SN EN 61400-11 : 2003 AMD 1 2006

INTRODUCTION
1 Scope
2 Normative references
3 Definitions
4 Symbols and units
5 Outline of method
6 Instrumentation
   6.1 Acoustic instruments
   6.2 Non-acoustic Instruments
   6.3 Traceable calibration
7 Measurements and measurement procedures
   7.1 Measurement positions
   7.2 Acoustic measurements
   7.3 Non-acoustic measurements
8 Data reduction procedures
   8.1 Wind speed
   8.2 Correction for background noise
   8.3 Apparent sound power levels
   8.4 One-third octave band levels
   8.5 Tonality
   8.6 Directivity (optional)
9 Information to be reported
   9.1 Characterisation of the wind turbine
   9.2 Physical environment
   9.3 Instrumentation
   9.4 Acoustic data
   9.5 Non-acoustic data
   9.6 Uncertainty
Annex A (informative) Other possible characteristics of wind
        turbine noise emission
        and their quantification
Annex B (informative) Criteria for recording/playback equipment
Annex C (Informative) Assessment of turbulence intensity
Annex D (informative) Assessment of measurement uncertainty
Bibliography
Figures
Tables

Gives sound measurement procedures that enable noise emissions of a wind turbine to be characterized. Involves using measurement methods appropriate to noise emission assessment at locations close to the machine, so as to avoid errors due to sound propagation but at a distance away to allow for the finite source size.