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 |
6 |
|
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 |
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.
·
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] |
67.3 – 69.0 |
69.9 |
75 |
|
|
ND/2019/04 |
|||||
|
ND/2019/05 |
|||||
|
CP-FLN-NMS2[2] |
56.6 – 67.8 |
59.6 |
|||
|
ND/2019/01 |
CP-KTN-NMS2[3] |
56.0 – 61.6 |
58.6 |
||
|
CP-KTN-NMS3[4] |
58.1 – 61.4 |
51.6 |
|||
|
ND/2019/01 |
CP-KTN-NMS5 |
55.3 – 60.2 |
57.2 |
||
|
ND/2019/02 |
CP-KTN-NMS6 |
56.3 – 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. 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 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.