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Kebisingan Industri

Objective ?

Penyebab kehilangan/gangguanpendengaran adalah:

Kebisingan industriLuka pada telinga akibat ledakan, shock pukulan pada kepala dan benda asing atauinfeksi pada telinga.

Inside NOISE

What is noise?– Definition, energy conducted and sensed, properties:

intensity/pressure, frequency, exposure,

Why unwanted?– Health Effect, age, psychological: annoyed, concentration,

rest/relax problem, communication annoyance, physiological: blood, heart, hearing loss, nausea, muscle control, acoustic trauma (permanent) vs temporary,

Who are susceptible? – Esp. Industrial workers, determining factors: sensitivity,

age,

How to evaluate & control?

What is noise?

Definisi: Suara-suara yang tidak dikehendaki (for Who? Why?)Suara: sensasi yang diterima telinga sebagaiakibat fluktuasi tekanan udara terhadap tekananudara yang stabil. Telinga akan merespons fluktuasi-fluktuasi keciltersebut dengan sensitivitas yang sangat besar.Bising juga diartikan vibrasi/energy yang dikonduksikan dalam media udara, cairan, padatan, tidak tampak dan dapat memasuki telingaserta menimbulkan sensasi pada alat dengar

Properties of noise?

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Jenis BisingTergantung pada durasi dan frekuensiSteady wide band noise, bising yang meliputi suatujelajah frekuensi yang lebar (bising dalam ruangmesin)Steady narrow band noise, bising dari sebagian besarenergi bunyi yang terpusat pada beberapa frekuensisaja, contoh gergaji bundar.Impact noise, kejutan singkat berulang, contohrivetingIntermitten noise, bising terputus, contoh lalu lintaspesawat

Karakteristik bising

1. Intensitas/tekanan (sound pressure/intensity)

2. Frekuensi3. Durasi eksposur terhadap bisingKetiga karakteristik diperlukan karena:

Semakin keras suara, semakin tinggiintensitasnyaFrekuensi tinggi lebih berbahaya terhadapkemampuan dengar. Telinga manusia lebihsensitif terhadap frekuensi tinggiSemakin lama durasi eksposur semakinbesar kerusakan pada mekanismependengaran

Contoh… Intensitas

Laju aliran energi tiap satuan luas yang dinyatakandalam desibell (dB) – Alexander Graham Bell-dB adalah merupakan satuan yang dihasilkan dariperhitungan yang membandingkan suatu tekanansuara yang terukur terhadap suatu tekanan acuan(sebesar 0,0002 dyne/cm2).B = log (int.terukur/int.acuan) untuk mendapatkanangka yang lebih akurat ditentukan dengan angkakelipatan 10 (desi)

Intensity level dB=10 Log (IT/IA)Sound pressure level (tekanan bunyi) = 20 log (IT/IA), karena intensitas sebanding dengan kuadrattekanan bunyi.

Tekanan = Sound PressureManusia dapar mendengar suara padatekanan antara 0,0002 dynes/cm2 (ambangdengar/threshold of hearing) sampai 2000 dynes/cm2 range besar sehingga satuanyang dipakai dB (decibel): logaritmikDinyatakan dalam decibel (dB) yang dilengkapi skala A, B, dan C

sesuai dengan berbagai kegunaanSkala A digunakan karena merupakanresponse yang paling cocok dengan telingamanusia (peka terhadap frekuensi tinggi)Skala B dan C untuk evaluasi kebisinganmesin, dan cocok untuk kebisingan frekuensirendah

Ruang kelas: ?dBRumahRestauranBerbisikBerteriakJet plane

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The decibel

Source: Construction Safety Association of Ontario, Hearing Protection for the Construction Industry, 1985, page 3

*Intermittent or "impulse" sound

14014100,000,000,000,000Explosive-actuated tool*, jet plane1301310,000,000,000,000Rivet gun*120121,000,000,000,000Pile driver*11011100,000,000,000Rock dril, woodworking1001010,000,000,000Unsilenced compressor9091,000,000,000Backhoe808100,000,000Silenced compressor, very noisy restaurant70710,000,000Idling car6061,000,000Ordinary conversation505100,000Low conversation, residence40410,000Dripping faucet, quite office3031,000Whisper (5 feet)202100Quiet farm setting10110Rustling leaf

001Lowest limit of hearing

LOGARITHMIC UNITSDecibel

LINEAR UNITSBel

SOUND SOURCESOUND INTENSITY

The decibel

dB = 10 log10 (I1/I0) I = IntensitasdB = 20 log10 (P1/P0) P= Tekanan = 0,0002

dynes/cm2

SP (microbar) SPL (dB) Ratio Intensitas0,0002 0 100

0,002 20 102

Jadi bila SP berubah 10x, maka dB bertambah ? x

PressurePa Bel (B) Decibel (dB)

Threshold of hearing 0,00002 0 0Quiet office 0,002 4 40Ringing alarm clock at 1 m 0,2 8 80Ship's engine room 20 12 120Turbo jet engine 2000 16 160

Sound intensities

Satuan (Konversi)

1bar=105Pa=105N/m2

=105.105dyne/104cm2

=106dyne/cm2 atau1microbar = 1 dyne/cm2

Sumber > 1…..

dB=L=20 log(P1/P2)=10 log(P1/P2)2

L/10= log(P1/P2)2

10L/10= 10log(P1/P2)^2=(P1/P2)2

L=10 log(P1/P2)2

=10 log 10L/10 (satu sumber)=10 log (Σ10Li/10)=10 log (10L1/10+L2/10+…)

Sumber > 1….. (Contoh)=10 log (Σ10Li/10) (banyak sumber)=10 log

(10L1/10+L2/10+…)

0,1160,2140,3120,4100,680,871,061,251,541,832,122,613,00

ΣdBA yang turunditambah ke

bunyi terbesar

Perbedaanantara sumber

bunyi

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Frekuensi

Adalah jumlah getaran dalam tekanansuara per satuan waktu (Hertz ataucycle per detik), frekuensi dipengaruhiukuran, bentuk dan pergerakansumber, pendengaran normal orangdewasa dapat menangkap bunyi denganfrekuensi 20-15.000 Hz.

Frekuensi

Dibagi dalam 8 octaf (octave bands), 37.5, 75, 150, 300, 600, 1200, 2400, 4800, 9600 HzTelinga manusia bereaksi beda terhadap berbagaifrekuensiKebisingan ‘rata-rata’ mencakup seluruh tarafkebisingan dari setiap frekuensi dihitung LeqLeq = ekuivalen noise level/ekuivalen energi levelLeq = 10 log10 (Σ 10 Lpi/10)

Why unwanted?

Health Effect, age, psychological: annoyed, concentration, rest/relax problem, communication annoyance, physiological: blood, heart, hearing loss, nausea, muscle control, acoustic trauma (permanent) vs temporary,

Efek bising pada manusia

Psikologis, terkejut, mengganggu danmemutuskan konsentrasi, tidur dansaat istirahatFisiologis, seperti menaikkan tekanandarah dan detak jantung, mengurangiketajaman pendengaran, sakit telinga, mual, kendali otot terganggu, dll.Gangguan komunikasi yang mempengaruhi kenyamanan kerjadan keselamatan.

Interference with communication by speech

When background or ambient noise levels are sufficiently high enough, the background noise can mask the sound levels of speech that wish to be heard.

Restaurants can often be classic examples of excessive noise interference due to lack of sufficient quality or quantityof sound absorbing materials that prevent excessive noise buildup. Diners have to speak louder and louder to be heard and in doing so compete with one another, thereby increasing the sound levels to even greater levels. Appropriate acoustical treatment will prevent the reflected noise buildup and significantly reduce the necessity for diners to speak louder toenjoy conversations with one another.

Mechanics of hearing

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Mekanisme pendengaran• Terdiri dari 3 bagian: telinga

luar (daun telinga sampaimembran timpani)

meneruskan gelombang ketelinga tengah

• Telinga tengah: membrantimpani (yang melekat pada 3 tulang kecil sampaimembrana ovale) getaranditeruskan

• Telinga dalam: tube berspiralseperti rumah siput berisicairan cairan bervibrasistimulasi rambut sel impulssyaraf otak

Mekanisme pendengaran

Pemaparan pada suara tinggi danperiode/durasi yang lama akanmenyebabkan sel syaraf pendengar danrambut pada corti over aktif sehinggamenimbulkan kehilangan pendengaranpermanen

Pengukuran bising

Untuk mengevaluasi akibat pemaparanterhadap kehilangan pendengaran, kenyamanan, interferensi komunikasidan mengumpulkan informasi untukpengontrolan.

Audiometric test

Audiometric test Audiometric test

Current OSHA Standards•1926.52 Occupational Noise Exposure

•TABLE D-2 - PERMISSIBLE NOISE EXPOSURES

1151/4 or less

1101/2

1051

1021 1/2

1002

973

954

926

908

Sound Level dBA slow responseDuration per day, hours

6

70Vacuum cleaner 90-96Earth Tamper

80Garbage disposal (at 3 ft.) 93-96Bulldozer

84-93Backhoe101Stud welder 86-94Front-end loader88-102Skilsaw

87-94Gradeall99-102Concrete joint cutter

87-95Hammer102-111Jackhammer

90-96Crane103-113Pneumatic chip hammer

How Does Excessive Noise Damage Your Ears?

Microscopic hair cells of the cochlea are exposed to intense noise over time Hair cells become fatigued and less responsive, losing their ability to recover. Damage becomes permanent resulting in noise-induced permanent threshold shift. Risk of Hearing Loss Estimated Risk of Incurring Material Hearing Impairment as a Function of Average Daily Noise Exposure Over a 40-year Working Lifetime (source: NIOSH)

Average Exposure 90 dBA 29% Average Exposure 85 dBA 15% Average Exposure 80 dBA 3%

Ketulian= berkurangnya ketajaman pendengaran

dibanding/terhadap orang normal (15 dB)/ gol usia• Ada 2 macam:

- permanen: karena penyakit, usia tua, obat, trauma, dankebisingan- temporer: akibat ekposur bising, dapat pulih setelahistirahat beberapa saat tergantung keparahan

• Ketulian temporer akan menjadi permanen bila terusterekpos bising (dari rumah, tempat umum, rekreasi, musik, industri, dll.)

• Secara mekanisme: ketulian ada 2:- konduktif: peralatan konduksi suara rusak akibattrauma atau sakit- sensorinueral: akibat persyarafan pendengaran rusak

What Is The Purpose of Having a Hearing Test on a Regular Basis?

An audiometric testing program is used to track your ability to hear over time. – Baseline and annual

Test records provide the only data that can be used to determine whether the program is preventing noise-induced permanent threshold shifts. It is an integral part of the hearing conservation program. Case Study 1. Teenage Girl From the American Academy of Family Physicians website, Rabinowitz article

FIGURE 1. Audiogram findings in the patient in case 1.

The area below the curves represents sound levels that the patient could still hear. (X = left ear; O = right ear)

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Case Study 1 Conclusion

"Temporary threshold shift" example Common in persons exposed to high noise Represents transient hair cell dysfunction Complete recovery can occur Repeated episodes of such shifts causes permanent threshold shifts because hair cells in the cochlea are progressively lost.

Case Study 2 Factory Worker Age 55

Case Study 2 Conclusion Noise Induced Hearing Loss – Speech discrimination and social function

interference – Difficulty in perceiving and differentiating consonant

sounds – Sounds such as a baby crying or a distant telephone

ringing, may not be heard at all. Tinnitus – Common symptom of noise overexposure – Further interferes with hearing acuity, sleep and

concentration. These impairments have been associated with depression and an increased risk of accidents.

Carpenter Hearing Losses by Age

Pengukuran kebisingan

• Mengukur overall level sound level meter (satuan dBA)

• Mengukur kebisingan pada setiap level frekuensi SLM dengan frequency analyzer

• Penentuan eksposur kebisingan padapekerja noise dosimeter (satuan dBA)

NOISE KALIBRATOR

SOUND LEVEL METER

NOISE MEASUREMENT KIT

NOISE DOSIMETER

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PENGUKURAN PADA PEKERJA

DOSEBADGER

Damage risk criteriaVariation in individual susceptibilityThe total energy of the soundThe frequency distribution of the soundOther characteristics of the noise exposure, such as whether it is continuous, intermittent, or made up of a series of impactsThe total daily time of exposureThe length of employment in the noise environment.

Noise control

A source radiating sound energyA path along which the sound energy travelsA receiver such as the human ear

Pengendalian kebisingan

Pengendalian dilakukan di 3 bagian: SUMBER, RUANG ANTARA sumber dan penerima/pekerja, padaPENERIMA/PEKERJA

Urutan pengendalian paling efektif:• Kurangi/hilangkan sumber bising• Pengendalian pathway: jarak diperjauh dengan

perisai/isolator/automatisasi• Perlindungan penerima dari bising (APD)

SUMBER PATHWAY/MEDIA PENERIMA/RECEIVER

•Cara teknis:

APDPerpanjang jarakReduksi waktuPerisaiInsulasi sumberIsolasi pekerjaAbsorpsi/dampingSubstitusi

PENERIMAPATHWAYSUMBER

•Cara medis:Pemeriksaan ketajaman pendengaran secara periodikPenempatan pekerja sesuai dengan kepekaan thd bisingMonitor ketulian temporer

•Cara manajemen:Reduksi waktu eksposurDiklat pemakaian dan pemeliharaan APD

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Noise control

Source: modification or redesigning of the source.– The modification of compressed air jets for parts

ejection, to reduce noise by altering the jet flow.– Multiple-opening air ejection nozzel: less noise than

single-opening.

Noise controlNoise can be controlled at the source, along the path or at the worker. At the source, equipment may be replaced by quieter models, or less noisy work procedures can be adopted. In general, less friction and vibration mean less noise. Maintenance procedures such as lubrication may sometimes reduce noise by reducing friction. Equipment can sometimes be modified to reduce the amount of noise that is generated. Sound-absorbing material may be attached to the noise source. Or the frequency of the noise may be shifted to one that is less hazardous.

Noise controlNoise can often be controlled along the path to the worker with the use of sound-absorbing paneling on walls or ceilings, and enclosures around noisy machinery. Controls at the worker include both administrative controls and personal protective equipment. – Administrative controls modify how the work

is carried out. – The time employees spend in noisy areas

may be reduced. – Workers in noisy areas may be rotated to

less noisy areas. As the distance from the noise source increases, the pressure (or intensity) of the noise decreases faster than its sound level.

Noise control

Noisy operations may be conducted outside normal working hours to reduce the number of people exposed. Where noise exposures cannot be reduced by other methods, hearing protection is required. This includes ear plugs and ear muffs.

Insulation of the workers

A separate noise insulated room provides effective control (up to 30 dB noise reduction).

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Machine insulation

Machine: on floors and walls vibrate them sound radiation

proper use of machine mountings insulates the machine and reduce the transmission of vibration

Control of noise by absorption

Travels out in all directionWhen encounter walls reflectedTotal noise exposure within the room = direct + reflected noiseApplication of sound absorption material (However, limited: no effect on direct noise).

Reduction of exposure time

Limiting the total daily exposure reduces the noise hazard.See TLV

Personal protection against noise

Many operations cannot be quieted by engineering methods.Therefore protection: ear plugsProperly worn: 25 – 400 dB protectionDegree of discomfort :[ employee education is adequate

Example….

Durasi tingkat bising yang diijinkan dapat dilihat dari tabeldi bawah ini:Kebisingan yang terukur disuatu area adalah 90 dB selama2 jam sehari, 97 dB selama 2 jam, dan sisa 4 jam berikutnya terdapat variasi tingkat bising secara bergantian 95 dB selama 10 menit dan 80 dB selama 10 menit. Tentukan apakah tingkat kebisingan yang terukur masih dalam batas yang diijinkan atau tidak.

90929597100102105107110115

86432

1,51¾½¼

Tingkat bisingDurasi per hari

Alat ukur

Sound level meter, mencatat keseluruhan suarayang dihasilkan tanpa memperhatikanfrekuensi yang berhubungan dengan bisingtotal (30-130 d) – (20-20.000Hz)Sound level meter dengan octave band analyzer, mengukur level bising pada berbagaibatas oktaf di atas range pendengaran manusiadengan mempergunakan filter menurut oktafyang diinginkan (narrow band analyzers untukspektrum sempit 2-200 Hz)

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Faktor-faktor yang mempengaruhibising

Tipe bising: menerus dan terputusLokasi pekerjaWaktu kerja

Waktu pemaparan vs dB

(Sumber: FHI)

909295

100102105110115

8642

1,51

0,5<0,25

dBWaktu pemaparan (jam)

Kontrol bising

Sumber energi suara (modifikasi sumber)Pengaturan media (isolasi/insulasi, perbesar jarak)Penerima (pekerja pada tempat tertutup, pelindungtelinga, pengaturan waktu kerja)

(Gambar: 3 komponen pengendalian bising)

Steps aiming to control noise at work

Assess risks to develop a noise control planReduce risks for all employeesInvestigate and implement good practice for control of noise Prioritise noise control measures Use hearing protection for residual risksCarry out a noise dosimetry program to check the effectiveness of noise control measures

Some simple noise control techniques

Application of damping material to chutes, hoppers, machine guards etc., can give a 5-25 dB reduction in the noise radiatedCabin internal noise can be reduced by 10-12 dB by applying damping pads and sound barrier mats to floor and engine bulkheadReduce fan speed by 30% to achieve a noise reduction of 8 dB

BARRIER-BARIER ATAU PANEL

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ISOLASI PEKERJA/MESIN DI TEMPAT BISING

BAHAN ABSORBER BAHAN BARRIER

Noise control can be complex

Use noise control consultants to help solve your problems if complex

Engage employees in process

Hearing protectorsSelected for protection, user preference and work activityGuard against over-protection — isolation can lead to under-use and safety risksRequire information, instruction, training, supervision and motivationWill only protect if worn all the time and properly

Rating hearing protectors

The sound level conversion (SLC80 ) rating of a hearing protector, ear plugs or headset is a simple number and class rating that is derived from a test procedure as outlined in the Australian/New Zealand Standard AS/NZS 1270:2002

Class and specification of hearing protectors

110 dB(A)526 or greater

105 dB(A)422 to 25

100 dB(A)318 to 21

95 dB(A)214 to 17

90 dB(A)110 to 13

May be used up to this noise exposure levelClassSLC80

Ear plugs

Properly fitted Wrongly fitted

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Ear muffs

Proper clamping force Worn-out head band

Reduction in protection provided by hearing protectors with decreased wearing time

Example: Effectiveness of wearing an ear muff with a rating of 30 dB for an exposure time of one hour

6 dB45 minutes

8 dB50 minutes

11 dB55 minutes

30 dB60 minutes

Effective attenuationWear time

NAB Kebisingan di lingkungan kerja

USA (TLV ACGHI)t (eksposur) jam dB(A)

8 906 924 953 972 100

1,5 1021 105

0,5 110<0,25 115

kebisingan impulsif < 140 dB

t dBA8 854 882 911 94

30 mnt 9715 mnt 1007,5 mnt 103

3,75 mnt 1061,88 mnt 109

dstdilarang > 140 dB

INDONESIA Permen 51/1999

Kebisingan dari 2 sumber

14Perbedaan antara 2 tingkat bising, dB(A)

3

2,5

12108642

0,5

1,5

2

1

Dec

ibel

yan

g di

tam

bahk

anpa

datin

gkat

kebi

sing

anle

bih

tingg

i

010+

14 – 9

22 atau 3

30 atau 1

Tambah pada yg lebihtinggi

Perbedaan (dB)

Our challengeAway from …

Noise assessment as the end pointReliance on hearing protection

Towards …Control of noise risks through prioritised action plansIntroducing equipment with good noise and vibration characteristics – ‘Buy Quiet’