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Pertemuan Pertemuan 1010

Matakuliah : D0194 / Perancangan Sistem Kerja & Ergonomi

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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 )

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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 )

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Illustration of the distribution of light from a light source following the inverse-square law

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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.

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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 )

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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.

9Decibel values of typical sounds (dBA)

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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.

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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.

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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.

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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.