5                                            Noise

5.1                                      Introduction

This Section presents the potential noise impacts associated with the site levelling, track paving and the noise impacts associated with maintenance and operation of the Project.

5.2                                      Relevant Legislation and Guidelines

5.2.1                                Construction Noise

The principal legislation relating to the control of construction noise is the Noise Control Ordinance (Cap. 400) (NCO).  Various Technical Memoranda (TMs), which stipulate control approaches and criteria, have been issued under the NCO.  The following TMs are applicable to the control of noise from construction activities:

·       Technical Memorandum on Noise from Construction Work other than Percussive Piling (GW-TM); and

·       Technical Memorandum on Noise from Construction Work in Designated Areas (DA-TM).

Apart from the above, the Environmental Impact Assessment Ordinance (EIAO) (Cap. 499) also provides means to assess construction noise impacts.  The Technical Memorandum on Environmental Impact Assessment Process (EIAO-TM), issued under the EIAO, provides guidelines and noise criteria for evaluating construction noise impacts.

General Construction Works

Under the EIAO, noise impact arising from general construction works during normal working hours (i.e. 0700 to 1900 hours on any day not being a Sunday or public holiday) at the openable windows of buildings is to be assessed in accordance with the noise criteria as given in the EIAO-TM.  The EIAO-TM noise standards are presented in Table 5.1.

Table 5.1        EIAO-TM Daytime Construction Noise Standard (Leq, 30 min dB(A))

Use

Noise Standard

Domestic Premises

75

Educational Institutions (normal periods)

Educational Institutions (during examination periods)

70

65

When assessing a CNP application for the use of Powered Mechanical Equipment (PME) during restricted hours, the Noise Control Authority will compare the ANLs, as promulgated in GW-TM, and the CNLs (after accounting for factors such as barrier effects and reflections) associated with the proposed PME operations.  The ANLs are related to the noise sensitivity of the area in question and different Area Sensitivity Ratings have been established to reflect the background characteristics of different areas.  The relevant ANLs are shown in Table 5.2.

The Noise Control Authority will consider a well-justified Construction Noise Permit (CNP) application, once filed, for construction works within restricted hours as guided by the relevant Technical Memorandum issued under the NCO.  The Noise Control Authority will take into account adjoining land uses and any previous complaints against construction activities at the site before making a decision in granting a CNP.  Nothing in this EIA Report shall bind the Noise Control Authority in making his decision.  The Noise Control Authority may include any conditions in a CNP that it considers appropriate.  Failure to comply with any such conditions may lead to cancellation of the CNP and prosecution action under the NCO.

Table 5.2        Acceptable Noise Levels (ANL, Leq, 5 min dB(A))

Time period

Area Sensitivity Rating

 

A

B

C

All days during the evening (1900-2300 hours) and general holidays (including Sundays) during the day and evening (0700-2300 hours)

60

65

70

All days during the night-time (2300-0700 hours)

45

50

55

In addition to the general controls on the use of PME during restricted hours, the EPD has implemented a more stringent scheme via the DA-TM.  The DA-TM regulates the use of five types of Specified Powered Mechanical Equipment (SPME) and three types of Prescribed Construction Work (PCW), which are non-PME activities, in primarily densely populated neighbourhoods called Designated Areas (DAs).  The SPME and PCW are:

SPME:

·         hand-held breaker;

·         bulldozer;

·         concrete lorry mixer;

·         dump truck; and

·         hand-held vibratory poker.

PCW:

·         erection or dismantling of formwork or scaffolding;

·         loading, unloading or handling of rubble, wooden boards, steel bars, wood or scaffolding material; and

·         hammering.

A CNP will be required for works during the time between 1900 and 0700 hours and any time on a general holiday, including Sunday, and the noise criteria for evaluating noise impact laid down in relevant TM issued under the NCO must be met.

As the Study Area is located outside a designated area, the noise criteria stipulated under the DA-TM are not applicable in this Study.

5.2.2                                Operational Noise

The EIAO-TM and Technical Memorandum on Noise From Places Other than Domestic Premises, Public Places or Construction Sites (IND-TM) specifies the applicable Acceptable Noise Levels (ANLs) for operational noise of the karting track.  The ANLs are dependent on the Area Sensitivity Rating (ASR) and the time of the day and are presented in Table 5.3.

Table 5.3        ANLs to be used as Operation Noise Criteria

Time Period

LAeq 30min (dB(A))

ASR “A”

ASR “B”

ASR “C”

Daytime 0700-1900

60

65

70

Evening 1900-2300

60

65

70

Night-time 2300-0700

50

55

60

Fixed Plant Noise

Fixed plant noise is controlled under Section 13 of the NCO and the predictions will be undertaken in accordance with the IND-TM.  The criteria noise limits are set out in the EIAO-TM as follows:

·       the total fixed source noise level at the facade of the nearest NSR is at least 5 dB(A) lower than the appropriate ANL (as shown in Table 5.3) as specified in the Technical Memorandum on Noise from Places other than Domestic Premises, Public Places or Construction Sites (IND-TM);  or,

·       where the prevailing noise level in the area is 5 dB(A) or more below the appropriate ANL, the total fixed source noise level must not exceed this noise level. 

The criteria noise limits stipulated in the IND-TM are dependent on the Area Sensitivity Rating (ASR) of the NSRs as shown in Table 5.3.

In any event, the Area Sensitive Rating assumed in this Report is for indicative assessment only given that there are currently no influencing factors assumed in the vicinity of the NSRs.  It should be noted that fixed noise sources are controlled under Section 13 of the NCO.  At the time of investigation, the Noise Control Authority shall determine noise impact from concerned fixed noise sources on the basis of prevailing legislation and practices being in force, and taking account of contemporary conditions / situations of adjoining land uses.  Nothing in this Report shall bind the Noise Control Authority in the context of law enforcement against all the fixed noise sources being assessed in this report.

5.3                                      Baseline Environmental Conditions and Noise Sensitive Receivers

5.3.1                                Baseline Environmental Conditions

The proposed karting track is located at Lung Kwu Sheung Tan which is rural in nature and is characterised predominantly industrial uses.  The existing land uses to the west of the site are open storage of powered mechanical equipment, plastics recycling factories, concrete batching plant and dangerous goods stores.  The site is currently approximately 5 mPD, which is lower than the level of Lung Kwu Tan Road.  A Tsz Tong (Lau’s ancestral hall) and a village house are located within the site area. 

Background noise is dominated by the traffic noise from Lung Kwu Tan Road and the loading and unloading activities undertaken in the plastics recycling factory and the traffic movement within the area located to the west of the site.  

5.3.2                                Noise Sensitive Receivers

As discussed in Section 5.3.1, the proposed site included an existing village house and a Tsz Tong.  The Tsz Tong will be kept without any modification and will only be used by the Lau’s family members of Lung Kwu Tan village for private functions and unauthorized public entry is strictly prohibited, and therefore Tsz Tong is not considered as a public place of worship.  In view that the Tsz Tong will not be used by any public at any time, for the purpose of this EIA, the Tsz Tong has not been identified as a NSR.

Agreement has been made between the land owner and the Project Proponent that the proposed site (including the village house to be used as an office) will be leased to the Project Proponent for the development of an outdoor karting track.  The village house within the site boundary will be used as an office for the karting track only.  Residential use is not permitted at the village house while the land is used as an outdoor karting track.  The Project Proponent also confirmed that the village house will only be used as an office of the karting track.  In view that the village house will not be used as residential purpose during the karting track leasing period, for the purpose of this EIA, the village house has not been identified as a NSR.  However, should this village house is to be used for residential purpose during the operation of the karting track, mitigation measures are proposed in order to attenuate the noise impact (see Annex B).          

A land search has been conducted to identify any existing NSRs within 300 m from the Study Area boundary.  Three ruined and vacant building structures were observed to be located to the west of site during the search.  During a site visit, it has been identified that these structures have been converted as a canteen and located within the industrial area and therefore these village houses have not been identified as a NSR.  However, should these building structures are used for residential purpose, in view of the large separation distance, noise impacts associated with the karting track is not expected.

In addition, as confirmed with the District Lands Office (DLO), there are no planned residential uses identified within the Study Area.

It has been identified during site visit that the industrial area located to the west of the Site are used for open storage, plastics recycling factories and canteens for the workers in the vicinity. 

The nearest residential uses have been identified as the village house at Pak Long located at about 1153m from the southern site boundary.  The locations of the identified NSRs are shown in Figure 5.1.  No planned NSRs are identified in the study boundary. 

A noise survey was conducted in 22nd July 2005 to investigate the existing acoustic condition at the identified NSRs.  The background in Pak Long was dominated by the road traffic noise from Lung Kwu Tan Road, and the measured daytime noise level Leq, 15min at the NSR was 54.9 dB(A). 

As the site is located in a rural area and no influencing factors affect the NSRs, an ASR “A” has been assumed for the NSRs located at Pak Long.  As the measured prevailing noise level was lower than the (ANL-5) criterion, and therefore the criterion, i.e. 54.9 dB(A) LAeq, 30min for daytime period will be considered as the stipulated noise limit for the assessment of operational noise impact. 

Table 5.4        Identified Noise Sensitive Receivers

NSR

Location

Type of Uses

 

N1

No. 32 Pak Long

Residential (3-Storey)

 

5.4                                      Potential Sources of Impact

5.4.1                                Construction Phase

The major construction activities associated with the Project that may cause noise impacts to the NSRs are:

·       Excavation and compaction works for forming levelled ground; and

·       Track Paving.

The construction period of the Project will take approximate 2 months.  In addition, the construction works for site leveling and track paving will be carried out in phases without overlapping according to planned project programme, i.e. track paving will be carried out after completion of Site Formation.

The use of PME during the construction phase will be the main source of noise impact.  The use of PMEs such as bulldozer, excavator, dump truck, asphalt paver and road roller will be involved in the construction activities. 

Annex A presents a detailed list of PMEs, which are provided by the Project Proponent, assumed for each construction activity considered in the noise impact assessment.  Project Proponent has confirmed that the plant inventory is practicable for the construction of karting track. 

The normal working hours of the contractor will be between 07:00 and 19:00 hours from Monday to Saturday (except public holidays) and construction activities during restricted hours are not expected.  Should evening and night works between 19:00 and 07:00 hours or on public holidays (including Sunday) be required, the contractor should submit a CNP application and will be assessed by the Noise Control Authority.  Conditions stipulated in CNPs should be strictly followed.

5.4.2                                Operational Phase

The design of the karting track will meet international standard for kart racing and safety standard, and will only serve members of the Hong Kong Kart Club for sporting purposes.  In addition, the proposed karting track will be used for training or local racing events.  It should be iterated that there will be no international events to be carried out at the proposed track. 

The karts to be running on the track are powered by Rotax Max FR125 2-stroke single cylinder engines with displacement of 125c.c.  As given in the technical specification of the kart, the exhaust system is provided with intake silencer for reduction of noise from exhaust system.  The major noise sources during the operational phase are therefore identified as kart movement and public address (PA). 

The karting track will operated from Monday to Sunday with operating hours from 09:30 to 19:00 hours.  The maximum number of karts to be allowed to run on the track is 40 at any time.  In addition, for a conservative assessment, each run with up to 40 karts on the track is assumed to last for a full 30 minutes during any half hour.  Project Proponent has also confirmed to maintain a maximum number of 200 visitors on site at any time.  To control the number of visitors and traffic generation, a 45-person bus would run every hour between Tuen Mun Town Centre and the karting track for transportation of the guest and participants, and there will be around 10 bus trips per day.  In addition, no on-site parking facility/area will be provided at the proposed karting track for minimizing traffic generation and there are no parking facility /area located in the vicinity of the proposed site, it is anticipated that small number of visitors may drive to the site.  In view of the small number of traffic induced on the existing road traffic, it is anticipated that induced traffic noise would not pose adverse impact to the NSRs in Lung Kwu Sheung Tan.

Only minor maintenance works will be carried out within the site so as to ensure the karts operate properly.  In addition, only external repair will be undertaken at site (ie replacement of bodywork).  Any engine maintenance work will not be carried on site.  If such works are required, the vehicle will be transport to a garage for such repair. 

The PA system at the karting track will be similar to the PA system at Kartodromo de Coloane, however the project size of karting track is smaller than Kartodromo de Coloane, and therefore the power and number of speakers at the karting track will be smaller that at Kartodromo de Coloane.  It is assumed that a total of 5 sets of PA system (each with 2 speakers) will be provided within karting track.   

Noise Emission from Karts and PA System

Noise measurement has been conducted for a kart racing on 27 November 2005 in the Kartodromo de Coloane at Macau, to obtain noise emission data of similar karting track operation.  The kart race was participated by 13 karts which are powered by the same engine (ie Rotax Max FR125 2-stroke single cylinder engines with displacement of 125 c.c) to be used in the Project.  The noise measurement is therefore considered to be representative of the proposed karting track operation.

Broadband measurement of LAeq, L10, L90, Lmax and Lmin has been recorded at 500ms interval to capture the noise emissions from karts moving in high speed in front of sound level meter.  At least 5 minutes measurement was conducted at different locations along the track in order to collect noise data from different kart movements inclusion of tyre noise, skidding noise and braking noise.  To allow a conservative assessment, the highest Leq,5 min among different kart movements has been taken to predict the sound pressure level at the identified NSRs.  A summary of the noise measurement results is presented in Table 5.5.  Annex B presents the Leq, 500ms time history measured at the different measurement locations.

As PA system at the karting track will be similar to the PA system at Kartodromo de Coloane, noise measurement was also conducted for the PA system during announcement period only and the measured Leq, 8 sec at 3m from the PA system (with two speakers) is 86.2 dB(A).  The sound power level of the PA system is 104 dB(A).  The PA system was used occasionally and it is assumed that the PA system will be used 5 minutes in every 30 minutes.

Table 5.5        Summary of Noise Measurement for Kart Track Operation

Source

Distance from source, m

Leq, 5 min(1)(2),  dB(A)

Calculated Leq, 5 min at   1 meter , dB(A)

Remarks

 

Kart Movement (13 karts running at high speed)

3

85.2

94.7

Measurement taken in front of a straight section of the track

 

 

2.5

82.6

90.6

Measurement taken in front of a 90° turning section

 

 

5

84.2

98.2

Measurement taken in front of a 120° turning section

 

 

4

85.1

97.1

Measurement taken in front of a 180° turning section

 

Remarks:

1) Noise measurement was conducted with reference to the calibration and measurement procedures as stated in the Technical Memorandum for the Assessment of Noise from Places other than Domestic Premises, Public Places or Construction Sites (IND-TM).  Immediately prior to and following each noise measurement the accuracy of the monitoring equipment was checked using an acoustic calibrator generating a known sound pressure level at a known frequency.  Measurements were accepted as the calibration level from before and after the noise measurement agree to within 1.0 dB.  Noise measurements were made without the presence of fog and rain, and with steady wind speed and gusts not exceeding 5m/s and 10m/s, respectively. 

2) The background noise levels are in the range of 46 - 54dB(A), and therefore the influence of background noise will not be included in the measurement results.

Based on the measured noise data from a kart racing, the measured noise levels show regular pattern over the measured time period, and therefore the measured Leq,5 min represents a 30-minute continuous kart movement.  In addition, for a conservative assessment, the maximum Leq,5 min of 98.2 dB(A) for the 13-kart movement will be adopted in the prediction of operational noise impact.

5.5                                      Assessment Methodology

5.5.1                                Construction Phase

The methodology for the noise impact assessment is in accordance with the procedures outlined in the GW-TM, which is issued under the NCO and the EIAO-TM.  In general, the methodology is as follows:

·       locate representative NSRs that may be affected by the works;

·       determine the plant teams for corresponding activities, based on agreed plant inventories;

·       assign sound power levels (SWLs) to the PME proposed based on the GW-TM or other sources;

·       calculate the correction factors based on the distance between the NSRs and the notional noise source position of the work sites;

·       apply corrections in the calculations such as potential screening effects and acoustic reflection, if any; and

·       predict the construction noise levels at NSRs in the absence of any mitigation measures.

The total SWL associated with each activity was based on an assumed plant inventory, agreed with the Project Proponent.  The notional source position of the work site was established in accordance with the procedures stated in the GW-TM.  Noise impacts at NSRs were subsequently evaluated by comparing the predicted noise levels with the EIAO-TM daytime construction noise limits (Leq, 30min dB(A)), as outlined in Section 5.2.1.

5.5.2                                Operational Phase

The methodology for the noise impact assessment is in accordance with the procedures outlined in the IND-TM, which is issued under the NCO and the EIAO-TM.  The assessment will take into account the distance attenuation, barrier attenuation and corrections of operation mode in accordance with the IND-TM. 

To assess the worst-case noise impact from the karting track, the maximum noise emission of the kart has been taken in the assessment.

5.5.3                                Evaluation of Impacts

Construction Phase

Based on the notional source position as identified in accordance with the procedures stated in the GW-TM, the source-to-NSR distances are presented in Table 5.6.

Table 5.6        Noise Sensitive Receivers

NSR

Location

Approx. Horizontal Distance to Source (m)

N1

No. 32 Pak Long

1153

Based on existing topography, the NSRs do not have direct line of sight to the construction site.  Therefore, with reference to the GM-TM, a negative correction of 10 dB(A) has been included in the construction noise assessment. 

Without the use of mitigation measures, predicted construction noise levels at all NSRs during all construction stages will comply with the stipulated criterion.  Details of the calculations are presented in Annex A.  A summary of the construction noise levels is presented in Table 5.7.  As confirmed by the Project Proponent, there will not be overlapping periods between each construction activities.  Hence cumulative noise impact during the construction period will not be a concern.  Given that the predicted construction noise levels are well within the stipulated noise criterion, mitigation measures are not required to alleviate the noise impacts.

Table 5.7        Construction Noise Levels - Unmitigated (Leq, 30 min dB(A))

 

Construction Noise Levels at Different Stages, Leq, 30 min dB(A)

NSRs

Site Formation

Track Paving

N1

37

35

Operational Phase

Based on the maximum sound pressure level of Leq, 5min 98.2 dB(A) at 1m for 13-kart movement, the facade noise levels at the identified NSRs are predicted and summarised in Table 5.8.  Results indicate that the nearest NSR (N1), which are shielded by the existing topography, will be subject to noise level of 35 dB(A).  Details of the calculations are presented in Annex B.

Table 5.8        Predicted Facade Noise Levels at NSRs

NSRs

Description

Predicted Facade Noise Level, dB(A)

N1

No. 32 Pak Long

35

Results indicated that the predicted facade noise levels will comply with the day-time (ANL-5) noise criterion of 55 dB(A) at all NSRs.   

5.6                                      Mitigation Measures

5.6.1                                Construction Phase

Though the predicted construction noise levels comply with the stipulated noise criterion, good site practice and noise management is recommended for minimising the construction noise impact on nearby NSRs, including: 

·           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 use intermittently, such as vibratory poker, 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 nearby NSRs; and

·           Mobile plant should be sited as far away from NSRs as possible.

5.6.2                                Operational Phase

The noise assessment indicated that based on the maximum sound pressure level of 98 dB(A) at 1 m for 13-kart movement, the predicted facade noise levels for a maximum of 40-kart event will comply with the day-time noise criterion at the nearest NSRs.  No mitigation measures are required.

5.7                                      Environmental Monitoring and Audit

5.7.1                                Construction Phase

Given the compliance with the stipulated noise criterion, noise monitoring is not required during the construction stage. 

5.7.2                                Operational Phase

Given the compliance with the stipulated noise criterion, noise monitoring is not required during the operation stage. 

5.8                                      Conclusion

Due to the large separation distances, unmitigated construction activities associated with the Project will not cause adverse noise impact at the NSRs.  The predicted construction noise levels are in the range of 35 – 37 dB(A), which complied with the stipulated noise criterion.   

Based on the worst case scenario by adopting a maximum sound pressure level of 98 dB(A) at 1 m for 13-kart movement, the predicted facade noise levels for a maximum of 40-kart event is well below the daytime noise criterion of 55 dB(A) at all NSRs located at more than 1km from the site boundary. 

Given the NSRs located at more than 1km and the compliance with the stipulated noise criteria, noise monitoring during the construction and operational phase is not required.