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

Kebisingan Industri

Objective

?

Penyebab kehilangan/gangguan

pendengaran adalah:

zKebisingan industri

zLuka pada telinga akibat ledakan, shock pukulan pada kepala dan benda asing atau infeksi pada telinga.

Inside NOISE

z

What is noise?

–Definition, energy conducted and sensed, properties: intensity/pressure, frequency, exposure,

z

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,

z

Who are susceptible?

–Esp. Industrial workers, determining factors: sensitivity, age,

z

How to evaluate & control?

What is noise?

Definisi:

zSuara-suara yang tidak dikehendaki (for Who?

Why?)

zSuara: sensasi yang diterima telinga sebagai akibat fluktuasi tekanan udara terhadap tekanan udara yang stabil.

zTelinga akan merespons fluktuasi-fluktuasi kecil tersebut dengan sensitivitas yang sangat besar.

zBising juga diartikan vibrasi/energy yang dikonduksikan dalam media udara, cairan, padatan, tidak tampak dan dapat memasuki telinga serta menimbulkan sensasi pada alat dengar

Jenis Bising

zTergantung pada durasi dan frekuensi

zSteady wide band noise, bising yang meliputi suatu jelajah frekuensi yang lebar (bising dalam ruang mesin)

zSteady narrow band noise, bising dari sebagian besar energi bunyi yang terpusat pada beberapa frekuensi saja, contoh gergaji bundar.

zImpact noise, kejutan singkat berulang, contoh riveting

zIntermitten noise, bising terputus, contoh lalu lintas pesawat

Karakteristik bising

1. Intensitas/tekanan (sound pressure/intensity)

2. Frekuensi

3. Durasi eksposur terhadap bising Ketiga karakteristik diperlukan karena: z Semakin keras suara, semakin tinggi

intensitasnya

z Frekuensi tinggi lebih berbahaya terhadap kemampuan dengar. Telinga manusia lebih sensitif terhadap frekuensi tinggi

z Semakin lama durasi eksposur semakin besar kerusakan pada mekanisme pendengaran

Contoh…

Intensitas

zLaju aliran energi tiap satuan luas yang dinyatakan dalam desibell (dB) – Alexander Graham

Bell-zdB adalah merupakan satuan yang dihasilkan dari perhitungan yang membandingkan suatu tekanan suara yang terukur terhadap suatu tekanan acuan (sebesar 0,0002 dyne/cm2).

zB = log (int.terukur/int.acuan) untuk mendapatkan angka yang lebih akurat ditentukan dengan angka kelipatan 10 (desi)

zIntensity level dB=10 Log (IT/IA)

zSound pressure level (tekanan bunyi) = 20 log (IT/IA), karena intensitas sebanding dengan kuadrat tekanan bunyi.

Tekanan = Sound Pressure

zManusia dapar mendengar suara pada

tekanan antara 0,0002 dynes/cm2 (ambang dengar/threshold of hearing) sampai 2000 dynes/cm2 Æ range besar sehingga satuan yang dipakai dB (decibel): logaritmik zDinyatakan dalam decibel (dB) yang

dilengkapi skala A, B, dan C

Æsesuai dengan berbagai kegunaan zSkala A digunakan karena merupakan

response yang paling cocok dengan telinga manusia (peka terhadap frekuensi tinggi) zSkala B dan C untuk evaluasi kebisingan

mesin, dan cocok untuk kebisingan frekuensi rendah

z

Ruang kelas:

?dB

z

Rumah

z

Restauran

z

Berbisik

z

Berteriak

z

Jet plane

The decibel

z

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

*Intermittent or "impulse" sound

140 14 100,000,000,000,000 Explosive-actuated tool*, jet plane

130 13 10,000,000,000,000 Rivet gun* 120 12 1,000,000,000,000 Pile driver* 110 11 100,000,000,000

Rock dril, woodworking

100 10 10,000,000,000 Unsilenced compressor 90 9 1,000,000,000 Backhoe 80 8 100,000,000

Silenced compressor, very noisy restaurant

70 7 10,000,000 Idling car 60 6 1,000,000 Ordinary conversation 50 5 100,000

Low conversation, residence

40 4 10,000

Dripping faucet, quite office

30 3 1,000 Whisper (5 feet) 20 2 100

Quiet farm setting

10 1 10 Rustling leaf 0 0 1

Lowest limit of hearing

LOGARITHMIC UNITS Decibel LINEAR UNITS Bel SOUND SOURCE SOUND INTENSITY

The decibel

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

SP (microbar) SPL (dB) Ratio Intensitas

0,0002 0 100

0,002 20 102

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

Pressure

Pa Bel (B) Decibel (dB)

Threshold of hearing 0,00002 0 0

Quiet office 0,002 4 40

Ringing alarm clock at 1 m 0,2 8 80

Ship's engine room 20 12 120

Turbo jet engine 2000 16 160

Sound intensities

Satuan (Konversi)

z

1bar=10

5

_Pa=10

5

_N/m

2

z

=10

5

_.10

5

_dyne/10

4

_cm

2

z

=10

6

_dyne/cm

2

_atau

z

1microbar = 1 dyne/cm

2

Sumber > 1…..

z

dB=L=20 log(P

₁

/P

₂

)=10 log(P

₁

/P

₂

)

2

z

L/10= log(P

₁

/P

₂

)

2

z

10

L/10

_{= 10}

log(P1/P2)^2

_=(P

1

/P

2

)

2

z

L=10 log(P

₁

/P

₂

)

2

z

=10 log 10

L/10

_{(satu sumber)}

z

=10 log (Σ10

Li/10

₎

z

=10 log (10

L1/10+L2/10+…

₎

Sumber > 1….. (Contoh)

z=10 log (Σ10Li/10₎ (banyak sumber) z =10 log (10L1/10+L2/10+…₎ 0,1 16 0,2 14 0,3 12 0,4 10 0,6 8 0,8 7 1,0 6 1,2 5 1,5 4 1,8 3 2,1 2 2,6 1 3,0 0

ΣdBA yang turun ditambah ke bunyi terbesar Perbedaan

antara sumber bunyi

Frekuensi

z

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.

Frekuensi

zDibagi dalam 8 octaf (octave bands), 37.5, 75, 150, 300, 600, 1200, 2400, 4800, 9600 Hz

zTelinga manusia bereaksi beda terhadap berbagai frekuensi

zKebisingan ‘rata-rata’ mencakup seluruh taraf kebisingan dari setiap frekuensi Æ dihitung Leq Leq = ekuivalen noise level/ekuivalen energi level Leq = 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

z

Psikologis, terkejut, mengganggu dan

memutuskan konsentrasi, tidur dan

saat istirahat

z

Fisiologis, seperti menaikkan tekanan

darah dan detak jantung, mengurangi

ketajaman pendengaran, sakit telinga,

mual, kendali otot terganggu, dll.

z

Gangguan komunikasi yang

mempengaruhi kenyamanan kerja

dan keselamatan.

Interference with communication by speech

z 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.

z 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.

z 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) Æmeneruskan gelombang ke telinga tengah

• Telinga tengah: membran timpani (yang melekat pada 3 tulang kecil sampai membrana ovale) Æ getaran diteruskan

• Telinga dalam: tube berspiral seperti rumah siput berisi cairanÆ cairan bervibrasi Æ stimulasi rambut selÆ impuls syaraf otak

Mekanisme pendengaran

z

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

z

Audiometric test

z

Audiometric test

z

Current OSHA Standards •1926.52 Occupational Noise Exposure

•TABLE D-2 - PERMISSIBLE NOISE EXPOSURES

115 1/4 or less 110 1/2 105 1 102 1 1/2 100 2 97 3 95 4 92 6 90 8

Sound Level dBA slow response Duration per day, hours

70 Vacuum cleaner 90-96 Earth Tamper 80 Garbage disposal (at 3 ft.) 93-96 Bulldozer 84-93 Backhoe 101 Stud welder 86-94 Front-end loader 88-102 Skilsaw 87-94 Gradeall 99-102 Concrete joint cutter 87-95 Hammer 102-111 Jackhammer 90-96 Crane 103-113 Pneumatic chip hammer z

How Does Excessive Noise

Damage Your Ears?

z Microscopic hair cells of the cochlea are exposed to intense noise over time

z Hair cells become fatigued and less responsive, losing their ability to recover.

z Damage becomes permanent resulting in noise-induced permanent threshold shift.

z Risk of Hearing Loss

z Estimated Risk of Incurring Material Hearing Impairment as a Function of Average Daily Noise Exposure Over a 40-year Working Lifetime (source: NIOSH)

z Average Exposure 90 dBA 29% z Average Exposure 85 dBA 15% z 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, 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 2:

- 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?

z

zAn audiometric testing program is used to track your ability to hear over time.

–Baseline and annual

zTest 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.

zCase 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

z"Temporary threshold shift" example

zCommon in persons exposed to high

noise

zRepresents transient hair cell dysfunction

zComplete recovery can occur zRepeated 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

zNoise 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.

zTinnitus

–Common symptom of noise overexposure –Further interferes with hearing acuity, sleep and

concentration.

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

Carpenter Hearing Losses by Age

Pengukuran kebisingan

• Mengukur overall level Æ sound level

meter (satuan dBA)

• Mengukur kebisingan pada setiap level

frekuensi

Æ SLM dengan frequency

analyzer

• Penentuan eksposur kebisingan pada

pekerja

Æ noise dosimeter (satuan dBA)

NOISE KALIBRATOR SOUND LEVEL METER NOISE MEASUREMENT KIT NOISE DOSIMETER

PENGUKURAN PADA

PEKERJA DOSEBADGER

Damage risk criteria

zVariation in individual susceptibility zThe total energy of the sound

zThe frequency distribution of the sound zOther characteristics of the noise

exposure, such as whether it is

continuous, intermittent, or made up of a series of impacts

zThe total daily time of exposure zThe length of employment in the noise

environment.

Noise control

z

A source radiating sound energy

z

A path along which the sound

energy travels

z

A receiver such as the human ear

Pengendalian kebisingan

Pengendalian dilakukan di 3 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)

SUMBER PATHW AY/MEDIA PENERIMA/RECEIVER

•Cara teknis: APD Perpanjang jarak Reduksi waktu Perisai Insulasi sumber Isolasi pekerja Absorpsi/damping Substitusi PENERIMA PATHWAY SUMBER •Cara medis:

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

•Cara manajemen: Reduksi waktu eksposur

Noise control

z

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

zNoise 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

lubricationmay sometimes reduce noise by reducing friction. Equipment can sometimes be modified to reduce the amount of noise that is generated. Sound-absorbing materialmay be attached to the noise source. Or the frequency of the noise may be shifted to one that is less hazardous.

Noise control

zNoise can often be controlled along the pathto the worker with the use of sound-absorbing paneling on walls or ceilings, and enclosures around noisy machinery. zControls 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

z

Noisy operations may be conducted

outside normal working hours to

reduce the number of people

exposed.

z

Where noise exposures cannot be

reduced by other methods, hearing

protection is required. This

includes ear plugs and ear muffs.

Insulation of the workers

z

A separate noise insulated room

provides effective control (up to 30

dB noise reduction).

Machine insulation

z

Machine: on floors and walls

Æ

vibrate themÆsound radiation

proper use of machine mountings

insulates the machine and reduce

the transmission of vibration

Control of noise by absorption

z

Travels out in all direction

z

When encounter wallsÆreflected

z

Total noise exposure within the

room =

direct

+ reflected noise

z

Application of sound absorption

material (However, limited: no

effect on direct noise).

Reduction of exposure time

z

Limiting the total daily exposure

reduces the noise hazard.

z

See TLV

Personal protection against noise

z

Many operations cannot be quieted

by engineering methods.

z

Therefore Æ protection: ear plugs

z

Properly worn: 25 – 400 dB

protection

z

Degree of discomfort :[ Æ employee

education is adequate

Example….

z Durasi tingkat bising yang diijinkan dapat dilihat dari tabel di bawah ini:

z 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. 90 92 95 97 100 102 105 107 110 115 8 6 4 3 2 1,5 1 ¾ ½ ¼ Tingkat bising Durasi per hari

Alat ukur

zSound level meter, mencatat keseluruhan suara yang dihasilkan tanpa memperhatikan frekuensi yang berhubungan dengan bising total (30-130 d) – (20-20.000Hz)

zSound 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)

Faktor-faktor yang mempengaruhi

bising

z

Tipe bising: menerus dan terputus

z

Lokasi pekerja

z

Waktu kerja

Waktu pemaparan vs dB

(Sumber: FHI) 90 92 95 100 102 105 110 115 8 6 4 2 1,5 1 0,5 <0,25 dB Waktu pemaparan (jam)

Kontrol bising

zSumber energi suara (modifikasi sumber) zPengaturan media (isolasi/insulasi, perbesar jarak) zPenerima (pekerja pada tempat tertutup, pelindung

telinga, pengaturan waktu kerja)

(Gambar: 3 komponen pengendalian bising)

Steps aiming to control noise at

work

zAssess risks to develop a noise control plan

zReduce risks for all employees

zInvestigate and implement good practice for control of noise

zPrioritise noise control measures zUse hearing protection for residual risks zCarry out a noise dosimetry program to check the effectiveness of noise control measures

Some simple noise control

techniques

zApplication of damping material to chutes, hoppers, machine guards etc., can give a 5-25 dB reduction in the noise radiated

zCabin internal noise can be reduced by 10-12 dB by applying damping pads and sound barrier mats to floor and engine bulkhead

zReduce fan speed by 30% to achieve a noise reduction of 8 dB

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 protectors

zSelected for protection, user preference and work activity

zGuard against over-protection — isolation can lead to under-use and safety risks zRequire information, instruction,

training, supervision and motivation zWill 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) 5 26 or greater 105 dB(A) 4 22 to 25 100 dB(A) 3 18 to 21 95 dB(A) 2 14 to 17 90 dB(A) 1 10 to 13

May be used up to this noise exposure level Class

SLC₈₀

Ear plugs

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 dB 45 minutes 8 dB 50 minutes 11 dB 55 minutes 30 dB 60 minutes Effective attenuation Wear time

NAB Kebisingan di lingkungan kerja

USA (TLV ACGHI)

t (eksposur) jam dB(A)

8 90 6 92 4 95 3 97 2 100 1,5 102 1 105 0,5 110 <0,25 115 kebisingan impulsif < 140 dB t dBA 8 85 4 88 2 91 1 94 30 mnt 97 15 mnt 100 7,5 mnt 103 3,75 mnt 106 1,88 mnt 109 dst dilarang > 140 dB INDONESIA Permen 51/1999

Kebisingan dari 2 sumber

14 Perbedaan antara 2 tingkat bising, dB(A) 3 2,5 12 10 8 6 4 2 0,5 1,5 2 1 D e ci bel y ang di ta m bahkan pad a ti ng kat k ebi si ng an le bi h ti n g g i 0 10+ 1 4 – 9 2 2 atau 3 3 0 atau 1

Tambah pada yg lebih tinggi Perbedaan (dB)

Our challenge

Away from …

zNoise assessment as the end point zReliance on hearing protection

Towards …

zControl of noise risks through prioritised action plans

zIntroducing equipment with good noise and vibration characteristics – ‘Buy Quiet’