2. DETERMINATION OF THE PERMITTED HOURS OF OPERATION FOR PERCUSSIVE PILING
| 2.6 | Step 6 - Corrections for the Effect of Barriers In cases where the Authority considers that all of the percussive piling will be totally screened by a substantial barrier such that none will be visible when viewed from any window, door or other opening in any facade of the NSR, a negative correction of 10 dB(A) shall be applied to the PNL obtained in Step 5. Substantial barriers shall be taken to be large solid objects, such as buildings or topographical features, which will act as effective acoustic screens. Barriers which are small, lightweight, incomplete or temporary, such as site fences or hoardings, are not to be considered. In cases where the NSR is a building directly adjacent to the construction site such that none of the percussive piling 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. |
| 2.7 | Step 7 - Correction for Acoustic Reflections In cases where the NSR is a building, a positive correction of 3 dB(A) shall be applied to the PNL obtained in Step 5. An additional positive correction of 3 dB(A) may be applied to the PNL 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 or 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, if applicable, shall be determined from Table 5A or 5B. 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 or of the percussive piling under consideration. 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. |
| 2.10 | Step 10 - Construction Noise Permit (CNP) Issuing Procedure Each CNP issued by the Authority shall include as a condition the permitted hours of operation and may also include such other conditions as the Authority considers appropriate. When there is no permitted hours of operation for the use of diesel, pneumatic and/or steam hammers as determined in Step 9 above, a CNP shall not be issued. When giving consideration to the renewal of CNPs pursuant to section 8 of the Ordinance the Authority may impose additional conditions or time restrictions having regard to complaints received and other relevant factors, notwithstanding the procedures and guidelines detailed in Steps 1 to 9. |
