NOISE POLLUTION CHAPTER 9

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2 NOISE POLLUTION CHAPTER 9
Matakuliah : S Teknik Lingkungan Tahun : 2009 NOISE POLLUTION CHAPTER 9

3 Definisi Noise (bising) adalah bunyi yang tidak dikehendaki, suatu gejala lingkungan (environmental phenomenon) yang mempengaruhi manusia sejak dalam kandungan dan sepanjang hidupnya. Bising: setiap bunyi yang dapat mengakibatkan pengaruh fisiologis dan psikologis pada individu dan dapat mengganggu kehidupan sosial individu atau kelompok. Bising pada intensitas dan lama waktu tertentu dapat mempengaruhi hilangnya pendengaran secara sementara (temporary) atau tetap (permanen) dari ketulian yang ringan sampai tuli secara total. Bina Nusantara University

4 Gelombang Bunyi Dihasilkan oleh getaran dari benda-benda padat atau pemisahan cairan yang bergerak sekitar atau memalui lubang dalam benda padat. Getaran dan atau pemisahan ini menyebabkan udara disekelilingnya mengalami tekanan (compression) dan pelepasan tekanan (rare faction) secara bergantian, seperti getaran torak/ piston dalam tabung. Perubahan tekanan yang silih berganti ini menghasilkan bunya yang diterima oleh telinga. Bina Nusantara University

5 Typical Sound Levels LA in dBA Example Threshold of hearing 50
Threshold of hearing 50 Residence 60 Conventional Speech 70 Street Traffic at 100 ft 74 Passing Automobile at 20 ft 80 Light Trucks at 20 ft 120 Loud Rock and Roll Band 140 Jet plane on ground at 20 ft (Adapted from Cantor,1996)

6 Effect of Environmental Noise on People
Interferes with human activities and psychological annoyance sleep disturbance disruption of speech communication disruption of tasks requiring concentration or coordination mental and physical health effects Effects depend on: number of noise events that occur during a time interval peak sound pressure levels reached during the events degree to which peak levels exceed average noise level Make a distinction between “environmental noise” and “occupational noise” Bina Nusantara University

7 Community Reaction to Noise
Several factors (other than magnitude of exposure) influence community reaction to intruding noise: Duration and frequency of occurrence of noise Time of year of noise Time of day of noise Background noise level History of prior exposure to intruding noise Attitude toward the noise source Bina Nusantara University

8 Reported Thresholds for Noise Nuisance
Reported by World Health Organization: at 55 to 60 dBA noise creates annoyance At 60 to 65 dBA annoyance increases considerably At > 65 dBA constrained behaviour patterns Bina Nusantara University

9 Addition of Noise From Several Sources:
Noise doesn’t add linearly! LT = total sound level (dBA) Li = individual component sound level resulting from source i (dBA) Bina Nusantara University

10 Li = individual component sound level during interval i (dBA)
Temporal Aspects Leq: Equivalent Sound Level - energy equivalent sound pressure level averaged over a specific time period (i.e. 24 hrs) used to account for temporal variations in sound Li = individual component sound level during interval i (dBA) fi = time fraction of interval i Bina Nusantara University

11 Ldn: Day-Night Average Sound Level
equivalent to a 24 hr Leq except that 10 dBA weighting penalty is added to noise during nighttime period (22: :00) before computing average Based on studies that have shown people are more disturbed by night-time sound NOTES: - most US suburban areas are currently subject to noise levels greater than this value. Bina Nusantara University

12 Typical Day-Night Noise Levels
Description Typical Range of Ldn, dBA Average Ldn, dBA Quiet suburban residential 48 to 52 50 Normal suburban residential 53 to 57 55 Urban residential 58 to 62 60 Noisy Urban Residential 63 to 67 65 Very noisy urban residential 68 to 72 70 (Adapted from Cantor,1996)

13 r1 = distance from source to nearer pt. (m)
Sound Attenuation Sound pressure level decreases with increasing distance from a source as sound waves radiate outward. For a point source: Example: Construction equipment Sound pressure level decreases by 6 dB for each doubling of distance from a point source r1 = distance from source to nearer pt. (m) r2 = distance from source to farther pt. (m) Bina Nusantara University

14 Sound Attenuation – Line Source
Line source can be treated as a series of point sources: Example: Roadways l1 = distance from source to nearer pt. (m) l2 = distance from source to farther pt. (m) Sound pressure level decreases by 3 dB for each doubling of distance from a line source Bina Nusantara University

15 Minimum Equipment at Site
Estimates of Noise at Construction Sites for Public Works, Roads and Highways Construction Phase All Equipment at Site Minimum Equipment at Site Ground Clearing 84 Excavation 88 78 Foundations Erection 79 Finishing (Adapted from Cantor,1996) Bina Nusantara University