9.1
Potential airborne noise impacts likely to
arise from both the construction and operation phases of the Project have been
evaluated and appropriate mitigation measures have been recommended in this
section.
Environmental
Legislation, Standards and Guidelines
9.2
Noise impacts have been assessed in
accordance with the criteria and methodology given in the Technical Memoranda
(TMs) under the Noise Control Ordinance (NCO), and Annexes 5 and
9.3
The NCO, Cap. 400 and Environmental Impact
Assessment Ordinance, Cap. 499 (EIAO) provide the statutory framework for noise
control. Assessment procedures and
standards are set out in the following TMs:
Ÿ Technical Memorandum on Environmental Impact Assessment Process (EIAO-TM)
Ÿ Technical Memorandum on Noise from Construction Work other than Percussive Piling (GW-TM)
Ÿ Technical Memorandum on Noise from Percussive Piling (PP-TM)
Ÿ Technical Memorandum on Noise form Construction Work in Designated Areas (DA-TM)
Ÿ Technical Memorandum for the Assessment of Noise from Places Other Than Domestic Premises, Public Places or Construction Sites (IND-TM)
9.4
As a general principle for noise assessment
as stated in the associated Technical Memorandum, “any premises or place shall,
however, be considered to be a Noise Sensitive Receiver (NSR) only when it is
in use for its intended purpose”. Percussive piling is governed under the PP-TM
and a construction noise permit (CNP) is required in order to carry out such
work. As the issuance of a CNP by the
Noise Control Authority would depend on the compliance of percussive piling
noise impact with the limits set out within the PP-TM, the assessment of this
type of noise would not be covered in the EIA report.
9.5
The administrative and procedural control of
all blasting operations in Hong Kong is vested in the Mines Division of the
Civil Engineering and Development Department (CEDD). The Dangerous Goods
(General) Regulations, Chapter 295 also stipulates that no person shall carry
out blasting unless he possesses a valid mine blasting certificate to be issued
by the Mines Division of CEDD. The Superintendent of Mines will review the
application on a case-by-case basis before issuing the Mine Blasting
Certificate. Although there is no
statutory noise level for blasting, the noise associated with the removal of
debris and rocks are controlled under the EIAO-TM.
Construction Noise during Non-restricted Hours - EIAO-TM
9.6
Daytime general construction works (excluding
percussive piling) between the hours 0700 – 1900 on weekdays, i.e.
non-restricted hours, is controlled under the EIAO. Annex 5 of the EIAO-TM sets out the
construction noise assessment limits, which are Leq(30
min) 75dB(A) for domestic premises, hotels and hostels; and Leq(30 min) 70dB(A) for schools
during normal hours (65dB(A) during examination periods) and all other places
where unaided voice communication is required. The criteria are summarized in Table 9.1.
Table 9.1 Air-borne
Daytime Construction Noise Criteria
|
Uses |
Daytime Noise Criteria, (Leq, 30min, dB(A)) |
|
|
Domestic
premises, hotel, hostel |
75 |
|
|
Educational
Institution |
70 |
|
|
Educational
Institution (during examination) |
65 |
|
Note:
The above standards apply to uses which rely on opened windows for ventilation.
Construction Noise Standard during Restricted Hours
9.7
Between
1900 and 0700 hours and all day on Sundays and public holidays, activities
involving the use of powered mechanical equipment (PME) for the purpose of
carrying out construction work is prohibited unless a CNP has been
obtained. A CNP may be granted in cases
where the noise can be contained within the Acceptable Noise Level (ANL) at the
noise sensitive receivers (NSRs). ANLs
are assigned depending upon the Area Sensitivity Ratings (ASRs). The corresponding basic noise levels (BNLs)
for evening and night-time periods are given in Table 9.2.
Table 9.2 Construction
Noise Criteria for Activity other than Percussive Piling during Restricted
Hours
|
Time Period |
ANL on Different ASR During Restricted Hours (Leq,
30min, dB(A)) |
||
|
ASR A |
ASR B |
ASR C |
|
|
Evening (1900 to 2300 hours) [a] |
60 |
65 |
70 |
|
Night (2300 to 0700 hours) |
45 |
50 |
55 |
Notes: [a] Includes Sundays and Public Holidays
during daytime and evening.
9.8
Despite
any description or assessment made in this EIA Report on construction noise aspects,
there is no guarantee that a CNP will be issued for the Project construction.
The Noise Control Authority will consider a well-justified CNP application,
once filed, for construction works within restricted hours as guided by the
relevant TMs issued under the NCO. It will also take into account contemporary
conditions/ situations of adjoining land uses and any previous complaints
against construction activities at the site before deciding whether to grant a
CNP. Nothing in the EIA Report should bind
the Noise Control Authority in making its decision. If a CNP is to be issued, the Noise Control
Authority should include in the permit any condition it thinks fit. Failure to comply with any such conditions
will lead to cancellation of the CNP and prosecution under the NCO.
9.9
Under
the DA-TM, the use of five types of Specified Powered Mechanical Equipment
(SPME) and three types of Prescribed Construction Work (PCW) within a
designated area during restricted hours would require a valid CNP (The Project
falls within DA). The SPME includes
hand-held breaker, bulldozer, concrete lorry mixer, dump truck and hand-held
vibratory poker. The PCW are:
Ÿ Erecting or dismantling of formwork or scaffolding;
Ÿ Loading, unloading or handling of rubble, wooden boards, steel bars, wood or scaffolding material; and
Ÿ Hammering.
9.10
In
general, it should not be presumed that a CNP would be granted for carrying out
PCW within a designated area during restricted hours. The CNP may be granted for the execution of
construction works during restricted hours involving the use of PME and/or SPME
if the relevant Acceptable Noise Levels and criteria stipulated in the GW-TM
and DA-TM can be met. The construction noise criteria are presented
in Table 9.3.
Table 9.3 Construction Noise Criteria for SPME
|
Time Period |
Basic Noise Level (BNLs) |
||
|
ASR
‘A’ |
ASR
‘B’ |
ASR
‘C’ |
|
|
Evening (1900 to 2300 hours) (1) |
45 |
50 |
55 |
|
Night (2300 to 0700 hours) |
30 |
35 |
40 |
Note: (1) Includes
Sundays and Public Holidays during daytime and evening
Fixed Plant Noise during Operation Phase
9.12
More stringent criteria for fixed plant noise
impact stipulated in the EIAO-TM for planning purposes are as follows (Table 9.4).
Ÿ 5dB(A) below the appropriate ANL set out in the IND-TM (the ANL-5dB(A) criterion); or
Ÿ The prevailing background noise level (For quiet areas with noise level below the ANL - 5 dB(A) criterion).
Table 9.4 Fixed
Plant Noise Criteria
|
|
Fixed Plant Noise for Different ASR, (Leq, 30min, dB(A)) |
|||||
|
Time Period |
ANL, dB(A) |
ANL-5, dB(A) |
||||
|
ASR A |
ASR B |
ASR C |
ASR A |
ASR B |
ASR C |
|
|
Day
(0700 to 1900 hours) |
60 |
65 |
70 |
55 |
60 |
65 |
|
Evening
(1900 to 2300 hours) |
60 |
65 |
70 |
55 |
60 |
65 |
|
Night
(2300 to 0700 hours) |
50 |
55 |
60 |
45 |
50 |
55 |
9.13
The above-mentioned second criteria would
generally apply to areas with low ambient noise levels such as suburban
areas. For areas without major nearby
noise sources such as road and rail traffic, noise sensitive receivers adjacent
to these locations would be subject to low ambient noise levels which could be
lower than the ANL by more than 5 dB(A).
In order to determine the appropriate criteria for noise assessment,
background noise measurements at representative noise sensitive receivers will
be conducted. For those noise sensitive
receivers where the prevailing background noise levels are lower than ANL by
more than 5 dB(A), fixed plant noise impact would be
assessed against the prevailing background noise levels.
Description of the Existing Environment
9.14
The Project runs
from the south of the proposed Hung Hom Station (HUH)
across the Victoria Harbour to the Causeway Bay Typhoon Shelter (CBTS),
Exhibition Station (EXH) and then to Admiralty Station (ADM).
9.15
The Project area in Hung Hom
is located in well developed urban areas.
The surrounding land uses mainly comprise a mixture of commercial,
Government/Institution/Community and residential uses. Dominant noise sources
identified were the traffic noise from
9.16
The Project area on
Table 9.5 Key
Noise Sources to the Existing Environment
|
Existing Noise Sources |
Affected Areas |
|
|
|
|
Traffic noise from |
Areas around |
|
Traffic noise from |
Areas around The Metropolis Residence, |
|
|
|
|
Traffic Noise
from |
Areas along |
|
Traffic Noise
from |
Areas near Wan Chai Sport Ground to proposed EXH |
|
Traffic Noise
from surrounding roads including Queensway, |
Areas near the ADM |
9.17
Noise measurements were conducted in January
- April 2009 to record the prevailing noise levels. As observed during the measurements, ambient
noise was dominated by traffic noise from major roads. Based on the noise measurements, the prevailing
noise levels are summarised in Table 9.6.
Table 9.6 Prevailing
Noise Levels
|
Areas |
Time
Period |
Prevailing
Noise Level, dB(A) Leq, 30 mins |
|
|
||
|
Areas around |
Day & Evening |
>70dB(A) |
|
Night |
>60dB(A) |
|
|
Areas around Harbour Plaza Metropolis and Harbourfront Horizon facing |
Day & Evening |
>70dB(A) |
|
Night |
>60dB(A) |
|
|
|
||
|
Areas along |
Day & Evening |
>70dB(A) |
|
Night |
>60dB(A) |
|
|
Areas near Wan Chai Sport Ground to EXH |
Day & Evening |
>65dB(A) |
|
Night |
>55dB(A) |
|
|
Areas near the
ADM |
Day & Evening |
>70dB(A) |
|
Night |
>60dB(A) |
|
9.18
Existing and planned/committed noise
sensitive receivers within
9.19
NSRs located
closest to the subject noise sources, i.e. first layer of NSRs, would be
considered as the most critical locations.
Furthermore, the first layer of NSRs would provide acoustic shielding to
those receivers at further distance behind.
The first layer of NSRs would represent the worst-case scenario, and is
therefore selected as representative NSRs for noise assessment. Locations of the representative NSRs for
the construction phase are shown in Figure Nos. NEX2213/C/331/ENS/M52/001 to NEX2213/C/331/ENS/M52/005). The NSRs
identified for operation phase noise assessment are shown in Figure Nos. NEX2213/C/331/ENS/M52/101 to NEX2213/C/331/ENS/M52/103. Details of the representative NSRs are presented
in Table 9.7.
Table 9.7 Representative
Noise Sensitive Receivers for Air-borne Noise Assessment
|
NSR ID |
Description |
Land Use |
No. of storey |
Area Sensitive Rating |
|
|
Air-borne
Noise during Construction Phase |
|
|
|
|
|
|
|
|||||
|
HH9 |
Harbourfront Horizon
(with centralised fresh-air supply) |
Commercial/ Service Apartment |
22 |
N/A[a] |
|
|
|
|||||
|
CH1 |
|
Residential |
17 |
N/A[a] |
|
|
CH2 |
|
Residential |
19 |
N/A[a] |
|
|
CH3 |
Elizabeth House, Block C |
Residential |
21 |
N/A[a] |
|
|
CH4 |
|
Residential |
15 |
N/A[a] |
|
|
EX1 |
Causeway Centre, Block A |
Residential |
42 |
N/A[a] |
|
|
EX5 |
The |
Educational |
-[f] |
N/A[a] |
|
|
AD1 |
Ching Yi to Barrack Paget House |
Residential |
10 |
N/A[a] |
|
|
AD2 |
Regent on the Park |
Residential |
35 |
N/A[a] |
|
|
AD3 |
Jockey Club New Life
Hostel |
Hostel |
4 |
N/A[a] |
|
|
TW1 |
To Tei
Wan Village (Off-site NSR) |
Residential |
2 |
N/A[a] |
|
|
Air-borne
Noise during Operation Phase (Fixed Plant Noise) |
|||||
|
|
|||||
|
HH9b |
Harbourfront Horizon
(with centralised fresh-air supply) |
Commercial/ Service Apartment |
22 |
B[e] |
|
|
|
|||||
|
CH1 |
|
Residential |
17 |
C[b,c] |
|
|
CH2 |
|
Residential |
19 |
C[b,c] |
|
|
CH3 |
Elizabeth House, Block C |
Residential |
21 |
C[b,c] |
|
|
EX1 |
Causeway Centre, Block A |
Residential |
42 |
B[e] |
|
|
AD1 |
Ching Yi to Barrack Paget House |
Residential |
10 |
C[d] |
|
|
AD2 |
Regent on the Park |
Residential |
35 |
B[e] |
|
|
AD3 |
Jockey Club New Life
Hostel |
Hostel |
4 |
B[e] |
|
Notes:
[a] Area
sensitivity rating is not applicable as the proposed construction works would
be carried out during non-restricted hours.
[b] NSR located in urban area, and would
be indirectly affected by the influencing factors, namely
[c] NSR located in urban area, and would be
predominantly subject to the impact from various influencing factors, including
[d] NSR located in urban area; and would
be predominantly subject to the impact from the influencing factors, namely
[e] NSR located in urban area but
not affected by any influencing factors.
[f] NSR not located within a
building structure.
9.20
The potential sources of noise impact during
construction phase of the Project would mainly be the use of PME for various
construction activities. Major
construction works that would contribute to airborne construction noise impacts
would include surface works for the construction of cut and cover tunnel section of the Project and the
aboveground structures including ventilation buildings and other supporting
sites (i.e. barging points).
9.21
The key
construction activities involved at various works areas which would result in
potential construction noise impact are summarized in Table 9.8.
Table 9.8 Summary
of Key Construction Works for this Project
|
Sections |
Key Construction Items |
Nearest Representative NSR |
|
|
|
|
|
Hung Hom |
§ Demolition
of § Construction
of § Hung Hom Landfall Construction § Removal
and reinstatement of fender piers § Demolition
and reprovisioning of Freight Pier § Barging
activities at Freight Pier § Provisional
underwater blasting at south of Hung Hom Landfall |
§ NSR HH9,
Harbourfront Horizon |
|
|
|
|
|
Cross Harbour
section up to Breakwater of CBTS |
§ IMT tunnel
construction § Provisional
underwater blasting at the middle of the IMT tunnel fairway § Temporary
reclamation and C&C tunnel for a short section outside the breakwater of
CBTS |
§ NSR CH1,
§ NSR CH2,
§ NSR CH3,
Elizabeth House, Block C § NSR CH4,
|
|
Breakwater of CBTS
to SOV |
§ Temporary
reclamation and C&C tunnel at CBTS § Construction
of South Ventilation Shafts, Plant Rooms and Emergency Access (SOV) § Construction
of TBM launching shaft § Demolition
and reprovisioning of POC |
§ NSR CH1,
§ NSR CH2,
§ NSR CH3,
Elizabeth House, Block C § NSR CH4,
|
|
SOV to EXH |
§ Construction
of underground tunnel by TBM method § Aboveground
construction works § Underpinning
of vehicular bridges § Diversion/reinstate
of footbridges § Diversion/reinstate
of box culverts § Barge
activities at ex-PCWA § Temporary
mooring area at ex-PCWA |
§ NSR CH1,
§ NSR CH2,
§ NSR CH3,
Elizabeth House, Block C § NSR CH4,
|
|
EXH |
§ Construction
of underground tunnel by C&C method § Construction
of underground station by C&C method § Aboveground
construction works § Construction
of aboveground ventilation shafts § Demolition
and reprovisioning of IGH/TP |
§ NSR EX1,
Causeway Centre, Block A |
|
EXH to open space
at the junction of |
§ Construction
of underground tunnel and TBM launching shaft by C&C method § Aboveground
construction works |
§ NSR EX5,
The |
|
Open space at the
junction of |
§ Construction
of underground tunnel by TBM Method § Aboveground
construction works § Construction
of EAP at Fenwick Street Children’s Playground § Demolition
and piles removal of part of Fleet Arcade § Reinstatement
of Fleet § Demolition
of pump house and piles removal of West Sewage Screening Plant § Temporary
diversion and piles removal of box culvert |
§ NSR EX5,
The |
|
South of ADM to
Overrun Tunnel |
§ Construction
of overrun tunnel by drill & blast method § Design
and construction of the new ADM and Hong Kong Park Ventilation Building (HKB)
by South Island Line(East) (SIL(E)), except the following construction
activities: -
Fitting out works
within ADM; -
Installation of
atrium void at ADM; -
Demolition of
existing ventilation shaft X near ADM atrium; -
Construction of
overrun tunnel with spoil mucking out works at ADM and HKB; -
Construction of
SCL portion of HKB; - and Reinstatement works. |
§ NSR AD2,
Regent on the Park |
|
Casting of IMT
segments at |
§ Formation
of § Casting
IMT units § Operation
of Concrete Batching Plant and Barging Point |
§ NSR TW1, To Tei Wan Village
(Off-site NSR) |
9.22
Since the Project would be constructed
concurrently with the SCL (TAW-HUH) and SCL (MKK-HUH) at Hung Hom area as well as WDII and CWB projects on
9.23
Based on the
latest construction programme of SIL(E), the
construction of HKB and ADM under SIL(E) would be completed before commencement
of the Project construction works. As such, cumulative construction noise
impacts from the Project and SIL(E) would not be
expected.
Operation Phase – Fixed Plant Noise
9.24
According to the design information, the major fixed noise sources identified are NOV, SOV, HKB, and
exhaust/intakes of ventilation shafts and cooling facilities at the proposed
EXH and ADM.
9.25
Table 9.9 summarizes
key elements involved in operation phase that would contribute to airborne
noise impact.
Table 9.9 Summary
of Key Operation Phase Elements for this Project
|
Sections |
Key Above-ground
Operational Items |
Nearby Representative NSR |
|
|
|
|
|
HUH Station (under
podium), Hung Hung Freight Pier to Hung Hom Landfall |
§ New NOV |
§ HH9b, Harbourfront Horizon |
|
|
|
|
|
Cross Harbour Tunnel up to Breakwater of Causeway Bay
Typhoon Shelter |
§ New SOV |
§ NSR CH1,
§ NSR CH2,
§ NSR CH3,
Elizabeth House, Block C |
|
Breakwater of |
||
|
POC to Wanchai Sports Ground |
||
|
Wanchai Sports
Ground to EXH & EXH |
§ New EXH
ventilation shafts and cooling facilities |
§ NSR EX1,
Causeway Centre, Block A |
|
EXH to |
§ Nil |
§
N/A |
|
|
§
New ADM
transformer bay, ventilation shafts and cooling facilities near Harcourt
Garden/Citic Tower |
§
NSR AD1, Ching
Yi to Barrack Paget House |
|
South of ADM to Overrun Tunnel |
§
New |
§
NSR AD2, Regent
on the Park §
NSR AD3, Jockey
Club New Life Hostel |
Assessment
Methodology
Air-borne Noise during Construction Phase
9.26
The
methodology for the noise impact assessment is in accordance with the
procedures outlined in the GW-TM. The general approach is summarized below:
Ÿ Locate the NSRs which would most likely be affected by noise from the construction work;
Ÿ Determine the items of PME for each discrete construction activity, based on available information or agreed plant inventories;
Ÿ Assign sound power levels (SWLs) to the proposed PME according to the GW-TM or other sources;
Ÿ Calculate distance attenuation to NSRs from notional noise source;
Ÿ Apply corrections in the calculations such as potential screening effects and acoustic reflection, if any;
Ÿ Predict construction noise levels at NSRs in the absence of any mitigation measures;
Ÿ
Consider cumulative impact from
concurrent projects within
Ÿ Compare the cumulative construction noise level against the noise criteria and propose suitable mitigation measures.
9.27
SWLs of the equipment will be made reference
from Table 3 of GW-TM. Where no relevant
SWL to be found in the GW-TM, reference will be made to British Standard 5228:Part 1:2009 Noise
Control on Construction and Open Sites and previous similar studies or from
measurements taken at other sites in
9.28
The construction
programme and plant inventory as presented in Appendices 3.4
and 9.2 respectively for various construction activities
were developed by the Preliminary Design Consultants of the Project Proponent. The
proposed plant inventory has been confirmed as being practical and adequate for
completing the works within the scheduled timeframe.
9.29
It was
assumed that all PME items required for a particular construction activity
would be located at the notional or probable source position of the segment
where such activity is to be performed.
The assessment was based on the cumulative SWL of PME likely to be used
for each location, taking into account the construction period in the vicinity
of the receiver location. To predict the
noise level, PME was divided into groups required for each discrete
construction task. The objective was to identify the worst case scenario
representing those items of PME that would be in use concurrently at any given
time. The sound pressure level of each construction task was calculated,
depending on the number of plant and distance from receivers. The noise levels
at NSRs were then predicted by adding up the SWLs of all concurrent
construction tasks. Noise sources from the areas greater than
9.30
A
positive 3 dB(A) façade correction was added to the
predicted noise levels in order to account for the facade effect at each NSR.
The unmitigated construction noise impacts at the identified NSRs were
predicted accordingly. Practicable direct mitigation measures including use of
quieter equipment, movable barriers, enclosures and quieter alternative methods
were considered if exceedance of relevant criteria
was predicted. In case where the mitigated noise levels still exceeded the
relevant criteria, the duration of the noise exceedance
would be estimated.
Fixed Plant Noise during Operation Phase (
9.31
In the
absence of any detailed information and noise specification of the proposed
fixed plant at the time of this EIA, the maximum permissible noise emission
levels was therefore determined for future detailed design of the fixed plant.
9.32
For
the assessment of noise from the fixed plant, the maximum permissible sound
power levels (Max. SWLs) of the identified fixed noise sources have been
determined using the standard acoustics principles. The following formula was used for
calculating the Max. SWLs of the fixed plant.
SPL = Max SWL – DC +
FC – BC
Where
|
SPL |
Sound Pressure Level, in
dB(A) |
|
Max. SWL |
Maximum Permissible Sound
Power Level, in dB(A) |
|
DC |
Distance Attenuation, in
dB(A) (i.e 20 log D + 8 [where D is the distance in
metres]) |
|
FC |
Facade Correction, in dB(A) (i.e. 3 dB(A)) |
|
BC |
Barrier Correction, in dB(A) |
9.33
Being
the worst case scenario, it is assumed that all the fixed plant within the same
location would be operated concurrently.
Screening correction offered by buildings or other structures such as
office and residential building will be taken into account in calculating the
predicted noise levels. According to the
GW-TM, effective barriers can result in noise reduction of 5 to 10 dB(A) for the fixed plant depending on the line of sight of
the representative NSRs. A positive 3 dB(A) correction will be added to predicted noise levels at
the NSRs due to the facade effect.
9.34
The fixed plant noise assessment of proposed
ADM ventilation shafts and HKB induced from operation of SIL(E) have been conducted under SIL(E) EIA. To account for the cumulative
fixed plant noise contributed from nearby existing and planned fixed plant
noise sources, the following design target which have been considered in the
SIL(E) EIA report will be adopted in this assessment:
Ÿ Noise criteria -6 dB(A), i.e. ANL -5-6 dB(A), are applied for NSRs near ADM due to the cumulative impact from the fixed plants of existing ADM and the planned SIL(E); and
Ÿ Noise criteria -3 dB(A), i.e. ANL-5-3 dB(A), are applied for NSRs near HKB due to the cumulative impact from the fixed plants of the planned SIL(E).
9.35
By
meeting the above design target, the cumulative fixed plant noise impact on NSRs
adjacent to ADM and HKB could meet the EIAO-TM noise criteria. Therefore, it is expected that there would
not be any adverse cumulative impacts from the Project and the nearby existing
and planned fixed plant noise sources of SIL(E).
9.36
Corrections
of tonality, intermittency or impulsiveness have not been applied owing to the
lack of design/supplier information at this preliminary design stage. If the noise exhibits any of these
characteristics during operation of the plant, the noise limit of the plants should
be reduced in accordance with the recommendation given in Section 3.3 of
IND-TM.
9.37
The
predictions of construction noise impacts were based on the methodologies
described in the GW-TM under the NCO.
The methodology which had previously been applied in other EIA studies
is generally accepted for use in assessing construction noise impact against
EIAO-TM noise criteria. In carrying out
the assessment, realistic worst case assumptions have been made in order to
provide a conservative assessment of noise impacts. The construction noise impact was assessed
based on conservative estimates for the types of plant and methods of
working.
9.38
For
fixed plant noise assessment, it has been carried out by determining the
maximum permissible noise emission levels for future detailed design of the
fixed plant in the absence of any detailed information and noise specification
of the proposed fixed plant at the time of this EIA study. For determining the
distance correction factors, the horizontal distances between the noise source
positions and the NSRs were used for representing the worst level of the
representative NSRs.
9.39
There
would be some limitations such as the accuracy of the predictive base data for
future conditions e.g. plant inventory for the proposed construction works and
fixed plant for future operation. Uncertainties in the assessment of impacts
have been considered when drawing conclusions from the assessment.
Airborne
Noise Impact Assessment
Construction Phase during Non-restricted Hours
9.40
To strike a
balance between the need for providing a railway system to the public and the
public concerns on the adverse impacts, the following key features have been
considered during the design of the Project to alleviate the construction noise
impacts as far as practicable:
·
Minimisation of
number of PME; and
·
Works would be
implemented in phases, where possible, in order to reduce the number of PME
required to be on-site.
9.41
The unmitigated noise
levels at representative NSRs have been predicted and are presented in Table 9.10 based on
construction programme and plant inventory as shown in Appendices 3.4
and 9.2 respectively. Locations of notional sources and distance to
NSRs are shown in Appendix 9.3 and
corresponding figures.
9.42
The sample calculations
and the summary of unmitigated construction noise levels during non-restricted
hours for the representative NSRs are presented in Appendices 9.4
and 9.5, respectively.
Table 9.10 Unmitigated
Construction Noise Levels due to the Project during Non-restricted Hours
|
NSR ID |
Description |
Predicted Unmitigated Construction Noise
Levels, dB(A) |
EIAO-TM Noise Criteria, dB(A)(a) |
|
|
|||
|
HH9 |
Harbourfront Horizon |
62 - 75 |
75 |
|
|
|||
|
CH1 |
|
52 - 85 |
75 |
|
CH2 |
|
59 - 86 |
75 |
|
CH3 |
Elizabeth House, Block C |
62 - 84 |
75 |
|
CH4 |
|
61 - 73 |
75 |
|
EX1 |
Causeway Centre, Block A |
64 - 87 |
75 |
|
EX5 |
The |
69 - 84 |
75 |
|
AD1 |
Ching Yi to Barrack Paget House |
70 - 73 |
75 |
|
AD2 |
Regent on the Park |
69 - 85 |
75 |
|
AD3 |
Jockey Club New Life
Hostel |
67 - 82 |
75 |
|
TW1 |
To |
52 |
75 |
(a) Bolded predicted noise level represents exceedance
of the EIAO-TM Noise criteria.
9.43
The predicted noise
levels at the representative NSRs would range from 52 to 87 dB(A), and some of
the representative NSRs on Hong Kong Island would exceed the EIAO-TM noise
criteria by up to 12 dB(A). Mitigation
measures are considered necessary in order to abate the construction noise
impacts on the affected NSRs.
Construction Phase during Restricted Hours
9.44
According to the
construction programme, most of the proposed construction works will be carried
out during non-restricted hours. Certain
construction works would be carried out during restricted hours in order to
minimise the impact on local traffic during normal peak hours. In case of any construction activities during
restricted hours (1900 – 0700), it is the Contractor’s responsibility to ensure
compliance with the NCO and the relevant TMs. The Contractor will be required
to submit CNP application to the Noise Control Authority and abide by any
conditions stated in the CNP, should one be issued.
Operation Phase – Fixed Plant Noise
9.45
Locations
of fixed noise sources and relevant concerned NSRs are shown in Figure Nos. NEX2213/C/331/ENS/M52/104 to
NEX2213/C/331/ENS/M52/108. Preliminary
findings are discussed in the following sections.
9.46
Most of the premises around the proposed NOV are noise sensitive
developments including hotels and service apartment. These NSRs are air-conditioned and do not
rely on openable windows for ventilation, and hence
they were not identified as NSRs for airborne noise impact assessment. The nearest affected NSR would be NSR HH9b, Harbourfront Horizon. It is expected that fixed plant noise impact
from the operation of the proposed HUH which is considered under SCL (MKK-HUH)
project would result in cumulative impact on NSR HH9b. The potential cumulative fixed plant noise
impact arising from the operation of the HUH and NOV was therefore considered
in this assessment.
9.47
Based on the backward calculation findings, the maximum sound
power levels of the fixed plant noise sources of the proposed NOV is presented
in Table
9.11 respectively. Detailed noise calculations for
daytime and evening and night-time operations are shown in Appendices 9.6 and 9.7, respectively.
Table 9.11 Fixed
Plant Noise Design Criteria for NOV
|
Predicted
Maximum Allowable Sound Power Level, dB(A)[1] |
|||
|
NOV VS1 |
Top opening |
100 |
90 |
|
NOV VS2 |
Top opening |
||
Remark:
[1] If the noise exhibits any tonality, intermittency or impulsiveness
characteristics during the operation of the plant, the noise design limit should
be reduced to absorb these corrections in accordance with the recommendation
given in IND-TM.
South Ventilation Shaft, Plant Rooms
and Emergency Access (SOV) (Figure No. NEX2213/C/331/ENS/M52/106)
9.48
The nearest NSR affected by the fixed plant noise
sources of proposed SOV at the POC would be NSR CH2,
Table 9.12 Noise
Design Criteria for Fixed Plant at SOV
|
Predicted
Maximum Allowable Sound Power Level, dB(A)[1] |
|||
|
North |
98 |
88 |
|
Remark:
[1] If the noise exhibits any tonality, intermittency or impulsiveness
characteristics during the operation of the plant, the noise design limit
should be reduced corrections in accordance with the recommendation given in
Section 3.3 of IND-TM.
Exhibition Station (Figure
No. NEX2213/C/331/ENS/M52/107)
9.49
The nearest NSR affected by the ventilation shafts
at the EXH would be NSR EX1, Block A of Causeway Centre.
Based on the backward calculation findings, the maximum allowable sound power
levels of fixed plant noise sources of EXH are shown in Table 9.13.
Detailed noise calculations for daytime and evening and night-time
operations are shown in Appendices 9.6 and 9.7, respectively.
Table 9.13 Noise
Design Criteria for Fixed Plant at EXH
|
Predicted
Maximum Allowable Sound Power Level, dB(A)[1] |
|||
|
EXH VS14 |
South |
99 |
89 |
|
EXH VS15 |
East |
98 |
88 |
|
EXH VS16 |
West |
94 |
84 |
|
EXH VS17 |
Top opening |
95 |
85 |
|
EXH VS18 |
Top opening |
95 |
85 |
|
EXH VS19 |
Top opening |
94 |
84 |
|
EXH VS20 |
South |
94 |
84 |
|
EXH VS21 |
North |
99 |
89 |
|
EXH VS21 |
Northeast |
99 |
89 |
|
EXH VS22 |
East |
100 |
90 |
|
EXH VS23 |
East |
100 |
90 |
|
EXH VS24 |
East |
100 |
90 |
|
EXH VS25 |
East |
100 |
90 |
|
EXH VS26 |
East |
100 |
90 |
Remark:
[1] If the noise exhibits any tonality, intermittency or impulsiveness
characteristics during the operation of the plant, the noise design limit should
be reduced to take into account these corrections in accordance with the
recommendation given in Section 3.3 of IND-TM.
Admiralty Station (Figure No. NEX2213/C/331/ENS/M52/108)
9.50
The nearest NSR affected by the ventilation shafts
at the ADM would be NSR AD1, Ching Yi to Barrack Paget House. The design target discussed in Section 9.34 have been adopted to account for cumulative
impact induced from SIL(E) facilities at ADM. Based on the backward calculation findings,
the maximum allowable sound power levels of fixed plant noise sources of the
facilities under this Project are shown in Table 9.14.
Detailed noise calculations for daytime and evening and night-time
operations are shown in Appendices 9.6 and 9.7, respectively.
Table 9.14 Noise
Design Criteria for Fixed Plant at ADM
|
Predicted
Maximum Allowable Sound Power Level, dB(A)[1] |
|||
|
ADM VS6 |
Southwest |
99 |
89 |
|
ADM VS6 |
West |
102 |
92 |
|
ADM VS6 |
Northwest |
102 |
92 |
|
ADM VS7 |
Top opening |
100 |
90 |
|
ADM VS8 |
Northeast |
100 |
90 |
|
ADM VS8 |
Southwest |
99 |
89 |
|
Cooling Tower |
Top opening |
100 |
90 |
|
West |
100 |
90 |
|
Remark:
[1] If the noise exhibits any tonality, intermittency or impulsiveness
characteristics during the operation of the plant, the noise design limit should
be reduced to take into account these corrections in accordance with the
recommendation given in Section 3.3 of IND-TM.
Hong Kong Park Ventilation Building (Figure No. NEX2213/C/331/ENS/M52/108)
9.51
The nearest NSR affected by the ventilation shaft
at the HKB under this Project would be NSR AD2, Regent on the Park. The design target discussed in Section 9.34 have been adopted to account for cumulative
impact induced from SIL(E) facilities at HKB. Based on the backward calculation findings,
the maximum allowable sound power levels of fixed plant noise sources of the facilities
for this Project are shown in Table 9.15.
Detailed noise calculations for daytime and evening and night-time
operations are shown in Appendices 9.6 and 9.7 respectively.
Table 9.15 Noise
Design Criteria for Fixed Plant at HKB
|
Predicted
Maximum Allowable Sound Power Level, dB(A)[1] |
|||
|
HKB VS2 |
Northeast |
98 |
88 |
|
HKB VS2 |
Northwest |
98 |
88 |
|
HKB VS3 |
Southeast |
96 |
86 |
Remark:
[1] If the noise exhibits any tonality, intermittency or impulsiveness
characteristics during the operation of the plant, the noise design limit
should be reduced to take into account these corrections in accordance with the
recommendation given in Section 3.3 of IND-TM.
9.52
If there is any change in engineering design
information during detailed design stage or fitting-out stage, the fixed source
noise design should be reviewed by engineer/contractor to ensure the NCO and
EIAO criteria could be met in the future.
9.53
By
meeting the maximum allowable SWLs specified in Table 9.11, 9.14 and 9.15, the cumulative fixed plant noise impact on NSRs adjacent
to NOV, ADM and HKB could meet the EIAO-TM noise criteria. Therefore, it is expected that there would
not be any adverse cumulative impacts from the Project and the nearby existing
and planned fixed plant noise sources of SCL(MKK-HUH)
and SIL(E).
Recommended Mitigation Measures
Air-borne Noise during Construction Phase
9.54
The construction noise assessment indicated
that, in the absence of any mitigation measures, there would be exceedance of the construction noise criteria at some of
the NSRs on
Good Site Practice
Ÿ Only well-maintained plant shall be operated on-site and plant shall be serviced regularly during the construction program;
Ÿ Silencers or mufflers on construction equipment shall be utilized and shall be properly maintained during the construction program;
Ÿ Mobile plant, if any, shall be sited as far from NSRs as possible;
Ÿ Machines and plant (such as trucks) that may be in intermittent use shall be shut down between work periods or shall be throttled down to a minimum;
Ÿ Plant known to emit noise strongly in one direction shall, wherever possible, be orientated so that the noise is directed away from the nearby NSRs; and
Ÿ Material stockpiles and other structures shall be effectively utilized, wherever practicable, in screening noise from on-site construction activities.
Adoption of Quieter PME
9.56
In order to reduce the excessive noise
impacts at the affected NSRs during normal daytime working hours, quieter PME are
recommended. The Contractors may use
other types of quieter plant which have the same total SWL instead of specific
items of quieter plant adopted in this assessment, to meet their needs. The quieter PME adopted in the assessment
were taken from the BS5228: Part 1:2009 (Appendix 9.8 refers). It should be noted that the quieter PME
selected for the assessment could be found in
9.57
A list of quieter PME recommended for
adoption during the construction phase is presented in Table 9.16.
Table 9.16 Quieter PME Recommended for Adoption during
Construction Phase
|
PME |
Reference |
SWL, dB(A) |
|
Crane lorry, mobile |
BS D7/101 |
94 |
|
Crane, mobile |
BS D7/101 |
94 |
|
Asphalt paver |
BS D8/24 |
101 |
|
Backhoe with
hydraulic breaker |
BS D8/13 |
110 |
|
Breaker, excavator
mounted (hydraulic) |
BS D8/13 |
110 |
|
Hydraulic
breaker |
BS D8/13 |
110 |
|
Concrete lorry mixer |
BS D6/33 |
96 |
|
Poker, vibrator,
hand-held |
BS D6/40 |
98 |
|
Concrete pump |
BS D6/36 |
106 |
|
Crawler crane,
mobile |
BS D7/112 |
102 |
|
Mobile crane |
BS D7/112 |
102 |
|
Dump truck |
BS D9/24 |
104 |
|
Excavator |
BS D3/35 |
106 |
|
Truck |
BS D9/39 |
103 |
|
Rock drill |
Ref 1 |
108 |
|
Lorry |
BS D9/19 |
102 |
|
Wheel loader |
BS D3/59 |
105 |
|
Roller Vibratory |
BS D8/30 |
101 |
Note:
Ref 1: SWL for Rock Drill is
made reference to the approved EIA Report of “Tsim Sha Tsui Station Northern Subway” (Register No.: AEIAR-127/2008)
Use of
Movable Noise Barrier
9.58
The use of movable barrier for certain PME
could further alleviate the construction noise impacts. In general, 5dB(A)
reduction for movable PME and 10dB(A) for stationary PME can be achieved
depending on the actual design of movable noise barrier.
9.59
Table 9.17 shows the
assumed noise reduction effects achieved by the use of movable noise barrier
for certain items of PME. The Contractor
shall be responsible for design of the movable noise barrier with due consideration
given to the size of the PME and the requirement of intercepting the line of
sight between the NSRs and PME. Barrier
material of surface mass in excess of 14 kg/m2 is recommended to
achieve the predicted screening effect.
Use of Noise Insulating Fabric
9.60
Noise
insulating fabric (the Fabric) would be adopted for certain PME (e.g. drill
rig, rotary type etc). The Fabric shall be lapped such that there would be no
opening or gaps on the joints. With
reference to MTRC Contract C4420 Tsim Sha Tsui Modification Noise Assessment Report for Variation
of Environmental Permit (July 2003) and the technical data from manufacturer, a
noise reduction of over 10 dB(A) could be achieved
with the use of the Fabric. As a
conservative approach, a noise reduction of 10 dB(A)
for the PME lapped with the Fabric was assumed in this assessment.
9.61
A
summary of the assumed noise reduction effects achieved by the use of movable
noise barrier and the Fabric for certain item of PME is presented in Table 9.17.
Table 9.17 Noise Mitigation Measures for Certain PME
during Construction Phase
|
PME |
Mitigation Measures
Proposed |
Noise Reduction,
dB(A) |
|
Air
compressor |
Movable Barrier |
10 |
|
Asphalt
paver |
Movable Barrier |
5 |
|
Backhoe
with hydraulic breaker |
Movable Barrier |
5 |
|
Bar
Bender |
Movable Barrier |
10 |
|
Bar
bender and cutter (electric) |
Movable Barrier |
10 |
|
Breaker,
excavator mounted |
Movable Barrier |
5 |
|
Concrete
pump |
Movable Barrier |
10 |
|
Concrete
pump, stationary/lorry mounted |
Movable Barrier |
10 |
|
Drill
rig, rotary type |
Fabric |
10 |
|
Excavator |
Movable Barrier |
5 |
|
Generator |
Movable Barrier |
10 |
|
Grout
pump |
Movable Barrier |
10 |
|
Hand
held breaker |
Movable Barrier |
5 |
|
Hydraulic
breaker |
Movable Barrier |
5 |
|
Piling,
diaphragm wall, bentonite filtering plant |
Fabric |
10 |
|
Piling,
diaphragm wall, grab and chisel |
Fabric |
10 |
|
Piling,
diaphragm wall, hydraulic extractor |
Fabric |
10 |
|
Piling, large
diameter bored, grab and chisel |
Fabric |
10 |
|
Piling, hydraulic
extractor |
Fabric |
10 |
|
Piling, earth auger, auger |
Fabric |
10 |
|
Rock
drill, crawler mounted (pneumatic) |
Fabric |
10 |
|
Saw,
concrete |
Movable Barrier |
10 |
|
Front
end loader |
Movable Barrier |
5 |
Mitigated Construction Noise Impacts
9.62
Having
taken into account the noise reduction achieved by the above-mentioned
mitigation measures, the total SWLs of each activity were predicted and are
presented in Appendix 9.8. In view of the nature and limited
scale of the above recommended direct noise mitigation measures, adverse side
effects and constraints due to the inclusion of these mitigation measures would
not be expected. The predicted noise levels resulting from the
Project itself at all the representative NSRs would comply with the EIAO-TM
noise criteria. No adverse impact would
be anticipated at any existing and planned/committed NSRs within 300m from the
Project works area. Mitigated
construction noise levels during non-restricted hours at NSRs are summarized in
Table 9.18. Sample calculations and summary of mitigated construction
noise levels are presented in Appendix 9.9 and Appendix 9.10 respectively.
Table 9.18 Mitigated Construction Noise Levels due to the Project during Non-restricted Hours
|
NSR ID |
Description |
Predicted Mitigated Construction Noise Levels, dB(A) |
EIAO-TM Noise Criteria, dB(A) |
|
|
|||
|
HH9 |
Harbourfront Horizon |
62 - 71 |
75 |
|
|
|||
|
CH1 |
|
52 - 73 |
75 |
|
CH2 |
|
55 - 75 |
75 |
|
CH3 |
Elizabeth House, Block C |
52 - 74 |
75 |
|
CH4 |
|
54 - 68 |
75 |
|
EX1 |
Causeway
Centre, Block A |
57 - 75 |
75 |
|
EX5 |
The |
58 - 71 |
75 |
|
AD1 |
Ching Yi to Barrack Paget House |
58 – 61 |
75 |
|
AD2 |
Regent on the Park |
56 - 72 |
75 |
|
AD3 |
Jockey Club New Life
Hostel |
53 - 70 |
75 |
|
TW1 |
To |
52 |
75 |
Cumulative
Construction Noise Impact
9.63
The concurrent
projects in the vicinity of the Project works area at Hung Hom
include the SCL (MKK-HUH) and SCL (TAW-HUH). Construction of the SCL (MKK-HUH)
in the vicinity would involve the construction of approach tunnel, underground
platform/station, ventilation shafts and cooling towers and operation of
barging point at Hung Hom Freight Pier. Construction
of the SCL (TAW-HUH) in the vicinity would involve construction of cut and
cover tunnel at HUH.
9.64
Cumulative
construction noise impacts from these two concurrent works were assessed by
using the mitigated construction noise levels predicted in the EIA Reports of SCL (MKK-HUH) and SCL (TAW-HUH) during the overlapping
period. The predicted construction noise levels from the SCL (MKK-HUH) and SCL
(TAW-HUH) during the overlapping period are provided in Appendix 9.11.
9.65
Table
9.19 summarises
the cumulative noise levels from the Project, SCL (TAW-HUH) and SCL
(MKK-HUH). Detailed calculation of the
cumulative noise impacts are presented in Appendix 9.12. The results indicate that the cumulative
construction noise levels at the representative NSR would comply with the
EIAO-TM noise criteria.
Table 9.19 Cumulative
Construction Noise Levels during Construction
Period –
|
NSR ID |
EIAO-TM
Noise Criteria, dB(A) |
Predicted Noise Levels arising from, dB(A), Leq(30mins) |
Cumulative Noise Level, dB(A) |
||
|
The
Project |
SCL
(MKK-HUH) |
SCL
(TAW-HUH) |
|||
|
HH9 |
75 |
62-71 |
64-73 |
50 – 54 |
64-73 |
9.66
The
concurrent projects in the vicinity of the Project works area at
9.67
All NSRs
identified on
9.68
Cumulative
construction noise impacts from WDII and CWB projects were assessed by using
the mitigated construction noise levels predicted in the approved WDII &
CWB EIA Report during the overlapping period as shown in Appendix 9.11.
9.69
Table 9.20 summaries the cumulative noise levels from the Project,
WDII and CWB projects. Detailed calculation of the cumulative noise impacts are
presented in Appendix 9.13. The results indicated that cumulative
construction noise levels at all representative NSRs would comply with the
EIAO-TM criteria, except for NSR EX1 which would exceed the noise criterion by
1dB(A).
Table 9.20 Mitigated
Cumulative Construction
Noise Levels –
|
|
EIAO-TM
Noise Criteria, dB(A) |
Predicted
Noise Levels arising from, dB(A) |
Cumulative Noise Level, dB(A)(b) |
|
|
NSR ID |
The
Project |
WDII
& CWB Projects[a] |
||
|
CH1 |
75 |
52 - 73 |
58 - 69[c] |
55 - 74 |
|
CH2 |
75 |
55 - 75 |
58 - 69[c] |
57 - 75 |
|
CH3 |
75 |
52 - 74 |
58 - 69 |
52 - 74 |
|
CH4 |
75 |
54 - 68 |
63 - 75 |
55 - 75 |
|
EX1 |
75 |
57 - 75 |
65 - 73 |
57 - 76 |
|
EX5 |
75 |
58 - 71 |
53 - 72 |
63 - 73 |
Note:
(a) Mitigated construction noise levels from WDII and CWB projects at the
particular NSR within the overlapping period are based on the approved WDII
& CWB EIA Report.
(b) Bolded predicted noise levels represent exceedance
of the EIAO-TM Noise criteria.
(c) Since no construction noise level was predicted at CH1 and CH2 in the
approved WDII & CWB EIA Report, the mitigated construction noise levels at
the nearest NSR (CH3) was adopted to predict the cumulative construction noise
levels from WDII and CWB projects.
Operation Phase – Fixed Plant Noise
9.70
Provided
that the fixed plants are properly designed to meet the maximum allowable SWL
listed in Table 9.11 – 9.15, there
would not be any residual impacts predicted.
Notwithstanding this, it is
recommended that the following noise reduction measures should be
considered as far as practicable during detailed design:
·
Choose quieter plant
such as those which have been effectively silenced.
·
Include noise
levels specification when ordering new plant (including chillier and E/M
equipment).
·
Locate fixed
plant/louvres away from any NSRs as far as
practicable.
·
Locate fixed plant
in walled plant rooms or in specially designed enclosures.
·
Locate noisy
machines in a basement or a completely separate building.
·
Install direct
noise mitigation measures including silencers, acoustic louvres
and acoustic enclosure where necessary.
·
Develop and implement
a regularly scheduled plant maintenance programme so that equipment is properly
operated and serviced in order to maintain controlled level of noise. The programme should be implemented by
properly trained personnel.
Evaluation of Residual Impacts
Residual Construction Noise Impact of the Project
9.71
With the implementation of the recommended
mitigation measures, the construction noise levels due to the Project at all
representative NSRs would comply with the noise standards stipulated in the
EIAO-TM.
Cumulative Residual Construction Noise Impact
9.72
The potential
cumulative noise impact from the Project and WDII and CWB projects would result
in residual impacts of 1 dB(A) at NSR EX1, Block
A, Causeway Centre.
The construction activities contributed to the residual impact at this
affected NSR is summarized in Table 9.21.
Table 9.21 Cumulative
Residual Construction Noise Impact
|
NSR |
Residual
Impact Exceedance(1) (dB(A)) |
Duration
of Residual Impact (months) |
Number
of Affected Dwellings |
Construction
Activity Causing Exceedance |
|
EX1 |
1 |
2 (Jun – Jul 2014) |
About 120 |
Superstructure works for Phase
1 structure, piling works for Phase 2
structure and demolition and temporary
re-provision of grandstand |
Note:
(1) Daytime construction noise
criterion of 75dB(A) for domestic premises
9.73
The construction
noise impact induced by the Project at NSR EX1 has been minimized as far as
practicable with the implementation
of the recommended mitigation measures including adoption of quieter
plant, movable noise barrier and noise insulating fabric. All feasible
mitigation measures have been exhausted to minimise the residual noise impact
on this NSR.
9.74
It is estimated that minimal size of the community
would be affected by the cumulative impact from construction of the Project and
WDII and CWB projects. Residual cumulative noise impact from construction of the Project
and WDII and CWB projects would result in marginal
exceedance of EIAO-TM daytime noise criterion of 1
dB(A) for a short duration of a total of 2 months.
9.75
The magnitude of
the residual impacts has been assessed in accordance with Section 4.4.3 of the
EIAO-TM and are presented in Table 9.22 below:
Table 9.22 Assessment
of Residual Impacts from Construction Noise
9.76
In view of the
factors considered in Table 9.22, the residual cumulative noise impact would not be significant and
considered as minor and acceptable.
Nevertheless, good site practices
mentioned in Section 9.55 shall be adopted by the Contractors to further ameliorate the noise impact.
Operation Phase – Fixed Plant Noise
9.77
No adverse operational residual noise impact
is envisaged if the noise emissions from the proposed fixed plants are properly
designed to meet the maximum allowable SWL with appropriate noise reduction
measures in place.
Environmental
Monitoring and Audit Requirements
Construction Phase
9.78
An Environmental Monitoring and Audit
programme is recommended to be established according to the predicted
occurrence of noisy activities. The recommended mitigation measures should be
implemented during construction stage. Details of the programme are provided in
a stand-alone EM&A Manual.
9.79
The assessment has indicated that the noise
from the proposed fixed plant noise sources would comply with the EIAO-TM noise
criteria if the noise emissions from the proposed fixed plants are properly
designed to meet the recommended maximum allowable SWL. No specific monitoring for the fixed plant
operation is deemed necessary. As part
of the design process, however, monitoring of operation noise from proposed
fixed plants by the Contractor during the testing and commissioning stage would
be recommended to check the compliance of the noise emission from the operation
of the fixed plant with the noise criteria.
9.80
Noise
arising from the construction activities of the project would have unavoidable
potential impact on the NSRs located in the vicinity of the works areas. Unmitigated construction noise levels at the
representative NSRs are predicted, which are found to be in the range of 52 to 87 dB(A), exceeding the EIAO-TM daytime construction noise
limit by up to 12 dB(A).
9.81
Mitigation
measures including good site practices, quieter plant, movable noise barriers
and noise insulating fabric are recommended to reduce the noise levels to
within the EIAO-TM noise criterion. With
the recommended mitigation measures in place, noise levels at all
representative NSRs are predicted to fully comply with the EIAO-TM daytime
construction noise criterion.
9.82
Several
concurrent projects would be conducted in the vicinity of the Project,
including SCL (MKK-HUH), SCL (TAW-HUH), WDII and CWB projects. Mitigated cumulative construction noise
levels at the representative NSRs are predicted and residual cumulative noise impact
of 1 dB(A) for a short duration of non-persistent 2
months were found at NSR EX1. All
practical mitigation measures have been exhausted to alleviate the construction
noise impact from the Project at EXH 1. The residual cumulative noise impact would not be significant
and considered as minor and acceptable. Good site practices shall be adopted by the Contractors to
further ameliorate the noise impact.
Operation Phase – Fixed Plant Noise
9.83
The
maximum sound power levels allowed to be emitted from fixed plant noise sources
including cooling towers, transformer bay and louvers of ventilation buildings,
ventilation shafts and plant buildings.
With the proper selection of plant and adoption of acoustic treatment,
adverse noise impact from the operation of ventilation buildings, ventilation
shafts and associated plant buildings of the Project would not be anticipated.
9.84
If there is any change in engineering design
information during detailed design stage or fitting-out stage, the fixed source
noise design should be reviewed by engineer/contractor to ensure the NCO and
EIAO criteria could be met in the future.