6.1 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 are presented.
6.2 Construction noise impacts from this Project are predicted at the identified Noise Sensitive Receivers (NSRs). Noise mitigation measures would be required to reduce noise levels to the stipulated standard. A noise monitoring programme shall be undertaken to verify such mitigation measures would be implemented properly.
6.3
The EIA findings confirmed that
proper designs of the crematorium would control the potential noise impact at
noise sensitive receivers within acceptable levels, thus operation phase noise monitoring
would be considered not necessary.
Nevertheless, the ET
shall carry out noise measurements at
6.4 The construction noise level shall be measured in terms of the A-weighted equivalent continuous sound pressure level (Leq). Leq (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, Leq (5 minutes) shall be employed for comparison with the Noise Control Ordinance (NCO) criteria.
6.5
Supplementary information for
data auditing, statistical results such as L10 and L90 shall also be obtained
for reference. A sample data record
sheet based on the one presented in the EM&A Guidelines for Development
Projects in
6.6 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.
6.7 Noise measurements shall not be made in fog, rain, wind with a steady speed exceeding 5 m/s or wind with gusts exceeding 10 m/s. The wind speed shall be checked with a portable wind speed meter capable of measuring the wind speed in m/s.
6.8 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.
6.9 The construction noise monitoring will be carried out at the staff quarters of Cape Collinson Crematorium as shown in Figure 6.1. This location would represent the worst affected sensitive receiver during construction.
6.10 The status and locations of noise sensitive receivers may change after issuing this manual. If such case exists, the ET Leader shall propose updated monitoring locations and seek approval from EPD and agreement from the ER and the IEC before baseline monitoring commences.
6.11 When alternative monitoring locations are proposed, the monitoring locations shall be chosen based on the following criteria:
(i) Monitoring at sensitive receivers close to the major site activities which are likely to have noise impacts;
(ii) Monitoring at the noise sensitive receivers as defined in the Technical Memorandum; and
(iii) Assurance of minimal disturbance to the occupants during monitoring.
6.12 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 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 shall be carried out at the same positions.
6.13 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. Before commencing the baseline monitoring, the ET shall develop and submit to the IEC the baseline monitoring programme such that the IEC can conduct on-site audit to check accuracy of the baseline monitoring results.
6.14 There shall not be any construction activities in the vicinity of the stations during the baseline monitoring.
6.15 In exceptional cases, when insufficient baseline monitoring data or questionable results are obtained, the ET Leader shall liaise with the ER, EPD and IEC to agree on an appropriate set of data to be used as a baseline reference and submit to the ER and IEC for agreement and EPD for approval.
6.16 Noise monitoring shall be carried out at all the designated monitoring stations. 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.
6.17 If construction works are extended to include works during the hours of 1900 – 0700 as well as public holidays and Sundays, additional weekly impact monitoring shall be carried out during respective restricted hours periods. Applicable permits under NCO shall be obtained by the Contractor.
6.18 In case of non-compliance with the construction noise criteria, more frequent monitoring, as specified in the Action Plan in Table 6.2, shall be carried out. This additional monitoring shall be continued until the recorded noise levels are rectified or demonstrated to be unrelated to the construction activities.
6.19 The Action and Limit levels for construction noise are defined in Table 6.1. Should non-compliance of the criteria occur, action in accordance with the Event and Action Plan in Table 6.2 shall be implemented.
Table 6.1 Action and Limit Levels for Construction Noise
|
Time Period |
Action Level |
Limit Level |
|
0700 –
1900 hours on normal weekdays |
When one documented compliant is received |
75 dB(A) |
Notes: If
works are to be carried out during restricted hours, the conditions stipulated in
the Construction Noise Permit (CNP) issued by the Noise Control Authority have
to be followed.
Construction Phase
6.20 The EIA report indicated that construction activities under both Phase 1 and Phase 2 would cause noise exceedance at representative NSRs. Therefore, appropriate mitigation measures and good site practices are recommended to be properly implemented. The mitigation measures recommended in the EIA report are summarised below:
·
Use of silenced types of PME, which
should be in accordance with BS 5228: Part 1, 1997 during construction
·
Implementation of the following good
site practices:
- Only well-maintained plant shall be operated on-site and plant shall be serviced regularly during the construction program.
- Silencers or mufflers on construction equipment shall be utilised and shall be properly maintained during the construction program.
- Mobile plant, if any, shall be sited as far away from NSRs as possible.
- Machines and plant (such as trucks) that may be in intermittent use shall be shut down between works periods or shall be throttled down to a minimum.
- Plant known to emit noise strongly in one direction shall, wherever possible, be orientated so that the noise is directed away from the nearby NSRs.
- Material stockpiles and other structures shall be effectively utilised, wherever practicable, in screening noise from on-site construction activities.
6.21 The implementation schedule for the recommended noise mitigation measures is presented in Appendix A.
Operation Phase
6.22 Based on the design information, most of the proposed equipment would be housed/enclosed in a concrete structure. In addition, acoustic louvers would be provided for fan rooms and general exhaust fans for plant rooms.
6.23 Noise barriers of 2.5m high have been proposed to surround the radiators. These barriers would be lined with sound absorbing material at the surface of the barrier facing the noise source to further enhance the noise reduction effectiveness.
6.24
Proper designs of the
crematorium would control the potential noise impact at noise sensitive
receivers within acceptable levels, thus operation phase noise monitoring would
be considered not necessary. Nevertheless, the ET shall carry out noise
measurements at
Staff Quarters of
6.25 The implementation schedule for the recommended noise mitigation measures is presented in Appendix A.
Table 6.2 Event/Action Plan for Construction Noise
|
Event |
Action |
|||
|
ET |
IEC |
ER |
Contractor |
|
|
Action
Level being exceeded |
1.
Notify ER, IEC and Contractor; 2.
Carry out investigation; 3.
Report the results of investigation to the IEC, ER and
Contractor; 4.
Discuss with the IEC and Contractor on remedial measures
required; 5.
Increase monitoring frequency to check mitigation
effectiveness. |
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. |
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. |
1. Submit
noise mitigation proposals to IEC and ER; 2. Implement
noise mitigation proposals. |
|
Limit
Level being exceeded |
1.
Inform IEC, ER, Contractor and EPD; 2.
Repeat measurements to confirm findings; 3.
Increase monitoring frequency; 4.
Identify source and investigate the cause of exceedance; 5.
Carry out analysis of Contractor’s working procedures; 6.
Discuss with the IEC, Contractor and ER on remedial
measures required; 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. |
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. |
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. |