Most of us tend to think of computer ergonomics as an office issue, with plenty of good guidance available about how the human operator works with desks and chairs and the computer boxes that sit on them. That, however, isn’t always the case.
Computers are not just for the traditional office anymore. The U.S. Census Bureau states that half of all adults use computers in their workplace, that three-quarters of all school age children use computers and that half of us have computers at home. While the basic principles of human computer interaction remain valid in office and non-office settings, computer ergonomics for non-office spaces requires us to think a little creatively.
Take a walk around any factory and you’ll see production line workers routinely using computers to track production data at the individual product level or to perform a quality or function test. Visit a hospital and you’re likely to see a physician or nurse charting notes electronically, perhaps even in the patient’s room. What you won’t see, however, is the traditional desk and chair workstation arrangement. Computer users are as likely to work standing as they are to work seated. Space is in short supply and valuable.
Often, the exact place where good ergonomic practice tells us that the keyboard or monitor should be located during use is, in non-office environments, needed for other equipment. Ultimately, the computer display and input devices need to be able to move out of the way. Compounding the situation the fact that non-office computer workstations are much more likely to be shared workstations.
While many offices have become dedicated computer workspaces, the non-office environment generally has to be more adaptable and able to accommodate variation among users, more variation in user postures and more pressure to share space in the workplace. Computer furniture will often need to fold up, swing back and forth, and move up and down to allow other work to be performed within the same footprint on the plant floor or to allow egress in a small workspace, like those found in hospitals.
Because computer components such as monitors and input devices are generally added to a desk in an office workspace, we tend to think of them as though they were always fixed to the desk. But technical standards such as BSR/HFES 100 offer separate sets of recommendations and adjustment guidelines for both, typically keyed to elbow-height for input devices and to eye-height for displays.
Fortunately, the distance between an individual’s eyes and elbows is constant for a given posture. By keying on this difference, we can think about designs for non-office workstations that quickly accommodate individuals ranging from 5th percentile females to 95th percentile males whether they are seated or standing.
The following are some concepts and values I propose for use when setting up computer workplaces in non-office settings.
- Eye height*: In round numbers, eye height varies between 41 and 51 inches for seated workers and 56 to 69 inches for standing workers.
- Elbow height*: In round numbers, elbow height varies between 22 to 28 inches for seated workers and 36 to 45 inches for standing workers.
- Eye-elbow height difference: Whether seated or standing, this distance is the same. For a U.S. population, that difference ranges from just less than 19 inches (5th percentile female) to slightly more than 23 inches (95th percentile male).
- Gaze angle: The general recommendation is to place the monitor so that the top of the viewing area is at or slightly below the user’s horizontal eye level, which places the center of the screen at the ideal 15