Office Ergonomics and OSHA
Cecilia R. Aragon
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UC Berkeley
Spring 2006
Acknowledgments
• Jeffrey Chung, Lawrence Berkeley National
Laboratory ergonomics program manager
• Cathy Rothwell, US Navy ergonomics program
manager
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OSHA - Occupational Safety and
Health Administration
• Occupational Safety and Health Act of 1970
• Purpose:
– setting standards
– conducting workplace inspections to ensure
that employers are complying with the
standards and providing a safe and healthful
workplace
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Who is Covered by OSHA?
• In general (with some exceptions), all employers
and their employees in the 50 states, the District
of Columbia, and Puerto Rico.
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Who is Covered by OSHA?
• All employers and employees except:
– Self-employed persons
– Farms at which only immediate members of the
farmer's family are employed
– Working conditions regulated by other federal
agencies under other federal statutes. This category
includes most employment in mining, nuclear energy
and nuclear weapons manufacture, and many
segments of the transportation industries.
– Employees of state and local governments (unless
covered by an OSHA-approved state program)
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OSHA Standards
• Employers must protect workers on the job.
• Employers have the responsibility to know relevant
standards and comply.
• Compliance may include providing personal protective
equipment for employees.
• Employees must also comply with OSHA rules and
regulations.
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“General Duty” Clause
• The general duty clause of the OSH Act [Section
5(a)(1)] states that each employer "shall furnish .
. . a place of employment which is free from
recognized hazards that are causing or are likely
to cause death or serious physical harm to his
employees."
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Federal OSHA Requirements
• Access to Medical and Exposure Records
– Employers must grant employees access to medical records and
records on employees’ exposure to toxic substances.
• Personal Protective Equipment
– Employers must provide employees at no cost personal protective
equipment (e.g. protective helmets to prevent head injuries in
construction and cargo handling work, eye protection, hearing
protection, hard-toed shoes, special goggles, etc.)
• Hazard Communication
– Employers must conduct hazard evaluation of the products they
manufacture or import. If hazardous, containers of the material must be
labeled and accompanied by a material safety data sheet (MSDS).
Employers must train their employees to recognize and avoid material
hazards.
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Federal OSHA Regulations
• Recordkeeping
– Every employer covered by OSHA who has more than 10 employees,
except for certain low-hazard industries such as retail, finance,
insurance, real estate, and some service industries, must maintain
OSHA-specified records of job-related injuries and illnesses.
• Reporting
– Each employer, regardless of number of employees or industry
category, must report to the nearest OSHA office within 8 hours of any
accident that results in one or more fatalities or hospitalization of three
or more employees.
• Posting
– Post prominently the OSHA poster (OSHA 3165) informing employees
of their rights and responsibilities.
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State Programs
• States with OSHA-approved job safety and
health programs must set standards that are at
least as effective as the equivalent federal
standard.
• Most of the state-plan states adopt standards
identical to the federal ones.
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Cal/OSHA Responsibilities
• Enforce California laws and regulations
pertaining to workplace safety and health
– The Cal/OSHA Enforcement Unit conducts inspections of
California workplaces based on worker complaints,
accident reports and high hazard industries.
• Provide assistance to employers and workers
about workplace safety and health issues
– The Cal/OSHA Consultation Service provides assistance
to employers and workers about workplace safety and
health issues, and develops educational materials on
workplace safety and health topics.
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For More Information
• OSHA
– http://www.osha.gov
– http://www.ehso.com/oshaoverview.php
• Cal/OSHA
– http://www.dir.ca.gov/dosh/dosh1.html
– http://www.dir.ca.gov/occupational_safety.html
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Ergonomics
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What is Ergonomics? er·go·nom·ics \, ûrg-go-'näm-iks
‘Ergonomics’ is derived from two Greek words
Ergon meaning work
and
Nomos meaning principles or laws
Ergonomics = The Science of Work
Ergonomics is not a new science, although the term has
become more common lately. The phrase was first coined
in 1857.
[Rothwell]
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What is Ergonomics? er·go·nom·ics \, ûrg-go-'näm-iks
Common Definitions
“Ergonomics is essentially fitting the workplace to the
worker. The better the fit the higher the level of safety
and worker efficiency.” Fitting the Task to the Human ~
Grandjean 1990
“Ergonomics removes barriers to quality, productivity and
human performance by fitting products, tasks, and
environments to people.” ErgoWeb.com
[Rothwell]
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What are the consequences
of poor ergonomics?
• Why are we hearing about ergonomics now? Are
there new hazards at work? No!
– Consequences of poor workplace design were first documented
in the 17th century.
• Have you ever heard of these?
– Historic Occupational Disorders - house-maid’s knee, washer
woman’s thumb, writer’s cramp, data-processing disease,
clergyman’s knee, nun’s bursitis, weaver’s bottom, dustman’s
shoulder, tailor’s ankle
[Rothwell]
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Do these historic occupational
disorders still exist? Yes!
• They are part of a broad category of injuries and disorders
called Musculoskeletal Disorders (MSDs). MSDs are not usually
caused by acute trauma, but occur slowly over time due to repetitive
injuries to the soft tissues (muscles, tendons, ligaments, joints, cartilage)
and nervous system.
• MSDs can happen to anyone from office workers and
industrial employees to athletes and hobbyists.
Before
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Improved
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Do these historic occupational
disorders still exist? Yes!
• Work-Related Musculoskeletal Disorders
(WMSDs) are MSDs that are caused or made worse by
work methods and environment. They occur when the
physical capabilities of the worker do not match the
physical requirements of the job.
• Common MSDs:
– Tendonitis, Epicondylitis (Tennis or Golfer’s Elbow), Bursitis,
Trigger Finger, Carpal Tunnel Syndrome, Back Strain
[Rothwell]
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Before
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Improved
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What are aliases for WMSDs?
• Work-related MSDs go by many other names:
–
–
–
–
–
Repetitive Strain or Stress Injury (RSI)
Repetitive Motion Injury (RMI)
Cumulative Trauma Disorder (CTD)
Overuse Syndrome
Activity-related Pain Syndrome
Ergonomics can help prevent MSDs that are caused or aggravated by
working conditions
[Rothwell]
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MSDs
•
•
•
•
•
•
•
Carpal Tunnel Syndrome
Cubital Tunnel Syndrome
Tendonitis and Tenosynovitis
Trigger Finger
Epicondylitis
De Quervain’s Tenosynovitis
Wrist Ganglion Cyst
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Tendonitis
• Normal tendon glides smoothly in a tendon sheath
• When under pressure, the capillary flow to the sheath
is temporarily interrupted.
• When blood supply returns, swelling occurs.
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Double Crush Syndromes
• Multiple points of pressure will have cumulative effects
on axonal flow.
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Carpal Tunnel, Inside of Wrist
• Inside view of right wrist
• Yellow nerve crosses
under flexor retinaculum
• Nerve has to share the
space with nine tendons
and tendon sheaths.
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Median Nerve (Carpal Tunnel)
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Should Employers Care About
Ergonomics?
Average 2003 cost for LBNL computer-related workers’
compensation claims: $23,745.
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Office Ergonomics
• The science of "designing the job to fit the
worker, not forcing the worker to fit the
job."
• Ergonomics covers all aspects of jobs:
 physical stresses placed on joints,
USER
muscles, nerves, tendons, bones, etc.
 environmental factors affecting hearing,
vision, and general comfort and health.
EQUIPMENT


Enhance comfort
Increased productivity

Improve job satisfaction and morale

Reduced musculoskeletal discomfort,work
injuries/illnesses
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TASKS
ENVIRONMENT
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WORK CULTURE
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Designing for the Worker
• Anthropometrics
– branch of ergonomics that deals with the
measurement of body dimensions
– anthropometric data is used in the design of
equipment and products to make them fit the height
and reach of “most” of the potential population
– Gaussian distribution, design to 5%
• Consider range of size, age, and physical ability
when designing
– Americans with Disabilities Act (ADA)
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Adjustability
• Anthropometrics - designing for middle 50%?
• American airplanes vs. the Russian Sukhoi
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Ergonomic Risk Factors
• Awkward
positions
• Static postures
• Repetitive
motion
• Forceful
exertion
• Contact
pressure
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At Risk Thresholds
Per OSHA, certain situations create MSD risks:
•
•
•
•
•
Performing same motion pattern every few seconds
for > 2 hours continuously or 4 hours daily.
Maintaining non-neutral (unsupported, static/fixed or
awkward posture > one (1) hour continuously or four
(4) hours daily.
Forceful hand exertions > two (2) hours daily.
Unassisted frequent or heavy lifting
Boredom and monotony
Do you have these risks?
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Warning Signs
• Watch for:
 Tingling or numbness in hands
 Pain: sharp, dull or burning
sensation
 Stiffness, reduced range of
motion in arms, wrists
 Clumsiness, loss of grip strength
or coordination
 Visual fatigue, watery eyes,
dryness.
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Three Stages of CTDs
Stage One

aches and tiredness during working hours

symptoms settle overnight or days off work

no reduction in work performance

condition may persist for weeks or months and is reversible
Stage Two

symptoms start early in work shift and don’t settle overnight

sleep may be disturbed

capacity to perform repetitive work is reduced

condition usually persists for months
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Three Stages of CTDs
Stage Three

symptoms persist even at rest

pain occurs with non-repetitive movements of
affected area

sleep is disturbed

person unable to perform even light duties and has
difficulties with other manual tasks
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Workstation Setup: Neutral Posture
1. Use a good chair and sit back
2. Top of monitor 2-3" (5-8 cm)
above eyes
3. No glare on screen
4. Sit at arms length
5. Feet on floor or footrest
6. Use a document holder
7. Wrists flat and straight
8. Arms and elbows close to
body
9. Center monitor and keyboard
in front of you
10. Use a negative tilt keyboard
tray
11. Use a stable work surface
12. Take frequent micro-breaks
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Workstation Setup: Neutral Posture
Other Office Items
• Telephones
• Staplers
• Staple removers
• Letter openers
Work within your normal
range of motion
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• Hole punches
• Pens for writing
tasks
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Sitting Risk Factors
Neutral
Posture
Slumped
Posture
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Posture and Spinal Stress
lbs
660
Load on 3rd Lumbar Disc in 155pound male
550
440
330
220
110
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Reaching/Range of Motion Factors
• Elbow
• Arm/Wrist
• Shoulder
• Back
• Elbows in
• Face the
object you are
reaching for.
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Watch the Hand Movements
DON'T rest
your wrists
on the
desktop
DO let your
wrists float
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Watch the Hand Movements
SAFER
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Contact Pressure
Soft tissue compression
(muscles, nerves & blood vessels)
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Ergo Accessories - Chair
Features:
•
•
•
•
•
Height
Seat pan
Backrest height
Backrest tilt
Armrest height
- Armrest width
(chairs may have none, some, or all
of these).
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Ergo Chairs & Accessories
Features/Adjustments:
• Height
• Seat pan (width/depth)
• Backrest height
• Backrest tilt
• Backrest tension
• Armrests
• Casters
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Monitor Accessories
• Screen height at eye
level (exception:
bifocals and trifocal
lens wearers).
• Screen distance
about arms length
away.
• Room lighting -avoid
backlight, shadows or
reflective glare.
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Keyboards and Accessories
Voice-activated
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Input Devices - Pointing Devices
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Telephone Use
• Phone evaluation: reach,
placement, call frequency vs.
duration, multi-tasking, etc.
• Cradle with neck/shoulder
• Cordless unit / motorized unit
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Document Holders
Place hardcopy beside or in front of monitor to
reduce neck twisting.
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Notebooks, Laptops, Etc.
 Laptops can cause:
• Awkward arm position
• Neck flexion to view the screen
• Neck pain from carrying/transporting laptops
 Fixes:
• Use docking station and external input devices.
• Acquire portable devices and accessories.
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Potential At-Risk Condition(s)?
Guidelines: Shoulders relaxed/arms close to body side; safe
reaching distance for mouse; neutral sitting
 Right hand on mouse even
when not actively mousing
(median nerve).
 Left lean supporting body
weight with arm; spine out
of natural alignment
 Ulnar nerve compression
(non-mousing elbow)
 Static muscle loading: right
shoulder abduction, wrist
extension, flexed left arm
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Potential At-Risk Condition(s)?
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Potential At-Risk Condition(s)?
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Ergonomic Hazards - Before
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Ergonomic Controls - After
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Ergonomic Hazards - Before
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Ergonomic Controls - After
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Computer Workstation Considerations
Layout
Document Use
Lighting
Writing
Chair
Laptop
Work Surface
Work Style
Monitor and Vision
Input Devices
(keyboard and pointing)
Task Breaks
Telephone Use
Discomfort
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Individual Issues
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Computer Workstation
• Order of adjustments is important
– Adjust chair first
– Then adjust keyboard
– Finally, adjust monitor
• No single “right” way to sit
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