PROPOSED PLAN CHANGE: ALEXANDER ROAD UPPER HUTT. Noise Assessment. Rp W. 27 July 2012

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1 PROPOSED PLAN CHANGE: ALEXANDER ROAD UPPER HUTT Noise Assessment Rp W 27 July 2012

2 Level 2 5 Willeston Street PO Box Panama Street Wellington 6146 New Zealand T: F: Project: PROPOSED PLAN CHANGE: ALEXANDER ROAD UPPER HUTT Prepared for: Alexander Road Developments Ltd PO Box Lower Hutt 5040 Attention: Chris Mason Report No.: Rp W Disclaimer Reports produced by Marshall Day Acoustics Limited are prepared based on the Client s objective and are based on a specific scope, conditions and limitations, as agreed between Marshall Day Acoustics and the Client. Information and/or report(s) prepared by Marshall Day Acoustics may not be suitable for uses other than the original intended objective. No parties other than the Client should use any information and/or report(s) without first conferring with Marshall Day Acoustics. Copyright The concepts and information contained in this document are the property of Marshall Day Acoustics Limited. Use or copying of this document in whole or in part without the written permission of Marshall Day Acoustics constitutes an infringement of copyright. Information shall not be assigned to a third party without prior consent. Document control Status: Rev: Comments Date: Author: Reviewer: Draft For discussion 05/06/12 B. Wood S. Arden Draft 2 For discussion 14/06/12 B. Wood S. Arden Draft 3 For discussion 03/07/12 B. Wood S. Arden Draft 4 For review 20/07/12 B. Wood S. Arden Approved 27/07/12 B. Wood S. Arden

3 EXECUTIVE SUMMARY Marshall Day Acoustics has been engaged by Alexander Road Developments Ltd to provide an environmental noise assessment of a proposal to subdivide, develop and use a section of land adjacent to Alexander Road, Upper Hutt, for residential activity. The land is currently zoned Business Industrial in the Upper Hutt District Plan. The adjoining land to the southwest is also zoned Business Industrial. The subject site is bounded along its north-western boundary by Alexander Road, and the land on the opposite side of Alexander Road is zoned Special Activity. This land is currently owned by AgResearch Ltd for animal grazing purposes. There is little noise-generating activity occurring on the adjoining Business Industrial land to the southwest. This is largely undeveloped, with the exception of a relatively new concrete building located near the south-western boundary of the subject site and close to Alexander Road. Another large industrial building, which appears to function as a warehouse, is located some 140 metres further to the southwest. There is a possibility that at some future stage this adjoining Business Industrial land could be developed for Industrial purposes. Should the proposal to develop the subject site for residential activity be accepted, and the plan change request granted, this report recommends various measures to avoid the reverse sensitivity issues which may prevent an adjacent Business Industrial user from carrying out an otherwise legitimate activity, due to limits on industrial noise received at residential boundaries. This therefore would also protect residential amenity and provide sufficient protection for future Business Industrial activities. It is considered that if the measures recommended in this report are implemented, the resultant noise levels at the subject site would be suitable for residential use. Page 3 of 21

4 TABLE OF CONTENTS 1.0 INTRODUCTION SITE ACOUSTICAL CONSIDERATIONS OF THE PROPOSAL NOISE PERFORMANCE STANDARDS ASSESSMENT OF EFFECTS BUSINESS INDUSTRIAL NOISE ASSESSMENT OF EFFECTS TRAFFIC NOISE CONSTRUCTION NOISE DISCUSSION CONCLUSIONS APPENDIX A GLOSSARY OF TERMINOLOGY APPENDIX B NOISE MEASUREMENT LOCATIONS APPENDIX C MEASURED NOISE LEVELS APPENDIX D NOISE CONTOURS: CUMULATIVE BUSINESS INDUSTRIAL AND TRAFFIC Page 4 of 21

5 1.0 INTRODUCTION Marshall Day Acoustics (MDA) has been engaged by Alexander Road Developments Ltd to provide an environmental noise assessment of a proposal to subdivide, develop and use a section of land adjacent to Alexander Road, Upper Hutt, for a residential activity. Currently, the subject site has been subdivided for business/industrial development. This report addresses noise in the Assessment of Environmental Effects which will accompany the Plan Change request. 2.0 SITE 2.1 Zoning The subject site is currently zoned Business Industrial in the Upper Hutt District Plan (the District Plan). The adjoining land to the southwest is also zoned Business Industrial. Adjoining land to the south east is zoned Rural Hill. To the east and northeast the land is zoned Rural Hill and Rural Lifestyle. The subject site is bounded along its northwestern boundary by Alexander Road. The land on the opposite side of Alexander Road to the subject site is zoned Special Activity, and is currently owned by AgResearch Limited, and is used for animal grazing. Figure 1 shows the location of the subject site within the District Plan zoning map. Figure 2 shows the site in more detail. Subject site Alexander Rd Adjoining Business Industrial land Figure 1: Location of subject site (source: Upper Hutt District Plan Rural Maps 24 and 25) Page 5 of 21

6 Figure 2: Subject site, approximate boundary outlined in red. (Source: UHCC GIS) 2.2 Topography In general, the subject site is reasonably flat. Its ground level (GL) is approximately 1.4 to 1.5m higher than the GL of the adjoining Business Industrial land to the southwest. This adjoining Business Industrial land is also flat. 2.3 Current Activity Two site inspections were carried out by Marshall Day Acoustics. The first was on Tuesday 10 April 2012, and the second one took place on Thursday 28 June During the second site visit, a series of noise measurements was made, generally in accordance with NZS 6801:1991. Observations made during the site visit indicate that the current main source of noise received across the subject site is traffic on Alexander Road. At the time of the site inspections, it was noted that the adjoining Business Industrial land is largely undeveloped, with the exception of a relatively new concrete building located near the south-western boundary of the subject site and close to Alexander Road. There was little Page 6 of 21

7 noise associated with this building, although there are two generator sets (assumed to be emergency generators), two small transformers, a fuel tank and a number of air-cooled condensers located at the rear of the building close to the boundary of the subject site. At the time of the measurements, the generators and transformers were not operating, but a number of the condensers were. It was noted that at the time of the second site visit, there was some contribution from the air-cooled condensers to the noise environment close to this location. However, the dominant noise source was still considered to be traffic on Alexander Road. The measurements indicate that this equipment is currently compliant with the relevant District Plan daytime criterion of 65 dba L 10. Another large industrial building is located some 140 metres to the southwest. This building is currently being used by the New Zealand Ministry of Defence, and appears to function as a warehouse. Noise sources here consisted of occasional forklift reversing alarms and occasional truck movements. These made little contribution to the overall noise levels measured on the subject site Site noise levels Noise level measurements made on 28 June 2012 showed that the noise levels are typically: 66 dba L 10, 61 dba L eq and 45 dba L 95 on the land closest to Alexander Road; 53 dba L 10, 50 dba L eq and 44 dba L 95 at the approximate midpoint of the site; and 48 dba L 10, 46 dba L eq and 40 dba L 95 close to the rear of the site. The noise level measured close to the site boundary with the adjoining Business Industrial land, and adjacent to the closest industrial building and ancillary plant items detailed above, was 63 dba L 10, 60 dba L eq and 48 dba L 95. As noted above, the main contributor to these measured noise levels was traffic on Alexander Road. Appendix B details the noise measurement positions, and Appendix C contains the details of the site measurements. 3.0 ACOUSTICAL CONSIDERATIONS OF THE PROPOSAL 3.1 Adjoining Land North and Northeast In terms of noise, the proposed Plan Change would amend the noise criteria for the subject site from Business Industrial to Residential. This would have no adverse effect at the northeastern and south-eastern boundaries, as the adjoining land is zoned either Rural Lifestyle or Rural Hill. These share the same District Plan noise criteria as land zoned Residential. Should the proposal obtain consent, there is some potential for benefit to the adjoining Rural zone, due to the similarity of noise rules for Rural Lifestyle, Rural Hill, and Residential zones. Page 7 of 21

8 3.2 Adjoining Business Industrial Land The Business Industrial land adjoining the subject site has a significantly higher noise limit than Residential zoned land. Consequently, mitigation measures are required to avoid reverse sensitivity issues arising, as well as to ensure a reasonable level of residential amenity within the subject site. 3.3 Special Activity Land The land on the opposite side of Alexander Road to the subject site is zoned Special Activity, which shares the same District Plan noise criteria as the land zoned Business Industrial. However, this land is currently owned by AgResearch for animal grazing purposes, and there is no significant continuous source of noise on this land. The District Plan notes that activities on this land may include field days. On such occasions there may be sporadic noisy events, but these would be irregular. In order to establish a consistent potentially noisy industrial activity on this land, either a Resource Consent that allows this activity, or a plan change, would be required to change its zoning from Special Activity to Business Industrial. At this stage this has not occurred and so, consistent with its current zoning, it is considered that this land would not be a source of noise requiring mitigation. 3.4 Alexander Road Alexander Road is currently surfaced with chipseal, with a short section of asphaltic concrete (AC) in the northeast bound lane adjacent to the subject site s northwestern boundary. The area of the subject site closest to Alexander Road is exposed to relatively high levels of traffic noise. 4.0 NOISE PERFORMANCE STANDARDS 4.1 Upper Hutt District Plan The District Plan has noise rules that are designed to control noise emissions from various activities. Chapter 32 contains the permitted activity noise criteria for the various environmental zones as defined in the Plan. Section 32.5 Noise from all other activities contains the relevant noise rules. These are as follows: Page 8 of 21

9 Mon to Sat 7:00am 7:00pm All other times, Sundays & public holidays dba L 10 L max L 10 L max Maximum noise levels measured at or within the boundary of any site (other than the source site) in the Residential, Rural and Open Space Zones. Maximum noise levels measured at or within the boundary of any site (other than the source site) in the Business and Special Activity Zones Notes Noise levels shall be measured in accordance with the requirements of NZS 6801:1991 Measurement of Sound, and assessed in accordance with the requirements of NZS 6802:1991 Assessment of Environmental Sound. Noise levels shall be measured with a sound level meter complying with International Standard IEC (1979): Sound Level Meters, Type 2. Adjustments for special audible characteristics, if present, as provided for in clauses 4.3 and 4.4 of NZS 6802:1991, shall apply and will have the effect of imposing a maximum permitted noise level 5dBA more stringent than the L 10 levels stated above. This condition shall not apply to impulse noise emissions arising from firing and detonation activities at the Trentham Ranges. The definitions of dba, dbc, L 10 and L max are those found in NZS 6802: Limits of Acceptability - Residential Daytime World Health Organisation (WHO) guidelines 1 note that during daytime, few people are highly annoyed at noise levels below 55 dba L eq. The guidelines further recommend that in order to protect the majority of people from being seriously annoyed during daytime, the outdoor sound level from steady continuous noise should not exceed 55 dba L eq in outdoor living areas. These findings are consistent with the recommendations in New Zealand Standard NZS 6802:1991 Assessment of Environmental Sound. This Standard provides guidelines for the reasonable protection of health and amenity associated with use of land for residential 1 Community Noise ed. B. Berglund, T. Lindvall, D H Schwela (prepared for World Health Organisation), 1999 Page 9 of 21

10 purposes. These limits are 55 dba L 10 during the day and 45 dba L 10 at night-time. The more recent New Zealand Standard NZS 6802:2008 Acoustics - Environmental Noise recommends similar upper limits. It is noted that the NZS 6802 limits are for use in situations where there are no performance standards. In this case the District Plan has noise rules for both Residential and Business Industrial zones, and the NZS 6802 recommended daytime noise limit of 55 dba L 10 represents a 5 db relaxation of the District Plan Residential zone daytime limit. However in situations where achieving compliance with the District Plan daytime criterion of 50 dba L 10 may be impracticable, and based on the WHO findings and the guidance from NZS 6802, it is considered that this relaxed daytime limit would still provide residents on the subject site with a reasonable level of residential amenity, and would protect people from being seriously annoyed during daytime Night time The District Plan daytime noise limits for both the Business Industrial and the Residential zones extend from 7am to 7pm. It is recommended that any relaxation of the Residential limit would apply to the Daytime hours only. It is not intended that the night-time limits be relaxed, but would remain as set out in the District Plan, which are 45 dba L 10 in the Business Industrial zone, and 40 dba L 10 in the Residential zone. 5.0 ASSESSMENT OF EFFECTS BUSINESS INDUSTRIAL NOISE Currently the Business Industrial establishment closest to the common boundary of the adjoining Business Industrial land and the subject site is the new concrete building and associated plant, as described in Section 2.3 of this report. The following assessment has assumed that the noise from this plant is compliant with the relevant noise criteria of the District Plan. There is no specific requirement for noise from emergency generation equipment apart from the District Plan criteria as discussed in Section 4.1 of this report. Consequently it would be expected that the noise from this equipment would be suitably mitigated to ensure compliance. However, if no additional mitigation has been implemented there is potential for the generator noise from time to time to exceed the District Plan criteria, at times by a substantial margin. For this assessment, the modelling has assumed a typical generator sound power and spectrum. In addition to this plant, there is no way of knowing what other activities might eventuate within the adjoining Business Industrial land. For the purposes of assessing the effects of this proposal, the scenario of many industrial sources adjacent to the subject site southwest boundary, each producing noise at the upper limit of the 65 dba L 10 District Plan daytime Business Industrial criterion was considered. These sources include the existing plant associated with the new building. For the modelling, each remaining source has been located approximately equidistant between the north eastern and south western Business Industrial site boundaries. This location is a Page 10 of 21

11 conservative approach, as the closer the source is to either boundary, the quieter it needs to be to comply with the District Plan criteria. Source height has been assumed to be between 3 m and 4 m above ground. This overall scenario represents a conservative approach, given that many Business Industrial activities are typically warehousing, storage, and other such activities which generally produce little noise. In carrying out our prediction of noise we have constructed a noise model using SoundPLAN. SoundPLAN is internationally recognised software which can be used to predict noise levels via a range of international standards. In order to calculate environmental noise from industrial sources we have used ISO :1996 Acoustics Attenuation of sound during propagation outdoors Part 2: General method of calculation. For assessment of the noise from traffic on Alexander Road, we have used the Calculation of Road Noise model (CRTN) as prepared by the Department of Transport, United Kingdom, and validated for New Zealand use. Note that the following predicted noise levels are for single storey houses only, and for noise received at ground level within the property. This is to ensure the protection of residential amenity within the properties of the potentially most exposed houses. Noise levels received at the upper levels of any two-storey houses are discussed in Section of this report. 5.1 Noise Mitigation Mitigation measures would be required to avoid the reverse sensitivity issues which may prevent a Business Industrial user from carrying out an otherwise legitimate activity, due to limits on industrial noise received at residential boundaries. These would therefore protect residential amenity and provide sufficient protection for Business Industrial activities. An appropriately designed barrier would provide such protection. This barrier can consist of a solid wall, or a combination of earth bund and wall on top. To be effective, this acoustical barrier must be constructed from material with a minimum surface density of 12 kg/m 2 such as 25mm thick timber, Hardies compressed sheet, or materials of equal or greater density, including concrete panels. There must be no gaps between barrier panels and no gap between the bottom of the barrier and the ground. The following comments are based on the assumption that the existing ground level (GL) difference between the subject site and the adjoining Business Industrial land will remain. The subject site is approximately 1.4 higher than the GL of the Business Industrial land, and the difference in ground levels occurs just within the boundary fence line on the subject site side. If houses are to be constructed between this common boundary and William Durant Drive, the total barrier height would need to be 5 metres, with a resultant 3.6m high barrier on the subject site side. This would enable the noise from the Business Industrial site to be within the 55 dba L 10 criterion, as discussed in Section 4.2 of this report, at ground level. Page 11 of 21

12 5.1.1 Two-Storey Construction If two-storey houses are constructed between William Durant Drive and the Business Industrial boundary, Business Industrial noise levels received at the upper level are predicted to be 3 to 5 db higher than those predicted for ground floor level. For a 5/3.6m high barrier, Business Industrial noise levels could at times be 60 dba L 10 at the upper level façade of a two storey house. The District Plan daytime hours for the higher noise limits from the Industrial Zone apply between 7am to 7pm. The noise limits then reduce to 45 dba L 10 for all other times, Sundays and public holidays. However, there is potential for occasionally noisy events such as emergency generator operations during the night-time hours. In this case the generator plant should be appropriately treated in order to meet the District Plan night-time noise criterion. This assessment has not assumed that this would always be the case. Additionally, there may be those in the near 2-storey houses with atypical sleep patterns (such as shift workers). For these reasons it would be useful for the upper level to have additional sound insulation designed into the upper level construction. A requirement for additional sound insulation for upper levels of any two-storey houses between the adjoining Business Industrial area and William Durant Drive could usefully be incorporated as a zoning requirement of the Plan Change. An example of this would be the requirement that the external sound insulation for any habitable room used for a noise sensitive activity be designed to achieve D ntw + C tr > 30 db. Essentially this would enable a 30 db reduction from outside to inside. For the upper level of a house receiving up to 60 dba L 10 from the Business Industrial area, this would equate to 30 dba L 10 within the habitable room. This level of sound insulation is not onerous or difficult to achieve. In order to meet the requirement with windows closed, an alternative means of ventilation must be provided in accordance with the Building Act ASSESSMENT OF EFFECTS TRAFFIC NOISE Alexander Road is currently surfaced with chipseal, and a small section of asphaltic concrete (AC) near the subject site. Current traffic noise levels within the subject site have been calculated as ranging from 60 dba L eq(24h) adjacent to Alexander Road, to 50 dba L eq(24h) midway between Alexander Road and the rear of the site, and 40 dba L eq(24h) at the rear of the site. These calculations are consistent with the site noise measurements carried out on the 28 th June Traffic noise is normally assessed differently from other environmental noise. This is because of its largely continuous nature and because it is generally tolerated to a somewhat greater degree than other noise. To put it into perspective, NZS 6806 "Acoustics - Road-traffic noise - New and altered roads" recommends that where practicable, noise from a new road should not exceed 57 dba L eq(24h) (category A); or where it is inconsistent with the best practicable Page 12 of 21

13 option (BPO) to achieve this criterion, the criterion of Category B would apply. This is 64 dba L eq(24h). These NZS 6806 criteria for new roads are the most stringent of the Standard. As Alexander Road is neither a new or altered road, NZS 6806 is not technically applicable. However, for this proposal, it can provide guidance as to the acceptability of traffic noise. Because the proposed subdivision would be a new residential site, the most stringent criteria, those for new roads should be adopted for guidance. 6.1 Mitigation of Traffic Noise With Alexander Road in its current condition, the most exposed properties would receive no more traffic noise than many other properties around New Zealand in similar situations. In many cases these other properties do not have specific mitigation for the traffic noise. In this case, it is proposed that a varied series of barriers 2 metres in height be installed as shown in the Moorhead & Newdick layout documentation. These barriers are all 2 metres in height, and consist of a range of various constructions including river stone faced walls, concrete block, and timber with planting. We recommend that the design be supplemented with a return at the northeastern end of the barriers in order to adequately screen the northernmost property from the traffic noise. The following comments are based on that recommendation being implemented. The current traffic volume on Alexander Road is 4,600 vehicles per day, with up to 3% heavy trade vehicles. It has been predicted that the proposed development would increase traffic on Alexander Road by an additional 1,800 vehicles per day. This increased traffic flow has been taken into account in the following predictions. Note that at this stage, the barrier effect of rows of houses has not been included in the predictions. In reality each row of houses will provide a degree of acoustical screening to each successive row. This assessment is therefore focused on the effects for the properties fronting on to Alexander Road as they would be most exposed to traffic noise. The traffic noise, and therefore any adverse effects, for each successive row of houses would be reduced compared to those of the most exposed houses Barriers and Existing Surface With barriers installed as shown in the Moorhead & Newdick layout documentation, the traffic noise level is predicted to be within the 64 dba L eq(24h) criterion of Category B, although approaching its upper limit. In such a case, designing sound insulation into the houses would be an option. An alternative approach might be to design the houses so that the habitable spaces are away from the road. However, either option still leaves an impacted outdoor area with reduced outdoor amenity. Page 13 of 21

14 6.1.2 Asphaltic Concrete on Alexander Road With an AC road surface and the barriers as designed, the traffic noise level at the closest houses is predicted to be within the most stringent 57 dba Leq(24h) Category A criterion of NZS 6806 at ground level within the properties, but would marginally exceed that criterion at the top of the house windows. Note that in order to be effective for all houses along the Alexander Road frontage, the AC should extend 50 metres beyond the site at both sides Open Graded Porous Asphalt on Alexander Road With an OGPA road surface and the barriers as designed, the traffic noise level at the closest houses is predicted to be within the most stringent Category A criterion of NZS The resultant traffic noise level would therefore be considered to be suitable for residential use. Note that in order to be effective for all houses along the Alexander Road frontage, the OGPA should extend 50 metres beyond the site at both sides. 7.0 CONSTRUCTION NOISE The District Plan requires that noise resulting from construction, maintenance and demolition activities shall not exceed the following: Mon to Sat 7:00am 7:00pm: 75 dba L eq and 90 dba L max ; and All other times, Sundays and public holidays: 45 dba L eq and 75 dba L max. The District Plan requires that noise levels shall be measured and assessed in accordance with the requirements of New Zealand Standard NZS 6803: 1999 Acoustics - Construction Noise. MDA has not seen a construction schedule for the proposed site. However, it is likely that for conventional construction methods operating within normal operating hours, construction activities can generally comply with the relevant District Plan construction noise criteria. 8.0 DISCUSSION 8.1 Sleep Disturbance Australian/New Zealand Standard AS/NZ 2107:2000 Acoustics - Recommended design sound levels and reverberation times for building interiors sets out recommended design sound levels for living and sleeping areas for residential buildings. For this situation, the Standard recommends an internal design sound level of between 30 and 35 dba L eq for the sleeping areas of houses near minor roads. Page 14 of 21

15 New Zealand house construction typically provides up to 20 db reduction from outside to inside, with the windows closed. With windows slightly ajar, a reduction from outside to inside of 15 db can be expected. Noise from industrial sources is typically steady state noise. In such cases the L 10 and L eq descriptors tend to converge, with the L 10 value being only 1 or 2 db higher than the L eq value. Consequently, without additional insulation designed into a house, an incident nighttime noise level of 40 dba L 10 on the outside of a house would result in an internal noise level of 18 to 19 dba L eq with the windows closed, and 23 to 24 dba L eq with the windows partially open. These levels are all within the recommended design sound level of AS/NZS The recommendations of AS/NZS 2107 are consistent with research reported by the Archives of the Centre for Sensory Research on Community Noise (1995) for the World Health Organisation (WHO). This details findings into sleep disturbance, and states that.the equivalent continuous sound pressure level during the sleeping period should not exceed db L Aeq for continuous noise indoors. In the case of fluctuating noise, the maximum level is best correlated to sleep disturbances. The higher District Plan daytime noise limits extend from 7am to 7pm, for both Business Industrial and Residential areas. Between 7pm and 7am the next morning, as well as for all day Sundays and public holidays, the noise limit is so low as to preclude much activity in the Business Industrial area. In any event, the recommended noise mitigation would be equally effective in reducing the night time external noise level to within the District Plan night-time residential area criterion of 40 dba L 10. This would provide adequate protection from sleep disturbance. Section of this report recommends the additional sound insulation on the external facade of the upper level of habitable rooms of any two-storey houses located between the Business Industrial boundary and William Durant Drive. The recommended sound insulation would ensure that the Business Industrial noise level in bedrooms would be within the recommendations of AS/NZS 2107 at all times. 8.2 Traffic Noise The NZS 6806 approach to mitigation of traffic noise is based on the BPO, as discussed above in Section 6.0 of this report. In this case, traffic noise compliance with either Category A (57 db L Aeq(24h) or less) or Category B (57 to 64 db L Aeq(24h) ) is considered to provide a noise environment suitable to for residential use. Use of AC and barriers would result in traffic noise either at, or marginally in excess of, the upper limit of Category A. This would be considered generally to be suitable for residential use. However, the use of OGPA would result in traffic noise within the most stringent Category A criterion of NZS It is recommended that the use of this road surface be investigated. Page 15 of 21

16 8.3 Cumulative Effects Measures have been discussed for limiting industrial noise received within the subject site. Measures have also been recommended which limit traffic noise intrusion to the properties most exposed to Alexander Road, in order to provide a resultant traffic noise level considered to be suitable for residential use. To assess the cumulative effect of both noise sources is difficult because the effect of traffic noise on a general population is different from that of industrial noise. However, by combining the L 10 traffic noise level with the L 10 industrial noise level, an indication of the combined noise levels across the site can be arrived at. This is an indication only as the screening effect of rows of houses cannot at this stage be fully accounted for. As an approximation of this effect several rows of houses have been modelled in indicative locations. As an example, Figure D1 of Appendix B shows the noise contours resulting from Alexander Road traffic on an OGPA road surface, with the barriers constructed as discussed. This traffic noise has been combined with the noise from the Business Industrial scenario, with a 5m high barrier on the southwest boundary of the subject site. Figure D1 shows that with both sources combined, noise levels across the site are predicted to range generally between 45 and 55 dba L 10 and to a large extent each noise source is separate, without contributing significantly to the other. 9.0 CONCLUSIONS Marshall Day Acoustics has been engaged by Alexander Road Developments Ltd to provide an environmental noise assessment of a proposal to subdivide, develop and use a section of land adjacent to Alexander Road, Upper Hutt, for residential activity. This land is currently subdivided for business/industrial development. This report recommends various measures to avoid the reverse sensitivity issues which may prevent an adjacent Business Industrial user from carrying out an otherwise legitimate activity, due to limits on industrial noise received at residential boundaries. This therefore would also protect residential amenity and provide sufficient protection for Business Industrial activities. Such measures include: An acoustical barrier and/or buffer zone to the southwest of the site; Acoustical barriers adjacent to Alexander Road; Additional sound insulation for the upper levels of any houses between the Business Industrial boundary and William Durant Drive; and for the upper levels of any houses between Alexander Road and Thomas Neal Drive; and Page 16 of 21

17 Resurfacing a section of Alexander Road with a quiet road surface. It is considered that with these measures implemented, the resultant noise levels at the subject site would therefore be considered to be suitable for residential use. Page 17 of 21

18 APPENDIX A GLOSSARY OF TERMINOLOGY db Decibel The unit of sound level. Expressed as a logarithmic ratio of sound pressure P relative to a reference pressure of Pr=20 µpa i.e. db = 20 x log(p/pr) dba A-weighting L eq L eq (t) The unit of sound level which has its frequency characteristics modified by a filter (A-weighted) so as to more closely approximate the frequency bias of the human ear. The process by which noise levels are corrected to account for the non-linear frequency response of the human ear. The equivalent continuous (time-averaged) sound level. This is commonly referred to as the average noise level. The equivalent continuous (time-averaged) sound level. This is commonly referred to as the average noise level. The suffix "t" represents the time period to which the noise level relates, e.g. (24 h) would represent a period of 24 hours, (15 min) would represent a period of 15 minutes and ( ) would represent a measurement time between 10 pm and 7 am. L 95 L 10 D nt,w The noise level equalled or exceeded for 95% of the measurement period. This is commonly referred to as the background noise level. The noise level equalled or exceeded for 10% of the measurement period. This is commonly referred to as the average maximum noise level. Weighted Standardised Level Difference A single number rating of the sound level difference between two rooms. DnT,w is typically used to measure the on-site sound insulation performance of a building element such as a wall, floor or ceiling C tr A sound insulation adjustment, commonly used with Rw and D nt,w. C tr adjusts for low frequency noise, like noise from trucks and subwoofers. C tr values typically range from about -4 to about -12. This term is used to provide information about the acoustic performance at different frequencies, as part of a single number rating system. Page 18 of 21

19 APPENDIX B NOISE MEASUREMENT LOCATIONS MP1 MP3 MP4 MP2 MP5 MP6 Figure B1: Measurement positions 28/06/12. Page 19 of 21

20 APPENDIX C MEASURED NOISE LEVELS Measurement Position and GPS Location Measured Noise Levels (dba) L 10 L eq L 95 Main Noise Sources MP 1 MP 2 MP 3 MP 4 MP 5 MP 6 E N E N E N E N E N E N Alexander Road traffic Alexander Road traffic Alexander Road traffic, some condenser fan noise Alexander Road traffic Alexander Road traffic Alexander Road traffic. The following lists the key details of the noise survey: Date & time: 28 th June :00 13:30. Personnel: Bill Wood, Marshall Day Acoustics Instrumentation: Brüel & Kjær Type 1 Hand Held Analyser Type 2250, serial calibrated 27/06/11 Brüel & Kjær Type 4231 Calibrator, serial , calibrated 14/02/12 Calibration: The analyser was calibrated before measurements, and the calibration checked after measurements. No significant change (±0.1 db) was noted. Microphone height above ground: 1.3 to 1.4 m Weather: Fine, overcast 3/8; temperature 11ᵒC; windspeed 1 to 3 m/s; southwest wind direction. Page 20 of 21

21 APPENDIX D NOISE CONTOURS: CUMULATIVE BUSINESS INDUSTRIAL AND TRAFFIC Figure D1: Example of the effects of combining noise sources. This example shows 5m high barrier, OGPA on Alexander Road and barriers as discussed. Page 21 of 21