Home Office Ergonomics

Ergonomics is a science receiving widening attention. The Ergonomics Society in London defines it as “the study of the relation between man and his occupation, equipment, and environment, and particularly the application of anatomical, physiological, and psychological knowledge to problems arising therefrom.” Most of the physical pain being experienced results from the fact that most office furniture is not sufficiently adjustable to fit the different sized workers who use a standard piece of office furniture.

Anthropometrics, the measuring branch of anthropology, is a part of ergonomics that can help. People do not come in the same size, even two persons sharing the same height and weight. To know what adjustments are needed in office furniture, we must determine the range of anthropometric variations to accommodate.

statistics from the National Aeronautics and Space administration (NASA) cover a wide spectrum of nations and races around the world. These statistics show that arm reach, for instance, can vary as much as 10.6 in., eye height (sitting) as much as 9 in., knee height as much as 8.8 in., and sitting height as much as 10.1 in. Similar variances exist for almost every body part, and these dimensions do not necessarily correlate well for any individual. In fact, numerous studies firmly establish that there is no such animal as the “average man.” So office furniture must be adjustable to fit the many differences among us.

Research reported by International Business Machines identifies a new problem that affects the coice of a chair: many terminal operators do not assume the expected posture of the typical typist. They assume the posture of a person driving a car, with the back of the chair at an angle of 105[deg. to 120[deg. to the seat instead of the expected 90[deg. . Because of this posture, chairs for terminal operators should have backs at least 20 in. high, and the action of the chair back with the seat should permit the needed 120[deg. angle between them. Also, due to this reclining posture, the adjustments of the height of the keyboard must increase in range, as well as those for the terminal itself.

Two recent studies confirm the importance of adjustable computer furniture.

* Dr. Marvin Dainoff and his associates at NIOSH (National Intitute of Occupational Safety and Health) did a study of productivity using IBM, Synergetic and Wrightline adjustable workstations compared to non-adjustable workstations. The project abstract says in part “preliminary results indicated a 24-1/2% improvement in performance as well as a decrease in musculo-skeletal complaints attributed to good ergonomic design characteristics.”

* A second study, conducted by Dr. T. J. Springer in the offices of the State Farm Mutual Automobile Insurance Company, also compared adjustable computer furniture to conventional, non-adjustable office furniture. He found that “improvements in performance were observed for each of the alternative work station designs. The NKR and IBM work stations resulted in a 15% improvement in data entry performance and a 10% improvement in dialogue transactions.” Criteria for terminal work tables

More than a dozen manufacturers are offering terminal work tables designed specifically to offer needed adjustments and features. These adjustable work tables are also ideal for word processors and “smart” typewriters; but, since the sizes of the surfaces vary from manufacturer to manufacturer, the size of the surface should be matched to the size of the machine.

The recommendations that follow are those of the author. These are not set rules, since so much more research needs to be done. They are, however, based on some 42 studies conducted by scientists in the U.S., Switzerland, Japan, England, Germany, Sweden, France, Finland, and Belgium. There may be a day in the not-too-distant future when the relatively cumbersome electronic equipment we now use is replaced by smaller, more versatile hardware. Until then, even the impermanent electronic office must bear some semblance of permanence from time to time.

Rapid advances in information processing technology make it an elusive target for designers of even the most highly adaptable open plan furniture systems. The problem stems from fundamental differences between the two industries. Information processing is still a young business creating new products with high added value that quickly supersede all predecessors. Office furnishings must be characterized as a mature business whose products do not differ sharply in overall performance and thus do not embody the high added value that would justify frequent redesign and innovation.

* Panel hung, freestanding, and casters refer to basic structural characteristics of the computer terminal work station. Panel hung work stations are assembled from parts of an open plan furniture system; their work surfaces for computer terminals and other business machines are almost infinitely adjustable, though changes may require partial dismantling of the work stations. Free-standing work stations are discrete pieces of furniture or assemblages of furniture systems components that resemble traditional furniture. Casters are sometimes available to give the computer terminal a high degree of mobility; whether or not this is desirable depends on the corporate user.

* Separate keyboard and terminal surfaces: as already discussed, this feature accounts for anatomical differences in eye height when sitting, arm reach, and other significant measurements.

* Keyboard height adjustment range should probably be from 22-1/2 in. To 33 in. There is quite competent research that indicates that this surface should be as thin as possible to leave room for the knee and lower limb.

* Terminal height adjustment range should probably be from 22-1/2 in. to 33 in., though there are terminal surfaces on the market that adjust as high as 41 in.

* Keyboard slides horizontally, toward or away from operator, in a range of 7 in. to 8 in. Again, this is for anthropometric reasons.

* Keyboard surface tilts, preferably as much as 15[deg. .

* Terminal surface tilts, ideally [plus-or-minus 7[deg. , though one table on the market provides for a tilt of -5[deg. to +25[deg. .

* Terminal surface swivels if the terminal is to be shared by other operators. Some manufacturers make small, portable visual display terminal(VDT) stands that tilt and swivel. These can be used on terminal tables or standard desks.

* Matte finish laminates available should be combined with proper colors and patterns to reflect 30% to 50% of the light they receive. Laminate manufacturers can furnish this information. Medium oak, teak, and light walnut usually fall within these guidelines, as do typical office grays and beiges. Dark walnut and rosewood are too dark, and contrast too much with white paper, becoming distracting. White laminate is too light. Its lack of contrast with white paper causes eyes to wander.

* Auxiliary surfaces available fit onto the sides of the terminal table. Some adjust in height in the same ranges as the terminal works surface. Other terminal surfaces are large enough so that no auxiliary surfaces are needed.

* table adjustment can be accomplished by a number of mechanical devices powered by electric motor, gas cylinder, or hand.

* Adjustable document holder available is becoming a necessity for many businesses.

* Table for hard copy printer is designed to hold both the large machine that prints hard copy and the equally bulky folded computer print-out paper that must be fed to it.

* Other business machines, such as the telephone, facsimile, tabletop copier, and dictating machine, are not nearly as specific in their need for proper housing as computer terminals and hard copy printers. As things now stand, these other machines can be accommodated by a wide range of office furniture not specifically designed for electronics.