This document discusses ergonomics and how to optimize work efficiency while considering human limitations. It defines ergonomics as the science focusing on adapting equipment, machines, and the environment. There are constant interactions between humans and their work, influenced by environmental and human factors. Lighting, noise, vibrations, and climatic conditions can impact workers and measures are discussed to mitigate their effects. Physical and mental strain from tasks are examined along with measures to prevent issues like static strain from prolonged muscle tension or dynamic strain from repetitive motions. Specific guidelines are provided for sitting, standing, lifting loads, and creating an ergonomic office workspace.

1. MODULE 19-ERGONOMICS
SAFE COMPANY

2. DEFINITION
Concept: Science that focuses on how equipment, machines and
environment can be adapted to optimize work efficiency considering the
limitations and restrictions of man.
• By applying ergonomics principles, health and safety risks
associated with work can be reduced. Better health and productivity.
• Many poor ergonomics practices can be improve with relative simple
measures (sometimes minor and non expensive)
• Major risks: awkward postures, repetitive movements, excessive
force.

3. MAN-WORK
Constant interaction between man and work
Man is influenced by two types of factors:
 Environmental factors (lighting, noise and vibration, and climatic
conditions)
 Human factors (physical and mental strain)

4. LIGHTING
Sufficient lighting improves concentration:
• Amount of light required depends on type of work and space.
• Preferred natural light. Direct dazzle, contrasts and light reflection
must be avoided.
• National legislations: minimum levels required.

5. NOISE AND VIBRATIONS
• Common symptoms of excess of noise: nausea, headaches
• Common symptoms of excess of vibrations . Measures: energy
absorbing gloves,
• More information: see module 18

6. CLIMATIC CONDITIONS
• Factors: temperature (20-24 cº), radiation heat, humidity, air speed
• Preventive measures: break times, sufficient drink, appropriate
clothing, protection against sunlight
• Different comfort levels depending on type of work.

7. PHYSICAL STRAIN
Examination of the postures:
• Static strain: Caused by continual tensing of muscles. Possible
effects: numbness, chronic fatigue, muscle ache and cramps.
• Dynamic strain: caused by moving the muscles with alternately
tense up and relax. Possible effects: fatigue. Muscle ache, damage
to the heart and blood vessels.
Factors that may increase the risk: protected sitting and standing,
leaning over, vibrations, repetitive movements or extreme physical
effort.

8. PHYSICAL STRAIN II
Preventive measures:
• breaks
• Back & neck: natural alignment of the 3 curves. Straight better than
rounded (more pressure in the in vertebral disks). Preventive
measure: use of machinery to avoid the risk. Adequate space.
• Arms & shoulders: avoid working with the arms above shoulder
height (overreaching). Use of platforms and adequate equipment.

9. PHYSICAL STRAIN III
• Hands & wrists: risks can be prevented using powered tools.
• Leg & feet: job rotation, PPE shoes, knee pads, use of steps instead
of jumping.
• Repetitive actions: increase the wear and tear, limited time to rest
and recover. Measures: job rotation, doing a variety of tasks.
• Excessive force: in lifting, holding, moving, pushing and pulling
objects. Measures: Movements between elbow and shoulder height,
use of supports, back rests, lifting aids…

10. LIFTING LOADS
• Possible effects: back problems and physical complaints.
• Factors: load (weight, shape and centre of gravity, wet loads), task
(frequency, movement required, distance), environment (restrictions
in movement are, type of floor, height differences), method of
carrying and person (training, physical fitting, sex, age) .
• Preventive measures: specific training, implementing aids to lift,
rotation of workers and breaks.

11. SITTING & STANDING
Sitting: proactive sitting can cause hazards. Preventive measures:
move regularly, sit properly, legs supported on the chair, back leans
against chair, use of armrests.
Standing: Prevention measure: use of stand supports.

12. MENTAL STRAIN
• Factors: work pressure, atmosphere, infrastructure, noise.
• Possible consequences: loss of concentration, depression, fatigue,
nervousness and errors. Can lead to burn-out.
• Undesirable conducts: psychosocial risk assessment is required in
some countries. Anyway, they should be minimise.

13. ERGONOMICS AT OFFICE
 Correct adjustment workstation is essential: back rest of the chair
(20 gº angle), feet rest.
 Monitor: arms line away (stand), no direct light, no reflections,
brightness and contrast adjusted
 Desk: document holder, avoid overreaching (stand up if
necessary).Objects used regularly next.
 Keyboard: arms close to the keyboard, hands not bent up or down,
elbows relaxed, not twisted, mouse next.
 Mouse: change hands, neutral position, mouse pad.

14. ERGONOMICS AT OFFICE II
• Phone: avoid holding the phone under the chin, head sets.
• Laptops: for short periods of time. Additional measures for long
periods.
• General preventive measures: regular breaks, changing tasks
periodically, stretching.