3.1.1
With
reference to Section 3.5.1 of the EM&A manual, the baseline noise
monitoring shall be carried out for at least 2 weeks prior to the commissioning
of the construction works.During the baseline monitoring, there shall not be
any construction activities in the vicinity of the monitoring stations.
3.1.2
The
baseline noise monitoring parameters and frequencies are presents in Table 3.1.
3.2.1
In
accordance with Section 3 of the EM&A Manual, noise monitoring should be
carried out at 3 designated monitoring locations.
3.2.2
The
noise monitoring stations are summarised in Table 3.2 and shown in Figure 3.
3.3.2
The
model of the noise monitoring equipment used is summarized in Table
3.3.
3.3.3
The
ET is responsible for the provision of the monitoring equipment and should
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 should be clearly labelled.
3.3.4
The
monitoring procedures are as follows:
·
The monitoring station will set at a point
1m from the exterior of the sensitive receivers building façade and set at a
position 1.2m above the ground.
·
The battery condition was checked to
ensure good functioning of the meter.
·
Parameters such as frequency weighting,
the time weighting and the measurement time will set as follows:
§ frequency
weighting : A
§ time
weighting : Fast
§ measurement
time : continuous 5 minutes interval
·
Prior to and after noise measurement, the
meter shall be calibrated using the calibrator for 94.0 dB at 1000 Hz. If the
difference in the calibration level before and after measurement is more than 1.0
dB, the measurement will considered invalid and repeat of noise measurement is
required after re-calibration or repair of the equipment.
·
Noise measurement should be paused during
periods of high intrusive noise if possible and observation shall be recorded
when intrusive noise is not avoided.
·
Noise measurements shall not be made in
fog, rain, wind with a steady speed exceeding 5 m/s or wind with gusts
exceeding 10 m/s. The wind speed shall be checked with a portable wind speed
meter capable of measuring the wind speed in m/s. Calibration certificate of
the anemometer is provided in Appendix A.
3.3.5
Maintenance
and Calibration procedures are as follows:
·
The microphone head of the sound level
meter and calibrator should be cleaned with a soft cloth at quarterly
intervals.
·
The sound level meter and calibrator
should be calibrated annually by a HOKLAS laboratory.
·
Relevant calibration certificates are
provided in Appendix A.
3.4.1
Baseline
noise monitoring was conducted at three monitoring stations between 1 December
2020 and 14 December 2020. The baseline monitoring schedule is provided in Appendix
F. With reference to the Hong Kong Observatory data and site
observation, no rainy or windy (over 5m/s average wind speed) weather was
observed. The weather condition in
the monitoring period is provided in Appendix G.
3.4.2
During
the baseline monitoring, at CM1, road traffic noise along the road near the
squatter house at the north of Yuen Long STW was observed during the baseline
monitoring.
3.4.3
At
CM2, road traffic noise along the road near squatter house at the west of Yuen
Long STW was observed in the surroundings, and the contributed to the
occasional high noise levels (over 75dB (A)).
3.4.4
At
CM3, road traffic noise along the Nam Sang Wai Road was observed during the
baseline monitoring.
3.4.5
The
monitoring data are summarized in Table 3.4. Detailed noise monitoring data
are presented in Appendix C.
3.5.1
The
Action and Limit Levels were established in accordance with the EM&A
Manual. The baseline noise level shall be referenced during the compliance
check in the impact noise monitoring period. The action and limit levels for
construction noise were presents in Table 3.5.
3.6.1
The
Event and Action Plan for Noise are given in Appendix E.