t4_workplace env & ergo

7/30/2019 t4_workplace Env & Ergo

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TOPIC 4WORKPLACE ENVIRONMEAND ERGONOMICS


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Content

History of Ergonomics Objectives of Ergonomics

Workplace Design Principles

Ergonomic Risk :

Musculo-Skeletal-Disorders(MSD)

Workplace Environment


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Definition of

Ergonomicsfrom the Greek words :

Ergos means work

nomos means principles oflaws


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Definition of

Ergonomics Ergonomics is the science of designing ajob, equipment and workplace to fitworkers.

Ergonomics can be simplified as being thestudy of man in relation to hisenvironment.

Proper ergonomic design is necessary toprevent repetitive strain injuries, which candevelop over time and can lead to long-term disability.


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History Of Ergonomics

Hellenic civilization in 5th century BC used

ergonomic principles in the design of their tools,

jobs and workplaces.

In early years, Egyptians Dynasties made tools,household equipment that illustrated ergonomic

principles.

In 19th century, "Scientific Management" method

proposed path to find the optimum method for

carrying out given task was introduced.

Taylor, found that the amount of coal shoveled

could be tripled by incrementally reducing the size

and weight of coal shovels until the fastest

shoveling rate was reached.


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History Of Ergonomics Lillian Gilbreth expanded Taylor's methods in

the early 1900s to develop "Time and Motion

Studies".

They aimed to improve efficiency by

eliminating unnecessary steps and actions.

By applying this approach, the Gilbrethsreduced the number of motions in bricklaying

from 18 to 4.5, allowing bricklayers to

increase their productivity from

120 to 350 bricks per hour.


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Objectives of

Ergonomics To facilitate the maximization both comfort and

productivity in the workplace.

Secure health, safety and comfort of personsdoing the work.

To successfully develop environments that

comfort to the workers/ people.

To achieve better work efficiency andeffectiveness.


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Workstation Design

Principle Adjust the height of work according to body dimensions,using elbow height as guidance.

Organize work so that usual operations can be done

within easy reach

Adjust workplace to gain enough space to change

work position.

Use a foot rail or portable footrest to shift body weight

from both to one or the other leg.

Use a seat whenever possible while working or at least

when the work process allows for rest.


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Sitting Work Position Adopt a good sitting position by learning how to adjust the

workstation to fit individual needs for specific tasks

Select a chair with :

- controls that are easy to operate from sitting position- a seat that adjusts for both height and tilt

- a seat that does not put pressure the back of thighs or knees

- a backrest that is shaped to support the lower back and

does not give way

- a front edge curved downwards- non-slip, breathable fabric on the seat

- a stable five-point base

- a minimum seat width of 400mm

- arm rest where practical, that do not interfere with free

movements within the workstation


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Sitting Work Position

Adjust the chairs height to 250 -350mm

below the work surface.

Introduce five minutes of exercise, such as

walking for every 40 to 50 minutes of sitting.

Activity breaks such as work-related tasks

away from the desk or simple exercises which

employee can carry out on the worksite.


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Good Sitting Work Position


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Prolonged sitting :

- reduce body movement, making muscles more likely to

pull, cramp or strain when stretched suddenly

- Causes fatigue in the back and neck muscles by

slowing the blood supply and puts high tension on the

spine, especially in the low back or neck.

- causes a steady compression on the spinal discs


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Standing Work Position

Can be categorized based on leg

movements such as :

Dynamic activity : with leg movements

Static activity: with less or no legmovements

or combination of both

Is define as a workstation where a task is

performed with the employee standing in a

relatively stationary position and without


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Standing Work Position

Different tasks require different work surface heights: Precision work, such as writing or electronic assembly

- 5 cm above elbow height; elbow support is needed.

Light work, such as assembly-line or mechanical jobs

- about 5-10 cm below elbow height.

Heavy work, demanding downward forces

- from 20-40 cm below elbow height


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What can workers do to reduce the discomfof working in a standing position?

Adjust the height of the work according to

body dimensions, using elbow height as a guide.

Organize your work so that the usual

operations are done within easy reach


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Always face the object of

work.

Keep body close to the work.

Adjust the workplace to getenough space to change

working position.

Use a foot rail or portable

footrest to shift body weight

from both to one or the other

leg.

Use a seat wheneverossible while workin or at

What can workers do to reduce the discomfof working in a standing position?


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What should workers avoid whileworking in a standing position?

Avoid reaching behind the shoulder line.

Shifting feet to face the object is therecommended way.

Avoid overreaching beyond the point of

comfort.

Avoid reaching above shoulder line


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The basic of neutral working postures


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Ergonomics Risk


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Musculoskeletal Disorders (MSDs)

Musculoskeletal disorders (MSDs) are

injuries of the muscles, nerves, tendons,

ligaments, joints, cartilage or spinal discs.

MSDs are not typically the result of any

instantaneous or acute event (such as a slip,

trip, or fall) but reflect a more gradual or chronic

development.


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Ergonomics - Risk Factors for M

Forceful Exertions

Repetitive Motions - lead to overuse of muscles and tendons

Awkward Postures

- body positions that are uncomfortable

Static Postures - positions held for long periods of time cancause fatigue

Contact Stress - occurs when there is pressure exerted on abody

Lighting

Vibration - reduces the ability of the muscles to contract andleads to more rapid fatigue

Noise


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Repetitive stress injuries often affect the hands, wrists, arms,

elbows, shoulders, back and neck. If you suspect that you

have a problem contact your physician. Some of the warning

signs are listed below:

Presence of tingling, numbness or loss of sensation

Inability to make a fist

Weakness

Cold hands Lack of control or coordination

Having to frequently self massage

Pain or soreness

Swelling, inflammation or stiffness in joints

Warning Signs of MSD


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Effects of MSD

Repetitive Strain Injuries (RSI)

Cumulative Trauma Disorders

Repetitive MotionDisorders

Loss inProductivity


30/48WORKPLACE ENVIRONM


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Workplace Environment


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INDOOR AIR QUALITY


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Indoor Air Quality Effects on Respiratory Sy

Poor air quality can effects human health : respiratory

system and cardiovascular system

Individual reactions to air pollution depends on :

- the type of pollutant a persons exposed- degree of exposed

- health status

- genetics

Health effects caused by air pollutions :

- difficulty in breathing

- wheezing

- coughing


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LIGHTING & SIGHTEDNE


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Measure Lighting and Sightedness

Lightning.

When planning the layout of Visual Display Unit

workstations the following points should be

considered with regard to lighting.

Avoid:

- Gloom and harsh light equally.

- Glare from unshielded light sources,

artificial and natural, and reflections in the

operator's field of view.

-Screen reflections.


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Measure Lighting and Sightedness

Ensure:

Levels of 300-500 lux on the working plane.

Use of diffusers with a narrow angle of light

distribution on overhead light sources or providediffuse lighting from indirect sources,

complemented where necessary with task lighting.

Low reflectance work surfaces and equipment

with matt finished surrounds.


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Measure Lighting and Sightedn

Levels of 300-500 lux on the working plane.

Where possible locate screens between and

parallel to overhead light units and at right angles

to windows. Screens should never face or backon to windows unless adequate control of

daylight glare is available.

Where indirect lighting or low luminance light

sources are used, ensure that the surface

reflectivity of walls, ceilings and floor are higher

than that used for other forms of lighting.

Screen Filters


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a. The work desk or work surface shall have a sufficientlylarge, low-reflectance surface and allow a flexible

arrangement of the screen, keyboard, documents and

related equipment

b. The document holder shall be stable and adjustable andshall be positioned so as to minimize the need for

uncomfortable head and eye movements.

c. There shall be adequate space for operators or users to find

a comfortable position.

d. The workstation shall be dimensioned and designed so asto provide sufficient space for the operator or user to

change position and vary movements.

e. The symbols on the keys shall be adequately contrasted

and legible from the design working position

Measure Lighting and Sightedn


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TEMPERATURE & HUMIDI


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- Temperature and relative humidity are two of

several parameters that affect thermal comfort.

- Satisfaction with the thermal environment canalso be influenced by such factors as radiant

temperature, air velocity, occupant activity level,

and clothing.

Measure Temperature and Humi


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- Relative humidity levels below 25% are associated

with increased discomfort and drying of the mucous

membranes and skin, which can lead to chapping

and irritation.

- Low relative humidity also increases static

electricity, which causes discomfort and can hinder

the operation of computers and paper-processingequipment.



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- High humidity levels can result in

condensation within the building structure

and on interior or exterior surfaces and the

subsequent development of moulds and fungi

* In large buildings, the air supply is humidified over

the winter season, usually by a water spray or steam

system. Water spray humidifiers require regularscheduled maintenance to control water quality. Steam

humidifiers are cleaner and easier to maintain, but use

more electrical power. In the summer, the air

conditioning dehumidifies the outdoor air supply



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NOISE & HEARING


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Measure Noise and Hearing Qua

The term hearing describes the process, function, or power of perceivingsound.

Types of Noise :

Steady: Continuous noise of sudden or gradual onset and longduration (more than one second). Examples: aircraft powerplant

noise, propeller noise, and pressurization system noise. According to theOccupational Safety and Health Administration (OSHA), the

maximum permissible continuous exposure level to steady noise in a

working environment is 90 dB for eight hours.

Impulse/Blast: Noise pulses of sudden onset and brief duration (less thanone second) that usually exceed an intensity of 140 dB. Examples:

firing a handgun, detonating a firecracker, backfiring of a piston

engine, high-volume squelching of radio equipment, and a sonic

boom caused by breaking the sound barrier. The eardrum may be

ruptured by intense levels(140 dB) of impulse/blast noise


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Effects of Noise Exposure

Physiological- Ear discomfort may occur during exposure to a 120 dB noise.

- Ear pain may occur during exposure to a 130 dB noise.

- Eardrum rupture may occur during exposure to a 140 dB noise.- Temporary hearing impairment. Unprotected exposure to loud,

steady noise over 90 dB for a short time, even several hours, may

cause hearing impairment. This effect is usually temporary and

hearing returns to normal within several hours following cessation

of the noise exposure.- Permanent hearing impairment. Unprotected exposure to loud

noise (higher than 90 dB) for eight or more hours per day for

several years, may cause a permanent hearing loss.


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Effects of Noise Exposure

Psychological- Subjective Effects: Annoying high-intensity noise can cause

distraction, fatigue, irritability, startle responses, sudden

awakening and poor sleep quality, loss of appetite,headache, vertigo, nausea, and impair concentration and

memory.

- Speech Interference: Loud noise can interfere with or mask

normal speech, making it difficult to understand.

- Performance: Noise is a distraction and can increase the

number of errors in any given task. Tasks that require

vigilance, concentration, calculations, and making judgments

about time can be adversely affected by exposure to loud

noise higher than 100 dB.


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How to Protect Your Hearing

Earplugs: Insertable-type earplugs, must be inserted properly to create anair-tight seal in the ear canal.

Communication Headsets :more easily donned and removed than earplugs

Active Noise Reduction Headsets. :This type of headset uses active noisereduction technology that allows the manipulation of sound and signal waves

to reduce noise, improve signal-to-noise ratios, and enhance sound quality.

Combinations of Protection Devices : The combination of earplugs withearmuffs or communication headsets is recommended when ambient noise

levels are above 115 dB. Earplugs, combined with active noise reduction

headsets, provide the maximum level of individual hearing protection that can

be achieved with current technology


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