WORKPLACE ENVIRONMENT

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WORKPLACE ENVIRONMENT ERGONOMICS

• CHAPTER 4

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ERGONOMICS-What is it?

• Derived from two Greek words
• Nomoi meaning natural laws
• Ergon meaning work
• Hence, ergonomists study human
• capabilities in relationship to work
• demands

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History

• As early as 18th century doctors noted that
  workers who required to maintain body positions
  for long periods of time developed
  musculoskeletal problems.
• Within last 20 years research has clearly
  established connections between certain job tasks
  and RSI or MSD.

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Focus and Objectives of Ergonomics cont

• The focus is that people (their abilities and
  limitations) and their requirements are
  considered when
• Objects, systems which people use and operate
  within are being designed and developed
• Procedures to carry out work are being developed
• Facilities which involve and affect people are
  being evaluated.

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Focus and Objectives of Ergonomics

• The objectives of Ergonomics are
• Enhance and optimize the effectiveness with which
  work and other human activities are carried out
• Also to maintain certain desirable human values
  in the process, e.g. health, safety
• Stimulate work interest and satisfaction.

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Effects of poor Ergonomics

• Discomfort
• Accidents and injuries
• Fatigue
• Errors
• Illness
• Annoyance
• Productivity down

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What two elements are at work?

• Static work musculoskeletal effort required to
  hold a certain position, even a comfortable one.
• Example sit work at computers
  keeping head and torso upright requires small
  or great amounts of static work depending on the
  efficiency of the body positions we chose.

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Elements at work (cont)

• Force amount of tension our muscles generate
• Example tilting your head forward or
  backward from a neutral, vertical position
  quadruples the amount of force acting on your
  lower neck vertebrae
• Increased force is due to increase in muscular
  tension needed to support head in a tilted
  position

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3 Main Ergonomic Principles

1. Work activities should permit worker to adopt
   several different healthy and safe postures.
2. Muscle forces should be done by the largest
   appropriate muscle groups available
3. Work activities should be performed with joints
   at about mid-point of their ROM (esp.
   head,trunk,UE)

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FACTS

• The average person working at a keyboard can
  perform 50,000 to 200,000 keystrokes a day
• Overexertion, falls RMI are the most common
  cause of workplace injury
• An average of 125,000 back injuries due to
  improper lifting each year.
• Muscles overuse results in tiny tears in the
  muscles and scarring these contribute to
  inflammation and muscle stiffness

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A Bit of Anatomy !!

• Overuse and small repetitive movements ie
  cumulative trauma disorder (CTD), repetitive
  stress injury (RSI), musculoskeletal disorder
  (MSD) disturb balance of muscles, tendons,
  ligaments and nerves

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What causes Nerve Compression or Entrapment?

1. Repeated motions
2. Tight muscles
3. Inflammation of surrounding tissues
4. Misalignment of the nerve

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What are 4 Common Nerve injuries?

• Thoracic Outlet Syndrome brachial plexus
  compression due to muscle tightness side of neck
  from poor head position or slumped posture.
• signs and symptoms (S/Sx)
  numbness/tingling in hand, made worse w/overhead
  activities or cradling phone between ear and
  shoulder

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Nerve injuries (cont)

• Radial tunnel syndrome compressed radial nerve _at_
  outside of elbow d/t repetitive wrist finger
  extension or turning of forearm
• S/Sx Sensations from elbow to base of
  thumb w/ wrist weakness a common sx

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Nerve injuries (cont)

• Cubital tunnel syndrome ulnar nerve compression
  inside of the elbow d/t repetitive bending of
  elbow or resting your elbow on a hard surface
• S/Sx numbness or tingling and
  inside of arm w/ tingling to ring little fingers

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Nerve injuries (cont)

• Carpal tunnel syndrome compression of median
  nerve at level of carpal tunnel
• Where is carpal tunnel? Formed _at_ wrist by
  ligament over the carpal bones in hand
• S/Sx numbness or tingling in thumb, index, or
  middle finger ½ of ring finger often awakened
  _at_ night by hand falling asleep
• Sx increased by driving or attempting to hold
  objects dropping objects is a common complaint

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Tendons and Tendonitis

• Tendons are connective tissue that attach muscle
  to bone have little stretch or rebound
• Tendon overuse, static or prolonged
  positioninflammation or tendonitis
• Tendons of wrist hand very small _at_ high risk
  for injury w/ overuse
• Tennis elbow or lateral epicondylitis affects
  finger extensor tendons outside of elbow
• Golfers elbow or medical epicondylitis affects
  finger flexor tendons inside of elbow

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What to do ??
PREVENT, PREVENT, PREVENT !!!

• Warm up stretch before activities that are
  repetitive, static or prolonged
• Take frequent breaks from ANY sustained posture
  every 20-30 minutes
• Respect pain- positions or stop painful
  activity
• Recognize early signs of inflammatory process,
  tx early

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Maintain Neutral Posture

• Maintain erect position of back neck w/
  shoulders relaxed
• Position equipment work directly in front of
  and close to your major tasks
• Keep upper arms close to the body, elbows 90-100
  degrees
• Keep feet flat on floor, upper body weight
  resting on sits bones
• Wrists as neutral as possible safe zone for
  wrist movement is 15 degrees in all directions

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You talking to me?

• Avoid bending neck forward for prolonged periods
  of time (remember quadruple the force) use a
  copy holder
• Avoid static positions for prolonged time
  muscles fatigue---MOVE to circulation!

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Modify Tasks

1. Alternate activities frequently rotate heavy
   /or repetitive tasks w/ lighter less repetitive
   ones.
2. If sx become worse REASSESS task setup look for
   alternative methods
3. Avoid repetitive or prolonged grip activities
4. Avoid pinching w/ wrist in flexion or wrist
   deviation (bending to side)
5. Take frequent breaks to stretch rest hands

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Body Mechanics

• Use the largest joints muscles to do the job
• Use 2 hands to lift rather than one, even with
  light objects and tasks.
• Avoid lifting w/ the forearm in full pronation
  (palm down) or supination (palm up)
• Slide or push pull objects instead of lifting
• Keep reaching to a minimum
• Carry objects close to body at waist level

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Correct Incorrect Techniques
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Good and Bad of TILT
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Recommended Position FOR Computer user
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ERGO REMINDERS from Stretchbreak.com
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Practice Wellness at Work and Home !
Exercise
Relaxation
Nutrition
Spirit
Mind
Body
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MOVE
STRETCH
BREATHE
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An ounce of Prevention is worth a pound of cure !
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Ergonomics in occupational health and safety

• 1. User

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2. Machine
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3. Workplace
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3. Environment
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4. Special questions
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Indoor Air Quality

• Indoor air quality (IAQ) is a term referring to
  the air quality within and around buildings and
  structures, especially as it relates to the
  health and comfort of building occupants

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Indoor Air Pollution

• The National Health and Medical Research Council
  (NHMRC- Australia) defines indoor air as air
  within a building occupied for at least one hour
  by people of varying states of health. This can
  include the office, classroom, transport
  facility, shopping centre, hospital and home.
• Indoor air quality can be defined as the totality
  of attributes of indoor air that affect a
  person's health and well being.

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Sick building syndrome

• Condition associated with complaints of
  discomfort including headache nausea dizziness
  dermatitis eye, nose, throat, and respiratory
  irritation coughing difficulty concentrating
  sensitivity to odors muscle pain and fatigue.

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Sick building syndrome

• The specific causes of the symptoms are often not
  known but sometimes are attributed to the effects
  of a combination of substances or individual
  susceptibility to low concentrations of
  contaminants.
• The symptoms are associated with periods of
  occupancy and often disappear after the worker
  leaves the worksite.

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Cause of SBS

• Inadequate ventilation 52
• Contamination from inside building 16  
• Contamination from outside building 10
•  Microbial contamination  5
•  Contamination from building fabric  4
• Unknown sources 13

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Thermal Comfort

• Personal factors (health, psychology, sociology
  situational factors)
• Air temperature
• Mean radiant temperature
• Air movement / velocity (see wind chill factor)
• Relative humidity (see also perspiration)
• Insulative clothing
• Activity levels.

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Sources of Indoor Pollutants

• Base on Specific Building
• Combustion activity
• Furniture
• Chemical
• Building materials
• Food
• Water
• Smoking activity
• Outdoor air pollution

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Walkaround Inspection

• Potential Problem Areas
• Sample Collection

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Contaminant Range Screening Method Validation Method
Bioaerosols 0-1,000 cfu/m3 Viable biological sampler
Carbon dioxide 0-2,000 ppm DT, IR Sampling bag, GC/TCD OSHA ID172
Carbon monoxide 2-50 ppm DT, meter Sampling bag, meter
Formaldehyde 0.04-1 ppm DT Coated XAD-2, GC/NPD OSHA-52
Nitric oxide 0-25 ppm DT TEA tube with oxidizer, DPP OSHA ID190
Nitrogen dioxide 0-5 ppm DT TEA-Molecular Sieve Tube, IC OSHA ID 182
Particulates 0-40,000 particles/cc Light scattering meter  
Pesticides (See OSHA Chemical Information Manual) (See OSHA Chemical Information Manual) (See OSHA Chemical Information Manual)
Ozone 0-0.1 ppm DT, Chemiluminescent meter  
Radon 4-200 pCi/L Radon Cartridge, Electrect  
VOC's (See OSHA Chemical Information Manual) (See OSHA Chemical Information Manual) (See OSHA Chemical Information Manual)