TNAG-1613-FCO40-2221-Executive-Council-of-Hong-Kong-memoranda-and-minutes-of-meet-1987 — Page 248

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In cases where the NSR is a

building directly adjacent to the

construction site such that none of the percussive piling works will be

visible when viewed from any window, door or other opening in any facade

of the NSR, the NSR shall be considered to be partially screened and a

negative correction of 5 dB(A) shall be applied to the PNL obtained in

Step 5.

Where the latter condition applies and the NSR is separated

from the construction site by another building such that none of the

percussive piling works will be visible when viewed from any window,

door or other opening in any facade of the NSR, the NSR shall be

considered to be totally screened.

2.7

Step 7 Correction for Acoustic Reflections

A positive correction of 3 dB(A) may be applied to the PNL obtained in

Step 5 in cases where the Authority considers that noise levels at the

NSR will be increased due to the confined or reverberant nature of the

immediate locality of the construction site and the NSR.

2.8

Step 8

Corrected Noise Level (CNL) at the Noise Sensitive

Receiver (NSR)

The corrections obtained in Steps 6 and 7 shall be applied to the PNL

obtained in Step 5 to give the CNL at the NSR.

2.9 Step 9 Determination of the Permitted Hours of Operation

The CNL at the NSR obtained in Step 8 shall be compared with the ANL

obtained in Step 2 and the appropriate permitted hours of operation

shall be determined from Table 5.

The Authority may vary the timing (but not the total duration) of the

permitted hours of operation if it considers that such variation would

be justified by the nature or requirements of any NSR which may be

affected.

The timing and total duration of the permitted hours of operation may be

varied if the application is a special case as defined in Section 3.

The procedures detailed in Section 3 shall then be followed.