CIVL 395 Environmental Impact Assessment [4]

Housing Development in Tuen Mun Area 1Proposed Bridge at Tuen Mun Area 18

HS Kan

March 2007

Air Impact Assessment – CALINE4

www.dot.ca.gov/hq/env/air/index.htm

Noise Impact Assessment

Noise measurement – A-weighting for human perception

Facade Noise Levels from Road Traffic(Extracted from

The Hong Kong Planning Standards & Guidelines, Planning Department)

Peak hourtraffic flow 

(veh/h)

Facade noise levels L10(1h),

dB(A) -Vehicular

speed (30 kph)

Facade noise levels L10(1h),

dB(A) -Vehicular

speed (50 kph)

Facade noise levels L10(1h),

dB(A) -Vehicular

speed (70 kph)

Facade noise levels L10(1h),

dB(A) -Vehicular

speed (85 kph)

Facade noise levels L10(1h),

dB(A) -Vehicular

speed (100kph)

250 70 71 72 73 74

500 73 74 75 76 77

1000 76 77 78 79 80

2000 79 80 81 82 83

3000 80 81 82 83 84

5000 83 84 85 86 87

10000 86 87 88 89 90

Noise Impact Assessment Legislation, standards and criteria

Noise Control Ordinance Technical Memorandum on Noise from Places other than Domestic Premises, Public Places or Co

nstruction Sites Technical Memorandum on Noise from Construction Work other than Percussive Piling

http://www.epd.gov.hk/epd/english/environmentinhk/noise/guide_ref/tm_nonpp.html Technical Memorandum on Noise from Percussive Piling

Noise sensitive receivers All domestic premises, hotel, hospital, educational institution, place of public worship, library, co

urt, arts performance facilities, etc Area Sensitivity Ratings ASR

Urban / rural / low-density residential Table 1 in the Technical Memorandum

Influencing factors IF (on the ASR) Presence of industrial areas, major roads, etc

Basic noise levels BNL Table 2 in the Technical Memorandum

Sound levels for Powered Mechanical Equipment PME Table 3 in the Technical Memorandum For summation of different sources, Table 4 in the Technical Memorandum

Acceptable noise levels ANL For this exercise, you may take the ANL as being directly equal to the BNL

Distance attenuation Distance attenuation in dB(A) = 20 log D + 8, where D = distance in m Table 5 in the Technical Memorandum

Outline Zoning Plan of the Bridge Site

Source:

The Planning Department website

          

Government / Institution / Community

Green Belt

  Open Space

 Residential (Group A)

                

Proposed Bridge at Tuen Mun Area 18

(1) During

foundation works: bored piling machine, air compressor, excavator, steel bender, etc;

(2) During pile construction: concrete truck mixer, concrete pump, vibratory poker, etc.

(3) etc.

Consider mainly the noise impact from powered mechanical equipment at the southern abutment at various stages, e.g.

Table 1 - Area Sensitivity Ratings (ASRs)

Type of Area Containing NSR Degree to which NSR is affected by IF

  Not Affected Indirectly Affected

Directly Affected

Rural area, including country parks or village type developments

A B B

Low density residential area consisting of low-rise or isolated high-rise developments

A B C

Urban area B C C

Area other than those above

B B C

Basic Noise Levels (BNLs)

Time Period ASR

A B C

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

60 65 70

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

45 50 55

Table 2 of the Technical Memorandum

Table 4 - Summation of Noise Levels

Difference in dB(A) between two noise levels being summed

Amount in dB(A) to add to the higher noise level

0 to 0.5 3.0

1.0 to 1.5 2.5

2.0 to 3.0 2.0

3.5 to 4.5 1.5

5.0 to 7.0 1.0

7.5 to 12.0 0.5

more than 12.0 0

Control of Noise Impact

The Source Elimination, Reduction, Shielding, Absorption

The Transmission Breaking, Weakening

The Receiver Shielding, Protection, Removal

Source ReceiverTransmission

Noise Impact Assessment

Control and mitigation Construction

Choice of construction method Use of silenced powered mechanical equipment Proper equipment maintenance Proper location and orientation of equipment Noise screens Good site practices

Operation Reduction Containment Shielding Protecting the receiver

Cantilever Barrier at West Kowloon Expressway

Enclosure barrier at Wong Chu Road, Tuen Mun