The seat back allows the operator to assume a comfortable position with ample support for the lower back. Arm rests, if present, have a minimum inside distance between them which is at least equal to the width of the hips of the operator. Adjustable seat pans, seat backs, and arm rests, if present, are readily operable by the operator without the use of tools. The topmost line of the VDT screen is slightly below eye level with the operator in an upright position. The operator while sitting in a comfortable position can perform keying with the torso sitting in an upright position.
Operators wearing bifocals or trifocals can look at the screen without tilting the head.
The keyboard, seating and work surfaces are positioned so that the operator, while seated in the most comfortable upright position, can perform keying with the keyboard approximately at elbow level, and the forearms, wrists and hands in a straight line approximately parallel to the floor. The work surface is high enough underneath so that it does no contact the top of the operators legs whenever the operator is sitting at the VDT with the feet flat on the floor or flat on a footrest. Input devices are positioned on the work surface at approximately the same height and distance from the operator at the keyboard. Input devices, primary work materials and frequently used accessories are positioned on the work surface in front of the operator. Adjustable screens, keyboards and work surfaces, if present, are readily operable by the user without the use of tools.