MECHENG352 - Industrial Environment and Ergonomics Flashcards
What is ergonomics?
Definition:-
Ergonomics is a technology that seeks to improve mental and physical wellbeing by optimising the function of “human-machine-environment” systems or “Fitting the task to the person”
From ‘ergo’ = work and ‘nomos’ = laws
What is the scope of ergonomics?
- Anthropometry - workplace design to suit the human operator.
- Biomechanics - knowledge of human physical limitations and acceptable exertions to be expected in a job.
- Work physiology - ensuring that adequate provisions are made for recovery from physically and mentally demanding work.
- Environmental engineering - the design and control of the physical environment within which the work must be undertaken.
- Skill psychology - understanding and optimising the exchange of information between the person and the equipment he or she uses.
- Occupational psychology - namely the selection, training and motivation of personnel.
Causes of musculoskeletal disorders (MSDs)
Over time, exposure to risk factors leads to MSD
risk factors: ergonomic, individual, equipment (vibration), repetition
Factors contributing to repetitive task risk factor
- Stress on muscles and tendons
- Contributing factors
o Duration and speed of repetitious movement
o Number of muscles involved o Required force
o Raising and lowering the arm over and over again
Factors contributing to forceful exertion risk factor
- Inflammation of tendons, nerves, joints
- Contributing factors
o Type of grip
o Weight of object
o Body posture
o Type and duration of the task
Factors contributing to awkward posture risk factor
- Stress on muscles and tendons
- Contributing factors
o Reaching overhead
o Force the body must maintain to hold the position
o Holding fixing positions (static loading) - Lifting while twisting, reaching, or turning
Factors contributing to contact stress risk factor
- Pressing against or grabbing a hard object puts pressure on nerves, tendons and blood vessels
- Contributing factors
o Repetition
o Duration of contact
o Grip strength required
Factors contributing to vibration risk factor
- Affects tendons, muscles, joints, nerves
- Contributing factors
o Prolonged grip
o Restricts blood supply to hands and fingers
o Tools without vibration dampening device
o Poor power tool maintenance
10 Principles of Ergonomics
Work in neutral postures
Work at proper heights
Keep everything in easy reach
Reduce excessive force
Reduce excessive motions
Minimize fatigue and static load
Minimize pressure points
Provide clearance
Maintain a comfortable environment
Move, exercise, and stretch
Environment factors in work system design
Temperature, ventilation, noise, and lighting are all factors in work system design
Importance of proper illumination
Rotating parts can look as if they are standing still. This can lead to dangerous actions such as touching.
Poor illumination can increase the chance of mistakes
Poor illumination can increase effects of colour blindness
Definition of illuminance
Definition: The amount of light falling on a surface. Measured in Lux.
1 Lux = 1 lumen/m2
Human range is approximatively from 10 lux at night,
to 100,000 lux in mid-day sun.
Definition of luminance
Definition: The amount of light emitted by objects or from surfaces. Measured in Candela/m2
10 lux is roughly 1 FC.
A measure of the brightness of a surface. Dependant on reflectivity.
Definition of luminous flux
Definition: The total amount of visible light present. Measured in lumens.
Human eye luminance range
The human eye can detect a luminance range of 1014, or one hundred trillion.
One millionth of a candela per square metre to one hundred million candelas
per square metre.
