4.1.1.1
This
section presents an assessment of potential noise impacts associated with the
construction and operation of the Project.
The noise impact assessment has been conducted in accordance with the
requirements of Annex 5 and Annex 13 of the Technical Memorandum on
Environmental Impact Assessment Process (EIAO-TM) as well as the requirements
set out under Clause 3.4.5 of the Environmental Impact Assessment (EIA) Study
Brief (No. ESB-313/2019) (hereinafter “the Study Brief”).
4.2.1
General
4.2.1.1
Noise impact has been assessed in accordance with the criteria and methodology given
in the EIAO-TM and the Technical Memoranda (TM) under the Noise Control
Ordinance (NCO).
(i)
Technical
Memorandum for the Assessment of Noise from Places other than Domestic
Premises, Public Places or Construction Sites (IND-TM);
(ii)
Technical
Memorandum on Noise from Construction Work in Designated Areas (DA-TM);
(iii) Technical Memorandum on Noise from Construction
Work other than Percussive Piling (GW-TM); and
(iv) Technical Memorandum on Noise from Percussive
Piling (PP-TM).
4.2.1.3
With
regard to the assessments of the construction noise impact during restricted
hours (on all days during 1900 and 0700 hours and at any time on Sundays and
public holidays) and operational fixed noise sources impact, the NCO designates
acceptable noise levels for Noise Sensitive Receivers (NSRs) on the basis of an
Area Sensitivity Rating (ASR), based on the type of area containing the NSR (see
Table 4.1). Within these areas, the
presence of "influencing factors" (such as the presence of industrial
area or major roads) can further affect the ASR and hence the acceptable noise
levels.
Table 4.1 Area Sensitivity Ratings (ASRs)
|
Type of Area Containing NSR
|
Degree
to which NSR is affected by Influencing Factor
|
|
Not
Affected
|
Indirectly
Affected
|
Directly
Affected
|
|
Rural area,
including country parks or village type developments
|
A
|
B
|
B
|
|
Low density
residential area consisting of low-rise or isolated high-rise developments
|
A
|
B
|
C
|
|
Urban area
|
B
|
C
|
C
|
|
Area other than
those above
|
B
|
B
|
C
|
Notes:
·
“country park” means an area that is designated
as a country park pursuant to section 14 of the Country Parks Ordinance;
·
“directly affected" means that the NSR is
at such a location that noise generated by the IF is readily noticeable at the
NSR and is a dominant feature of the noise climate of the NSR;
·
"indirectly affected" means that the
NSR is at such a location that noise generated by the IF, whilst noticeable at
the NSR, is not a dominant feature of the noise climate of the NSR;
·
"not affected" means that the NSR is
at such a location that noise generated by the IF is not noticeable at the NSR;
and
·
"urban area" means an area of high
density, diverse development including a mixture of such elements as industrial
activities, major trade or commercial activities and residential premises.
Construction
Works during Non-restricted Hours
Table 4.2 Noise Criteria for
Construction Noise during Non-Restricted Hours
|
|
|
|
Domestic
premises
|
75
|
|
Educational
Institution
|
70
|
|
Educational
Institution (during examination)
|
65
|
·
Non-restricted hours are 0700 to1900 hours on
any day not being a Sunday or general holiday.
·
The above standards apply to uses which rely on
opened windows for ventilation.
·
The above standards shall be viewed as the
maximum permissible noise levels assessed at 1m from the external façade.
Construction Works during Restricted Hours
4.2.2.2
During
restricted hours (i.e. on all days during 1900 and 0700 hours and at any time
on Sundays and general holidays), the use of PME for the purpose of carrying
out construction works is prohibited unless a Construction Noise Permit (CNP)
has been obtained. A CNP may be granted in
cases where the noise can be contained within the Acceptable Noise Level (ANL)
for the NSRs. ANLs are assigned
depending upon the ASRs. The
corresponding ANLs for construction work other than percussive piling
during restricted hours are given in Table 4.3.
Table 4.3 Acceptable Noise Levels under GW-TM
|
Time Period
|
Acceptable
Noise Levels (ANLs), dB(A)
|
|
ASR
A
|
ASR
B
|
ASR
C
|
|
All days during
the evening (1900 to 2300 hours), and general holidays (including Sundays)
during the daytime and evening (0700 to 2300 hours)
|
60
|
65
|
70
|
|
All days during
the night-time (2300 to 0700 hours)
|
45
|
50
|
55
|
4.2.2.3
The
Noise Control Authority will consider a well-justified CNP application, for
construction works within restricted hours as guided by the relevant Technical
Memoranda issued under the Noise Control Ordinance. The Noise Control Authority will take into account
of contemporary conditions / situations of adjoining land uses and any previous
complaints against construction activities at the site before making his
decision in granting a CNP. Nothing in
this EIA shall bind the Noise Control Authority in making his decision. If a CNP is to be issued, the Noise Control
Authority shall include in it any condition he thinks fit. Failure to comply with any such conditions
will lead to cancellation of the CNP and prosecution action under the NCO.
4.2.2.4
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 SPME includes hand-held breaker,
bulldozer, concrete lorry mixer, dump truck and hand-held vibratory poker. The PCW are:
·
Erecting or dismantling of
formwork or scaffolding.
·
Loading,
unloading or handling of rubble, wooden boards, steel bars, wood or scaffolding
material.
·
Hammering.
4.2.2.5
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. These noise
level requirements are more stringent (i.e. 15 dB(A) less than those listed in
the GW-TM) to offer additional protection to the population.
4.2.3.1
Fixed
noise sources impact are controlled by the NCO and IND-TM. The ANLs for the NSRs are determined based on
the ASR as stated in Table 4.1. The
ANLs for different ASRs during different periods are summarised in Table 4.4 below.
Table 4.4 Acceptable Noise Levels for Fixed Noise
|
Time Period
|
ANL,
dB(A)
|
|
ASR
A
|
ASR
B
|
ASR
C
|
|
Day (0700 to
1900 hours)
|
60
|
65
|
70
|
|
Evening (1900 to
2300 hours)
|
60
|
65
|
70
|
|
Night (2300 to
0700 hours)
|
50
|
55
|
60
|
4.2.3.2
According
to the Revised Recommended Outline Development Plan (RODP) of Planning and
Engineering Study for Housing Sites in Yuen Long South (YLS DA), YLSEPP is
located at the southern tip of YLS DA. It
is bound by Ma Shan (Kung Um Shan) and Tai Lam Country Park at its south west.
There will be a planned reedbed and green belt to its north, and planned
government and institutional land use to its east side. YLS DA will be developed as a new town with a
mixture of land uses, which comprised of medium to high-rise residential
developments, schools and governmental reserve, etc. The ASR of the type of area within the NSR
located has been determined for assessment purpose. When determining the ASR for an NSR, the
following are considered:
·
The type of area containing the NSR;
·
The Influencing Factor (IF) identified;
·
The Degree to which the NSR is affected by IF; and
·
If applicable, nearby OZP “Industrial” or “Industrial Estates” zone.
4.2.3.3
There
are two existing residential NSRs identified within the 300m assessment
area. The identified NSRs are located to
the east of the proposed YLSEPP. These
NSRs are 1-storey to 3-storey high village houses. They are located in rural area and are not
affected by any influence factor, an ASR of “A” has been assigned. The planned NSRs are medium-rise residential
developments and schools located within the YLS DA. Thus, they are considered to be located in an
area other than rural, urban or low density residential area and they are not
affected by any influence factor, an ASR of “B” has been assigned.
4.2.3.4
As
stipulated in Annex 5 of the EIAO-TM, the noise standard for planning purpose
for fixed noise source are (a) 5dB(A) below the appropriate ANL shown in Table
2 of the IND-TM or (b) the prevailing background noise levels (for quiet area
with level 5dB(A) below the ANL). In
this regard, noise measurement was undertaken in the vicinity of the
representative NSRs, which having similar typical background noise environment
of the identified, to study the prevailing background noise level. The noise measurement results are presented
in Appendix 4.1. The lesser of the lowest background noise
levels has been compared with the 5dB(A) below the appropriate ANL to obtain
the fixed noise criteria, which listed in below Table
4.5.
Table 4.5 Summary of Prevailing Background Noise Measurement Results
|
Noise Assessment Point
|
Measurement Location ID
|
Lowest
Measured Noise Level,
LA90
30-min, dB(A)(1)
|
|
ID
|
Description
|
Day (2)
|
Evening (3)
|
Night (4)
|
|
YE03
|
121 Wong
Nai Tun Tsuen
|
PSSR
|
49
|
49
|
47
|
|
YE04
|
125 Wong
Nai Tun Tsuen
|
|
YP01
|
Planned
Residential Development (R3.1e)
|
|
YP02
|
Planned
Residential Development (R3.4b)
|
|
YP03
|
Planned
Education Development (E3.3)
|
|
YP04
|
Planned
Education Development (E3.1)
|
|
YP05
|
Planned
Low-rise Residential Development (VR3.1)
|
4.2.3.5
In any
event, the ASR assumed in the EIA Report is for indicative assessment
only. It should be noted that the 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/situations of adjoining land uses. Nothing in the EIA Report shall bind the
Noise Control Authority in the context of law enforcement against all the fixed
noise sources being assessed.
4.3.1.1
The
YLSEPP is located at the southern tip of YLS DA. It is bound by Ma Shan (Kung Um Shan) and Tai
Lam Country Park at its south west. There will be a planned reedbed and green
belt to its north, and planned government and institutional land use to its
east side.
4.3.1.2
The YLS
DA is generally rural in character with a mixture of land uses. The predominant
uses are brownfield operations including open storage yards, warehouses,
industrial workshops, etc. These brownfield operations are intermingled with
rural settlements and residential settlements, agricultural land, livestock
farms and vacant land. The prevailing
noise climate of the assessment area is dominated by the brownfield operations.
4.4.1.1
In
accordance with Annex 13 of the EIAO-TM, domestic premises including temporary
housing, educational institutions (including kindergartens and nurseries),
hospitals, medical clinics, homes for the aged, convalescent homes, places of
public worship, libraries, courts of law, performing arts centres, auditoria
and amphitheatres, and Country Park are noise sensitive receivers (NSRs).
4.4.1.2
The
assessment area for noise impact assessment is defined by a distance of 300m
from the Project boundary as specified in the Study Brief. The NSRs within the assessment area for the
construction and operation noise impact assessments have been identified based
on the finding of the site visits and review of latest information from
Planning Department, and Lands Department as well as the statutory Outline
Zoning Plan (OZP) gazetted under Town Planning Ordinance including OZP Plan No.
S/YL-TT/18 – Tai Tong and Plan No. S/YL-TYST/14 – Tong Yan San Tsuen, Revised
Recommended Outline Development Plan (RODP) for YLS DA and other published
plans in the vicinity of the Project site.
The identified NSRs in the vicinity of the Proposed YLSEPP are listed in
Table
4.6. Locations of these
NSRs are presented in Figure
4.1.
Table 4.6 Identified Noise Sensitive Receivers in the Vicinity of Proposed
YLSEPP
|
NSR ID
|
Description
|
Land
Use
|
Existing / Planned
|
|
PST
|
Pak Sha Tsuen
|
Residential
|
Existing
|
|
WNTT
|
Wong Nai Tun Tsuen
|
Residential
|
Existing
|
|
YLSDA
|
Yuen Long South Development Area
|
Residential
|
Planned
|
|
TLCP
|
Tai Lam Country Park
|
Country Park
|
Existing
|
4.4.1.3
The
first layer of NSRs located close to the subject noise sources are considered
as the most affected location and would provide acoustic shielding to those
receivers at further distance behind.
The first layer of NSRs represent the worst-case scenario and are
selected as representative noise assessment points (NAPs) for the noise
assessment. In accordance with
Annex 13 of the EIAO-TM, country park is also classified as NSRs. However, there would be no noise sensitive
uses in Tai Lam Country Park that rely on opened windows for ventilation. Therefore, noise criteria listed in Annex 5
of EIAO-TM is not applicable to Tai Lam Country Park. The EIAO-TM however does not stipulate
specific noise limits for this type of NSRs.
Given that visitors using hiking trails in the Tai Lam Country Park are
of transient nature, no adverse construction noise impact is anticipated. The identified existing and planned
representative NAPs within 300m assessment area for construction phase and
operation phase are presented in Table
4.7 and Table
4.8 respectively. Locations of the
representative NAPs are shown in Figure 4.1.
Photographs of the existing NSRs are provided in Appendix
4.2.
Table 4.7 Identified Noise Assessment Points in
the Vicinity of Proposed YLSEPP for Construction Noise Impact Assessment
|
NAP ID
|
Description
|
Land
Use
|
No.
of Storeys
|
Shortest
Distance from Project Site Boundary (m)
|
Existing / Planned
|
|
YE01*
|
291 Pak Sha Tsuen
|
Residential
|
3
|
50
|
Existing
|
|
YE02*
|
Pui Hong Kui
|
Residential
|
3
|
120
|
Existing
|
|
YE03
|
121 Wong Nai Tun Tsuen
|
Residential
|
3
|
250
|
Existing
|
|
YE04
|
125 Wong Nai Tun Tsuen
|
Residential
|
3
|
250
|
Existing
|
Note:
* This NAP would be demolished no
later than 2029 under YLSDA Stage 3 in accordance with its latest programme.
Table 4.8 Identified Noise Assessment Points in the Vicinity of Proposed
YLSEPP for Operational Noise Impact Assessment
|
NAP ID
|
Description
|
Land
Use
|
No.
of Storeys
|
Shortest
Distance from Project Site Boundary (m)
|
Existing / Planned
|
|
YE03
|
121 Wong Nai Tun Tsuen
|
Residential
|
3
|
250
|
Existing
|
|
YE04
|
125 Wong Nai Tun Tsuen
|
Residential
|
3
|
250
|
Existing
|
|
YP01
|
YLS DA - Planned Residential Development
(R3.1e)
|
Residential
|
11
|
270
|
Planned
|
|
YP02
|
YLS DA - Planned Residential Development
(R3.4b)
|
Residential
|
14
|
270
|
Planned
|
|
YP03
|
YLS DA - Planned Education Development
(E3.3)
|
Educational
|
8
|
270
|
Planned
|
|
YP04
|
YLS DA - Planned Education Development
(E3.1)
|
Educational
|
8
|
260
|
Planned
|
|
YP05
|
YLS DA - Planned Low-rise Residential
Development (VR3.1)
|
Residential
|
3
|
190
|
Planned
|
4.4.1.4
Based
on the ANLs presented in Table
4.4 and the background noise measurement
results as summarized in Table
4.5, the fixed plant noise criteria of the
representative NSRs have been determined and are presented in Table
4.9.
Table 4.9 Noise Criteria for Fixed Noise Sources Impact Assessment
|
NAP ID
|
ANL – 5,
dB(A)
|
Measured Lowest
Prevailing Background Noise Level (1),
LA90
30-min, dB(A)
|
Noise
Criteria, dB(A)
|
|
Day (2)
|
Evening (3)
|
Night (4)
|
Day (2)
|
Evening (3)
|
Night (4)
|
Day (2)
|
Evening (3)
|
Night (4)
|
|
YE03
|
55
|
55
|
45
|
49
|
49
|
47
|
49
|
49
|
45
|
|
YE04
|
55
|
55
|
45
|
49
|
49
|
47
|
49
|
49
|
45
|
|
YP01
|
60
|
60
|
50
|
49
|
49
|
47
|
49
|
49
|
47
|
|
YP02
|
60
|
60
|
50
|
49
|
49
|
47
|
49
|
49
|
47
|
|
YP03
|
60
|
60
|
50
|
49
|
49
|
47
|
49
|
49
|
47
|
|
YP04
|
60
|
60
|
50
|
49
|
49
|
47
|
49
|
49
|
47
|
|
YP05
|
60
|
60
|
50
|
49
|
49
|
47
|
49
|
49
|
47
|
Notes:
(1)
Façade correction of +3 dB(A) has been added to the measurement results
for free-field measurement.
(2)
Daytime means 07:00 – 19:00.
(3)
Evening time means 19:00 – 23:00.
(4)
Night-time means 23:00 – 07:00 of the next day.
4.5.1
Construction Phase
4.5.1.1
The
Project is to construct a sewage treatment works and effluent discharge pipe
for the purpose of emergency discharge.
The construction of the Project would commence in early 2028 with completion
of the Project by 2032, the construction period would be around 5 years. Potential source of noise impact during
construction phase of the Project would be expected from the use of power
mechanical equipment (PME) during the following construction activities of the
Project such as foundation works, superstructure works and E&M equipment
installation, etc. The site formation
for the proposed YLSEPP will be undertaken by CEDD under Agreement No. CE 35/2012
(CE) “Planning and Engineering Study for Housing Sites in Yuen Long South –
Investigation”. The major construction
works of the Project would only include superstructure works for the YLSEPP and
a short section of effluent discharge pipe connecting to the Yuen Long Nullah. Details of the proposed construction methods
and sequence of works are described in Section 2 of this EIA Report.
4.5.1.2
As
described in Section 2 of this EIA Report, the foundation options are highly
dependent on the ground conditions.
Since the proposed boundary of YLSEPP is currently located within
private land lots with numerous existing private structures, the area
assessable for ground investigation works is limited. As such, the technical
feasibility of different foundation options should be further reviewed at a
later project stage when more ground information can be gathered. Should the percussive pilling construction
method to be used for the Project, a CNP, as mentioned in Section 4.2.3.5,
will be applied during construction phase of the Project.
4.5.1.3
The
construction programme at the time of assessment does not require any
construction activities using PME undertaken during restricted hours (i.e. on
all days during 1900 and 0700 hours and at any time on Sundays and public
holidays). Therefore, only noise impact
from general construction activities during the non-restricted hours have been
assessed in this EIA Report.
4.5.1.4
Based
on the current construction programme, the Project would likely interactions
with some other projects, which may have cumulative environmental impacts. Table
4.10 summarise the concurrent projects located
within 300m from the Project boundary that would contribute to the cumulative environmental
impacts during construction phase.
Table 4.10 Potential Concurrent Projects
|
Potential Concurrent Projects
|
Tentative Construction
Commencement Year
|
Tentative Commissioning
Year
|
|
Water Reclamation
Facilities
|
Under
YLS DA Stage 2 Works.
The
construction programme is yet to be confirmed
|
|
YLS DA
Stage 2 works
|
2022
|
2033
(Full
population intake)
|
|
YLS DA
Stage 3 works
|
2031
|
2038
(Target
intake year)
|
Remarks:
-
YLS DA
Stage 1 works are located more than 1km from the YLSEPP. No construction phase cumulative impact would
be anticipated.
-
With
reference to Appendices 5.4 and 5.12 of YLS DA EIA, only land resumption and
minor construction works such as site clearance would be conducted in Year 2022
– Jun 2023 and Year 2031 – Jun 2033 for YLS DA Stage 2 works and YLS DA Stage 3
works, respectively. Site formation construction
works for YLS DA phases 3 will begin no earlier than Jul 2033. No adverse construction phase cumulative
impact would be anticipated.
4.5.1.5
According
to the approved EIA Study “Agreement No. CE 35/2012 (CE) Planning and
Engineering Study for Housing Sites in Yuen Long South – Investigation”, which
is the best available information for the YLS DA project. YLS DA Stage 2 works will tentatively be
commenced in 2022 and completed in 2033. YLS DA Stage 3 works will tentatively
be commenced in 2031, while the intake year will be targeted to be 2038. However,
according to YLS DA EIA, only land resumption and minor construction works
would be anticipated during 2031 – Jun 2033 for YLS DA Stage 3, while site
formation construction activity will begin no earlier than Jul 2033. Hence, no adverse cumulative construction
phase noise impact would be anticipated from YLS DA Stage 3 works during
construction of the YLSEPP. The potential construction noise impact
arising from the YLS DA, cumulative impact associated with the construction of
YLSEPP and Water Reclamation Facilities were identified and assessed in the EIA
Study for YLS DA. In view of the latest
RODP for YLS DA, the planned NSRs at YLS DA Stage 2 located within the defined
noise assessment area will be occupied in 2033. The construction noise impacts
from the planned rising mains and planned reclaimed water pipe within the 300m
assessment area will not be addressed under this study as no detailed
information can be provided to carry out cumulative construction noise impact.
4.5.2
Operation Phase
4.5.2.1
Potential
fixed noise sources impact during operation of the proposed YLSEPP would be
generated from the operation of the fixed plants, such as pumps, air blowers,
motors, ventilation fans and extraction fans of deodourisation units, etc. at
the proposed treatment facilities. The
details of fixed plant inventory for proposed YLSEPP are provided by project
engineer and agreed by DSD and presented in Appendix
4.6. The pumps, air blowers and motors would be
located within reinforced concrete buildings, while ventilation fans would be
provided at the ventilation vents of these buildings. No fixed noise source is associated with the
effluent discharge pipe as effluent is discharged into Yuen Long Nullah by
gravity. There is
no information regarding proposed planned water reclamation facilities nearby,
thus cumulative noise will not be assessed. The Project proponent advised
the proposed YLEPP will be operated 24 hours per day, 7 days per week
throughout the year. Thus, the daytime,
evening time and night-time operational fixed noise sources impact have been
assessed.
4.6.1
Construction Phase
4.6.1.1
The
construction noise impact assessment was undertaken based on standard acoustic
principles and followed the procedures given in the GW-TM. The sound pressure level of each construction
task has been calculated, depending on the number of plant items and the
distance from NSR. The general approach
is summarized below:
·
Locate the NSRs which would most likely be affected by 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-TMs;
·
Calculate distance attenuation due to the notional separation distance
between the noise source and the NSR;
·
Apply correction due to screening effects to NSRs from the noise source;
and
·
Predict construction noise levels at NSRs in the absence of any
mitigation measures.
4.6.1.2
The
construction programme and the plant inventory (including type and quantity of
the PME used as well as percentage on time utilization) respectively presented
in Appendices 4.3 and 4.4 are confirmed by
Project Engineer to be practical and suitable for completing the proposed works
within the proposed construction programme. Based on the construction
programme, the plant inventory and the sound power level (SWL) of equipment in
Table 3 of GW-TM, the SWL of each construction activities has been calculated,
based on the type and quantity of the PME used as well as percentage on time
utilization.
4.6.1.3
To
calculate the sound pressure level of each construction activities, distance
attenuation correction has been applied.
The distance attenuation was determined by using the following formula:
Distance Attenuation in dB(A) = 20 log D + 8
where D is distance between PME and NSR in metres
4.6.1.4
The
following assumptions have been applied as well:
(i)
A +3 dB(A) façade correction was added to the predicted noise levels to
account for the facade effect at each identified representative NSR;
(ii)
All PME items required for a particular construction activity was
assumed to be located at the notional source position of the workfront where
such activity is to be performed in accordance with the GW-TM;
(iii)
As a worst-case assumption, noise impact at the nearest sensitive
facades of the residential buildings to the source positions was assessed; and
(iv)
As a worst-case assumption, noise assessment points of all NSRs were
assumed at the same height as the Project Site, i.e. G/F of all NSRs.
4.6.1.5
In
accordance with the construction programme (Appendix
4.3) at the time of the
assessment, no construction activities with PME operation would be undertaken
in the restricted hours. The predicted
construction noise impact would be compared with the noise standards mentioned
in Section 4.2.2.1.
4.6.1.6
If
exceedance of relevant noise standards is predicted, practicable direct noise
mitigation measures including the use of quieter equipment, movable noise
barriers, noise barriers, enclosures and quieter alternative methods would be
considered. Appropriate correction
factors for barrier effect would be 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
Operation Phase
4.6.2.1
The
fixed plant noise impact assessment was undertaken based on standard acoustic
principles and followed the procedures given in the IND-TM. The following standard acoustic formula was
used for calculating the sound pressure levels at the representative NAP.
SPL =
SWL – DC + FC – BC
Where:
SPL Sound Pressure Level at NAP,
in dB(A)
SWL Sound Power Level of the
PME, in dB(A)
DC Distance Attenuation, in
dB(A) (i.e. 20logD + 8 [where D is the distance in metres])
FC Façade Correction, in
dB(A) (i.e. 3 dB(A))
BC Barrier Correction, in
dB(A)
4.6.2.3
The
fixed noise plant inventory (Appendix
4.6)
for the assessment have been confirmed by Project proponent.
4.6.2.4
It was
assumed that all the fixed plant within the same location would be operated
simultaneously at any time of the day for the worst-case scenario. With reference to EPD’s Good Practices on
Pumping System Noise Control, a noise reduction of more than 20 dB(A) could be
provided by complete enclosures constructed by compressed strawboard (56mm
thick) or plastered brick wall (125mm thick). As a conservative assumption in the
assessment, noise reduction of 20 dB(A) was applied for fixed plants fully
enclosed by plastered brick wall (125mm thick and surface density of 240 kg/m2). A 10 dB(A) noise reduction acoustic louvre
would be provided for ventilation fans. A
positive 3 dB(A) was added to the predicted noise levels at the NAP due to the
façade effect.
4.6.2.5
With
reference to EPD’s Good Practices on Pumping System Noise Control and Good
Practices on Ventilation System Noise Control, a positive 3 dB(A) for
correction of tonality has been considered in the assessment.
4.6.2.6
The
predicted noise levels at the representative NAPs were compared with criteria
set out in Table
4.9 above. Mitigation measures have been
recommended in cases where an exceedance is predicted.
4.7.1
Construction Phase
4.7.1.1
Potential
noise impacts from construction of the proposed YLSEPP during non-restricted hours
have been assessed at the representative NAPs based on the construction
programme as shown in Appendix 4.3 and the construction plant inventory
presented in Appendix 4.4. The
unmitigated noise assessment results are summarised in Table 4.7. Details of the construction unmitigated noise
assessment are presented in Appendix 4.5.
Table 4.11 Predicted Construction Noise Levels at
Representative Noise Assessment Points under Unmitigated Scenario
|
NAP ID
|
Noise
Criteria,
Leq 30-min, dB(A)
|
Predicted Construction
Noise Level due to Construction of YLSEPP, Leq 30-min, dB(A)
|
Predicted Cumulative
Construction Noise Level,
Leq 30-min, dB(A)
|
|
YE01
|
75
|
78 - 81
|
79 - 82
|
|
YE02
|
75
|
72 - 77
|
76 - 79
|
|
YE03
|
75
|
61 - 73
|
67 - 74
|
|
YE04
|
75
|
61 - 73
|
65 - 73
|
Note:
·
Boldfaced values indicate exceedance of noise
criteria.
4.7.1.2
Referring
to Table
4.11, in the absence of noise mitigation
measures, non-compliance of the construction noise criterion would be predicted
at the representative NAPs YE01 and YE02.
Hence, direct mitigation measures would be required to alleviate the
potential construction noise impact on the affected NSRs during construction.
4.7.2.1
Referring
to the latest design, the sound power levels of the fixed plants under the
worst-case scenario in the fixed noise sources impact assessment are presented
in Appendix 4.6. Details of the fixed noise calculation are
also presented in Appendix 4.6. A
summary of the fixed noise sources impact assessment results at the
representative NAPs during the operation phase of the Project is shown in Table
4.12. The
predicted fixed noise levels at the NAPs would comply with the respective noise
criteria. No adverse fixed noise impact
would be anticipated. Therefore, there is no dwelling, classroom or other NSR
that will be exposed to fixed noise impact exceeding criteria set out in Annex
5 of EIAO-TM.
Table
4.12 Predicted Fixed Noise Levels under Unmitigated Scenario
|
NAP ID
|
Noise
Criteria,
Leq 30-min, dB(A)
|
Predicted Fixed Noise
Level,
Leq 30-min, dB(A)
|
|
Day
(1)
|
Evening
(2)
|
Night
(3)
|
|
YE03
|
49
|
49
|
45
|
43
|
|
YE04
|
49
|
49
|
45
|
43
|
|
YP01
|
49
|
49
|
47
|
41
|
|
YP02
|
49
|
49
|
47
|
42
|
|
YP03
|
49
|
49
|
47
|
42
|
|
YP04
|
49
|
49
|
47
|
42
|
|
YP05
|
49
|
49
|
47
|
44
|
Notes:
(1)
Daytime means 07:00 – 19:00.
(2)
Evening time means 19:00 – 23:00.
(3)
Night-time means 23:00 – 07:00 of the next day.
(4)
Boldfaced indicates exceedance to night-time criterion.
4.8.1
Construction Phase
4.8.1.1
Due to
the predicted exceedance of the construction noise criteria under unmitigated
scenario, noise mitigation measures are recommended as follow. Construction noise mitigation measures are
recommended as in Table
4.13.
These recommended construction noise mitigation measures should be
included in the Contract
Specification for the Contractors to follow and implement the relevant
measures to further minimize the potential noise impacts during the
construction phase of the Project.
Table 4.13 Recommended Construction Noise Mitigation
Measures
|
Recommended
Mitigation Measures
|
Construction
Plant
|
Noise
Reduction,
Leq
30 min dB(A)
|
|
Temporary
movable noise barrier
|
Excavator,
Mobile crane, Dump truck, Grout mixer and Grout pump
|
5
|
|
Noise
insulating fabric
|
Drilling
rig and Piling machine
|
10
|
|
Ventilated
acoustic enclosure
|
Generator
|
15
|
|
Quiet PME
|
Excavator
(1) and Mobile crane (2)
|
Refer to Appendix 4.7
|
Notes:
(1)
KOBELCO SK125SR (EPD-11011) referenced from the QPME system published by
EPD is recommended as a quiet PME for excavator.
(2)
Kobelco CKS900 (EPD- 09602) referenced from the QPME system published by
EPD is recommended as a quiet PME for mobile crane.
4.8.1.2
Temporary
movable noise barriers should be made of materials with density of at least 10
kg/m2 to provide sufficient noise reduction. No sound leaks should be allowed through the
barriers due to holes, slits, cracks, openings or gaps. Noise barriers will become more effective
when located immediately adjacent to the work area and can reduce the noise
level by up to 5dB(A) and 10dB(A) for mobile and stationary plant respectively.
With reference to GW-TM, noise attenuation of 5 dB(A) is applied when this type
of PME would be screened from NSR’s view.
4.8.1.3
Noise
insulating fabric of at least 10 dB(A) reduction should be used to alleviate
noise emission from the respective plant.
The fabric should be lapped such that there would be no opening or gaps
on the joints. Hence, the noise reduction effect from the fabric could be
maximised.
4.8.1.4
Enclosing
generator by a ventilated acoustic enclosure can provide a noise reduction of
up to 20 dB(A) with reference to Table B.1 of BS 5228-1:2009+A1:2014 Code of
Practice for Noise and Vibration Control on Construction and Open Sites – Part
1: Noise. As a conservative assumption,
15 dB(A) reduction is assumed for this assessment.
4.8.1.5
Quiet
PME labelled under EPD’s Quality Powered Mechanical Equipment (QPME) System
should be considered as far as practicable to reduce the potential noise
emission from PME. In particular, quiet PME
for excavator and mobile crane should be used as referenced in Appendix
4.7 to ensure the noise performance of the PME.
4.8.1.6
The
construction plant inventory for the assessment of mitigated scenario is
presented in Appendix 4.7. The
details of construction noise impact assessment under mitigated scenario are
presented in Appendix 4.8 and the mitigated noise levels at NAPs are
summarized in below Table
4.13.
With the implementation of the above proposed mitigation measure, the
predicted mitigated construction noise levels at the NAPs would comply with
relevant noise criteria. No adverse
construction noise impact would be anticipated.
No further noise mitigation measures would be required.
Table 4.14 Predicted Construction Noise Levels at
Representative Noise Sensitive Receivers under Mitigated Scenario
|
NAP ID
|
Noise
Criteria,
Leq 30-min, dB(A)
|
Predicted Construction
Noise Level due to Construction of YLSEPP, Leq 30-min, dB(A)
|
Predicted Cumulative
Construction Noise Level,
Leq 30-min, dB(A)
|
|
YE01
|
75
|
64 - 71
|
74 - 75
|
|
YE02
|
75
|
58 - 67
|
74 - 75
|
|
YE03
|
75
|
53 - 68
|
66 - 70
|
|
YE04
|
75
|
53 - 68
|
63 - 69
|
4.8.1.7
In addition to the above construction noise
mitigation measures, good site practices listed below and the noise control
requirements stated in EPD’s “Recommended Pollution Control Clauses for
Construction Contracts” should be included in the Contract Specification for the Contractors to
follow and implement the relevant measures to further minimize the
potential noise impacts during the construction phase of the Project.
·
Quiet PME,
such that those listed in EPD’s Quality Powered Mechanical Equipment, should be
considered for construction works to further minimize the potential
construction noise impact.
·
Only
well-maintained plant should be operated on-site and plant should be serviced
regularly during the construction programme.
·
Silencers
or mufflers on construction equipment should be utilised and should be properly
maintained during the construction programme.
·
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 so that the noise is directed away from the nearby NSRs
·
Material
stockpiles and other structures should be effectively utilised, wherever
practicable, in screening noise from on-site construction activities.
4.8.1.8
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 and submitted to EPD 3 months prior to the commencement of the
construction works.
4.8.2
Operation Phase
4.8.2.1
No
adverse fixed noise sources impact would be anticipated during operation of the
Project.
4.9.1
Construction Noise
4.9.1.1
No
residual noise impact due to the construction of the Project is anticipated.
4.9.2
Operational Fixed Plant Noise
4.9.2.1
No
residual fixed plant noise impact due to the operation of the Project is
anticipated.
4.10.1
Construction Noise
4.10.1.1
With
the implementation of the above proposed mitigation measures, residual
construction noise impact would not be anticipated. An Environmental Monitoring and Audit
(EM&A) programme is recommended to ensure the proper implementation of the
proposed mitigation measures and good site practices, and take remedial
measures when non-compliance is recorded.
4.10.2
Operational Fixed Noise
4.10.2.1
No
adverse fixed noise sources impact is anticipated during the operation of the
YLSEPP. Commissioning test should be
conducted prior to operation of the Project to ensure fixed noise sources
impact would comply with the relevant noise standards. No operation noise monitoring is therefore deemed
necessary.
4.11.1
Construction Phase
4.11.1.1
The
assessment for the potential construction noise impact from construction of the
proposed YLSEPP and its cumulative impact with concurrent projects have been
conducted. The assessment results
indicate that the predicted construction noise levels of the Project at the
NAPs would exceed the noise criteria without mitigation measures. With mitigation measures in place, the
predicted construction noise levels at all NAPs due to Project would comply
with the noise criteria. Thus, no
adverse construction noise impact arising from the Project would be anticipated. Based on best available information the
cumulative construction noise levels at the NAPs would also comply with the
noise criteria. No adverse cumulative
construction noise impact would be anticipated due to the Project and
concurrent projects.
4.11.2
Operation Phase
4.11.2.1
The fixed
noise sources impact associated with the operation of the YLSEPP has been
assessed based on the plant design information provided by the Project Engineer
at the time of the assessment. The
assessment results indicate that the predicted fixed noise levels at the NAPs
would comply with the noise criteria under unmitigated scenario. No adverse fixed noise sources impact due to
the operation of the YLSEPP would be anticipated. Commissioning test should be conducted prior
to operation of the Project to ensure that the fixed noise sources impact would
comply with the relevant noise standards.