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 |
3 |
|
Acoustical
Calibrator |
SVANTEK |
SV30A |
3 |
|
Brüel
& Kjær |
4231 |
1 |
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] |
66.7 – 70.4 |
69.9 |
75 |
|
|
ND/2019/04 |
|||||
|
ND/2019/05 |
|||||
|
CP-FLN-NMS2[2] |
57.5 – 73.3 |
59.6 |
|||
|
ND/2019/01 |
CP-KTN-NMS2[3] |
53.1 – 62.2 |
58.6 |
||
|
CP-KTN-NMS3[4] |
50.0 – 56.0 |
51.6 |
|||
|
ND/2019/01 |
CP-KTN-NMS5 |
52.6 – 57.1 |
57.2 |
||
|
ND/2019/02 |
CP-KTN-NMS6 |
56.6 – 62.4 |
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. No complaint on construction noise was received
during the reporting month, therefore No Action/Limit Level exceedance
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) |
Road Traffic Noise,
Excavator, Dump Truck, Concrete Mixer Truck, Concrete Pump Truck, Crane,
Breaker |
|
|
ND/2019/04 |
||||
|
ND/2019/05 |
||||
|
CP-FLN-NMS2[2] |
Scattered Village House
in Tong Hang (Existing) |
Road Traffic Noise,
Excavator, Crane, Electric Hand Drill, Large Exhaust Fan, Electric Saw |
||
|
ND/2019/01 |
CP-KTN-NMS2[3] |
Residential Buildings at
Ma Tso Lung (Existing) |
Road Traffic Noise,
Excavator, Roller, Crane, Dump Truck, Concrete Mixer Truck, |
|
|
ND/2019/01 |
CP-KTN-NMS3[4] |
Fung Kong Garden
(Existing) |
Road Traffic Noise,
Excavator, Dump Truck, Crane, |
|
|
ND/2019/01 |
CP-KTN-NMS5 |
N/A |
Road Traffic Noise,
Excavator, Mobile Crane, Train Noise |
|
|
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 Noise, Excavator |
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.