3. NOISE

Construction Noise

3.1 As the noise sensitive receivers (NSRs) near the construction work area will be subjected to daytime, and possibly restricted-hour construction noise, a noise monitoring programme shall be developed by the ER to include daytime and restricted-hour (if necessary) noise measurement at the sensitive receivers. The programme shall be carried out by the ET to ensure that the noise level of construction works complies with the criteria of the Noise Control Ordinance (NCO) and other adopted noise criteria.

Noise Parameters

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

3.3 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 4 for reference.

Monitoring Equipment

3.4 As referred to in the Technical Memorandum (TM) issued under Noise Control Ordinance (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 1.0dB.

3.5 Noise measurements should not be made in the presence of 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.

3.6 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.

Monitoring Locations

3.7 The construction noise monitoring locations are shown in Figure 3.1 and Appendix 1 lists all NSRs identified in the EIA report. 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 ER and agreement from EPD of the proposal.

Table 3.1 Proposed Construction Noise Monitoring Stations

NSR.	Location
NMC1	CSD Married Staff Quarters
NMC2	Seamen’s Training Centre
NMC3	Customs & Excise Training School

3.8 When alternative monitoring locations are proposed, the monitoring locations should be chosen based on the following criteria:

a) At locations close to the major site activities which are likely to have noise impacts;

b) Close to the most affected existing noise sensitive receivers; and

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

3.9 The monitoring station shall normally be at a point 1 m from the exterior of the sensitive receivers 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 +3dB(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.

Baseline Monitoring

3.10 The ET shall carry out baseline noise monitoring within the four weeks 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 ER for approval before the monitoring starts.

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

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

Impact Monitoring

3.13 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 per week basis when noise generating activities are underway:

a) One set of measurements between 0700-1900 hours on normal weekdays;

b) One set of measurements between 1900-2300 hours;

c) One set of measurements between 2300-0700 hours of next day; and

d) One set of measurements between 0700-1900 hours on holidays, (or Sunday).

3.14 For the measurements (b), (c) and (d) above, one set of measurements shall at least include 3 consecutive Leq(5 min) results.

3.15 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.

3.16 In case of non-compliance with the construction noise criteria, more frequent monitoring as specified in the Action Plan in Section 3.17 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.

Event and Action Plan for Construction Noise

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

Table 3.2 Action/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)
0700-2300 hours on holidays; and 1900-2300 hours on all other days		60/65/70** dB(A)
2300-0700 hours of next day		45/50/55** dB(A)

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

** to be selected based on Area Sensitivity Rating

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.

Table 3.3 Event/Action Plan for Construction Noise

EVENT	ACTION
	ET	IC(E)	ER		CONTRACTOR
ACTION LEVEL
	1. Notify IC(E) and Contractor; 2. Carry out investigation 3. Report the results of investigation to the I(E) and Contractor; 4. Discuss with the Contractor and formulate remedial measures; and 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 problems; and 4. Ensure remedial measures are properly implemented	1. Submit noise mitigation proposals to IC(E). 2. Implement noise mitigation proposals.
LIMIT LEVEL
	1. Noise IE(E), 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 IC(E)< ER and EPD the causes & actions taken for the exceedances; 7. Assess effectiveness of Contractor’s remedial actions and keep IC(E)< EPD and ER informed of the results; and 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 E accordingly; and 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; and 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; and 5. Stop the relevant portion of works as determined by the ER until the exceedances is abated.

Construction Noise Mitigation Measures

3.18 The EIA report has recommended construction noise control and mitigation measures. The Contractor shall be responsible for the design and implementation of these measures.

Adoption of Quieter Plants

3.19 In order to reduce the excessive noise impacts at the affected NSRs, quieter plants (e.g. silenced PMEs) are recommended to be adopted in most of construction activities. The type of quiet PMEs adopted in this assessment is not a must that the Contractors have to use specific items of plant for the construction operations. The Contractors are allowed to use other type of quiet PMEs which has the same total sound power level, to suit their need.

Adoption of Movable Noise Barriers

3.20 The use of movable noise barriers were recommended in the EIA report for the following construction activities:

· Viaduct from Tai Lam Kok to Siu Lam : Piling, pile cap construction, bridge piers & abutment construction, casting of bridge beams and lifting of bridge beams.

· Siu Lam Interchange : relocation of CLP power sub-station, bored pile wall construction, road embankment, realignment of access road, roundabout modification, road pavement, utilities, footpath and road furniture.

3.21 The following construction activities were recommended to reduce the number of plant in operation during the examination period of the schools (Seamen’s Training Centre and Customs & Excise Training School):

· Road reconstruction from Tai Lam Kok to Siu Lam: road construction (excavation of existing pavement, road pavement, footpath and road furniture), utilities, fill slopes recompaction, cut slopes stabilization (soil nailing to cut slopes).

· Reclamation at Tai Lam Kok: dredging and sand filling.

3.22 Recheduling of the following concurrent construction activities to avoid simultaneous operating during the examination period of the schools:

Seamen’s Training Centre

· Piling works for viaduct from Tai Lam Kok to Siu Lam and dredging works at Tai Lam Kok

· Piling works for viaduct from Tai Lam Kok to Siu Lam and seawall construction at Tai Lam Kok

· Pile cap, bridge pier & abutment and filling works at Tai Lam Kok

· Fill slope recompaction and soil nailing to cut slopes (cut slopes stabilization) for road reconstruction from Tai Lam Kok to Siu Lam

Customs & Excise Training School

· Fill slopes recompaction and soil nailing to cut slopes (cut slopes stabilization) along the existing Castle Peak Road from Tai Lam Kok to Siu Lam

Good Site Practice

3.23 The following good site practice is recommended to implement during the construction phase of the project:

· 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.

· Machines 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, wherever possible, be orientated so that the noise is directed away from the nearby NSRs.

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

Operational Noise

3.24 As the NSRs close to the proposed Castle Peak Road will be exposed to traffic noise during the operational phase, a noise monitoring programme shall be developed to include noise measurements at NSRs during the peak traffic hour. The programme shall be carried out by the ET to ensure that the traffic noise levels are comparable to those predicted in the EIA under the full provision of the mitigation measures recommended.

Noise Parameters

3.25 The traffic noise level shall be measured twice within the first year of the road opening. Measurements shall be made in terms of the A-weighted L₁₀ over 3 half hour period during the peak traffic hour. A sample data record sheet is shown in Appendix 5 for reference.

Monitoring Equipment

3.26 As referred to in the Technical Memorandum on Noise From Construction Work other than Percussive Piling (GW-TW) issued under the Noise Control Ordinance (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 (A).

3.27 Noise measurements should not be made in the presence of 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.

3.28 The ET Leader is responsible for the provision and maintenance of the monitoring equipment. He shall ensure that sufficient noise measuring equipment and associated instrument 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.

Monitoring Locations

3.29 The operational noise monitoring locations are shown in Figure 3.2 and summarized in Table 3.4. The status and locations of noise sensitive receivers may change after issuing this manual. In such cases, the ET Leader shall propose updated monitoring locations and seek approval from ER, and agreement from the IC(E) and EPD of the proposal.

3.30 The alternative monitoring locations were selected according to the following criteria:

· They should be at NSRs in the vicinity of recommended direct technical remedies; preferably, there should be on representative monitoring locations near each type of noise screening element (i.e. vertical barrier, cantilever barrier and enclosure);

· One high floor and one medium floor monitoring points should be chosen at each location as far as possible; and

· Selected monitoring locations should enable monitoring to be done twice within one year after implementation of the mitigation measures during operation.

Table 3.4 Proposed Operation Noise Monitoring Stations

NSR	Location
NMO1	Block H of Correctional Services Department Married Staff Quarters
NMO2	Siu Lam Hospital
NMO3	Seamen’s Training Centre
NMO4	Block J of Correctional Services Department Married Staff Quarters

3.31 When alternative monitoring locations are proposed, the monitoring locations shall be chosen based on the following criteria:

· alternative location shall be similarly exposed to potential noise impacts;

· it shall be close to the noise sensitive receivers; and

· shall be located so as to cause minimal disturbance to the occupants.

· The operational noise monitoring shall be carried out at a distance of 1 m from the openable window and 1.2 m above the floor level of the noise sensitive receivers identified in Table 3.2. The ET Leader shall agree with the IC(E) on any necessary corrections adopted.

Baseline Monitoring

3.32 No baseline operational noise monitoring is required.

Noise Monitoring

3.33 Noise monitoring shall be carried out at all the designated traffic noise monitoring stations. The following is an initial guide on the traffic noise monitoring requirements during the operational phase:

· one set of measurements at the morning traffic peak hour on normal weekdays (exact timing to be confirmed with Transport Department and agreed with EPD);

· one set of measurements at the evening traffic peak hour on normal weekdays (exact timing to be confirmed with Transport Department and agreed with EPD);

· a concurrent census of traffic flow and percentage heavy vehicle shall be conducted for the road and the existing road network in the vicinity of each measuring point;

· average vehicle speed estimated; and

· the two sets of monitoring data should be obtained within the first year of operation.

3.34 Measured noise levels should be compared with predicted noise levels by applying appropriate conversion corrections to allow for the traffic conditions as the time of measurement. Appendix 5 shows a sample data record sheet for operational noise monitoring.

Event and Action Plan for Operation Noise

3.35 The Action levels for the operational phase traffic noise monitoring are shown in Table 3.5. Shall non-compliance of the criteria occurs, actions in accordance with the Event/Action Plan in Table 3.6, shall be carried out.

Table 3.5 Action Levels for Operational Noise

Sensitive Receiver	Action Level
Village Houses/other residential development	L10 equal to or higher than 70 dB(A)
Schools/educational establishments	L10 equal to or higher than 65 dB(A)

Table 3.6 Event/Action Plan for Operational Noise

EVENT	ACTION
	Monitoring Contractor	Highways Department
Action level is exceeded in any of the proposed monitoring stations	· Notify Highways Departments. Provide details of traffic flow and other monitoring condition to EPD. Notify Highways Department. Provide details of traffic flow and other monitoring condition to EPD	· Liaise with EPD to investigate noise mitigation proposals. · Implement noise mitigation proposals if required implement noise mitigation proposals if required.

Noise Mitigation Measures

3.36 The recommended noise mitigation measures in the EIA report are described below:

· A cantilevered barriers (5.5m high vertical barrier with a 5m cantilever at 45 degrees to the horizontal) of around 25m located behind the footpath of Castle Peak Road;

· A cantilevered barriers (5.5m high vertical barrier with a 3m cantilever at 45 degrees to the horizontal) of around 15m located at northbound carriageway of the slip road to the Siu Lam Interchange;

· A full enclosure of around 76 m at the slip road to the Siu Lam Interchange (CH102-CH178);

· A full enclosure of around 175 m at the Castle Peak Road viaduct (CH175-CH350);

· A cantilevered barriers (5.5m high vertical barrier with a 3m cantilever at 45 degrees to the horizontal) of around 604m located at eastbound carriageway of the Castle Peak Road viaduct (CH350 – CH954);