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 |
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] |
67.0 – 69.1 |
69.9 |
75 |
|
|
ND/2019/04 |
|||||
|
ND/2019/05 |
|||||
|
CP-FLN-NMS2[2] |
66.4 – 69.6 |
59.6 |
|||
|
ND/2019/01 |
CP-KTN-NMS2[3] |
56.0 – 60.8 |
58.6 |
||
|
CP-KTN-NMS3[4] |
49.2 – 55.0 |
51.6 |
|||
|
ND/2019/01 |
CP-KTN-NMS5 |
52.3 – 55.4 |
57.2 |
||
|
ND/2019/02 |
CP-KTN-NMS6 |
57.1 – 64.2 |
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 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.