The Desk

Your connection to your work is through your hands. Place equipment on and around your desk so that when you perform routine tasks:

• Your shoulders are relaxed.
• Your upper arms are close to your body.
• The angle between your upper arm and forearm is in the range of 75° to 135°.
• Your wrists are bent no more than 5° right or left and no more than 10° up and down.

Adjustable Desk

Ideally, your desk should have an adjustable surface large enough to accommodate a monitor and a separate, adjustable keyboard tray. Adjustable desktops and keyboard trays allow for different operators and a variety of tasks to be performed.

Fixed-Height Desk

• A fixed-height desk can make using the computer uncomfortable. A desk that is low causes curvature of the lumbar spine, increasing the load. A desk that is too high causes abduction of the arms and forward flexion or elevation of the shoulder and neck muscle (a 15° bend at the neck is acceptable).
• If a fixed-height desk is used, add a keyboard tray that adjusts vertically . The minimum adjustment range for this tray should be 22" to 28" (56 to 71 cm) from the floor.
• Adjust your chair to a comfortable position, adjust the keyboard tray to allow you to type with the angle between your upper arm and forearm in the range of 75° to 135°, and your wrists bent no more than 5° right or left and no more than 10° up and down. Then adjust the monitor's support surface to allow you to gaze slightly down to view the center of the screen.

Desk Design

• Select a desk that is stable.
• Desktops should have a matte finish to minimize glare and reflection.
• Avoid sharp edges - rounded or sloping edges are preferable.
• Avoid glass tops - sharp edges compress the arm during writing tasks; Also, glass tops present a glare problem.
• From your desk's edge, the minimum under-desk clearance depth should be 15" (38 cm) (optionally, 17" (43 cm)) for your knees and a 23.5" (60 cm) for your feet. The minimum under-desk clearance width should be 20" (51 cm).
• The desktop should be large enough for work objects (at least 27.5 (70 cm) wide), and should prevent the sliding of these objects.
• The desk surface should be deep enough to provide at least 16" (41 cm) between your eyes and the monitor screen. If necessary, move the desk away from the wall to provide enough space between your eyes and the monitor screen.
• Under desk obstructions should be removed to provide sufficient leg room.
• Taller workers or workers with history of back pain may be more comfortable with a height-adjustable desk, a sit/stand desk, or a standing workstation. The minimum adjustment range for a keyboard tray on a standing workstation should be 34.5" to 47.25" (88 to 120 cm) from the floor.
• If your desk is too low, raise your desk by placing stable wood or concrete blocks under the desk legs or use a desk leg stand. If your desk is too thick for you to place your legs under the desk, remove a middle drawer or add a keyboard tray.

Source: Creating the Ideal Computer Workstation: A Step-by-Step Guide - United States Department of Defense, June, 2000.