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Sound1.01 and Environmental Noise Presented to the Young RMLA by Siiri Wilkening.

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Presentation on theme: "Sound1.01 and Environmental Noise Presented to the Young RMLA by Siiri Wilkening."— Presentation transcript:

1 Sound1.01 and Environmental Noise Presented to the Young RMLA by Siiri Wilkening

2 2 On the menu Sound 1.01 NZ NoiseStandards Road Traffic Noise Construction Noise

3 3 Physics of sound Sound is a pressure fluctuation, travelling in waves Valve rotation = 100 /sec Frequency of Sound = 100 Hz Loudspeaker Sound can vary in frequency (pitch) and level (magnitude)

4 4 Frequency & wavelength Frequency & wavelength of everyday sound

5 5 Frequency weighting A weighting: Response of the human ear Commonly used for industrial and environmental noise assessment

6 6 Sound Level – The decibel (dB) scale Pressure Scale is Impractical Decibel scale chosen for convenience Hearing response is logarithmic rather than linear Lawnmower (85 dB) + Lawnmower (85 dB) = 88 dB Typical sound pressure levels

7 Changes in Noise Level Negligible/less than minor Slight/Minor Moderate Significant/Substantial Serious/Severe Impact / RMA Effect Subjective Reaction Insignificant change Perceptible change Appreciable change Halving/doubling of loudness More than a halving/doubling of loudness Change in Sound Level (dB) 1 - 2 3 - 4 5 - 8 9 - 11 > 11

8 8 Statistical Analysis L Amax L A10 L Aeq L A90 L Amax maximum noise level L A10 level exceeded for 10% of the time L Aeq average noise level L A90 level exceeded for 90% of the time

9 Common Misconceptions Trees act as an acoustic barrier – No! Need at least 100m of dense bush for 3 dB reduction Putting eggboxes on the walls of my band room means I can play as loud as I like No! Too light to insulate against noise. Sound travels upwards No! Sound travels in all directions.

10 Overview of NZS 68xx Series 6801: Measurement & Definitions 6802: Assessment (General Sources) 6803: Construction Noise 6805: Airport Noise 6806: Road Traffic Noise 6807: Helicopter Noise 6808: Wind Turbine Noise 6809: Port Noise

11 11 NZS 6806:2010 Acoustics – Road-traffic noise – New and altered road

12 12 Basic Considerations Virtually everyone contributes and is affected Not entirely controllable Flexibility and pragmatism Based on RMA, specifically BPO

13 13 Limitations Applies only if project has (some) adverse effect Minimum performance for mitigation Defined assessment area (100/200 m from road) Maintenance excluded (e.g. resurfacing)

14 14 Noise Criteria Categories

15 15 Criteria (all L Aeq(24h) ) Category A - Primary, external 57 dB new roads / 64 dB altered roads Category B – Secondary, external 64 dB new roads / 67 dB altered roads Category C – Backstop, internal 40 dB (if internal level would be 45 dB or more)

16 16 Mitigation Options Structural Mitigation: Road surface Barriers or bunds (or tunnels) Building Modification Mitigation Ventilation Insulation

17 17 Noise Barriers Effectiveness: length and height Close to source or receiver Break acoustic line-of-sight Barrier material 10 -15 kg/m 2 17 mm ply 9 mm fibre cement 20 mm timber board and batten

18 18 NZS 6806: BPO Assessment Iterative process Input from entire Project Team Advantage: robust and practicable mitigation Implications: Time!!! and potential confusion

19 19 Main Issues Criteria: Category C (internal) perceived better than Categories A and B (external) Uncertainty: no definitive limit (Note: condition formulation) Inclusion of cost: Its a dirty word!

20 20 NZS 6803:1999 Acoustics- Construction Noise

21 21 Basic Considerations Construction activities are: Noisier than normal activities Of limited/finite duration Necessary to progress society Need to find balance between Amenity of residents/affected parties Necessity of works

22 22 Recommended Criteria Residential: Day 75 dB L Aeq / 90 dB L Amax Night 45 dB L Aeq / 75 dB L Amax Business: Day 75 dB L Aeq Night 80 dB L Aeq Can be adjusted for Duration Ambient noise levels

23 23 Construction Noise Management Construction Noise and Vibration Management Plan CNVMP Site Specific Construction Noise/Vibration Management Plans SSCNMPs/SSCVMPs

24 24 Construction Mitigation Monitoring Temporary/permanent barriers Shielding of individual items of equipment Selection of equipment

25 25 Construction Mitigation - continued Noise sensitive activities, e.g. schools, hospitals: timing Consultation/Communication Miscellaneous: reversing alarms, unsecured tail gates, radios, horns, shouting

26 26

27 27 Offices Auckland (20) Wellington (5) New Plymouth (1) Christchurch (5) Hamilton (1) Melbourne (24) Sydney (4) Adelaide (2) Perth (2) Shanghai (2) Hong Kong (1) Ireland (2) Great Britain (2) France (1)

28 28 2013 Group Conference

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