Kebisingan Industri

Definisi dan pengertianBising = suara-suara yang tidak dikehendakiDefinisi secara ilmiah = sensasi yang diterima telinga sebagai akibat fluktuasi tekanan udara superimposing tekanan atmosfir/udara yang steadyBising = sejenis vibrasi/energi yang dikonduksikan dalam media udara, cairan, padatan, tidak tampak, dan dapat memasuki telinga serta menimbulkan sensasi pada alat dengar

What is noise?

Definisi: Suara-suara yang tidak dikehendaki (for Who? Why?)Suara: sensasi yang diterima telinga sebagai akibat fluktuasi tekanan udara terhadap tekanan udara yang stabil. Telinga akan merespons fluktuasi-fluktuasi kecil tersebut dengan sensitivitas yang sangat besar.

Properties of noise?

Karakteristik bisingIntensitas/tekanan (sound pressure/intensity)FrekuensiDurasi eksposur terhadap bisingKetiga karakteristik diperlukan karena:Semakin keras suara, semakin tinggi intensitasnyaFrekuensi tinggi lebih berbahaya terhadap kemampuan dengar. Telinga manusia lebih sensitif terhadap frekuensi tinggiSemakin lama durasi eksposur semakin besar kerusakan pada mekanisme pendengaran

Jenis BisingTergantung pada durasi dan frekuensiSteady wide band noise, bising yang meliputi suatu jelajah frekuensi yang lebar (bising dalam ruang mesin)Steady narrow band noise, bising dari sebagian besar energi bunyi yang terpusat pada beberapa frekuensi saja, contoh gergaji bundar.Impact noise, kejutan singkat berulang, contoh rivetingIntermitten noise, bising terputus, contoh lalu lintas pesawat

Contoh

Tekanan = Sound PressureManusia dapar mendengar suara pada tekanan antara 0,0002 dynes/cm2 (ambang dengar/threshold of hearing) sampai 2000 dynes/cm2 range besar sehingga satuan yang dipakai dB (decibel): logaritmikDinyatakan dalam decibel (dB) yang dilengkapi skala A, B, dan C sesuai dengan berbagai kegunaanSkala A digunakan karena merupakan response yang paling cocok dengan telinga manusia (peka terhadap frekuensi tinggi)Skala B dan C untuk evaluasi kebisingan mesin, dan cocok untuk kebisingan frekuensi rendah

IntensitasLaju aliran energi tiap satuan luas yang dinyatakan dalam desibell (dB) Alexander Graham Bell-dB adalah merupakan satuan yang dihasilkan dari perhitungan yang membandingkan suatu tekanan suara yang terukur terhadap suatu tekanan acuan (sebesar 0,0002 dyne/cm2).B = log (int.terukur/int.acuan) untuk mendapatkan angka yang lebih akurat ditentukan dengan angka kelipatan 10 (desi)

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

Ruang kelas: ?dB Rumah Restauran Berbisik Berteriak Jet plane

The decibel

SOUND INTENSITYSOUND SOURCELINEAR UNITS BelLOGARITHMIC UNITS DecibelLowest limit of hearing1 0 0Rustling leaf10 1 10Quiet farm setting100 2 20Whisper (5 feet)1,000 3 30Dripping faucet, quite office10,000 4 40Low conversation, residence100,000 5 50Ordinary conversation1,000,000 6 60Idling car10,000,000 7 70Silenced compressor, very noisy restaurant100,000,000 8 80Backhoe1,000,000,000 9 90Unsilenced compressor10,000,000,00010100Rock dril, woodworking100,000,000,00011110Pile driver*1,000,000,000,00012120Rivet gun*10,000,000,000,00013130Explosive-actuated tool*, jet plane100,000,000,000,00014140*Intermittent or "impulse" soundSource: Construction Safety Association of Ontario, Hearing Protection for the Construction Industry, 1985, page 3

The decibel dB = 10 log10 (I1/I0) I = Intensitas dB = 20 log10 (P1/P0) P= Tekanan = 0,0002 dynes/cm2

SP (microbar) SPL (dB)Ratio Intensitas0,0002 0 1000,002 20 102

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

Sheet1

PressureSound intensities

PaBel (B)Decibel (dB)

Threshold of hearing0.0000200

Quiet office0.002440

Ringing alarm clock at 1 m0.2880

Ship's engine room2012120

Turbo jet engine200016160

Sheet2

Sheet3

Frekuensi Adalah jumlah getaran dalam tekanan suara per satuan waktu (Hertz atau cycle per detik), frekuensi dipengaruhi ukuran, bentuk dan pergerakan sumber, pendengaran normal orang dewasa dapat menangkap bunyi dengan frekuensi 20-15.000 Hz.

FrekuensiDibagi dalam 8 octaf (octave bands), 37.5, 75, 150, 300, 600, 1200, 2400, 4800, 9600 HzTelinga manusia bereaksi beda terhadap berbagai frekuensiKebisingan rata-rata mencakup seluruh taraf kebisingan dari setiap frekuensi dihitung LeqLeq = ekuivalen noise level/ekuivalen energi levelLeq = 10 log10 ( 10 Lpi/10)

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)2L/10= log(P1/P2)210L/10= 10log(P1/P2)^2=(P1/P2)2

L=10 log(P1/P2)2 =10 log 10L/10 (satu sumber)L =10 log (10Li/10) (sumber banyak) =10 log (10L1/10+ 10L2/10+)

Sumber > 1.. (Contoh)=10 log (10Li/10) (banyak sumber) =10 log (10L1/10+ 10L2/10+)

Perbedaan antara sumber bunyidBA yang turun ditambah ke bunyi terbesar03,012,622,131,841,551,261,070,880,6100,4120,3140,2160,1

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)2L/10= log(P1/P2)210L/10= 10log(P1/P2)^2=(P1/P2)2

L=10 log(P1/P2)2 =10 log 10L/10 (satu sumber)L =10 log (10Li/10) (sumber banyak) =10 log (10L1/10+ 10L2/10+)

Sumber > 1.. (Contoh)=10 log (10Li/10) (banyak sumber) =10 log (10L1/10+ 10L2/10+)

Perbedaan antara sumber bunyidBA yang turun ditambah ke bunyi terbesar03,012,622,131,841,551,261,070,880,6100,4120,3140,2160,1

Kebisingan dari 2 sumber

Perbedaan (dB)Tambah pada yg lebih tinggi0 atau 132 atau 324 9110+0

Efek bising pada manusiaPsikologis, terkejut, mengganggu dan memutuskan konsentrasi, tidur dan saat istirahatFisiologis, seperti menaikkan tekanan darah dan detak jantung, mengurangi ketajaman pendengaran, sakit telinga, mual, kendali otot terganggu, dll.Gangguan komunikasi yang mempengaruhi kenyamanan kerja dan 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 quantity of 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 to enjoy conversations with one another.

Mechanics of hearing

Mekanisme pendengaran

Terdiri dari 3 bagian: telinga luar (daun telinga sampai membran timpani) meneruskan gelombang ke telinga tengahTelinga tengah: membran timpani (yang melekat pada 3 tulang kecil sampai membrana ovale) getaran diteruskanTelinga dalam: tube berspiral seperti rumah siput berisi cairan cairan bervibrasi stimulasi rambut sel impuls syaraf otak

Gangguan pendengaranPemaparan pada suara tinggi dan periode/durasi yang lama akan menyebabkan sel syaraf pendengar dan rambut pada corti over aktif sehingga menimbulkan kehilangan pendengaran permanen

Pengukuran kebisingan

Mengukur overall level sound level meter (satuan dBA)Mengukur kebisingan pada setiap level frekuensi SLM dengan frequency analyzerPenentuan eksposur kebisingan pada pekerja noise dosimeter (satuan dBA)

Alat ukurSound level meter, mencatat keseluruhan suara yang dihasilkan tanpa memperhatikan frekuensi yang berhubungan dengan bising total (30-130 d) (20-20.000Hz)Sound level meter dengan octave band analyzer, mengukur level bising pada berbagai batas oktaf di atas range pendengaran manusia dengan mempergunakan filter menurut oktaf yang diinginkan (narrow band analyzers untuk spektrum sempit 2-200 Hz)

NOISE KALIBRATORSOUND LEVEL METERNOISE MEASUREMENT KITNOISE DOSIMETER

PENGUKURAN PADA PEKERJADOSEBADGER

Construction Noise Levels

Pneumatic chip hammer 103-113Crane90-96Jackhammer 102-111Hammer87-95Concrete joint cutter 99-102Gradeall87-94Skilsaw 88-102Front-end loader86-94Stud welder 101Backhoe84-93Bulldozer 93-96Garbage disposal (at 3 ft.) 80Earth Tamper 90-96Vacuum cleaner 70

Construction Noise Levels

Pengukuran akibat bisingUntuk mengevaluasi akibat pemaparan terhadap kehilangan pendengaran, kenyamanan, interferensi komunikasi dan mengumpulkan informasi untuk pengontrolan.

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 usiaAda 2 macam: - permanen: karena penyakit, usia tua, obat, trauma, dan kebisingan- temporer: akibat ekposur bising, dapat pulih setelah istirahat beberapa saat tergantung keparahanKetulian temporer akan menjadi permanen bila terus terekpos bising (dari rumah, tempat umum, rekreasi, musik, industri, dll.)Secara mekanisme: ketulian ada 2:- konduktif: peralatan konduksi suara rusak akibat trauma atau sakit- sensorinueral: akibat persyarafan pendengaran rusak

Audiometric test

Audiometric test

Audiometric testCurrent OSHA Standards 1926.52 Occupational Noise Exposure TABLE D-2 - PERMISSIBLE NOISE EXPOSURES

Duration per day, hoursSound Level dBA slow response89069249539721001 1/210211051/21101/4 or less115

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)

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

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 controlA 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, pada PENERIMA/PEKERJAUrutan pengendalian paling efektif:Kurangi/hilangkan sumber bisingPengendalian pathway: jarak diperjauh dengan perisai/isolator/automatisasiPerlindungan penerima dari bising (APD)

SUMBER

PATHWAY/MEDIA

PENERIMA/RECEIVER

Cara teknis:

Cara medis: Pemeriksaan ketajaman pendengaran secara periodik Penempatan pekerja sesuai dengan kepekaan thd bising Monitor ketulian temporer

Cara manajemen: Reduksi waktu eksposur Diklat pemakaian dan pemeliharaan APD

Noise controlSource: 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 controlNoisy 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 workersA separate noise insulated room provides effective control (up to 30 dB noise reduction).

Machine insulationMachine: on floors and walls vibrate themsound radiation proper use of machine mountings insulates the machine and reduce the transmission of vibration

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

Reduction of exposure timeLimiting the total daily exposure reduces the noise hazard.See TLV

Personal protection against noiseMany 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 tabel di bawah ini:Kebisingan yang terukur di suatu area adalah 90 dB selama 2 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.

Durasi per hariTingkat bising864321,5190929597100102105107110115

Faktor-faktor yang mempengaruhi bisingTipe bising: menerus dan terputusLokasi pekerjaWaktu kerja

NAB Kebisingan di lingkungan kerjaUSA (TLV ACGHI)

INDONESIA Permen 51/1999

Sheet1

t (eksposur) jamdB(A)

890

692

495

397

2100

1.5102

1105

0.5110

Waktu pemaparan vs dB (TLV)

Waktu pemaparan (jam)dB86421,510,5

Steps aiming to control noise at workAssess 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 techniquesApplication 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

ISOLASI PEKERJA/MESIN DI TEMPAT BISINGBAHAN ABSORBERBAHAN BARRIER

Noise control can be complexUse noise control consultants to help solve your problems if complexEngage 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 protectorsThe 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

SLC80ClassMay be used up to this noise exposure level10 to 13190 dB(A)14 to 17295 dB(A)18 to 213100 dB(A)22 to 254105 dB(A)26 or greater5110 dB(A)

Ear plugs Properly fittedWrongly fitted

Ear muffs Proper clamping forceWorn-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

Wear timeEffective attenuation60 minutes30 dB55 minutes11 dB50 minutes8 dB45 minutes6 dB

Our challengeAway from Noise assessment as the end pointReliance on hearing protectionTowards Control of noise risks through prioritised action plansIntroducing equipment with good noise and vibration characteristics Buy Quiet

TWA untuk kebisingan: berdasarkan standar kebisingan. STANDAR KEBISINGAN

Jumlah jamdB(A)1,51021,01050,751070,51100,25115

Jumlah jamdB(A)8906924953972100

dB(A)809095971001T ukur2 jam4 jam2 jamT TLVtt8 jam4 jam3 jamTWA04/82/4= 1 < batas aman2T ukur02 jam2 jam2 jamT TLVtt8 jam4 jam3 jamTWA02/82/42/3= 17/12 >batas aman

Noise3. 4 orang pekerja printer di unit percetakan dimana terdapatoffset press. Masing-masing terpapar sbb:

Berapa dosis harian yang diterimanya? dan Equivalent 8-hour Sound Pressure Level (SPL) yang dialami pekerja percetakan tersebut?

No. of presses operatingAverage Sound Pressure Level (dBA)Average daily time in operation (hours)081 4.5 1932.12961.03980.4

Jawab:

= 27.858 jamUntuk SPL 81 dBA:= 5.278 jamUntuk SPL 93 dBA: = 3.482 jamUntuk SPL 96 dBA:= 2.639 jamUntuk SPL 98 dBA:

Noise= 0.998Now, expressing this result as a percentage as required by the problem statement, we have: Dprinter= 99.8%The Printing Company that employs these four Printers is not in violation of any established OSHA SPL dosage standards.

NoiseLequivalent = 90 + 16.61 log[D]

Lequivalent = 90 + 16.61 log[0.998] = 89.987 ~ 90 dBA

These Printers experience an equivalent SPL of ~ 90 dBA

Noise4. How much longer is an individual, without hearing protection, permitted to work at a location where the noise level has just been reduced from 104 dBA to 92 dBA?

To answer this question, we must first determine the OSHA permitted duration, in hours, for each of the two identified noise levels.Tmax = 8 / [2(L-90)/5]For an SPL of 104 dBA: Tmax @ 104 dBA= 8 / [2(104-90)/5] = 1.149 hoursFor an SPL of 92 dBA: Tmax @ 92 dBA= 8 / [2(92-90)/5] = 6.063 hoursThe additional time permitted at the lesser noise level of 92 dBA, Tmax, is simply the difference between these two OSHA permitted time intervals; thus:Tmax=6.063 1.149 = 4.914 hoursThis individual can spend an additional 4.9 hours at a 92 dBA noise level

*Ensure people are properly trained in the correct fitting of ear plugsPeoples ears are different. Is there sufficient variety of ear plugs provided to suit different ear canals and different job requirements? One size (and type) may not fit all, and comfort and effectiveness are important considerations to ensure compliance.*Ear muffs left in the up position on hard hats may also lose their clamping force and the pads become compressed*Sound attenuation = The reduction in the intensity or in the sound pressure level of sound which is transmitted from one point to anotherEffective attenuation = how well do the protectors do their job?If worn correctly for the full one hour then the attenuation (or decrease in sound energy) is 30 dB, as per the rating.But if taken off for a total of 5 minutes in that hour (e.g. to listen to someone speaking, rub ear), the effective attenuation is actually 11 dB and not 30 dB (remembering that the scale is logarithmic and 20 dB is 100 times the sound energy)!