8
Airborne Noise Impact Assessment
This chapter presents the findings
of the airborne noise assessment of the Project during both construction and
operational phases.
Construction noise impacts associated
with the use of Powered Mechanical Equipment (PME) and operational noise
impacts associated with fixed noise sources and railways have been evaluated.
Practical mitigation measures would be recommended appropriately to control
construction and operational noise impacts at all noise sensitive uses to
acceptable levels.
8.2.1 Construction Noise
The Noise Control Ordinance (NCO)
(Cap. 400)[8-1] provides the statutory framework for noise control
in
·
TM
on Noise from Construction Work other than Percussive Piling (TM-GW)[8-2];
·
TM
on Noise from Percussive Piling (TM-PP)[8-3]; and
·
TM
on Noise on Construction Work in Designated Areas (TM-DA)[8-4].
For construction activities, there
is no statutory limit on daytime construction noise under the NCO and related
TMs. To ensure a better environment, the
Annex 5 of TM-EIAO[8-5] promulgated under the Environmental Impact
Assessment Ordinance (EIAO) (Cap. 499) has imposed more stringent criteria for
daytime construction activities of designated projects. A summary of noise standards for construction
activities of designated projects are shown in Table
8.1.
Table 8.1: Noise
Standards for Construction Activities
|
Uses |
Noise Standards [1] , Leq (30 mins)
dB(A) |
|
|
0700
to 1900 hours on
any day not being a Sunday or general
holiday |
1900
to 0700 hours or
any time on Sundays or
general holiday |
|
|
All
domestic premises including temporary housing accommodation |
75 |
(See Note 2) |
|
Hotels
and hostels |
75 |
|
|
Educational
institutions including kindergartens, nurseries and all others where unaided
voice communication is required |
70 65 (During examinations) |
|
Notes:
[1] The above standards apply to uses that rely on opened windows
for ventilation.
[2] The criteria laid down in the relevant technical memoranda
under the NCO for designated areas and construction works other than percussive
piling may be used for planning purpose. A Construction Noise Permit (CNP)
shall be required for the carrying out of construction work during the period.
8.2.1.1
Construction
Noise during Restricted Hours
The NCO also provides statutory
control on general construction works during restricted hours (i.e. 1900 to
0700 hours (of the next day) from Monday to Saturday and at any time on Sundays
or public holidays). The use of Powered Mechanical Equipment (PME) for
construction works during restricted hours would require a Construction Noise
Permit (CNP). The TM-GW details the
procedures adopted by EPD for assessing such application. The granting of a CNP is subject to conditions
stated in the CNP and it may be revoked at any time for failure to comply with
the permit conditions.
In addition to the general controls
on the use of PME during restricted hours, the use of Specified Powered
Mechanical Equipment (SPME) and the undertaking of Prescribed Construction Work
(PCW) during the restricted hours in a designated area are controlled by the
TM-DA. Construction plant or equipment classified as SPME under the TM-DA
includes hand-held breakers, bulldozers, concrete mixer lorries, dump trucks
and poker vibrators. The PCW includes
the erection or dismantling of formwork or scaffolding, hammering, handling of
rubble, wooden boards, steel bars, or scaffolding material, and the disposal of
rubble through plastic chutes.
The TM-DA details the procedures
that should generally be adopted by the Authority for assessing the use of SPME
during restricted hours and for determining whether a CNP would be issued.
Maximum noise levels from
construction activities during restricted hours at affected NSRs are controlled
under the TMs and shall not exceed the specified Acceptable Noise Levels
(ANLs). These ANLs are stipulated in accordance with the Area Sensitivity
Ratings established for the NSRs. The ANLs for construction works in Designated
Areas are more stringent than those given in the GW-TM and summarised in Table 8.2.
Table 8.2: Acceptable Noise Levels for Construction during Restricted
Hours
Time Period |
Acceptable Noise Levels for Area Sensitivity
Ratings, dB(A) |
||
|
A |
B |
C |
|
|
All weekdays during the evening (1900 to 2300 hours), and general holidays (including Sundays) during the day and evening (0700 to 2300 hours) |
60 (45) |
65 (50) |
70 (55) |
|
All days during the night-time (2300 to 0700 hours) |
45 (30) |
50 (35) |
55 (40) |
Note: Figures in brackets
are ANLs for SPME construction work in designated areas
Despite any description made in this
EIA, 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. The Noise Control Authority will take into account contemporary
conditions / situations of adjoining land uses and any previous complaints
against construction activities at the site before making a decision in
granting a CNP. Nothing in the EIA
Report shall bind the Noise Control Authority in making a decision. If a CNP is
to be issued, the Noise Control Authority shall include in it any conditions
demand. Failure to comply with any such
conditions will lead to cancellation of the CNP and prosecution under the NCO.
8.2.1.2
Percussive
Piling
Under the TM-PP, CNPs are also
required for percussive piling involving the use of diesel, pneumatic and / or
steam hammer. This TM specifies the permitted hours and other conditions for
percussive piling. Table
8.3 lists the acceptable percussive piling noise levels for
various types of NSR.
Table
8.3: Acceptable Noise Levels for Percussive Piling
|
NSR Window Type or Means of
Ventilation |
ANL
(dB(A)) |
|
(i) NSR (or part of NSR) with no window or
other opening |
100 |
|
(ii) NSR with central air conditioning system. |
90 |
|
(iii) NSR with windows or other openings but
without central air conditioning system |
85 |
Depending on the numbers and types of
piling machines and the separation from NSRs, percussive piling may be
restricted to 12, 5 or 3 hours per day.
For NSRs that are particularly sensitive to noise, such as hospitals,
medical clinics, educational institutions and courts of law, a further reduction
of 10 dB(A) shall be applied to the above ANLs.
8.2.2 Operational Noise
The TM-EIAO has stipulated the noise
standards for various noise sources as shown in the following table.
Table 8.4 Noise Standards for Operational Phase
Notes:
[1] The above standards apply to
uses that rely on opened windows for ventilation.
[2] Rail noise is under the
control of the Noise Control Ordinance and shall comply with the Acceptable Noise
Levels laid down in the Technical Memorandum for the Assessment of Noise from
Places other than Domestic Premises, Public Places or Construction Sites. The criteria for noise transmitted primarily
through the structural elements of the building or buildings should be 10dB(A)
less than the relevant acceptable noise level.
8.2.2.1
Railway
Noise
Noise from railway, station
plant items, train stabling sidings and ventilation building is controlled
under the NCO and the associated Technical Memorandum on Noise from Places
Other Than Domestic Premises, Public Places or Construction Sites (TM-Places),
and the relevant noise criteria are listed in Table 1A, Annex 5 of
TM-EIAO. In accordance with
the Hong Kong Planning Standards and Guidelines (HKPSG), a 24-hour averaged
noise level of 65 dB(A) Leq 24 hr has been specified.
Table 8.5 below summarises the noise standards for
railway noise as given in Table 1A, Annex 5 of TM-EIAO.
Table 8.5: Noise Criteria for Railway Noise
|
Area Sensitivity Rating |
Time Period [1] |
Acceptable Noise Levels (ANL), LAeq, 30 mins,
dB(A) |
Maximum A-weighted
sound pressure level, Lmax (2300-0700hrs) dB(A) |
|
A |
Day & evening |
60 |
85 |
|
Night |
50 |
||
|
B |
Day & evening |
65 |
|
|
Night |
55 |
||
|
C |
Day & evening |
70 |
|
|
Night |
60 |
Note:
[1] Day: 0700 to 1900 hours,
Evening: 1900 to 2300 hours, Night: 2300 to 0700 hours
8.2.2.2
Fixed
Noise Sources
Operational noise from
fixed noise sources including station plant building and ventilation shafts is controlled
under the NCO’s Technical Memorandum on Noise from Places other than Domestic
Premises, Public Places or Construction Sites[8-6]. To plan for a
better environment, the TM-EIAO has specified the following requirements.
·
5
dB(A) below the appropriate ANLs in the Technical Memorandum on Noise from
Places other than Domestic Premises, Public Places or Construction Sites; or
·
the
existing noise levels (For quiet areas with
level 5dB(A) below the ANL).
The ANLs for different Area
Sensitivity Ratings during different periods are summarized in the following
table.
Table 8.6: Acceptable Noise Levels (ANL) for
Fixed Noise Sources stated in TM-Places
|
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 |
Note: ASR
– Area Sensitivity Rating
* 5 dB(A) below the appropriate ANLs in the
TM-Places will be taken as the assessment criterion
8.2.2.3
Existing
Noise Levels
Noise measurements have
been conducted to establish the existing noise levels in the vicinity of the
proposed ventilation shafts and stations where fixed noise sources are
anticipated. Appendix 8.1 shows the
measurement locations for existing noise levels. A summary of the results is given in Table 8.7.
Table 8.7: Measurements of
Existing Noise Levels
Note:
[1] Day: 0700 to 1900 hours,
Evening: 1900 to 2300 hours, Night: 2300 to 0700 hours
[2] Measurements conducted in
March 2009 and July 2011
8.2.2.4
Noise
Criteria
A summary of the noise criteria at representative NSRs which would be
subject to the impact of fixed plant noise is given in the following
table. The existing noise level at each
NSR would be determined based on measurement results at the nearest location as
shown in Appendix 8.1.
Table 8.8: Summary of Noise Criteria at NSRs
for Fixed Noise Sources
|
Area (NSR No.) |
Time Period [1] |
Existing Noise Levels, dB(A) [2] |
ASR |
ANL-5 dB(A) [3] |
Criteria dB(A) [4] |
|
|
Day & evening |
68 |
C |
65 |
65 |
|
Night |
62 |
C |
55 |
55 |
|
|
University Student Halls of Residence
(HUH-11-1), Harbour Place Block 6
(HUH-12-1) |
Day & evening |
65 |
C |
65 |
65 |
|
Night |
61 |
C |
55 |
55 |
|
|
The |
Day & evening |
72 |
B |
60 |
60 |
|
Night |
65 |
B |
50 |
50 |
|
|
Harbourfront Horizon HUH-10-1 |
Day & evening |
64 |
B |
60 |
60 |
|
Night |
64 |
B |
50 |
50 |
|
|
Planned NSR (KAT-P1-1, KAT-P1-2, KAT-P1-3 & KAT-P1-4) |
Day & evening |
70 |
B |
60 |
60 |
|
Night |
56 |
B |
50 |
50 |
|
|
Galaxia (DIH-12-1 & DIH-12-2), Lung Wan House (DIH-11-1), |
Day & evening |
69 |
C |
65 |
65 |
|
Night |
62 |
C |
55 |
55 |
|
|
Shek On Building(DIH-9-1), Hong Kong Sheng Kung Hui Nursing Home (DIH-10-1) |
Day & evening |
76 |
B |
60 |
60 |
|
Night |
71 |
B |
50 |
50 |
|
|
|
Day & evening |
72 |
C |
65 |
65 |
|
Night |
63 |
C |
55 |
55 |
Note:
[1] Day: 0700 to 1900 hours, Evening:
1900 to 2300 hours, Night: 2300 to 0700 hours.
[2] Existing noise level determined
based on the measurement result recorded at the representative location nearest
to the respective NSR.
[3] A 5 dB(A) has been deducted from
ANL as specified in requirement of TM-EIAO.
[4] The Minimum of [2] & [3] is
adopted.
The concurrent projects that would
have cumulative environmental impacts during the construction and operational
phases of SCL (HHS) are given in Section
1. As discussed in Section 1.5.12,
the following concurrent projects are relevant for cumulative noise
assessment.
Table 8.9 Summary of Cumulative Noise Issues
from Concurrent Projects
|
Item |
Project |
Issues During Project Stage |
|
|
Construction |
Operation |
||
|
1.
|
SCL – Tai Wai to Hung Hom Section (SCL (TAW-HUH)) |
• Construction noise |
• Railway noise |
|
2.
|
SCL – Mong Kok East to Hung Hom Section (SCL (MKK-HUH)) & SCL –
Hung Hom to Admiralty Section (SCL (HUH-ADM)) |
• Construction noise |
• Railway noise and fixed noise |
|
3.
|
Housing Authority Development Sites 1A & 1B within Kai Tak
Development |
• Nil |
|
|
4.
|
Other Infrastructure within Kai Tak Development |
• Nil |
|
|
5.
|
Kwun Tong Line Extension (Including EPIW) (KTE
with EPIW) |
• Construction noise |
• Nil |
|
6.
|
Tsz Wan Shan Pedestrian Link |
• Construction noise |
• Nil |
|
7.
|
Central |
• Construction noise |
• Nil |
According to the project proponent
of SCL (TAW-HUH), the SCL (TAW-HUH) project is scheduled to commence
concurrently with the Project. All the construction works, including site
clearance, ground excavation, cu-&-cover tunnel section, etc. presented in
the EIA report for SCL (TAW-HUH) would be included in this assessment to
account for the cumulative impacts.
However, noise sources from construction of Diamond Hill Stabling Siding
(DHS), KAT and DIH based on the scheme assessed in the SCL (TAW-HUH) would not
be included in the cumulative assessment as it is assumed in this EIA that the
HHS options would be adopted and emissions from the construction of these
elements would be assessed based on the scheme proposed under the Project.
Hung Hom Area
SCL – Tai Wai to
Hung Hom Section
As mentioned above, the construction
activities in the vicinity of HHS and HUH presented in the SCL (TAW-HUH) EIA
Report would be included in the cumulative impact assessment.
SCL – Mong Kok
East to Hung Hom Section and Hung Hom to Admiralty Section
The SCL (MKK-HUH) and SCL (HUH-ADM)
projects in the Hung Hom Area are scheduled to commence concurrently with the
Project. Cumulative construction noise
impact is therefore anticipated. SCL (MKK-HUH) will include the realignment
work for the existing East Rail Line tracks from south of Mong Kok East to the
modified HUH. SCL (HUH-ADM) will include the construction of the section across
the harbour from Hung Hom to Admiralty.
As this EIA addresses the HHS option, noise sources from the
construction of HUH based on the scheme assessed in the SCL (MKK-HUH) would not
be included in the cumulative assessment.
Noise impact induced from the construction of HUH would be assessed as
per the scheme proposed under this Project.
Central
According
to the project proponent of CKR, the CKR project is scheduled to commence
concurrently with the Project. As the construction impacts from CKR at the
identified NSRs would be screened by nearby buildings, cumulative impact from
construction of CKR and the Project is therefore not anticipated.
Kwun Tong Line
Extension with EPIW
With
reference to the approved EIA Study “Kwun Tong Line Extension”
(AEIAR-154/2010), construction works under KTE project would occur concurrently
with the Project. KTE project will include construction of an approximately 3km
extension of the existing Kwun Tong Line from Yau Ma Tei Station to a new
railway station at Whampoa and an interchange with SCL (TAW-HUH) at Ho Man Tin
Station. Three EPIW items, namely Oi Man Estate and Ho Man Tin Estate
Connections, Public Transport Facilities and Chatham Road North Covered
Footbridge, would also occur concurrently. Cumulative construction noise impact
from construction of KTE with EPIW and HHS and modification of HUH is
anticipated.
Kai Tak Area
SCL – Tai Wai to
Hung Hom Section
The construction works proposed for
SCL(TAW-HUH) in the Kai Tak area would be located at within 300m from the
nearest representative NSRs identified for this Project. As mentioned above, all the construction
works in the vicinity of DIH presented in the EIA report for SCL (TAW-HUH)
would be included in this assessment to account for the cumulative
impacts. However, noise sources from
construction of Diamond Hill Stabling Siding (DHS), KAT and DIH based on the
scheme assessed in the SCL (TAW-HUH) would not be included in the cumulative
assessment as it is assumed in this EIA that the HHS options would be adopted
and emissions from the construction of these elements would be assessed based
on the scheme proposed under the Project.
Diamond Hill Area
SCL – Tai Wai to
Hung Hom Section
As mentioned above, all the
construction works in the vicinity of DIH presented in the EIA report for SCL
(TAW-HUH) would be included in this assessment to account for the cumulative
impacts. However, noise sources from
construction of Diamond Hill Stabling Siding (DHS), KAT and DIH based on the
scheme assessed in the SCL (TAW-HUH) would not be included in the cumulative
assessment as it is assumed in this EIA that the HHS options would be adopted
and emissions from the construction of these elements would be assessed based
on the scheme proposed under the Project.
Tsz Wan Shan
Pedestrian Link
Tsz Wan Shan Pedestrian Link is a
covered walkway as well as lifts/escalators proposed to connect the Tsz Wan
Shan residential to the DIH Station. Based on the current construction
programme, the associated construction works would likely interface with the
major construction of the Project, cumulative construction noise impact is
anticipated.
8.4.1
Noise
Sensitive Receivers
With reference to Annex 13 of the
TM-EIAO, NSRs include residential uses (all domestic premises including
temporary housing), institutional uses (educational institutions including kindergarten
and nurseries), hospitals, medical clinics, homes for the aged, convalescent
homes, places of worship, libraries, court of law, performing arts centres,
auditoria and amphitheatres, country park and others. All hospitals and
performance venues are air-conditioned and do not rely on openable windows for
ventilation.
Representative NSRs within a
distance of 300m from either side of the project boundary have been identified.
The first layer of NSRs has been identified and selected for assessment. These
NSRs will cover all existing sensitive developments (including those occupied
before completion of the construction) for construction noise assessment, and
both the existing and planned developments for operational noise assessment.
The existing NSRs are identified by
means of topographic maps, aerial photos, land status plans and several site
surveys. Planned/committed NSRs are identified by making reference to relevant
Outline Zoning Plans, Outline Development Plans, Layout Plans and other published
plans in relation to the Planning and Development.
The existing and planned NSRs in the
vicinity, which may be affected by the proposed SCL (HHS) are summarised in the
following Table 8.10 and Table 8.11. The
locations of the NSRs are shown on Figures 8.1.1 to
8.1.3. Details and photos of NSRs are given in Appendices 8.2 and 8.3 respectively.
Table
8.10: Existing NSRs
|
NSR ID |
NSR
Description |
Landuse [1] |
No. of
Storey |
|
DIH-9-1 |
Shek On
Building |
E
+ W |
5 |
|
DIH-10-1 |
Hong Kong
Sheung Keung Hui Nursing Home |
H |
9 |
|
DIH-11-1 |
Lung |
R |
34 |
|
DIH-12-1 |
Galaxia
Tower B |
R |
44 |
|
DIH-12-2 |
Galaxia
Tower E |
R |
43 |
|
DIH-13-1 |
|
E |
5 |
|
DIH-14-1 |
|
R |
22 |
|
DIH-14-3 |
|
R |
22 |
|
DIH-14-4 |
|
E |
6 |
|
DIH-14-5 |
|
R |
22 |
|
DIH-15-1 |
Choi Hung Estate - Kam Wan House |
R |
20 |
|
DIH-15-2-A |
Choi Hung
Estate - Pik Hoi House |
R |
20 |
|
HUH-1-3 |
|
R |
8 |
|
HUH-3-1 |
|
R |
42 |
|
HUH-3-2 |
|
R |
35 |
|
HUH-4-1 |
The
Metropolis Residence Tower 2[2] |
S |
18 |
|
HUH-4-2 |
The
Metropolis Residence Tower 1[2] |
S |
18 |
|
HUH-8-1 |
No. 2, |
R |
6 |
|
HUH-10-1 |
Harbourfront
Horizon[3] |
C
+ S |
22 |
|
HUH-11-1 |
The Hong Kong Polytechinic University Jockey Club Student Hostel |
R |
20 |
|
HUH-12-1 |
Harbour Place Block 6 |
R |
35 |
Notes:
[1] R– residential premises; E – educational institutions; W –
worship; H – clinic / home for the aged; S – Service Apartment; C – Commercial
[2] Metropolis
Residence is a service apartment and shall not rely on openable windows for ventilation.
Nonetheless, for conservative consideration that occupier might open window
under special circumstances, this premise has been considered as an assessment
point.
[3] Harbourfront
Horizon shall not rely on openable windows for ventilation. Nonetheless, for
conservative consideration that occupier might open window under special
circumstances, this premise has been considered as an assessment point.
Table
8.11: Planned NSRs
|
NSR
ID |
NSR
Description |
Landuse
[1] |
No.
of Storey |
|
DIH-P3-1 to
P3-2 |
Future
receivers in the CDA Site |
R/GIC |
[2] |
|
KAT-P1-1 to
6 |
Residential
premises near KAT |
R |
14 -
57 |
Notes:
[1] R– residential premises; GIC – government, institution and
community
[2] To be determined by respective project proponents
8.5.1
General
Assessment Procedure
Construction noise
assessment has been conducted based on the following procedures:
·
Determine
the assessment area, and identify representative NSRs that may be affected by
the works;
·
Obtain
the construction method and work sequence for the construction period;
·
Obtain
the plant items for each corresponding construction work sequence;
·
Determine
the sound power levels of the plant items according to the information stated
in the TM-GW or other recognised sources of reference, where appropriate;
·
Calculate
the correction factors based on the distance between the NSRs and the notional
noise source positions of the work sites;
·
Apply
corrections for façade, distance, barrier attenuation, acoustic reflection
where applicable;
·
Quantify
the level of impact at the NSRs, in accordance with TM-GW;
·
Predict
the cumulative noise impacts by any concurrent construction works in the
vicinity; and
·
For
any exceedance of noise criteria, all practical mitigation measures such as
alternative construction methodology, quiet plant, silencer, enclosure, etc,
shall be examined to alleviate the predicted noise impacts as much as
practicable. Details of mitigation measures are discussed in Section 8.5.6.
8.5.2
Construction
Noise Sources
Based on the
construction methodologies, the major construction works would include the
following activities for construction of HHS, KAT and DIH and modification
works at HUH:
·
Site
clearance and formation activities;
·
Structure
dismantling, if required;
·
Station,
ventilation shafts and train stabling sidings construction;
·
Tunnel
and refuge sidings construction (including bored tunnelling, cut-&-cover and
open cut)
·
Diversion
of utilities; and
·
Backfilling
and reinstatement works.
These construction
activities would be carried out with the use of Powered Mechanical Equipment
(PME) including breakers, pipe pile rigs, excavators, lorries, mobile cranes,
concrete pumps, concrete mixers, pokers, rollers, etc. Sound Power Levels
(SWLs) for each PME would be established according to TM-GW and other relevant
information as appropriate.
The plant inventory
for the above activities is provided by the Project Proponent and is given in Appendix 8.4.
8.5.3
Utilisation
Rates of Powered Mechanical Equipment
Practically, the PMEs will not be
operating for all times within a work site. The utilization rates would depend
on the construction sequences, work fronts scale and construction nature. In
this assessment, the utilization rates for each work front during different
periods have been reviewed by the Project Proponent and have been concluded to
be practicable for the purpose of this EIA. Appendix 8.4
summarises the adopted
utilisation rates and the associated SWL for different construction sequences. Appendix 8.5
shows the sketch of typical temporary noise barrier / enclosure.
8.5.4
Noise
Assessment Tool
An in-house program has been used
for construction noise calculations. Initially, the program runs were conducted
without any mitigation measures (i.e. the “Unmitigated Scenario”). Where noise
level exceedance was identified, further runs would be made assuming different
combinations of mitigation measures to be incorporated (i.e. the “Mitigated
Scenario”).
8.5.5 Assessment Results - Unmitigated
Scenario
According to the latest engineering
design, the construction would mainly comprise of the activities as described
in Section 8.5.2. The corresponding Sound Power Levels (SWLs)
of these activities have been estimated according to the PME’s SWLs and the
assessment methodology in the GW-TM. Appendix 8.7A to Appendix 8.10A present
the PME inventory adopted in each construction works area, including HUH and
HHS, KAT and DIH. Appendix 8.7B to Appendix 8.10B
present the distance between the notional sources and the NSRs and screening
effects due to terrains etc. Appendix 8.7C to Appendix 8.10C present
the monthly unmitigated noise contribution during the construction period. Appendix 8.7D to Appendix 8.10D
also present the unmitigated construction noise impacts at selected
representative NSRs. The predicted construction noise impacts on the NSRs are
summarised in the tables below.
Table 8.12: Predicted Maximum Unmitigated Construction
Noise Levels at Noise Sensitive Receivers
|
NSR
ID |
NSR
Description |
Uses |
Criterion [1] dB(A) |
Unmitigated Noise Level [2] dB(A) |
Exceedance dB(A) |
|
Works Area – HUH and HHS |
|||||
|
HUH-1-3 |
|
R |
75 |
78 |
3 |
|
HUH-3-1 |
|
R |
75 |
81 |
6 |
|
HUH-3-2 |
|
R |
75 |
81 |
6 |
|
HUH-4-1 |
The
|
S |
75 |
81 |
6 |
|
HUH-4-2 |
The
|
S |
75 |
80 |
5 |
|
HUH-8-1 |
No.
2, |
R |
75 |
75 |
0 |
|
HUH-10-1 |
Harbourfront
Horizon |
C + S |
75 |
84 |
9 |
|
Works Area – KAT |
|||||
|
KAT-P1-5-A |
Residential
premises near KAT |
R |
75 |
75 |
0 |
|
KAT-P1-5-B |
Residential
premises near KAT |
R |
75 |
90 |
15 |
|
KAT-P1-5-C |
Residential
premises near KAT |
R |
75 |
76 |
1 |
|
KAT-P1-5-D |
Residential
premises near KAT |
R |
75 |
81 |
6 |
|
KAT-P1-6 |
Residential
premises near KAT |
R |
75 |
78 |
3 |
|
Works Area – DIH |
|||||
|
DIH-9-1 |
Shek
On Building |
E + W |
70 (65) |
77 |
7 (12) |
|
DIH-10-1 |
Hong
Kong Sheung Keung Hui Nursing Home |
H |
75 |
77 |
2 |
|
DIH-11-1 |
Lung
|
R |
75 |
88 |
13 |
|
DIH-12-1 |
Galaxia
Tower B |
R |
75 |
81 |
6 |
|
DIH-12-2 |
Galaxia
Tower E |
R |
75 |
82 |
7 |
|
DIH-13-1 |
|
E |
70 (65) |
75 |
5 (10) |
|
DIH-14-1 |
|
R |
75 |
75 |
0 |
|
DIH-14-3 |
|
R |
75 |
62 |
0 |
|
DIH-14-4 |
|
E |
70 (65) |
78 |
8 (13) |
|
DIH-14-5 |
|
R |
75 |
77 |
2 |
|
DIH-15-1 |
Choi Hung Estate - Kam Wan
House |
R |
75 |
67 |
0 |
|
DIH-15-2A |
Choi
Hung Estate - Pik Hoi House |
R |
75 |
62 |
0 |
Notes:
[1] Values in parentheses indicate the noise
criterion during examination period of educational institution.
[2] Bolded
values mean exceedance of the noise criteria.
Results show
that, without any mitigation measures, the predicted construction noise levels
during non-restricted hours would exceed the corresponding noise criteria at
most of the selected NSRs by 2 to 15dB(A) and 5 to 13dB(A) for
residential premises and educational institution respectively, especially for
those NSR very close to cut-&-cover station construction. Mitigation measures
are therefore considered necessary to reduce the adverse construction noise
impact associated with the Project at all works area.
8.5.6
Mitigation
Measures
The predicted
construction noise levels show that the unmitigated construction noise impacts
would exceed the daytime noise criteria.
Mitigation measures are therefore required. The following mitigation
measures have been considered:
·
Good
site practices to limit noise emissions at the source;
·
Use
of quiet plant and working methods;
·
Use
of site hoarding as noise barrier to screen noise at ground level of NSRs;
·
Use
of shrouds / temporary noise barriers to screen noise from relatively static
PMEs;
·
Use
of large full enclosure to screen all the plant;
·
Scheduling
of construction works outside school examination periods in critical area; and
·
Alternative
use of plant items within one worksite, wherever practicable.
The above
mitigation measures would need to be implemented in all work sites as good
practices. It should be noted that
whilst “Good Practice” mitigation measures would help to alleviate the noise
impacts, some of these measures have not be included in the quantitative
assessment as discussed in the following sections. This would ensure a more conservative assessment.
Detailed
descriptions of these mitigation measures are given in the following
sections.
Good Site
Practices and Noise Management Techniques
Good site
practice and noise management techniques could considerably reduce the noise
impact from construction site activities on nearby NSRs. The following measures
should be followed during each phase of construction:
·
only
well-maintained plant should be operated on-site and plant should be serviced
regularly during the construction programme;
·
machines
and plant (such as trucks, cranes) 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, where possible, be orientated so
that the noise is directed away from nearby NSRs;
·
silencers
or mufflers on construction equipment should be properly fitted and maintained
during the construction works;
·
mobile
plant should be sited as far away from NSRs as possible and practicable; and
·
material
stockpiles, site office and other structures should be effectively utilised,
where practicable, to screen noise from on-site construction activities.
The benefits
of these techniques can vary according to specific site conditions and
operations. The environmental noise climate would certainly be improved through
these control practices, although the improvement can only be quantified during
implementation when specific site parameters are known. The assessment has
therefore not taken into account the effectiveness of “Good Site Practices and
Noise Management Techniques”.
Use of Site
Hoarding
Purpose built
temporary noise barriers (approximately 2.5m high) located on the site
boundaries between noisy construction activities and NSRs could generally
reduce noise levels at low-level zone of NSRs through partial screening. In
general, this would provide a minimum of 5 dB(A) attenuation for the low level
receivers. It would be possible for the Contractor to provide these in the form
of site hoardings to achieve this attenuation effect, provided that the
barriers have no openings or gaps. Good site practice shall also be adopted by
the Contractor to ensure the conditions of the hoardings are properly
maintained throughout the construction period. As a conservative assumption,
however, the site hoarding has not been taken into consideration in the
construction noise assessments.
Use of Temporary Movable Noise Barrier & Enclosure
(with Sufficient Ventilation) for Relatively Static Plant
Movable
temporary noise barriers that can be located close to noisy plant and be moved
concurrently with the plant along a worksite can be very effective for
screening noise from NSRs. A typical design which has been used locally is a
wooden framed barrier with a small-cantilevered on a skid footing with 25mm
thick internal sound absorptive lining. This measure is particularly effective
for low level zone of NSRs. A cantilevered top cover would be required to
achieve screening benefits at upper floors of NSRs.
Movable
barriers will be used for some PME (e.g. pipe pile rigs, auger). It is anticipated
that suitably designed barriers could achieve at least 5 - 10dB(A) reduction.
For a conservative approach, only a reduction of 5dB(A) is assumed. Acoustic
mat will be used for other plant items such as trench cutter, piling,
oscillator and drilling rig and a 10 dB(A) noise reduction is anticipated. This
assumption has been adopted in other approved EIA Reports.
The use of
enclosure (with sufficient ventilation) has been considered in this assessment
to shelter relatively static plant including air compressor, generator. The
enclosures barriers can provide about 10dB(A) noise reduction. For electric
saw, movable noise barriers of 5dB(A) attenuation have been assumed.
A
summary of the temporary movable barriers and enclosures adopted for various
PMEs, and the associated noise reduction is given in Appendix 8.4.
Large Full
Enclosure for Construction Site
Another
possible mitigation measures is the use of large full enclosure for
construction site during cut-&-cover tunnel and station construction. A
larger enclosure for the construction site would provide better noise
attenuation than the use of temporary noise barriers/ acoustic mats. However,
the height of the enclosure would need to be at least 9m in order to
accommodate all the plant. Given the nature of construction works, having such
a tall barrier would impose adverse visual impacts to the neighbouring
receptors and pedestrians. Together with potential nuisance/ impacts on the
access, the use of large enclosure for construction site would cause
significant impacts and hence is not recommended.
Use of “Quiet”
Plant and Working Methods
The use of
quiet plant is a feasible solution to tackle adverse noise impacts associated
with construction works. It is generally known (supported by field measurement)
that particular models of construction equipment are quieter than standard
types given in the TM-GW. Whilst it is
generally considered as too restrictive to specify the specific models or items
of plant to be used by the Contractor, it is reasonable and practicable to set
plant noise performance specifications for specific PME so that some
flexibility in selection of plant is allowed. A pragmatic approach would be to
request that the Contractor to independently verify the noise level of the
plant proposed to be used and demonstrates the plant proposed to be used on the
site meets the requirements through furnishing of the results.
The use of
quiet plant associated with the construction works is prescribed in British
Standard “Noise Control on Construction and Open Sites, BS5228: Part 1: 2009”
which contains the SWLs for specific quiet PME. It should be noted that while
various types of silenced equipment could be found in
A summary of
the “Quiet” PMEs adopted and the associated SWLs is given in Appendix 8.4.
Sequencing
Operation of Construction Plant Equipment
In practice,
some plant items will operate sequentially within the same work site, and
certain reduction of the predicted noise impacts could be achieved. However,
any additional control on the sequencing of plant will impose constraint to the
Contractor on the operation and planning of plant items, and the implementation
of the requirement would be difficult to be monitored. Hence, sequencing
operation of PME has not been taken into consideration in the construction
noise assessments
8.5.7 Assessment Results - Mitigated
Scenario
With the implementation of the
abovementioned mitigation measures, the construction noise levels at the affected
NSRs are predicted and presented in the following tables. The predicted noise
levels at all the NSRs would comply with the corresponding noise criteria. Appendix 8.7E to Appendix 8.10E present
the monthly unmitigated noise contribution during the construction period. Appendix 8.7F to Appendix 8.10F
also present the predicted mitigated construction noise levels at selected
representative NSRs.
Appendices 8.10G, 8.10I and 8.10J presents the details of the mitigated
construction noise assessment near DIH. Table 8.13 below presents the
mitigated noise levels at NSRs.
Table 8.13: Predicted Maximum Mitigated Construction Noise
Levels at Noise Sensitive Receivers
|
NSR
ID |
NSR
Description |
Uses |
Criterion [1] dB(A) |
Mitigated Noise Level [2] dB(A) |
Exceedance dB(A) |
|
Works Area – HUH and HHS |
|||||
|
HUH-1-3 |
|
R |
75 |
62 |
0 |
|
HUH-3-1 |
|
R |
75 |
70 |
0 |
|
HUH-3-2 |
|
R |
75 |
68 |
0 |
|
HUH-4-1 |
|||||
|
The
|
S |
75 |
73 |
0 |
|
|
HUH-4-2 |
The
|
S |
75 |
73 |
0 |
|
HUH-8-1 |
No.
2, |
R |
75 |
65 |
0 |
|
HUH-10-1 |
Harbourfront
Horizon |
C + S |
75 |
72 |
0 |
|
Works Area – KAT |
|||||
|
KAT-P1-5-A |
Residential
premises near KAT |
R |
75 |
61[5] |
0 |
|
KAT-P1-5-B |
Residential
premises near KAT |
R |
75 |
75 |
0 |
|
KAT-P1-5-C |
Residential
premises near KAT |
R |
75 |
62 |
0 |
|
KAT-P1-5-D |
Residential
premises near KAT |
R |
75 |
66 |
0 |
|
KAT-P1-6 |
Residential
premises near KAT |
R |
75 |
65 |
0 |
|
Works Area – DIH |
|||||
|
DIH-9-1 |
Shek
On Building |
E + W |
70 (65) |
63 |
0 (0) |
|
DIH-10-1 |
Hong
Kong Sheung Keung Hui Nursing Home |
H |
75 |
62 |
0 |
|
DIH-11-1 |
Lung
|
R |
75 |
74 |
0 |
|
DIH-12-1 |
Galaxia
Tower B |
R |
75 |
69[3] |
0 |
|
DIH-12-2 |
Galaxia
Tower E |
R |
75 |
74[3] |
0 |
|
DIH-13-1 |
|
E |
70 (65) |
61 |
0 |
|
DIH-14-1 |
|
R |
75 |
66[4] |
0 |
|
DIH-14-3 |
|
R |
75 |
55[4] |
0 |
|
DIH-14-4 |
|
E |
70 (65) |
64[4] |
0 (0) |
|
DIH-14-5 |
|
R |
75 |
65[4] |
0 |
|
DIH-15-1 |
Choi Hung Estate - Kam Wan
House |
R |
75 |
60[4] |
0 |
|
DIH-15-2A |
Choi
Hung Estate - Pik Hoi House |
R |
75 |
63[4] |
0 |
Notes:
[1] Values in parentheses indicate the
noise criterion during examination period of educational institution.
[2] Bolded
values mean exceedance of the noise criteria.
[3] Cumulative
impact arisen from Tsz Wan Shan Pedestrian Link is considered.
[4] Cumulative
impact arisen from SCL (TAW-HUH) near DIH is considered.
[5] Cumulative
impact arisen from SCL (TAW-HUH) near DIH (Appendix 8.10J)
and KAT (Appendix
8.9F) is included.
Results show
that with the implementation of mitigation measures, the construction noise
impact due to the Project alone during non-restricted hours would comply with
the noise criterion of 75dB(A) for residential premises and 70 / 65dB(A) for
educational institutions during normal or examination period respectively.
8.5.8 Assessment Results – Cumulative
Construction Noise with Concurrent Projects
Amongst the NSRs considered, some of them would experience cumulative
construction noise impacts from other concurrent projects (see Section 8.3). All NSRs identified in the vicinity of HHS
and HUH would experience cumulative impact from the Project, SCL (MKK-HUH), SCL
(HUH-ADM), SCL (TAW-HUH) and KTE with EPIW. Table 8.13a presents a summary of
cumulative noise levels at NSRs and details of the calculation are given in Appendix
8.8A and Appendix 8.8B.
Table 8.13a: Predicted Mitigated Cumulative Construction
Noise Levels at Noise Sensitive Receivers
Notes:
[1] Construction noise
levels are predicted based on the programmes of different projects.
[2] Bolded values mean exceedance of the noise criteria.
[3] SCL (MKK-HUH) & SCL
(HUH-ADM).
[4] SCL (TAW-HUH).
[5] Cumulative impacts
arisen from EPIW are included.
Most of the
cumulative construction noise levels at the NSRs would comply with the TM-EIAO
criteria except for HUH-1-3 which would experience exceedance of 3 dB(A).
Residual Cumulative Impacts Exceeding the Construction Noise Criterion
From the above table, the cumulative
noise impact at Wing Fung Building (HUH-1-3) is 78dB(A) with a maximum of
residual impacts exceeding the construction noise criterion of 3dB(A). The noise impact due to the Project is only
62dB(A) which comply with the NCO
daytime construction noise criterion. Residual cumulative impact exceeding the
construction noise criterion would be contributed from the construction
activities of SCL (TAW-HUH). However, the EIA study of SCL (TAW-HUH) indicated
that all practicable mitigation measures have been fully explored and exhausted
to reduce the noise impact arising from construction activities of SCL
(TAW-HUH).
The magnitude of the residual
impacts has been assessed in accordance with Section 4.4.3 of the EIAO-TM in Table
8.14 below.
Table 8.14: Assessment of Residual Impacts from Construction
Noise
|
Criteria |
Assessments |
|
Effects on public health and health of biota or
risk to life |
The extent of noise nuisance would be unlikely
to induce public health concern |
|
Magnitude of the adverse environmental impacts. |
Residual impacts exceeding the construction noise
criterion of between 1-3dB(A) could occur at 1 NSR during the construction
phase based upon worse case scenarios. |
|
Geographic extent of the adverse environmental
impacts. |
The geographic extent of the adverse impacts
from noise will not be large and is anticipated to be limited to within about
10m from the Project works area. |
|
Duration and frequency of the adverse
environmental impacts |
The construction noise impacts of the Project will
be from 1 to 8 months for the affected residential premises; and are,
therefore, temporary and reversible. |
|
Likely size of the community or the environment
that may be affected by the adverse impacts |
Minimal size of the community would be affected,
and therefore be considered acceptable. |
|
Degree to which the adverse environmental
impacts are reversible or irreversible. |
Construction phase impacts should be reversible.
|
|
Ecological context. |
Not Applicable |
|
Degree of disruption to sites of cultural
heritage. |
Not Applicable |
|
International and regional importance. |
The impacts are localized and not of
international and regional importance. |
|
Likelihood and degree of uncertainty of adverse environmental
impacts. |
The impacts predicted are based upon worst case
assumptions and as such, would not occur to the extent predicted on all
occasions. However, the assessment has been made using approved mathematical
modelling techniques and the degree of certainty on the results is high. |
Housing Authority
Development Sites 1A & 1B
As discussed in Section 1, the construction of the Housing Authority Development
Sites 1A and 1B (i.e. KAT-P1-5-A, KAT-P1-5-B, KAT-P1-5-C, KAT-P1-5-D and
KAT-P1-6) would be concurrent with the construction of the KAT for about 1 year
since the intake year for Sites 1A and 1B would be occurred in October
2012.
However, the site formation of the
Sites 1A and 1B have been completed, the noise impacts caused by these superstructure
works on the nearest receivers at
Other
Infrastructure Development within Kai Tak Development
As discussed in Section 1, the construction of some of the other infrastructure
development within Kai Tak Development would be concurrent with the
construction of the KAT. However, the
site formation of these infrastructure have been completed, the noise impacts
caused by these superstructure works on the nearest receivers at Rhythm Garden,
Choi Hung Estate and residential premises near KAT (i.e. KAT-P1-5-A,
KAT-P1-5-B, KAT-P1-5-C, KAT-P1-5-D and KAT-P1-6) at more than 920m, 730m, 620m,
840m and 490m respectively away would not be significant as compared to the construction noise
generated by the construction of KAT.
Besides, it is anticipated that the project proponent of other
infrastructure developments would implement effective good site practices such
as quiet plant and temporary movable noise barriers for some of the mobile PME.
Therefore, the cumulative construction noise impacts due to the construction of
other infrastructure development within Kai Tak Development would not be
significant.
8.6.1
Operational
Airborne Noise Source
The KAT, DIH
are underground stations and HUH will be covered by the existing podium. The alignment near to DIH would be in the
form of a tunnel. Therefore, there would
not be any adverse airborne noise impact resulting from their operation.
The HHS fan
and other associated launching and retrieval tracks for connecting the stabling
sidings to the SCL (TAW-HUH) alignment will extend outside the north and south
of the podium. These tracks would be in the form of non-ballast or ballast at-grade tracks which are
exposed and may result in airborne train noise impacts at nearby NSRs. As a conservative approach, non-ballast
tracks were assumed for these tracks in the assessment.
The emergency
tracks of HHS would need to connect to the tracks for the new SCL (TAW-HUH),
this would require removal of a short length of trough wall as compared with
the design assessed under the SCL(TAW-HUH) EIA.
This modification has been considered in the calculation of airborne
train noise impacts from SCL (TAW-HUH) during cumulative impact assessment.
The
ventilation system required for operation of stations and stabling sidings
would be fixed noise sources that needs to be considered.
8.6.2
Noise
Sensitive Receivers
Among the NSRs identified in Section 8.4.1, the NSRs that would be affected by operation of the
Project are summarized in Table
8.15. The Area Sensitive
Ratings and the night-time assessment goal, which is the most critical period
for operational train noise assessment, are summarised in Table
8.15.
Table 8.15: Summary of noise sensitive receivers and
area sensitivity ratings
|
NSR ID |
NSR Description |
Type [2] |
ASR |
Assessment Goal |
|
HUH-1-3 |
|
R |
C |
50[1] |
|
HUH-3-1 |
Block
2, |
R |
C |
50[1] |
|
HUH-4-1 |
Tower
2, The Metropolis Residence[3] |
S |
B |
45[1] |
|
HUH-4-2 |
Tower
1, The Metropolis Residence[3] |
S |
B |
45[1] |
|
HUH-8-1 |
|
R |
C |
50[1] |
|
HUH-10-1 |
Harbourfront
Horizon[4] |
C + S |
B |
55 |
Notes:
[1] A 10dB(A) is assumed as
the noise contribution from existing East Rail Line and Intercity Train. To take into account the cumulative airborne
noise impacts from the existing East Rail Line and Intercity Train, an assessment
goal of ANL – 10 dB(A) is adopted.
[2] R–
Residential; S – Service Apartment; C – Commercial
[3] Metropolis
Residence is a service apartment and shall not rely on openable windows for
ventilation. Nonetheless, for conservative consideration that occupier might
open window under special circumstances, this premise has been considered as an
assessment point.
[4] Harbourfront
Horizon shall not rely on openable windows for ventilation. Nonetheless, for
conservative consideration that occupier might open window under special
circumstances, this premise has been considered as an assessment point.
8.6.3 Assessment Methodology – Operational
Noise
8.6.3.1
Railway Noise
The proposed methodology
for predicting the airborne train noise impacts is given below.
Arup’s train
noise model (OveRail) will be used to predict and assess the propagation of airborne train noise. The modelling methodology for propagation is based on the prediction
procedures in Calculation of Railway Noise 1995 (CRN)[8-8] and it has been validated against the examples listed in CRN handbooks.
Whilst the
propagation model would be based on CRN, the train noise (both rolling noise
and A/C noise) source term would base upon the noise level measured during the
commissioning of SP1900 train[8-9] and is based on a disc braked
Electric Multiple Unit (EMU). The source
term measurement report is given in Appendix 8.11. A description
of the noise source term is given below.
|
Parameters |
On Ballast Track |
|
Lmax |
75.3 dB(A) |
|
Rail |
Continuously weld rail |
|
Trackform |
Ballasted track |
|
Speed |
130kph |
|
Distance |
25m |
|
The calculation of SEL (single train event) from Lmax
is based on the following equation |
|
|
SEL = Lmax + 10 log (L/V)
+10.5 –10 log (4D / (4D2+1) + 2 tan-1
(1/2D)) Where
L = train length, m (200m for SCL (TAW-HUH)
train, the same as MOL 8-car configuration) V = train speed, kph d = Distance from track, m (reference distance at 25m) D = d / L |
|
|
SEL for 8 car |
82.7 dB(A) |
For non-revenue
trains (e.g. engineering trains) of HHS, noise will also be generated by
rolling stock operating during the non-revenue hours of the railway typically
between 0200 and 0500. These will be used to support maintenance operations in
the transporting of personnel and plant for inspection and remedial works.
As overhead line power supply may need to be turned off for safety and
other requirements, the rolling stock will be independently powered
locomotives. These will typically trail a short rake of wagons or
self-propelled ballast tamping machines and rail grinding apparatus.
Noise from non-revenue
trains would be governed by Construction Noise Permit and hence would not be
quantified in this EIA.
The tracks would be
modelled as segments such that the variation of noise contribution within the
track segment is less than 2 dB(A), which is in line with CRN. For each segment, corrections would be
applied to compute its noise contribution to NSRs. The total noise levels at receivers would
then be computed by combining the noise contributions from all the segments.
Along the launching tracks and the north fan area to the north and south
of HHS respectively, 6 trains/direction/hour are assumed during the nighttime
period. For train shunting along the
section between Hung Hom bypass and
A summary of other
correction factors to be included in the airborne train noise prediction model
is given below.
Table 8.16: Summary of correction factors
|
Parameters |
Assumptions |
Remarks |
|
Rail deterioration |
+3dB(A) |
The source term measurement was taken with
typical rail condition. The adopted +3
dB(A) correction is a conservative approach to account for the deviation from
typical rail condition. |
|
Train speed |
Change of SEL with speed = 20 log (V / Vref)
dB(A) |
V and Vref are the average
train speeds Maximum train speed within HHS is 25kph; Maximum train speed for SCL (TAW-HUH) near HHS is
50kph. |
|
Distance |
Change of Lmax with distance = 10 log
(d1 / 25) dB(A) |
d1 is the distance
between track and receiver |
|
Deck Reflection |
· At-Grade non-ballast track = 2.5 dB(A) |
Consistent with MOL[8-10] |
|
Barrier effects |
As per Chart 6(a) of CRN[8-8] |
|
|
Joints / Crossovers |
7dB(A) |
To represent the augmentation
in noise due to thermal expansion joints. Average value of 5 dB(A) is
summarised in Ref. [8-11]. A conservative
correction of 7 dB(A) which is consistent with MOL[8-10] EIA is
adopted. 2m long rail segment is used to represent a joint. |
|
Air absorption |
0.2 – 0.008d |
|
|
Train Frequency |
10log(N1) |
N1 is the train frequency in 30 minutes Frequency (trains / direction / 30 minutes) 24/12 trains per hour in each direction during daytime/nighttime for
the main alignment of SCL(TAW-HUH) 6 trains per hour in each direction during daytime/nighttime along the
launching/retrieval tracks extending to the north and south of the podium |
|
View Angle |
10 log (πθ/180-cos2α sinθ) – 5 dB(A) |
α is the acute angle between a line drawn through
the receiver point, parallel to the track and the line bisecting the angle
view θ. θ is the view
angle. |
|
Façade Reflection |
2.5dB(A) |
|
|
To Leq, 30 min |
10 log( 1 / 1800) |
|
Cumulative
Airborne Railway Noise Impacts
The surrounding
environmental at Hung Hom has been reviewed.
There would be cumulative air-borne train noise impacts at the following
locations.
|
Location |
Cumulative Train Noise Sources |
|
Hung Hom |
·
Existing East Rail within HUH |
|
|
·
SCL (TAW – HUH) ·
SCL (MKK – HUH) |
Following the opening of
HHS, the cumulative noise impact from East Rail Line have been addressed by considering
an assessment goal of 10 dB(A) lower than the ANL. This approach would ensure that noise
contribution from the operation of HHS is insignificant and is considered
appropriate for NSRs which would experience noise impact from existing East
Rail Line and Intercity Train. Appendix 8.12 shows the typical section of the
alignment of HHS.
8.6.3.2
Fixed Noise Sources
Noise Sources
A summary of key fixed
noise sources within the SCL (HHS) include:
·
Ventilation
systems for stabling sidings at Hung Hom Freight Yard;
·
Ventilation
systems for KAT and DIH;
·
Ventilation
systems for the HUH.
All the noise
sources (see Figure 8.2.1 to
Figure 8.2.3 for locations) mentioned above would be
accommodated inside solid buildings with louvers. Maximum allowable
Sound Power Level (SWL) for above-grade louvers will be established by
considering the following:
·
Separation
distances and orientation from the nearest NSR(s); and
·
Cumulative noise
impacts from noise sources of concurrent projects(e.g. cooling
Assessment Methodology
The following
general procedures have been adopted for the operation noise assessment.
·
Identify and locate representative NSRs that
may be affected by the noise sources;
·
Determine the noise criteria for both daytime
and nighttime;
·
Use standard acoustic principle for
attenuation and directivity;
·
Determine the maximum sound power levels
(SWLs) of the fixed noise sources;
8.6.4
Assessment
Results – Operational Phase
8.6.4.1
Railway Noise – Night-time Noise Impacts
The NSRs near HHS would be affected by the train running on tracks. Assessment results indicate that the
unmitigated impact would be 4 dB(A) above the assessment goal for some NSRs
(Refer to Table 8.17).
It is therefore necessary to consider mitigation measures to reduce the noise
impacts from the operation of HHS. The following mitigation measures
were proposed:
·
7m high semi-enclosure extending from the edge
of the podium to the realigned Cheong Wan Road (P1) Bridge with a structural separation to
allow independent movement between the two structures;
·
Approximate 35m long of noise barrier at a
height of 5m from Cheong Wan Road towards north (P2); and
·
Approximate 45m long of noise barrier at a
height of 5m from
Note: Height of noise barrier
is measured from the track level.
The extent
and location of the mitigation mentioned above are shown in Appendix 8.13. The
proposed semi-enclosure mentioned above will also need to achieve operational
ventilation requirements. The noise enclosure is open-sided towards the west and also incorporates openings in the roof to provide natural
ventilation provisions. The design of
the roof
openings
will
ensure that there is no line of sight from the neighbouring sensitive
receivers to the tracks in the north fan area. Exact dimension of the structural separation
to be determined during detailed design stage.
The
predicted daytime and night-time noise levels are summarised in Table 8.17a and Table 8.17b
respectively.
Table 8.17a: Summary of predicted night-time railway noise levels for NSRs at Hung Hom
|
Noise Sensitive Receivers |
Predicted
Unmitigated Noise Level, dB(A) |
Predicted
Mitigated Noise Level, dB(A) |
Predicted
Cumulative Noise Level, dB(A) – Mitigated Scenario |
Assessment
Goal, dB(A) |
||||
|
The
Project |
SCL
(TAW-HUH) [2] |
SCL
(MKK-HUH) |
The
Project |
SCL
(TAW-HUH) [2] |
SCL
(MKK-HUH) |
|||
|
HUH-1-3
|
53 |
40 |
35 |
47 |
40 |
35 |
48 (1/F) |
50[1]
|
|
HUH-3-1 |
47 |
48 |
- |
37 |
48 |
- |
48 (29/F) |
50[1]
|
|
HUH-4-1
|
40 |
43 |
- |
13 |
43 |
- |
43 (1/F) |
45[1]
|
|
HUH-8-1 |
41 |
47 |
- |
38 |
47 |
- |
47 (1/F) |
50[1]
|
|
HUH-10-1 |
38 |
47 |
- |
38 |
47 |
- |
47 (1/F) |
55 |
Note: [1]
A 10 dB(A) has been deducted from the
ANL to take into account noise level from the East Rail Line and Intercity
Train.
[2] The tracks to both north and south of HHS
would need to connect to the tracks for new SCL (TAW-HUH). This has also been taken
into account in the assessment.
Table 8.17b: Summary of predicted daytime railway noise levels
for NSRs at Hung Hom
|
Noise Sensitive Receivers |
Predicted
Unmitigated Noise Level, dB(A) |
Predicted
Mitigated Noise Level, dB(A) |
Predicted
Cumulative Noise Level, dB(A) – Mitigated Scenario |
Assessment
Goal, dB(A) |
||||
|
The
Project |
SCL
(TAW-HUH) [2] |
SCL
(MKK-HUH) |
The
Project |
SCL
(TAW-HUH) [2] |
SCL
(MKK-HUH) |
|||
|
HUH-1-3
|
53 |
43[3] |
36 |
47 |
43[3] |
36 |
49 (1/F) |
60[1]
|
|
HUH-3-1 |
47 |
51[3] |
- |
37 |
51[3] |
- |
51 (29/F) |
60[1]
|
|
HUH-4-1
|
40 |
46[3] |
- |
13 |
46[3] |
- |
46 (1/F) |
55[1]
|
|
HUH-8-1 |
41 |
50[3] |
- |
38 |
50[3] |
- |
50 (1/F) |
60[1]
|
|
HUH-10-1 |
38 |
50[3] |
- |
38 |
50[3] |
- |
50 (1/F) |
65 |
Note: [1]
A 10 dB(A) has been deducted from the ANL
to take into account noise level from the East Rail Line and Intercity Train.
[2] The tracks to both north and south of HHS
would need to connect to the tracks for new SCL (TAW-HUH). This has also been
taken into account in the assessment.
[3] In SCL (TAW-HUH) EIA Report, 24
trains/direction/hour is assumed for the noise assessment. In addition, a
sensitivity test has been conducted to examine the noise effect if the train
frequency is increased in the future operation. As compared with the predicted
daytime noise levels based on the assumption of 24/trains/direction/hour, an
increase of 0.3 dB(A) and 0.7 dB(A) would be predicted respectively for 26 and
28 trains/direction/hour. Hence, the predicted noise levels of SCL (TAW-HUH)
would still comply with the noise criterion even if 26 or 28
trains/direction/hour during day time periods are adopted.
Prior to the operational phase of the Project, a
commissioning test will be conducted for verification of EIA predictions against
the assessment goals and checking the compliance of the airborne noise levels
with the NCO noise criteria.
8.6.4.2
Railway Noise – Maximum Noise Level Lmax
As presented
in Section 8.6.3.1, the reference
maximum noise level (Lmax) is 75.3 dB(A), for train speed of 130km/h
and measured at 25m from track. This
noise level is significantly lower than the statutory requirement of 85
dB(A). Among the identified NSRs, the
setback distance is more than 25m and the train speed is about 25km/h. This setback distance is the same as that
with the reference condition and operating speed of the trains are
substantially lower than the reference condition.
In consideration of the above comparison, exceedance of the statutory
maximum noise level is not anticipated along the alignment.
8.6.4.3
Railway Noise – 24-Hour Average Noise Level Leq, 24 hour
Detailed schedule timetable is not available at the
time of reporting. Based on available
information, headway over 24 hours along the launching/retrieval tracks, the
north fan area and shunt neck would not be more than 100 trains. Based on this assumption, the predicted
24-hour average railway noise levels would comply with the Leq, 24hr
criterion and are summarized in Appendix
8.13A.
8.6.4.4
Fixed Noise Sources
Assessment has been
conducted to evaluate the maximum Sound Power Level (SWL) for the ventilation
shafts in HHS, HUH, KAT and DIH. Locations of assessment point for fixed noise sources are shown in Figure 8.2.1 to 8.2.3.
The predicted maximum allowable SWL is summarised in Table 8.18 below.
Detailed calculations are presented in Appendix 8.14.
Table 8.18 : Maximum Allowable SWL for the
Ventilation Building and Ventilation Shafts
|
Station/Location |
Plant Item |
Plant ID |
Maximum allowable Sound Power Level, dB(A) |
Remarks |
|
|
Daytime |
Night-time |
||||
|
HHS and HUH |
Ventilation Shaft |
HHS VS1 |
92 |
82 |
|
|
|
|
HHS VS2 |
91 |
81 |
|
|
|
|
HHS VS3 |
91 |
81 |
|
|
|
|
HHS VS4 |
91 |
81 |
|
|
|
|
HHS VS5 |
85 |
75 |
|
|
|
|
HHS VS6 |
86 |
76 |
|
|
|
|
HHS VS7 |
85 |
75 |
|
|
|
|
HHS VS8 |
85 |
75 |
|
|
|
|
HHS VS9 |
86 |
76 |
|
|
|
|
HHS VS10 |
86 |
76 |
|
|
|
|
HHS VS11 |
88 |
78 |
|
|
|
|
HHS VS12 |
85 |
75 |
|
|
|
|
HHS VS13 |
85 |
75 |
|
|
|
|
HHS VS14 |
88 |
78 |
|
|
|
|
HHS VS15 |
88 |
78 |
|
|
|
|
HUH VS7 |
96 |
86 |
|
|
|
|
HUH VS8 |
96 |
86 |
|
|
|
|
HUH VS9 |
96 |
86 |
|
|
|
|
HUH VS10 |
96 |
86 |
|
|
|
|
HUH VS11 |
96 |
86 |
|
|
|
|
HUH VS12 |
96 |
86 |
|
|
|
|
HUH VS13 |
95 |
85 |
|
|
|
|
HUH VS14 |
95 |
85 |
|
|
|
|
HUH VS15 |
99 |
89 |
|
|
|
|
HUH VS16 |
94 |
84 |
|
|
|
|
HUH VS17 |
94 |
84 |
|
|
|
|
HUH VS18 |
96 |
86 |
|
|
|
|
HUH VS19 |
97 |
87 |
|
|
|
|
HUH VS20 |
95 |
85 |
|
|
|
|
HUH VS21 |
96 |
86 |
|
|
|
|
HUH VS22 |
95 |
85 |
|
|
|
|
HUH VS23 |
94 |
84 |
|
|
KAT |
Ventilation Shaft |
VS - KAT - 1 - 1 |
95 |
85 |
|
|
|
|
VS - KAT - 1 - 4 |
95 |
85 |
|
|
|
|
VS - KAT - 1 - 5 |
95 |
85 |
|
|
|
|
VS - KAT - 2 - 1 |
94 |
84 |
|
|
|
|
VS - KAT - 2 - 2 |
94 |
84 |
|
|
|
|
VS - KAT - 2 - 3 |
94 |
84 |
|
|
|
|
VS - KAT - 2 - 4 |
94 |
84 |
|
|
|
|
VS - KAT - 2 - 5 |
94 |
84 |
|
|
|
|
VS - KAT - 3 - 5 |
90 |
80 |
|
|
|
|
VS - KAT - 4 - 5 |
89 |
79 |
|
|
|
|
VS - KAT - 5 - 1 |
89 |
79 |
|
|
|
|
VS - KAT - 5 - 2 |
89 |
79 |
|
|
|
|
VS - KAT - 5 - 3 |
89 |
79 |
|
|
|
|
VS - KAT - 5 - 5 |
89 |
79 |
|
|
|
|
VS - KAT - 6 - 1 |
89 |
79 |
|
|
|
|
VS - KAT - 6 - 3 |
89 |
79 |
|
|
|
|
VS - KAT - 6 - 4 |
89 |
79 |
|
|
|
|
VS - KAT - 6 - 5 |
89 |
79 |
|
|
|
|
VS - KAT - 7 - 1 |
88 |
78 |
|
|
|
|
VS - KAT - 7 - 2 |
84 |
74 |
|
|
|
|
VS - KAT - 7 - 3 |
90 |
80 |
|
|
|
|
VS - KAT - 7 - 4 |
90 |
80 |
|
|
|
|
VS - KAT - 7 - 5 |
85 |
75 |
|
|
DIH |
Ventilation Shaft |
VS - DIH - 1 |
83 |
73 |
|
|
|
|
VS - DIH - 2 |
82 |
72 |
|
|
|
|
VS - DIH - 3 |
82 |
72 |
|
|
|
|
VS - DIH - 4 |
78 |
68 |
|
|
|
|
VS - DIH - 5 |
82 |
72 |
|
|
|
|
VS - DIH - 6 |
84 |
74 |
|
|
|
|
VS - DIH - 7 |
82 |
72 |
|
|
|
|
VS - DIH - 8 |
92 |
82 |
|
|
|
|
VS - DIH - 9 |
85 |
75 |
|
|
|
|
VS - DIH - 10 |
94 |
84 |
|
|
|
|
VS - DIH - 11 |
83 |
73 |
|
|
|
|
VS - DIH – 12 |
86 |
76 |
|
|
|
|
VS - DIH – 13 |
77 |
67 |
|
|
|
|
VS - DIH – 14 |
75 |
65 |
|
|
|
|
VS - DIH – 15 |
79 |
69 |
|
|
|
|
VS - DIH – 16 |
92 |
82 |
|
|
|
|
VS - DIH – 17 |
85 |
75 |
|
|
|
|
VS - DIH – 18 |
80 |
70 |
|
|
|
|
VS - DIH – 19 |
85 |
75 |
|
|
|
|
VS - DIH – 20 |
90 |
80 |
|
|
|
|
VS - DIH - 21 |
83 |
73 |
|
|
|
|
VS - DIH - 22 |
78 |
68 |
|
|
|
|
VS - DIH – 23 |
83 |
73 |
|
|
|
|
VS - DIH – 24 |
88 |
78 |
|
|
|
|
VS - DIH – 25 |
81 |
71 |
|
|
|
|
VS - DIH – 26 |
81 |
71 |
|
|
|
|
VS - DIH – 27 |
85 |
75 |
|
|
|
|
VS - DIH – 28 |
92 |
82 |
|
|
|
|
VS - DIH – 29 |
85 |
75 |
|
|
|
|
VS - DIH – 30 |
78 |
68 |
|
|
|
|
VS - DIH – 31 |
87 |
77 |
|
|
|
|
VS - DIH – 32 |
92 |
82 |
|
|
|
|
VS - DIH – 33 |
87 |
77 |
|
|
|
|
VS - DIH – 34 |
80 |
70 |
|
The equipment should be
free of the characteristics of tonality, impulsiveness and intermittency. If the selected equipment could not be free
of characteristics of tonality, impulsiveness and intermittency, the maximum SWL
should be reduced in accordance with the correction factors, in the range of 3
to 6 dB(A), as given in Section 3.3 of TM-IND.
The contractor shall
install acoustic silencers, noise barriers, acoustic louvers where appropriate
to ensure that the specified maximum SWLs shown in Table
8.18 will not be exceeded.
8.6.5
Mitigation
Measures
8.6.5.1
Operational Phase
The detailed design should incorporate the following good practice in order
to minimise the nuisance on the neighboring NSRs. In case the Contractor would
change the design and locations of the vents, they would need to comply with
the legislative maximum impacts at the receivers.
·
Louvers should be orientated away from adjacent
NSRs, preferably onto main roads which are less sensitive.
·
Direct noise mitigation measures including
silencers, acoustic louvers and acoustic enclosures should be allowed for in
the design for the ventilation shafts, stations and stabling sidings.
·
The façade
for these plant areas/ ventilation shafts should have adequate sound insulation
properties to minimise the noise emanating through the building fabric.
8.6.5.2
Residual Impacts exceeding the operational
noise criterion and Constraints on Future Receivers
The operational noise generated by the proposed railway can be properly
mitigated by implementing the proposed mitigation measures. Adverse residual
impacts exceeding the operational noise criterion are not anticipated and no
constraints could be identified on the future sensitive receivers at this
stage.
Construction noise assessment has been conducted. Results indicate that the noise impacts after
implementation of mitigation measures, including good site, optimisation of
construction methodology (i.e. schedule of using PME), quiet plant, temporary
noise barrier, enclosure and acoustic mat, the construction noise impacts due
to the Project are within the noise criterion at all sensitive receivers.
Airborne train noise assessment has been conducted. Mitigation measures including noise barrier
and semi-enclosure were recommended for the open at-grade tracks. With the recommended mitigation measures in
place, the predicted airborne train noise levels at nearby NSRs would comply
with the noise criteria.
Maximum sound power levels allowed to be emitted from each fixed noise
source were predicted. Good practice
should be included in the detail design to ensure compliance with the NCO and
other planning requirements.
[8-1] Noise Control Ordinance (Cap 400), HKSAR
dated June 1997.
[8-2] Technical Memorandum on Noise from
Construction Work other than Percussive Piling, EPD dated March 1996.
[8-3] Technical Memorandum on Noise from
Percussive Piling, EPD dated June 1999.
[8-4] Technical Memorandum on Noise from
Construction Work in Designated Areas, EPD dated June 1999.
[8-5] Technical Memorandum on Environmental
Impact Assessment Process (EIA Ordinance), EPD dated September 1997.
[8-6] Technical Memorandum for the Assessment
of Noise from Places Other Than Domestic Premises, Public Places or
Construction Sites.
[8-7] Kwun Tong Line Extension: Environmental
Impact Assessment, MTR Corporation Limited.
[8-8] Calculation of Railway Noise 1995, the
Department of
[8-9] SEL Source Term Measurement, MTR
Corporation Limited.
[8-10] Tai Wai to Ma On Shan Extension:
Environmental Impact Assessment, Kowloon-Canton Railway Corporation, October
1999.
[8-11] “Transportation Noise Reference Book” by P.M. Nelson, published by
Butterworth & Co. (Publishers) Ltd, 1987.