2.                   noise MONITORING


2.1               In this section, the EM&A requirements during construction phase and operation phase are presented.  As insignificant construction noise impacts would be anticipated, no monitoring was considered necessary.  However, environmental audit was recommended so as to monitor the implementation of good site practices during construction. The recommended mitigation measures during the construction phase are presented in this section. The audit requirement is addressed in Section 6.

2.2               The predicted helicopter noise levels from the proposed helipad would comply with relevant criteria.  It was recommended to conduct noise monitoring after the commencement of operation of the proposed new helipad.  Real-time reporting of monitoring data through a dedicated internet website is required.  The methodology, equipment, monitoring locations, criteria and protocols for the monitoring and audit of noise impacts during the operation phase of the Project are presented below.

Noise Parameters

2.3               The helicopter noise level due to the proposed new helipad shall be measured in terms of the maximum sound pressure level (Lmax) as the monitoring parameter for the time period between 0700 and 1900 hours on any days comparing with the criteria stipulated in the EIAO-TM.  For the time period between 1900 and 2300 hours, A-weighted equivalent continuous sound pressure level Leq (4 hours) shall be employed for comparison with the proposed noise criteria in the EIA Report, 65 dB(A).

2.4               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 B for reference.  The background noise levels at the measurement points during the absence of helicopter flight at MFT Building shall also be recorded.

Monitoring Equipment

2.5               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 should be accepted as valid only if the calibration level from before and after the noise measurement agrees to within 1.0 dB. 

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

2.7               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 regular impact monitoring and ad hoc monitoring.  All the equipment and associated instrumentation shall be clearly labelled.

Monitoring Locations

2.8               Based on the EIA Report, three worst affected locations are designated for helicopter noise monitoring as listed in Table 2.1 and illustrated in Figure 2.1.  The status and location of noise sensitive receivers may change after issuing this manual.  If such cases exist, the ET Leader shall propose updated monitoring locations and seek approval from CAD and agreement from the IC(E) and EPD on the proposal.

Table 2.1          Noise Monitoring Stations during Operation Phase

Identification No.

Noise Monitoring Location


The Bauhinia (Korea Centre)


Ka On Building


Talon Tower

2.9               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;

·         Assurance of minimal disturbance to the occupants during monitoring.

2.10            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 should 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.

Impact Monitoring for Helicopter Noise

2.11            Noise monitoring shall be carried out at all the designated monitoring stations.  The regular monitoring frequency for each station would be on a monthly basis during the first year of operation of the proposed new helipad at MFT Building, then for the following four years operation, monitoring frequency for each station would be on a quarterly basis, after that, half yearly basis monitoring would be conducted at the sixth year.  The monitoring frequency would be reviewed in light of monitoring data or in case of any change in helicopter types and flight frequency.  The details of monitoring are as follows:

·         one set of measurements for a flight event (including Approach, Hovering, Idling and Take Off) between 0700 and 1900 hours on normal weekdays; and

·         one set of measurement of Leq(4hrs) during 1900 and 2300 hours on normal weekdays.

2.12            In addition, site conditions and other noise sources shall be recorded during the monitoring period.

2.13            In case of non-compliance with the helicopter noise criteria, more frequent monitoring, as specified in the Action Plan in Table 2.3, shall be carried out.  This additional monitoring shall be continued until the recorded noise levels are rectified or proved to be irrelevant to the helicopter operation at the proposed new helipad.

2.14            All monitoring data shall be reported and uploaded to the internet website in an agreed format with EPD and CAD for public inspection once completion of helicopter noise measurement.


Event and Action Plan

Helicopter Noise

2.15            Baseline conditions were made in accordance to the existing allowable condition.  Based on the allowable flight condition, the predicted noise levels at representative receivers range from Leq(4 hrs) 64 to 69 dB(A) while the maximum noise level Lmax 86 dB(A) is predicted.    For the future operation,  the cumulative noise levels arising from operation on both existing helipad and proposed new helipad would not increase the existing noise level by more than 1.0 dB(A), with the condition that the operator strictly follow to the flight schedule as stated in the EIA report.  Appendix D shows the details of the future flight operation schedule.  

2.16            ET will be responsible for auditing of flight schedule and noise monitoring against the baseline condition.    

2.17            The Action and Limit levels for helicopter noise from the proposed new helipad are defined in Table 2.2.  Should non-compliance of the criteria occur, action in accordance with the Action Plan in Table 2.3 shall be carried out.

Table 2.2          Action and Limit Levels for Helicopter Noise

Time Period

Action Level

Limit Level

0700 – 1900 hours

When one documented complaint is received

Lmax 85 dB(A) for residential dwellings



1900 – 2300 hours

When one documented complaint is received

(i) Leq (4hrs) 65 dB(A) for residential dwellings &


(ii) Compliance with flight schedule as stated in Appendix DNon-compliance would be recorded for the operation violate both conditions


Table   2.3        Event / Action Plan for Helicopter Noise







Heliport / Helicopter Operator

Action Level

1.       Notify IC(E), CAD and Heliport / Helicopter Operator;

2.       Carry out investigation;

3.       Report the results of investigation to the IC(E), CAD and the Heliport / Helicopter Operator;

4.       Discuss with the Heliport / Helicopter Operator 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 Heliport / Helicopter Operator 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 Heliport / Helicopter Operator  to propose remedial measures for the analysed noise problem;

4.       Ensure remedial measures are properly implemented.


1.  Submit noise mitigation proposals to IC(E) & CAD;

2.  Implement noise mitigation proposals.

Limit Level

1.       Identify source;

2.       Inform IC(E), CAD, EPD and Heliport / Helicopter Operator;

3.       Repeat measurements to confirm findings;

4.       Increase monitoring frequency;

5.       Carry out analysis of Helicopter Operator’s working procedures to determine possible mitigation to be implemented;

6.       Inform IC(E), CAD and EPD the causes and actions taken for the exceedances;

7.       Assess effectiveness of Helicopter Operator’s remedial actions and keep IC(E), EPD and CAD informed of the results;

8.       If exceedance stops, cease additional monitoring.

1.       Discuss amongst CAD, ET, and Heliport / Helicopter Operator on the potential remedial actions;

2.       Review Heliport / Helicopter Operator remedial actions whenever necessary to assure their effectiveness and advise the CAD accordingly;

3.       Supervise the implementation of remedial measures.

1.       Confirm receipt of notification of failure in writing;

2.       Notify Heliport / Helicopter Operator;

3.       Require Heliport / Helicopter Operator 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 Heliport / Helicopter Operator to reduce/stop the helicopter flights operated at the proposed helipad 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.       Reduce/Stop the helicopter flights operated at the proposed helipad as determined by the CAD until the exceedance is abated.

Mitigation Measures


Construction Phase


2.18            As detailed in the EIA Report for the Project, the following good site practices are recommended:

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

·         Silencers or mufflers on construction equipment should be utilised and should be properly maintained during the construction programme;

·         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.


Operation Phase


2.19            The use of helicopter S92 or the helicopters with noise emissions exceeding those from helicopter S76C+ is not recommended for proposed helipad.  In view of cumulative noise impacts, the maximum allowable flight movement for both existing helipad and proposed helipad during 1900 – 2300 hours would be limited such that the predicted operation noise levels at all closest representative NSRs would not increase the existing noise levels (i.e. without the Project) by 1.0 dB(A).  The residual impact is considered acceptable.