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Sound1.01 and Environmental Noise. Presented to the Young RMLA by Siiri Wilkening. On the menu. Sound 1.01 NZ NoiseStandards Road Traffic Noise Construction Noise. Physics of sound. Sound is a pressure fluctuation, travelling in waves

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sound1 01 and environmental noise

Sound1.01 andEnvironmental Noise

Presented to the Young RMLA by

SiiriWilkening

on the menu
On the menu
  • Sound 1.01
  • NZ NoiseStandards
  • Road Traffic Noise
  • Construction Noise
physics of sound
Physics of sound
  • Sound is a pressure fluctuation, travelling in waves
  • Valve rotation = 100 /secFrequency of Sound = 100 Hz
  • Loudspeaker
  • Sound can vary in frequency (pitch) and level (magnitude)
frequency wavelength
Frequency & wavelength

Frequency & wavelength of everyday sound

frequency weighting
Frequency weighting
  • “A” weighting: Response of the human ear
  • Commonly used for industrial and environmental noise assessment
sound level the decibel db scale
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

changes in noise level
Changes in Noise Level

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

Impact / RMA Effect

Negligible/less than minor

Slight/Minor

Moderate

Significant/Substantial

Serious/Severe

statistical analysis

LAmax

LA10

LAeq

LA90

Statistical Analysis
  • LAmax maximum noise level
  • LA10 level exceeded for 10% of the time
  • LAeq average noise level
  • LA90 level exceeded for 90% of the time
common misconceptions
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.

overview of nzs 68xx series
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
basic considerations
Basic Considerations
  • Virtually everyone contributes and is affected
  • Not entirely controllable
  • Flexibility and pragmatism
  • Based on RMA, specifically BPO
limitations
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)
criteria all l aeq 24h
Criteria (all LAeq(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)
mitigation options
Mitigation Options
  • Structural Mitigation:
    • Road surface
    • Barriers or bunds (or tunnels)
  • Building Modification Mitigation
    • Ventilation
    • Insulation
noise barriers
Noise Barriers
  • Effectiveness: length and height
  • Close to source or receiver
  • Break acoustic line-of-sight
  • Barrier material 10 -15 kg/m2
    • 17 mm ply
    • 9 mm fibre cement
    • 20 mm timber board and batten
nzs 6806 bpo assessment
NZS 6806: BPO Assessment
  • Iterative process
  • Input from entire Project Team
  • Advantage: robust and practicable mitigation
  • Implications: Time!!! and potential confusion
main issues
Main Issues
  • Criteria: Category C (internal) perceived “better” than Categories A and B (external)
  • Uncertainty: no definitive “limit” (Note: condition formulation)
  • Inclusion of cost:It’s a dirty word!
basic considerations1
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
recommended criteria
Recommended Criteria
  • Residential:
    • Day 75 dB LAeq / 90 dB LAmax
    • Night 45 dB LAeq / 75 dB LAmax
  • Business:
    • Day 75 dB LAeq
    • Night 80 dB LAeq
  • Can be adjusted for
    • Duration
    • Ambient noise levels
construction noise management
Construction Noise Management
  • Construction Noise and Vibration Management Plan — CNVMP
  • Site Specific Construction Noise/Vibration Management Plans SSCNMPs/SSCVMPs
construction mitigation
Construction Mitigation
  • Monitoring
  • Temporary/permanent barriers
  • Shielding of individual items of equipment
  • Selection of equipment
construction mitigation continued
Construction Mitigation - continued
  • Noise sensitive activities, e.g. schools, hospitals: timing
  • Consultation/Communication
  • Miscellaneous: reversing alarms, unsecured tail gates, radios, horns, shouting
offices
Offices
  • Shanghai (2)
  • Hong Kong (1)
  • Ireland (2)
  • Great Britain (2)
  • France (1)
  • Auckland (20)
  • Wellington (5)
  • New Plymouth (1)
  • Christchurch (5)
  • Hamilton (1)
  • Melbourne (24)
  • Sydney (4)
  • Adelaide (2)
  • Perth (2)