AS 4959-2010

1 - AS 4959-2010 ACOUSTICS-MEASUREMENT, PREDICTION AND ASSESSMENT OF NOISE FROM WIND TURBINE GENERATORS
4 - PREFACE
5 - CONTENTS
6 - 1 SCOPE
7 - 2 REFERENCED DOCUMENTS
7 - 3 DEFINITIONS
7 - 3.1 AGL
7 - 3.2 Background A weighted sound pressure level (LA90,T)
7 - 3.3 Background noise level
8 - 3.4 Cut-in wind speed
8 - 3.5 Hub height
8 - 3.6 Rated wind speed
8 - 3.7 Receiver
8 - 3.8 Relevant receiver
8 - 3.9 Time average A-weighted sound pressure level (LAeq,T)
8 - 3.10 Wind farm
8 - 3.11 Wind speed
8 - 3.12 Wind turbine generator (WTG)
8 - 4 GUIDE TO ACCEPTABLE NOISE LIMITS
8 - 4.1 General considerations
9 - 4.2 Cumulative development
9 - 4.3 Compliance checking
10 - 4.4 Special audible characteristics
10 - 5 PREDICTION OF WIND FARM NOISE
10 - 5.1 General
10 - 5.2 Indicative predictions
11 - 5.3 More complex prediction models
12 - 6 MEASUREMENT OF BACKGROUND NOISE LEVELS
12 - 6.1 Instrumentation
12 - 6.2 Determination of relevant receivers
13 - 6.3 Measurement procedure and considerations
13 - 6.3.1 General
13 - 6.3.2 Noise measurements
14 - 6.3.3 Wind speed measurements
15 - 6.3.4 Analysis of data
15 - 7 NOISE COMPLIANCE TESTING
15 - 7.1 General considerations
16 - 7.2 Special audible characteristics
16 - 7.3 Compliance testing: Methodology 1
16 - 7.3.1 General
16 - 7.3.2 Measurements
16 - 7.3.3 Data coverage
16 - 7.3.4 Analysis
17 - 7.3.5 Assessment
17 - 7.4 Compliance testing: Methodology 2
17 - 7.4.1 General
17 - 7.4.2 Measurements
18 - 7.4.3 Data coverage
18 - 7.4.4 Analysis
18 - 7.4.5 Compliance assessment
19 - 7.5 Further monitoring
19 - 8 DOCUMENTATION
19 - 8.1 Prediction of noise from wind farm
20 - 8.2 Background sound level measurement and assessment
20 - 8.3 Compliance assessment
22 - APPENDIX A - METHODOLOGY FLOW CHART
24 - APPENDIX B - WORKED EXAMPLE
24 - B1 GENERAL
24 - B2 PREDICTION OF SOUND PRESSURE LEVELS AT A TYPICAL RECEIVER LOCATION TO DETERMINE ITS RELEVANCE
28 - B3 MONITORED BACKGROUND LEVELS
28 - B3.1 Monitoring equipment
28 - B3.2 Noise data
28 - B3.3 Wind speed data
29 - B3.4 Regression Analysis
30 - B3.5 Derivation of criteria
30 - B4 COMPARISON OF WIND FARM NOISE WITH DERIVED CRITERIA
32 - B5 COMPLIANCE ASSESSMENT
32 - B5.1 General
32 - B5.2 Compliance noise measurements
33 - B5.3 Compliance wind speed measurements.
33 - B5.4 Compliance Regression Analysis
35 - APPENDIX C - MICROPHONE WINDSHIELDS, MICROPHONES AND SPECTRUM ANALYSERS
35 - C1 WIND IMPACT EFFECTS ON MICROPHONES AND SPECTRUM ANALYSERS
35 - C2 VISUAL INSPECTION OF PHYSICAL DAMAGE TO MICROPHONE WINDSHIELDS

Provides a methodology for assessing the impact of noise from wind turbine generators (WTGs) at all receivers in the vicinity of a wind farm.

This Standard provides a methodology for assessing the impact of noise from wind turbine generators (WTGs) at all receivers in the vicinity of a wind farm.This Standard deals specifically with noise from wind farms in the presence of wind-a situation that can result in large variations in measured noise levels due to the windspeed-dependence of both the background noise and wind turbine generator noise. The measured noise levels will be reasonably accurate and repeatable if the recommended methodology is followed.This Standard is applicable to both horizontal and vertical axis WTGs generating electricity. Other noise sources may be more appropriately measured and assessed using other Standards (see list of referenced documents). The scope of this Standard does not include:The methodology for sound power level measurements of WTGs (see IEC 61400-11).The methodology for measurement of other characteristics that may be present in the noise emission of WTGs such as infrasound, low frequency noise (noise outside the normal auditory range of the human ear), impulsivity, and low frequency modulation of broad band or tonal noise (see IEC 61400-11).The methodology for measuring, predicting and assessing the noise from small WTGs used as generators in standalone power systems or used for water pumping, milling or other purposes.Small WTGs are those with a swept rotor area of less than 200 m2 (See IEC 61400.2.)The methodology for measuring, predicting and assessing the noise from service equipment used at the wind farm for maintenance and construction. (See AS 1055.2 and AS 2436).The methodology for measuring, predicting and assessing the noise from other equipment such as switchyards or substations. (See AS 1055.2).Appendix A provides a flow chart of the methodology contained within this Standard.Appendix B contains an informative worked example on prediction of sound pressure levels, monitoring background levels, and compliance testing. Appendix C gives an informative guide on wind impact effects on microphones and spectrum analysers. It also gives guidance to the visual inspection of physical damage to microphone windshields.

First published as AS 4959-2010.