vipac engineers & scientists westfield design ... · melbourne sydney adelaide perth brisbane...

Melbourne Sydney Adelaide Perth Brisbane Hunter Valley Tasmania Singapore Hong Kong Dubai

Vipac Engineers & Scientists Ltd.

2 Sirius Road, Lane Cove, NSW 2066, Australia

t. +61 2 9422 4222 | f. +61 2 9420 5911 | e. [email protected]

w. www.vipac.com.au | A.B.N. 33 005 453 627 | A.C.N. 005 453 627

Vipac Engineers & Scientists

Westfield Design & Construction Pty Ltd

Westfield Knox - Acoustics

Report

20E-13-0181-DRP-340053-16

2 April 2014



Report

2 April 2014

20E-13-0181-DRP-340053-16 Commercial-In-Confidence of 12

Report Title: ReportJob Title: Westfield Knox - Acoustics

DOCUMENT NO: 20E-13-0181-DRP-340053-16 REPORT CODE: DRP

PREPARED FOR: PREPARED BY:Westfield Design & Construction Pty Ltd Vipac Engineers & Scientists Ltd.

85 Castlereagh Street 2 Sirius Road,

Sydney NSW 2000 Lane Cove, NSW 2066,

GPO Box 4004 Sydney NSW 2001 Australia

CONTACT: Scott Marston

Tel: +61 2 9358 7000 Tel: +61 2 9422 4222

Fax: +61 2 9028 8500 Fax: +61 2 9420 5911

PREPARED BY:

Author: Date: 2 April 2014

Lucinda Bowden

Project Engineer

REVIEWED BY:

Reviewer: Date: 2 April 2014

Xun Li

Senior Acoustic Consultant

AUTHORISED BY:

Date: 2 April 2014

Lucinda Bowden

Project Engineer

REVISION HISTORY

Revision No. Date Issued Reason/Comments

0 25 Oct 2013 Initial Issue

11 16 Dec 2013 Clients Comments

14 17 Mar 2014 Council Comments

16 2 April 2014 Updated Plans

DISTRIBUTION

Copy No.______ Location

1

KEYWORDS:

NOTE: This is a controlled document within the document control system. If revised, it must be marked SUPERSEDED and returned to the Vipac QA Representative. This document contains commercial, conceptual and engineering information that is proprietary to Vipac Engineers & Scientists Ltd. We specifically state that inclusion of this information does not grant the Client any license to use the information without Vipac’s written permission. We further require that the information not be divulged to a third party without our written consent.



Report

2 April 2014


TABLE OF CONTENTS

INTRODUCTION ..............................................................................................................................41

1.1 Drawings ...........................................................................................................................................5

ASSESSMENT CRITERIA...............................................................................................................52

SITE DESCRIPTION ........................................................................................................................63

SITE MEASUREMENTS ..................................................................................................................74

4.1 Noise measurements........................................................................................................................7

4.2 Instrumentation .................................................................................................................................7

4.3 Measurement results ........................................................................................................................7

ASSESSMENT .................................................................................................................................85

5.1 Carpark noise in community .............................................................................................................8

5.2 New Loading Bay..............................................................................................................................9

5.3 New plant equipment ..................................................................................................................... 10

CONCLUSION............................................................................................................................... 116

INSTRUMENTATION ..................................................................................................... 12APPENDIX A:



Report

2 April 2014


INTRODUCTION1

Vipac Engineers & Scientists were engaged by Westfield Design & Construction Pty Ltd to undertake a noiseassessment of the expansion to the Westfield Knox shopping centre at Wantirna South, Victoria. The expansion is to include an additional leasable area of approximately 46,000m2, existing car spaces will increase from approximately 6,200 spaces to 8,900 and a total of 8 new plant rooms are proposed.

Westfield Design & Construction Pty Ltd engaged Vipac to establish the noise emissions of the expansion and the impact this will have on the nearest residential properties. In the expansion the potential noise sources that may impact the nearest residential property are the new North West car parking facilities and the new loading bay and roof top plant servicing the mini major to the North of the shopping centre.

The assessment includes onsite measurements and noise prediction calculations.

This report has been updated in response to Council’s letter dated 14 January 2014 which requested the following:

Acoustic

19. An assessment of the predicted noise levels of the Level 1, Level 1M, level 2M, level 3 and Level 3m car parks closest to the residential properties, the new access way along the northern boundary and any new loading bay/s in proximity to the northern properties, including any recommendations to reduce noise to the levels specified in the Vipac Acoustic report.

20. Clarification on the conclusion drawn on Page 10 of 11 in the Vipac Acoustic report ‘that the new roof top plant servicing the new mini-major will not increase the existing noise levels at the residential area”, while at Section 5.3 the report states that “further recommendations can only be confirmed upon review of equipment schedules, operating conditions and services design drawings”. The new plant appears to be closer to residential areas.

Figure 1: Site layout with Expansion



Report

2 April 2014


1.1 Drawings

This report is based on the updated plan drawings (1st April 2014) from Westfield Design & Construction Pty Ltd listed in Table 1.1.

Table 1.1: List of drawings

Drawing description Drawing Number Received

North East Elevation DA05.0010A April 2014

Stage 1 – Level 1 Retail Plan DA05.0002A April 2014

Stage 1 – Level 1M Carpark Plan DA05.0003A April 2014

Stage 1 – Level 2 Retail Plan DA05.0004A April 2014


Stage 1 – Level 3 Carpark Plan DA05.0006A April 2014


Stage 1 – Roof Plan DA05.0008A April 2014

Section A - C Car park Screens DA05.0014A April 2014

ASSESSMENT CRITERIA2

Expansion of Car Parks

In general, two indoor noise criteria for a sleeping area in a residential property LAeq and LAmax can be considered for a night period (10pm – 7am). In this project the LAmax which is appropriate for measuring the sleeping disturbance for a single noise event (short period) is adopted rather than LAeq (Equivalent Continuous A-Weighted Sound Level). The reason for using this criteria strategy is the noise causing annoyance in a car-park is caused more by a single event such as a car starting, accelerating on a ramp and a car door slamming. Therefore the single event measure of LAmax is more suitable for assessing car-park noise impact to the sleeping areas in the residential properties.

The indoor noise criteria strategy from the VCAT Red Dot Decision Summary –The tribunal, Pomeroy Pacific Pty Ltd v Moreland CC No.2 2011 VCAT 475 is used for the current project. The noise report used in tribunal gave two options to achieve either a 55dBA Lmax or less or a 60DBA Lmax or less. The council requested the 55dBA Lmax or less option. The tribunal applied 55dBA Lmax or less for the bedrooms and 60dBA Lmax or less for the living areas.

The assessment of the expansion at Westfield Knox shopping centre will use the following criteria:

LAmax noise levels are not to exceed 55 dBA in bedroom areas and 60 dBA in living room areas.

Note: The EPA environmental noise regulation (SEPP N-1) in Victoria does not cover car park noise.

Additional Loading Bays

The expansion of Westfield Knox shopping centre will include new loading bays. Vipac's assessment will look solely at new loading bays that may impact neighbouring residential properties. The new loading bays will be assessed to ensure no increase of existing noise levels at the nearest residential properties.

Additional Roof Plant

The expansion of Westfield Knox shopping centre will include new roof top plant. Vipac’s assessment will look solely at new roof top that may impact neighbouring residential properties. The new roof plant equipment will be assessed to ensure no increase of existing noise levels at the nearest residential properties.



Report

2 April 2014


Traffic Increase

It’s noted that the traffic volume will increase due to the expansion. However the noise impact from the increase of traffic volume is negligible on the residential properties in the evening period as the shopping centre closes at the latest 9:00pm. Once the shopping centre is closed there will be no expected traffic flow during the night period.

SITE DESCRIPTION3

Westfield Knox Shopping Centre is located at 425 Burwood Highway, Wantirna South, Victoria. To the North -North East is residential area, to the East – South East is industrial area, to the South West runs Burwood highway, to the North to North West is residential area.

In terms of noise impact from the expansion of Westfield Knox in the community, the residential properties potentially affected by the expansion are located North of Westfield Knox.

Figure 2: Site Location



Report

2 April 2014


SITE MEASUREMENTS4

In the expansion the noise sources that may impact the nearest residential properties (shown in Figure 2) are the new North West car parking facilities and the new loading bay area and roof top plant servicing the mini major to the North of the shopping centre. The nearest residential property (residents at Gateshead Drive) is located 20 meters North East of Westfield Knox Shopping Centre which will be used in our assessment as worst case.

To assess the noise emissions Vipac made onsite measurements of noise levels in the current underground car park. Vipac used the existing and proposed operating hours of the loading bay to ensure no increase of existing noise levels at the nearest residential property. Vipac used the location of existing and new roof top plant to ensure no increase of existing noise levels at the nearest residential property.

4.1 Noise measurements

To identify the existing car park noise levels at Westfield Knox the vehicle noise levels measured in the current undercover (ground floor – North-west) car park between 2:00 – 3:00 pm on the12th Oct 2013. The traffic consultant report for the project shows that this period is peak time for using the car park. The measurements included that of a passenger car, sport cars, 4WD and delivering vans. The main reason for choosing the measurement locations (undercover car park) is the noise levels under a building cover are higher than those in an open space due to the reverberant effect in the building.

4.2 Instrumentation

The instruments used for measurements in this report are calibrated by a NATA certified laboratory. The instruments are listed in Appendix A.

The measurement instruments were regularly checked for calibration during the measurements and no significant drifts were found (<0.1 dB).

4.3 Measurement results

Measurements were made in the current undercover (ground floor – North-west) car park between 2:00 – 3:00 pm on the12th Oct 2013. Measurements of the overall LAmax for duration of 15 minutes are summarized inTable 5.1.

Table 5.1: Vehicle noise measured in the current undercover car park

Location Overall noise level, Lmax,15min, dBA

1 72

2 75

Average 73.5



Report

2 April 2014


ASSESSMENT5

5.1 Carpark noise in community

According to the site layout for the new extensions as shown in Figure 1 new multi-level car parks (Level 1, Level 1M, Level 2, Level 2M and Level 3) are located in the North West of site. It is noted that the existing carparks (Ground level and Level 1) in the North East of the site are extended to Level 3M.

According to the proposed façade constructions (drawing: Section A - C Car park Screens) the similar acoustic properties of car park façades (1300 mm concrete barriers + perforated acoustic panels) are proposed for the new extensions and therefore, the noise from Level 2 car park in the North East of North West extension to the residents at Gateshead Drive was considered as the worst case scenarios for the assessment. This consideration was based on the shortest distance between the car park and residents.

Calculations were used to predict the noise levels with no wind effect due to the short distance between the car park and residents.

The predicted noise levels have been calculated based on the following recommended constructions:

Level 2 car park - 1300mm high concrete crash barrier, with attached full height perforated acoustic corrugated steel on the internal face with green wall screen on the external (Shown in Figure 3).

Figure 3: Level 2 Crash Barrier

The predicted noise levels were calculated for Level 2 of the car park with a perforated barrier. The predicted noise levels at 1 m from the façade (including distance and barrier effect) is to 63 – 65 dBA (LAmax) at the nearest sensitive receivers to the north-west.

The indoor noise criteria given in Section 2 can then be achieved in the residential property by using proper building envelope constructions and the building orientation. General building envelope construction can achieve 20 – 25 dB noise reduction with windows closed or 10 dB noise reduction at a distance with windows open.



Report

2 April 2014


5.2 New Loading Bay

Vipac has been informed that there will be a new loading bay at mini major located to the North of the shopping centre. The new loading bay will be adjacent to existing loading bay C Dock and D Dock shown in Figure 4.

Figure 4: Loading Bays

The operating times of the existing loading bays and the new loading bay dock are shown in Table 5.1. The new loading bay will have the same operating times as the existing loading bay C dock. Vipac anticipates that the new loading bay will not increase the existing noise levels at residential area as its operating hours will be the same as the adjacent existing loading bay and shorter operating times than D Dock.

Table 5.1: Loading Bay Operating Hours

Dock Name Mon - Wed Thu - Fri Sat Sun

New Dock 0630 - 1815 0630 - 2115 0630 - 1715 0730 - 1715

A Dock 0630 - 1815 0630 - 2115 0630 - 1715 0730 - 1715

C Dock 0630 - 1815 0630 - 2115 0630 - 1715 0730 - 1715

D Dock 0515 - 1815 0515 - 2115 0515 - 1715 0630 - 1715

E Dock 0630 - 1815 0630 - 2115 0630 - 1715 0730 - 1715

Loft Dock 0300 - 1815 0300 - 2115 0300 - 1715 0300 - 1715

Brisbane Lane 07:00 - 17:30 07:00 - 21:30 07:00 - 17:30 07:00 - 17:30

Village Dock 06:00 - 18:15 06:00 - 18:15 06:00 - 18:15 06:00 - 18:15

Ozone 0600 - 2330 0600 - 2115 0600 - 2330 0600 - 2330

Toys R Us 0630 - 1815 0630 - 2115 0630 - 1715 0630 - 1715

Myer 07:00 - 17:00 07:00 - 21:00 07:00 - 17:00 07:00 - 17:00

Coles 4:00 - 22:00 4:00 - 22:00 4:00 - 22:00 4:00 - 22:00

New Loading Bay



Report

2 April 2014


5.3 New plant equipment

Vipac has been informed that a new AHUs plant servicing the mini major will be installed on the roof, asshown in Figure 5. Total 4 air handling units (AHUs) are installed in the plant.

Figure 5: New Plant Equipment

The sound power levels for the new plant equipment were provided by the client (Westfield) and summarized below.

Table 5.2 Sound power spectrum of new AHU

Octave band central frequency (Hz) Overall (dBA)63 125 250 500 1000 2000 4000 8000

97 93 95 87 81 76 72 65 90

To assess the noise impact from the new plant on the residents at Gateshead Drive the Zoning Limits for Night period (22:00 – 7:00) at the residents was derived according to the state EPA environmental noise policy (SEPP N-1) and it is 44 dBA. This Zoning Level is implemented as the environmental noise limit (neutral, defined in SEPP N-1) for the assessment for the new plant noise.

The total noise level from the new plant (including 4 AHUs) as shown in Figure 5 is 44 dBA. This noise level just reaches the Zoning Limit of 44 dBA. Therefore, the further reduction on the noise emission from the new plant should be achieved to ensure that no noise impact from the new plant on the residents occurs.

To reduce the noise from the new plant the noise walls around the plant are recommended, as sketched in Figure 6 below. The wall height should be 1 m above the top of plant.

The wall construction is summarized below.

0.42 mm colorbond sheet + 50 mm insulation blanket covered by Melinex facing protection +perforated sheetmetal with 25 % opening area.



Report

2 April 2014


It should be noted that the perforated side of the walls shall face the source (new plant).

Figure 6 Sketch of the noise wall around the new plant

CONCLUSION 6

Vipac Engineers & Scientists were engaged by Westfield Design & Construction Pty Ltd to undertake a noise assessment of the expansion to the Westfield Knox shopping centre at Wantirna South, Victoria. The expansion is to include an additional leasable area of approximately 46,000m2, existing car spaces will increase from approximately 6,200 spaces to 8,900 and a total of 8 new plant rooms are proposed.

Westfield Design & Construction Pty Ltd engaged Vipac to establish the noise emissions of the expansion and the impact this will have on the nearest residential properties. In the expansion the potential noise sources that may impact the nearest residential property are the new North West car parking facilities and the new loading bay and roof top plant servicing the mini major to the North of the shopping centre.

The noise impact from the new car park extensions on the residential properties in the north of the site (Gateshead Drive and pinewood Drive) was assessed in Section 5.1. The assessments demonstrate that the proposed car park façades (1300 mm concrete barriers + perforated acoustic panels) satisfied the requirements for car park noise reductions. (Re Item 19 Knox City Council RFI)

The noise impact from the new loading bay servicing the mini major on the nearest residential property (Gateshead Drive) was assessed. It is concluded that the new loading bay will not increase the existing noise levels at the residential area, as the operating hours will be the same as the existing adjacent loading bay Dock C. (Re Item 19 Knox City Council RFI)

The noise impact from the new roof top plant servicing the mini major on the nearest residential property (Gateshead Drive) was assessed. The noise walls around the plant were recommended in Section 5.3. (Re Item 20 Knox City Council RFI)

1 m

Noise wall

Flush with end of plant



Report

2 April 2014


INSTRUMENTATIONAppendix A:

Instrument MODEL/TYPESERIAL NO.

CALIBRATION DUE

Bruel & Kjaer sound level meter (type 1) 2250 2690200 05 Dec 2013Bruel & Kjaer microphone calibrator 4230 1139057 31 May 2014

vipac engineers & scientists westfield design ... · melbourne sydney adelaide perth brisbane...

Documents