3 NoISE

Introduction

3.1 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 the Project is presented.

Noise Parameters

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. For all other time periods, L_eq _{(5 minutes)} should be employed for comparison with the NCO criteria.

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 B2 for reference. The ET Leader may modify the data record sheet for this EM&A programme, of which the format should be agreed by the ER and the IEC.

Monitoring Equipment and Methodology

3.4 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.

3.5 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.

3.6 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

3.7 Based on the EIA study, the designated location for construction noise monitoring is listed in Table 3.1 and shown in Figure Nos. NEX2213/C/331/ENS/M62/520.

Table 3.1 Noise Monitoring Stations during Construction Phase

Identification No.	NSR ID in EIA Report	Construction Noise Monitoring Station
NM1	CH4	Marco Polo Mansion

3.8 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.

3.9 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

3.10 The ET should carry out baseline noise monitoring prior to the commencement of the construction works. The baseline noise levels should be carried out daily for a period of at least two weeks. Before commencing the baseline monitoring, the ET should develop and submit to the IEC the baseline monitoring programme such that the IEC can conduct on-site audit to ensure accuracy of the baseline monitoring results.

3.11 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.

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

Impact Monitoring

3.13 Noise monitoring should be carried out at the designated monitoring station 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.

3.14 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.

3.15 In the case of non-compliance with the construction noise criteria, more frequent monitoring, as specified in Event and Action Plan in Table 3.3 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

3.16 The Action and Limit levels for construction noise are defined in Table 3.2. Should non-compliance of the noise quality criteria occur, actions in accordance with the Event and Action Plan in Table 3.3 should be taken.

Table 3.2 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)*

Notes: * 70 dB(A) and 65 dB(A) for schools during normal teaching periods and school examination periods, respectively.

3.17 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 3.3 Event and Action Plan for Construction Noise Monitoring

EVENT	ACTION
EVENT	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 with the IEC and Contractor on remedial measures required 5. Increase monitoring frequency to check mitigation effectiveness (The above actions should be taken within 2 working days after the exceedance is identified)	1. Review the investigation results submitted by the ET 2. Review the proposed remedial measures by the Contractor and advise the ER accordingly 3. Advise the ER on the effectiveness of the proposed remedial measures (The above actions should be taken within 2 working days after the exceedance is identified)	1. Confirm receipt of notification of failure in writing 2. Notify Contractor 3. In consolidation with the IEC, agree with the Contractor on the remedial measures to be implemented 4. Supervise the implementation of remedial measures (The above actions should be taken within 2 working days after the exceedance is identified)	1. Submit noise mitigation proposals to IEC and ER 2. Implement noise mitigation proposals (The above actions should be taken within 2 working days after the exceedance is identified)
Limit Level	1. Inform IEC, ER, EPD and Contractor 2. Repeat measurement to confirm findings 3. Increase monitoring frequency 4. Identify source and investigate the cause of exceedance 5. Carry out analysis of Contractor’s working proceduresDiscuss with the IEC, Contractor and ER on remedial measures require 6. Assess effectiveness of Contractor’s remedial actions and keep IEC, EPD and ER informed of the results 7. If exceedance stops, cease additional monitoring (The above actions should be taken within 2 working days after the exceedance is identified)	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 (The above actions should be taken within 2 working days after the exceedance is identified)	1. Confirm receipt of notification of failure in writing 2. Notify Contractor 3. In consolidation with the IEC, agree with the Contractor on the remedial measures to be implemented 4. Supervise the implementation of remedial measures 5. If exceedance continues, consider stopping the Contractor to continue working on that portion of work which causes the exceedance until the exceedance is abated (The above actions should be taken within 2 working days after the exceedance is identified)	1. Take immediate action to avoid further exceedance 2. Submit proposals for remedial actions to IEC and ER within 3 working days of notification 3. Implement the agreed proposals 4. Submit further proposal if problem still not under control 5. Stop the relevant portion of works as instructed by the ER until the exceedance is abated (The above actions should be taken within 2 working days after the exceedance is identified)