5.1.1.1
The EM&A
requirements, methodology, equipment,
monitoring locations, criteria and protocols for the air-borne noise impacts
during the construction and operation phases of the project are presented in this section.
5.2
Monitoring Requirements
5.2.1
Noise Parameters and Criteria
5.2.1.1
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 shown in Appendix 5.1 for reference.
5.2.2
Monitoring Equipment and
Methodology
5.2.2.1
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.
5.2.2.2
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.
5.2.2.3
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.
Construction Phase
5.2.3
Monitoring Locations
5.2.3.1
According to the EIA report
of the KTE project, the designated locations
for the construction noise monitoring are listed in Table 5.1 and shown in Figures 5.1-5.3.
Table 5.1: Construction
Noise Monitoring Locations
|
ID No. |
NSRs* |
Monitoring
Location |
|
CN1 |
NSR5 |
|
|
CN2 |
NSR6 |
|
|
CN3 |
NSR11 |
|
|
CN4 |
NSR18 |
Yee Fu Building |
|
CN5 |
NSR20 |
Caritas Bianchi |
|
CN6 |
NSR22 |
Lok Do Building |
|
CN7 |
NSR27 |
Block Y, Ki Fu
Building, Whampoa Estate |
|
CN8 |
NSR48 |
Block I, |
|
CN9 |
NSR32 |
Block
13, Bauhinia Mansions, Whampoa Garden Site 11 |
|
CN10 |
NSR33 |
Block
1, Oak Mansions, Whampoa Garden Site 5 |
|
CN11 |
NSR34 |
|
|
CN12 |
NSR35 |
|
* NSRs = Noise Sensitive
Receivers.
5.2.3.2
It should be noted that no monitoring stations are
proposed around the crushing plants at the Hung Hom Finger Pier as the cumulative
predicted noise levels at the Harbourfront Horizon (NSR39) surrounding this
location would not result in an exceedance of the noise criteria.
5.2.3.3
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.
5.2.3.4
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.
5.2.4
Baseline Monitoring
5.2.4.1
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.
5.2.4.2
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.
5.2.4.3
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.
5.2.5
Impact Monitoring
5.2.5.1
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.
5.2.5.2
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.
5.2.6
Event and Action Plan
5.2.6.1
The Action and Limit levels for the construction noise are shown in Table 5.2. Should non-compliances of the noise criteria occur, the action in accordance with the Event and Action Plan
in Table
5.3 should be taken.
Table
5.2: Action and Limit (A/L) Levels
for Construction Noise Impact Monitoring
|
Time Period |
Action Level |
Limit Level |
|
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 |
5.2.6.2
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.
Operational Phase
5.2.7
Maximum Permissible Sound Power
Levels of Fixed Plant
5.2.7.1
The maximum permissible sound power levels of the
identified fixed noise sources of the KTE project have been predicted in the EIA report. The specified sound power levels should be
implemented and refined by the Contractor as appropriate to ensure that the
noise impacts associated with the fixed plant operation will comply with the noise standards stipulated in the
EIAO-TM and NCO.
5.2.8
Commissioning Test
5.2.8.1
Prior to the operation of the KTE project, the Contractor should conduct noise
commissioning tests for all major fixed noise sources. The test should be carried out by a qualified
person possessing at least 7 years of noise control experience. The noise commissioning test report should be
submitted to the ER, ET and IEC for agreement.
5.2.8.2
One set of 30-minute measurement at each monitoring
station should be conducted during the daytime and evening period (0700-2300
hours), and night-time (2300-0700 hours).
The Leq(30min) should be used as the monitoring parameter. The supplementary information for the data
auditing, statistical results, such as Lmax, L10 and L90
should also be obtained for reference.
Table 5.3: Event
and Action Plan for Construction Noise Monitoring
|
EVENT |
ACTION |
|||
|
ET(1) |
IEC(1) |
ER(1) |
Contractor |
|
|
Action Level |
1. Notify
the IEC, ER and Contractor. 2. Carry
out investigation. 3. Report
the results of investigation to the IEC and Contractor. 4. Discuss
jointly with the ER and Contractor and formulate remedial measures. 5. Increase
the monitoring frequency to check the mitigation effectiveness. |
1. Review
the monitoring data submitted by the ET. 2. Review
the construction methods and proposed redial measures by the Contractor, and
advise the ET and ER if the proposed remedial measures would be sufficient. |
1. Notify
the Contractor. 2. Require
the Contractor to propose remedial measures for implementation if required. |
1. Submit
noise mitigation proposals to the ER and copy to the IEC and ET. 2. Implement
noise mitigation proposals. |
|
Limit Level |
1. Notify
the IEC, ER and Contractor. 2. Identify
sources. 3. Repeat
measurements to confirm findings. 4. Carry
out analysis of the Contractor’s working procedures with the ER and
Contractor to determine possible mitigations to be implemented. 5. Record
the causes and action taken for the exceedances. 6. Increase
the monitoring frequency. 7. Assess
the effectiveness of the Contractor’s remedial action with the ER and keep
the IEC informed of the results. 8. If
exceedance stops, cease additional monitoring. |
1. Discuss
amongst the ER, ET and Contractor on the potential remedial action. 2. Review
the Contractor’s remedial action whenever necessary to assure their
effectiveness and advise the ER accordingly. 3. Supervise
the implementation of remedial measures. |
1. Confirm
receipt of notification of exceedance in writing. 2. Notify
the Contractor. 3. Require
the Contractor to propose remedial measures for the analysed noise problems. 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 ER and copy to the ET and 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 ER until the exceedance is
abated. |
Note (1): ET – Environmental Team, IEC – Independent
Environmental Checker, ER – Engineer’s Representative
5.3
Mitigation Measures
Construction
Phase
5.3.1.1
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.
5.3.1.2
The mitigation measures are presented in Appendix 7.5 of the EIA Report which include:
·
Use of quiet plant as per the following list. It is capable of a 3-14dB(A) reduction of
noise;
|
PME |
Reference |
SWL,
dB(A) |
|
Air
compressor |
CNP 003 |
104 |
|
Asphalt
Paver |
BS C8/24 |
101 |
|
Breaker |
BS C8/13 |
110 |
|
Bulldozer |
BS C3/27 |
109 |
|
Concrete
lorry mixer |
BS C6/33 |
96 |
|
Concrete
Pump / Grout Pump |
BS C6/36 |
106 |
|
Crane |
BS C7/114 |
101 |
|
Cutter,
circular, steel (electric) |
BS C7/78 |
106 |
|
Dump
Truck |
BS C9/39 |
103 |
|
Backhoe |
BS C3/79 |
101 |
|
Generator |
CNP 103 |
95 |
|
Vibrating
Poker, hand-held (electric) |
BS C6/40 |
98 |
|
Rock
Drill † |
Ref 1 |
108 |
|
Roller,
vibratory |
BS C8/30 |
101 |
|
Scraper |
BS C9/16 |
108 |
|
Water
pump (electric) |
CNP 283 |
85 |
† SWL for Rock Drill is made with reference to the approved EIA Report
for Tsim Sha Tsui Station Northern Subway
·
Use of temporary or fixed noise barriers with a
surface density of at least 10kg/m2 to screen noise from movable and
stationary plant. With reference to EIAO
Guidance Note No.9/2004, noise reduction of 5dB(A) and 10dB(A) can be achieved
by noise barriers for movable and stationary plant respectively;
·
Use of enclosures with covers at top and three
sides and a surface density of at least 10kg/m2 to
screen noise from generally static noisy plant such as air compressors. With
reference to EIA Guidance Note No.9/2004 it is capable of a 15dB(A) reduction
of noise;
·
Use of acoustic fabric for the silent piling
system, drill rigs, rock drills etc.
Experience from approved EIA Report for Tsim Sha Tsui Station Northern
Subway (EIA 154/2008)showed that it is capable of a 10dB(A) reduction of noise;
·
Proper fitting of silencers and mufflers on the
ventilation fans. Experience from
approved EIA Report for Tsim Sha Tsui Station Northern Subway (EIA 154/2008)
showed that it is capable of a 15dB(A) reduction of noise; and
·
Utilisation of decking for WHA Station where PMEs
would be operating under temporary traffic decking. The area where traffic decking is feasible is
shown in Figure
7.21 of the EIA Report. Experience from approved EIA Report for West
Island Line (EIA153/2008) showed that it is capable of a 20dB(A) reduction of
noise.
·
Noise
enclosures are proposed for all muckout points to mitigate the noise generated during the construction
phase. The typical setup of an enclosure
at a mucking out point is presented in Figure
7.22 of the EIA Report. It
is anticipated that the enclosure would perform in a similar manner to the
noise closure suggested for the PMEs above and, therefore, a 15dB(A) reduction
of noise has been assumed for this assessment.
·
Noise
enclosures are proposed to be installed for all rock crushers to mitigate the
noise generation during the construction phase.
The typical setup of an enclosure has been given in Figure 7.23 of the EIA Report.
It is anticipated that the enclosure would perform in a similar manner
to the noise closure suggested for the PMEs above and, therefore, would be
capable of a 15dB(A) reduction in noise.
5.3.1.3
In addition, Table 5.4 summarises all mitigation measures to be adopted
for PMEs and their respective reduction in noise levels during the construction
noise assessment.
Table 5.4: Mitigation Measures and
Assumed Effectiveness for PMEs
|
PME |
Mitigation
Measures |
Reduction Level |
|
Compressor and Pneumatic Drilling Rig |
Acoustic Fabric |
15 |
|
Piling, vibrating hammer |
Acoustic Fabric |
15 |
|
Rock Drill |
Acoustic Fabric |
15 |
|
Silent Piling System |
Acoustic Fabric |
15 |
|
Air Compressor |
Enclosure Type Noise Barrier |
15 |
|
Rock Crusher |
Enclosure Type Noise Barrier |
15 |
|
Concrete pump |
Fixed Noise Barrier |
10 |
|
Circular Saw, bench mounted |
Fixed Noise Barrier |
10 |
|
Truck |
Fixed Noise Barrier |
10 |
|
Bar bender and cutter (electric) |
Fixed Noise Barrier |
10 |
|
Conveyor belt |
Fixed Noise Barrier |
10 |
|
Generator, Super Silenced |
Fixed Noise Barrier |
10 |
|
Grout Pump |
Fixed Noise Barrier |
10 |
|
Saw, wire |
Fixed Noise Barrier |
10 |
|
Water Pump, Submersible (Electric) |
Fixed Noise Barrier |
10 |
|
Hydraulic Jack with Pump |
Fixed Noise Barrier |
10 |
|
Ventilation Fan |
Silencer |
15 |
|
Wheeled Excavator/Loader |
Temporary Noise Barrier |
5 |
|
Crane |
Temporary Noise Barrier |
5 |
|
Hydraulic Breaker |
Temporary Noise Barrier |
5 |
|
Scraper |
Temporary Noise Barrier |
5 |
|
Breaker, hand-held, mass > 10kg and < 20kg |
Temporary Noise Barrier |
5 |
|
Breaker, hand-held, mass >= 20kg and <= 35kg |
Temporary Noise Barrier |
5 |
|
Compactor, vibratory |
Temporary Noise Barrier |
5 |
|
Drill, percussive, hand-held (electric) |
Temporary Noise Barrier |
5 |
5.3.1.4
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 ER for approval, and
implement the mitigation measures.
Operational
Phase
5.3.1.5 The mitigation measures recommended for the operational phase of the KTE project is also presented in the EMIS (Appendix 1.1). These measures should be reviewed and refined by the ER and ET if there are any major design changes during the detailed design phase such that the recommended measures are adequate for alleviating any potential operational noise impacts.