Matakuliah
: D0194 / Perancangan Sistem Kerja & Ergonomi
Pertemuan 10
1
Method analysts should provide good, safe,
comfortable working conditions for the operator.
In addition to increasing production, ideal working
conditions improve the safety record, reduce
absenteeism, tardiness, and labor turnover, raise
employee morale, and improve public relations.
( Sumber : Niebel& Freivalds, ( 2003 )
2
The amount of light striking a surface, or a
section of this sphere, is termed illumination or
illuminance.
Some of that light is absorbed and some of it is
reflected (for translucent materials, some is
also transmitted), which allows humans to ‘see’
that object and provides a perceptions of
brightness.
( Sumber : Niebel& Freivalds, ( 2003 )
3
Illustration of the distribution of light from a
light source following the inverse-square law
4
Examples of placement of supplementary luminaires :
(a) Luminaire located to prevent veiling reflections and reflected glare;
reflected light does not coincide with angle of view. (b) Reflected light
coincides with angle of view. (c) Low-angle (grazing) lighting to
emphasize surface irregularities. (d) Large-area surface source and
pattern are reflected toward the eye. (e) Transillumination from diffuse
source.
5
Both color and texture have psychological effects
on people. For example, yellow is the accepted
color for butter, therefore, margarine must be
made yellow to appeal to the appetite.
Perhaps the most important use of color is to
improve the environmental conditions of the
workers by providing more visual comfort.
Analysts use colors to reduce sharp contrasts,
increase reflectance, highlight hazards, and call
attention to features of the work environment.
( Sumber : Niebel& Freivalds, ( 2003 )
6
From the analyst’s point of view, noise is any
unwanted sound. Sound waves originate from the
vibration of some object, which in turns sets up a
succession of compression and expansion waves
through the transporting medium (air, water).
Thus, sound can be transmitted not only through
air and liquids, but also through solids, such as
machine tool structure.
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Sound can be defined in terms of the
frequencies that determine its tone and
quality, along with the amplitudes that
determine its intensity.
Frequencies audible to the human ear
range from approximately 20 – 20.000
cycles per second, commonly called
Hertz and abbreviated Hz.
8
Decibel values of typical sounds (dBA)
9
The personnel in the area can wear hearing
protection, though in most cases, OSHA
(Occupational Safety & Health
Administration) accepts this as only a
temporary solution.
Personal protective equipment can include
various types of earplugs, some of which are
able to attenuate noises in all frequencies up
to sound pressure levels of 110 dB or more.
10
Textile workers are subjected to the hot,
humid conditions needed for weaving
cloth.
Miners are subjected to hot working
conditions due to the increase of
temperature with depth, as well as a
lack of ventilation.
11
If a room has people, machinery, or
activity in it, the air in the room will
deteriorate due to the release of odors,
the release of heat, the formation of
water vapor, the production of carbon
dioxide, and the production of toxic
vapors.
Ventilation must be provided to dilute
these contaminants, exhaust the stale
air, and supply fresh air.
12
Vibration can cause detrimental effects
on human performance.
Vibrations of high amplitude and low
frequency have especially undesirable
effects on body organs and tissue.
The parameters of vibration are
frequency, amplitude, velocity,
acceleration, and jerk.
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Management can protect employees
against vibration in several ways.
Seat suspension systems hydraulic shock
absorbers, coil or leaf springs, rubber
shear-type mountings, or torsion bars may
be used.
In standing operators, a soft, elastomer
floor mat usually preves helpful.
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