Page 3 of 24

4 Contents Summary Introduction Relevant Policy and Guidance Noise Survey Construction Noise Operational Noise Assessment Appendix A - Survey Details Appendix B - Survey Data Appendix C - Noise Measurement Parameter Definitions /12/2016 Page 4 of 24

5 1.0 Introduction Planning permission is sought for a mixed-use development at Gillette Corner. The scheme comprises residential, office and self-storage uses. The site is bounded by: A4 Great West Road and a Shell petrol station to the north; B464 Syon Lane and Homebase to the east; Northumberland Avenue and residential receptors to the south; and Adini Clothing Head Office and residential receptors at Warkworth Gardens to the west. The site red line boundary is shown in Figure 1 below. Figure 1: Red line boundary 14/12/2016 Page 5 of 24

6 2.0 Relevant Policy and Guidance Planning policy of relevance to noise and vibration matters is set out within the National Planning Policy Framework (NPPF), the London Plan and LBH Local Development Framework (LDF) documents. 2.1 Construction noise BS5228: 2009+A1:2014 Code of practice for noise and vibration control on construction and open sites gives recommendations for basic methods for prediction, measurement, and control of noise and vibration control relating to construction work. Methods for control of construction noise will be used to reduce construction noise impacts to the nearest sensitive receptors. 2.2 Noise levels for residential amenity and offices Guideline criteria for internal noise levels in living rooms and bedrooms are given in BS8233:2014 Guidance on sound insulation and noise reduction for buildings, and WHO Guidelines for Community Noise. The design of the facades and ventilation strategies will control external noise break-in to achieve the guideline criteria: 35 db L Aeq,16hour in living rooms; 30 db L Aeq,8hour in bedrooms; and 45 db L AFmax in bedrooms. Noise levels in external amenity spaces should not normally exceed the BS8233:2014 upper guideline value of 55 db L Aeq,T in noisier environments. Noise levels in open plan offices should be designed to db L Aeq,T. 2.3 Noise from fixed plant BS4142:2014 "Methods for rating and assessing industrial and commercial sound" describes methods for rating and assessing sound from fixed installations which comprise mechanical and electrical plant and equipment. The standard describes 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. Details of proposed plant is not known yet but is expected to be controlled by way of planning condition. Plant noise should be limited so that the rating noise level does not exceed the measured background level (L A90). 14/12/2016 Page 6 of 24

7 3.0 Noise Survey The noise survey comprised six measurement positions, as shown in Figure 2. Positions MP1-MP4 were attended measurement positions. MP5 was an unattended monitoring location. Figure 2: Monitoring positions A description of each measurement position is provided following; MP1: At 1m from the site hoarding at the junction of A4 Great West Road and B464 Syon Lane (northeastern boundary); MP2: At 1m from the site hoarding at the junction of B464 Syon Lane and Northumberland Avenue (south-eastern boundary); MP3: At 1m from the site hoarding on Northumberland Avenue (southern boundary); MP4: At 1m from the site hoarding on A4 Great West Road (north-western boundary); and MP5: At 2.5m above ground level (approx.). Monitor fixed to the site hoarding. All attended measurements were taken at a height of 1.5m above local ground level and were at 1m from the site hoarding, to simulate façade noise levels. Measurements at MP5 were under free-field conditions, (>3.5m away from reflecting surfaces). Measurements were 15 minutes in duration at each location. 14/12/2016 Page 7 of 24

8 The noise climate at each monitoring position comprised: MP1: - road traffic noise from A4 Great West Road and B464 Syon Lane - vehicles driving past, braking and pulling away at the junction; - car horns; and - aircraft noise. MP2: - road traffic noise from A4 Great West Road, B464 Syon Lane and Northumberland Avenue - vehicles driving past, braking and pulling away at the junction; - vehicles driving over a loose drain cover on B464 Syon Lane; - aircraft noise; - pedestrian conversation; - car radios; and - gulls calling. MP3: - Intermittent road traffic from Northumberland Avenue; - road traffic noise from A4 Great West Road and B464 Syon Lane; - turning aircraft; - distant sirens; - pedestrian activity; - birdsong; - leaves rustle; and - car door slams. MP4: - road traffic noise from A4 Great West Road; - car horns; - car radios; - sirens; - aircraft noise; - faint construction noise (during quieter periods) - pedestrian conversation; and - gulls calling. MP5: - road traffic noise from A4 Great West Road and B464 Syon Lane - vehicles driving past, braking and pulling away at the junction; - car horns; and - aircraft noise. 14/12/2016 Page 8 of 24

9 4.0 Construction Noise Detailed proposals of site construction operations are given in the Construction Management Plan. An initial review of Best Practicable Means (BPM) is provided below. The nearest sensitive receptors to this site are residential dwellings on Northumberland Avenue. Construction noise will be minimised using BPM to protect these receptors. Normal construction hours are as follows: Monday - Friday: 08:00-18:00hrs Saturdays: 08:00-13:00hrs No noisy activities outside of these hours, nor on Sundays or Bank Holidays is permitted unless otherwise agreed in writing with the Local Authority. 4.1 Noise and Vibration Mitigation - BPM Although the detailed site layout of construction equipment has not yet been determined, the following measures must be incorporated as best practice to minimise the potential for disturbance of residents. Site all noisy equipment away from noise sensitive areas; Do loading and unloading away from noise sensitive areas; Machinery should be started up sequentially rather than simultaneously; Machinery which is used intermittently should be shut down between work periods; Acoustic covers to engines must be kept closed when the engines are in use and idling; Use compressors that have effective acoustic enclosures and are designed to operate when their access panels are closed; Packaged generators where provided should have sufficient silencing such that they do not exceed the background noise level at the nearest residential property; Materials should be lowered and not dropped. Drop heights should be minimised where necessary; Regular and effective maintenance of machinery must be done; Where periods of higher noise levels above the desired target (see table E.2 of BS :2009+A1:2014) are anticipated, the residents should be informed by leaflet and given timescales over which the activities will occur and when they are expected to end; Where possible noisy works should only be carried out Mondays to Fridays 08:00 hours to 18:00 hours, and Saturdays 08:00 to 13:00 hours. No work (except emergency) should be done on Saturday afternoons, Sundays or Bank Holidays (unless agreed in writing with the Local Authority); Audits of site activities should be done at regular and frequent intervals during the construction program by a designated person to check that noise mitigation is being done. Sample noise level monitoring may also be done and recorded to demonstrate that noise is within acceptable limits; Doors and gates must not be located opposite sensitive receivers; 14/12/2016 Page 9 of 24

10 Personnel must be instructed on Best Practical Means to reduce noise and vibration as part of their induction training and as required prior to specific works; and Concrete pours must commence as early as possible to minimise the likelihood of overruns. 14/12/2016 Page 10 of 24

11 5.0 Operational Noise Assessment 5.1 Internal ambient noise levels Residential To achieve the recommended criteria of BS8233:2014 and WHO Guidelines, we recommend the glazing and ventilation strategies outlined in in Figures 3-5. It is best practice to design sound insulation so that noise levels in bedrooms during night-time periods do not normally exceed 45 db L AFmax. The glazing and ventilation strategies have therefore been designed to attenuate the 10th highest maximum noise level during the survey period to within the 45 db L AFmax criterion, i.e. 97 db L AFmax, rather than designing for the worst case maximum noise levels. However, this criterion may not be achieved for the lowest floors of the development fronting the A4 Great West Road, i.e. closest to the road. Figure 3: Main buildings glazing and ventilation strategies 14/12/2016 Page 11 of 24

12 Figure 4: Fourth to seventh floor glazing and ventilation strategies Figure 5: Seventh floor to roof glazing and ventilation strategies 14/12/2016 Page 12 of 24

13 The glazing and ventilation strategies and extent will be confirmed through detailed design. Upper floors may benefit from reduced glazing build-ups and ventilation requirements Office To achieve the recommended criteria of BS8233:2014 for offices, the minimum glazing performance is outlined in Table 5.2. Table 5.2: Office glazing Location Façade noise level dba Minimum glazing sound reduction R w db Example glazing build-up Façades facing Great West Road /12/6 It is assumed that offices will use mechanical ventilation. If alternate ventilation strategies are required, the glazing build-up may need to be changed to achieve higher sound insulation External wall construction The external walls will need to have a high sound insulation. Masonry will be adequate but if the facade is to be lightweight then this will need to be internally lined with acoustic insulation and two layers of dense acoustic plasterboard. 5.2 External noise levels in amenity spaces BS8233:2014 recognises that the criteria for noise levels in urban spaces may be difficult to achieve. The 55 db L Aeq,T criterion is appropriate for larger balconies, roof gardens and terraces, which might be intended to be used for relaxation. The criterion does not apply to small balconies. However 55 db L Aeq,T does not need to be achieved in all areas. "In high-noise areas, consideration should be given to protecting these areas by screening or building design to achieve the lowest practicable levels. Achieving levels of 55 db L Aeq,T or less might not be possible at the outer edge of these areas, but should be achievable in some areas of the space." There are rooftop amenity areas at podium level, fourth floor level and seventh floor level. These are understood to have a 1m balustrade to the perimeter. The predicted noise levels for each amenity area are shown in Figures 6-8. Areas marked orange or red are above the BS8233 recommendations. Areas marked in grey are above the lower guideline value of 50 db L Aeq,T but below the upper guideline value of 55 db L Aeq,T. Areas marked in green or yellow are below the 14/12/2016 Page 13 of 24

14 lower guideline value of 50 db L Aeq,T. The majority of the amenity spaces are either below or within the BS8233 recommendations. Figure 6: Predicted podium level amenity noise levels Figure 7: Predicted fourth floor level amenity noise levels 14/12/2016 Page 14 of 24

15 Figure 8: Predicted seventh floor level amenity noise levels The site sits within the 57 db L Aeq,16hour to 60 db L Aeq,16hour contours for Heathrow Airport due to aircraft coming into land from the east. Therefore noise levels in the roof garden area are expected to achieve the 55dB L Aeq,T recommendation when road traffic is the dominant noise source, but noise levels will be elevated when aircraft are coming into land at Heathrow Airport from the east. This is typical of an urban location. If residents require an external area for relaxation, it is likely that the podium level garden will be used, which will benefit from reduced noise levels due to greater screening by the proposed structures. 5.3 Plant noise Noise emissions from fixed plant installations associated with the new development will need to be controlled to within guideline criteria. The measured L A90 levels represent the background noise level at the site. The L A90 can be used to set plant noise limits at the site so that the impact of fixed plant noise on local receptor properties is controlled. It is expected that based on current guidance in BS4142:2014, the measured or calculated rating level of the cumulative effect of the noise emitted from fixed plant installations will be required to not exceed the representative background noise level (L A90). Penalties may apply if there is a particular tonal or discrete acoustic feature to the noise. The lower the rating level is relative to the measured background sound level, the less likely it is that the plant noise emissions will have a significant adverse impact. Where the rating level does not exceed the 14/12/2016 Page 15 of 24

16 background sound level, this is an indication of the specific sound source having a low impact, depending on the context. There will be a plant room on Basement Level 1, and vent to the ground floor in the north-western corner of the site. There will also be transformer and generator rooms at ground floor level in the north-western corner of the site. It will be beneficial to have the majority of plant venting to noisier façades, as it will be easier to achieve the rating noise level criteria, and there is less risk of significant effects at the nearest noise sensitive receptors. The plant room is expected to be the main source of noise emissions to atmosphere. Transformers are typically low noise items, and its noise emissions will be attenuated by louvred doors. It is expected that the generator will be used as a standby generator, and so will only operate in the event of power failure. The noise emissions should be confirmed by an acoustic consultant, once the equipment has been selected, to ensure that there are no acoustic features to the noise, e.g. tonal features, that are likely to cause disturbance. BS4142:2014 states that a representative background noise level should be used for assessment, and in this case, to set appropriate rating noise levels. A representative level should account for the range of background sound levels and should not be assumed to be either the minimum or modal value. To set the rating levels, the 95th percentile of the L A90 values from the unattended noise survey has been taken as the representative background noise level. The total rating level contribution of plant noise emissions should not exceed the design rating levels shown in Table 5.3. Table 5.3: Plant noise limits to be met at the closest sensitive receptors Period Design rating level L Ar db Daytime (07:00-23:00) 56 Night-time (23:00-07:00) 49 If all plant is designed to achieve the night-time rating level, the daytime criterion will be met by default. When designing the plant installations, the methodology of sections 9.2 and/or 9.3 of BS4142:2014 for subjective and objective methods of assessing the rating level, should be adopted. These methodologies will allow the rating level penalty to be determined for the acoustic features of the noise. Rating level penalties of 0dB to 9dB may be appropriate depending on the tonality, impulsivity, distinction and intermittency of the noise. Agreement to the proposed penalty with the Local Authority should be sought once the acoustic features of the noise are understood. 14/12/2016 Page 16 of 24

17 5.4 Road traffic Due to high road traffic flows on Great West Road and the local road network, road traffic flows are not expected to significantly increase (more than 25%) with the proposed development. As such, noise levels are not expected to significantly increase at the façade locations. The recommended façade glazing and ventilation recommendations will control noise break-in to within recommended criteria. 14/12/2016 Page 17 of 24

18 Appendix A - Survey Details A1. Location of Survey Gillette South development site Junction of A4 Great West Road and B464 Syon Lane. A2. Date & Time of Survey Attended survey Friday 21 August 2015, 09:56-11:10 Unattended survey Friday 21 August 2015, 13:00 - Tuesday 25 August 2015, 12:00. A3. Personnel Present During Survey David Harbon MSc MIOA, SRL Technical Services Ltd. A4. Weather Conditions during Survey Attended survey Dry, sunny, 50% overcast, ~17 C. Unattended survey Friday 21 August 2015 Dry, sunny, 50% overcast, ~17 C. Unattended Mainly dry, with wind speeds generally below 5m/s, in variable direction. Periods of light showers occurred on Sunday 23 and Monday 24 August Tuesday 25 August 2015 Dry, overcast, ~17 C. 14/12/2016 Page 18 of 24

19 A5. Instrumentation Norsonic Nor140 Type 1 Sound Level Meter (SRL 778) (serial No: ) Nor-1251 Acoustic Calibrator (SRL 870) (serial No: 34428) A6. Calibration Procedure Before and after the survey the measurement apparatus was check calibrated to an accuracy of ±0.3 db using the Nor-1251 Sound Level Calibrator. The Calibrator produces a sound pressure level of 114 db re 2 x 10-5 Pa at a frequency of 1 khz. A7. Survey Procedure Ambient noise levels were monitored at various positions around the site as shown on Figure 1. The measurements are tabulated in Appendix B, and explanations of the parameters used are listed in Appendix C. 14/12/2016 Page 19 of 24

20 Appendix B - Survey Data Attended Survey - Measured Ambient Noise Levels Position Time L Aeq L AFmax L A90 L A10 MP1 09:56-10: MP2 10:19-10: MP3 10:36-10: MP4 10:55-11: Attended Survey - L A90 Octave Band Levels Pos Time k 2k 4k db(a) MP1 09:56-10: MP2 10:19-10: MP3 10:36-10: MP4 10:55-11: /12/2016 Page 20 of 24

21 Unattended Survey - Measured Ambient Noise Levels Date Period Average L Aeq Maximum L AFmax Average L A90 Minimum L A90 (time occurring) Friday 21/08/15 Daytime (13:00-19:00)* Evening (19:00-23:00) Night-time (23:00-07:00) Saturday 22/08/15 Daytime (07:00-19:00) Evening (19:00-23:00) Night-time (23:00-07:00) Sunday 23/08/15 Daytime (07:00-19:00) Evening (19:00-23:00) Night-time (23:00-07:00) Monday 24/08/15 Daytime (07:00-19:00) Evening /12/2016 Page 21 of 24

22 Date Period Average L Aeq Maximum L AFmax Average L A90 Minimum L A90 (time occurring) (19:00-23:00) Tuesday 25/08/15 Night-time (23:00-07:00) Daytime** (07:00-12:00) *Not full daytime measurement (13:00-19:00) ** Not full daytime measurement (07:00-12:00) 14/12/2016 Page 22 of 24

23 Appendix C - Noise Measurement Parameter Definitions L A90 - The "A" weighted sound pressure level that is exceeded for 90% of the measurement period. It is commonly used as the "Background Noise Level". L A10 - The "A" weighted sound pressure level that is exceeded for 10% of the measurement period. This is often used for assessing traffic noise. L Aeq - The "A" weighted equivalent continuous sound pressure level. A representation of a continuous sound level containing the same amount of sound energy as the measured varying noise, over the measurement period. It can be considered as the "average" noise level. L AFmax - The maximum "A" weighted sound pressure level during the measurement period. 14/12/2016 Page 23 of 24

24 Sudbury Consultancy Manchester Consultancy London Consultancy Holbrook House Lynnfield House Citypoint Building - 12th Floor Little Waldingfield Church Street 1 Ropemaker Street Sudbury Altrincham London Suffolk Cheshire EC2Y 9HT CO10 0TF WA14 4DZ Tel: +44 (0) Tel: +44 (0) Tel: +44 (0) Birmingham Consultancy South Africa Consultancy Laboratory Cornwall Buildings Ground Floor, Liesbeek House The Street 45 Newhall Street River Park Little Waldingfield Birmingham Gloucester Road Sudbury B3 3QR Mowbray Suffolk Tel: +44 (0) C010 0TF South Africa Tel: +44 (0) Tel: +27 (0) Website: srl@srltsl.com SRL offers services in: Acoustics Air Quality Air Tightness BREEAM Compliance Fire Laboratory and Site Testing Registered Name and Address: SRL Technical Services Limited Holbrook House Little Waldingfield Sudbury Suffolk CO10 0TF Registered Number: England 14/12/2016 Page 24 of 24