MELBOURNE METRO RAIL PROJECT Construction: noise Operation: noise and vibration Dave Anderson 1
Outline • Peer Review – Summary of noise and vibration assessment – Environmental Performance Requirements – Findings and recommendations from review • Submissions, conclave – Key issues – Recommendations • Conclusions 2
Peer Review: Purpose and Scope • Purpose – Assess the Noise and Vibration Impact Assessment (NVIA) – Identify issues for consideration prior to the NVIA being finalised – Provide recommendations for further consideration through the EES process • Scope – Noise and vibration standards and criteria – Noise and vibration prediction methodologies and results – Proposed noise and vibration mitigation and the assessment of residual impacts 3
Peer Review: Methodology • Desktop review – Review and comment on draft versions of NVIA – Review proposed Environmental Performance Requirements (EPRs) • Meetings / discussions with AJMJV – Ground borne noise and vibration from excavation and construction ( refer to Dr John Heilig’s evidence ) – Ground borne noise and vibration from future rail operations throughout the project area 4
Peer Review: Findings • Appropriate criteria • Competent modelling • Appropriate detail for – the scale of the project – the stage of the assessment • Comments addressed – Description and mitigation of daytime construction noise – Construction noise barrier heights – Framework for temporary relocation 5
Peer Review: Recommendations • Describe construction noise impacts and mitigation fully, even where numerical noise criteria are not prescribed by the EPA Guidelines (e.g. for Daytime and Unavoidable works) • Clearly define procedures for respite and temporary relocation during construction • Demonstrate feasibility of attenuating noise from fixed plant 6
Construction noise impacts • Overview / context • Concept approach demonstrates – Initial demolition & excavation • Daytime only • Standard mitigation techniques • High noise levels at nearest affected receivers – Long term 24/7 works • Underground / enclosed, therefore much lower noise levels – Short term 24/7 works • Additional mitigation framework 7
Noise from Construction Vehicles • Operational procedures recommended for trucks (refer new EPR NVB item 18) – Limit to daytime hours where possible – Avoid local / residential streets where practical – Appropriate noise control (no engine braking, compliant mufflers, maintain road surfaces, use broadband reverse alarms) – Avoid idling near sensitive receivers, where practical 8
Respite and Relocation • Working draft Residential Impact Management Guidelines for Construction (RIMG). • Framework for determining eligibility for “off-site” mitigation of airborne noise, including – acoustic treatment – alternative accommodation 9
Attenuation of Noise from Fixed Plant • The NVIA noted that “Plant noise is expected to be able to be mitigated to comply with the noise limits….” • I requested clarification to confirm the practicality of noise attenuation, particularly for cooling plant (such as chillers, condensers etc) • Technical Note 54 provides an example, based on an indicative chiller plant location in the Domain precinct, which demonstrates that noise attenuation is practical 10
Submissions / Conclave • Key issues – Construction stage • Noise predictions and assessment • Noise criteria, mitigation, management and monitoring • Noise from construction vehicles – Operational stage • Rail noise and vibration impacts • Ongoing maintenance to ensure compliance • Fixed plant noise affecting non-residential receivers 11
Construction Noise Predictions • Predictions assumed all plant operating for 100% of the assessment period (appropriately conservative) • However, some assumed noise source levels were relatively low, for example: – Trucks (modelled for idling only) – Diaphragm wall rig (91dBA vs 105dBA) • The range of plant and equipment modelled on each site means predictions are not highly sensitive to the assumptions on specific plant 12
Construction Noise Predictions • I have checked and confirmed that that this does not make a significant difference to the overall noise level predictions. • For example: – Diaphragm wall rig (91) + piling rig (111) = 111 – Diaphragm wall rig (105) + piling rig (111) = 112 13
Construction Noise Predictions • Predictions affecting high-rise receivers: – Ignore benefit of hoardings and barriers – Include reflections from other hi-rise buildings • In conclusion, the airborne noise levels shown in the EES are representative 14
Construction Noise Criteria • Construction is an inherently noisy activity and, in my experience, the key requirement is to ensure practical mitigation and management. • EPA 480 (ref EPR EM2) requires “All noise nuisance to be reduced wherever possible” and EPA 1254 (ref EPR NV1) requires “reasonable measures to reduce impact” (and so on). • The EPA guidelines also require noise management, monitoring and independent review. • The draft RIMG provides a framework for respite and relocation to address night-time impacts affecting residents 15
Construction Noise Criteria • A number of submissions and expert witnesses recommend numerical noise criteria for daytime and Unavoidable Works • This approach has been used for large infrastructure projects in NSW and overseas • To my knowledge, it has not been used for large infrastructure projects in Victoria • Arguments for adopting criteria include: – An objective basis to predict the need for additional mitigation in advance – A more transparent method to demonstrate and audit whether practical means to reduce noise have been applied • Refer conclave report (Document 63), items 06 and 10 16
Operational Airborne Noise Impacts • Airborne noise impacts occur in areas with existing rail noise • Victorian Passenger Rail Infrastructure Noise Policy applied • Concept design demonstrates mitigation to address predicted exceedances – Note error in reference to Tables C4 and C6 – Text refers “noise level exceedance” but table actually shows “predicted increase” • Refer conclave report (Document 63), item 20 17
Ground Borne Noise and Vibration • The criteria are based on those used in NSW and considered suitable • The NSW ground borne noise criteria “are necessarily set to the lower end of the range of possible trigger values so that potential impacts on quieter suburban locations are addressed. In practice, higher levels of ground-borne noise than the trigger level for assessing impacts may be appropriate for urban areas where background noise levels are relatively high.” 18
Ground Borne Noise and Vibration • Prediction methodology appropriate • Complexity and uncertainty recognised • Ground propagation studies required at detailed design as well as sensible contingency • Mitigation proposals reasonable • Refer conclave report (Document 63), items 15, 18, 19, 22, 23 19
Conclusions • Peer review findings • Construction noise • Operational noise and vibration • Issues from submissions and EWSs – Criteria – Management Plan – Independent Review • Recommendations and EPRs arising 20
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