2                     NOISE IMAPCT

2.1               Introduction

2.1.1          In this section, the requirements, methodology, equipment, monitoring locations, criteria and protocols for the monitoring and audit of air quality impact during the construction phase and operation phase of the Project are presented.

2.1.2          Construction noise impacts and traffic noise impact from this Project are predicted at the identified NSRs.  Noise mitigation measures would be required to reduce noise levels to the stipulated standard.  A noise monitoring programme shall be undertaken to ensure such mitigation measures would be implemented properly.

2.1.3          According to the EIA, road traffic noise levels should be monitored at representative NSRs, which are in the vicinity of the recommended direct mitigation measures, during the first year after road opening. The purpose of the monitoring is to ascertain that the noise levels would comply with the noise criteria at the sensitive receivers, and that the recommended mitigation measures are effective in suppressing the noise levels.

2.2               Noise Parameters

2.2.1          The construction noise levels 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.

2.2.2          The ET Leader shall also carry out monitoring of road traffic noise after the works under Contract are completed and put into operation.  The road traffic noise during operation of the Project shall be measured in terms of the A-weighted equivalent of L10 (1-hr).  During the traffic noise measurement, traffic count shall also be undertaken concurrently.

2.2.3          As supplementary information for data auditing, statistical results such as L10 and L90 shall also be obtained for reference.  Sample noise field data sheets are shown in Appendices C and D to this Manual 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.

2.3               Monitoring Requirement and Equipment

2.3.1          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 shall be accepted as valid only if the calibration levels before and after the noise measurement agreed to within 1.0 dB.

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

2.3.3          The ET is responsible for providing sufficient and suitable noise measuring equipment and associated instrumentation for carrying out the baseline monitoring, regular impact monitoring and ad hoc monitoring.  All the equipment and associated instrumentation shall be clearly labeled.

 

2.4               Monitoring Locations for Construction Phase

2.4.1          The locations of construction noise monitoring stations are summarized in Table 2.1 and shown in Figures 2.1A – 2.1C. These locations represent the worst affected sensitive receiver during unmitigated construction activities.

Table 2.1          Noise Monitoring Stations during Construction Phase

Identification No.

Construction Noise Monitoring Location

FEC

Far East Consortium Tuen Mun Central Building

TMTP1

Tuen Mun Town Plaza

WG2

Waldorf Garden

CLFY1

Chi Lok Fa Yuen

TTP

Tung Wah Group of Hospitals Tai Tung Pui Social Service Building

KFG3D

Kam Fai Garden

 

2.4.2          The status and location 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.

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

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

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

§         Assurance of minimal disturbance to the occupants during monitoring.

 

2.4.4          The monitoring station shall normally be at a point 1 m from the exterior of the noise sensitive facade and be at a position 1.2 m above ground.  If there is a problem with access to the normal monitoring position, an alternative position shall 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.

2.5               Baseline Monitoring for Construction Noise

2.5.1          Baseline noise monitoring shall be carried out 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 ensure accuracy of the baseline monitoring results.

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

2.5.3          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.

2.6               Impact Monitoring for Construction Noise

2.6.1          Noise monitoring shall be carried out at 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 on a weekly basis when noise generating activities are underway:

§         One set of measurement between 0700 and 1900 hours on normal weekdays.

2.6.2          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.

2.6.3          If a school exists near the construction activity, noise monitoring shall be carried out at the monitoring stations for the school 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.

2.6.4          In case of non-compliance with the construction noise criteria, more frequent monitoring, as specified in the Action Plan in Table 2.5, 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.

2.6.5          A schedule on the compliance monitoring shall be submitted to the ER and IEC for approval before the monitoring starts.

 

 

 

2.7               Event and Action Plan

Construction Phase

2.7.1          The Action and Limit levels for construction noise are defined in Table 2.2.  Should non-compliance of the criteria occur, action in accordance with the Event and Action Plan in Table 2.5 shall be implemented.

Table 2.2          Action and Limit Levels for Construction Noise

Time Period

Action Level

Limit Level*

0700-1900 hours on normal weekday

When one documented complaint is received

70/65# (school)

75 (others)

Note:        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.

# For normal daytime working hours, the noise criteria are 70 dB(A) and 65 dB(A) for normal teaching periods and examination periods, respectively.

* If baseline noise monitoring data exceed the statutory criteria, the Limit Level would be based on the baseline noise levels.

 

2.8               Construction Noise Mitigation Measures

2.8.1          Good site practice and noise management can significantly reduce the impact of construction site activities on nearby NSRs.  The following package of measures should be followed during  construction:

§         Only well-maintained plant should be operated on-site and plant should be serviced regularly during the construction works;

§         Machines and plant 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 to direct noise away from the NSRs;

§         Mobile plant should be sited as far away from NSRs as possible; and

§         Material stockpiles and other structures should be effectively utilized, where practicable, to screen noise from on-site construction activities.

2.8.2          Mitigation measures are proposed to be implemented in three levels, namely Level 1, which involves adoption of quiet PME; Level 2, which involves provision of movable noise barrier; and Level 3, which involves scheduling of construction activities.

Level 1 – Adoption of Quiet PME

2.8.3          Quieter PME to be used in the assessment are given in Table 2.3.

Table 2.3          Listing of Quiet PME Items

Quiet Powered Mechanical Equipment (PME)

Identification Code / BS5228

Maximum SWL, dB(A)

Excavator

C8/33

102

Crane

C7/114

101

Truck

C3/59

105

Concrete Truck

C6/35

100

Poker Vibrator

CNP 173

102

Asphalt Paver

C8/24

101

Roller, vibratory

C3/115

102

 

Level 2 – Use of Movable Noise Barrier

2.8.4          Use of movable noise barrier (3m high or above) is proposed to be provided for the PMEs operated in the vicinity of the NSRs given in Table 2.4 during the construction phase.

Table 2.4          NSRs – with Movable Noise Barrier


NSR

Description

FEC

Far East Consortium Tuen Mun Central Building

FM

Forward Mansion

HTB

Hing Tai Building

TMTP1

Tuen Mun Town Plaza

WG2

Waldorf Garden

CMA*

CMA Choi Cheung Kok Secondary School

LWF*

Yan Oi Tong Madam Lau Wong Fat Primary School

TMF

Tuen Mun Fa Yuen

LCK*

Lui Cheung Kwong Lutheran College

CLFY1

Chi Lok Fa Yuen

TFH

On Ting Estate ( Ting Fuk House)

LCKP*

Lui Cheung Kwong Lutheran Primary School

TTP

Tung Wah Group of Hospitals Tai Tung Pui Social Service Building

CSBS*

CSBS Mrs. Aw Boon Haw Secondary School

KFG3D

Kam Fai Garden

Remark:

NSR with asterisk means educational institution.

Level 3 – Scheduling of Construction Activities

2.8.5          It is proposed that site clearance and the following activities not to be undertaken in the vicinity of the NSR LCK at stage 2 (Ch. 28050 – 28200 of TMR) so as to reduce construction noise impact during normal teaching hours.

·             Truck would not operate concurrently with other PMEs during tree transplanting and noise barrier foundation work.

·             Tree Transplanting would not be undertaken concurrently with Bulk Excavation and Utilities Diversion.

·             Construction of Storm Water Drain would not be undertaken concurrently with Noise Barrier/Enclosure Foundation.

·             Construction of Sub-base and Road Base would not be undertaken concurrently with Noise Barrier/Enclosure Installation.

·             Road Surfacing, Construction of Road kerbs, Central Dividers, Parapets, and Installation of Crash Cushion and Sign Gantry would not be undertaken concurrently.

·             Installation of Gantry and Directional Lighting, and Street Lighting would not be undertaken concurrently.

2.8.6          In order to avoid or reduce the construction noise problems at the schools during examination, the Contractor of the Project is suggested to liaison with all the relevant schools (CMA, LWF, LCK, LCKP and CSBS) to check out their examination periods and activities at the beginning of the work programme.  Thus, the Contractor can make good planning and arrangement of works and provide sufficient mitigation plans to alleviate the noise impacts.

Table 2.5          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 ET 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 ET 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.

2.9               Operational Traffic Noise Monitoring

2.9.1          The ET shall prepare and deposit to EPD, at least 6 months before the operation of the works under the Project, a monitoring plan for the purpose of assessing the accuracy of traffic noise predictions by comparing the project noise impact predictions with the actual impacts.  The monitoring plan shall contain monitoring locations, monitoring schedules, methodology of noise monitoring including noise measurement procedures, traffic counts and speed checks, and methodology of comparison with the predicted levels.  The ET shall implement the monitoring plan in accordance with the deposited monitoring plan unless with prior justification.  Monitoring details and results including the comparison between the measured noise levels and the predicted levels shall be recorded in a report to be deposited with EPD within one month of the completion of the monitoring.  The report shall be certified by the ET Leader and the Project Proponent before deposit with EPD.

2.9.2          The traffic noise levels shall be measured twice at 6-month intervals within the first year upon completion of the Project.  Measurements shall be made in terms of the A-weighted L10 over 3 half hour periods during the peak traffic hour, other metrics like Leq may be added as seen fit.

2.9.3          As shown in Table 2.6, nine designated monitoring stations are selected for operational noise monitoring.  Figures 2.2A – 2.2C describes the operational noise monitoring locations, which are also depicted in.  The status and locations of noise sensitive receivers may change after this Manual is issued.  If such cases exist, the ET Leader shall propose updated monitoring locations and seek approval from the ER and IEC and agreement from EPD of the proposal.

Table 2.6          Noise Monitoring Stations during Operation Phase

Identification No.

Operational Traffic Noise Monitoring Location

SC

Sun Court

TMTP4

Tuen Mun Town Plaza

TMTP2

Tuen Mun Town Plaza

NTM1

New Town Mansion

TMF

Tuen Mun Fa Yuen

LCK

Lui Cheung Kwong Lutheran College

CLFY1

Chi Lok Fa Yuen

HKG

Hong King Garden

KFG3A

Kam Fai Garden

 

2.9.4          The monitoring locations shall be selected according to the following criteria:

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

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

§         Selected monitoring locations shall enable monitoring to be done twice within one year after implementation of the mitigation measures during operation of the proposed road.

2.9.5          The status and location 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.

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

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

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

§         Assurance of minimal disturbance to the occupants during monitoring.

2.9.7          The operational noise monitoring shall be carried out a distance 1m from the operable window and 1.2m above the floor level of the noise sensitive receivers identified. The ET shall agree with the IEC on any necessary corrections adopted.

2.9.8          Traffic 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;

§         One set of measurement at the evening traffic peak hour on normal weekdays;

§         A concurrent census of traffic flow and percentage heavy vehicles shall be conducted for the far-side and near-side of the road and the existing road network in the vicinity of each measurement points;

§         Average vehicle speed estimated for far-side and near-side of the road and the existing road network in the vicinity of each measuring points; and

§         The two sets of monitoring data shall be obtained within the first year of operation.

2.9.9          Measured noise levels shall be compared with the predicted noise levels by applying appropriate conversion corrections to allow for the traffic conditions at the time of measurement.  A sample data record sheet for traffic noise monitoring is shown in
Appendix C.

2.9.10      The measured/ monitored noise levels shall be compared with the predicted results and the predicted traffic flow conditions (calculated noise levels based on concurrent traffic census obtained). In case discrepancies are observed, explanation shall be given to justify the discrepancies.