4.1
In
accordance with Updated EM&A Manual, construction noise monitoring was
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 shall be on a weekly basis and conduct one set of
measurements between 0700 and 1900 hours on normal weekdays. 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 Figure 3 and 4 according to Table 1.1 of 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 the 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 Meter was used for impact noise monitoring. The meters are 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 also complied with International Electrotechnical Commission Publications
651:1979 (Type 1) and 804:1985 (Type 1) specifications. Table 4.2 summarizes the noise monitoring equipment being 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 |
6 |
|
SVANTEK |
SVAN 957 |
1 |
|
|
Acoustical
Calibrator |
Brüel & Kjær |
4231 |
1 |
|
SVANTEK |
SV30A |
2 |
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 |
Parameter |
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
hrs 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.
·
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, the time weighting and the 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 hrs 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 Leq, L90 and L10 were recorded. In
addition, site conditions and
noise sources were 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 record 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 head of the sound level meter and calibrator were cleaned with a
soft cloth at quarterly intervals.
4.6
The
sound level meter and calibrator 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 summarized 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 summarized 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] |
67.8
– 72.7 |
69.9 |
75 |
|
|
ND/2019/04 |
|||||
|
ND/2019/05 |
|||||
|
CP-FLN-NMS2[2] |
57.6
– 70.4 |
59.6 |
|||
|
ND/2019/01 |
CP-KTN-NMS2[3] |
52.2
– 63.0 |
58.6 |
||
|
CP-KTN-NMS3[4] |
47.6
– 67.5 |
51.6 |
|||
|
ND/2019/01 |
CP-KTN-NMS5 |
54.4
– 62.6 |
57.2 |
||
|
ND/2019/02 |
CP-KTN-NMS6 |
54.2
– 69.5 |
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. No Action/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 source 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, 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 project related non-compliance of the criteria occur, action in accordance
with the Action Plan in Appendix N
shall be carried out.