Office Ergonomics/Safety

Pamela A. BoatrightSystem Safety, Health & Environment Resource CenterOklahoma State Regents for Higher Education

Ergonomic Regulations OSHA published a draft ergonomic

standard, but it was not approved. However, the OSHA “General Duty

Clause” requires employers to provide a safe and healthy working environment for employees.

OSRHE Guidelines (4/98)

Ergonomics The study of the relationship

between man and machine. When the body is required to

perform repetitive motion, work in an awkward position, or repeatedly lift heavy objects, injuries may develop.

When employees are comfortable they are more productive.

Risk Factors Repetitive activity Holding a position without movement Use of force or strength Localized pressure Awkward positions (Low temperature) (Vibration)

Repetitive Activity Open letters Stapling Flipping through files Sorting letters Keyboard

Computer vs. typewriter

Holding Position w/o Movement

Reduces blood flow Fatigue

Work demands Gripping mouse too tightly Holding phone to ear

Excessive Use of Force Typist – up to 10,000 impacts

per day People diagnosed with carpal

tunnel use 18% more force to do a task

Excessive Use of Force Stapling Stamping Grasping large folders or books Lifting files/books Pushing/pulling heavy file drawer Chair “scooting”

Localized Pressure Sharp edges Keyboard corners Work surface corners Hard or angular chair arm rests

Awkward Positions Press on nerves, stretch tendons

Shoulder and phone Elbow and phone Poor neck postures, movements Leaning, reaching for tools (10-key,

printer, stapler, etc.)

Awkward Positions, Wrist Bending up, down, side-to-side

Inappropriate keyboard height Inappropriate keyboard angle No support for resting hands Splayed elbows Faulty keyboarding/mouse habits

Neutral Body Posture Places the least amount of

stress on the body Physical stress is evenly

distributed “Zero gravity posture” “Neutral position”

Neutral Body Posture Straight back 90° hip bend 90° knee bend Straight

head/neck Relaxed shoulders 90° elbow bend Straight wrists

Upright sitting posture The torso and neck

are approximately vertical and in-line

The thighs are approximately horizontal

The lower legs are vertical

Declined sitting posture Thighs are inclined The angle between

the thighs and the torso is greater than 90 degrees.

Torso is vertical or slightly reclined and the legs are vertical.

Standing posture The legs, torso,

neck, and head are approximately in-line and vertical.

The user may also elevate one foot on a rest while in this posture.

MSDs Carpal Tunnel Guyon’s Canal Epicondylitis Reynaud’s Thoraic Outlet Muscle Strains

Ganglion Cysts Tendonitis Tenosynovitis DeQuervain’s Trigger Finger Back Pain

Carpal Tunnel The channel found in the wrist

surrounded by bones and a non-elastic ligament.

Several blood vessels, nine tendons, and the median nerve all pass through this channel from the forearm into the hand.

Carpal Tunnel Certain movements, especially

repeated movements and bent wrists, can cause an increase in pressure in the carpal tunnel.

Symptoms can include tingling, numbness, pain, swelling, and burning sensation in the hand.

1-2 per 1000

Workstation Configuration

Workstation Configuration Chair Characteristics Keyboard and Mouse Monitor Position Glare Document Position Telephone Use Work Behavior

Chairs

Chair Position Back straight Head upright Fully supported S-

curve in spine Wrists straight Hips, knees and

elbows at 90° Feet and arms

supported

Examples of Good Chairs

Chair Characteristics Back rest covers from hip to upper

back Contoured and padded seat and

backrest Waterfall seat design Five casters for stability

Chair Adjustability Seat height Seat depth Tilt tension Back height Arm height

see slide out card under chairs, left forward side

Examples of Poor Chairs

Bad and Ugly Too!

Keyboards/Point Devices

Keyboard and Mouse Position

If you can’t lower the keyboard, you may

consider raising your chair. Center the alphabetical section to your body. Keep the keyboard flat. Rest wrists on rest pad only when not typing. Place the mouse next to the keyboard.

About 2-3” lower than desk height

Keyboard Positioning Place the keyboard directly

in front of you at a distance that allows your elbows to stay close to your body with your forearms approximately parallel with the floor.

A keyboard tray may be useful if you have limited desk space or if your chair has armrests that interfere with adequate positioning.

Wrist Rest Placement

Your hands should move freely and be elevated above the wrist/palm rest while typing.

When resting, the pad should contact the heel or palm of your hand, not your wrist.

Wrist Rest Placement

Some desks and computer equipment have hard, angled leading edges.

This can affect nerves and blood vessels, possibly causing tingling and sore fingers.

Typical Keyboards/Trays

Keyboard Tray Tilt 0° to -15° No + tilt angle Height Adjusts

6 1/4“ Base Swivel Locks

Alternative Keyboards

Keyboard Placement

Alternative keyboards help maintain neutral wrist postures, but available research does not provide conclusive evidence that using these keyboards prevents discomfort or injury.

Pointing Devices

Improper Mouse Placement

Mouse Wrist Rest

Alternative Pointing Devices

Good Working Positions | Workstation Components | ChecklistsGood Working Positions | Workstation Components | Checklists

Adjusting Computer Pointer Sensitivity and speed should feel

comfortable. The pointer should be able to cover the full

screen while the wrist is maintained in a straight, neutral posture.

Sensitivity should be set so you can control the pointing device with a light touch.

Most devices can be adjusted through the computer control panel.

Avoid tightly gripping the mouse or pointing device.

Monitor Position

Monitor Position Monitor in front of the

keyboard, not to side Top of monitor at eye

level Arm’s length away (24-

30” approx.) Up to 10° backward tilt

or flat Text size may need to

be increased for smaller monitors.

Monitor Position The top of the

monitor should be at or slightly below eye level.

The center of the computer monitor should normally be located 15 to 20 degrees below horizontal eye level

Monitor Position Monitor blocks

are simple and inexpensive.

Telephone books are cheaper.

Monitor Position

Bifocal Wearers Bifocal users typically view the monitor

through the bottom portion of their lenses.

This causes them to tilt the head backward to see a monitor that may otherwise be appropriately placed.

As with a monitor that is too high, this can fatigue muscles that support the head. 

Monitor Tilt Monitors that are tilted significantly either

toward or away from the operator may distort objects on the screen, making them difficult to read.

When the monitor is tilted back, overhead lights may create glare on the screen. This can result in eyestrain and sitting in awkward postures to avoid eye glare.

Monitor Solutions Lower the monitor so you can maintain

appropriate neck postures. You may need to tilt the monitor screen

up. Raise chair height until you can view

the monitor without tilting your head back. You may have to raise the keyboard and use a foot rest.

Use a pair of single-vision lenses designed for computer work. 

Other Monitor Considerations Adjust brightness as needed. Keep the screen clean.

Glare

Glare

Glare may cause eye strain or headaches.

Position the monitor between overhead lights and perpendicular to windows

Select a glare screen for the model and size of monitor, but only if needed.

Task lighting on the document should not cause glare on the monitor.

EMF “radiation” is NOT an issue.

Glare screens Block up to 99.9%

of ELF/VLF E-field radiation when properly grounded

$250 Glare only $130

Document Holders

Document Position Position documents

next to monitor and at the same height to reduce: Head and neck

movement Eye refocusing

distance

Document Holder

Allows you to place documents at or about the same height and distance as the monitor screen.

Should be stable when loaded with heavier documents such as a textbook.

Provides a sturdy writing surface, if written entries are necessary.

Work Zones

The location of frequently-used items should remain within the primary work zone.

Work Zones

Telephone Use

Telephone Use Place the telephone in the

primary or secondary work zone, depending on usage patterns.

Cradling the telephone between your neck and shoulder creates an awkward position. Avoid the shoulder-rest device if at

all possible. Consider a phone headset instead.

Telephone Quick Tips Use a speaker

phone or head set for long conversations.

Keep it close enough to avoid repeated reaching.

Work Behavior Eye relaxation techniques

Place palms over closed eyes and relax Focus on far away objects - “20/20 Rule”

Change tasks and/or position every 20 - 30 minutes. Allows muscles to recuperate from static

positioning Improves blood flow to extremities

Microbreaks (do NOT replace regular breaks)

Work Behavior High repetition tasks or jobs that require

long periods of static posture may require several, short rest breaks.

Users should stand, stretch, and move around to provides rest and this allows the muscles to recover.

Alternate tasks whenever possible, mixing non-computer-related tasks into the workday. This encourages body movement and the use of different muscle groups.

Lift CAREFULLY; never twist and lift

Workstation Assessments

Workstation Assessment

Limited space on the work surface may cause users to place components and devices in undesirable positions.

Workstation Assessment

No room for trackball on keyboard tray

No document holder

No wrist rest

Workstation Assessment Monitor too low Mouse position Keyboard position No arm rests Document holder

good

Workstation Assessment Poor mouse

position No document

holder

Workstation Assessment Monitor and

keyboard too high No arm support Document height

too low

Workstation Assessment Much better !! Lowered monitor Raised arm rests Raised chair

Conclusion All you need is common sense. Always work in neutral positions. Modify the equipment around you,

don’t modify your body posture to fit the equipment.

Give adjustments a couple of days. Minimize awkward postures, static

positioning, and repetitive movements.

Workstation Stretches

Developed by Dr. Houshand Seradge, M.D.

The Hand InstituteOrthopaedic & Reconstructive Center

1044 SW 44th StreetOklahoma City, OK 73109

405/631-4263

Laptop Ergonomic Guidelines

Centers for Disease Control and Prevention

Laptop Guidelines The CDC recommends that laptop

computers not be used as a primary computer at home or at work.

Occasional users should: Find a comfortable chair Use a neutral wrist position Position screen to minimize neck

bending

Laptop Guidelines Consider using an external keyboard or

docking station. Take mini-breaks ever 20-30 minutes. Keep viewing distance @18-30 inches. Position keyboard at elbow height. If seated in a side-chair or couch, use a

pillow to support your arms while keying. Clean the screen regularly.

Docking Stations

Transporting the Computer If computer and accessories > 10

lbs, consider a bag with wheels. Eliminate all unnecessary items

from your briefcase. Carry a laptop in a case with

padded shoulder pad and handle. Shift hands and shoulders to

balance the load.

Web Resources http://www.osha.gov/SLTC/etools/

computerworkstations/index.html http://www.osha.gov/SLTC/etools/

computerworkstations/positions.html http://www.osha.gov/SLTC/etools/

computerworkstations/checklist.html http://www.osha.gov/SLTC/etools/

computerworkstations/wkstation_enviro.html

Office Safety

Falls Falls are the most common office

accident. Clear walking pathway Close drawers after use Avoid bending, twisting, leaning while

seated Secure electrical cords

Struck By or Striking Objects Bumping into desks, cabinets,

open drawers Supplies falling out of cabinets or

off shelves Misbalanced file cabinets Machines dropped on feet Doors opening suddenly

Caught In or Between Fingers caught in drawer, door, or

window Fingers, hair, clothing, jewelry

caught in machines Fingers caught under knife or

paper cutter

Safe Office Practices Use a proper stepladder for

overhead reaching, not rolling chairs or even padded chairs, please.

Clean up spills immediately, even if they are not “yours”.

Report loose carpeting, damaged flooring, lights out, etc.

Office Electrical Safety Never remove the grounding

plug from any piece of equipment.

Inspect electrical equipment and electrical cords regularly. Repair or discard if damaged.

Electrical Cords Do not drape or pull over nails,

hooks, or other sharp objects. Extension cords are temporary

wiring only. If a cord must run across a walkway, tape it or cover it.

Never pull a plug to turn off equipment.

Electrical Cords

Working on “live” equipment Disconnect electrical machines

before cleaning or adjusting. If a guard is removed to clean or

repair parts, replace the guard before testing or putting it back in service.

“Daisy Chain”

Slip, trip, or fall

Electrical Cords

Overloaded Outlets