4.1
In accordance with the Updated EM&A
Manual, construction noise monitoring shall be conducted in terms of the A-weighted
equivalent continuous sound pressure level (Leq)
to monitor the construction noise arising from the construction activities. The
regular monitoring frequency for each monitoring station was on a
weekly basis and one set of measurements between 0700 and 1900 hours on normal
weekdays was
conducted. Appendix
B shows the established Action and Limit Levels for the environmental
monitoring works.
4.2
Impact noise monitoring was conducted at the
monitoring stations, as shown in Figures 3 and 4 according to Table 1.1 of the Updated
EM&A Manual. Table 4.1 describes the locations of
the noise monitoring stations.
Table 4.1 Location
of Noise Monitoring Stations
|
Contract No. |
Monitoring Station(s) |
Location(s) |
|
|
ND/2019/06 |
CP-FLN-NMS1[2] |
Belair Monte |
|
|
ND/2019/04 |
|||
|
ND/2019/05 |
|||
|
CP-FLN-NMS2[3] |
Scattered Village Houses in Tong Hang |
||
|
ND/2019/01 |
CP-KTN-NMS2[4] |
Residential Buildings at Ma Tso Lung |
|
|
CP-KTN-NMS3[5] |
Fung Kong Garden |
||
|
ND/2019/01 |
CP-KTN-NMS5 |
N/A |
|
|
ND/2019/02 |
CP-KTN-NMS6 |
Ho Sheung Heung, Hau Ku Shek Ancestral Hall, Hung Shing
Temple & Pai Fung Temple and Sin Wai Nunnery |
Remarks:
[1]: Noting
that construction phase noise monitoring at the other proposed monitoring
stations (e.g. planned), where access is permitted, will be conducted during construction
phase of relevant works contract(s).
[2]:
Since the distance between monitoring station and site boundary of ND/2019/03
under EP-473/2013/A exceeds 300m, the monitoring station is not applicable to
ND/2019/03.
[3]:
Since the distance between monitoring station and site boundary of ND/2019/03 and
ND/2019/04 under EP-473/2013/A exceeds 300m, the monitoring station is not
applicable to ND/2019/03 and ND/2019/04.
[4],[5]:
Since the distance between monitoring station and site boundary of ND/2019/03
under EP-468/2013/A exceeds 300m, the monitoring station is not applicable to
ND/2019/03.
4.3
Integrating Sound Level Meters were used for impact
noise monitoring. The meters were Type 1 sound level meter capable of giving a continuous readout of
the noise level readings including equivalent continuous sound pressure level (Leq) and percentile sound pressure level (Lx)
that complied with International Electrotechnical Commission Publications
651:1979 (Type 1) and 804:1985 (Type 1) specifications. Table 4.2 summarises the noise monitoring
equipment used. Copies of calibration certificates are attached in Appendix C.
Table 4.2 Noise
Monitoring Equipment
|
Equipment |
Manufacturer |
Model |
Quantity |
|
Sound Level Meter |
BSWA |
BSWA 308 |
2 |
|
Acoustical
Calibrator |
SVANTEK |
SV30A |
2 |
Monitoring
Parameters, Frequency and Duration
4.4
Table 4.3 summarises the
monitoring parameters, frequency and total duration of
monitoring. The noise monitoring
schedule is shown in Appendix D.
Table
4.3 Noise
Monitoring Parameters, Duration and Frequency
|
Contract No. |
Monitoring Stations |
Parameters[2] |
Duration |
Frequency |
Measurement |
|
|
ND/2019/06 |
CP-FLN-NMS1[3] |
L10(30 min.) dB(A) L90(30 min.) dB(A) Leq(30 min.)dB(A) (as six consecutive Leq, 5min
readings) |
0700-1900
hours on normal weekdays |
Once per week |
Façade |
|
|
ND/2019/04 |
||||||
|
ND/2019/05 |
||||||
|
CP-FLN-NMS2[4] |
||||||
|
ND/2019/01 |
CP-KTN NMS2[5] |
Free-field[1] |
||||
|
CP-KTN NMS3[6] |
||||||
|
ND/2019/01 |
CP-KTN NMS5 |
|||||
|
ND/2019/02 |
CP-KTN-NMS6 |
Façade |
Remarks:
[1]: Correction of +3dB (A) for free-field measurement.
[2]: A-weighted
equivalent continuous sound pressure level (Leq).
It is the constant noise level which, under a given situation and time period, contains the same acoustic energy as the actual
time-varying noise level.
L10 is
the level exceeded for 10% of the time. For 10% of the time, the sound or noise
has a sound pressure level above L10.
L90 is
the level exceeded for 90% of the time. For 90% of the time, the noise level is
above this level.
[3]: Since the distance between
monitoring station and site boundary of ND/2019/03 under EP-473/2013/A exceeds
300m, the monitoring station is not applicable to ND/2019/03.
[4]: Since the distance between monitoring station and
site boundary of ND/2019/03 and ND/2019/04
under EP-473/2013/A exceeds 300m,
the monitoring station is not applicable to ND/2019/03 and ND/2019/04.
[5],[6]: Since the distance between monitoring station
and site boundary of ND/2019/03 under EP-468/2013/A exceeds 300m, the
monitoring station is not applicable to ND/2019/03.
Monitoring Methodology and QA/QC Procedures
·
The microphone head of the sound level meter
was positioned at 1m from the exterior of the noise sensitive I and lowered
sufficiently so that the building’s external wall acted as a reflecting surface;
·
The
battery condition was checked to ensure the correct functioning of the meter;
·
Parameters
such as frequency weighting, time weighting and measurement time were set as follows:
—
frequency weighting : A
—
time weighting : Fast
—
time measurement :
Leq(30 min.) dB(A)
(as six
consecutive Leq, 5min readings) during non-restricted hours (i.e.
0700-1900 hours on normal weekdays)
·
Prior
to and after each noise measurement, the meter was calibrated using a
Calibrator for 94.0 dB at 1000 Hz. If the
difference in the calibration level before and after measurement was more than
1.0 dB, the measurement would be considered invalid and repeat of noise
measurement would be required after re-calibration or repair of the equipment;
·
During the monitoring
period, the values of Leq, L90 and L10 were recorded. In addition, site conditions and noise sources
were also recorded on a standard record sheet;
·
Noise
measurement was paused temporarily during periods of high intrusive noise (e.g.
dog barking, helicopter noise) if possible and observation records during measurement period should be provided; and
·
Noise
monitoring was cancelled in the presence of fog, rain, and wind with a steady
speed exceeding 5 m/s, or wind with gusts exceeding 10 m/s. The wind speed should
be checked with a portable wind speed meter capable of measuring the wind speed
in m/s.
4.5
The microphone heads of the
sound level meters and calibrators were cleaned with a soft cloth at quarterly intervals.
4.6
The sound level meters and
calibrators were checked and calibrated at yearly intervals.
4.7
Immediately prior to and following each noise
measurement, the accuracy of the sound level meter should be checked using an
acoustic calibrator generating a known sound pressure level at a known
frequency. Measurements would be accepted as valid only if the calibration
levels before and after the noise measurement agreed to within 1.0 dB.
4.8
The noise monitoring results are summarised in Table 4.4.
Detailed monitoring results and graphical presentations of noise monitoring are
shown in Appendix F. The weather
information for the reporting month is summarised
in Appendix M.
Table 4.4 Summary
Table of Noise Monitoring Results during the Reporting Month
|
Contract No. |
Monitoring Station |
Noise
Level Leq (30
min), dB(A) |
Baseline Level, dB(A) |
Limit Level, dB(A) |
|
|
ND/2019/06 |
CP-FLN-NMS1[1] |
65.6
– 67.8 |
69.9 |
75 |
|
|
ND/2019/04 |
|||||
|
ND/2019/05 |
|||||
|
CP-FLN-NMS2[2] |
56.3
– 65.6 |
59.6 |
|||
|
ND/2019/01 |
CP-KTN-NMS2[3] |
54.6
– 60.0 |
58.6 |
||
|
CP-KTN-NMS3[4] |
52.3
– 56.8 |
51.6 |
|||
|
ND/2019/01 |
CP-KTN-NMS5 |
54.6
– 61.8 |
57.2 |
||
|
ND/2019/02 |
CP-KTN-NMS6 |
53.8
– 61.4 |
55.1 |
Remarks:
[1]:
Since the distance between monitoring station and site boundary of ND/2019/03
under EP-473/2013/A exceeds 300m, the monitoring station is not applicable to
ND/2019/03.
[2]:
Since the distance between monitoring station and site boundary of ND/2019/03
under EP-473/2013/A exceeds 300m, the monitoring station is not applicable to ND/2019/03.
[3],[4]: Since the distance
between monitoring station and site boundary of ND/2019/03 under EP-468/2013/A
exceeds 300m, the monitoring station is not applicable to ND/2019/03.
4.9
All noise monitoring was conducted as
scheduled in the reporting month. One complaint on construction noise was
received during the reporting month, therefore One Action Level exceedance was
recorded. No Limit Level exceedances was recorded. The summary of exceedance record in
reporting month is shown in Appendix O.
4.10
According to our field observations, the major
noise sources identified at the designated noise monitoring stations in the reporting
month are as follows:
Table 4.5 Observation
at Noise Monitoring Stations
|
Contract No. |
Monitoring Station |
Location |
Major Noise Source |
|
|
ND/2019/06 |
CP-FLN-NMS1[1] |
Belair
Monte (Existing) |
Excavator,
dump truck, mobile crane, piling, road traffic |
|
|
ND/2019/04 |
||||
|
ND/2019/05 |
||||
|
CP-FLN-NMS2[2] |
Scattered
Village House in Tong Hang (Existing) |
Excavator,
piling, dump truck, road traffic |
||
|
ND/2019/01 |
CP-KTN-NMS2[3] |
Residential
Buildings at Ma Tso Lung (Existing) |
Dump truck, excavator, road traffic |
|
|
ND/2019/01 |
CP-KTN-NMS3[4] |
Fung
Kong Garden (Existing) |
Road traffic |
|
|
ND/2019/01 |
CP-KTN-NMS5 |
N/A |
Road traffic |
|
|
ND/2019/02 |
CP-KTN-NMS6 |
Ho Sheung Heung, Hau Ku Shek Ancestral Hall, Hung
Shing Temple & Pai Fung Temple and Sin Wai
Nunnery (Existing) |
Road traffic |
Remarks:
[2]: Since the distance between
monitoring station and site boundary of ND/2019/03 under EP-473/2013/A exceeds
300m, the monitoring station is not applicable to ND/2019/03.
[3],[4]: Since the distance
between monitoring station and site boundary of ND/2019/03 under EP-468/2013/A
exceeds 300m. The monitoring station is not applicable to ND/2019/03.
4.11
Should
any non-compliance of the criteria occur, actions in accordance with the Event/Action
Plan in Appendix N shall be carried
out.