Design and Access Statement Site: Lyng Farm, NR20 4JE

Design and Access Statement
Site: Lyng Farm, NR20 4JE
Both day- and night-time lower fixed limits can be increased to 45 dB(A) to increase the
permissible margin above background where the occupier of the property has some financial
interest in the wind farm.
In low noise environments the day-time level of the L A90,10min of the wind farm noise should be
limited to an absolute level within the range of 35-40 dB(A). The actual value chosen within
this range should depend upon: the number of dwellings in the neighbourhood of the wind
farm, the effect of noise limits on the number of kWh generated, and the duration of the level
of exposure.
For single turbines or wind farms with very large separation distances between the turbines
and the nearest properties, a simplified noise condition may be suitable. If the noise is limited
to a L A90,10min of 35 dB(A) up to wind speeds of 10 m/s at 10 m height, then this condition alone
would offer sufficient protection of amenity, and background noise surveys would be
unnecessary.
Assessment under BWEA Standard
As a comparison, the standard BWEA assessment method is given below for the Evance R9000
Wind System.
This approach is currently being revised to bring it into line with the now more accepted ETSU-
R-97 approach used in the main body of this assessment.
Acoustic Performance Estimate for typical 4.7m/s site
Calculation
Result
Windspeed at 10 metre altitude mean
speed from NOABL database
4.7
Using Rayleigh wind distribution to
calculate the 90% windspeed at 10
metres height.
=1.72*
= 8.08
Using wind correction factor from 10m
height using a power law (in accordance
with IEC 61400-2) to estimate wind at
installation rotor centre height, H
(H=15m)
= * = 8.76
Turbine distance Noise Immission Point