4.1.1.1 This
section presents the assessment on potential noise impacts arising from
construction and operation of the Project, which has been conducted in
accordance with the criteria and guidelines as stated in Annexes 5 and 13 of
the Technical Memorandum on Environmental Impact Assessment Process (EIAO-TM)
as well as the requirements given in Clause 3.4.5 and Appendix C of the EIA
Study Brief (No. ESB-319/2019).
4.2.1.2
The NCO, 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:
·
EIAO-TM
·
Technical Memorandum on Noise from Construction
Work other than Percussive Piling (GW-TM)
·
Technical Memorandum on Noise from Construction
Work in Designated Areas (DA-TM)
·
Technical Memorandum for the Assessment of Noise
from Places Other Than Domestic Premises, Public Places or Construction Sites
(IND-TM)
4.2.1.3
The NCO provides the statutory framework
for noise control of construction work, other than percussive piling, using powered
mechanical equipment (PME) between the hours of 1900 and 0700 hours or at any
time on Sundays and general holiday (i.e.
restricted hours). Noise control
on construction activities taking place at other times is subject to the “Noise
Standards for Daytime Construction Activities” in Table 1B of Annex 5 in the EIAO-TM. The criteria are summarised in Table
4.1.
Table 4.1 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.
4.2.1.4
Based on the currently envisaged construction
programme, no work will be required in restricted hours as defined under the
NCO. In case of any construction
activities during restricted hours, it is the contractor’s responsibility to
ensure compliance with the Construction Noise Permit (CNP) and the relevant TMs
under the NCO. 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. Regardless of the results of construction
noise impact assessment in this EIA study, the Noise Control Authority will
process Construction Noise Permit (CNP) application, if necessary, based on the
NCO, the relevant technical memoranda issued under the NCO, and the
contemporary conditions/ situations.
Table
4.2 Area Sensitivity Ratings
|
Type of Area Containing NSR
|
Degree to which NSR is Affected by Influencing Factors
|
|
Not Affected
|
Indirectly Affected
|
Directly Affected
|
|
(i) Rural area, including
country parks or village type developments
|
A
|
B
|
B
|
|
(ii) Low density
residential area consisting of low-rise or isolated high-rise developments
|
A
|
B
|
C
|
|
(iii) Urban area
|
B
|
C
|
C
|
|
(iv) Area other
than those above
|
B
|
B
|
C
|
4.2.1.6
According to the IND-TM, the ANLs
for different Area Sensitivity Ratings during different periods are given in
Table
4.3 below.
Table
4.3 Acceptable Noise Level for Fixed
Noise Sources
|
Time Period
|
Acceptable Noise Level (ANL) for Different Area Sensitivity
Rating (Leq 30min, dB(A))
|
|
ASR A
|
ASR B
|
ASR C
|
|
Day (0700 to 1900 hrs)
|
60
|
65
|
70
|
|
Evening (1900 to 2300 hrs)
|
60
|
65
|
70
|
|
Night (2300 to 0700 hrs)
|
50
|
55
|
60
|
4.2.1.7
The Project site is not rural area, low density
residential area or urban area. Thus,
the NSRs are considered located at (iv) area other than those above according
to Table
4.2. The corresponding ANLs for noise sensitive façade
are listed in Table 4.3.
4.2.1.8 The
assessment area for the fixed plant noise impact assessment is defined by a
distance of 300 m from the boundary of the proposed fixed noise source,
i.e. the mid-stream submersible waterpump near Fo Tan
Village. Areas to the northeast and
northwest to the proposed fixed noise source were dominated by industrial
buildings / areas zoned as “Industrial” (“I”) under the Draft Sha Tin Outline
Zoning Plan (OZP) No. S/ST/35. The
IND-TM has laid down the procedures for determining ASRs for NSRs in proximity
to “industrial” zone i.e. Any NSR shall,
irrespective of Table 1 of IND-TM, be assigned an ASR of “C” if it is within
100m of a zone designated as “Industrial” or “Industrial Estate” on a statutory
Outline Zoning Plan, or an ASR of “B” if it is between 100m and 250m from such
a zone, except in cases where Table 1 of IND-TM indicates an ASR of “C”. Hence, Area Sensitivity Rating (ASR) is
assigned as "C" to 51 Fo Tan Village and
Yuk Wo Court i.e. the representative
noise assessment points for fixed noise sources impact assessment since they
are located within 100m from “Industrial” zone according to the Draft Sha Tin
OZP No. S/ST/35.
4.2.1.9
As stipulated in Annex 5 of the EIAO-TM,
the noise standard for planning purposes for fixed noise source are (a) 5 dB(A)
below the appropriate ANL shown in Table 3 of the IND-TM, or (b)
the prevailing background noise levels (for quiet areas with level 5 dB(A)
below the ANL). In this regard, a noise
survey in the vicinity of the representative NSRs was conducted in July 2022 to
determine the background noise levels.
The survey results were compared with the ANL-5 dB(A) criteria to
determine the noise criteria to be adopted in this EIA Report. Locations of noise measurement points and
measured background noise levels, as well as the assessment criteria for the
proposed fixed noise sources of the Project, as adopted in this EIA Report, are
presented in Appendix
4.1.
4.2.1.10
In any event, the Area Sensitivity Ratings
assumed in this EIA Report are for indicative assessment only. It should be noted that fixed noise sources
are controlled under Section 13 of the NCO. At the time of investigation, the Noise Control
Authority shall determine noise impact from concerned fixed noise sources on
the basis of prevailing legislation and practices being in force, and taking
account of contemporary conditions / situation of adjoining land uses. Nothing in this EIA Report shall bind the
Noise Control Authority in the context of law enforcement against all the fixed
noise sources being assessed.
4.3
Description
of Environment
4.3.1.1
The Project site located at the existing Fo Tan Nullah. The upper portion of the Project site is
surrounded by industrial buildings while residential, educational institution,
and government, institution or community (G/IC) developments are located in the
vicinity of lower portion of the site.
Referring to the findings of the site visit, the existing dominant noise
source in the assessment area is traffic noise from Fo Tan Road, Tai Po Road (Shatin) and Sha Tin
Road. Industrial fixed plant
noise in the study area is insignificant.
4.4.1.1
In accordance with Clause 3.4.5.2 of the EIA Study Brief (No.
ESB-319/2019), the construction noise assessment area is defined by a distance
of 300 m from the boundary of the Project whilst the fixed noise source
assessment area is defined by a distance of 300 m from the boundary of the
proposed fixed plant as illustrated in Figure
4.1.
4.4.1.2 Based
on the finding of the site visit and review of latest information including
topographic maps, OZPs (such as the Draft Sha Tin OZP No. S/ST/35) and other
published plans in the vicinity of the Project site, representative noise
sensitive receivers (NSRs) within 300m area from Project boundary have been
identified and are summarised in Table
4.4.
Locations of the representative NSRs are shown in Figure
4.1 and the photographs of selected
representative NSRs which were identified as representative Noise Assessment
Points as detailed in Section
4.4.1.3, are provided in Appendix
4.2.
Table 4.4 Representative Noise Sensitive
Receivers
|
NSR ID
|
Description
|
Land Use
|
Number
of Storeys
|
Approximate
Horizontal Distance from the Nearest Boundary (m)
|
|
Project
Site
|
Proposed
Water Pump
|
|
Existing Noise Sensitive Receivers
|
|
N1
|
Kwai Tei New Village
|
Residential
|
3
|
38
|
>300
|
|
N2
|
Kwai Tei Village
|
Residential
|
3
|
122
|
>300
|
|
N3
|
Chun Yeung Estate
|
Residential
|
34-39
|
9
|
>300
|
|
N4
|
Village House
|
Residential
|
1
|
27
|
>300
|
|
N5
|
The Grandville
|
Residential
|
22
|
217
|
>300
|
|
N6
|
Pat Tsz Wo Village
|
Residential
|
3
|
230
|
280
|
|
N7
|
Wo Liu Hang
|
Residential
|
3-4
|
180
|
212
|
|
N8
|
Yuk
Wo Court
|
Residential
|
47
|
37
|
79
|
|
N9a
|
57 Fo Tan Village
|
Residential
|
1-3
|
5
|
97
|
|
N9b
|
51 Fo Tan Village
|
Residential
|
1-3
|
8
|
17
|
|
N10
|
P.L.K. Siu Hon Sum Primary School
|
Educational
Institution
|
6
|
194
|
254
|
|
N11
|
The Palazzo
|
Residential
|
40-42
|
68
|
>300
|
|
N12
|
Jockey Club TI-I College
|
Educational
Institution
|
5-6
|
46
|
>300
|
|
N13
|
Hong Kong Jockey Club Shatin Staff Quarters
|
Residential
|
20
|
75
|
>300
|
|
N14
|
Hong Kong Sports Institute
|
Educational
Institution
|
<11
|
20
|
>300
|
|
N15
|
Hong Kong Institute of Vocational Education (Shatin)
|
Educational Institution
|
6
|
204
|
>300
|
|
N16
|
City One Shatin
|
Residential
|
27-34
|
236
|
>300
|
|
Planned Noise Sensitive Receivers
|
|
NP1
|
Planned Primary School at No. 1-11 Au Pui Wan Street,
Fo Tan
|
Educational Institution
|
-
|
70
|
152
|
|
NP2
|
Planned Residential Developments at No. 1-11 Au Pui
Wan Street, Fo Tan
|
Residential
|
39-41
|
18
|
144
|
Construction Noise Impact
Table 4.5 Identified Representative
Noise Assessment Points for Construction Noise Impact Assessment
|
NAP ID
|
Description
|
Land Use
|
Number
of Storeys
|
Location
of Selected Assessment Point
|
Approximate
Horizontal Distance from the Nearest Project Site Boundary (m)
|
Daytime
Noise Criterion
(Leq,
30 mins, dB(A))
[1]
|
|
NAP1
|
Chun Yat House, Chun Yeung Estate
|
Residential
|
36
|
G/F
|
13
|
75
|
|
NAP2
|
Yuk
Wo Court
|
Residential
|
47
|
G/F
|
37
|
75
|
|
NAP3
|
51 Fo Tan Village
|
Residential
|
2
|
G/F
|
8
|
75
|
|
NAP4
|
57 Fo Tan Village
|
Residential
|
3
|
G/F
|
5
|
75
|
|
NAP5
|
Tower 1, The Palazzo
|
Residential
|
40
|
G/F
|
68
|
75
|
|
NAP6
|
Jockey Club TI-I College
|
Educational
Institution
|
5-6
|
G/F
|
46
|
70/65
|
Note:
[1] The construction noise criteria for educational
institutions are 70 dB(A) during daytime and 65 dB(A) during examinations
respectively, on any day not being a Sunday or general holiday.
Operation Noise Impact
4.4.1.4
The first layer of NSRs would provide acoustic
shielding to those receivers at further distance behind. The predicted noise levels at the first layer
of NSRs which rely on opened windows for ventilation represent the worst-case
scenario, and therefore representative NAPs at these NSRs were selected for
fixed noise sources impact assessment.
The identified representative NAPs are summarised in Table
4.6 and their locations are shown in Figure 4.2.
Table 4.6 Identified Representative
Noise Assessment Points for Fixed Noise Sources Impact Assessment
|
NAP ID
|
Description
|
Land Use
|
Number
of Storeys
|
Location
of Selected Assessment Point
|
Approximate
Horizontal Distance from the Proposed Water Pump (m)
|
Daytime
& Evening Noise Criteria, dB(A) [1]
|
|
NAP2
|
Yuk
Wo Court
|
Residential
|
47
|
G/F
|
79
|
59
|
|
NAP3
|
51 Fo Tan Village
|
Residential
|
2
|
G/F
|
17
|
60
|
Note:
[1] The proposed water pump would not
operate during night-time (2300 – 0700 hours).
Daytime / Evening criterion is therefore adopted.
(A)
Channel bed modification
(B)
Improvement of existing walkways such as
construction of viewing deck/pavilion, renovation of existing footbridges
(C)
Construction of dry weather flow interceptor
(DWFI) system along the nullah and associated connection works to existing
sewerage system (for Section 2 to Section 6) & submersible water pumps
installed under the nullah bed at mid-stream of FTN and pipes along the nullah
for ecological enhancement associated water supplement (for Section 3 to
Section 6)
(D)
Landscape works along nullah bank and utility
works
(E)
Construction of underground water storage tank
(F)
Desilting at downstream tidal zone
4.5.1.2 The
tentative construction programme, locations of the works of the Project as
defined in the EIA and plant inventory provided by the Project Engineer for the
construction noise impact assessment are presented in Appendix
2.2, Appendix
4.2 and
Appendix 4.3 respectively. The feasibility and practicability of the
plants adopted and their details for the assessment have been confirmed by the
Project Engineer. Referring to
construction programme, the Project site would be divided into six work
sections, Section 1 to Section 6. The
construction tasks (A) to (D) would be undertaken on almost all work sections
and completed before commencement of the similar construction tasks at another
work section. The desilting works at
downstream tidal zone (Task F) would be carried out at Work Section 1
only. The underground water storage tank
would only be constructed (Task E) at Work Section 6. Therefore, the area of active work site is
limited.
4.5.1.3 Potential
source of noise impact arising from the construction of the Project would be
the use of PME for various construction activities. No marine transportation of construction
materials and waste is required. Based
on the currently envisaged construction programme, works using PME during
restricted hours (i.e. the hours from
1900 to 0700 hours or at any time on a general holiday) or percussive piling
works would not be required. Excavation
and lateral support (ELS) which would involve sheet-piling works would be
required for two construction activities “Connection
Work to the Existing Sewerage System” at Work Section 2 and “Construction of
Underground Water Storage Tank” at Work Section 6. The PME required for sheet-piling has been
included in the plant inventory for the construction noise impact assessment. Only impacts from daytime general
construction activities have been assessed in this EIA Report. As only limited piling works would be
involved in construction phase of the Project, potential ground-borne
construction noise impact would not be anticipated.
4.5.1.4
Referring to Table 2.2,
the planned flood walls along Shing Mun River Channel under “Drainage
Improvement Works in Sha Tin and Sai Kung” project and the footprint of the
planned sewage rising main under “Relocation of Sha Tin Sewage Treatment Works
to Caverns – Upstream Sewerage and Pumping Stations” project, development of
“New Facilities Building of the Hong Kong Sports Institute (HKSI)” as well as
“Redevelopment of Sui Fai Factory Estate for Residential Use” would be located
within 300m assessment area of this Project.
Representative NSR NAP6 is located within 300m assessment of these two
DSD projects and the development of new facilities building of the HKSI while
NSR NAP2, NAP3 and NAP4 are located within 300m assessment of the Redevelopment
of Sui Fai Factory Estate project.
Potential cumulative construction noise may be anticipated at these
NSRs.
4.5.2
Operational Phase
4.6
Assessment
Methodology
4.6.1.1 The
methodology for the construction noise impact assessment follows the procedures
outlined in the GW-TM. The
general approach is summarised below:
·
Identify representative NSRs which would most
likely be affected by the noise from the construction work;
·
Determine the items of PME for each discrete
construction activity, based on available information or agreed plant
inventories;
·
Assign sound power levels (SWLs) to the proposed
PME according to the GW-TM or other
sources;
·
Calculate distance attenuation and screening
effects to NSRs from notional noise source;
·
Predict construction noise levels at NSRs in the
absence of any mitigation measures;
·
Consider cumulative impact from concurrent
projects within 300 m of the NSRs, if any; and
·
Compare the cumulative construction noise level
against the corresponding noise criterion and propose suitable mitigation
measures where necessary.
4.6.1.2 The
assessment of construction noise was undertaken based on standard acoustic
principles. SWLs of equipment were taken
from Table 3 of the GW-TM and “Sound power levels of other commonly
used PME” issued by EPD. Where no
relevant SWL can be found in the GW-TM and other PME, reference is made
to the information relating to Quality Powered Mechanical Equipment (QPME)
available at EPD’s website or PME specification published by equipment
manufacturer. Groups of PME were
assigned for various construction activities of the proposed Project. The Project Proponent has confirmed that the
proposed plant inventories as being practical and adequate for completing the
works within the scheduled timeframe.
4.6.1.3 The
assessment was undertaken based on the assumption that all items of
construction equipment would be located at a notional noise source point or
probable source position where specific activity is to be performed. Referring to the preliminary engineering
design, under each main construction task, only one sub-plant / sub-group in a
construction task will be operating at the same time. The
sound pressure level (SPL) of each construction task has been calculated,
depending on the number of plant items involved, utilisation rate and the
distance from the NSR. A positive
3 dB(A) façade correction has been added to the predicted noise levels to
account for the façade effect at each assessment point. The noise levels at the NSRs have then been
predicted by adding up the SPLs of all concurrent construction tasks from the
Project and other concurrent projects identified during the EIA study within
the 300m assessment area.
4.6.1.4 The
unmitigated construction noise impacts at the identified NSRs have been
predicted accordingly. Practicable
direct noise mitigation measures including the use of quieter equipment,
movable noise barriers and quieter alternative methods have been considered if
exceedance of relevant noise standards is predicted. Appropriate correction factors for barrier
effect have been adopted in accordance with Section 2.10 of the GW-TM. In cases where the mitigated noise levels
still exceed the relevant criteria, the duration of noise exceedance would be
estimated.
4.6.2.1
During operational phase, fixed plant noise
impact would arise from the operation of the proposed submersible water pumps
installed under the nullah bed at mid-stream of FTN. The fixed plant noise impact was assessed in
accordance with the IND-TM. The
distance attenuation was estimated using the standard acoustic equation and a
positive 3 dB(A) façade correction was added to the predicted noise levels to
account for the façade effect at each noise assessment point.
4.6.2.2
Based on the current design information, the
proposed submersible water pumps would be housed in an underground valve
chamber and wet well below the nullah bed.
All on-duty equipment would not operate during night-time (i.e. 2300 – 0700 hours). The SWL of the fixed plants were referenced
to engineering design information and manufacture’s catalogue of plants of
equivalent / similar specifications. The
fixed plant / equipment inventory of the design at the time of preparation of
this EIA is presented in Appendix
4.5. The equipment inventory has been confirmed
with the Project Engineer. The noise
performance of the proposed fixed plants would be reviewed during detailed
design stage with due regard to the characteristics of tonality, impulsiveness
and intermittency. If the noise exhibits
characteristics of tonality, intermittency or impulsiveness during the detailed
design or the commissioning of the plant, the SWL should be reduced in accordance
with the recommendation given in Section 3.3 of IND-TM to ensure
noise compliance at the NSRs.
4.6.2.3
As the submersible pumps would be housed inside
underground valve chamber and wet well below the nullah bed, a noise reduction
of 20 dB(A) was applied to the noise levels generated by the equipment.
4.7.1.1 Under
unmitigated scenario, exceedances of the construction noise criteria for
residential uses and educational institution during daytime would be
predicted. Details of the unmitigated
construction noise assessment are presented in Appendix
4.4 with the results summarised in Table 4.7.
Table 4.7 Summary
of Unmitigated Construction Noise Levels
|
NAP ID
|
Description
|
Daytime Noise Criterion,
(Leq, 30 mins, dB(A))
|
Predicted Unmitigated Maximum Construction Noise Levels,
(Leq, 30 mins, dB(A))
|
Max. Noise Exceedance, (dB(A))
|
|
NAP1
|
Chun Yat House, Chun Yeung Estate
|
75
|
77
|
2
|
|
NAP2
|
Yuk
Wo Court
|
75
|
74
|
-
|
|
NAP3
|
51 Fo Tan Village
|
75
|
91
|
16
|
|
NAP4
|
57 Fo Tan Village
|
75
|
95
|
20
|
|
NAP5
|
Tower 1, The Palazzo
|
75
|
71
|
-
|
|
NAP6
|
Jockey Club TI-I College
|
70
(65 during examination)
|
76
|
6 (11 during examination)
|
4.7.1.2
The unmitigated maximum construction noise
levels at the identified representative NSRs would range from 71 – 95
dB(A). NAP1, NAP3, NAP4 and NAP6 would
exceed the EIAO-TM daytime construction noise criteria.
Mitigation measures are therefore required to alleviate the adverse
construction noise impact from this Project.
4.7.1.3
The total number of dwellings, classrooms and
other noise sensitive receivers that would be exposed to noise impacts
exceeding the criteria set in Annex 5 in the EIAO-TM were evaluated and it is
estimated that a total of about 220 dwellings and 30 classrooms will be exposed
to construction noise impact exceeding the criteria set in Annex 5 in the
EIAO-TM under unmitigated scenario.
4.7.2
Operational Phase
4.7.2.1
The fixed plant noise levels from the normal
operation of the proposed submersible water pumps installed under the nullah bed
at mid-stream of FTN were predicted by adopting the methodology in Section 4.6.2. The predicted fixed plant noise levels under
unmitigated scenario are summarised in Table
4.8 with details of
the calculations given in Appendix
4.5.
Table 4.8 Summary of Predicted Fixed Plant Noise Levels
without Mitigation Measures
|
NAP
ID
|
Description
|
Daytime /
Evening Criterion, dB(A)
|
Predicted
Fixed Plant Noise Level,
Leq
30-min dB(A)
|
|
NAP2
|
Yuk Wo Court
|
59
|
22
|
|
NAP3
|
51 Fo Tan Village
|
60
|
34
|
4.8.1
Construction Phase
4.8.1.1 The
results of the construction noise assessment indicate that there would be
exceedance of the construction noise criteria at most of NAPs in the absence of
any mitigation measures. The various
mitigation options listed below have thus been considered:
·
Good site practices;
·
Use of quality powered mechanical equipment
(QPME) / quieter construction method; and
·
Adoption of movable noise barriers
Good Site
Practices
4.8.1.2 Although
the noise mitigation effects are not easily quantifiable, and the benefits may
vary with site conditions and operating conditions, good site practices are
easy to implement and do not impact upon the works schedule. The site practices listed below should be
followed during construction works:
·
Only well-maintained PME to be operated on-site
and should be serviced regularly during construction works;
·
Silencers or mufflers on construction equipment should
be utilised (if appropriate) and should be properly maintained during
construction;
·
Mobile plant, if any, should be sited as far
away from NSRs as possible;
·
Machines and plant (such as trucks) that may be
in intermittent use should be shut down between work periods or should be
throttled down to a minimum;
·
Plant known to emit noise strongly in one
direction should, wherever possible, be orientated to direct noise away from
the nearby NSRs; and
·
Material stockpiles and other structures should
be effectively utilised, wherever practicable, in screening noise from on-site
construction activities.
Use of
QPME / Quieter Construction Method
4.8.1.3 The
use of QPME is considered a practicable means to mitigate the construction
noise impact. QPME is defined as a PME
having actual SWL lower than the value specified in the GW-TM. The type of QPME adopted in this assessment
is for reference only. The contractors may adopt alternative
QPME as long as it can be demonstrated that they would not result in
construction noise impacts worse than those predicted in this assessment.
4.8.1.4 Quieter
construction method such as silent piling by press-in method is adopted as an
alternative of traditional sheet piling.
A sheet pile is clipped and pressed under the ground. Noise can be minimised by press-in sheet
piles with drilling simultaneously for piling works at harder ground. The noise impact can also be further reduced
as the piling works can be completed within the shorter duration by using this
method.
4.8.1.5 For
the use of QPME / quieter construction method associated with the construction
works, reference has been made to QPME list available on the EPD website, which
provides the SWLs for specific QPME or PME specification published by equipment
manufacturer. The SWLs of QPME adopted
for the assessment are listed in Table 4.9.
Table 4.9 SWL of Quiet PME
Adopted for Construction Noise Mitigation
|
Plant / Equipment
|
Ref Code
|
SWL, dB(A)
|
|
Hand-held Percussive
Breaker
|
EPD-04329
|
99
|
|
Excavator/loader,
wheeled/tracked
|
EPD-09127
|
99
|
|
Roller, vibratory
|
EPD-10387
|
94
|
|
Crane,
mobile/barge mounted (diesel)
|
EPD-08825
|
101
|
|
Giken Piler and Power-pack
|
-
|
94[1]
|
|
Crane, mobile/barge
mounted (diesel)
|
EPD-05602
|
91
|
Note:
[1] The SWL is reference to the approved EIA
report "Tsim Sha Tsui
Station Northern Subway" (AEIAR-127/2008).
For the sound pressure level at 7 m from equipment, see website link
below.. https://www.epd.gov.hk/epd/misc/construction_noise/contents/index.php/en/home2/quieter-construction-equipment/item/27-press-in-method.html
Use of
Movable Noise Barriers
4.8.1.6 Movable
noise barriers that can be placed close to the construction equipment and moved
along with the PME are effective for screening noise from NSRs. A typical design which has been used locally
is a wooden framed barrier with a cantilevered upper portion of superficial
density no less than 10 kg/m² on a skid footing with internal sound absorptive
lining. This measure is particularly
effective for low level zone of NSRs. A
longer cantilevered top cover would be required to achieve screening benefits
at upper floors of NSRs. The Contractor
shall be responsible for the design and actual position of the movable noise
barriers with due consideration given to the position and size of the PME, and
the requirement of intercepting the line-of-sight from the NSRs to the PME, as
well as ensuring that the barriers should have no opening and gap. It is anticipated that properly designed
noise barriers would achieve a 5 dB(A) reduction for mobile PME and a 10 dB(A)
reduction for static PME.
Mitigated Construction Noise Levels
4.8.1.8 Having
taken into account the noise reduction achieved by the above-mentioned
mitigation measures, the mitigated maximum construction noise levels at all the
representative NAPs would comply with the EIAO-TM daytime construction noise criteria, except NAP4. The predicted noise impacts at the NAPs are
summarised in Table
4.10 and the detailed calculations are provided
in Appendix 4.7.
Table 4.10 Summary
of Mitigated Construction Noise Levels
|
NAP
ID
|
Description
|
Daytime Noise
Criterion,
(Leq, 30 mins,
dB(A))
|
Predicted Mitigated Maximum
Construction Noise Levels,
(Leq, 30 mins,
dB(A))
|
Predicted Mitigated
Maximum Construction Noise Levels, After Additional Mitigation Measure,
(Leq, 30 mins,
dB(A))
|
|
NAP1
|
Chun
Yat House, Chun Yeung Estate
|
75
|
71
|
NA
|
|
NAP2
|
Yuk Wo
Court
|
75
|
64
|
NA
|
|
NAP3
|
51 Fo Tan Village
|
75
|
73
|
NA
|
|
NAP4
|
57 Fo
Tan Village
|
75
|
76
|
75
|
|
NAP5
|
Tower
1, The Palazzo
|
75
|
59
|
NA
|
|
NAP6
|
Jockey
Club TI-I College
|
70 (65 during examination)
|
63
|
NA
|
4.8.1.9 Based
on the results in Appendix 4.7, the noise exceedance of 1 dB(A) predicted
at NAP4 would be limited to July and August 2026 due to the construction of
viewing deck / pavilion, renovation of existing footbridges at Work Section 3. To further mitigate the noise impact, it is
proposed that the breaker and the roller should not be operated or in use
concurrently. With the implementation of
this additional mitigation measure, the predicted noise levels at NAP4 would
comply with the EIAO-TM daytime construction noise
criterion as summarised in Table 4.10. The
detailed calculation with the implementation of this additional noise
mitigation measure for NAP4 is presented in Appendix
4.8.
4.8.1.10 The
results revealed that the construction noise levels from this Project at all
NSRs would comply with the EIAO-TM daytime construction noise criteria after the implementation of the
proposed noise mitigation measures. No
adverse impact would be anticipated at any existing and planned/committed NSRs
within 300m from the Project works area.
Cumulative Construction Noise Impact from Concurrent Projects within
300m Assessment Area
4.8.1.11
As mentioned in Section
4.5.1.4, potential cumulative
construction noise from two DSD projects and the development of new facilities
building of the HKSI may be anticipated at NSR NAP6. Referring to the assessment results presented
in Appendix
4.7, the predicted
mitigated construction noise levels contributed from this Project at NSR NAP6
would be over 60 dB(A) during January – September 2024. For other construction periods, the mitigated
construction noise impact from this Project is 10 dB(A) less than the daytime
construction noise criterion of NAP6 during normal teaching period, cumulative
noise impact is anticipated to be insignificant. There is no confirmed detailed construction
programme of these two DSD projects and the development of new facilities
building of the HKSI at the time of the assessment. Heavy construction activities would not be
anticipated from flood wall or sewage rising mains construction from the two
DSD projects that cumulative noise impact is anticipated to be
insignificant. Nonetheless, as advised
by DSD, they would request the contractors of these two DSD projects to arrange
the noisy construction activities to avoid overlapping with the construction
activities of this Project undertaken at Work Section 1 and 2 of FTN (which are
close to the Project boundaries of the two DSD projects) to further minimise
the potential cumulative construction noise impact during January – September
2024 and examination period of NAP6.
These requirements shall be stated in the contracts of these two DSD
projects. With this control measure in
place, no adverse cumulative construction noise impact from these DSD projects
would be anticipated. Likewise, the
planned building of the HKSI is targeted for completion in mid-2024, which
would be overlapped with the Project for less than one year. Since the main works of this building
development project would be expected to be at its final stage of construction
during the overlapping period, heavy construction activities would not be
anticipated and cumulative noise impact is anticipated to be insignificant.
4.8.1.12
Three representative NSRs NAP2 NAP3 and NAP4 are
located from the site boundary of redevelopment of Sui Fai Industrial Building
at 152m, 52m and 125m, respectively. The
detailed construction programme and plant inventory for this redevelopment
project are not available at the time of this EIA Study. Assuming that the construction noise impact
from this redevelopment project at its nearest NSR, 24C Fo
Tan Village which is about 15m from the Sui Fai Industrial Building site
boundary would comply with the noise criterion of 75dB(A), the predicted noise
levels due to this redevelopment project at NSR NAP2, NAP3 and NAP4 would be 55
dB(A), 64 dB(A) and 57 dB(A), respectively.
Taking into account the cumulative noise levels from this Project as
presented in Table 4.10, the predicted
cumulative noise levels at NSR NAP2, NAP3 and NAP4 would be 65 dB(A), 74 dB(A)
and 75 dB(A), complying with the EIAO-TM daytime construction noise criterion
of 75 dB(A).
4.8.1.13 With
the implementation of the above recommended mitigation measures, including adoption
of good site practices, use of quality PME / quieter construction method (silent piling by press-in method), adoption of
movable noise barriers, and proper scheduling of noisy
construction activities, the mitigated cumulative construction noise levels
from the Project and nearby concurrent project at all representative NSRs would
fulfil relevant noise control standards stipulated under Annex 5 of
EIAO-TM. Subject to the detailed design
and construction programme, as an enhaccement measure
to further improve the environmental performance of the construction of the
Project, other quieter construction methods, such as use of road ripper instead
of breaker for concrete breaking during excavation works, would be considered
where viable.
4.8.1.14
A construction noise management plan, which to
verify the inventory of noise sources, and to assess the effectiveness and
practicality of all identified measures for mitigating the construction noise
impact of the project, would be prepared before commencement of construction
works.
4.8.2
Operational Phase
4.8.2.1
As shown in Table 4.8,
all the predicted fixed plant noise levels at the representative NSRs would
comply with the fixed plant noise criteria.
Nonetheless, the following best practices should be implemented as far
as practicable to further minimise any potential impacts:
·
Quieter plant should be chosen as far as
practicable;
·
Include noise levels specification when ordering
new plant items;
·
Develop and implement a regularly scheduled
plant maintenance programme so that plant items are properly operated and
serviced. The programme should be
implemented by properly trained personnel.
4.9.1
Construction Phase
4.9.1.1 With
the implementation of the recommended noise mitigation measures, construction
noise levels at all representative NSRs would comply with EIAO-TM
daytime construction noise criteria. No
residual construction noise impact is anticipated.
4.9.2
Operational Phase
4.9.2.1 No
residual noise impact is anticipated during the operational phase of the
Project.