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VDT Workstation Design Guidelines

VDT Workstation Design Guidelines

The diagram presents the image of a user-friendly workstation. In the following paragraphs you will find detailed information on what makes a workstation ergonomically safe, including key features of a desirable workstation and some suggested solutions for modifying unhealthy conditions.

Following the recommendations below, users should fine-tune all of the adjustments to make the workstation as comfortable for them as possible. Costs for modifying workstations range from minimal to several hundred dollars. The least expensive solution may be as effective as a more expensive one, provided it allows the user to assume a safe and comfortable posture.

Newly purchased workstation furniture and accessories must minimally meet ANSI Standard (ANSI/HFS 100-1988 or revised versions). Workstation furniture and accessories that meet the ANSI Standard are available through Facilities Management. Departments should request outside vendors to verify that workstation furniture meets the ANSI standard prior to purchase.

Keyboard/Mouse Height

The height of the keyboard and mouse should allow the user to sit with shoulders relaxed, elbows bent, and forearms, wrists, and hands approximately parallel to the floor. The keyboard angle should be adjusted to promote a neutral/flat position of the wrists. This may be achieved in a number or combination of ways, such as:

  • a bi-level table easily adjustable for screen and keyboard height
  • a lower or higher table that promotes a straight wrist while keying (ie., a table height approximately two inches below the user's elbow)
  • a height-adjustable keyboard tray that can be attached to existing desk or table and provides both the appropriate keyboard/mouse height and adequate leg room for the user
  • a mouse tray
  • a chair that is height-adjustabl (may need to provide footrest)
  • a keyboard that is detachable from the monitor and adjustable for angle

Screen Height

The top of the display screen should be approximately at, but no higher than, eye level; lower and possibly closer for bi-focal wearers. The user should not have to assume awkward neck postures to view the screen or hard-copy documents. Retrofitting options include the following:

  • bi-level table adjustable for screen and keyboard height
  • baise monitor by putting it on top of hard disk drive, boxes, or books
  • lower monitor by removing it from the hard disk drive or other platform
  • adjustable monitor arm

Firm Posture Support

Chairs should firmly support a comfortable posture, providing support to the lower-back region and avoiding pressure on the back of the thighs. Retrofitting may include a number or combination of options such as:

  • chair adjustable for height and tilt of seat pan and backrest. VDT users should be able to adjust chairs from seated position without use of tools
  • armrests, if provided, should be height adjustable or removable to avoid interfering with natural movement of the arms
  • lumbar-support cushion if chair does not provide adequate lower back support
  • seat cushion or seat wedge
  • footrest if VDT user's feet do not rest firmly and comfortably on the floor

Wrist Support

Wrist rests may be helpful in promoting a neutral/flat position of the wrists. Retrofitting options include:

  • padded, movable wrist rest, same height as keyboard home row
  • a cushioned mouse pad

Accessories

Workstation accessories can prevent awkward neck positions. Accessories that should be provided if needed include:

  • document holders adjustable to screen height for users who type from hard copy documents
  • lightweight telephone headsets for users assigned to continuous telephone work in conjunction with VDT use

Lighting

Overhead lights, windows, or other light sources may contribute to visual discomfort. It is generally recommended that room lighting for use of VDTs with dark background screens be lowered to about half of normal office lighting. External sources of light (windows, overhead lights, etc.) should not be in the visual field of the VDT user, nor should their reflections be visible on the screen.

Temporarily shield peripheral light sources from view with a file folder. If this provides relief, try to eliminate the bright source in one of the following ways:

  • Use blinds or curtains over windows when necessary.
  • Position monitor screen at right angle to window.
  • Turn off some overhead lights; use task lighting, if needed.
  • Remove every other fluorescent bulb, if necessary.
  • Position monitors to avoid direct light in user's eyes.

Screen Reflections

Reflections on the screen reduce text visibility by decreasing screen contrast. Turn off the computer and look for bright reflections on the screen. Eliminate these reflections in one of the following ways:

  • Position monitor to avoid direct light on user's screen.
  • Use blinds or curtains over windows when necessary.
  • Position screen between banks of overhead lights.
  • Position monitor screen at right angle to window.
  • Make cardboard glare hood for top of monitor.
  • Use glare screen (glass preferred).