The document discusses the French approach to assessing noise from wind farms. It outlines key aspects of French regulation and standards, including specific limits on noise levels at wind farm neighbors' properties and near turbines. It also describes methodology used in France for noise impact studies, prediction, and control measurements, including following a new standard (NF S 31-114) that provides guidelines for studying noise from wind turbines over various conditions.

1. www.acoustique-gamba.fr
The French approach to noise assessment
Saïd Business School - Oxford, UK, 11 December 2012
Sébastien GARRIGUES, René GAMBA
sebastien.garrigues@acoustique-gamba.fr

2. www.acoustique-gamba.fr
GAMBA
Company
 French company specialising in engineering,
research development and training,
 50 employees, working in all domains of
acoustics relating to buildings, environment and
industry, and of course in wind farms,
 5 locations : Toulouse, Paris, Marseille, Angers,
Rodez
The French approach to noise assessment – EWEA Oxford, 11 december 2012 2

3. www.acoustique-gamba.fr
What we will talking about ...
- Windfarm noise : a specific approach
- French regulation and standard
- Noise impact studies
- Noise measurement control
The French approach to noise assessment – EWEA Oxford, 11 december 2012 3

4. www.acoustique-gamba.fr
A specific approach
OUTDOOR
PROPAGATION
- distance
- atmospheric absorption
- meteorological conditions
- relief effect
Regulation :
Ambiant noise –
Background noise
BACKGROUND
NOISE
- local noise emission
- faraway noise emission
The French approach to noise assessment – EWEA Oxford, 11 december 2012 4

5. www.acoustique-gamba.fr
The new french regulation : Installations classified
for the environmental protection (ICPE) - since august
2011
Limit values
To windfarm neighbours, there’s no infringement when :
either ambiant noise < 35 dB(A) ,
or for ambiant noise > 35 dB(A), when the emergence no
exceeds :
3 dB(A) for night-time period (10 PM to 7 AM)
5 dB(A) for day-time period (10 PM to 7 AM)
The French approach to noise assessment – EWEA Oxford, 11 december 2012 5

6. www.acoustique-gamba.fr
The new french regulation : Installations classified
for the environmental protection (ICPE) - since august
2011
Limit values
Near the windturbines (d=1.2*(hhub+r)), there’s no
infringement when maximumambiant noise no
exceeds :
60 dB(A) for night-time period (10 PM to 7 AM)
70 dB(A) for day-time period (10 PM to 7 AM)
The French approach to noise assessment – EWEA Oxford, 11 december 2012 6

7. www.acoustique-gamba.fr
The new french regulation : Installations classified
for the environmental protection (ICPE) - since august
2011
Tonality criteria
To the neighbours, tonality
duration should not exceed
30% of night-time or day-time
period
Third octave band from 50 to
315 Hz
from 315 to 8
KHz
emergence 10 dB 5 dB
The French approach to noise assessment – EWEA Oxford, 11 december 2012 7

8. www.acoustique-gamba.fr
French standard : NF S 31-114
Still in project since 2004 … but almost finished
The workshop consists of :
Wind turbine developers
Acoustic engineers
State representatives
The French approach to noise assessment – EWEA Oxford, 11 december 2012 8

9. www.acoustique-gamba.fr
French standard : NF S 31-114
Specific standard only for windturbine noise measurements
Correlations between
noise levels and
wind speeds
The French approach to noise assessment – EWEA Oxford, 11 december 2012 9

10. www.acoustique-gamba.fr
French standard : NF S 31-114
Analyzes for references classes Cr : set of conditions
held to characterize a homogeneous acoustic situation
and to determine the neighbourhood noise exposure, in a
representative way
Day, night, evening, end of night
Seasons
Wind direction
Specific human activities (harvests, farming activities,
trafic road, ...)
...
The French approach to noise assessment – EWEA Oxford, 11 december 2012 10

11. www.acoustique-gamba.fr
French standard : NF S 31-114
Statistical analyzes :
Selected values for each integer wind
speed : noise samples median and
average wind speed samples
Noise indicator : L50, 10mn averaged
Wind speed values : 10mn averaged
and standardized according to IEC
61400-11
At least, 10 values for each integer
windspeed to valid a median value
The French approach to noise assessment – EWEA Oxford, 11 december 2012 11

12. www.acoustique-gamba.fr
French standard : NF S 31-114
Displays calculation rules for uncertainties : Type A
(samples) and type B (metrology)
Uncertainties taking into account in the regulatory
analyzes
The French approach to noise assessment – EWEA Oxford, 11 december 2012 12

13. www.acoustique-gamba.fr
Impact studies methodology
Measurement operations
between1 and 2 weeks
among neighbours,
outdoor
for specific wind
directions (main directions)
The French approach to noise assessment – EWEA Oxford, 11 december 2012 13

14. www.acoustique-gamba.fr
Impact studies methodology
Noise prediction
Topography
Atmospheric absorption
Wind and temperature gradients
Wind direction
Ground effects
AcouSPROPA® - Gamba group
The French approach to noise assessment – EWEA Oxford, 11 december 2012 14

15. www.acoustique-gamba.fr
Impact studies methodology
Reduction modalities
For a wind direction and a reference
classe
3 m/s 4 m/s 5 m/s 6 m/s 7 m/s 8 m/s
WTG1
WTG2
WTG3
WTG4
WTG5
standard mode
stop
reduced mode
The French approach to noise assessment – EWEA Oxford, 11 december 2012 15

16. www.acoustique-gamba.fr
Noise control measurements
Measurement proceedings
According to NFS 31 114 standard
Stop and start alternation every 1 or 2 hours
Duration campaign : 7 to 10 days
Cost of production loss
The French approach to noise assessment – EWEA Oxford, 11 december 2012 16

17. www.acoustique-gamba.fr
Noise control measurements
Feedback : comparison of the noise
prediction for the wind farm with the Control
measurements
Background noise : less than +/- 3 dB(A) between initial
studies and after control measurements (3 to 5 years)
Noise prediction : generaly +/- 3 dB(A) between measure
and calculation for same weather conditions
The French approach to noise assessment – EWEA Oxford, 11 december 2012 17

18. www.acoustique-gamba.fr
Conclusion
French regulation needs a specific approach
New standard NFS 31 114 aims to bring a response
Long time measurements depending on meteorological
conditions are a good way to noise impact assessment
The French approach to noise assessment – EWEA Oxford, 11 december 2012 18

19. www.acoustique-gamba.fr
Thank you for your attention !
The French approach to noise assessment – EWEA Oxford, 11 december 2012 19