TNAG-1613-FCO40-2221-Executive-Council-of-Hong-Kong-memoranda-and-minutes-of-meet-1987 — Page 268

(a) the level of the one-third octave band under consideration, or, the level of the highest band in the case of a pair of bands, in that pair, is not more than 15.0 dB below the level of the highest one-third octave band;

(b)

the level of the one-third octave band under consideration, or, the arithmetic average of the in the case of a pair of bands,

levels of the two bands,

is more

than 1.0 dB higher than the

level of each of the adjacent bands on either side of the band or pair of bands under consideration; and

(c)

the level difference,

known as the tonality factor,

between the level of the

consideration,

in the

or,

f

tone' under

the

and the

on

band octave one-third

case of a pair of bands, arithmetic average of the levels of the two bands,

levels of arithmetic

the adjacent bands average either side of the band or pair of bands under consideration is

3.0 dB or more.

the of

The analysis to determine if a tonal correction is necessary shall be carried out over such a time period or periods as the Authority so as to be representative of considers appropriate within the STP,

the tonal characteristics of the noise under investigation.

Where the noise under investigation is assessed to have a tonal Ctone' characteristic with a tonality factor, ftone' the correction, c

to the MNL shall be as shown in Table 4.

f

Table 4

C

Tonality Correction

tone (dB)

Ctone

'tone (dB(A))

in cases where the frequency of leach band under

consideration is below 250 Hz

in case where the frequency of each band under consider- ation is equal to or greater than 250 Hz

[greater than or equal to 3.0

and less than 6.0

3

greater than or equal to 6.0 and less than 9.0

3

greater than or equal to 9.0 and less than 12.0

9

greater than or equal to 12.0

9

9