David R. Carson

Soft-copy reading rooms present unique challenges to designers of specialized PACS furniture. Multiple monitors and keyboards and

a mouse (or several) require a special focused approach to create the least stressful, most comfortable, and most productive work environment for radiologists and physicians.

Ergonomic workstation design can be tailored to an individual of nearly any size. But any design for multiple users whose specific physical needs are unknown or may change as personnel change is typically pointed toward accommodation of the 5th percentile seated female user to the 95th percentile standing male user. Ergonomic performance benchmarks should follow this accepted practice.

"Human factors" is a term used by ergonomic designers in describing the interactions among humans and other elements of a system. The Human Factors and Ergonomics Society (HFES) is an organization of engineering professionals in academia and industry who consult, conduct research, and apply established ergonomic principles to a wide variety of manufactured products and workplace procedures. HFES published the original American National Standard for Human Factors Engineering of Visual Display Terminal Workstations (ANSI/HFS 100-1988), which was accepted by the American National Standards Institute in 1988. In 2002, HFES published the first revision to the original standard-BSR/HFES 100-which is expected to be submitted soon to ANSI for final adoption.

HFES represents the highest level of expertise and the lowest potential for conflicts of interest. It offers the most current ergonomic standard in the world. ANSI/HFES guidelines address the physical relationship between the user and the computer equipment regardless of where they are located: in an office, hospital, clinic, or factory.

A soft-copy reading room is a specialized office application, with multiple users, multiple monitors, central processing units, and so on. It requires an intense need to focus on ergonomics and the productivity, health, and safety of the user. The proposed ANSI/HFS 100 standard includes the following key requirements:

- Monitor height positioning. A 15 degrees to 20 degrees downward view angle from horizontal eye level to the center of the monitor screen is recommended to minimize neck, shoulder, and back problems.

- Monitor placement. Monitors should be placed in a manner that attempts to achieve equal focal lengths to lessen the need to refocus when looking from screen to screen. A horizontal view angle as close to perpendicular to the screen as possible will minimize distortion and reflection.

- Monitor focal length adjustment. All monitors should be adjustable fore and aft simultaneously, approximately 12 inches, to meet individual visual requirements.

- Input surface positioning. The input surface should be adjustable from the 5th percentile seated female elbow height to the 95th percentile standing male elbow height to achieve natural arm and shoulder positioning and neutral wrist alignment.

- Knee and leg clearances. Obstructions in the knee space must be avoided, and clearances should meet ANSI/HFES 100 guidelines.

Other factors to be considered include "green" construction to assure indoor air quality and personal environmental control of light levels, airflow, and temperature.

Indoor air quality is an issue that must be addressed by architects, designers, and manufacturers of furnishings and equipment. Nine states have already mandated green construction for public buildings, and the U.S. General Services Administration has indicated it will be adding indoor air quality requirements to its furniture specifications.

Individual personal control of light levels (dimming), air flow, and temperature at the workstation holds the potential for greater employee satisfaction and productivity and a corresponding rise in the number of images read and the quality of interpretation.

"Tuning" of the workplace to fit the physical needs of each individual user, adjustability to fit a wide range of potential users, improvement of indoor air quality, and accommodation of personal environmental control all combine to form a package of elements that, together, are designed to enhance the performance of the most valuable component of the enterprise: the highly educated, highly compensated physician.

David R. Carson

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National standards group tackles workstation design