Hawassa University
Institute of technology
Faculty of Manufacturing
Department of Industrial Engineering
INDUSTRIAL SAFETY AND ERGONOMICS:
Nebiyou
G (Lec).
Part one: Introduction to Ergonomics
1.1.What is ergonomics ?
The word ergonomics comes from two Greek words:
 ERGO: meaning work
 NOMOS: meaning laws
Therefore, ergonomics is the law of work.
 Ergonomics is a science focused on the study of human fit, and
decreased fatigue and discomfort through( e.g product design,
work station design.)
 Ergonomics is commonly defined as a scientific study focused on
the relationship between man, machine and environment.
Meaning of Ergonomics
 Ergonomics is the scientific discipline concerned with:
 understanding of the interactions among humans and other
elements of a system, and
 the profession that applies theory, principles, data and methods to
design, in order to optimize human well-being and overall system
performance.
 Ergonomics is the science of designing the job to fit the worker,
rather than physically forcing the worker’s body to fit the job.
 The application of ergonomics principles to workstation design can
result in increased effectiveness, work quality, health and safety and
job satisfaction.
Understanding Ergonomics
Dimension of workstations <<
worker’s body dimensions.
 Ergonomics puts people first,
taking
into
account
their
capabilities and limitations.
 Ergonomics can contribute to
human well-being in terms of
safety, health, and comfort.
Fitting the job to the worker
When job fit the user, the result
can be more comfort, higher
productivity, and less stress.
Ergonomics is defined as:
 the design of:
 workplace,
 equipment,
 machine,
 tool,
 product,
 environment,
 and system,
 considering human’s capabilities and optimizing effectiveness
and productivity of work systems while assuring safety, health,
and wellbeing of workers.
- Safety
- Health
-Wellbeing of workers
Assuring
Ergonomics
Work systems:
-Effectiveness and
- Productivity
Optimizing
Is
Design of:
- workplace
- Equipment
- Machine/ tool
- Product
-Environment and
- System
Considering
Human’s capabilities like:
- Physical
- Physiological
- Biomechanical
- Psychological
1.2. Historical background of Ergonomics
• Ergonomics developed into a recognized field during the Second
World War,
• Physiologists, psychologists, anthropologists, medical doctors,
scientists and engineers worked together to address the problems
arising from the operation of complex military equipment.
• Interest in the approach grew rapidly, especially in Europe and the
United States, leading to the foundation in England of the first
ever national ergonomics society in 1949, which is when the term
‘ergonomics’ was adopted.
Why do we need Ergonomics?
Ergonomics is used to prevent injuries and illness.
Examples of risk factors that can cause discomfort, fatigue, injury and
illness are:
 Stretching to reach/Arms Extended
 Repeated heavy lifting/Frequent Hand Use
 Using High pinch force
 Working with hands above shoulder
 Handling objects which are sharp, very hot or cold
 Static body posture
 Noise, vibration
 Bending and twisting
Examples on: Risk Factors
Effects on the Operator
 Fatigue
 Pain
 Illness – sprains, back ache,
etc
 Low morale
 Frustration & Irritation
Effects on the Company
 Poor Quality
 Absenteeism
 Higher costs
 Higher employee turnover
& training
THE BENEFITS OF ERGONOMICS
 Higher productivity
 Higher Quality
 Reduced operator injury
 Increased morale
 Greater job satisfaction
 Lower medical & insurance costs
 Reduced lost time
 Lower absenteeism
 Less employee turnover
1.3. Ergonomics Approaches
According to IEA (International
Ergonomics
Association),
ergonomics is broadly divided into three domains:-
1. Physical ergonomics: is concerned with human
anatomical(study of the structure of human),
anthropometric(study of human body dimension),
physiological(study of the normal functions ) and
biomechanical(study of the physical mov’t & structure)
characteristics as they relate to physical activity.
Typical examples of physical ergonomics interventions include: Designing of a workstation to allow the proper height and
reach to perform the task.
 Selecting a tool with a handle design that reduces awkward
postures for the application.
 Reducing unnecessary tasks and movements to increase
efficiency or decrease errors.
 Tilting and lifting containers to bring work to a proper height
and increase efficiency.
2. Cognitive ergonomics: is concerned with mental
processes, such as perception, memory, reasoning, and
motor response, as these affect interactions among
humans and other elements of a system.
3. Organizational ergonomics: is concerned with the
optimization of socio-technical systems, including
their organizational structures, policies, and processes.
Organizational ergonomics is concerned with topics such
as:





communication,
work design,
Teamwork,
resource management,
shift work, safety culture, job satisfaction, and
motivation.
How groups of people interact with each other in a work
environment is the core of macro ergonomics.
1.4. Ergonomics system Dimensions
People
Tasks
Tools/Equipment
Workplace Design
Work Environment
Work culture
Work Organizations
Work culture
1. People:- consider points about physical capacities,
psychological drivers, expectations and individual
differences.
2. Task Analysis:- considers points about performance
measures, quality requirements & what, how, when details.
3. Tools & Equipment:- considers points about design of
tools to suit (Persons and Tasks).
4. Workplace design:- consider points about layout of
workplace, workstation design, adjustability / adaptability
storage and transport of items.
5. Work Environment:- considers points about physical,
psychological, chemical and biological.
Physical
Chemical
Working
Environment
Biological
Noise , Vibration
Illumination ,Climate
Ventilation
Toxic gases, Toxic liquids
Odors, Chemical compounds
Fungus,
Viruses,
Bacteria
Insects
Team work , Command structure
Psychological
Pay and welfare, Shift work
Risk & Stress
Socio-psychological aspects
6. Work Organization:- consider points about job design, team
based requirements, working hours / shift work, rest breaks and
task specialization.
7. Workplace culture:- consider points about management
commitment / leadership, communication / consultation
processes and feedback / performance management.
Ergonomics Vs. Human Factors
 Human factors is synonymous with ergonomics.
 HF is the term used to describe the interaction of individuals
with each other, with facilities and equipment, and with
management systems.
 This interaction is influenced by both the working environment
and the culture of the people involved.
 HF-analysis focuses on how these interactions contributes
towards the creation of safe workplace.
Human Factors/Ergonomics
Methods Engineering vs. Ergonomics
Emphasis in Methods Engineering
Emphasis in Ergonomics and HF
 Efficiency
 Safety
 Cost reduction
 Comfort
 Labor reduction
 Interaction between human and
equipment
 Workplace layout
 Workplace environment
 Facility layout
 Fitting the work to the individual
 Elimination of waste
 Reduction of human errors
 “One best way”
 Accident avoidance
The focus of ergonomics
• The focus is on the interaction between the person and the
machine, and the design of the interface between the two
(Figure below).
• When faced with productivity problems:
 Engineers might call for better machines,
 Personnel management might call for better-trained
people.
 Ergonomists call for a better interface and better
interaction between the user and the machine – better
task design- increased outputs/productivity.
Human-Machine Systems
 Basic model in ergonomics
 Defined as a combination of humans and equipment
interacting to achieve some desired result/output
 Types of human-machine systems:
1. Manual systems
2. Automated systems
Human-Machine Interactions
System Components
1. The human
2. The equipment
3. The environment
1. Human Components
– Human senses - to sense the operation
• Vision, hearing, touch, taste, and smell
– Human brain - for information processing
• Thinking, planning, calculating, making decisions,
solving problems
– Human effectors - to take action
• Fingers, hands, feet, and voice
2. Machine Components
– The process – function or operation performed by humanmachine system
– Displays - to observe the process
• Direct observation for simple processes
• Artificial displays for complex processes
– Controls - to actuate and regulate the process
• Eg. Steering wheel, computer keyboard
3.Environmental Components
• Physical environment
– Location and surrounding lighting, noise, temperature, and
humidity
• Social environment
– Co-workers and colleagues at work
– Immediate supervisors
– Organizational culture