5.0      Noise. 5-1

5.1            Introduction. 5-1

5.2            Environmental Legislation, Standards and Guidelines. 5-1

5.3            Description of the Environment 5-3

5.4            Identification of Noise Sensitive Receivers. 5-4

5.5            Construction Noise Impact Assessment 5-6

5.6            Operational Noise Impact Assessment 5-10

5.7            Environmental Monitoring and Audit 5-21

5.8            Conclusions. 5-22

 

TABLES

Table 5.1         Noise Standards for Daytime Construction Activities (Non-restricted Hours)

Table 5.2         Helicopter Noise Standards for Planning Purposes

Table 5.3         Representative Noise Sensitive Receivers

Table 5.4         Powered Mechanical Equipment for Construction of the Proposed Helipad

Table 5.5         Predicted Construction Noise Levels

Table 5.6         Predicted Cumulative Construction Noise Level

Table 5.7         Emergency Helicopter Landing at PYNEH (2015 ¡V 2019)

Table 5.8         Noise Data of Airbus H175 ¡V Lateral Movements

Table 5.9         Noise Measurement Results of Airbus H175 ¡V Non-lateral Movements

Table 5.10       Minimum Buffer Distance Required for Airbus H175

Table 5.11       Predicted Unmitigated Helicopter Noise Levels

Table 5.12       Summary of Proposed Noise Barrier and Noise Reducers

Table 5.13       Predicted Mitigated Helicopter Noise Levels

Table 5.14       Statistics of Helicopter Noise Complaint of TMH and PYNEH

 

 

FIGURES

Figure 5.1       Representative Noise Sensitive Receivers

Figure 5.2       Helicopter Flight Path

Figure 5.3       Schematic for Typical Helicopter Operation

Figure 5.4a     Noise Buffer Zone for Flight Path

Figure 5.4b     Noise Buffer Zone for FATO of Helipad

Figure 5.5       Proposed Noise Barrier and Noise Reducers

Figure 5.6a     Helicopter Noise Contour (Non-lateral Movement) at +118.2 mPD

Figure 5.6b     Helicopter Noise Contour (Non-lateral Movement) at +98.2 mPD

Figure 5.6c     Helicopter Noise Contour (Non-lateral Movement) at +38.2 mPD

Figure 5.6d     Helicopter Noise Contour (Non-lateral Movement) at +5.7 mPD

Figure 5.7a     Helicopter Noise Contour (Lateral Movement) at +118.2 mPD

Figure 5.7b     Helicopter Noise Contour (Lateral Movement) at +98.2 mPD

Figure 5.7c     Helicopter Noise Contour (Lateral Movement) at +38.2 mPD

Figure 5.7d     Helicopter Noise Contour (Lateral Movement) at +5.7 mPD

 

 

APPENDICES

Appendix 5A   Review of Overseas / International Practices on Noise Assessment for Emergency Helicopter Operations during Evening and Night-time Periods

Appendix 5B   Details of Representative Noise Sensitive Receivers

Appendix 5C   Calculation of Construction Noise Levels

Appendix 5D   Airbus H175 Noise Certificate

Appendix 5E   Helicopter Noise Survey Report

Appendix 5F   Calculation of Helicopter Noise Levels

Appendix 5G   Illustration of Noise Screening

Appendix 5H   Advice from Government Departments

5.0              Noise

 

5.1                Introduction

 

5.1.1.1       This section presents the noise impact assessment of the Project, identifying the potential noise issues during the construction and operational phases, evaluating the potential noise impacts on the identified noise sensitive receivers (NSRs) in the vicinity of the Project and recommending mitigation measures as necessary.  

5.1.1.2       During the construction phase, Powered Mechanical Equipment (PME) to be used for the construction works will be the primary noise source.  The major noise generating activities will include the Construction of the helipad and associated structures including covered safety walkway, staircase, noise barrier, etc.

5.1.1.3       During the operational phase, the proposed helipad will only be used for medical emergencies, such as CASEVACs and Search and Rescue (SAR) by the Government Flying Service (GFS).  The helipad will not be used for commercial operations, transportation of guests, training flights or other non-emergency uses, except trial flights.  The major noise source due to the Project in the operational phase will be from helicopter maneuvering as indicated below:

¡P         Lateral movements of the helicopter including approach towards and departure from the proposed helipad along its flight path; and

¡P         Non-lateral movements of helicopter including landing on and hovering directly over the proposed helipad.

5.1.1.4       The noise impact assessment for the Project has been conducted in accordance with the Annexes 5 and 13 of the Technical Memorandum on Environmental Impact Assessment Process (TM-EIAO).  

5.2                Environmental Legislation, Standards and Guidelines

 

5.2.1           Background

5.2.1.1       The Noise Control Ordinance (NCO) (Cap. 400) provides the statutory framework for noise control.  However, the NCO does not apply to noise caused by aircraft, while this type of noise is controlled under the Civil Aviation (Aircraft Noise) Ordinance (Cap. 312).  The Environmental Impact Assessment Ordinance (EIAO) (Cap. 499) provides the framework for assessment of the noise impact for designated projects. 

5.2.1.2       Reference to the EIAO and the relevant technical memoranda has been made for the assessment of noise impacts.  Annexes 5 and 13 of the TM-EIAO set out the criteria and guidelines for evaluating noise impacts.  Assessment procedures and standards are set out in the following technical memoranda and Guidance Note:

¡P         Technical Memorandum on Environmental Impact Assessment Process (TM-EIAO);

¡P         Technical Memorandum on Noise from Construction Work other than Percussive Piling (TM-GW);

¡P         Technical Memorandum for the Assessment of Noise from Places other than Domestic Premises, Public Places or Construction Sites (IND-TM); and

¡P         EIAO Guidance Note ¡V Preparation of Construction Noise Impact Assessment under the Environmental Impact Assessment Ordinance (GN9/2010).

 

 

5.2.2           Construction Phase

Construction Noise during Non-restricted Hours

5.2.2.1       Daytime construction noise, excluding percussive piling, between the hours 0700 ¡V 1900 on weekdays, that is non-restricted hours, should be assessed in accordance with TM-EIAO.  Annex 5 of the TM-EIAO sets out the noise standards for daytime construction activities, which are Leq(30 min) 75dB(A) for domestic premises and hotels, and Leq(30 min) 70dB(A) during normal hours for education institutions including kindergartens (65dB(A) during examination periods), nurseries and all other places where unaided voice communication is required.  Noise standards for daytime construction activities are summarised in Table 5.1.

Table 5.1    Noise Standards for Daytime Construction Activities (Non-restricted Hours)

Uses

Construction Noise,

Leq (30 mins), dB(A)

All domestic premises including temporary housing accommodation

75

Hotels and hostels

75

Educational institutions including kindergartens, nurseries and all others where unaided voice communication is required

70

65   (During examinations)

Note: 

1.       The above standards apply to uses which rely on opened window for ventilation.

2.       The above standards shall be viewed as the maximum permissible noise levels assessed at 1m from the external facade.

5.2.3           Operational Phase

Helicopter Noise (Daytime Period)

5.2.3.1       The TM-EIAO provides standards for helicopter noise levels for the daytime period between the hours 0700 - 1900 for planning purposes.  The relevant criteria are shown in Table 5.2.

Table 5.2    Helicopter Noise Standards for Planning Purposes

Common Uses

Helicopter Noise, Lmax, dB(A)

All domestic premises including temporary housing accommodation

85

Hotel and hostels

85

Offices

90

Educational institutions including kindergartens, nurseries and all others where unaided voice communication is required

85

Places of public worship and courts of law

85

Hospitals, clinics, convalescences and homes for the aged, diagnostic rooms, wards

85

Note: 

1.       The above standards apply to uses which rely on opened window for ventilation.

2.       The above standards should be viewed as the maximum permissible noise levels assessed at 1m from the external facade.

 

Helicopter Noise (Evening and Night-time Period)

5.2.3.2       In accordance with the TM-EIAO, there are no specific noise standards for helicopter noise during the evening (1900-2300) and night-time (2300-0700) periods between the hours of 1900 and 0700 on the next day. 

5.2.3.3       Criteria for evaluating such helicopter noise impacts shall be established on a case-by-case basis so as to assess whether the proposed methodology are consistent with the methodologies adopted for Hong Kong projects having similar issues or with methodologies accepted by recognised national / international organisations.

5.2.3.4       Therefore, considering the nature of this Project, reference has been made to the approved EIA report for ¡§A Rooftop Helipad at the Proposed New Block of Queen Mary Hospital¡¨ (Register No. AEIAR-208/2017) (QMH Helipad EIA).  The QMH Helipad EIA, which was approved in March 2017, is considered as the latest and the most relevant EIA in similar nature for reference.  The proposed rooftop helipad at Queen Mary Hospital is considered to be comparable to this Project as both are rooftop helipads on a trauma hospital proposed for emergency helicopter operations only. 

5.2.3.5       A review of the local and overseas/ international practices was conducted and presented in the QMH Helipad EIA to investigate suitable assessment approaches for the noise impact arising from emergency helicopter operations during the evening and night-time periods.  Practices in overseas regions where the urban settings are similar to Hong Kong where made reference to, including the United States of America (California), Australia (Victoria), Japan and Singapore.  According to the findings in the QMH Helipad EIA, there is no statutory noise criterion for emergency services, including air ambulance, SAR, supporting law enforcement agencies, firefighting etc., during the evening and night-time periods with such emergency services being generally exempted from the flight restrictions.  Noise criteria were not proposed for emergency helicopter operation during evening and night-time periods based on the similar situation to these reviewed cities/countries.  These review findings have been checked and considered valid as summarized in Appendix 5A.

5.2.3.6       The use of this proposed helipad during evening and night-time period has similar situations to those reviewed cities/countries, and the QMH Helipad.  Therefore, in view of emergency nature and without scheduled flight, noise criteria were not proposed for emergency helicopter operation during evening and night-time period for the Project. 

5.3                Description of the Environment

 

5.3.1.1       As described in Section 2.2, there are three sites earmarked for hospital development in the former south apron area of Kai Tak Development Area (KTDA), which are Site 3C1(A), Site 3C1(B) and Site 3C1(C) (hereinafter described as ¡§Sites A, B and C¡¨ respectively).  Site A and Site B have been allocated for development of the NAH, while Site C is occupied by the Hong Kong Children¡¦s Hospital (HKCH), which commenced operation in 2018.  Site A abuts Kwun Tong Bypass, Cheung Yip Street and Shing Cheong Road, while Site B abuts the planned Roads L10, L18 and D4.  The construction works for the foundations for the proposed NAH in both Site A and Site B commenced in 2018.  The Acute Block of NAH will be located at the south-east part of Site A, and the Project site for the helipad is proposed to be located on the roof of the Acute Block.  The location of the Project site is shown in Figure 1.1.  The land use of the Project Site and its environs are shown in Figure 2.1.

5.3.1.2       Adjacent to the eastern corner of Site A at Cheung Yip Street, there is the existing Kai Tak Fire Station.  Two sites for Transport Department vehicle examination centres are located beyond the Kwun Tong Bypass, which are to the north of Site A.

5.3.1.3       To the south-east of Site A, and opposite to the Acute Block, a planned residential zone is located with a separation distance of approximately 50m.  The planned residential zone is zoned ¡§Residential (Group B)¡¨ (¡§R(B)2¡¨) according to the approved Kai Tak OZP No. S/K22/6. This R(B)2 zone consists of two adjacent sites, one located next to waterfront area, which has a building height restriction of +80mPD and is currently the Public Works Central Laboratory Building, while the other one at Lam Chak Street has a building height restriction of +100mPD and is currently the Kowloon Bay Parking site.

5.3.1.4       Further to the east of Site A, two areas zoned ¡§Commercial (2)¡¨ are found along both sides of Kai Hing Road. The existing Pacific Trade Centre bounded by Lam Chak Street and Cheung Yip Street is located at about 50m from Site A while the existing Kowloon Godown, Kerry Dangerous Goods Warehouse (Kowloon Bay) and open storage are located at about 140m from Site A.  Planning status of the Kerry Dangerous Goods Warehouse (Kowloon Bay) site is detailed in Section 5.4.1.5.

5.3.1.5       In the ex-Kai Tak Runway in KTDA, there are planned residential zones, currently zoned ¡§Residential (Group B)¡¨ (¡§R(B)4), ¡§R(B)5¡¨ and ¡§R(B)7¡¨) and with building height restrictions ranging from +95mPD to +120mPD, are found.  These zones are located along Shing Fung Road (i.e. Road D3A) across the Kai Tak Approach Channel. The nearest residential zone is about 450m to the southwest of the Project site.

5.3.1.6       Site visits were conducted in August 2019.  Based on the site observation, the existing noise environment in the vicinity of the proposed helipad was dominated by the construction activities in Site A and Site B of NAH and traffic noise from the nearby Kwun Tong Bypass.

5.4                Identification of Noise Sensitive Receivers

 

5.4.1.1       Noise Sensitive Receivers (NSRs) have been identified.  Relevant Outline Zoning Plans (OZP) (i.e. Approved Kai Tak OZP No. S/K22/6, Draft Ngau Tau Kok and Kowloon Bay OZP No. S/K13/29 and Approved Kwun Tong (South) OZP No. S/K14S/22), development applications approved by the Town Planning Board (TPB), survey maps, topographic maps and aerial photos etc., have been referenced in identifying the existing and planned NSRs.  Site surveys have been carried out to confirm the status of existing representative NSRs.  Noise sensitive uses relying on opened windows for ventilation have been selected.

5.4.1.2       In accordance with the EIA Study Brief No. ESB-311/2019, the assessment area for noise impact assessment shall generally include areas within 300m from the boundary of the Project site.  The assessment area shall be expanded to include NSRs at a distance over 300m from the Project, associated works and along the flight paths of the helicopter where appropriate, if those NSRs could be affected by the construction and operation of the Project.  NSRs which are potentially affected by the helicopter operations, but located over 300m from the Project, are also included in the assessment. 

5.4.1.3       It is noted that the Acute Block and other four blocks of the NAH will be provided with central air-conditioning system and well-gasketted windows and do not rely on opened window for ventilation, which are similar to the existing HKCH.  Therefore, the NAH and HKCH would not be considered in the noise impact assessment.  It is also confirmed that no noise sensitive uses which rely on opened windows for ventilation is inside the Kai Tak Fire Station.  Therefore, the Kai Tak Fire Station would not be considered in the noise impact assessment.  Relevant advice form FSD is shown in Appendix 5H-4.

5.4.1.4       In accordance with TPB Paper No. 10236, the earliest design year for those proposed residential developments on Kai Tak Development (KTD) Sites 3E1, 3E2, 4E1, 4A1, 4B1, 4B2, 4B3 and 4B4 is 2026, which is later than year 2024, the completion year of the construction works of this Project as advised by the Project team.  It is noted that some of these sites in the ex-Kai Tak Runway have been sold according to land sale records, such as Sites 4A1, 4B1, 4B2, 4B3, 4B4, etc., however, they are all located over 300m from the Project.  Hence, it is anticipated that these planned residential sites will not be affected by any potential construction noise during the entire construction period (i.e. Q4 2023 to Q4 2024) of the Project. 

5.4.1.5       According to the Section 16 planning application Case No. A/K22/13-1 approved under the Town Planning Ordinance, permission for residential developments proposed on 7 Kai Hing Road (NKIL 5813) has been granted and valid until 30 March 2020.  Therefore, the permission is considered as expired.  Nonetheless, according to the Section 16 planning application Case No. A/K22/27, a proposed redevelopment on the site to a commercial building has been applied for, and is under review at the time of preparation of this EIA report.  Although NKIL 5813 is a commercial zone currently occupied by the Kerry Dangerous Goods Warehouse (Kowloon Bay), and the information or population intake programme for the proposed residential development is not available at the time of preparing this EIA report, it would be considered as a representative planned NSR for conservative assessment in both construction and operational phases. 

5.4.1.6       No existing NSR would be affected within the 300m study area.  However, the nearest existing NSR, namely the Construction Industry Council Kowloon Bay Training Centre (CIC Kowloon Bay), which would likely be affected, is located approximately 461m from the Project site and has been included in the operational helicopter noise impact assessment.  

5.4.1.7       Descriptions and locations of the identified representative NSRs are summarised in Table 5.3 and indicated in Figure 5.1.  The height information assumed for the NSRs and photos of the existing NSR are shown in Appendix 5B.

Table 5.3    Representative Noise Sensitive Receivers

NSR ID

Description

Zoning

Noise Sensitive Use

Distance from Project (m)

CNIA(1)

HNIA(2)

Existing NSR

E01

Construction Industry Council Kowloon Bay Training Centre (CIC Kowloon Bay)

Government, Institution or Community

Education Institution

465

-

Yes

Planned NSRs

P01a

Kai Tak Development Site 3E1 (KTD Site 3E1)

Residential (Group B)

Domestic Premises

154

-

Yes

P01b

155

-

Yes

P01c

164

-

Yes

P02a

Kai Tak Development Site 3E2 (KTD Site 3E2)

Residential (Group B)

Domestic Premises

163

-

Yes

P02b

214

-

Yes

P03

Proposed Residential Development at Kerry Dangerous Goods Warehouse (Kowloon Bay) (NKIL 5813)

Commercial

Domestic Premises

249

Yes

Yes

P04

Kai Tak Development Site 4E1 (KTD Site 4E1)

Residential (Group B)

Domestic Premises

633

-

Yes

P05

Kai Tak Development Site 4A1 (KTD Site 4A1)

Residential (Group B)

Domestic Premises

442

-

Yes

P06

Kai Tak Development Site 4B1 (KTD Site 4B1)

Residential (Group B)

Domestic Premises

402

-

Yes

P07

Kai Tak Development Site 4B2 (KTD Site 4B2)

Residential (Group B)

Domestic Premises

401

-

Yes

P08

Kai Tak Development Site 4B3 (KTD Site 4B3)

Residential (Group B)

Domestic Premises

420

-

Yes

P09

Kai Tak Development Site 4B4 (KTD Site 4B4)

Residential (Group B)

Domestic Premises

497

-

Yes

Note: 

(1). CNIA ¡V Construction Noise Impact Assessment

(2). HNIA ¡V Helicopter Noise Impact Assessment

5.5                Construction Noise Impact Assessment

5.5.1           Identification of Noise Impact

5.5.1.1       As mentioned in Section 2, the Project will be constructed after the completion of superstructure work for the Acute Block of the New Acute Hospital (NAH).  The proposed helipad will be built on the rooftop of the newly constructed Acute Block of the NAH and, therefore, demolition works, site formation and superstructure works are not required for the Project.  The potential construction noise source will be from the PME to be used during construction activities for the steel framework, helipad structure, safety walkway, access ramp and noise barrier. 

5.5.2           Assessment Methodology

5.5.2.1       The assessment of noise impacts from the construction (excluding percussive piling) of the Project has been based on the methodology given in Annex 13 of the TM-EIAO.  The typical approach is summarised as follows:

¡P                    Formulate construction programme and work sequences;

¡P                    Identify representative NSR that may be affected by the construction of the Project;

¡P                    Establish the construction plant inventory;

¡P                    Assign Sound Power Level (SWL) for each piece of PME based on the TM-GW and the list of Sound power level of other commonly used PME;

¡P                    Calculate the correction factors based on the distance between the NSR and the notional noise source positions at different works areas;

¡P                    Apply noise corrections in the calculations for distance, operation time, screening and façade correction, if any;

¡P                    Predict the construction noise levels at NSR and compare against the noise standards (Table 5.1); and

¡P                    Determine mitigation measures, as necessary, and assess any residual impacts.

5.5.2.2       The predicted construction noise level (CNL) at the NSR is calculated based on the equation defined below:

                              CNL = SWLTotal +CD +Cs +CT +CF

Where,

SWLTotal - Total sound power level, dB(A);

CD - Distance correction, dB(A);

CB - Screening correction, dB(A);

CT - Percentage on time correction, dB(A)

CF - Façade correction, dB(A).

5.5.3           Noise Emission Inventory

5.5.3.1       The construction works of the helipad and the associated structures will be constructed after the completion of superstructure work for the Acute Block of NAH.  The construction works of the helipad and the associated structures will be conducted in one phase for worst-case assessment.  The construction programme, construction plant inventory and percentage on time of each piece of PME have been provided and confirmed reasonable, feasible and practicable by the Engineer/ HA based on the best available information at the moment, including the proposed construction method as presented in Section 2.5.  The inventory will be subject to change by the Contractor in future.  The construction schedule provided by the Engineer has been prepared based upon an assumption that all works will be undertaken during non-restricted hours only.  As refer to the implementation programme of the Project in Section 2.6, the construction will be tentatively commenced in Q4 2023, and completed in Q4 2024.  The PME to be used for the helipad construction and their SWLs are listed in Table 5.4 and Appendix 5C.

Table 5.4    Powered Mechanical Equipment for Construction of the Proposed Helipad

PME Adopted

ID code in TM-GW

SWL, dB(A)

No. of PME

Air Compressor, air flow < 10m3/min

CNP 001

100

1

Crane, tower (electric)

CNP 049

95

1

Breaker, hand-held, mass > 35kg

CNP 026

114

1

Welding Set

Note (1)

78

2

Note: 

(1). SWL of Welding Plant was referenced from the approved EIA Report of West Kowloon Cultural District (Register No. AEIAR-178/2013).

5.5.4           Prediction and Evaluation of Construction Noise Impact

5.5.4.1       The construction noise impact assessment has been conducted based on the construction plant inventory for the helipad construction. 

5.5.4.2       All pieces of the PME for general construction works have been assumed to be placed at a single notional source at a position mid-way between the approximate geographical centre of the construction site and the boundary nearest to the NSR. This position is referred to as the notional source position according to the TM-GW. However, considering the size of helipad, with a diameter of 30m, is relatively small when compared to general construction sites, the notional source position will be assumed as the point of the helipad nearest to the NSR for conservative assessment.  A 3dB(A) has been added to the predicted noise levels as a façade correction.

5.5.4.3       The maximum predicted noise level at the NSR during construction phase is summarized in Table 5.5.  Detailed calculation is given in Appendix 5C.

5.5.4.4       According to the assessment result in Table 5.5, the predicted maximum construction noise levels at the NSR would not exceed the noise criterion of 75dB(A).

Table 5.5    Predicted Construction Noise Level

NSR ID

NSR

CNL (Leq(30 mins)), dB(A)

Assessment Criterion, dB(A)

P03

Proposed Residential Development at Kerry Dangerous Goods Warehouse (Kowloon Bay) (NKIL 5813)

61

75

 

5.5.4.5       In addition, the structural works for the proposed helipad would take approximately one year only.

5.5.4.6       Considering the above, no adverse construction noise impacts are anticipated.

5.5.5           Cumulative Impacts with Concurrent Project

Concurrent Projects

5.5.5.1       Key concurrent projects in the vicinity of the proposed helipad are identified in Section 2.7.  Those projects that would have potential construction works undertaken concurrently with the helipad construction (i.e. 2023 to 2024) are detailed below.  The construction activities of the projects taking place concurrently within 300m of a given NSR would be considered to contribute to the cumulative impacts at those NSRs.

New Acute Hospital at Kai Tak Development by Hospital Authority

5.5.5.2       The proposed helipad will be constructed after the completion of superstructure for the NAH.  However, there will be concurrent construction of the proposed helipad and the finishing works for both Site A and Site B of NAH between 2023 and 2024.  The type, operation time and quantities of the PME likely to be used for the finishing works of the NAH and their SWLs are presented in Appendix 5C.  The construction programme and construction plant inventory adopted for the assessment is confirmed and provided by the Project Engineer who is responsible for the design of construction works of NAH.

Central Kowloon Route - Slip Road S5 by HyD

5.5.5.3       The construction of the Slip Road S5 project will tentatively commence in 2023 and be completed in 2024.  The 300m boundary of the project does not cover the NSR P03.  Therefore, the potential cumulative noise impact arising from the construction of Slip Road S5 has not been included in this noise assessment.

Kai Tak Development - Trunk Road T2 and Infrastructure at South Apron by CEDD

5.5.5.4       According to the approved EIA report for the Trunk Road T2 (Register No. AEIAR-174/2013), the Trunk Road T2 is planned to be a dual 2-lane highway of about 3.0 km connecting the Central Kowloon Route (CKR) and Tseung Kwan O ¡V Lam Tin Tunnel (TKO-LTT).  Construction of the Trunk Road T2 will commence in 2020, and it is targeted to be completed in 2026.  Hence, there will be concurrent construction with the proposed helipad.  In addition, it is noted that NSR P03 is located within the 300m assessment area of the Trunk Road T2 project.  Therefore, Trunk Road T2 has been identified as a concurrent project which may contribute potential cumulative impacts at NSR P03.  With reference to the approved EIA report for Trunk Road T2 (Register No. AEIAR-174/2013), the maximum predicted mitigated construction noise level at NSR P03, referred to as NSR KER1 in AEIAR-174/2013, is 75dB(A).

Kai Tak Development ¡V Remaining infrastructure works for Developments at the Former Runway and South Apron, Road L10 & 18 by CEDD

5.5.5.5       The construction of the Road L10 & 18 project was commenced in 2019 and will be tentatively completed in 2026.  However, this project is located more than 300 from the NSR P03.  Therefore, the potential cumulative noise impact arising from the construction of Road L10 & 18 has not been included in this noise assessment.

Cumulative Impacts

5.5.5.6       The cumulative noise impacts at the NSR have been assessed and summarised in Table 5.6. Detailed calculation is given in Appendix 5C.

Table 5.6    Predicted Cumulative Construction Noise Level

Concurrent

Projects

CNL (Leq(30 mins)), dB(A)

Cumulative

CNL (Leq(30 mins)), dB(A)

Assessment

Criterion, dB(A)

The Project

61

75

75

Site A of NAH

58

Site B of NAH

46

Trunk Road T2

75

5.5.5.7       The predicted cumulative construction noise level at the representative NSR, the proposed Residential Development at Kerry Dangerous Goods Warehouse (Kowloon Bay), does not exceed the noise criterion of 75dB(A).  Hence, adverse cumulative construction noise impacts are not anticipated.

5.5.6           Mitigation of Construction Noise Impact

5.5.6.1       The assessment results show that there would be no adverse noise impact at the identified NSR and no mitigation measures would be required.  However, good site practices and use of quieter construction plant are still recommended to minimise the noise impact during the construction of the proposed helipad.  The following site practices are recommended:

¡P                    Quiet powered mechanical equipment (QPME) shall be used, and PME shall also be serviced regularly during the construction programme;

¡P                    Only well maintained plants shall be used in the construction of the Project; and

¡P                    Machines and plant that may be in intermittent use should be shut down between works periods or throttled down to a minimum between work periods.

5.5.6.2       Besides, the ¡§Recommended Pollution Control Clauses for Construction Contracts¡¨ published by the EPD should be adopted in the Contract Specification for the Contractors to follow and implement relevant measures and good site practices in minimising noise impact.

5.5.7           Residual Impacts

5.5.7.1       Cumulative construction noise impacts on the representative NSR are assessed and comply with the daytime construction noise standard.  No adverse residual impact is anticipated during the construction phase of the Project.

5.6                Operational Noise Impact Assessment

5.6.1           Identification of Potential Noise Impacts

Background

5.6.1.1       During the operational phase, the key noise issue would be from the helicopter operations associated with the proposed Helipad.  There are no other noise sources associated with the Project in the operational phase.  Other potential noise sources proposed for the NAH, such as outdoor building services equipment, shall be assessed under a separate environmental study and designed to fulfill the relevant environmental requirements.

Helicopter Operational Mode

5.6.1.2       Noise will be generated by helicopters during manoeuvring over the helipad within the Final Approach and Take-Off (FATO) area, lateral (approaching / departure) flight movements and flyover.  The different operational modes that may generate noise are summarised as follows:

Non-lateral Movements

¡P                    Hovering: Helicopter turns on the spot over the helipad to achieve the desirable orientation for touchdown / lift-off;

¡P                    Touchdown: Helicopter descends on the helipad surface;

¡P                    Idling: Helicopter remains on the helipad surface with its rotary blades kept running; and

¡P                    Lift-off: Helicopter ascends vertically from the helipad surface to achieve a hover before departure.

Lateral Movements

¡P                    Approach: Helicopter approaches the helipad while it is descending at an angle to the helipad surface;

¡P                    Take-off: Helicopter leaves the helipad while it is climbing up at an angle to the helipad surface; and

¡P                    Flyover: Helicopter cruises before approach or after take-off.

Flight Sectors

5.6.1.3       The selection of flight sectors for the helicopter flights to and from the proposed helipad has been based on the following considerations.  The flight sectors in the north-west and south-east, and south have been recommended by the GFS for the proposed helipad.  The extent of the flight sectors and the locations of the representative NSRs are presented in Figure 5.2.  The GFS has emphasised that the proposed flight sectors are the best compromise with all factors and have been kept to a minimum in size so as to minimise the potential for noise impact on the surroundings.  The flight paths to and from the proposed helipad have been carefully defined for helicopters to fly over the Kai Tak Approach Channel or Kwun Tong Typhoon Shelter and away from densely populated areas such as the ex-Kai Tak Runway to the south-west, Kowloon Bay to the north and Kwun Tong to the east.  Meanwhile, a minimum horizontal buffer distance of 116m from NSRs could be maintained by the chosen flight paths as illustrated in Figure 5.4a (Refer to Section 5.6.4.1).  Relevant advice from GFS is given in Appendix 5H-2.  As advised by the GFS, the chosen flight paths during the operation of the helipad may be altered slightly subject to the actual weather conditions and the obstacles clearance to the surroundings, such as movement of birds or unexpected localised turbulence. Furthermore, subject to flight condition, helicopter operations are expected to be in one-way-direction within the selected flight sectors, that is, the arrival flight and departure flight shall be from east to west or east to south-west and vice versa.  Using the same flight path for approaching and departure of each operation is not preferred to minimise the overall exposure from helicopter noise at the NSRs.

Flight Profile

5.6.1.4       Based on details from the GFS, in preparing for departure, the helicopter will descend with a gentle slope until it reaches a flight height of 300ft above the helipad.  Within 300ft above the helipad, the flight path shall be projected at a gradient of 8% (about 4.6 degrees) for both approaching and departure.  The schematic for typical helicopter operation is illustrated in Figure 5.3.  Relevant advice from GFS is given in Appendix 5H-3.  The summary of the typical flight profiles is as follows:

1.    Cruise / Flyover: Typical flight height of 1500ft above mean sea level with flight speed of 140kts, descending 500ft/min with flight speed of 100kts until 300ft above the helipad;

2.    Approach: From 300ft above the helipad, flight speed would reduce from 60kts to 0kts with an approach angle of 4.6 degrees within 60 seconds;

3.    Hovering (Approach): The desirable orientation for touchdown would be achieved within 5 seconds at around 2.5m above the helipad;

4.    Touchdown: Descends on to the helipad within 3 seconds;

5.    Idling: 5 minutes for casualty handover under normal circumstances;

6.    Lift-off: Ascends from helipad to achieve a hover before departure within 3 seconds;

7.    Hovering (Departure): Achieve desirable orientation for take-off within 5 seconds, at around 2.5m above helipad;

8.    Take-off: Flight speed increases from 0kts to 60kts with a departure angle of 4.6 degrees within 60 seconds up to 300ft above the helipad; and

9.    Cruise / Flyover: Ascends at 500ft/min with a flight speed of 100kts until achieve a typical flight height of 1500ft above mean sea level, at typical flight height, the flight speed increases to 140kts.

Flight Frequency

5.6.1.5       As mentioned in Section 5.1.1.3, the proposed helipad at the NAH will be solely used for emergency use and not for scheduled helicopter operations except trial flights.  Table 5.7 presents the record of the GFS¡¦s emergency helicopter operations at the PYNEH, the current most utilised hospital helipad, between 2015 and 2019.  Relevant advice from GFS is given in Appendix 5H-3.

Table 5.7      Emergency Helicopter Landing at PYNEH (2015 ¡V 2019)

PYNEH Helipad

2015

2016

2017

2018

2019

D

E

N

D

E

N

D

E

N

D

E

N

D

E

N

No. of flight

 

152

17

32

153

31

31

218

32

45

164

35

42

175

33

42

Average no. of day(s) per flight

2.4

21.5

11.4

2.4

11.8

11.8

1.7

11.4

8.1

2.2

10.4

8.7

2.1

11.1

8.7

Total in the year:

201

215

295

241

250

Source:

1.     Data are advised by Government Flying Service

Note:

1.     D ¡V Daytime (07:00 ¡V 19:00); E ¡V Evening Time (19:00 ¡V 23:00); N ¡V Night-time (23:00 ¡V 07:00).

2.     All emergency flights including all type CASEVACs and SAR are presented as reference for the assessment.

 

5.6.1.6       According to Table 5.7, the highest annual emergency helicopter landing at PYNEH was found in 2017.  The flight records reflected that the average number of daily emergency helicopter landing was less than one, with emergency helicopter landings in the daytime period being about once every one to two days on average.  Also, the evening and night-time emergency helicopter landings at the PYNEH were one flight about more than every ten days and eight days respectively on average.

5.6.1.7       The proposed helipad at the NAH, together with the planned helipad at QMH upon its completion, shall share the existing number of helicopter landings and, thus, the flight frequency at the PYNEH would be reduced in future.  Also, since the existing flight frequency at PYNEH shall be shared by the proposed helipad at NAH, it is expected that the flight frequency at NAH would not be higher than the existing flight frequency at the PYNEH conservatively.

5.6.1.8       In preparation for the provision of 24-hour emergency services, trial flights will be conducted by the GFS at least two months (or earlier if the helipad facilities are available) prior to the commissioning of the proposed helipad for the NAH operations.  Around 2- 3 trial flights will be arranged per week during the daytime and evening time.  The purpose of the trial flights is to confirm the flight perimeters of the flight sectors and for the GFS¡¦s aircrew to familiarise themselves with the operational procedures and operating environment.  Before the helipad commissioning, the GFS will conduct trial flights mainly during the daytime to begin with, followed by some evening trials between 19:00 to 23:00.  It is noted that the GFS will minimise the evening trials and will not conduct trial flights during the night-time between 23:00 to 07:00 of the next day to reduce the possible noise impacts to the surroundings.  When the helipad is fully operational, trial flights will only be arranged on a need basis, that is for pilots away from office during the familiarisation phase, for new GFS pilots or if some major new developments are implemented in the vicinity of the proposed helipad that may cause concerns to flight safety.

5.6.2           Assessment Methodology

5.6.2.1       According to Table 1A, Annex 5 of the TM-EIAO, helicopter noise impacts at an NSR shall be assessed in terms of A-weighted maximum sound pressure level Lmax.  The helicopter noise level (Lmax) at an NSR can be calculated using the following formula:

                              Lmax = Lmax(ref) + CD +CB +CF

Where,

Lmax ¡V Helicopter noise level at 1m from the external façade of NSR, dB(A);

Lmax (ref) ¡V Sound Pressure Level at reference distance, dB(A);

CD ¡V Distance correction, dB(A);

CB ¡V Barrier correction, dB(A);

CF ¡V Façade correction, dB(A).

 

5.6.2.2         Since all the identified NSRs are located at some distance, over 150m, from the FATO of the proposed helipad and the helicopter flight paths, the helicopter can be considered as a ¡¥point¡¦ source for noise assessment.  Therefore, the sound pressure level at NSRs has been evaluated based on standard acoustic principles of a ¡¥point¡¦ source, that is,the sound pressure received at NSRs will be inversely proportional to the square of the distance between the noise source and the NSR.  The distance correction CD can be calculated using the following formula:

                              CD = ¡V20log10(R / R(ref))

Where,

R ¡V Shortest distance from a noise source to NSR, m;

R(ref) ¡V Reference distance from a noise source to a measurement point, m.

 

5.6.2.3       A barrier correction of ¡V5dB(A) has been applied where the representative NSRs are screened with no direct line of sight by a substantial barrier.  A façade correction of +3dB(A) has, also, been assumed at the representative NSRs in order to account for the reflection effect due to building façades. 

5.6.2.4       Wind speed and direction can influence sound propagation especially over long distances.  However, the wind speed and wind direction are unpredictable as they are not steady and can vary from time to time.  As detailed in Sections 5.6.1.4 and 5.6.1.6, the emergency helicopter operations are expected to be less than once a day on average and the duration of different operational modes range from 2-3 seconds to 5 minutes.  According to the QMH Helipad EIA, the co-existence of wind, which will enhance the sound perceived, that is, wind bending down after blowing above a ridge line, and the GFS¡¦s helicopter operations should be rare.  The ¡§Transportation Noise Reference Book¡¨ (P. M. Nelson, 1987, England: Butterworths) mentions that the prediction of aircraft noise traditionally and consciously avoids the wind effect by stating noise levels for a ¡§still air¡¨ situation.  Reference to overseas practices, including Japan and Australia, have been made in the QMH Helipad EIA and states that helicopter noise standards and assessments do not take account of the effects of wind.  In addition, according to the practices detailed in the Technical Memorandum for the Assessment of Noise from Places other than Domestic Premises, Public Places or Construction Sites (IND-TM) issued under the NCO, noise measurements should not be carried out at a time and location which is affected by wind as it would generate noise/affect the measurement results.  Therefore, it is considered inappropriate to include the wind effect in the helicopter noise impact assessment for the reasonable worst case scenarios and the adoption of the correction for wind effect is not considered in the assessment.

5.6.3           Helicopter Noise Levels

5.6.3.1       As mentioned in Section 2.2.3.1, the three Super Puma AS332 L2 helicopters and four Dauphin EC155 B1 helicopters previously utilised for emergency evacuations have been replaced by seven medium-sized single-model helicopters Airbus H175 by the GFS, and these Airbus H175 helicopters will be used at the new helipad at the NAH.  Also, the three Super Puma AS332 L2 helicopters were entered into retirement starting from 7th April 2020.  Relevant confirmation from GFS is given in Appendix 5H-1.

5.6.3.2       The new Airbus H175 helicopters will be equipped with more advanced engines resulting in quieter flight noise compared with the Super Puma AS332 L2 and Dauphin EC155 B1.  The Airbus H175 will comply with the latest standards on noise for helicopters as stipulated by the International Civil Aviation Organization (ICAO).  The ICAO has stipulated noise standards for lateral movements of helicopters, including approach, take-off and flyover.  The maximum Effective Perceived Noise Levels (EPNLs) for helicopters¡¦ lateral movements operating at full load conditions is used as the noise certification standard adopted by the ICAO Council.  The relevant noise certificate for the Airbus H175 with advice from GFS are presented in Appendix 5D and the EPNLs data are summarised in Table 5.8.

Table 5.8      Noise Data of Airbus H175 ¡V Lateral Movements

Operation Mode

Reference Distance, m

Noise Level

EPNL, EPNdB [1]

Lmax, dB(A) [2]

Approach

120

95.1

82.1

Take-off

150

89.8

76.8

Flyover

150

91.0

78.0

Note:

1.       The EPNLs are determined under conditions prescribed in Chapter 8 and Appendix 4 of Annex 16 of ICAO, and prescribed in 14 CFR 36 Appendix.

2.       Lmax = ENPL ¡V 13 dB(A) with reference to the ¡§Transportation Noise Reference Book¡¨ (P. M. Nelson, 1987, England: Butterworths).

5.6.3.3       However, the noise data for non-lateral movements are not available in the Noise Certificate for the Airbus H175.  In order to obtain representative noise data for non-lateral movements of the Airbus H175 for assessment purposes, a helicopter noise survey was carried out on 22 May 2019 at Lo Wu Shooting Range.  The detailed helicopter noise survey report is presented in Appendix 5E, and the measurement results are summarised in Table 5.9.

Table 5.9      Noise Measurement Results of Airbus H175 ¡V Non-lateral Movements

Operation Mode

Reference Distance, m

Measured Highest Noise Level Lmax of Airbus H175,  dB(A)

Highest Noise Level Lmax of Replaced Helicopters,  dB(A) [1]

Idling

150

75.4

82.0

Lift-off

150

82.4

89.0

Hovering

150

83.5

90.6

Touchdown

150

78.9

89.0

Note:

1.     As mentioned in Section 5.6.3.1, replaced helicopters include Super Puma AS332 L2 and Dauphin EC155 B1.  The highest noise levels among the replaced helicopters are represented by Super Puma AS332 L2 as extracted from the Table 4.10 of QMH Helipad EIA (Register No. AEIAR-208/2017).

 

5.6.3.4       Based on the noise measurement results for non-lateral movements of Airbus H175, it is found that its highest noise levels are around 7dB(A) ¡V 10dB(A) lower than that of the replaced helicopters.

 

5.6.4           Noise Impacts in Daytime ¡V Unmitigated Scenario

Helicopter and Helipad Buffer Distances

5.6.4.1       In order to keep the noise impact not higher than the daytime criterion Lmax 85dB(A), the minimum buffer distances required between identified residential NSRs and the Airbus H175 helicopter in different operation modes have been estimated.  Assuming no barrier correction, backward calculation of the equations in Section 5.6.2 and the noise data presented in Table 5.8 and Table 5.9 have been adopted.  NSRs outside the minimum buffer distances would not be subject to adverse helicopter noise impacts in the daytime.  The estimated buffer distances are presented in Table 5.10.

Table 5.10    Minimum Buffer Distance Required for Airbus H175

Operation Mode

Estimated Buffer Distance, m

Buffer Distance Required, m

Non-Lateral Movements at FATO of Helipad

Hovering

170

170

Lift-off

150

Touchdown

100

Idling

67

Lateral Movements along Flight Path

Approach

116

116

Take-off

79

Flyover

90

 

Lateral Movements of Airbus H175 along Flight Path

5.6.4.2       Based on the 116m buffer distance required from the flight path for lateral movements of the Airbus H175, a horizontal buffer zone of flight path has been determined.  The buffer zone of the flight path and the locations of the NSRs are shown in Figure 5.4a.

5.6.4.3       It is found that all representative NSRs are located outside the buffer zone.  Therefore, adverse helicopter noise impacts on all representative NSRs are not anticipated during lateral movements. 

Non-Lateral Movements of Airbus H175 at FATO of Helipad

5.6.4.4       Based on the 170m buffer distance from FATO of the helipad for non-lateral movements of the Airbus H175, a horizontal buffer zone of FATO has been determined.  The buffer zone of the FATO and the locations of NSRs are shown in Figure 5.4b.

5.6.4.5       It is found that three NSR, namely P01a and P01b for KTD Site 3E1 and P02a for KTD Site 3E2, fall within the horizontal FATO buffer zone.  Therefore, adverse helicopter noise impacts on these NSRs may be anticipated during non-lateral movements of the helicopter, subject to actual slant distances and presence of screening structures, if any.  All other representative NSRs are located outside the FATO buffer zone.

Predicted Noise Levels

5.6.4.6       The noise levels at NSRs due to helicopter operations have been predicted.  The highest predicted noise levels and the corresponding operation mode are summarised in Table 5.11 and detailed calculations are presented in Appendix 5F.

Table 5.11    Predicted Unmitigated Helicopter Noise Levels

NSR ID

Description

Highest Predicted Noise Level Lmax (1), dB(A)

Operation Mode

Compliance (Y/N)

Existing NSR

E01

Construction Industry Council Kowloon Bay Training Centre (CIC Kowloon Bay)

78

Approach

Y

Planned NSRs

P01a

Kai Tak Development Site 3E1 (KTD Site 3E1)

85

Approach

Y

P01b

86

Hovering

N

P01c

85

Approach / Hovering

Y

P02a

Kai Tak Development Site 3E2 (KTD Site 3E2)

85

Hovering

Y

P02b

84

Approach

Y

P03

Proposed Residential Development at Kerry Dangerous Goods Warehouse (Kowloon Bay) (NKIL 5813)

85

Approach

Y

P04

Kai Tak Development Site 4E1 (KTD Site 4E1)

83

Approach

Y

P05

Kai Tak Development Site 4A1 (KTD Site 4A1)

82

Approach

Y

P06

Kai Tak Development Site 4B1 (KTD Site 4B1)

85

Approach

Y

P07

Kai Tak Development Site 4B2 (KTD Site 4B2)

85

Approach

Y

P08

Kai Tak Development Site 4B3 (KTD Site 4B3)

84

Approach

Y

P09

Kai Tak Development Site 4B4 (KTD Site 4B4)

84

Approach

Y

Note:

1.     Bold noise levels indicate exceedance of the daytime noise criterion of Lmax 85 dB(A)

 

5.6.4.7       Based on the assessment results, the predicted highest helicopter noise levels range from Lmax 78 dB(A) to 86 dB(A) at the NSRs.  Daytime noise exceedances of 1dB(A) are predicted at NSR P01b during helicopter hovering at the proposed helipad.  It is predicted that approximate the top 12 floors of NSR P01b would be subjected to these noise exceedances.

5.6.5           Noise Mitigation Measures

5.6.5.1       In order to mitigate helicopter noise impact at the NSR, noise mitigation measures, including setback of helipad and installation of noise barrier and noise reducers on the top edge of the noise screening structure/barrier, have been considered, and proposed as far as practicable for the proposed helipad.  GFS has advised on the practicality of the mitigation measures in terms of helicopter operations, as documented in Appendix 5H-3.

Setback of Helipad

5.6.5.2       As mentioned in Section 2.4.2, the proposed helipad has been intentionally located on the western side of the rooftop of Acute Block of the NAH in order to reduce the noise impacts and direct lines of sight at nearby NSRs.  Setback has, therefore, been provided for the nearest NSRs, i.e. P01a and P01b of KTD Site 3E1.  The separation distances between the helipad and these NSRs have been maximised.

5.6.5.3       Besides, screening could be provided by the top edge of south-east roof structure of Acute Block for NSR P01a due to this setback.  Illustration of the screening is shown in Appendix 5G.  This setback has already been taken account of in the unmitigated scenario of the helicopter noise impact assessment.     

Screening by Noise Barrier and Noise Reducers

5.6.5.4       Installation of noise barrier at the rooftop of the Acute Block of the NAH can provide noise screening from the proposed helipad for nearby NSR, where the roof edge of Acute Block is not sufficient.  The noise barrier can reduce the direct lines of sight between the NSR and the helicopter during non-lateral movements on the helipad, achieving a minimum 5dB(A) noise reduction.  In order to further improve the noise shielding effect, noise reducers are proposed along the top edge of the noise screening structures, including the proposed noise barrier and the south-east roof structure of the Acute Block.  Noise reducers can improve the noise reducing performance of the noise screening structure by modifying the upper sound diffracting edge.  Specification of the proposed noise barrier and noise reducers are given below:

Noise Barrier

¡P         The noise barrier shall be made of materials having a surface mass density of at least 15kg/m2; and

¡P         The noise barrier shall be free of gaps or openings.

Noise Reducers

¡P         Insertion loss performance of the Noise Reducers shall be tested in accordance with ISO 10847 to achieve not less than 2dB(A); and

¡P         Sound absorption performance of the Noise Reducers shall be tested in accordance with ISO 354 to achieve not less than 0.7 at 400 Hz.

5.6.5.5       Nevertheless, the practicality on the proposed location of noise barrier and reducers on the roof of Acute Block have been considered.  The proposed noise barrier and noise reducers should not affect approaching and departure operations of helicopters.  Maximum height of the noise barrier and noise reducers is also subject to building height restriction under the current OZP.  Therefore, proposed horizontal and vertical extent of the noise barrier and noise reducers have been maximized under the above constraints.  

5.6.5.6       The extent of the proposed noise barrier and noise reducers are summarised in Table 5.12 and shown in Figure 5.5.  Illustration of screening by the noise barrier with noise reducer on top for NSR P01b is shown in Appendix 5G.  PlanD¡¦s advice on the acceptability of noise barrier proposed at the rooftop of the Acute Block is given in Appendix 2A.

Table 5.12    Summary of Proposed Noise Barrier and Noise Reducers

Location

Noise Mitigation Measure

Approx. Length (m)

Top Level

(mPD)

Approx. 10m from Helipad to the Southeast

Noise Barrier with Noise Reducer on Top

21.6

+123.9[1]

Top Edge of Southeast Roof Structure of Acute Block

Noise Reducer

89.5

Min. +110.0[2]

Note:

1.       Around 4.75m above the proposed helipad surface at +119.15 mPD.

2.       Based on the latest information provided by the Architectural Consultant for the design of the NAH, the level of the south-east roof of Acute Block is +110.0mPD.  However, an additional solid structure, such as a solid wall, might be proposed on and along the south-east roof edge, and its height is not confirmed at the time of preparing this EIA report and subject to further design of Acute Block.  Nonetheless, it is agreed that the noise reducer should be mounted on the top of the highest solid structure on the roof at the south-east side.  Therefore, it is conservatively assumed that the minimum level of this noise reducer is +110.0mPD.  In case the additional solid structure is proposed, the noise reducer will be proposed on top of it, subject to the height constraints as mentioned in Section 5.6.5.5.

5.6.6           Noise Impacts in Daytime ¡V Mitigated Scenario

5.6.6.1       With the implementation of the above mitigation measures, the mitigated noise levels at the NSRs due to helicopter operations associated with the proposed helipad have been predicted.  The highest predicted noise levels and the corresponding operation mode are summarised in Table 5.13 and detailed calculations are presented in Appendix 5F.

Table 5.13    Predicted Mitigated Helicopter Noise Levels

NSR ID

Description

Highest Predicted Noise Level Lmax, dB(A)

Operation Mode

Compliance (Y/N)

Existing NSR

E01

Construction Industry Council Kowloon Bay Training Centre (CIC Kowloon Bay)

78

Approach

Y

Planned NSRs

P01a

Kai Tak Development Site 3E1 (KTD Site 3E1)

85

Approach

Y

P01b

85

Approach

Y

P01c

85

Approach / Hovering

Y

P02a

Kai Tak Development Site 3E2 (KTD Site 3E2)

85

Hovering

Y

P02b

84

Approach

Y

P03

Proposed Residential Development at Kerry Dangerous Goods Warehouse (Kowloon Bay) (NKIL 5813)

85

Approach

Y

P04

Kai Tak Development Site 4E1 (KTD Site 4E1)

83

Approach

Y

P05

Kai Tak Development Site 4A1 (KTD Site 4A1)

82

Approach

Y

P06

Kai Tak Development Site 4B1 (KTD Site 4B1)

85

Approach

Y

P07

Kai Tak Development Site 4B2 (KTD Site 4B2)

85

Approach

Y

P08

Kai Tak Development Site 4B3 (KTD Site 4B3)

84

Approach

Y

P09

Kai Tak Development Site 4B4 (KTD Site 4B4)

84

Approach

Y

 

5.6.6.2       With the implementation of the mitigation measures, the predicted highest helicopter noise levels range from Lmax 78 dB(A) to 85 dB(A) at the NSRs.  All NSRs predicted with exceedance of daytime helicopter noise criteria in the unmitigated scenario, i.e. approximate the top 12 floors of NSR P01b, could be protected by the direct noise mitigation measures.  Thus, adverse helicopter noise impacts at the NSRs during the daytime period are not anticipated. 

5.6.6.3       Noise contours, in terms of Lmax at four different mPD levels including the general ground level, and the levels of lowest, middle and the highest representative NSRs, are presented in Figure 5.6a to Figure 5.6d to show the distribution of the highest predicted helicopter noise levels among all non-lateral operation modes under mitigated scenario.  While noise contours for highest predicted helicopter noise levels among all lateral operation modes are presented in Figure 5.7a to Figure 5.7d.

5.6.7           Noise Impacts in Evening and Night-time

5.6.7.1       Since there are no relevant noise criteria in the TM-EIAO, nor in any overseas/ international guidelines applicable to emergency helicopter operations in the evening and night-time periods, the helicopter noise impact during such time periods has not been quantitatively assessed.  As mentioned in Section 5.2.3.5, the emergency helicopter operations during the evening and night-time periods are generally exempted from flight restrictions based on international practices.

5.6.7.2       Nonetheless, all practicable noise mitigation measures have been exhausted and adopted at the proposed helipad to minimise the helicopter noise.  The new Airbus H175 helicopters with lower noise levels have been adopted by the GFS.  The design and selection of flight paths have been optimised to avoid flying over the noise sensitive areas.  The setback of the helipad and installation of noise barrier and noise reducers have, also, been utilised to provide screening and noise attenuation.  The proposed helipad has been designed and its operation has been planned in a practicable manner to avoid adverse helicopter noise impact.   

5.6.7.3       In accordance with the Civil Aviation (Aircraft Noise) Ordinance (Cap. 312), if the Director-General of Civil Aviation considers it appropriate, for the purpose of avoiding, limiting or mitigating the effect of noise and vibration connected with the taking off or landing of aircraft at an aerodrome, to prohibit aircraft from taking off or landing, or to limit the number of occasions on which they may take off or land, at an aerodrome during certain periods, he may by notice in the Gazette to prohibit aircraft of descriptions specified in the notice from taking off or landing at the aerodrome (otherwise than in an emergency) during periods so specified; or specify the maximum number of occasions on which aircraft of descriptions so specified may be permitted to take off or land at the aerodrome (otherwise than in an emergency) during periods so specified.  Since the use of the proposed helipad at NAH is for emergency service, which will be on an as needed basis that cannot be controlled, restrictions such as limiting the number of helicopter flights in evening and night-time periods or restrictions on the operating hours of the helipad are not practical. The proposed helipad at NAH will be available 24 hours a day for emergency uses with no scheduled helicopter operation.  As mentioned in Section 5.6.1.6, the evening and night-time emergency helicopter landings at the PYNEH were one flight about more than every ten days and eight days respectively on average and the frequency would be expected to be less for the NAH.  The longest duration among different operation modes of helicopter is 5 minutes.  According to the QMH Helipad EIA, the noise complaints about the helipad operation of TMH and PYNEH were rarely received and total 7 noise complaints were received by HA and CAD in the years between 2011 to 2015, as presented in Table 5.14.  From 2016 to 2019, there were 5 noise complaints received by CAD about the helipad operation of PYNEH.  It showed the general understanding to such critical services and tolerance to the emergency helicopter operation within the community.

Table 5.14    Statistics of Helicopter Noise Complaint of TMH and PYNEH

Hospital

Commencement Year

No. of Noise Complaints Received by HA

No. of Noise Complaints Received by CAD

2011 - 2015 [1, 2]

2011 -  2015 [1]

2016 - 2019

TMH

1992

0

0

0

PYNEH

2004

1

6

5

Note:

1.       Data are extracted from the QMH Helipad EIA (Register No. AEIAR-208/2017)

2.       As advised by HA, the statistics of helicopter noise complaints received by HA in 2016-2019 are not available.

 

5.6.8           Cumulative Helicopter Noise Impacts

5.6.8.1       As advised by GFS, there is no other existing helipads or regular helicopter flight routes identified in the vicinity of the proposed helipad.

5.6.8.2       However, it is noted that the GFS Kai Tak Division (GFS KTD) is planned at the tip of the ex-Kai Tak Runway, which is about 1.5km to the south-east of the NAH site.  GFS have confirmed that the flight paths of the proposed helipad and the GFS KTD would not overlap with each other concurrently for flight safety reasons.  Communications between helicopters and the GFS control base will be on-going throughout all flight operations to ensure the availability of flight paths.  Hence, cumulative helicopter noise impacts are not anticipated.

5.6.9           Evaluation of Residual Helicopter Noise Impacts

5.6.9.1       The proposed helipad has been designed and its operation has been planned in practicable manner to minimise helicopter noise impact.  A new helicopter fleet with quieter operational noise levels has been adopted by the GFS.  Flight sectors have been chosen for helicopter movements and the flight paths have been designed to maintain buffer distances from the NSRs.  With the implementation of the proposed practicable mitigation measures, including the setback of helipad, noise barrier and noise reducers, helicopter noise impacts on the representative NSRs have been mitigated as far as practicable.  Also, the predicted helicopter noise levels comply with the relevant helicopter noise standard as detailed in Table 5.2.

5.6.9.2       Typical flight height of the GFS¡¦s helicopter during flyover is 1500ft above mean sea level and the duration of the flyover noise event is about 2-3 seconds.  Under normal circumstances, the duration of helicopter idling at the proposed helipad will not be more than 5 minutes for casualty handover.  Noise event of hovering at a height around 2.5m above the helipad will be within 5 seconds before touchdown or after lift-off.

5.6.9.3       The helicopter operation for emergency medical services provided by GFS occurs randomly over the year.  With reference to the past helicopter flight records, the average number of daily emergency helicopter operation was less than one.  The operation during daytime period is about once every one to two days on average, and the operation during evening and night-time period are expected not more than one flight in ten days and eight days on average respectively.

5.6.9.4       Based on the above, it is considered that all practicable noise mitigation measures have been exhausted and adopted in the operation design of the proposed helipad.  Helicopter noise impacts have been minimised, and thus, adverse residual noise impacts are not anticipated during the operational phase of the Project.

5.6.10         Assessment of Side Effects and Constraints

5.6.10.1     Due to the inclusion of proposed noise barrier and noise reducers to the Project, potential visual and air quality impacts are identified as the potential side effects.  Visual Impact Assessment for the Project and the associated structures, including the proposed noise barrier and noise reducers are detailed in Section 7.  Air Quality Impact Assessment in Section 3 has also taken into account the proposed noise barrier.

5.6.10.2     As mentioned in the Section 5.6.5.1 and Appendix 5H-3, GFS has no objection on the noise mitigation measures in terms of helicopter operation.  Potential constraint on the NAH building itself and other developments nearby due to the inclusion of proposed noise barrier and noise reducers is not anticipated.

5.7                Environmental Monitoring and Audit

5.7.1.1       As no construction phase noise exceedances are anticipated, therefore, construction phase noise monitoring is not considered as being required.  However, regular site inspections during the construction phase, of at least once per week, are recommended to ensure good working practices are being effectively implemented to minimise any construction noise as far as possible.

5.7.1.2       During the operational phase, with the implementation of mitigation measures, there would be no noise exceedances of the relevant noise criterion at the representative NSRs.  Also, the proposed helipad is solely for emergency use only with no scheduled flights and the anticipated frequency of usage is less than once per day.  As such, operational phase noise monitoring is not considered necessary.

5.7.1.3       The Environmental Monitoring and Audit (EM&A) requirements and implementation of noise mitigation measures are detailed in the stand-alone Project EM&A Manual.

5.8                Conclusions

5.8.1.1       The potential noise impacts associated with the Project in the construction and operational phases have been assessed.

5.8.1.2       The noise impacts arising from daytime construction activities for the Project have been evaluated.  No evening or nighttime construction works will be scheduled.  Cumulative construction noise impacts with concurrent project have also been considered.  It is shown that the predicted noise levels at the one representative NSR will comply with the relevant construction noise criterion and no specific mitigation measures will be required.  Nonetheless, the adoption of good site practices and use of quieter PMEs have been recommended to minimise the construction noise impacts.  Hence, no adverse construction noise impacts are anticipated.

5.8.1.3       In the operational phase, the noise impacts arising from GFS¡¦s helicopter operation associated with the Project have been evaluated.  The helicopter noise impact assessment was conducted using a conservative approach under the worst-case scenario.  All practicable measures, including carefully chosen flight sectors and one-way-direction for approaching and take-off subject to flight condition, and maintaining buffer distance for flight paths to fly away from NSRs, have been utilized for helicopter operation.  With the implementation of direct noise mitigation measures, including setback of helipad and installation of noise barrier and noise reducers, the helicopter noise impacts have been minimized, and the predicted helicopter noise levels at the representative NSRs are within the criteria in Table 5.2.  Nonetheless, the emergency medical helicopter operation occurs randomly over the year, it is anticipated that the average helipad usage will be less than once per day, while the duration of each emergency use will be about 7 minutes as detailed in Section 5.6.1.4. 

5.8.1.4       The proposed helipad in NAH will share the landing frequency for emergency medical services at the existing and planned helipad facilities at public hospitals.  The Project enables point-to-point direct and speedy transfers of patients / survivors that require special care to the NAH.  It is critical to lifesaving and significant for provision of timely treatment to patients.  It is also an essential infrastructure development in Hong Kong to cater for the change in population and to maintain a high quality of medical services which shall be generally agreed by the public.