3. NOISE MONITORING

Monitoring Requirements

3.1 Noise monitoring was conducted at eight monitoring stations as specified in the EM&A Manual in the reporting month. Appendix B shows the baseline noise levels and established Action/Limit Levels for the environmental monitoring works.

Monitoring Equipment

3.2 Integrating Sound Level Meters used for noise monitoring. They were Type 1 sound level meters capable of giving a continuous readout of the noise level readings including equivalent continuous sound pressure level (L_eq) and percentile sound pressure level (L_x). They comply with International Electrotechnical Commission Publications 651:1979 (Type 1) and 804:1985 (Type 1). Also a portable electronic wind speed indicator capable of measuring wind speed in m/s was used to check wind speed. Table 3.1 below shows the noise monitoring equipment used.

Table 3.1 Noise Monitoring Equipment

Equipment	Model
Integrating Sound Level Meter	Rion Brand NL-31
Calibrator	Rion Brand NC-73

Monitoring Parameter, Frequency and Schedule

3.3 The monitoring schedule is shown in Appendix C. The frequency and parameters of noise measurement are presented in Table 3.2.

Table 3.2 Frequency and Parameters of Noise Monitoring

Time Period

Duration (min.)

Parameters

Frequency

Daytime

(07:00 to 19:00)

L_eq, L₉₀ & L₁₀

Once per week

Evening Time *

(19:00 to 23:00)

Three consecutive L_eq_(5min) per week

* Noise monitoring will be required only when there is construction work to conducted during the specified period

Monitoring Locations

3.4 In accordance with the EM&A Manual, ten designated monitoring stations as shown in Fig. 2.1 were selected for noise monitoring. An alternative location was selected for MN1 at Emmanuel Primary School with the consent from the ER and IC(E). Table 3.3 describes the locations of these monitoring stations.

Table 3.3 Location of the Noise Monitoring Stations

Station I. D.	Description	Sensitive Receiver in Vicinity	Type of Measurement
MN1	Emmanuel Primary School	SR19	Façade
MN2	Rhine Garden, Tower 1	SR20-1	Façade
MN3	Rhine Garden, Tower 5	SR20-3	Façade
MN4	Rhine Terrace	SR58	Façade
MN5	Golden Villa	SR21	Façade
MN6	Hoi Mei Beach House 1	SR22	Façade
MN7	Fung Loi	SR23	Façade
MN8	Vista Del Mar	SR24	Façade
MN9	Rivera Apartment	SR25	Façade
MN10	Ting Kau Villa	SR28	Façade

Monitoring Procedures

3.5 The field monitoring procedures were as follows:

· All measurement were installed in facade type, the microphone head of the sound level meter was positioned 1m exterior of the Noise Sensitive Receivers and lowered sufficiently so that the building’s external wall acts as a reflecting surface.

· The battery condition was checked to ensure good functioning of the meter.

· Parameters such as frequency weighting, the time weighting and the measurement time were set as follows:

- frequency weighting : A

- time weighting : Fast

- time measurement : 30 minutes

· Prior to and after each noise measurement, the meter was calibrated using the Calibrator for 94 dB at 1000 Hz. If the difference in the calibration level before and after measurement was more than 1 dB (A), the measurement would be considered invalid and repeat of noise measurement would be required after re-calibration or repair of the equipment.

· The wind speed was frequently checked with the portable wind meter.

· At the end of the monitoring, the Leq, L10 and L90 were recorded. In addition, site conditions and noise sources were recorded on a standard record sheet.

· Noise measurement would be paused during periods of high intrusive noise and observation would be recorded when intrusive noise could not be avoided.

· Noise monitoring would be cancelled in the presence of fog, rain, and wind with a steady speed exceeding 5 m/s, or wind with gusts exceeding 10 m/s.

3.6 Regular equipment maintenance and calibration was performed as follows:

· The microphone head of the sound level meter and calibrator would be cleaned with a soft cloth at quarterly intervals.

· The meter would be sent to the supplier to check and calibrate at yearly intervals.

3.7 Calibrations certificates for the equipment employed are presented in Appendix D.

Results and Observations

3.8 Noise monitoring was conducted at the 8 designated monitoring stations (MN1-5 & 8-10) during 07:00 – 19:00 as scheduled in the month. Regarding two noise monitoring stations (MN6 & 7), the monitoring events had been suspended since 21 July 2003 as agreed with ER, IC(E) and EPD. A summary of all the noise monitoring results is presented in Table 3.4. Noise monitoring results and graphical presentations are provided in Appendix F.

Table 3.4 Summary of Impact Noise Levels during 07:00 – 19:00

0700 – 1900 on normal weekdays	Noise Level, dB(A) L_eq _{(30 min)}
0700 – 1900 on normal weekdays	Range	Limit Level
MN1	63.6 – 66.7	70
MN2	63.8 – 66.4	75
MN3	65.5 – 67.2	75
MN4	63.1 – 64.2	75
MN5	64.4 – 65.0	75
MN8	63.8 – 65.3	75
MN9	66.0 – 67.5	75
MN10	66.2 – 67.3	75

3.9 The major noise sources were road paving activities near Ting Kau Village, Ting Kau Carpark, BPRW100, Slope 15, E01W/E02E, RW22, Slope 13 and Sham Tseng. All the monitoring results were below the limit level at the nearest monitoring station in the reporting month, the Contractor has implemented all the necessary mitigation measures, which included the scheduling of noisy construction activities to commence later in the morning in order to minimize the noise impact.

3.10 Major noise sources also included construction activities of other nearby sites, traffic along Castle Peak Road and Tuen Mun Road and community noise mainly at Sham Tseng Area.