2.1.1.1
The EIA study of this Project concluded
that, with the use of quieter construction plant, adverse impact would not be
anticipated at the Noise Sensitive Receivers (NSRs) as shown in Figure 2.1 during the construction
phase. Also, in the operation
phase, adverse impacts would not be anticipated.
2.1.1.2
The EM&A requirements,
methodology, equipment, monitoring locations, criteria and protocols for the
noise impacts during the construction phase of the project are presented in
this section.
2.1.1.3
Noise monitoring during the
operation phase of this Project is considered not necessary as the proposed
Workshop would not expected to generate significant noise impact to the
adjacent identified NSRs.
2.2.1.1
NSRs have been identified in
accordance with Annex 13 of the EIAO-TM which can include domestic premises,
temporary housing accommodation, educational institutions, nurseries,
hospitals, medical clinics, homes for the aged, convalescent homes, places of
public worship, libraries, courts of law, performing arts centres, auditoria,
amphitheatres, hostels and country parks.
Sensitive receivers present within the 300m study area boundary have
been identified.
2.2.1.2
The construction site is located at
2.2.1.3
According to the latest Chai Wan Outline Zoning Plan (OZP)
No.: S/H20/20, one third of the Project site is zoned as “Government,
Institution and Community (2)” and two third of the site as “Open Space”. Nevertheless, the Lands Department
(LandsD) allocated the Project site to EMSD in 2009 for a temporary period of 5
years under Temporary Land Allocation No. THK-1856. The land to
the west at the immediate vicinity of the Project site is zoned as “G/IC(2)”
use and has been selected by the Education Bureau to develop a future
educational institute in terms of proposed land use. Thus it was identified as a future NSR
with institutional use in the noise assessment during the operation phase. As the future operator is yet to be
confirmed, no information on the layout of the building is available. The NSR location is therefore selected
at its site boundary i.e. the Project boundary, where the horizontal distance
is the shortest from the identified operation noise sources for operation phase
noise impact assessment under the worst case scenario.
Table 2.1: Representative Noise
Sensitive Receivers
|
Noise Sensitive Receiver |
Type |
No. of Storeys |
Distance from Site, (m) |
|
|
1 |
Tsui
Hong House Tsui Wan Estate |
Residential |
30 |
74 |
|
2 |
Tsui
Shou House Tsui Wan Estate |
Residential |
30 |
58 |
|
3 |
|
Residential |
30 |
183 |
|
4 |
Hong
Kong Institute of Vocational Education (Chai Wan) |
Institutional |
7 |
225 |
|
5 |
Endeavourers
Chan Cheng Kit Wan KG |
Institutional |
1 |
58 |
|
6 |
SKH
Li |
Institutional |
6 |
184 |
|
7 |
Chai
Wan |
Institutional |
6 |
284 |
|
8 |
Planned
Educational Institute |
Institutional |
-- |
0 |
2.3.1
Noise Parameters and
Criteria
2.3.1.1
The construction noise level should
be measured in terms of the A-weighted equivalent continuous sound pressure
level (Leq). The Leq(30min) should be used as the monitoring parameter for the
time period from 0700-1900 hours on normal weekdays. The supplementary information for data
auditing and statistical results, e.g. L10 and L90, should be obtained for
reference. A sample data record
sheet is included in Appendix 2.1.
2.3.2
Monitoring Equipment and
Methodology
2.3.2.1
As referred to the requirements of
the Technical Memorandum (TM) issued under the NCO, the sound level meters in
compliance with the International Electrotechnical Commission Publications 651:
1979 (Type 1) and 804: 1985 (Type 1) specifications should be used for carrying
out the noise monitoring.
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. The measurements may be accepted as
valid only if the difference between calibration levels obtained before and
after the noise measurement is less than 1.0 dB.
2.3.2.2
The noise measurements should not be
made in the presence of fog, rain, wind with a steady speed exceeding 5m/s or
wind with gusts exceeding 10m/s.
The wind speed should be checked with a portable wind speed meter
capable of measuring wind speeds in m/s.
2.3.2.3
The ET is responsible for the
provision of the monitoring equipment and should ensure that sufficient noise
measuring equipment and associated instrumentation are available for carrying
out the baseline monitoring, regular impact monitoring and ad hoc
monitoring. All the equipment and
associated instrumentation should be clearly labelled.
2.3.3.1
According to the environmental
findings detailed in the EIA report of the EMSD Hong Kong Workshop Project, the
designated locations for the construction noise monitoring are listed in Table
2.2 and shown in Figure
2.2.
Table 2.2: Representative Noise
Sensitive Receivers Identified for Construction Noise Impact Monitoring
|
NSRs* |
Monitoring Location |
|
NSR 2 |
Tsui Shou House
Tsui Wan Estate |
|
NSR 4 |
Hong Kong Institute
of Vocational Education (Chai Wan) |
* NSRs = Noise Sensitive Receivers
2.3.3.2
The status and location of the noise
sensitive receivers (NSRs) may change after this EM&A Manual has been
issued. In such case, and if
changes to the monitoring locations are considered necessary, the ET should
propose alternative monitoring locations and seek the agreement from the IEC
and EPD on such proposal. When
alternative monitoring locations are proposed, they should be chosen based on
the following criteria:
·
The monitoring locations close to
the major construction works activities that are likely to have noise impacts;
·
The monitoring close to the NSRs as
defined in the EIAO-TM; and
·
The assurance of the minimal
disturbance and working under a safe condition to the occupants during the monitoring
in the vicinity of the NSRs.
2.3.3.3
The monitoring stations should
normally be at a point 1m from the exterior of the facade of the NSR and be at
a position 1.2m above ground. If
there is a problem with access to the normal monitoring position, an alternative
position should be chosen, and a correction to the measurement results should
be made. For reference, a
correction of +3dB(A) should be made to the free-field measurements. The ETL should agree with the IEC and
EPD on the alternative monitoring position and corrections adopted. Once the positions for the monitoring
stations are chosen, the baseline and impact monitoring should be carried out
at the same positions.
2.3.4.1
The ET should carry out the baseline
noise monitoring prior to the commencement of the major construction
works. The baseline noise levels
should be measured for a continuous period of at least 14 consecutive days at a
minimum logging interval of 30 minutes during daytime between 0700-1900. The Leq, L10 and L90 should be recorded
at the specified intervals. A
schedule for the baseline monitoring should be submitted to the IEC for
approval before the baseline monitoring starts.
2.3.4.2
There should not be any construction
activities in the vicinity of the monitoring stations during the baseline
monitoring. Any non-project related
construction activities in the vicinity of the monitoring stations during the
baseline monitoring should be noted and the source and location of such activities
should be recorded.
2.3.4.3
In exceptional cases, when baseline
monitoring data obtained are insufficient or questionable, the ET should liaise
with the IEC and EPD to agree on an appropriate set of data to be used as the
baseline reference.
2.3.5.1
The impact noise monitoring should
be carried out at all the designated monitoring stations when there are
project-related construction activities undertaken within a radius of 300m from
the monitoring stations. Monitoring
of Leq(30min) should be carried out at each station at 0700-1900 hours on normal
weekdays at a frequency of once a week when construction activities are
underway. Any general construction
work carried out during restricted hours is controlled by Construction Noise
Permit (CNP) under the NCO.
2.3.5.2
In case of non-compliances with the
construction noise criteria, more frequent monitoring as specified in the Event
and Action Plan should be carried out.
This additional monitoring should be continued until the recorded noise
levels show that the non-compliance is rectified or proved to be irrelevant to
the project-related construction activities.
2.3.6.1
The Action and Limit levels for the
construction noise are shown in Table 2.3.
Should non-compliances of the noise criteria occur, the action in
accordance with the Event and Action Plan in Table
2.4 should be taken.
Table 2.3: Action and Limit (A/L) Levels
for Construction Noise Monitoring
|
Time
Period |
Action
Level |
Limit Level, Leq 30mins, dB(A) |
|
0700-1900 hours on normal weekdays |
When one documented complaint is received |
75 dB(A) for
residential premises |
|
70 dB(A) for
school and 65 dB(A) during
examination period |
2.3.6.2
To account for cases in which ambient
noise levels, as identified in the baseline monitoring, approach or exceed the
stipulated Limit Levels prior to the commencement of the construction works, a
Maximum Acceptable Impact Level, which incorporates the baseline noise levels
and the identified construction noise Limit Level, may be defined and agreed
with the EPD. The amended level
would be greater than 75 dB(A) and represent the maximum acceptable noise level
at a specific monitoring station.
The correction factors for the effects of the acoustic screening and/or
architectural features of the NSRs may also be applied as specified in the
EIAO-TM.
Table 2.4: Event and Action Plan for
Construction Noise Monitoring
|
EVENT |
ACTION |
|||
|
ET(1) |
IEC(1) |
Engineer |
Contractor |
|
|
Action Level |
1. Notify the IEC and
Contractor. 2. Carry out
investigation. 3. Report the results
of investigation to the IEC and Contractor. 4. Discuss with the
Contractor and formulate remedial measures. 5. Increase monitoring
frequency to check mitigation effectiveness. |
1. Review the analysed
results submitted by the ET. 2. Review the proposed
remedial measures by the Contractor and advise the Engineer accordingly. 3. Supervise the
implementation of remedial measures. |
1. Confirm receipt of
notification of failure in writing. 2. Notify the
Contractor. 3. Require the
Contractor to propose remedial measures for the analysed noise problem. 4. Ensure remedial
measures are properly implemented.
|
1. Submit noise
mitigation proposals to the IEC. 2. Implement noise
mitigation proposals. |
|
Limit Level |
1. Notify the IEC, Engineer,
EPD and Contractor. 2. Identify sources. 3. Repeat
measurements to confirm findings. 4. Increase
monitoring frequency. 5. Carry out analysis
of the Contractor’s working procedures to determine possible mitigation to be
implemented. 6. Inform the IEC,
Engineer and EPD the causes and action taken for the exceedances. 7. Assess the
effectiveness of the Contractor’s remedial action and keep the IEC, EPD and
Engineer informed of the results. 8. If exceedance
stops, cease additional monitoring. |
1. Discuss amongst
the Engineer, ET and Contractor on the potential remedial action. 2. Review the
Contractor’s remedial action whenever necessary to assure their effectiveness
and advise the Engineer accordingly. 3. Supervise the
implementation of remedial measures. |
1. Confirm receipt of
notification of failure in writing. 2. Notify the
Contractor. 3. Require the
Contractor to propose remedial measures for the analysed noise problem. 4. Ensure remedial
measures are properly implemented. 5. If exceedance
continues, consider what portion of work is responsible and instruct the
Contractor to stop that portion of works until the exceedance is abated. |
1. Take immediate
action to avoid further exceedance. 2. Submit proposals
for remedial action to the IEC within 3 working days of notification. 3. Implement the
agreed proposals. 4. Resubmit proposals
if problems still not under control. 5. Stop the relevant
portion of works as determined by the Engineer until the exceedance is
abated. |
Note (1):
ET – Environmental Team, IEC – Independent Environmental Checker; (2) Each
step of action should be undertaken within 1 working day unless otherwise
specified.
2.4.1.1
According to the EIA report, the
construction activities would cause noise exceedances at various NSRs and,
therefore, appropriate mitigation measures and good site practices are
recommended. The Contractor should
be responsible for the design and implementation of these measures. The EMIS is included in Appendix 1.1 of this EM&A Manual
including:
·
Use of quiet plant as per the
following list. It is capable of
offering a 2-14dB(A) of noise reduction;
|
PME |
Reference |
SWL, dB(A) |
|
Concrete
lorry mixer |
BS D6/33 |
96 |
|
Concrete
pump |
BS C3/26 |
103 |
|
Dump
Truck |
BS D9/39 |
103 |
|
Tracked
excavator fitted with hydraulic rock breaker |
BS D8/13 |
110 |
|
Tracked
mobile crane (132kW, 55t) |
BS
C3/29 |
98 |
·
Use of noise barrier as per the
following list. It is capable of
offering 5-10dB(A) of noise reduction;
|
PME |
Type of Noise Barrier |
Noise Reduction, dB(A) |
|
Drill
rig, rotary type (diesel) |
Acoustic
Fabric |
-10 |
|
Concrete
pump |
Noise
Barrier / Enclosure |
-10 |
|
Tracked
excavator |
Temporary
Noise Barrier |
-5 |
·
Only well-maintained plant should be
operated on-site and plants should be serviced regularly during the
construction period;
·
Mobile plant, if any, should be
sited as far from NSRs as possible;
·
Plant known to emit noise strongly
in one direction should, wherever possible, be properly orientated so that the
noise is directed away from the nearby NSRs;
·
Use of site hoarding as a noise
barrier to screen noise at low level NSRs;
·
Machines and plant that may be in
intermittent use should be shut down between works periods or should be
throttled down to a minimum; and
·
Any material stockpiles and other
structures should be effectively utilised, wherever practicable, to screen the
noise from on-site construction activities.
·
A common plywood board with noise
absorbent lining facing the speedometer is anticipated to be enough to provide
a noise attenuation of 5 dB(A). As
the layout of the future NSR is yet to be known, a noise barrier of 0.5 m high
is suggested.
2.4.1.2
In the event of exceedances or
complaints, the Contractor should review the effectiveness of these mitigation
measures and propose, design and implement alternative or additional measures
as appropriate. The Contractor
should liaise with the ET on the alternative or additional mitigation measures,
provide them to the Engineer for approval, and implement the mitigation
measures.
2.4.1.3
During the operation phase of the
Workshop, a 1 m high noise barrier installed at the speedometer calibrator,
together with the screening effect of the roof of this Workshop with a maximum
height at approximately 6.5m, would be enough to protect the NSR at site
boundary of up to approximately 6.5 m as the motor of the speedometer
calibrator is less than 2.4m from the equipment edge. In addition, an additional noise barrier
in form of a noise curtain hanging from the supporting frame at the western
site boundary will be provided to mitigate the potential reflected noise from
the operational activities arising from the Workshop. The arrangement of these mitigations
is illustrated in Figure 4.5 of the
EIA Report which shows the cross-section between the motorcycle speedometer
calibrator and NSR 8. It should be
noted that the implementation of this mitigation would be applicable only when
NSR 8 Planned Educational Institute is in place of operation.