3 September 2012

HydroxNominees

c/o Urbis

Level 12 120 Collins Street

MelbourneVic 3000

Attention: Ms Sarah Eamons

Dear Ms Eamons

Masters Corio

It is proposed to develop a Masters Home Improvement Centre and associated shops at a site on Bacchus Marsh Road, Corio. The development site is adjacent to land which may be used for residential purposes in the future. Existing residents are located approximately 175m from the development site.

A noise impact assessment report for the development has previously been prepared by SLR Consulting Australia Pty Ltd. The assessment has shown that activities associated with deliveries are the main noise sources and the assessment is based on a number of worst-case assumptions regarding delivery volumes. It is generally standard practice to assume worst-case scenarios when performing these types of noise assessments.

Since the preparation of the SLR noise impact assessment, a number of Masters stores have been constructed and are now operational and actual delivery volume data is now available. In addition, deliveries will no longer occur during the night-time period.

Marshall Day Acoustics Pty Ltd has been requested to peer review the SLR report and to consider the effect of the revised delivery volume schedule to determine if proposed acoustic treatments can be revised.

Acoustic terms used within this report are provided in Appendix A.

site description

The proposed development will include a Masters Home Improvement Centre and several smaller tenancies. The subject site is bounded by the following:

  • The Geelong Ring Road to the north with farmland across this road
  • Vacant land to the east with existing residential dwellings approximately 175m further east
  • Vacant land to the south
  • Bacchus Marsh Road and industrially developed land to the west.

A site plan is shown in Figure 1.

Figure1: Site plan and surrounds (Source: LefflerSimes Architects)

SLR Assessment

Nearest noise sensitive areas

The noise assessment performed by SLR has identified the nearest residential locations as follows:

  • Existing dwellings approximately 175m to the east of the site
  • Potential future dwellings approximately 10m to the east of the site

Noise limits

SLR has determined the applicable noise limits that would apply to deliveries, waste collections and mechanical plant based on the relevant zoning levels and background noise levels in the area. The day and evening noise limits are provided in Table 1. The night-time noise limits are no longer relevant as deliveries will not occur during the night-time period.

Table1: Noise limits

Period / Day of week / Time period / Noise limit, Leff dB
Day / Monday-Friday / 0700-1800hrs / 54
Saturday / 0700-1300hrs
Evening / Monday-Friday / 1800-2200hrs / 48
Saturday / 1300-2200hrs
Sunday / 0700-2200hrs
Night / Monday-Sunday / 2200-0700hrs / -

Noise predictions

Predictions performed by SLR assumed the following volumes and types of truck deliveries per half hour:

Daytime period

  • 4 semi trailers to the Masters store
  • 4 delivery trucks to the smaller tenancies

Evening

  • 2 semi trailers to the Masters store

This is considered to represent a worse-case scenario. During the planning stage it is typical to use a worst-case scenario for noise modelling where more accurate delivery data is unavailable.

Since the preparation of the SLR assessment, a number of Masters stores have been completed and are operational, allowing for more accurate truck type and volume data to be obtained.

We have been advised that on average, there are 150 deliveries per week on Mondays-Fridays with only 1-2 deliveries on a Saturday to Masters stores. 90% of deliveries are made by 1-5 tonne vehicles and most deliveries occur between 0700-1600hrs.

Based on this information, the following daily truck breakdown is typical for Masters stores:

  • B doubles1
  • Articulated (19m) or large rigid2
  • General purpose (1-5 tonnes) 27

The smaller tenancies are likely to have 1-2 general purpose deliveries per day which are anticipated to occur between 0700-1600hrs.

Based on this data, the typical day and evening half hour delivery schedules have been revised as follows:

Daytime period

  • 1 semi trailer to the Masters store or 2 general purpose deliveries
  • 1 general purpose to the smaller tenancies

Evening

  • 1 general purpose to the Masters store

Noise level data

The noise level data used by SLR for predicting noise emissions includes noise from levels of semi trailers and noise levels of unloading activity which includes forklift use. The sound power levels used by SLR in their predictions for these sources are the same as those used by MDA.

Noise from general purpose trucks are much lower in level and the associated unloading of such trucks – generally performed by hand trolley or scissor lift is also quieter than unloading of a semi trailer which includes forklift use.

Table 2 details the sound power levels of semi trailers, general purpose trucks and the different types of unloading activity.

Table2: Sound power level of delivery vehicles, LAeq dB

Description / SWL
Semi-trailers / 106
General purpose deliveries
1- 5 tonne / 93
Loading bay activity with forklifts / 95
Loading bay with scissor lift/hand trolley / 80

The noise level of general purpose trucks is 13dB lower than a semi- trailer and the noise level of unloading general purpose deliveries is 15dB lower than unloading a semi trailer.

Revised noise predictions

Based on the revised truck volumes, truck types and unloading procedures anticipated at site, the original noise levels predicted by SLR will be significantly reduced.

It is now predicted that the relevant noise limits will be achieved at the existing residential dwellings located 175m to the east of the sitewithout any additional noise control treatments.

Noise emissions within the undeveloped residential land to the east and south may exceed the relevant noise limits by up to 8dB depending on the proximity to the loading areas.

We understand that it is proposed to install a 3m high fence along the eastern boundary of the subject site. This will provide significant shielding and if future residential dwellings to the east and south were single storey, it is likely that the relevant noise limits will be achieved.

If future dwellings are two storey, the ability to achieve the noise limits will be dependent on the actual location of these dwellings, their orientation, the location of balconies and windows.

It is recommended that once the Masters store and associated specialty shops are fully operational and the 3m high barrier is constructed, then noise surveys of actual activities be performed at site. In addition, traffic data should be recorded to confirm that the truck volume assumptions are correct.

The survey results will enable confirmation of compliance with the noise limits at the nearest residential dwellings and also assist in determining the impact on future residential dwellings to the east and south of the subject site.

Once design details of the residential land are known, additional noise control treatmentsmay be required. In relation to designing appropriate noise control measures to protect future housing, the actual requirements will be dependent on the location, orientation, spatial layout and heights (single or double storey) of any future dwellings.

We understand that the developer of the residential dwellings has undertaken to incorporate any additional noise control treatments that may be required through the use of appropriate design response and this will be resolved through the future subdivision and development application for the adjoining residential landholding.

Acoustic Fence Specification

Noise barriers will provide adequate noise attenuation if they have a surface density of
10-15kg/m2 and are free of holes or gaps. Some suitable materials include 25mm thick timber, 18mm thick Perspex, 8mm thick fibre-cement sheet, 75mm thick HebelPowerpanel, concrete, brick or any other approved material that meets the weight specification can be used.

If required, the top portion of the fence may be constructed from a transparent material such as 18mm Perspex if overshadowing is considered to be a potential problem.

The acoustic fence must be free of gaps and penetrations and it is particularly important to ensure that there are no gaps at the bottom of the noise barrier. It is common practice to require that a portion of the bottom of the barrier (say 10-20cm) be buried in the ground.

Council comments relating to the loading dock

The following is an extract from the Council comments relating to the development:

The delivery dock does not need to be enclosed if the relevant SEPP N-1 limits can be achieved.

Based on the discussion above, any additional noise mitigation measures required to meet SEPPN1 can be resolved through the post development acoustic testing and residential permit application process.

We trust this information is satisfactory for your requirements.

Yours faithfully

MARSHALL DAY ACOUSTICS PTY LTD

Elizabeth Hui

Associate

APPENDIXAacoustic 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Pa i.e. dB = 20 x log(P/Pr)
dBA / 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.
LA90 / The A-weighted noise level equalled or exceeded for 90% of the measurement period. This is commonly referred to as the background noise level.
LAeq / The equivalent continuous (time-averaged) A-weighted sound level. This is commonly referred to as the average noise level.
Leff / The effective noise level of commercial or industrial noise determined in accordance with State Environment Protection Policy (Control of Noise from Commerce, Industry and Trade) No. N-1 (SEPP N-1). This is the LAeq noise level over a half-hour period, adjusted for the character of the noise. Adjustments are made for tonality, intermittency and impulsiveness.
SWL or LW / Sound Power Level
A logarithmic ratio of the acoustic power output of a source relative to 10-12 watts and expressed in decibels. Sound power level is calculated from measured sound pressure levels and represents the level of total sound power radiated by a sound source.
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