Paragraph 3 I1

for each 10-minute interval for which L_A90,10min data have been obtained as provided for in paragraph 1, a tonal assessment shall be performed on noise immissions during 2-minutes of each 10-minute period. The 2-minute periods shall be regularly spaced at 10-minute intervals provided that uninterrupted clean data are available. Where clean data are not available, the first available uninterrupted clean 2 minute period out of the affected overall 10 minute period shall be selected. Any such deviations from standard procedure as described in Section 2.1 on pages 104 – 109 of ETSU-R-97 shall be reported;

for each of the 2-minute samples the margin above or below the audibility criterion of the tone level difference, L_tm (Delta L_tm), shall be calculated by comparison with the audibility criterion given in Section 2.1 on pages 104-109 of ETSU-R-97;

the margin above audibility shall be plotted against wind speed for each of the 2-minute samples. For samples for which the tones were below the audibility criterion or no tone was identified, a value of zero audibility shall be substituted;

a linear regression shall then be performed to establish the margin above audibility at the assessed wind speed for each integer wind speed. If there is no apparent trend with wind speed then a simple arithmetic average shall be used;

the tonal penalty shall be derived from the margin above audibility of the tone according to the figure below. The rating level at each wind speed shall be calculated as the arithmetic sum of the measured noise level from the authorised development, as determined from the best-fit curve described in paragraph 2, and the penalty for tonal noise.