3 NOISE

3.1 Introduction

3.1.1 In this section, the requirements, methodology, equipment, monitoring locations, criteria and protocols for the monitoring and audit of noise impacts during the construction phase of all WDII works, including entrustment works from HyD, are presented. As the construction noise is the prime concern, noise levels shall be monitored to evaluate the construction noise impact during the construction phase.

3.2 Noise Parameters

3.2.1 The construction noise level shall be measured in terms of the A-weighted equivalent continuous sound pressure level (L_eq). L_eq _{(30 minutes)} shall be used as the monitoring parameter for the time period between 0700 and 1900 hours on normal weekdays. For all other time periods, L_eq _(5
minutes) shall be employed for comparison with the Noise Control Ordinance (NCO) criteria.

3.2.2 As supplementary information for data auditing, statistical results such as L₁₀ and L₉₀ shall also be obtained for reference. A sample data record sheet is shown in Appendix B2 for reference.

3.3 Monitoring Equipment

3.3.1 As referred to in 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 shall be used for carrying out the noise monitoring. Immediately prior to and following each noise measurement the accuracy of the sound level meter shall 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 calibration level from before and after the noise measurement agree to within 1.0 dB.

3.3.2 Noise measurements should not be made in accordance with standard acoustical principals and practices in relation to weather conditions.

3.3.3 The ET is responsible for the provision of the monitoring equipment. He shall 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 shall be clearly labelled.

3.4 Monitoring Locations

3.4.1 The locations of construction noise monitoring stations are summarised in Table 3.1 and shown in Figure 3.2. These locations represent the worst affected sensitive receivers at Wan Chai and Causeway Bay during construction.

Table 3.1 Noise Monitoring Stations during Construction Phase

Area	Noise Monitoring Station	Noise Monitoring Location
Wan Chai	M1	Causeway Bay Centre
Causeway Bay	M2	Marco Polo Mansion
Causeway Bay	M3	Belle House

3.4.2 Owing to the nature of the works under the project, construction activities will shift from one location to another from time to time. The ET shall select the monitoring locations from those in Table 3.1 based on the locations of the construction activities and seek approval from ER and agreement from the IC(E) and EPD to the proposal. The monitoring locations should be chosen based on the following criteria:

· at locations close to the major site activities which are likely to have noise impacts;

· close to the most affected existing noise sensitive receivers; and

· for monitoring locations located in the vicinity of the sensitive receivers, care should be taken to cause minimal disturbance to the occupants during monitoring.

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

3.5 Baseline Monitoring

3.5.1 The ET shall carry out baseline noise monitoring prior to the commencement of the construction works. The baseline monitoring shall be carried out daily for a period of at least two weeks. A schedule on the baseline monitoring shall be submitted to the IC(E) for approval before the monitoring starts.

3.5.2 There shall not be any construction activities in the vicinity of the stations during the baseline monitoring.

3.5.3 In exceptional cases, when insufficient baseline monitoring data or questionable results are obtained, the ET shall liaise with the IC(E) and EPD to agree on an appropriate set of data to be used as a baseline reference and submit to the ER for approval.

3.6 Impact Monitoring of Construction Noise Impact

3.6.1 Noise monitoring shall be carried out at all the designated monitoring station. The monitoring frequency shall depend on the scale of the construction activities. The following is an initial guide on the regular monitoring frequency for each station on a weekly basis when noise generating activities are underway:

(a) one set of measurements between 0700 and 1900 hours on normal weekdays.

3.6.2 General construction work carryied out during restricted hours is controlled by Construction Noise Permit (CNP) system under the NCO.

3.6.3 If a school exists near the construction activity, noise monitoring shall be carried out at the monitoring stations for the schools during the school examination periods. The ET Leader shall liaise with the school’s personnel and the Examination Authority to ascertain the exact dates and times of all examination periods during the course of the contract.

3.6.4 In case of non-compliance with the construction noise criteria, more frequent monitoring, as specified in the Action Plan in Table 3.3, shall be carried out. This additional monitoring shall be continued until the recorded noise levels are rectified or proved to be irrelevant to the construction activities.

3.6.5 A schedule on the compliance monitoring shall be submitted to the ER and IC(E) for approval before the monitoring starts.

3.7 Event and Action Plan for Construction Noise

3.7.1 The Action and Limit levels for construction noise are defined in Table 3.2. Should non-compliance of the criteria occur, action in accordance with the Action Plan in Table 3.3 shall be carried out.

Table 3.2 Action and Limit Levels for Construction Noise

Time Period

Action Level

Limit Level

0700 - 1900 hours on normal weekdays

When one documented complaint is received

75 dB(A) *

Note : If works are to be carried out during restricted hours, the conditions stipulated in the construction noise permit issued by the Noise Control Authority have to be followed.

* Reduce to 70 dB(A) for schools and 65 dB(A) during school examination periods.

Table 3.3 Event / Action Plan for Construction Noise

EVENT

ACTION

IC(E)

CONTRACTOR

Action Level

1. Identify source, investigate the causes of exceedance and propose remedial measures;

2. Notify IC(E) and Contractor;

3. Report the results of investigation to the IC(E), ER and Contractor;

4. Discuss with the 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 IC(E);

2. Implement noise mitigation proposals.

Limit Level

1. Identify source;

2. Inform IC(E), ER, EPD and Contractor;

3. Repeat measurements 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 IC(E), ER and EPD the causes and actions taken for the exceedances;

7. Assess effectiveness of Contractor’s remedial actions and keep IC(E), 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 Contractors 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 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 IC(E) within 3 working days of notification;

3. Implement the agreed proposals;

4. 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.

3.8 Noise Mitigation Measures

Construction Phase

3.8.1 The Contractor is recommended to adopt quiet powered mechanical equipment (PME) for the following construction tasks of WDII:

· Flyover Road P2 to Fenwick Pier near the HKAPA and the Art Centre;

· Road P2 near the HKAPA, the Art Centre and the HKCEC Extension;

· HKCEC roads;

· Local access roads near the HKAPA and the Art Centre;

· Wan Chai North Public Transport Interchange;

· Demolition of HKCEC East Bridge (WCR2E) and West Bridge (HKCEC2);

· Demolition of ferry structure and Reprovision of East Pier and West Pier;

· Hung Hing Road Flyover construction;

· Drainage culverts in CBR1E, CBR1W, CBR2E, WCR1, WCR2E and HKCEC2;

· Cross Harbour water mains - land section; and

· Cooling water intake pipelines in HKCEC1 near HKAPA, HKCEC2W near HKAPA and Art Centre and CBR1 near Riviera Mansion.

3.8.2 In order to further reduce construction noise impacts on HKAPA, movable noise barriers should be adopted for Cross Harbour Watermains land section where the works site is close to HKAPA; and HKCEC roads where the works sites are close to HKCEC Extension.

3.8.3 CWB tunnel works which are entrusted by the CWB & IECL Project to the WDII Project will require adoption of quiet PMEs for the following tasks:

· CWB tunnel in HKCEC1, HKCEC2E, HKCEC2W, WCR1, WCR2E, WCR2W and WCR3W;

· Piling, tunnel and deck construction in the MTR tunnel crossing area near HKAPA and Art Centre.

3.8.4 The construction tasks adopting quiet PMEs under the CWB & IECL Project itself are listed as follows:

· Demolition of existing IEC structure, bridge foundation, deck formation, road formation and earthworks, road paving at the IECL section;

· Tunnel buildings.

3.8.5 In addition, there are also many good site practices recommended as follows:

· only well-maintained plant should be operated on-site and plant should be serviced regularly during the construction program;

· silencers or mufflers on construction equipment should be utilised and should be properly maintained during the construction program;

· mobile plant, if any, should be sited as far away from NSRs as possible;

· machinery and plant (such as trucks) that may be in intermittent use should be shut down between work periods or should be throttled down to a minimum;

· plant known to emit noise strongly in one direction should, where possible, be orientated so that the noise is directed away from nearby NSRs; and

· material stockpiles and other structures should be effectively utilised, where practicable, in screening noise from on-site construction activities.

3.8.6 If the above measures are not sufficient to restore the construction noise quality to acceptable levels upon the advice of ET Leader, the contractor shall liaise with the ET Leader to identify further mitigation measures. They shall be proposed to ER for approval, and the contractor shall then implement these additional mitigation measures.

3.8.7 The implementation for the recommended mitigation measures is presented in Appendix A.

Operational Phase