Environmental Health and Computers:

Ergonomics and the Choice of Office Furniture

The Office of Environmental Health and Radiation Safety has provided ergonomic consultation services and training for Penn employees since 1993. As a result of our campus consultative program we have evaluated many different types of office furniture to understand which furniture designs work best as computer work stations.

The purchase of furniture is an important decision for an office because of its cost and impact on employee productivity and health. We offer the following information to guide you in the selection of new furniture for general office work. These guidelines may not be applicable to all office environments.

Workstations

A standard office desk should not be selected as a computer workstation. A typical office desk is 29 -30 inches high and this places the keyboard at a typing height that is too high for a large number of office workers. We recommend adjustable height furniture for computer workstations because the placement of the keyboard at the proper height for typing is critical for proper ergonomic positioning. The proper typing height depends on the worker's height as shown in the table below:

 

 Worker Height

 Table Height

 5'0" - 5'3"  25"- 26"
 5'4" - 5'6"  26"-27"
 5'7" - 6' 0"  27"-30"
 6'1" - 6'5"  30"-32"

The typing surface of adjustable height workstations can be raised or lowered to accommodate the needs of current and future workers.

User-adjustable workstations typically have a crank that changes the height of the typing surface (and in some instances the monitor height is also adjustable). The height may be adjusted without the need for disassembly, typically in a few minutes. User-adjustable workstations are ideally suited for locations that will have multiple users or a high rate of employee turnover.

Maintenance-adjustable workstations require disassembly to change the height of the typing surface. This type of workstation is usually adjustable in half or full inch increments.

Keyboard Drawers

EHRS does not recommend the purchase of workstations with keyboard drawers or articulated trays. Most keyboard drawers or trays are deficient in one of the following areas:

  • no provision for a mouse, or a mouse support that is too far away from the keyboard
  • trays that provide mouse supports are often wide and cumbersome when installed in small cubicles
  • hard or nonexistent wrist rest
  • trays limit leg room under the desk when pushed in

By design, keyboard drawers are not height adjustable, a critical requirement for proper workstation setup. Articulated keyboard trays require the user to set the proper height each time the tray is pulled out from under the desk. It is our experience that workers seldom bother to do this properly.

Other selection criteria to consider: The typing surface must be large enough so that the keyboard and monitor can be placed directly in front of the worker (the placement of the CPU is not important). A 30 inch deep typing surface is usually adequate for a 17" monitor (ISC's recommended configuration) and keyboard. Do not purchase 24 inch deep work surfaces for computer workstations. If you currently have a large (>17") monitor, or anticipate upgrading to one, select a deeper typing surface.

Work surfaces with rounded edges are preferable to those with sharp edges.

The layout of the workstation is important and may impact chair selection. Chair arms may bump into the desk with workstation layouts that are "L" or "U" shaped.

Avoid furniture with storage cabinets or book shelves above the typing surface. The shelves may make it impossible to place the monitor at the correct viewing height.

Furniture purchases are important investments for departments. If you plan to buy multiple workstations, insist on seeing an actual unit along with the chairs you have selected. Do not order out of a catalog sight unseen.

Contact Joseph Passante (898-4453, Joe@ehrs) if you have questions.

--Office of Environmental Health and Radiation Safety


Almanac, Vol. 45, No. 10, November 3, 1998

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