This section provides an evaluation of the noise impacts arising from
the construction and operation of the LNG terminal proposed on
5.2
Legislation
Requirement and Evaluation Criteria
5.2.1
Construction Phase
General
The noise impacts associated with the LNG terminal
construction will be assessed according to the Environmental Impact Assessment Ordinance (Cap.499) and its Technical Memorandum, EIAO-TM. The assessment criteria are defined in Annex 5 of the EIAO-TM and the principal legislation for controlling construction
noise is the Noise Control Ordinance,
Cap. 400 (NCO). A number of technical memoranda (TMs)
have been issued under the NCO to
stipulate control approaches and criteria and those that may be relevant to the
construction of the terminal include the following:
·
Technical
Memorandum on Noise from Construction Work Other than Percussive Piling (GW-TM)
which provides the guidelines for controlling the construction noise from power
mechanical equipment (PME) in general construction works.
·
Technical
Memorandum on Noise from Construction Work in Designated Areas (DA-TM)
which deals with control of noise generated by specified powered mechanical
equipment (SPME) and prescribed construction work (PCW) within designated
areas.
·
Technical
Memorandum on Noise from Percussive Piling (PP-TM)
which addresses the control of noise from percussive piling in addition to
issuance of Construction Noise Permit (CNP).
Percussive Piling
Under the PP-TM, percussive
piling is prohibited at any time on Sundays and public holidays and during
evening and night-time hours (1900 - 0700 hours), Monday through Saturday. A CNP is required in order to carry out
such work during daytime hours (0700 - 1900 hours) Monday through
Saturday. In
addition, percussive piling is prohibited at any time on Sundays and public
holidays and during evening and night-time hours (1900 - 0700 hours), Monday
through Saturday.
As the issuance of a CNP by the Noise
Control Authority would depend on the submission of an application by the
contractor, and therefore on the contractor’s compliance with the percussive
piling noise limits set out within the
PP-TM, the assessment of this type of noise has not been included in this
EIA.
General Construction Works During Restricted Hours
The NCO
provides statutory controls on general construction works during restricted
hours (i.e., 1900 - 0700 hours Monday to Saturday and at any time on Sundays
and public holidays). The use of
PME for carrying out construction works during these restricted hours would
require a CNP. The Noise Control Authority will assess all
CNP applications on a case-by-case basis and, in doing so, the authority
advises that they will be guided by the GW-TM.
When assessing an application for the use of PME, the Noise Control Authority will compare the
Acceptable Noise Levels (ANLs) specified in the GW-TM with the CNLs (adjusted for any barrier and reflection
effects) associated with the proposed PME operations. The NCO
requires that noise levels from construction at affected NSRs be less than the
specified ANL. The ANLs are related
to the inherent noise sensitivity of the noise receiver areas in question,
which in turn relate to the background noise characteristics of these
areas. Each noise receiver area is
then assigned an Area Sensitivity Rating (ASR) based on its predominant land
use and the presence, if any, of Influencing Factors (IFs) such as nearby
industrial areas, major roads or airports.
The relevant ANLs are shown in Table
5.1. Factors influencing the outcome of a CNP application, such as the
assigning of ANLs, would be determined by the Noise Control Authority at the time of the application review based
on the prevailing site conditions which may change from time to time. It should be noted that nothing in this report shall bind the
Noise Control Authority in making
their decision. If a permit is to
be issued, the Authority shall include any condition it thinks fit, and such
conditions shall be followed while the works covered by the permit are being
carried out. Failure to comply with
any conditions could result in the cancellation of the permit and prosecution
action under the NCO.
Table
5.1 Acceptable
Noise Levels (ANLs) for General Construction Works to be carried out during
Restricted Hours
|
Time Period |
Area Sensitivity Rating(a) LAeq, 5 min (dB(A)) |
||
|
A |
B |
C |
|
|
All
days during the evening (1900 - 2300 hours) and general holidays (including
Sundays) during the daytime and evening (0700 - 2300 hours) |
60 |
65 |
70 |
|
All
days during the night-time (2300 - 0700 hours) |
45 |
50 |
55 |
|
Note: (a) The standards apply to uses
which rely on opened windows for ventilation. |
|||
General Construction Works During
Although the NCO
does not provide for the control of noise from construction activities during normal
working hours (0700 - 1900, Monday to Saturday), Annex 5 of the EIAO-TM
specifies a limit of Leq, 30 min 75 dB(A) for residential
NSRs. Annex 5 also provides construction noise limits of Leq, 30
min 70 dB(A) and 65 dB(A) for schools during normal teaching periods and
examination periods respectively.
5.2.2
Operational Phase
Fixed plant noise is controlled under Section 13 of the NCO and the predictions will be undertaken in accordance with the Technical Memorandum on Noise from Places
other than Domestic Premises, Public Places or Construction Sites (IND-TM). The criteria noise limits are set out in
the EIAO-TM as follows:
· The total fixed source
noise level at the facade of the nearest NSR is at least 5 dB(A) lower than the
appropriate ANL (as shown in Table 5.2)
as specified in the IND-TM; or
· Where the
prevailing noise level in the area is 5 dB(A) or more below the appropriate
ANL, the total fixed source noise level must not exceed this noise level.
The criteria noise limits stipulated in the IND-TM apply for all days and general
holidays and are dependent on the Area Sensitivity Rating (ASR) of the NSRs, as
shown in Table 5.2.
Table
5.2 ANLs
to be used as Operational Noise Criteria
|
Time Period |
LAeq
30min (dB(A)) |
||
|
ASR “A” |
ASR “B” |
ASR “C” |
|
|
Daytime (0700 – 1900) |
60 (55) |
65 (60) |
70 (65) |
|
Evening (1900 – 2300) |
60 (55) |
65 (60) |
70 (65) |
|
Night-time (2300 – 0700) |
50 (45) |
55 (50) |
60 (55) |
|
Note: The number in
brackets indicates the noise limit (ANL -5) for operational noise impact
assessment. |
|||
As the site is located in a rural area and no influencing factors affect
the NSRs, which are located at more than 6 km away from the site, an ASR “A”
has been assumed for the NSR located in the vicinity of the proposed site. Baseline noise measurement has been
conducted to investigate the prevailing noise levels at Shek Pik (the nearest
sensitive area) and to establish the noise limit for the assessment of the
operational noise impact. Details
of the noise measurement will be further discussed in Section 5.3.3.
The Area Sensitive Rating assumed in this Report is for an indicative
operational noise assessment only.
It should be noted that fixed noise sources are controlled under Section 13 of the NCO. At the time of
investigation, the Noise Control Authority
shall determine noise impact from concerned fixed noise sources on the basis of
prevailing legislation and practices being in force, and taking account of
contemporary conditions / situations of adjoining land uses.
5.3
Baseline
Environmental Conditions and Noise Sensitive Receivers
5.3.1
Baseline Environmental
Conditions
The area of the proposed site is in an uninhabited rural area. Siu A Chau (North Soko Island) is
located at approximately 1 km away to the north of the proposed site and is now
uninhabited. The background noise
environment is dominated by the noise from marine vessel traffic.
5.3.2
Noise Sensitive Receivers
No NSR has been identified on the islands (South Soko and
An
approximately 40-km long submarine gas pipeline linking the proposed LNG
terminal at the South Soko Island to the existing Black Point Power Station and
gas receiving station (GRS) will be constructed (Figure
5.4a). The installation of the submarine gas
pipeline will use a combination of dredging and jetting methods. The nearest NSRs that may be affected by
the installation of gas pipeline and GRS are identified as the Tai O Barracks
(N2) at Tai O (Figure 5.3b)
and the village house at Lung Kwu
Sheung Tan (N3) (Figure 5.3c) respectively. The village house (N3) at Lung Kwu Sheung is used as an office for the
outdoor karting track, according to the approved EIA Report for Proposed
Karting Track in D.D.134, Lung Kwu Sheung Tan, Tuen Mun (EIA-116/2005). To present a worse case scenario, the
construction noise impact at this village house has also been assessed.
5.3.1
Baseline Noise Measurement
To
investigate the prevailing noise levels at Shek Pik area, two sets of
continuous 24-hour noise measurement were made from 19 to 20 January 2006 at the roof top of Block J of the Staff Quarters (N1a) and at the 4/F of
Block K of Staff Quarters (N1b) from 13 to 14 July 2006 (Figure 5.3d). The noise measurements were conducted
using Solo 01 Premium Sound Level Meter (Type 1) and were calibrated using
B&K Sound Level Calibrator Type 4231 with a calibration signal of 94.0
dB(A) at 1 kHz. The measurements
were conducted with
reference to the calibration and measurement procedures as stated in the IND-TM.
The
measurement results are summarised in Tables 5.3 and 5.4 and timeline charts showing the prevailing noise
levels are presented in Figures 5.3e
and 5.3f.
Table
5.3 Measured
Prevailing Facade Noise Level at N1a
|
Period |
|
LAeq, 30min dB(A) |
|
|
|
Minimum |
Average |
Maximum |
|
0700 – 2300 hours |
51 |
55 |
59 |
|
2300 – 0700 hours |
50 |
52 |
54 |
Table
5.4 Measured
Prevailing Facade Noise Level at N1b
|
Period |
|
LAeq, 30min dB(A) |
|
|
|
Minimum |
Average |
Maximum |
|
0700 – 2300 hours |
54 |
56 |
63 |
|
2300 – 0700 hours |
53 |
55 |
56 |
The minimum measured prevailing noise levels at the Shek Pik Staff
Quarter are in the range of 50 -53 dB(A) during night-time period, which are
higher than the (ANL-5) criterion, and therefore the (ANL – 5) criterion, i.e.,
45 dB(A) LAeq, 30min for the night-time period will be adopted as
the stipulated noise limit for the assessment of operational noise
impacts.
5.4
Potential
Sources of Impacts
5.4.1
Construction Phase
Potential noise sources during the construction phase
of the LNG terminal will mainly arise from PME operating at the construction
work sites. As discussed in Part 1, an LNG terminal located at South
Soko will necessitate the installation of a submarine electricity circuit and a
submarine water supply pipeline from Shek Pik Reservoir in South Lantau to the western shore on South Soko Island, a natural gas pipeline and a Gas
Receiving Station (GRS) located at the existing GRS for the Yacheng Pipeline (Figure
5.4a). The major construction work will include the following
key activities:
·
Land based works at
-
Site clearance;
-
Soil compaction; and
-
Blasting and excavation.
·
Reclamation:
-
Dredging;
-
Seawall construction;
-
Placing fill; and
-
Drainage works.
· Main Jetty works:
-
Ground investigation;
-
Construction of jetties and
access bridge;
-
Dredging of approach channel
and turning basin; and
-
Intake and outfall
construction.
· Civil works at terminal:
-
Civil and structural
construction works for the terminal facilities.
· Installation of Water Main
& Cable
· Installation of Submarine gas
pipeline
· Installation of Gas Receiving
Station:
-
Dredging;
-
Seawall construction; and
-
Placing fill.
The construction noise assessment will be undertaken based on the construction
programme and plant inventories summarised in Annexes 5-B and 5-C
respectively.
The
plant inventory has been checked by Project Proponent and is confirmed to be
practical and feasible to complete the project within the scheduled timeframe
and the PMEs are available in the market.
Liaisons on the blasting
works are being conducted with the Mines Division of GEO and CEDD in the
preparation of the report. No
opencast blasting will be carried out during evening and night-time periods
(1900 – 0700 hours).
The
standard working hours will be from 0800 to 1800 hours. However, the following works may be
carried out during the evening or the night-time periods:
·
Blasting
and excavation works;
·
Dredging
by the larger Trailing Suction Hopper Dredger (TSHD);
·
Clearing
and crushing of the blasted rocks and their transportation off site during the
evening;
·
Installation
of gas pipeline;
·
Occasional
large concrete pours on the jetty head or the intake and outfalls being carried
out overnight, especially if daytime temperatures are high; and
·
Facility
construction works for the terminal facility including tank construction.
It should be noted that the onshore installation of the water main and
cable circuit will not be carried out during the restricted hours.
5.4.2
Operational Phase
Noise associated with the operational phase of the LNG
terminal would mainly arise from the plant at the terminal site. There will be no plant emitting noise in
the GRS and the dominant noise sources are mainly from the machines at the LNG
terminal on
· Heat exchangers, including
LNG submerged combustion vaporizers;
· Compressors and diesel
emergency generators;
· Various kind of pumps; and
· Special equipment such as
unloading arms and nitrogen generator.
The noise data for the equipment have made reference to manufacturers’
data and the results of field measurement conducted at overseas LNG
terminals. To minimise the noise impact to the environment, most
of the noise sources will be housed within individual enclosures or
claddings. As a conservative approach, it is assumed that all equipment will be
operated on a 24-hour basis. With
reference to the overseas LNG terminals, the equipment inventory are developed
by the Engineers and their respective sound power levels (SWLs) in one-one
octave bands provided by the Project Proponent are presented in Annex 5-D.
The suppliers of equipment should guarantee the specified SWL and the
equipment should be free of the characteristics of tonality, impulsiveness and
intermittency, by providing certificate of measurement and verify the SWL
during testing and commissioning in accordance with international standard
procedures. With such guarantee
included in LNG Procurement Contract, the noise emission from the equipment
should comply with the tender specification. If necessary, the suppliers should apply
attenuation measures to achieve the guaranteed noise levels determined during
the detailed design stage. The
proposed equipment is also confirmed to be available in the market.
5.5.1
Construction Phase
Construction Works Carried out During
The
methodology for the noise impact assessment is in accordance with the
procedures outlined in the GW-TM, which
is issued under the NCO and the EIAO-TM, and is summarized as follows:
·
Identifying
the likely type, sequence and duration of principal noisy construction
activities required for the implementation of the project;
·
Identifying
a list of construction plant likely to be required for each construction
activity;
·
Calculating
the maximum total SWL for each construction activity using the plant list and
SWL data given for each plant in the technical memorandum. When the PME is not listed in the TMs,
SWLs provided in the document prepared by the Noise Control Authority (http://www.epd.gov.hk/epd/english/application_for_licences/guidance/files/OtherSWLe.pdf
) and British Standard 5228, Noise and
Vibration Control on Construction and Open Sites - Part 1 (BS5228: Part 1:
1997) ([1])
are referred;
·
Identifying
representative NSRs as defined by the EIAO-TM
based on existing and committed land uses in the Study Area that may be
affected by the worksite;
·
As a
conservative approach, calculating the distance attenuation to an NSR from
nearest worksite; and
·
Predicting
construction noise levels at NSRs in the absence of any mitigation measures.
Using a conservative approach, each work activity has been assumed to
operate simultaneously and the time schedule of each activity has been provided
in Annex 5-B. Based on the construction programme,
cumulative noise impact throughout the construction phase has been assessed.
Due
to the large separation distance between the construction site and the NSR
(approximately 6 km), the noise will be reduced due to energy lost through
atmospheric absorption during transmission, therefore, a correction factor for
the atmospheric absorption has been calculated based on the ISO 9613([2])
procedure. Additionally, a facade
correction of +3 dB(A) is applied.
Predictions are made of the most conservative case construction noise
levels at the identified representative NSR.
Construction Works Carried out During Restricted Hours
Considering
the construction programme of the Project, night-time construction works will
need to be carried out. The site is
located outside designated areas as defined in DA-TM and the construction noise assessment for night-time works
has been carried out in accordance with the requirements of the GW-TM in the context of programming only.
5.5.2
Operational Phase
The
methodology for the noise impact assessment is in accordance with the
procedures outlined in the ISO 9613-1
and IND-TM, which is issued under the
NCO and the EIAO-TM. The methodology for the fixed plant noise assessment is presented below:
·
Identifying
types of equipment and the number of equipment;
·
Calculating
the maximum total SWL for each type of equipment;
·
Identifying
representative NSRs as defined by the EIAO-TM
based on existing and committed land uses in the Study Area that may be
affected by the worksite;
·
Calculating
the distance attenuation to the NSRs from noise sources; and
· Presenting the results in
terms of LAeq (30min) dB, as specified in the TM.
With
the considerable separation between the site and the noise sensitive receivers,
the atmospheric absorption during sound transmission is considered as one of
the major factors that will have a significant impact on the noise
prediction. Assessment results have
been predicted in a conservative approach without other attenuations due to
foliage of trees and shrubs, ground effects and buildings/claddings in which
the equipment are placed.
The
predicted noise levels at the NSR are compared with the criteria set out in Section 5.3.3. Mitigation measures will be proposed
should any exceedance be predicted.
5.6.1
Construction Phase
Construction
Works Carried out During
The
unmitigated construction noise levels at the NSRs (Staff Quarter of Shek Pik
Prison, Tai O Barrack and village house at Lung Kwu Sheung Tan) have been
predicted and are presented in Annex 5-E. The predicted construction noise levels
at the identified NSRs are in the range of 20 – 70 dB(A), which are below the
daytime construction noise criterion of 75 dB(A) throughout the construction
period and utilized the conservative set of assumptions in the analysis.
Percussive
Piling
Percussive
piling will be utilised for the construction of the trestle and LNG jetty. As the issuance of a CNP for percussive
piling by the Noise Control Authority
would depend on the submission of an application by the contractor, and
therefore on the contractor’s compliance with the percussive piling noise
limits set out within the PP-TM, the
assessment of this type of noise has not been included in this assessment. However, the contractors will follow the
procedure set out in the PP-TM, as
described in Section 5.2.1 to assess
the noise impact in the application of the CNP.
Construction
Works Carried out During Restricted Hours
The predicted noise levels for the installation of the water main and
electric cable, which will be conducted during the daytime period,
comply with the stipulated noise criterion of 75 dB(A). As mentioned in Section 5.4.1, some of the construction activities may be carried
out during restricted hours (1900 – 0700 hours), the predicted noise levels as
shown in the Annex 5-E are within the
ANLs stipulated in GW-TM throughout
the restricted hours. A CNP, as described in Section 5.2.1, is required for the
construction works being carried out during the evening and night-time period (1900 - 0700 hours) Monday through Saturday.
Based on the preliminary implementation programme,
some of the construction works may be carried out during restricted hours. Without evening and night-time works,
the project will be delayed by 16 - 19 months. Assessment on the construction works to
be carried out during restricted hours (1900 – 0700 hours) is included to
preliminarily appraise the feasibility in the context of programming. However, it should be noted that the
assessment provided here is for indicative purpose only and serves as a
reference for the future design and construction stage. Whether a CNP could be issued would be
subject to the discretion of the Authority taking into account the details and
information provided and the circumstance when the CNP application is
filed. The actual amount of
construction work and the resultant noise levels would comply with the
requirement of CNP.
Cumulative Impact
The construction of the karting track (as mentioned in Section 5.3.2) has been completed and is
operational in August 2006. In
addition, the village house (NSR N3) within the karting track site is used as
an office.
As mentioned in Section 3.7,
there will be no concurrent major projects to be constructed in the vicinity of
the NSRs, and therefore there will be no cumulative impact from the
construction of the LNG terminal and other major projects.
5.6.2
Operational Phase
The
most conservative case noise levels at the NSR N1 (Staff Quarter of Shek Pik
Prison) during the operational phase of the LNG terminal have been
predicted. The detailed calculation
of the predicted noise levels is presented in Annex 5-F. The
predicted noise levels is 29 dB(A) and is below the ANLs stipulated in the IND-TM during both daytime and
night-time period.
Cumulative
Impact
No
major projects are identified in the vicinity of the NSR N1, and therefore there
will be no cumulative impact at the NSR during the operational phase.
5.7.1
Construction Phase
The
predicted noise levels are low and below the daytime and night time criteria as
a result of the considerable separation distance between the NSR
and the Project.
Mitigation measures are therefore not required.
5.7.2
Operational Phase
The
predicted noise levels are below the daytime and night time criteria as a
result of the considerable separation distance between the NSR
and the Project.
Mitigation measures are therefore not required.
5.8
Environmental
monitoring and audit
5.8.1
Construction Phase
Given
the compliance with the stipulated noise criterion, noise monitoring is not
anticipated to be required during the construction phase.
5.8.2
Operational Phase
Given
the compliance with the stipulated noise criterion, noise monitoring is not
anticipated to be required during the operational phase.
The
identified noise sensitive receivers will not be affected by the construction
activities with the predicted construction noise levels at the NSRs in the
range of 20 – 70 dB(A), which is within the stipulated noise criterion of 75
dB(A). In view of the insignificant
construction noise impact, mitigation measures are not anticipated during the
construction phase.
Based
on the most conservative case, the noise levels generated from the equipment at the LNG
terminal have been predicted. Due
to the large separation distance between the NSR at Shek Pik and the noise
source, the predicted operational noise level is 29 dB(A), which is within
daytime and night-time noise criteria.
Therefore mitigation measures are not anticipated required during the
operational phase.
In view of the anticipated insignificant
noise impact in both construction and operational phases, noise monitoring is
not considered to be necessary.