6.1
Noise
Quality Parameters
6.1.1
Construction noise level shall be measured in terms
of the A-weighted equivalent continuous sound pressure level (Leq). Leq
30 min shall be used as the monitoring parameter for the time period
between 0700 and 1900 hours on normal weekdays. For all other time periods, Leq 5 min shall be employed for
comparison with the Noise Control Ordinance (NCO) criteria.
6.1.2
As supplementary information for data auditing,
statistical results such as L10 and L90 shall also be
obtained for reference.
6.2
Monitoring
Equipment
6.2.1
As referred to in the Technical Memorandum (TM)
issued under the NCO, sound level meters in compliance with the International Electrotechnical Commission Publications 651: 1979 (Type 1)
and 804: 1985 (Type 1) specifications shall be used for carrying out the noise
monitoring. Immediately prior to and following each noise measurement, the
accuracy of the sound level meter shall be checked using an acoustic calibrator
generating a known sound pressure level at a known frequency. Measurements may
be accepted as valid only if the calibration level from before and after the
noise measurement agrees to within 1.0 dB.
6.2.2
Noise measurements should be made in accordance with
standard acoustical principles and practices in relation to weather conditions.
6.2.3
The ET is responsible for the provision,
installation, operation, maintenance, dismantle of the monitoring equipment. He
shall ensure that sufficient noise measuring equipment and associated
instrumentation are available for carrying out the baseline monitoring, regular
impact monitoring and ad hoc monitoring. All the equipment and associated
instrumentation shall be clearly labelled.
6.3
Monitoring
Locations
6.3.1A The locations of construction noise monitoring stations are
summarised in Table 6.1 and
shown in Figure 6.1.
6.3.1
6.3.2
The ET shall select the monitoring location from the
above table based on the locations of the construction activities and seek
approval from ER and agreement from the IEC and EPD to the proposal. The
monitoring locations should be chosen based on the following criteria:
n
at
locations close to the major site activities which are likely to have noise
impacts;
n
close
to the most affected existing noise sensitive receivers; and
n
for monitoring locations located in the
vicinity of the sensitive receivers, care should be taken to cause minimal
disturbance to the occupants during monitoring.
6.3.3
The monitoring station shall normally be at a point
1 m from the exterior of the sensitive receiver building facade and be at a
position 1.2 m above the ground. If there is problem with access to the normal
monitoring position, an alternative position may be chosen, and a correction to
the measurements shall be made. For reference, a correction of +3 dB(A) shall be made to the free field measurements. The ET
shall agree with the IEC on the monitoring position and the corrections
adopted. Once the positions for the monitoring stations are chosen, the
baseline monitoring and the impact monitoring shall be carried out at the same
positions.
6.3.4
The ENPO may, depending on site conditions and
monitoring results, decide whether additional monitoring locations shall be
included or any monitoring locations could be removed/relocated during any stage of the construction phase.
6.4
Baseline
Monitoring for Construction Noise
6.4.1
The ET shall carry out baseline noise monitoring
prior to the commencement of the construction works. There shall not be any
construction activities in the vicinity of the stations during the baseline
monitoring. Continuous baseline noise monitoring for the A-weighted levels Leq, L10 and L90 shall be carried out daily for a period of
at least two weeks in a sample period of 5 minutes or 30 minutes between 0700
and 1900, and 5 minutes between 1900 and 0700. A schedule on the baseline
monitoring shall be submitted to the ER and IEC for approval before the
monitoring starts.
6.4.2
In exceptional cases, when insufficient baseline
monitoring data or questionable results are obtained, the ET shall liaise with
the IEC and EPD to agree on an appropriate set of data to be used as a baseline
reference and submit to the ER for approval.
6.4.3
6.4.3A The
baseline monitoring was undertaken for the Project between September and November
2011 under Agreement CE No.35/2011 (EP) ¡§Baseline Environmental Monitoring for
Hong Kong¡VZhuhai-Macao Bridge Hong Kong Projects ¡V Investigation¡¨ prior to
commencement of construction of the Project. The baseline monitoring results
obtained under Agreement CE No.35/2011 (EP) will be adopted for this Contract.
6.5
Impact
Monitoring for Construction Noise
6.5.1
During normal construction working hour (0700-1900
Monday to Saturday), monitoring of Leq, 30min noise
levels (as six consecutive Leq, 5min readings) shall
be carried out at the agreed monitoring locations once every week in accordance
with the methodology in the TM.
6.5.2
If a school exists near the construction activity,
noise monitoring shall be carried out at the monitoring stations for the
schools during the school examination periods. The ET Leader shall liaise with
the school¡¦s personnel and the Examination Authority to ascertain the exact
dates and times of all examination periods during the course of the contract.
6.5.3
In case of non-compliance with the construction
noise criteria, more frequent monitoring, as specified in the Action Plan,
shall be carried out. This additional monitoring shall be continued until the
recorded noise levels are rectified or proved to be irrelevant to the
construction activities.
6.5.4
A schedule on the compliance monitoring shall be
submitted to the ER and IEC for approval before the monitoring starts.
6.6
Event
and Action Plan for Construction Noise
6.6.1A The Action and Limit levels for
construction noise are defined in Table
6.2. Should non-compliance of the criteria occur, action in
accordance with the Action Plan in Table 6.3 shall be carried
out.
6.7
Mitigation
Measures
6.7.1
The EIA Report has recommended construction noise
control measures including the use of quiet plant and temporary noise barriers.
All the proposed mitigation measures are summarised in the EMIS in Appendix B.
6.7.2
Not applicable.
6.8
6.8.1
6.8.2
6.8.2.A
6.8.2.1
6.8.2.2
6.8.2.3
6.8.2.4
6.8.2.5
6.8.2.6
6.8.2.7
6.8.2.8
6.1A
6.2A
6.3A
6.4A
6.5A
6.6A
6.7A
6.8A
Report of
Monitoring Data to ENPO
6.8.1A This
Assignment, which involves multiple construction contracts, will be constructed
concurrently with other major infrastructures such as the HKLR and TMCLKL.
These interface projects will be overviewed by the ENPO. The ENPO will also
oversee and coordinate the cumulative environmental issues arising from the
concurrent projects.
6.8.2A To facilitate the ENPO to evaluate environmental
impacts and investigate complaints, the ET Leaders shall provide the impact
noise monitoring results within one working day after the monitoring event. The
ET Leader shall follow ENPO's requirement on the data submission format and
procedure.