bahan kuliah k3 pertemuan 2

8/10/2019 Bahan Kuliah K3 Pertemuan 2

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A human being is not only a body or a combination

of organs, but also a living unit, both body and soul

(conscience), and a social being that interactsactively with his or her environment.

It is a complex biological machine that has just

acquired new insights about the way the worldworks.

Physical and mental processes have remained

largely unchanged while the environment created by

us has changed from the primitive Stone Age

existence to one of modern technology and control.


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The acquisition of this new technology broughtabout new diseases as result of our new

discoveries.

How we are killing ourselves:

(i) by our own careless habits;

(ii) by carelessly polluting the environment; and(iii) by permitting social conditions to persist -conditions like poverty, hunger and ignorance -which destroy health especially for infants and

children (The Surgeon General of the UnitedStates Federal Health Service)


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Definitions of Occupational Disease

Occupational diseases stand at one end of

the spectrum of work relatedness where

the relationship to specific causative

factors at work has been fully established

and the factors concerned can be

identified, measured, and eventually

controlled (WHO, 1985).


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Three main factors which influence our

health and well being, as well as ourcapacity to work as well as our life

expectancy are:

hereditary factors

external factors

processes of ageing


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Work related diseases may be partially

caused by adverse working conditions

They may be aggravated (provoked), accelerated, or

exacerbated (worsted) by workplace exposures, They may impair working capacity

However, personal characteristics and other

environmental and socio-cultural factors usually play arole as risk factors in work related diseases, which areoften more common than occupational diseases


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Injuries: Heat and Cold

The single formula that describes thermal comfort isgiven as:

H = M * R * CE

Where

H = body heat storage load,

M = metabolic heat gain

R = radiant or infrared heat load

C = convection heat load

E = evaporative heat loss.


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In occupations in which workers are exposed to excessive

heat, medical evaluation is recommended to identify

individual at increased risk for heat disorders due to pre-existing medical conditions or use of medications

Exposed workers should be trained to recognise early signs

and symptoms of heat disorders and should be advise of theimportance of proper attire (clothing), nutrition and fluid intake

Symptoms and signs may include intense thirst, weakness,nausea, fatigue, headache, confusion, and once core (rectal)temperature exceeds 38oC increased pulse rate,

hyperventilation, and moist skin and if core temperatureexceeds 40oC, collapse, coma and imminent death

Treatment requires rapid action, immediate replacement ofloss fluids and attempts to cool core temperature (isotonic IVdrips proving to be the most effective)


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Injuries: Burns

thermal damage

electric discharges

radiation burns electromagnetic radiation

chemicals

etc


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Natural sunlight

Workers potentially exposed to ultraviolet radiation

Agricultural workers

Brick masons

Ranchers Construction workers

Farmers

Many of the burn injuries that cause a problem in thework place may not be as obvious as the thermal and

chemical burns. For example, exposure to UV(ultraviolet) light is a major problem in a number ofindustries.


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sunlight injuries

Fishermen, Gardeners, Greenkeepers,

Horticultural workers, Landscapers, Lifeguards,

Lumberjacks, Military personnel, Oil field

workers, Open pit miners, Outdoor maintenanceworkers, Pipeline workers, Police officers, Postal

carriers, Railroad track workers, Road workers,

Sailors, Ski instructors, Sports professionals,

Surveyors are examples of potential target ofsunlight injuries.


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ultraviolet

Arc welding ultraviolet: Welders, Pipeline workers, Pipecutters,Maintenance workers

Plasma torch ultraviolet: Plasma torch operators

Germicidal ultraviolet: Physicians, Nurses, Laboratory technicians,Bacteriology laboratory personnel, Barbers, Cosmetologists, Kitchenworkers.

Laser ultraviolet: Laboratory workers

Drying and curing processes: Printers, Lithographers, Painters,Wood curers, Plastics workers.

Many of the burn injuries that cause a problem in the work

place may not be as obvious as the thermal and chemicalburns. For example, exposure to UV (ultraviolet) light is amajor problem in a number of industries


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important medical condition linked

with occupational UV exposure(i) Photokeratoconjunctivitisor "Welders Flash", symptoms occur

6-12 hours after exposure and include severe pain, photophobia,and a sensation of a foreign body in the eyes, and tearing;

(ii) Cataracts,strong association between UV exposure andcataractogenesis exists;

(iii) Eye diseases, retinal damage as well as a number of benign andcancerous cell conditions;

(iv) Erythema, (reddening of the skin), UV exposure leading tosunburn is known to most beach bathers. Erythema is mostsevere following exposure to wavelengths of 290-320nm andmay be accompanied by oedema, blistering, desquamation,

chills, fever, nausea;(v) Photosensitivity reactions, especially skin reactions in those

workers of particular medication;

(vi)Premalignant and malignant skin lesions, these usually take along time to manifest, earlier changes include acceleratedageing of skin, loss of elasticity, hyper pigmentation, wrinkles,

etc.


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Injuries: Biomedical

Injury at work due to biomechanical factors, suchmanual handling (lifting of heavy loads),inappropriate workplace designs (ergonomics) andrepetitive injuries account for a large proportion of

compensation claims Manual handing involves the application of human

effort to move equipment, materials, objects, peopleor animals. A lot of these activities can be classifiedas lifting, but other processes such as, pushing,

pulling, twisting and maneuvering play a role incarrying any object. It is no use teaching people tolift things correctly when their job involves, say,manual handling a 160L drum.


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A major factor in manual handling

injuries Poor working posture this can have a number of

adverse outcomes to the worker.

The work posture and injuries that could besustained to tissues, and body parts such as the

back, neck and wrists.

The capacity to perform manual handling variesconsiderably not only between individuals but

within any given individual over time. Factorssuch as gender, age, and body size can modifyrisks of injury


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The consequences of poor working posture.


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Injuries: Noise and Vibrations

The human ear has a remarkable dynamic

range of roughly 0 to 120 dB, which allows

for the detection of the faintest noise to

painful stimulation

Occupational hearing loss can result from

exposure to excessive noise or prolonged

exposure to high noises


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EAR ANATOMY


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Occupational hearing loss

partial or total;

unilateral or bilateral; and conductive,

sensorineural, or mixed conductive and

sensorineural in nature


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Definition of Injuries

Conductive hearing loss results from dysfunction ofthe external or middle ear, which impairs the passageof sound vibrations to the inner ear. In the workplace,this can be caused by blunt or penetrating headinjuries, explosions, and thermal injuries, such as slag

burns sustained when a piece of welders slagpenetrates the eardrum

Sensory hearing loss results from usually thedeterioration of the cochlea, usually the due to loss ofhair cells from the organ of Corte. Among the many

common causes of sensory hearing loss are continualexposure to noise in excess of 85 dB (Australian TWAstandard), blunt head injury, and exposure to ototoxicor neurotoxic substances.


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SYMPTOMS AND EFFECTS OF

INDUSTRIAL DEAFNESS

SYMPTOMS:a. Speech can be heard but the words aren't clear.

b. Inability to distinguish certain speech sounds life 'f','s' and 't'; sounds like birds singing or leavesrustling can't be heard.

c. Some sounds are distorted and 'loudnessrecruitment' occurs. This means that sounds whichare hard to hear suddenly become unbearably loudwith only a slight increase in volume.

d. Sufferer may tend to speak too loudly because theycan't hear their own voices clearly.

e. Speech becomes more difficult to hear when e c isbackground noise. it can become difficult to hear atmeetings.


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EFFECTS:

The most obvious effect of high noise levels

is

Deafness, Dizziness, Loss of balance.

Ringing in ears (Tinnitus).

Headache.

Stress and nervous effects such as

annoyance, irritability.

Reduced night vision.

Loss of sleep


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PREVENTION:

an understandingis gained in regard tothe cause of this injury.

There is only one cause, Industrial Noise.

Knowledgeof some technical aspectsabout noise is the first step towards theelimination of industrial deafness.

Stewards are urged to study the section ofthe manual carefully and to expand theirknowledge by further reading


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NOISE CHARACTERISTICS:

INTENSITY AND FREQUENCY

Noise is an unwanted or unpleasant sound

It can interfere with work and safety by

inducing stress and disturbed

concentration

It can cause serious accidents by breaking

down communications; warning signals

cannot be heard when noise levels are

high


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INTENSITY

The concentration of sound power on a

surface is called intensity


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FREQUENCY

sound power or energy is transmitted throughsound waves

The speed of air particle vibration is calledfrequency

Noise frequency is measured by the number oftimes air particles move backward and forward,(i.e., from compression areas to vacuum areasover a certain period of time

In technical terms frequency is understood andmeasured as, cycles per second' hertz or HZ forshort


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ABILITY TO HEAR AND INDUSTRIAL

DEAFNESS

OUTER EARconsisting of the portion attached to theouter surface of the head and the AUDITORY CANAL

MIDDLE EARconsisting of the eardrum and the threesmallest bones in the body, the HAMMER, ANVIL and

STIRRUP INNER EARcontaining the most complex mechanism of

all. This part of the ear consists of the COCHLEA, abony structure shaped like a snail. Inside the cochleathere are tiny hair cells mounted in a membrane which

floats in the liquid. The hair cells in turn are connectedwith the brain through the auditory nerve.


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THE HEARING PROCESS

Sound waves (vibrations) in the air are transmittedthrough the three bones in the middle ear to thecochlea of the inner ear

During this process, vibration in the air isconverted to mechanical vibration by theoscillation of the eardrum and the small bones

Finally, the mechanical vibration sets in motionfluid waves, in the cochlea.

The power carried by these waves activates thetiny hair cells which in turn send messages to thebrain through the auditory nerve. When thesemessages reach the brain, then we can say thatwe 'hear'.


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HEARING LOSS

Temporary and permanent

TEMPORARY HEARING LOSS involves theorgans of the middle and inner ear and canoccur due to exposure of excessive continuousnoise or impact noise

Impact noise, e.g. metal plates hitting each otheror from forges, hammers and presses, theeardrum can be damaged. However theeardrum can eventually repair itself. In the caseof the continuous exposure to noise the hearingcan gradually return

Temporary hearing loss will become permanentover a period of time.


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PERMANENT HEARING LOSS mainly

involves the destruction of hair cells of the

inner ear (in the cochlea Once the haircells are destroyed, they cannot be

repaired. The most insidious

characteristics of permanent hearing lossare:

(a) that there is no warning of the

destruction occurring in the inner ear(b) the loss of hearing occurs over a long

period of time


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THE EXPOSURE TO NOISE LEVELS

The amount of noise workers receive over

a certain-period of time (see Daily Noise

Dose)

The most important point to remember is

that CONTINUOUS EXPOSURE, even to

low levels, (e.g., 70 dB (A) may damage

the ear mechanisms


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THE TYPE OF NOISE

continuous and impact or impulse noise

lathe or most of the machine tools will

produce a continuous noise

steel plate dropped on another will

produce impact noise which is more

intense and more dangerous

rivet guns or pneumatic wrenches will emit

impulse noise but in very short intervals


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NOISE MEASUREMENTS AND LEGAL

STANDARDS

hazard has to be measured first before action is taken toeliminate it

MEASUREMENT: THE dB(A) scale is that designed tomeasure noise levels and frequencies which can be

hazardous to the human ear. The dB is a unit of sound (noise) pressure

The (A) next to dB indicates that noise is measuredwithin a certain range of frequencies (approximately 25Hz8000 Hz). At the same time the (A) indicates alsothat in noise measurement only some intensities arebeing taken into account.


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THE CONCEPT OF DAILY NOISE DOSE

used to assess the degree of potential danger tohearing

the average acoustic power, which the earreceives during a working day

daily dose is the average of ALL NOISE levels,which the human ear is coursed to in an 8 hourperiod

the instrument used to measure the daily noise

dose is called a DOSIMETER. Its electroniccircuit averages out automatically all the noiselevels received and the results can be read atanytime and for any portion of the day.


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LEGISLATION

legislation regulates reduction of exposure tonoise by ENGINEERING CONTROLS andPERSONAL PROTECTION

Two important concepts involved in noise

regulation are: NOISE LEVELS and DAILYNOISE DOSE

In most States legislation will specify that - noiselevels should not exceed the 115 dB(A) mark atany time and - daily noise dose should notexceed 85 dB(A) TWA (Time Weighted Average,i.e., over the eight hour working day as anaverage of all measurements).

bahan kuliah k3 pertemuan 2

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