Forthbank Wind Energy Development - Partnerships for Renewables

Forthbank Wind Energy Development
• Where flexibility exists, activities will be separated from residential neighbours by
the maximum possible distances;
• A site management regime will be developed to control the movement of vehicles to
and from the proposed wind energy development; and
• Construction plant capable of generating significant noise and vibration levels will be
operated in a manner to restrict the duration of the higher magnitude levels.
Operational Noise
8.6.2 The selection of the final turbine to be installed at the site would be made on the basis of
enabling the relevant ETSU-R-97 noise limits to be achieved at the surrounding properties.
8.7 Assessment of Residual Significant Effects
8.7.1 Figures 8.4.A to 8.4.F (Appendix 8.4) show for each of the three noise monitoring locations,
the prediction for the corresponding assessment location with the highest predicted levels.
These predictions correspond to those already presented in Table 8.10, plotted as a function
of 10m height wind speed. The calculated noise immission levels are shown overlaid on the
day-time and night-time noise limit criterion curves. These criterion curves have been derived
by calculating best fit regression lines through the measured background noise data to give
the prevailing background noise curve required by ETSU-R-97. The noise limits have then
been set either at the prevailing measured background level plus 5 dB or at the relevant fixed
lower limit whichever is the greater.
8.7.2 The ETSU-R-97 noise limits assume that the wind turbine noise contains no audible tones.
Where tones are present a correction is added to the measured or predicted noise level before
comparison with the recommended limits. The audibility of any tones can be assessed by
comparing the narrow band level of such tones with the masking level contained in a band of
frequencies around the tone called the critical band. The ETSU-R-97 recommendations
suggest a tone correction which depends on the amount by which the tone exceeds the
audibility threshold. The turbines to be used for this site will emit noise which contains no
tones that would incur a penalty when assessed by the method specified in ETSU-R-97; this
will be included in the tender and warranty agreements for the site and should be included in
any noise conditions. Therefore no corrections for tones have been included in this
assessment.
8.7.3 Table 8.11 & Table 8.12 respectively show that the predicted wind farm noise immission levels
meet the day and night-time ETSU-R-97 derived noise limits shown in Table 8.4 and 8.5 under
all wind speeds and at all locations, based on a lower day-time limit of 35 dB(A).
November 2010 Chapter 8 Page 17
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