Chapter 4 Flashcards
Ergonomic definition
The scientific study of people and their working conditions, especially done in order to improve effectiveness
Ergonomics: definition and origins
- Ergonomics is derived from the Greek language: Ergonmeans workand Nomosmeans laws, so ergonomics means work laws.
- In practice, it means gathering scientific principles to minimize the physical stress (الاجهاد البدني) at work, which helps in increasing the quality and productivity
Ergonomics involves the following:
- Using special design and evaluation techniques to make tasks, objects, and environments more compatible(suitable)with human abilities and limitations.
- Seeking to improve productivity and quality by:
- reducing workplace stress (إجهاد )(nervous feeling, worried)
- reducing the risk of injuries and illnesses, and
- increasing efficiency
Posture(position, situation)
- The position that your body is in, when you sit, stand, or walk or وضع الجسد
- The way in which someone usually holds his or her shoulders, neck, and back,
- or a particular position in which someone stands, sits, etc.:
Human Factors
a profession (a job)to help ensure that equipment and systems are safe and easy to operate by human beings
- Human Factors is a profession (a job)to help ensure that equipment and systems are safe and easy to operate by human beings.
- They do this task as follows:
- predesign analysis
- prelimnary design
- detail design and development
- test and evaluation
predesign analysis
Human factors professionals conduct research to determine what factors contribute to fatigue(extreme tireness) (تعب). and stress and how designers can overcome these factors
Preliminary (first, primary) Design
•Human factors professionals study machine and human capabilities(skills)to determine which tasks should be undertaken manually and which should be automated.
Detail Design and Development:
•Human factors professionals define the environment required for
- safety operation,
- enhanced operator performance, and
- the reduction or prevention of operator stress and fatigue (extremetireness) (تعب).
Test and Evaluation
Human factors professionals testactual humans while using the prototype(model)equipment or system
Human Factors and Safety
•How the science of human factors reduce (make less)product & workplace hazards:
- Hazard elimination by design
- Provision and location of safety devices
- Provision of warning devices
- Establishment of procedures/provision of traning
Hazard elimination (إزالة)by design
•Intelligent design can reduce human error by providing controls that are simple to understand and operate.
Provision (supply)and location of safety devices
Design and location of safety devices such as emergency cutoff switches can reduce human error on the job, resulting in reducing the chances of an accident.
Provision(supply) of warning devices
- Color, location, and wording of warning devices; and
- volume of warning signals
- and video displays
are all important factors in reducing the likelihood of a human error that might lead to an accident
Establishment of procedures/provision of training
•When hazards cannot be designed out of a system, administrative procedures for hazard reduction must be established and training related to those procedures must be provided.
Factors Associated With Physical Stress
- Sitting versus standing: Generally speaking, sitting is less stressful than standing (but not necessarily in all cases).
- Large versus small demand for strength/ power: Jobs that demand large amounts of strength/power are generally more stressful than those that require less
- Non repetitive versus repetitive motion: Repetition can lead to monotony (same) and is boring (ممل). When this happens the potential for physical stress increases.
- Absence versus presence of negative environmental factors: The more environmental factors, the more stressful the job. (personal protective equipment reduce environmental hazards, but increase the amount of physical stress).
OSHA Voluntary (ختياري) ) Ergonomic Guidelines
This program amounts to assigning (giving) responsibility for ergonomics to individual and informing employees about the risks of MSD(musculoskeletal disorders اضطراب الجهاز العضلي الهيكلي) related injuries, symptoms of such injuries and why early reporting of symptoms (signs,الأعراض) is important.
OSHA Voluntary Ergonomic Guidelines
the basic program requires employers to
establish a system that employees can use to report symptoms of MSD injuries
CTD stands for
Cumulative trauma disorders
Risk factors associated with CTDs
(Cumulative Trauma Disorders)
- Repetitive and/or prolonged activities
- Forceful exertions (strain) usually with the hands
- Prolonged static postures (situation, status, position)
- Awkward (unsuitable) postures of the upper body, including reaching above the shoulders, behind the back, and twisting the wrists and other joints to perform a task.
- Excessive vibration from power tools
- Cold temperature
- Inappropriate or inadequate tool design
- Fatigue
- High wrist acceleration
- Use of gloves
Steps in Conducting Ergonomic Job Hazard Analysis
- Workstation Analysis
- identify all risk factors present in each studied job or workstation
- e. g. Lifting hazards for manual materials handling (the maximum weight-lifting values should be calculated)
- DVD (Video method):
- for analysis of work process (watch how each worker actually performs each task)
- Periodic ergonomic surveys
- to identify previously unnoticed factors, failures or deficiencies. (lack, shortage)
- Feedback and follow up
- A reliable (dependable) system to let the workers report risk factors or ergonomics hazards to management (identify risks to control them).
- Trend Analysis
- •(Tendency or general direction of movement)
- using several years of data –for departments, processes, job titles, or workstations.Can be used to determine which positions, machines, jobs are most hazardous
Hazard Prevention and Control Program
- workstation design
- designed to accommodate the person who actually use them (not average to be used by everyone), must be comfortable, and easily adjustable
- design of work methods
- Static postures (position), and repetition rates should be supplemented by addressing force levels on the hand and arm postures involved (to reduce CTDs) (Cumulative Trauma Disorders)
- Tool design and handle
- Tools should be selected and designed to minimize the risk of upper extremity CTDs and back injuries
- Variety of sizes should be available (design tools that can be used by right-handed and left-handed workers, design tools with less vibration,design tools for minimum weight, …etc).
Participation in Ergonomics CTD
(Cumulative Trauma Disorders).
Training Program
- All employees including supervisors and other plant management personnel should participate in the training and education on the different types of CTDs and means of _preventing causes of early symptoms, and treatment of CTD_s.
- This information should be emphsizedduring workplace instructions and the individual health surveillance appointments.
- All new employees should be given such training during orientation
- This will facilitate (يسهل)early recognition of CTDs, and increase the likelihood of compliance(obeying)with prevention and treatment
Common Indicators of Ergonomic Problems
- Apparent (obvious)Trends in Accidents and Injuries
- Incidence of Cumulative Trauma Disorders (CTDs)
- Absenceand High Turnover Rates
- Employee Complaints
- Employee Generated Changes
- Poor Quality
- Manual Material Handling
Apparent (obvious)Trends in Accidents and Injuries:
•when examining accident reports, medical logs, insurance forms, …etc. A pattern or high incidence rate of a specific type of injury indicates that an ergonomic problem exits.
Incidence of Cumulative Trauma Disorders (CTDs)
By observing workplace that include a high level of
- repetitive work,
- hand force,
- awkward posture,
- vibration,
- mechanical stress,
- extreme temperatures
we can measure ergonomics related problems
Absenceand High Turnover Rates
(therate at which employees leave a workforce and are replaced)
•indicators of ergonomic problems (might leave the work for a less stressful work).
Employee Complaints
•high incidence or employee complaints can indicate ergonomic problems.
Employee Generated Changes
workplace additions can be evidence of ergonomic problems (extra lighting, …etc.)
Poor Quality
•can be indicator of ergonomic problems (or at least an indicator of a need for closer inspection).
Manual Material Handling
•lifting large objects, bulky objects, lifting objects from the floor, and lifting frequently.
Identifying Specific Ergonomic Problems
- General observation
- Questionnairs and interviews
- videotaping and photography
- drawing or sketching
- measuring the work environment
- understanding the ergonomics of aging
- seated repeatitive work with light parts
- work with hands above the chest
- work wth hand tools
General Observation
•Effective way (especially if the worker does not know that you are watching him). Be watchful to tasks requiring manual material handling and repetitive movements.
Questionnaires and Interviews
Questionnaires are easy to distribute, tabulate and analyze. Interviews provide more in depth information
Videotaping and Photography
records work being done to identify any specific ergonomic problem
Drawing or Sketching
Showing workflow can help identify problems
Measuring the Work Environment
•How far must a worker carry the material manually? How high does a worker have to lift an object? How much does an object weigh?
Understanding the Ergonomics of Aging
adapt the job to the person (not the person to the job). Range of motion, flexibility, velocity, and muscle mass begins to diminish (decrease)by age 45. Lower back pain is common in people over 45
Seated Repetitive Work With Light Parts
•Back, neck, shoulder, and lower leg pain are common. Include other work tasks to break the monotony of repetition. Use adjustable chair.
Work with Hands above the Chest
Neck, upper body and heart strain
Eliminate manual lifting to the extent possible by raising work floor or using lifts
Work with Hand Tools:
•Carpal tunnel syndrome (CTS)- wrist [numbness, tingling, or burning sensations in the thumb and fingers], and muscle strains of the lower arm, hands and wrist.
Improve hand positions during use of tools, enhance worker’s grip on tools, and minimize amount of twisting involved.
CTD(Book definition)
•isa term that covers a number of injuries caused by forceful or awkward movements repeated frequently over time. CTDs occur to the muscles, nerves, and tissuesof the hands, arms, shoulder and neck.
CTD (General definition)is
•a condition where a part of the body is injured by repeatedly overusing or causing trauma to that body part.
Traumaoccurs when
•the body part is called on to work harder, stretch farther, impact more directly or otherwise function at a greater level than it is prepared for.
•Traumaoccurs when the body part is called on to work harder, stretch farther, impact more directly or otherwise function at a greater level than it is prepared for.
The immediate impact may be
very little, but when it occurs repeatedly the constant trauma cause damage
