Choosing the Right Furniture

The locations of your keyboard and monitor depend on the table or desk that supports them; that, combined with the importance of the chair that supports your body, means you should think seriously about the furniture that you use with your computer. Rather than just placing the computer on a convenient space on your desk (or your kitchen counter) and pulling up the nearest chair, think about the height and distance between your body and the machine, and support for your back and your arms.

Table or work surface

Begin with the table, countertop, desk, or other work surface that holds your computer; whichever you choose, this surface should be dedicated to the computer. Don't try to squeeze the monitor, mouse, and keyboard onto an already cluttered space, because it will probably force you to adopt an awkward position to use the computer.

The work surface should be deep enough to place the monitor screen at least 20 inches (50 cm) from your eyes, with the screen directly in front of you. As mentioned earlier in this chapter, remember to keep the screen perpendicular to your line of sight (don't place the screen at an odd angle). You need additional clearance behind the screen if you're using a monitor with a CRT screen; if necessary, you can often create more room for a CRT monitor by moving your desk or table away from the wall.

Caution

Don't try to make more room for a big CRT monitor by placing it in a corner, unless you can place your chair and your keyboard in a position where you're looking directly at the screen. Don't put it in a place where you have to twist your neck or tilt your head to see the screen.

The keyboard and mouse should fit comfortably under your hands, with your wrists at the same level or slightly below your elbows. This allows the height of the surface to be closely related to the height of your chair. If you can't raise and lower the chair, find a way to adjust the height of the work surface.

Underneath the surface, you should have open space for your feet and knees without obstructions. In other words, your knees should not bump up against a solid horizontal or vertical surface. If the surface is too low for you, consider placing the desk on solid risers (such as wood blocks), or remove the center drawer from a traditional desk to create additional clearance. If it's too high, raise your chair, and use a footrest to support your feet.

In general, the height of a work surface for a keyboard and mouse should be about four inches lower than a typical desk designed for reading and writing, so the ideal office workstation often has a split surface or a separate adjustable tray for the mouse and keyboard.

Chairs

The function of any chair, especially a chair used for work, is to support your upper body without placing any more strain on your spine than absolutely necessary. It should also provide support for your arms at the correct height and position for operating a keyboard.

A chair used at a computer workstation should have these elements:

A seat at the right height to let you keep your feet on the floor or on a footrest, and your knees slightly higher than the seat of the chair. The seat should be wide enough to accommodate your hips, and deep enough to let you change your posture over time.
A backrest that supports the shape of your spine as you change position. In most cases, this means a chair with adjustable lumbar (spinal column) support that fits the small of your back, and which allows you to lean back at least 15 degrees from vertical. As you lean back, the chair should support the weight of your upper body. The relative positions of the back and the seat should let you sit with your spine against the backrest without hitting the inside of your knees against the front of the seat.
An armrest that can support your lower arms (below the elbows), while keeping the upper part close to your body and your shoulders relaxed . Your wrists should be at about the same level as your elbows or a little lower. The armrests should be comfortably padded with no sharp edges.
A base that provides solid support, regardless of your position. The best office chairs have five horizontal legs to prevent tipping , with casters that allow you to move around the floor.

The height of your chair depends on the height of your keyboard and your monitor. If you're sitting in front of a raised drafting table or counter, you should use a stool with a footrest at the correct height to keep your knees at or slightly below your hips and your forearms level.

They're rare, but you might find a chair or stool that has all of these elements in exactly the right places to fit your body. If you find such a wonder -chair, buy it. But don't count on finding that chair. Because people come in so many sizes and shapes , most chairs for computer workstations offer adjustable settings for height, back support, and armrests. If possible, try sitting in a chair before you buy it and try more than one type before you make a decision.

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Choosing the Right Furniture