Properties of noise? Kebisingan Industri. Inside NOISE. What is noise? Penyebab kehilangan/gangguan pendengaran adalah: Objective

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1 Kebisingan Industri Objective? Penyebab kehilangan/gangguan pendengaran adalah: Kebisingan industri Luka pada telinga akibat ledakan, shock pukulan pada kepala dan benda asing atau infeksi 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 sebagai akibat fluktuasi tekanan udara terhadap tekanan udara yang stabil. Telinga akan merespons fluktuasi-fluktuasi kecil tersebut dengan sensitivitas yang sangat besar. Bising juga diartikan vibrasi/energy yang dikonduksikan dalam media udara, cairan, padatan, tidak tampak dan dapat memasuki telinga serta menimbulkan sensasi pada alat dengar Properties of noise?

2 Jenis Bising Tergantung pada durasi dan frekuensi Steady 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 riveting Intermitten noise, bising terputus, contoh lalu lintas pesawat Karakteristik bising. Intensitas/tekanan (sound pressure/intensity). Frekuensi. Durasi eksposur terhadap bising Ketiga karakteristik diperlukan karena: Semakin keras suara, semakin tinggi intensitasnya Frekuensi tinggi lebih berbahaya terhadap kemampuan dengar. Telinga manusia lebih sensitif terhadap frekuensi tinggi Semakin lama durasi eksposur semakin besar kerusakan pada mekanisme pendengaran Contoh Intensitas Laju 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 0,000 dyne/cm). B = log (int.terukur/int.acuan) untuk mendapatkan angka yang lebih akurat ditentukan dengan angka kelipatan 0 (desi) Intensity level db=0 Log (IT/IA) Sound pressure level (tekanan bunyi) = 0 log (IT/IA), karena intensitas sebanding dengan kuadrat tekanan bunyi. Tekanan = Sound Pressure Manusia dapar mendengar suara pada tekanan antara 0,000 dynes/cm (ambang dengar/threshold of hearing) sampai 000 dynes/cm range besar sehingga satuan yang dipakai db (decibel): logaritmik Dinyatakan dalam decibel (db) yang dilengkapi skala A, B, dan C sesuai dengan berbagai kegunaan Skala 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 Ruang kelas:?db Rumah Restauran Berbisik Berteriak Jet plane

3 The decibel SOUND INTENSITY SOUND SOURCE Lowest limit of hearing Rustling leaf Quiet farm setting Whisper (5 feet) Dripping faucet, quite office Low conversation, residence Ordinary conversation Idling car Silenced compressor, very noisy restaurant 00,000,000 Backhoe Unsilenced compressor Rock dril, woodworking Pile driver* Rivet gun* Explosive-actuated tool*, jet plane *Intermittent or "impulse" sound LINEAR UNITS Bel 0,000 00,000,000,000 0,000,000,000,000,000 0,000,000,000 00,000,000,000,000,000,000,000 0,000,000,000,000 00,000,000,000,000 Source: Construction Safety Association of Ontario, Hearing Protection for the Construction Industry, 985, page 0 00,000 LOGARITHMIC UNITS Decibel The decibel db = 0 log 0 (I /I 0 ) I = Intensitas db = 0 log 0 (P /P 0 ) P= Tekanan = 0,000 dynes/cm SP (microbar) SPL (db) Ratio Intensitas 0, , Jadi bila SP berubah 0x, maka db bertambah? x Satuan (Konversi) Pressure Sound intensities Pa Bel (B) Decibel (db) Threshold of hearing 0, Quiet office 0,00 0 Ringing alarm clock at m 0, 8 80 Ship's engine room 0 0 Turbo jet engine bar=0 5 Pa=0 5 N/m = dyne/0 cm =0 6 dyne/cm atau microbar = dyne/cm Sumber >.. Sumber >.. (Contoh) db=l=0 log(p /P )=0 log(p /P ) L/0= log(p /P ) 0 L/0 = 0 log(p/p)^ =(P /P ) L=0 log(p /P ) =0 log 0 L/0 (satu sumber) =0 log (Σ0 Li/0 ) =0 log (0 L/0+L/0+ ) =0 log (Σ0 Li/0 ) (banyak sumber) =0 log (0 L/0+L/0+ ) Perbedaan antara sumber bunyi ΣdBA yang turun ditambah ke bunyi terbesar,0,6,,8,5,,0 0,8 0,6 0, 0, 0, 0,

4 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 Hz. Frekuensi Dibagi dalam 8 octaf (octave bands), 7.5, 75, 50, 00, 600, 00, 00, 800, 9600 Hz Telinga manusia bereaksi beda terhadap berbagai frekuensi Kebisingan rata-rata mencakup seluruh taraf kebisingan dari setiap frekuensi dihitung Leq Leq = ekuivalen noise level/ekuivalen energi level Leq = 0 log 0 (Σ 0 Lpi/0 ) 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 dan memutuskan konsentrasi, tidur dan saat istirahat Fisiologis, 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 Mechanics of hearing 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.

5 Mekanisme pendengaran Terdiri dari bagian: telinga luar (daun telinga sampai membran timpani) meneruskan gelombang ke telinga tengah Telinga tengah: membran timpani (yang melekat pada tulang kecil sampai membrana ovale) getaran diteruskan Telinga dalam: tube berspiral seperti rumah siput berisi cairan cairan bervibrasi stimulasi rambut sel impuls syaraf otak Mekanisme pendengaran Pemaparan 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 bising Untuk mengevaluasi akibat pemaparan terhadap kehilangan pendengaran, kenyamanan, interferensi komunikasi dan mengumpulkan informasi untuk pengontrolan. Audiometric test Audiometric test Audiometric test Current OSHA Standards 96.5 Occupational Noise Exposure TABLE D- - PERMISSIBLE NOISE EXPOSURES Duration per day, hours 8 6 / / / or less Sound Level dba slow response

6 Pneumatic chip hammer 0- Crane Jackhammer Concrete joint cutter Skilsaw Hammer Gradeall Front-end loader Stud welder Bulldozer Earth Tamper Backhoe Garbage disposal (at ft.) Vacuum cleaner 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 0-year Working Lifetime (source: NIOSH) Average Exposure 90 dba 9% Average Exposure 85 dba 5% Average Exposure 80 dba % Ketulian = berkurangnya ketajaman pendengaran dibanding/terhadap orang normal (5 db)/ gol usia Ada macam: - permanen: karena penyakit, usia tua, obat, trauma, dan kebisingan - temporer: akibat ekposur bising, dapat pulih setelah istirahat beberapa saat tergantung keparahan Ketulian temporer akan menjadi permanen bila terus terekpos bising (dari rumah, tempat umum, rekreasi, musik, industri, dll.) Secara mekanisme: ketulian ada : - konduktif: peralatan konduksi suara rusak akibat trauma 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. Teenage Girl From the American Academy of Family Physicians website, Rabinowitz article FIGURE. Audiogram findings in the patient in case. The area below the curves represents sound levels that the patient could still hear. (X = left ear; O = right ear) 6

7 Case Study Conclusion Case Study Factory Worker Age 55 "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 Conclusion Carpenter Hearing Losses by Age 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. Pengukuran kebisingan Mengukur overall level sound level meter (satuan dba) Mengukur kebisingan pada setiap level frekuensi SLM dengan frequency analyzer Penentuan eksposur kebisingan pada pekerja noise dosimeter (satuan dba) NOISE KALIBRATOR SOUND LEVEL METER NOISE MEASUREMENT KIT NOISE DOSIMETER 7

8 PENGUKURAN PADA PEKERJA DOSEBADGER Damage risk criteria Variation in individual susceptibility The total energy of the sound The frequency distribution of the sound Other characteristics of the noise exposure, such as whether it is continuous, intermittent, or made up of a series of impacts The total daily time of exposure The length of employment in the noise environment. Noise control A source radiating sound energy A path along which the sound energy travels A receiver such as the human ear Pengendalian kebisingan SUMBER PATHWAY/MEDIA PENERIMA/RECEIVER Cara teknis: SUMBER Substitusi Insulasi sumber PATHWAY Absorpsi/damping Perisai Perpanjang jarak PENERIMA Isolasi pekerja Reduksi waktu APD Pengendalian dilakukan di bagian: SUMBER, RUANG ANTARA sumber dan penerima/pekerja, pada PENERIMA/PEKERJA Urutan pengendalian paling efektif: Kurangi/hilangkan sumber bising Pengendalian pathway: jarak diperjauh dengan perisai/isolator/automatisasi Perlindungan penerima dari bising (APD) 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 8

9 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 control Noise 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 control Noise can often be controlled along the path to the worker with the use of soundabsorbing 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 0 db noise reduction). 9

10 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 direction When encounter walls reflected Total noise exposure within the room = direct + reflected noise Application 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 plugs Properly worn: 5 00 db protection Degree of discomfort :[ employee education is adequate Example. Alat ukur Durasi tingkat bising yang diijinkan dapat dilihat dari tabel di bawah ini: Kebisingan yang terukur di suatu area adalah 90 db selama jam sehari, 97 db selama jam, dan sisa jam berikutnya terdapat variasi tingkat bising secara bergantian 95 db selama 0 menit dan 80 db selama 0 menit. Tentukan apakah tingkat kebisingan yang terukur masih dalam batas yang diijinkan atau tidak. Durasi per hari 8 6,5 ¾ ½ ¼ Tingkat bising Sound level meter, mencatat keseluruhan suara yang dihasilkan tanpa memperhatikan frekuensi yang berhubungan dengan bising total (0-0 d) ( Hz) 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 -00 Hz) 0

11 Faktor-faktor yang mempengaruhi bising Tipe bising: menerus dan terputus Lokasi pekerja Waktu kerja Waktu pemaparan vs db Waktu pemaparan (jam) 8 6,5 0,5 <0,5 (Sumber: FHI) db Kontrol bising Sumber energi suara (modifikasi sumber) Pengaturan media (isolasi/insulasi, perbesar jarak) Penerima (pekerja pada tempat tertutup, pelindung telinga, pengaturan waktu kerja) (Gambar: komponen pengendalian bising) Steps aiming to control noise at work Assess risks to develop a noise control plan Reduce risks for all employees Investigate and implement good practice for control of noise Prioritise noise control measures Use hearing protection for residual risks Carry 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 5-5 db reduction in the noise radiated Cabin internal noise can be reduced by 0- db by applying damping pads and sound barrier mats to floor and engine bulkhead Reduce fan speed by 0% to achieve a noise reduction of 8 db BARRIER-BARIER ATAU PANEL

12 Noise control can be complex ISOLASI PEKERJA/MESIN DI TEMPAT BISING Engage employees in process BAHAN ABSORBER BAHAN BARRIER Use noise control consultants to help solve your problems if complex Hearing protectors Selected for protection, user preference and work activity Guard against over-protection isolation can lead to under-use and safety risks Require information, instruction, training, supervision and motivation Will only protect if worn all the time and properly Rating hearing protectors The sound level conversion (SLC 80 ) 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 70:00 Class and specification of hearing protectors Ear plugs SLC 80 Class May be used up to this noise exposure level Properly fitted Wrongly fitted 0 to 90 db(a) to 7 95 db(a) 8 to 00 db(a) to 5 05 db(a) 6 or greater 5 0 db(a)

13 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 0 db for an exposure time of one hour Wear time 60 minutes 55 minutes 50 minutes 5 minutes Effective attenuation 0 db db 8 db 6 db NAB Kebisingan di lingkungan kerja Kebisingan dari sumber USA (TLV ACGHI) t (eksposur) jam db(a) , ,5 0 <0,5 5 kebisingan impulsif < 0 db INDONESIA Permen 5/999 t dba mnt 97 5 mnt 00 7,5 mnt 0,75 mnt 06,88 mnt 09 dst dilarang > 0 db Decibel yang ditambahkan pada tingkat kebisingan lebih tinggi,5,5 0,5 Perbedaan (db) Tambah pada yg lebih tinggi 0 atau atau Perbedaan antara tingkat bising, db(a) Our challenge Away from Noise assessment as the end point Reliance on hearing protection Towards Control of noise risks through prioritised action plans Introducing equipment with good noise and vibration characteristics Buy Quiet