5 NOISE

5.1 Identified Sensitive Receivers

5.1.1 Representative Noise Sensitive Receivers (NSRs) have been identified in accordance with criteria set out in the Environmental Impact Assessment Ordinance (EIAO) and Technical Memorandum on the Environmental Impact Assessment Process (TMEIA).

5.1.2 Preliminary NSRs have been identified in an area 300m either side of the full stretch of the proposed roads. Existing noise sensitive receivers who may be adversely affected by increases in noise as a result of the construction and operation of the improved Tung Chung Road are listed in Table 5.1. The representative NSRs can also be seen in Figures 5.1a to 5.1g. The density of village properties in the Tung Chung Valley, Ha Ling Pei and Wong Ka Wai, has made it necessary to allocate further sensitive receivers in this area for the assessment of construction noise for permanent noise barrier construction and operational noise impacts. The additional sensitive receivers in this area are shown in Figure 5.3a. Visitors to the country park are also potentially sensitive to impacts but as no permanent facilities, such as camp grounds, are affected and all other visitors would be transient in nature, no significant impacts are predicted.

5.1.3 In addition to the above, the Cheung Sha Layout Plan – Lantau Island, Plan No. L/I-CS/1, has identified several future sales sites in the vicinity of the junction of the new Tung Chung Road with the South Lantau Road. These sites have been allocated for future low rise 2 storey residential development. The boundaries of the site are indicative only and the layout of the properties is not known at this time. However, representative locations at the sites which are closest to the proposed road have been selected at the site boundaries in order to assess the potential impacts to any future receivers, as shown on Figure 5.1e. The properties will not be constructed and occupied until after the opening of the proposed widened Tung Chung Road and as such the representative ASRs are relevant to the operational phase of the project only.

Table 5.1: Noise Sensitive Receivers

Figures No.	NSR Ref.	NSR		No. of Floor	Shortest Slant Distance (m)	Description
5.1a/5.3a	SR1	8, Ha Ling Pei		3	235	Residential
	SR2	7, Wong Ka Wai		3	119	Residential
	SR3	Village House		3	256	Residential
	SR4	8, Lung Tseng Tau		3	56	Residential
	SR5	Village House		3	168	Residential
5.1b	SR6	41, Shek Lau Po		3	246	Residential
	SR7	Village House		3	198	Residential
	SR8	1, Shek Mun Kap		3	230	Residential
5.1c	SR9	AFCD Staff Quarters		1	156	Residential

5.1d	SR10	74, Leyburn Villas		2	298	Residential
5.1e	SR11	12, Cheung Sha Sheung Tsuen		3	277	Residential
	SR12	32, Cheung Sha Sheung Tsuen		3	266	Residential
	SR13	31B, South Lantau Road		2	35	Residential
	SR14	Village House		2	153	Residential
	SR15	YWCA Youth Camp		1	55	Residential
5.1f	SR16	Block 1, Acacia Villa		3	161	Residential
	SR17	37, South Lantau Road		3	234	Residential
	SR18	39, South Lantau Road		3	289	Residential
5.1g	SR19	Block 17, Butterfly Crest		3	#	Residential
Additional Sensitive Receivers in Tung Chung Valley
5.3a	SR1A	10, Ha Ling Pei	3		273	Residential
	SR1B	8, Ha Ling Pei	3		256	Residential
	SR1C	7, Ha Ling Pei	3		215	Residential
	SR2A	14, Wong Ka Wai	3		165	Residential
	SR2B	9, Wong Ka Wai	3		132	Residential
	SR2C	7, Wong Ka Wai	3		99	Residential
	SR2D	3A, Wong Ka Wai	3		83	Residential
	SR4A	10A, Lung Tseng Tau	3		60	Residential
	SR4B	7, Lung Tseng Tau	3		45	Residential
	SR4C	13, Lung Tseng Tau	3		55	Residential
	SR4D	28, Lung Tseng Tau	3		34	Residential
Future Sensitive Receivers in Cheung Sha⁽¹⁾
5.1f	CS1	Cheung Sha future sale site	2		35⁽²⁾	Residential
	CS2	Cheung Sha future sale site	2		32⁽²⁾	Residential
	CS3	Cheung Sha future sale site	2		56⁽²⁾	Residential
	CS4	Cheung Sha future sale site	2		53⁽²⁾	Residential
	CS5	Cheung Sha future sale site	2		25⁽²⁾	Residential
	CS6	Cheung Sha future sale site	2		20⁽²⁾	Residential
	CS7	Cheung Sha future sale site	2		20⁽²⁾	Residential
	CS8	Cheung Sha future sale site	2		25⁽²⁾	Residential
	CS9	Cheung Sha future sale site	2		29⁽²⁾	Residential
	CS10	Cheung Sha future sale site	2		33⁽²⁾	Residential
	CS11	Cheung Sha future sale site	2		50⁽²⁾	Residential
	CS12	Cheung Sha future sale site	2		22⁽²⁾	Residential
	CS13	Cheung Sha future sale site	2		42⁽²⁾	Residential

Note: # The distance between SR19 and the improved Tung Chung Road is more than 500m and thus it will only be potentially affected by the slope remediation works on the obsolete sections of the existing Tung Chung Road during the construction phase

(1): Future sensitive receivers relevant to the operational phase only.

(2): Based upon assumed locations of sensitive receivers only and site boundaries are indicative.

5.1.4 All the sensitive receivers are residential and, thus, the noise criteria for general construction work during normal working hours (0700 to 1900 hours on any day not being Sunday and Public Holiday) will be 75 dB(A) (L_{eq (30mins)}) and 70 dB(A) (L_10(1hour)) for the operational phase as detailed in Section 3.

5.1.5 The Remaining Development in Tung Chung and Tai Ho Comprehensive Feasibility Study has also proposed sensitive development on the fringes of Tung Chung, close to the northern edge of the project and these could be adversely affected by the operation of the improved Tung Chung Road. The impacts on these sensitive receivers are reported separately in Section 12 of this report.

5.2 Baseline Conditions

5.2.1 The majority of the proposed road, with the exception of the northern and southern end, is situated within very quiet rural areas, with the surrounding land comprising country parks, open space and agricultural activities. Noise levels for the majority of the study area are very low, the only major noise sources is the traffic of existing Tung Chung Road.

5.2.2 Noise levels at the northern end of the alignment in Tung Chung are influenced by traffic from the Yu Tung Road and existing Tung Chung Road. The southern end of the alignment connects with the South Lantau Road and thus, noise levels in this area are higher due to the presence of road traffic.

5.3 The Proposed Scheme

5.3.1 Construction Activities

5.3.1.1 The construction equipment for each stage of the project has been determined and the sound power level (SWL) of each piece of equipment is based upon the Technical Memorandum on Noise From Construction Work Other Than Percussive Piling and BS5228 when the SWL are not listed in the Technical Memorandum. No percussive piling is anticipated for the Project.

5.3.1.2 The construction activities for the Project can be divided into four broad areas, namely roadworks and bridgeworks for the main alignment, slope stabilisation works and slope remediation works for the obsolete section of the existing Tung Chung Road. The key construction activities within these broad activities will include:

(i) Roadworks - earthworks

(including utility works) - retaining wall construction (required for all

areas not on structure); and

- pavement construction.

(ii) Bridgeworks: - foundation construction; and

- deck construction.

(iii) Slope Stabilisation - soil nailing/rock dowelling; and

- equipment transportation.

(iv) Slope Remediation - earthworks; and

- slope nailing.

(v) Noise Mitigation - foundation construction; and

- erection.

5.3.1.3 The individual pieces of equipment required for each of these stages have been highlighted in Section 2. The construction plant has been further divided into working scenarios for each of the broad construction activities as detailed in Table 5.2 below:

Table 5.2: Equipment Scenarios

Main Activity	Sub-Activity	Equipment Scenario	Scenario Reference
Roadworks	Earthworks⁽¹⁾	Scenario 1 - Rock/earth excavation	E1
		Scenario 2 - Removal /spreading of earth/rock	E2
		Scenario 3 - Forming of earthworks.	E3
	Retaining Wall Construction	Scenario 1 - Foundation works	R1
		Scenario 2 - Piling	R2
		Scenario 3 - Formwork/concreting.	R3
		Scenario 4 - Backfilling Works	R4
	Pavement Construction ⁽¹⁾	Scenario 1 - Preparation of Roadbase	P1
		Scenario 2 - Laying of Surface Material	P2
		Scenario 3 - Road Marking	P3
Bridgeworks	Foundation Construction	Scenario 1 - Excavation	F1
		Scenario 2 - Piling	F2
		Scenario 3 - Formwork	F3
		Scenario 4 - Concreting	F4
	Deck Construction	Scenario 1 - Formworks	D1
		Scenario 2 - Concreting	D2
		Scenario 3 - Deck elevation	D3
Slope⁽²⁾ Stabilisation	Rock Dowelling	Scenario 1 – Rock dowelling	SS1
Slope⁽²⁾ Stabilisation	Equipment Transportation	Scenario 1 – Delivery by helicopter	SS2
Slope ⁽²⁾ Remediation	Earthworks	Scenario 1 – Earthworks	SR1
Slope ⁽²⁾ Remediation	Slope Nailing	Scenario 1 – Slope Nailing	SR2
Noise Mitigation	Foundations and Erection	Scenario 1 – Foundation Works	NB1
		Scenario 2 – Piling	NB2
		Scenario 3 – Formwork/Concreting	NB3
		Scenario 4 – Backfilling Works	NB4
		Scenario 5 - Erection	NB5

Notes (1): Includes minor works associated with utilities.

(2): No drainage works are required for the slope stabilisation works. Noise associated with the drainage and shotcreting works for the remediation of slopes on the existing Tung Chung Road are considered to be minor but covered in Table 5.8d.

5.3.1.4 The equipment included in each of these scenarios, together with the appropriate sound power levels are provided in Tables 5.3 to 5.7 below for roadworks, bridge works, slope stabilisation works, slope remediation works and noise mitigation works respectively. As noted, in Section 2.7.2, the equipment lists have been confirmed by the Project Proponent as being practical for completing the works.

Table 5.3: Typical Equipment Requirement for Road Construction

CNP Equipment Code	Equipment Scenario	Sound Power Level (SWL) in dB(A)	Number of Equipment	Total Sound Power Level (SWL) in dB(A)
Earthworks
Scenario E1	Excavation of earth / rock and removal
028	Breaker	122	2	125.9
067	Dump Truck	117	1
081	Excavator	112	1
282	Water Pump (Petrol)	103	1
Scenario E2	Spreading of earth / rock
030	Bulldozer	115	1	119.5
067	Dump Truck	117	1
204	Scraper	109	1

Scenario E3	Forming of earthworks
030	Bulldozer	115	1	120.7
104	Grader	113	1
067	Dump Truck	117	1
186	Roller Vibratory	108	1
050	Compactor	105	1
169	Power Rammer (Petrol)	108	1
Retaining wall construction
Scenario R1	Foundation works
028	Breaker	122	2	125.9
067	Dump Truck	117	1
081	Excavator	112	1
282	Water Pump (Petrol)	103	1
Scenario R2⁽¹⁾	Piling
164	Piling Rig	115	1	116.9
282	Water Pump	103	1
141	Lorry	112	1
165	Piling, large diameter bored, oscillator *	115	1
Scenario R3	Formwork / concreting
044	Concrete Lorry Mixer	109	1	117.9
170	Poker	113	1
101	Generator	108	1
201	Saw, circular	108	1
282	Water pump	103	1
043	Chipper	112	1
066	Dumper	106	1


CNP Equipment Code	Equipment Scenario	Sound Power Level (SWL) in dB(A)	Number of Equipment	Total Sound Power Level (SWL) in dB(A)
Scenario R4	Backfilling works
050	Compactor Vibratory	105	1	117.8
067	Dump Truck	117	1
186	Roller Vibratory	108	1
	Pavement Construction
Scenario P1	Preparation of Roadbase
186	Vibratory roller	108	1	118.6
067	Dump truck	117	1
081	Excavator	112	1
Scenario P2	Laying of Surface Material
004	Asphalt paver	109	1	119.0
185	Road roller	108	1
067	Dump Truck	117	1
186	Vibratory roller	108	1
044	Concrete Lorry Mixer	109	1
Scenario P3	Road Marking
161	Paint line marker	90	1	115.0
203	Saw	115	1	115.0

* The piling oscillator will be required to be used with the piling rig (CNP 164). However, as these pieces of equipment will be used alternately and never concurrently, the total SWL has been based upon the SWL of only one piece of equipment (ie one SWL of 115 only).

(1) The equipment which will be used for the detailed ground investigation will be similar to that required for the bored piling. However, the bored piling rig will be noisier than the rig used for the ground investigation.

Table 5.4: Typical Equipment Requirement for Bridge Construction

CNP Equipment Code	Equipment Scenario	Sound Power Level (SWL) in dB(A)	Number of Equipment	Total Sound Power Level (SWL) in dB(A)
Deck Construction
Scenario D1	Formwork
021	Bar Bender and cutter	90	1	119.8
171	Planer	117	1
101	Generator	108	1
201	Saw	108	1
043	Chipper, hand-held	112	1
141	Lorry	112	1
Scenario D2	Concreting
044	Concrete lorry mixer	109	1	115.5
047	Concrete pump	109	1
170	Poker	113	1
Scenario D3	Elevation
048	Crane	112	1	112.0

Foundation/Pier Construction
Scenario F1	Excavation
027	Breaker	122	2	125.9
067	Dump truck	117	1
081	Excavator	112	1
282	Water Pump	103	1
Scenario F2	Piling
164	Piling Rig	115	1	119.1
283	Water Pump	85	1
067	Dump Truck	117	1
165	Piling, large diameter bored, oscillator*	115	1
Scenario F3	Formwork
021	Bar Bender	90	1	118.0
171	Planer	117	1
101	Generator	108	1
201	Saw	108	1
Scenario F4	Concreting
047	Concrete pump	109	1	115.5
044	Concrete lorry mixer	109	1
170	Poker	113	1

Table 5.5 Typical Equipment Requirement for Slope Stabilisation Works

CNP Equipment Code	Equipment Scenario	Sound Power Level (SWL) in dB(A)	Number of Equipment	Total Sound Power Level (SWL) in dB(A)
Rock Dowelling
Scenario SS1	Rock Dowelling
183	Rock Drill, hand held	116	1	116.3
003	Compressor	104	1	116.3
Equipment Transportation
Scenario SS2	Delivery by Helicopter⁽¹⁾

(1) The assessment of helicopter noise has been based upon the L_max for typical helicopter models and not the SWL.

Table 5.6 Typical Equipment Requirement for Slope Remediation Works

CNP Equipment Code	Equipment Scenario	Sound Power Level (SWL) in dB(A)	Number of Equipment	Total Sound Power Level (SWL) in dB(A)
Slope Remediation Earthworks
Scenario SR1	Earthworks
081	Excavator	112	1	118.2
067	Dump Truck	117	1	118.2
Slope Nailing
Scenario SR2	Slope Nailing
183	Rock Drill, hand held	116	1	116.3
003	Compressor	104	1	116.3

Table 5.7 Typical Equipment Requirement for the Construction of Permanent Noise Barrier in Tung Chung Valley

CNP Equipment Code	Equipment Scenario	Sound Power Level (SWL) in dB(A)	Number of Equipment	Total Sound Power Level (SWL) in dB(A)
Noise Barrier Construction
Scenario NB1	Foundation works
Scenario NB1A
026	Breaker, Hand Held	114	1	114.3
002	Air compressor	102	1
Scenario NB1B
081	Excavator	112	1	112.5
282	Water Pump	103	1
Scenario NB1C
141	Lorry with grab#	112	1	112.0
Scenario NB2	Piling
-	Mini Piling Rig*	113	1 1	113.4
282	Water Pump	103	1 1
Scenario NB3	Formwork / concreting
044	Concrete Lorry Mixer	109	1	114.8
170	Poker	113	1
282	Water pump	103	1
Scenario NB4	Backfilling works
Scenario NB4A
050	Compactor Vibratory	105	1	105.0
Scenario NB4B
141	Lorry with grab#	112	1	112.0

Scenario NB5	Erection
Scenario NB5A
141	Lorry with grab#	112	1	112.0
Scenario NB5B
048	Crane	112	1	112.0

CNP

Equipment Code

Equipment Scenario

Sound Power

Level (SWL) in dB(A)

Number of Equipment

Total Sound Power Level (SWL) in dB(A)

Noise Barrier Construction

Scenario NB1

Foundation works

Scenario NB1A

026

Breaker, Hand Held

114

114.3

002

Air compressor

102

Scenario NB1B

081

Excavator

112

112.5

282

Water Pump

103

Scenario NB1C

141

Lorry with grab#

112

112.0

Scenario NB2

Piling

Mini Piling Rig*

113

113.4

282

Water Pump

103

Scenario NB3

Formwork / concreting

044

Concrete Lorry Mixer

109

114.8

170

Poker

113

282

Water pump

103

Scenario NB4

Backfilling works

Scenario NB4A

050

Compactor Vibratory

105

105.0

Scenario NB4B

141

Lorry with grab#

112

112.0

Scenario NB5

Erection

Scenario NB5A

141

Lorry with grab#

112

112.0

Scenario NB5B

048

Crane

112

112.0

* See Table C.10, item 6 of BS 5228 for SWL

# Lorry (CNP 141) is assumed for the purposes of the noise assessment.

5.3.2 Predicted Traffic Flows

5.3.2.1 Predicted traffic flows used in the operational noise assessment have been discussed in Section 2.8 of this report. Transport Department have approved the traffic figures for use in the EIA and their approval is presented in Appendix G.

5.4 Construction Noise Impact Assessment

5.4.1 Assessment Methodology

5.4.1.1 The assessment of the proposed alignment has comprised an evaluation of the construction noise impacts at representative sensitive receivers along its length based upon the full range of construction activity scenarios detailed above. The construction noise at the NSRs has been assessed in accordance with the methodology of the Technical Memorandum on Noise from Construction Work Other than Percussive Piling. The noise impact from the use of a helicopter to deliver slope stabilisation equipment has also been assessed. While the assessment of construction noise has been based upon non-restricted periods, this does not preclude the Contractor from working in restricted periods should this be required. However, any work in restricted periods will be subject to the Contractor obtaining a valid Construction Noise Permit under the Noise Control Ordinance as detailed in Section 3.3.2. It is likely that working up to 11.00pm will be required and further assessment of this period is presented in Section 5.4.3.12 below.

5.4.1.2 Potential cumulative impacts associated with the construction of the development in Tung Chung Valley are assessed in Section 12. There are no other cumulative impacts from other contemporary projects in the vicinity.

5.4.1.3 Construction activities on site will involve the use of heavy machinery and as detailed in Section 5.3, an indicative schedule of key equipment to be used, activities to be carried out and duration of each segment of the works has been identified. Based upon the number and type of heavy plant to be employed in the construction works, noise levels generated will probably be high and impacts are a key issue.

5.4.2 Assessment Findings

5.4.2.1 The maximum noise levels at the NSRs during the construction phase of the alignment without noise mitigation measures applied are shown below in Tables 5.8a and 5.8b for the road earthworks and bridge works respectively, Tables 5.8c and 5.8d for the slope stabilisation and slope remediation respectively and Table 5.8e for the permanent noise barrier construction. The detailed modelling result is provide in Appendix F and a summary of the maximum unmitigated levels at each NSR is provided in Figures 5.2a to 5.2e.

Table 5.8a Maximum Noise Levels (dB(A)) during Road Construction without Noise Mitigation

Sensitive Receiver	Slant Distance (m)	Noise Level without Mitigation, dB(A)
	(EW+PC/RW)⁽¹⁾	Earth Works			Retaining Wall				Pavement Construction
	Scenario	E1	E2	E3	R1	R2⁽²⁾	R3	R4	P1	P2	P3
	SWL	125.9	119.5	120.7	125.9	116.9	117.9	117.8	118.6	119.0	115.0
SR1	235/325	73	67	68	71	62	63	63	66	67	63
SR2	114/238	80	73	75	73	64	65	65	72	73	69
SR3	256/425	73	66	68	68	59	60	60	65	66	62
SR4	56/162	86	80	81	77	68	69	69	79	79	75
SR5	162/211	77	70	72	74	65	66	66	69	70	66
SR6	244/248	73	67	68	73	64	65	65	66	66	62
SR7	202/206	75	68	70	75	66	67	66	67	68	64
SR8	229/241	74	67	68	73	64	65	65	66	67	63
SR9	156/161	77	71	72	77	68	69	69	70	70	66
SR10	276/271	72	66	67	72	63	64	64	65	65	61
SR11	267/272	72	66	67	72	63	64	64	65	65	61
SR12	263/252	72	66	67	73	64	65	65	65	66	62
SR13	32/32	91	84	86	91	82	83	83	83	84	80
SR14	151/145	77	71	72	78	69	70	70	70	70	66
SR15	55/96	86	80	81	81	72	73	73	79	79	75
SR16	166/164	76	70	71	77	68	69	68	69	70	66
SR17	240/234	73	67	68	73	65	66	65	66	66	62
SR18	291/291	72	65	66	72	63	64	63	64	65	61

76	Noise Level at the sensitive receiver exceeds relevant criteria of 75dB(A) for domestic premises

(1): The first distance quoted relates to both earth works and pavement construction and the second distance in the column is from the NSR to the nearest retaining wall works. Locations of retaining walls are shown in Figures 5.1a to f.

(2): Equipment for the piling activities assumed to be noisier than that required for the detailed ground investigation. However, based upon a worst case scenario, predicted noise levels for scenario R2 could be used to represent GI works.

Table 5.8b Maximum Noise Levels (dB(A)) at NSRs during Bridge Construction without Noise Mitigation

Sensitive Receiver*		Slant Distance (m)	Noise Level without Mitigation, dB(A)
		Slant Distance (m)	Deck Construction			Foundation Construction
		Scenario	D1	D2	D3	F1	F2	F3	F4
		SWL	119.8	115.5	112.0	125.9	119.1	118.0	115.5
SR9		159	71	67	63	77	70	69	67
SR10		277	66	62	58	72	65	64	62
SR11		323	65	60	57	71	64	63	60
SR12		295	65	61	58	71	65	64	61
SR13		231	67	63	60	74	67	66	63
SR14		206	68	64	61	75	68	67	64
SR15		218	68	64	60	74	67	66	64
SR16		375	63	59	56	69	63	62	59
SR17		460	62	57	54	68	61	60	57
SR18		501	61	57	53	67	60	59	57

76	Noise Level at the sensitive receiver exceeds relevant criteria of 75dB(A) for domestic premises

* The distance between the SR1 to SR9, SR19 and the construction work is more than 500 metres, as such noise levels would not exceed the relevant noise criteria.

Table 5.8c Maximum Noise Levels (dB(A)) at NSRs during Slope Stabilisation Works without Noise Mitigation

Sensitive Receiver		Slant Distance (m)	Noise Level without Mitigation, dB(A)
		Scenario	Rock Dowelling (SS1)
		Total SWL	116.3
SR1		325	61
SR2		238	64
SR3		425	59
SR4		162	67
SR5		211	65
SR6		248	63
SR7		206	65
SR8		241	64
SR9		161	67
SR10		271	63
SR11		272	63
SR12		252	63
SR13		380	60
SR14		145	68
SR15		96	72
SR16		164	67
SR17		234	64
SR18		291	62

76	Noise Level at the sensitive receiver exceeds relevant criteria of 75dB(A) for domestic premises.

* Noise from transport of equipment by helicopter assessed below

Table 5.8d Maximum Noise Levels (dB(A)) at NSRs during Slope Remediation without Noise Mitigation

Sensitive Receiver*	Slant Distance (m)	Noise Level with Mitigation, dB(A)
	Slant Distance (m)	Earthwork	Soil Nailing
	Scenario	SR1	SR2
	SWL	118.2	116.3
SR19	90	74	72

Note: * SR1 to SR18 located near the improved Tung Chung Road, and will not affected by the slope remediation work on the obsolete section of the existing Tung Chung Road. (see Figures 2.12 and 2.13).

** Drainage works and shotcreting works associated with the slope remediation works would involve a concrete pump (CNP047) and a concrete mixer (CNP046) with a combined SWL of 109 dB(A). Based upon the fact that no adverse impacts have been predicted for the above noisier scenarios SR1 and SR2, no impacts from the drainage works are expected.

Table 5.8e Maximum Noise Levels (dB(A)) during Construction of Permanent Noise Barrier in Tung Chung Valley without Noise Mitigation

Sensitive Receiver	Slant Distance (m)	Noise Level without Mitigation, dB(A)
	Slant Distance (m)	Construction of Noise Barrier
	Scenario	NB1A	NB1B	NB1C	NB2	NB3	NB4A	NB4B	NB5A	NB5B
	SWL	114.3	112.5	112.0	113.4	114.8	105.0	112.0	112.0	112.0
SR1A	200	63	61	61	62	64	54	61	61	61
SR1B	179	64	62	62	63	65	55	62	62	62
SR1	153	66	64	63	65	66	56	63	63	63
SR1C	149	66	64	64	65	66	57	64	64	64
SR2A	96	70	68	67	69	70	60	67	67	67
SR2B	60	74	72	71	73	74	64	71	71	71
SR2	40	77	75	75	76	78	68	75	75	75
SR2C	21	83	81	81	82	83	74	81	81	81
SR2D	25	81	80	79	80	82	72	79	79	79
SR3	242	62	60	59	61	62	52	59	59	59
SR4A	50	75	74	73	74	76	66	73	73	73
SR4	48	76	74	73	75	76	66	73	73	73
SR4B	39	77	76	75	77	78	68	75	75	75
SR4C	46	76	74	74	75	77	67	74	74	74
SR4D	25	81	80	79	80	82	72	79	79	79
SR5	168	65	63	62	64	65	55	62	62	62

Note: * SR6 to SR19 are located more than 300 meters away from the barrier construction works and thus will not be affected by these works.

76	Noise Level at the sensitive receiver exceeds relevant criteria of 75dB(A) for domestic premises

Transportation of Slope Stabilisation Equipment by Helicopter

5.4.2.2 As highlighted previously, some equipment required high up the hills may need to be transported by helicopter. The areas where the slope stabilisation works will be required are shown by the limit of slope stabilisation in the figures in Section 2. Based upon the works, there is the potential for short term noise impacts on the local residents.

5.4.2.3 The TMEIA specifies a maximum level for helicopter noise at sensitive receivers which is 85 L_max dB(A). However, if the helicopter is considered to be a piece of construction equipment then the 75 dB(A) at the sensitive receivers should be met. Thus, in order to provide a full assessment, comparison to both these standards has been made.

5.4.2.4 Based upon two common helicopter types used in Hong Kong, the L_max dB(A) of each are detailed in Table 5.9 as follows:

Table 5.9 L_max dB(A) of Common Helicopter Types in Hong Kong

Brand

Model

Users

Reference Height⁽¹⁾

L_maxdB(A) ⁽¹⁾

Sikorsky

S76

Government Flying Service, Private

244m (800 feet)

78dB(A)

Aerospatiale

(Eurocopter)

AS355

Private

153m (500 feet)

77dB(A)

Note (1): Source: UK Institute of Acoustics (IOA), Volume 14, Part 4 (1992) “Noise Levels of Helicopters Performing Elevated Pad Take-off and Landing Procedures”.

5.4.2.5 The impact of noise from the helicopter can be calculated at the facades of the representative NSRs in terms of maximum L_Amax using basic acoustic principles as follows:

At a specified distance, say D1, the Sound Pressure Level (Lp) should be

Lp(at D1) = Lw - distance attenuation (D1) ……(1)

where Lw is the Sound Power Level

Since the helicopter noise is a point source, then (1) can be converted:

Lp(at D1) = Lw - 20log(D1) ……(2)

At distance D2, then

Lp(at D2) = Lw - 20log (D2) ……(3)

Rearrange (2) and (3)

Lw=Lw, then,

Lp(at D1) + 20log (D1) = Lp (at D2) + 20 log(D2), and

Lp(at D2) = Lp(at D1) + 20log (D1) - 20log (D2), and

Lp(at D2) = Lp(at D1) + 20(log(D1/D2)) ……(4)

Equation (4) can be used to convert the reference noise level from the helicopter measurement to the noise level at a specified distance. The facade correction factor is then included.

5.4.2.6 The predicted noise levels in L_max dB(A) based on the two different helicopter types at a set of distances from noise sensitive receivers are shown in Table 5.10 below.

Table 5.10 Predicted Helicopter Noise (L_max dB(A))

Distance (metres)	Sikorsky S76		Aerospatiale AS355
	Reference Noise Level 78	Reference Distance, 244 m	Reference Noise Level 77	Reference Distance, 153 m
	Noise Level (non-building)	Noise Level (facade)	Noise Level (non-building)	Noise Level (facade)
10	106	109	101	104
20	100	103	95	98
30	96	99	91	94
40	94	97	89	92
50	92	95	87	90
60	90	93	85	88
70	89	92	84	87
80	88	91	83	86
90	87	90	82	85
100	86	89	81	84
110	85	88	80	83
120	84	87	79	82
130	83	86	78	81
140	83	86	78	81
150	82	85	77	80
160	82	85	77	80
170	81	84	76	79
180	81	84	76	79
190	80	83	75	78
200	80	83	75	78
210	79	82	74	77
220	79	82	74	77
230	79	82	73	76
240	78	81	73	76
250	78	81	73	76
260	77	80	72	75
270	77	80	72	75
280	77	80	72	75
290	76	79	71	74
300	76	79	71	74
310	76	79	71	74
320	76	79	71	74
330	75	78	70	73
340	75	78	70	73
350	75	78	70	73
360	75	78	70	73
370	74	77	69	72
380	74	77	69	72
390	74	77	69	72
400	74	77	69	72
410	73	76	68	71
420	73	76	68	71
430	73	76	68	71
440	73	76	68	71
450	73	76	68	71
460	72	75	67	70
470	72	75	67	70
480	72	75	67	70
490	72	75	67	70
500	72	75	67	70

5.4.2.7 In accordance with Hong Kong’s Civil Aviation Department requirements, helicopters must operate outside a 500ft (152 metres) ceiling from residential properties. This distance, will, therefore, be the shortest distance between the noise sensitive receivers and any helicopter noise. Based upon the results in Table 5.9, it can be seen that the maximum noise of both helicopter types would not exceed the 85dB(A) noise limit at this distance.

5.4.2.8 Based upon the testing and investigation, the approximate area for slope stabilisation works is shown in Section 2. The distance between slope stabilisation work and the nearest sensitive receivers is about 500 metres. According to the result shown in Table 5.10, the L_max for the helicopter, the Sikorsky S76 and Aerospatiale AS355, is 75 and 70 dB(A) at 500m respectively which is within the 85 dB(A) criteria. The noise at the sensitive receivers is also within the 75 dB(A) noise criteria if the helicopter is considered to be a piece of construction equipment.

5.4.2.9 The helicopter pick-up location will be located at the proposed Contractor’s works area which is shown in Figure 2.10. This area is 400 meters away from the nearest existing noise sensitive receivers. Based upon this distance and the levels provided in Table 5.10 above, the maximum noise level at the closest sensitive receiver would be 77 and 72 for the Sikorsky S76 and Aerospatiale helicopters respectively. Thus, the Sikorsky S76 helicopter would marginally exceed the noise criteria 75dB(A) if the helicopter remained on the works area for a period of 30 minutes.

5.4.2.10 It has been determined that in order to meet the 75 dB(A) standard, the operation of the helicopter at the pick-up location should be restricted to 60%, which equates to the helicopter operating for only 18 minutes in any half hour period at the pick-up point. This period is more than sufficient for the helicopter to remove or drop off equipment in this location and move away. In addition, the scenarios assessed are the worst case, with noise levels being lower with a quieter helicopter.

5.4.2.11 Thus, no unacceptable impacts are predicted from the use of the helicopter, as is the case for the slope stabilisation and slope remediation activities associated with the new road.

5.4.2.12 However, the results detailed above for road construction, bridge construction and noise barrier construction in Tung Chung Valley indicate that, the maximum noise levels at some of the NSRs will exceed the day time noise criteria of 75dB(A). Mitigation measures are, therefore, required to reduce the noise levels to meet the standards. Recommended mitigation measures are detailed in Section 5.4.3.

5.4.3 Construction Mitigation Measures

5.4.3.1 Based upon the anticipated construction scenarios for the main alignment, the maximum noise levels at the closest NSRs would exceed the 75dB(A) noise guideline for non restricted hours at residential properties during road construction and permanent noise barrier construction. Thus, the following noise mitigation measures should be implemented to reduce the construction noise to an acceptable level. The noise mitigation measures and the sound reduction estimated are based on current noise control technologies and BS5228 and have been confirmed by the Project Proponent as being practical.

5.4.3.2 Noise mitigation measures are recommended at SRs 2, 4, 5, 9, 13-16 during road construction and SR9 during bridge construction and SRs 2 and 4 in Tung Chung Valley during permanent noise barrier construction as detailed below in Tables 5.11 and 5.12 respectively.

Table 5.11: Recommended Mitigation Measures for the Noisy Equipment during Road Construction and Bridge Construction

Plant	Mitigation Measures*	Noise Reduction, dB(A)*	Reduction Assumed, dB(A)
· Breaker (Excavator Mounted)	¨ Fit suitably designed muffler or sound reduction equipment. ¨ Use dampened bit to eliminate ringing	Up to 15	5

· Dump Truck · Excavator · Bulldozer · Concrete Lorry Mixer	¨ Fit more efficient exhaust sound reduction equipment ¨ Manufacturers’ enclosure panels should be kept closed	5 to 10	5
· Chipper · Poker	¨ Fit suitably designed muffler or sound reduction equipment. ¨ Ensure all leaks in air line are sealed ¨ Use dampened bit to eliminate ringing	Up to 15	5

* Reference: Noise and vibration control on construction and open sites, BS5228: Part 1: 1997, P.15-16.

Table 5.12 Recommended Mitigation Measures for the Noisy Equipment during Permanent Noise Barrier Construction

Plant

Mitigation Measures*

Noise Reduction, dB(A)*

Reduction Assumed, dB(A)

Table 5.9 Lmax dB(A) of Common Helicopter Types in Hong Kong

Table 5.9 L_max dB(A) of Common Helicopter Types in Hong Kong