3. AIRBORNE NoISE

Introduction

3.1 In this section, the requirements, methodology, equipment, monitoring locations, criteria and protocols for the monitoring and audit of airborne noise impacts during the construction and operation phases of the Project are presented.

Construction Noise

Noise Parameters and Criteria

3.2 The construction noise level should be measured in terms of the A-weighted equivalent continuous sound pressure level (L_eq).  L_{eq (30 minutes)} should be used as the monitoring parameter for the time period between 0700 and 1900 hours on normal weekdays. 

3.3 Supplementary information for data auditing and statistical results such as L₁₀ and L₉₀ should also be obtained for reference.  A sample data record sheet is shown in Appendix B for reference.

3.4 Whilst the Noise Control Ordinance (NCO) does not provide for the statutory control of construction activities occurring on weekdays during normal working hours (i.e. Monday to Saturday inclusive 0700-1900 hours), the daytime criterion of L_{eq(30 minute)} 75dB(A) stipulated in Annex 5 of the Technical Memorandum on Environmental Impact Assessment Process (EIAO-TM) is adopted as the compliance criterion for all residential dwellings; and the daytime standards of L_{eq(30 minute)} 70dB(A) and L_{eq (30 minute)} 65dB(A) are adopted for all educational institutions during normal school days and examination periods, respectively.

3.5 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 Acceptable Noise Levels (ANLs) during restricted hours are dependent on the Area Sensitivity Rating of the NSRs. The relevant ANLs are provided in Table 3.1.

Table 3.1          Acceptable Noise Levels (ANLs)

Time Period	Area Sensitivity Rating, dB(A)
	A	B	C
All days during the evening (1900-2300 hours) and general holidays (including Sundays) during the day and evening (0700-2300 hours)	60	65	70
All days during the night-time (2300-0700)	45	50	55

Monitoring Equipment and Methodology

3.6 As referred to the requirements of the Technical Memorandum (TM) issued under the NCO, sound level meters in compliance with the International Electrotechnical Commission Publications 651: 1979 (Type 1) and 804: 1985 (Type 1) specifications should be used for carrying out the noise monitoring.  Immediately prior to and following each noise measurement the accuracy of the sound level meter should be checked using an acoustic calibrator generating a known sound pressure level at a known frequency.  Measurements may be accepted as valid only if the difference between calibration levels obtained before and after the noise measurement is less than 1.0 dB.

3.7 Noise measurements should not be made in the presence of fog, rain, wind with a steady speed exceeding 5ms^-1 or wind with gusts exceeding 10ms^-1. The wind speed should be checked with a portable wind speed meter capable of measuring wind speeds in m/s.

3.8 The ET Leader is responsible for the provision of the monitoring equipment.  He should ensure that sufficient noise measuring equipment and associated instrumentation are available for carrying out the baseline monitoring, regular impact monitoring and ad hoc monitoring.  All the equipment and associated instrumentation should be clearly labelled.

Noise Monitoring Locations

3.9 Based on the EIA study, the designated locations for construction noise monitoring are listed in Table 3.2 and shown in Figure Nos. NOL/ERL/300C/XRL/ENS/M62/200 to 214.

Table 3.2          Noise Monitoring Stations during Construction Phase

Identification No.	NSR ID in EIA Report	Construction Noise Monitoring Station
CN1	MP3	No. 166 Mai Po San Tsuen
CN2	MP2	Mai Po San Tsuen Village House
CN3	NT2	Yau Tam Mei Village House
CN4	NT3	Yau Tam Mei Village House
CN5	TP1	Kong Tai Road Village House
CN6	TP2	Kong Tai Road Village House
CN7	SS9	House 93, Seasons Villas
CN8	SS10	DD110 LOT 482, Wang Toi Shan
CN9	SS7	Leung Uk Tsuen Village House
CN10	SS11	Leung Uk Tsuen Squats
CN11	SS4	Leung Uk Tsuen Village House
CN12	SS1	630 Sheung Tsuen
CN13	TU2	No. 489H Tse Uk Tsuen
CN14	TU1	Tse Uk Tsuen
CN15	PH3	No. 305B, Sheung Tsuen San Tsuen Village House
CN16	PH1	DD 114 LOT 1405 Sheung Tsuen
CN17	SM2	Tsuen Wan Lutheran School
CN18	SM1	Sau Shan House, Cheung Shan Estate
CN19	SY1	No. 168, Yau Ma Hom Resite Village
CN20	KC2	No. 1, Ha Kwai Chung Village
CN21	ML1	Po Leung Kuk Tong Nai Kan College
CN22	-	Block I, Lai Chi Kok Reception Centre
CN23	NC13	HKIVE Haking Wong Waterfront Annex
CN24	NC17	St. Andrew Primary School
CN25	NC11	Tack Ching Girls' Secondary School
CN26	NC9	Ying Wah College
CN27	NC6	Cheong Yat House, Nam Cheong Estate
CN28	NC2	Tower 6, Harbour Green
CN29	MK1	Yaumati Catholic Primary School (Hoi Wang Road)
CN30	WK3	Man King Building, 46-48 Man Wai Street
CN31	WK4	Tower 6, Sorrento
CN32	WK8	Tower 3, The Waterfront
CN33	WK14	Moon Tower, The Arch
CN34	WK7a	Tsim Sha Tsui Fire Station

3.10 The status and location of noise sensitive receivers may change after this manual is issued.  In such event, and if changes to the monitoring locations are considered necessary, the ET Leader should propose alternative monitoring locations and seek agreement from the IEC on the proposal.  When alternative monitoring locations are proposed, the monitoring locations should be chosen based on the following criteria:

§ Monitoring at sensitive receivers close to the major site activities that are likely to have noise impacts;

§ Monitoring close to the noise sensitive receivers as defined in the Technical Memorandum; and

§ Assurance of minimal disturbance to the occupants during monitoring in the vicinity of sensitive receivers.

3.11 The monitoring station should normally be at a point 1m from the exterior of the noise sensitive facade and be at a position 1.2m above ground.  If there is a problem with access to the normal monitoring position, an alternative position should be chosen, and a correction to the measurement results should be made.  For reference, a correction of +3dB(A) should be made to free-field measurements.  The ET Leader should agree with the IEC on the monitoring position and the corrections adopted.  Once the positions for the monitoring stations are chosen, the baseline monitoring and the impact monitoring should be carried out at the same positions.

Baseline Monitoring

3.12 The ET should carry out baseline noise monitoring prior to the commencement of the construction works.  The baseline noise levels should be measured for a continuous period of at least 14 consecutive days at a minimum logging interval of 30 minutes for daytime (between 0700 and 1900 hours of normal weekdays) and 15 minutes (as three consecutive L_{eq, (5 minutes)} readings) for evening time (between 1900 and 2300 hours on normal weekdays), general holidays including Sundays (between 0700 and 2300 hours) and night-time (between 2300 and 0700 on all days). The L_eq, L₁₀ and L₉₀ should be recorded at the specified interval.  A schedule for the baseline monitoring should be submitted to the IEC for approval before the monitoring starts.  

3.13 There should not be any construction activities in the vicinity of the monitoring stations during the baseline monitoring.  Any non-project related construction activities in the vicinity of the monitoring stations during the baseline monitoring should be noted and the source and location of such activities should be recorded.

3.14 In exceptional cases, when baseline monitoring data obtained are insufficient or questionable, the ET Leader should liaise with the IEC and EPD to agree on an appropriate set of data to be used as the baseline reference.

Impact Monitoring

3.15 Noise monitoring should be carried out at all the designated monitoring stations when there are Project-related construction activities being undertaken within a radius of 300m from the monitoring stations.  The monitoring frequency should depend on the scale of the construction activities.  An initial guide on the monitoring is to obtain one set of 30-minute measurement at each station between 0700 and 1900 hours on normal weekdays at a frequency of once a week when construction activities are underway.

3.16 Any General construction work carried out during restricted hours is controlled by Construction Noise Permit (CNP) under the NCO.

3.17 If a school is located near the construction activities, noise monitoring should be carried out at the monitoring stations for the school during school examination periods. The ET Leader should liaise with the school administration and the Hong Kong Examinations and Assessment Authority to ascertain the exact dates and times of all examinations during the construction phase of the Project.

3.18 In the case of non-compliance with the construction noise criteria, more frequent monitoring, as specified in Event and Action Plan in Table 3.4 should be carried out.  This additional monitoring should be continued until the recorded noise levels show that the non-compliance is rectified or proved to be irrelevant to the Project-related construction activities.

Event and Action Plan

3.19 The Action and Limit levels for construction noise are defined in Table 3.3. Should non-compliance of the noise quality criteria occur, actions in accordance with the Event and Action Plan in Table 3.4 should be taken.

Table 3.3 Action and Limit Levels for Construction Noise

Time Period	Action	Limit
0700-1900 hours on normal weekdays	When one documented complaint is received	75 dB(A) for residential premises
		70 dB(A) for school and 65 dB(A) during examination period

3.20 To account for cases in which ambient noise levels, as identified by baseline monitoring, approach or exceed the stipulated Limit Levels prior to the commencement of construction, a Maximum Acceptable Impact Level, which incorporates the baseline noise levels and the identified construction noise Limit Level, may be defined and agreed with EPD. The amended level will be greater than 75 dB(A) and will represent the maximum acceptable noise level at a specific monitoring station. Correction factors for the effects of acoustic screening and/or architectural features of NSRs may also be applied as specified in the TM.

Table 3.4 Event and Action Plan for Construction Noise Monitoring

EVENT	ACTION
	ET	IEC	ER	CONTRACTOR
Action Level	1. Notify IEC, ER and Contactor 2. Carry out investigation 3. Report the results of investigation to the IEC, ER and Contactor 4. Discuss jointly with the ER and Contractor and formulate remedial measures 5. Increase monitoring frequency to check mitigation effectiveness	1. Review the analysed results submitted by the ET 2. Review the proposed remedial measures by the Contractor and advise the ER accordingly 3. Supervise the implementation of remedial measures	1. Confirm receipt of notification of failure in writing 2. Notify Contractor 3. Require Contractor to propose remedial measures for the analysed noise problem 4. Ensure remedial measures are properly implemented	1. Submit noise mitigation proposals to ER with copy to IEC and ET 2. Implement noise mitigation proposals
Limit Level	1. Notify IEC, ER, EPD and Contractor 2. Identify source 3. Repeat measurement to confirm findings 4. Increase monitoring frequency 5. Carry out analysis of Contractor’s working procedures to determine possible mitigation to be implemented 6. Inform IEC, ER, EPD the causes and actions taken for the exceedances 7. Assess effectiveness of Contractor’s remedial actions and keep IEC, EPD and ER informed of the results 8. If exceedance stops, cease additional monitoring	1. Discuss amongst ER, ET and Contractor on the potential remedial actions 2. Review Contractor’s remedial actions whenever necessary to assure their effectiveness and advise the ER accordingly 3. Supervise the implementation of remedial measures	1. Confirm receipt of notification of failure in writing 2. Notify Contractor 3. Require Contractor to propose remedial measures for the analysed noise problem 4. Ensure remedial measures are properly implemented 5. If exceedance continues, consider what portion of the work is responsible and instruct the Contractor to stop that portion of work until the exceedance is abated	1. Take immediate action to avoid further exceedance 2. Submit proposals for remedial actions to ER with copy to IEC and ET 3. Implement the agreed proposals 4. Revise and resubmit proposals if problem still not under control 5. Stop the relevant portion of works as determined by the ER until the exceedance is abated

Operational Noise – Fixed Plant

Maximum Permissible Sound Power Levels of Fixed Plant

3.21 The maximum permissible sound power levels of the identified fixed noise sources of the Project were predicted in the EIA report. The specified sound power levels should be implemented and refined by the Contractor as appropriate to ensure that the noise impact associated with the fixed plant operations would comply with the noise standards stipulated in the EIAO-TM and NCO.

Commissioning Test

3.22 Prior to the operation of the Project, the Contractor should conduct noise commissioning tests for all major fixed noise sources. The test should be carried out by a qualified person possessing at least 7 years of noise control experience and a corporate membership of Hong Kong Institute of Acoustics or equivalent. The noise commissioning test report should be submitted to the ET Leader and IEC for approval.

Operational Noise – Railway Operation

Noise Parameters and Criteria

3.23 To ensure that the operational airborne railway noise levels comply with the noise standards stipulated in the NCO, the ET should carry out railway noise commissioning tests at the potentially worst affected NSRs identified in the EIA study before the operation of the Project.

3.24 The IND-TM stipulates the appropriate acceptable noise levels (ANL) for airborne railway noise. The ANLs are dependent on area sensitivity rating (ASR) of the noise sensitive receivers and are shown in Table 3.5.

3.25 EIAO-TM also stipulates a maximum noise level of 85 dB(A) applying to the period from 2300 to 0700 hours.

Table 3.5 Operational Airborne Railway Noise Criteria

	Air-borne Railway Noise Criteria, dB(A)
NSRs Description	Day and Evening Periods (0900 to 2300 hrs)			Night-time Period (2300 to 0700 hrs)
	A	B	C	A	B	C
Churches/temples, schools, medical clinics, libraries and courts	60	65	70	[a]
Domestic premises, hotels and hospitals	60	65	70	50	55	60

Note:

[a] No sensitive use during this period.

Monitoring Equipment and Methodology

3.26 The monitoring equipment and methodology for operational airborne noise monitoring should be same as those recommended for construction noise monitoring.

Noise Monitoring Locations

3.27 Based on the EIA study, the potentially worst affected locations were designated for operational airborne noise monitoring as listed in Table 3.6 and illustrated in Figure No. NOL/ERL/300C/XRL/ENS/M62/215.

Table 3.6          Noise Monitoring Stations during Operation Phase

Identification No.	NSR ID in EIA Report	ASR	Operational Noise Monitoring Station
ON1	SS7	B	Leung Uk Tsuen Village House
ON2	SS10	B	DD110 LOT 482, Wang Toi Shan
ON3	SS15	B	Leung Uk Tsuen Squats

3.28 The status and location of noise monitoring locations may change after issuing this manual.  If such cases exist, the ET Leader should propose updated monitoring locations and seek approval from the ER and agreement from the IEC and EPD on the proposal.  When alternative monitoring locations are proposed, the monitoring locations should be chosen based on the following criteria:

§ Monitoring at sensitive receivers close to the major operation activities which are likely to have noise impacts;

§ Monitoring close to the noise sensitive receivers as defined in the Technical Memorandum; and

§ Assurance of minimal disturbance to the occupants during monitoring in the vicinity of sensitive receivers.

3.29 The monitoring station should normally be at a point 1m from the exterior of the noise sensitive facade and be at a position 1.2m above ground.  If there is a problem with access to the normal monitoring position, an alternative position should be chosen, and a correction to the measurements should be made.  For reference, a correction of +3dB(A) should be made to the free field measurements.  The ET Leader should agree with the IEC on the monitoring position and the corrections adopted. 

Commissioning Test

3.30 One set of 30-minute measurement at each monitoring station should be conducted during the daytime and evening period (0700 - 2300 hours), and night-time (2300 – 0100 hours).  Noise measurements of the A-weighted equivalent continuous sound pressure level (L_eq) should be made.  L_{eq (30 minutes)} should be used as the monitoring parameter.  Supplementary information for data auditing, statistical results, such as L_max, L₁₀ and L₉₀ should also be obtained for reference. 

Mitigation Measures

Construction Phase

3.31 The EIA report indicates that construction activities would cause noise exceedances at a few NSRs, and therefore, appropriate mitigation measures and good site practices are recommended. The Contractor should be responsible for the design and implementation of these measures. The implementation schedule for the recommended mitigation measures is presented in Appendix A.

3.32 In the event of exceedances or complaints, the Contractor should review the effectiveness of these mitigation measures and propose, design and implement alternative or additional measures as appropriate. The Contractor should liaise with the ET Leader on alternative or additional mitigation measures, provide them to ER for approval, and implement the mitigation measures.

Operation Phase

3.33 The mitigation measures recommended for the operation of the Project is presented in Appendix A. These measures should be reviewed and refined by the ET Leader if there are any major design changes during the detailed design phase such that the recommended measures are adequate for alleviating the potential operational noise impacts from SSS and ERS.