7. Mitigation and management

7.1 Training

All staff will participate in an induction training session when they commence the Normanby Road early works. The induction will include a briefing on this CNV DWP, with attention given to the following matters:

• Roles and responsibilities for management of noise and vibration • Construction noise and vibration limits • Information about noise and vibration sources on-site • Noise and vibration mitigation and management procedures • The sensitivity of receivers to noise and vibration (including MediaWorks), and any operational requirements and constraints identified through communication and consultation • Complaints management procedures Awareness of current noise and vibration matters on, or near active worksites, will be addressed during site meetings and/or ‘toolbox’ training sessions.

7.2 Construction Hours

Activity

General hours

The Project (MediaWorks) Sensitive Times

Days

Monday to Saturday:

Sunday: All other times (night)

Monday to Friday

Times

0700 –1900 hrs 1900 –2200 hrs 0700 –2200 hrs 2200 –0700 hrs

1600 –20:00 hrs

Condition: Comment

31: Prioritise. 31: Minimise where practicable. 31: Minimise where practicable. 31: Avoid where practicable.

Refer SSCNVMP in Appendix C24

Piling and road cutting Monday to Saturday 0700 –1900 hrs 36.3 b): Restricted period.

7.3 Mechanical Plant Selection

Some activities have the potential to exceed the Project Standards forconstruction noise and vibration at close receiver distances. It is essential that appropriate mitigation and management measures are identified and employed in advance of the works to avoid exceedances. When selecting construction equipment:

Equipment will be suitably sized for the proposed task

Equipment will be well maintained

Exhaust silencers will be fitted

Fit or upgrade engine covers in consultation with equipment manufacturer where appropriate

Substitute diesel engines with electric motors where practicable

7.4 General Mitigation Measures

Best Practical Option (BPO) mitigation will be implemented throughout the construction programme to avoid exceedances. This will include, but not be limited to the following: Page 23 | Normanby Road Early Works

Keep the construction time near noise sensitive areas to a minimum Avoid unnecessary noise, such as shouting, the use of horns, loud site radios, rough handling of material and equipment, and banging or shaking excavator buckets

Avoid metal on metal contact where practicable by minimising drop height of materials, such as during loading and unloading of trucks

Tonal reversing alarms shall be prohibited on site. Suitable alternatives may include flashing lights, broadband audible alarms or reversing cameras inside vehicles Mitigate track squeal from tracked equipment, such as excavators and piling rigs. This may include tensioning and watering or lubricating the tracks regularly

Avoid high engine revs where practicable through appropriate equipment selection and turn engines off when idle / parked Avoid steep internal haul routes and keep the road surface smooth and well maintained Maximise the distance between the noise source and the nearest sensitive receiver by positioning fixed plant away from sensitive receivers, or orienting machinery to maximise the distance between the engine exhaust and the nearest sensitive building façade where practicable (e.g. bored piling rig, excavators and mobile cranes)

Crane and secure loads using straps in preference to chains where safe and practicable;

Utilise power from the national grid in preference to generators where practicable

Utilise noise barriers and enclosures where effective (Section 7.5)

Implement further measures identified through communication and consultation with sensitive receivers (Section 8) Undertake noise and vibration monitoring to confirm compliance or identify high noise and/or vibration machinery (Section 9)

7.5 Noise Barriers and Enclosures

Site boundary fences will be constructed, or existing fences upgraded, to provide effective noise mitigation during construction. Temporary noise barriers will be used where a construction noise limit is predicted to be exceeded (Section 6.1) and the barriers would noticeably reduce the construction noise level. Noise barriers will be installed prior to works commencing and be maintained throughout the works. Effective noise barriers typically reduce the received noise level by 10 decibels. Where practicable, the following guidelines will be incorporated in the design and utilisation of noise barriers:

The panels will be constructed from materials with a minimum surface mass of 6.5 kg/m2, including the following proprietary ‘noise curtains’: - Duraflex ‘Noise Control Barrier - Premium Series’ (www.duraflex.co.nz) - Soundex ‘Acoustic Curtain - Performance Series' (www.ultimate-solutions.co.nz) - Flexshield ‘Sonic Curtain with 4 kg/m2 mass loaded vinyl backing’ (www.flexshield.co.nz) - Alternatives will be approved by a suitably qualified acoustic specialist because some proprietary noise curtains have insufficient surface mass for general use

The panels will be a minimum height of 2m, and higher if practicable to block line-of-sight;

The panels will be abutted or overlapped to provide a continuous screen without gaps at the bottom or sides of the panels;

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• The panels will be positioned as close as practicable to the noisy construction activity to block line-of-sight between the activity and noise sensitive receivers; and • Where positioned on the site boundary, additional local barriers will be considered near the activity to ensure effective mitigation for sensitive receivers on upper floor levels. Noise enclosures surround the sound source with noise barriers on more than one side and include a ‘roof’. The effectiveness of noise enclosures depends on the extent that the source can be enclosed without constraining the operation of the equipment and resulting in an unacceptable occupational health and safety environment (e.g. noise exposure, heat, dust, poor lighting etc). Enclosures can also result in traffic management issues and increase construction duration for short term or transient activities.

The following guidelines will be incorporated in the design and utilisation of noise enclosures where practicable and effective:

Enclosures will be used for stationary plant where a noise barrier is not sufficient to achieve compliance with the noise limits and it is practicable to do so (e.g. fixed paver cutting stations, pumps, concrete crushing plant, spoil handling conveying equipment etc).

The enclosure can be erected using the noise curtains listed above, or alternatively, the following proprietary cutting station ‘noise enclosures’ can be used: − Echo Barrier ‘Cutting Station’ (www.supplyforce.co.nz ) − Soundex ‘E6/2 Quick-Tech Cutting Enclosure' (www.ultimate-solutions.co.nz) − Hushtec ‘Acoustic Tent’ (www.duraflex.co.nz) Alternatively, a suitably qualified and experienced acoustic specialist (such as MASNZ) will be involved in the custom design of the enclosure (an example is included as Figure B.3 in NZS 6803:1999). An onsite assessment should be undertaken at potential enclosure locations as to whether an enclosure is able to be installed safely.

7.6 Concrete and Paver Cutting

Where practicable: • Use noise barriers for concrete cutting and a noise enclosure for paver cutting stations (Section 7.5) • Minimise the concrete cutting period, and, the number of cutting periods (e.g. complete all cutting in one extended period rather than two shorter periods with the same overall duration) • Select blades that are sharp, maximise the number of teeth, minimise the blade width, minimise gullet depth, and have built in vibration damping slots • Use a unit fitted with a blade shroud and operate with a water supply

7.7 Concrete and Rock Breaking

Avoid MediaWorks broadcast ‘Sensitive Times’ for breaking within 100m of The Project building at 71 Boston Road, unless monitoring verifies compliance with the limits in designation Condition 35.2 (Appendix C24. Other general measures include the following where practicable: • Use local noise barriers to screen the breaker tip (Section 7.5)

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For concrete breaking near buildings, an initial perimeter saw cut will be made at the perimeter to reduce vibration transfer

For rock breaking, initial breaking will be undertaken at the perimeter of the rock face closest to neighbouring buildings. This will enable monitoring of the highest vibration levels received at nearby buildings for compliance purposes (Section 9.2). It will also mitigate the vibration transfer from subsequent breaking by creating a ‘trench’ of fractured rock between the breaker and nearby buildings. Minimise the volume of breaking (e.g. use a crushing shear or pulveriser attachment in place of a breaker, or use a cut and lift approach to enable breaking in the centre of site)

Minimise the duration of breaking, and the number of breaking periods (e.g. complete all breaking in one extended period rather than two shorter periods with the same overall duration)

Match the size of breaker to the scale of the works (i.e. large enough to undertake the works efficiently, but avoiding oversized units)

Match the chisel/tip type to the material and use a dampened bit to avoid ringing; and

Avoid ‘blank’ firing by engaging the material before commencing and stopping before it fires through the material.

7.8 Piling

Where practicable: • Prioritise piling methods that minimise noise and vibration (e.g. augured, screw or press-in piles over impact driven or vibratory piling methods) • Minimise alternating rotation of the bored piling auger to loosen spoil into the muck bin. Shaking the ‘kelly bit’ connection creates very loud banging that can result in noise complaints. It is understood this action can be avoided for general auger use but is necessary specifically when a coring barrel is used to drill through obstructions (due to Health and Safety issues related to alternative ways of loosening material from the bit).

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