Workplaces and workstations should fit the people who do the work so they can do their jobs to the best of their abilities and without unnecessary hindrances. An athlete might be able to clumsily run a mile in bowling shoes three sizes too big, but nobody would expect that athlete to be able to break any speed records doing it. The same philosophy applies to the workplace. We can"t expect to achieve 100 percent of our performance capabilities when the design of the workplace equipment will not allow each person to reach his potential. When we work to improve ergonomics in the office, we work to enable maximum performance.
We have all heard of ergonomics described as a way to fight cumulative trauma disorders. If you doubt that ergonomics can produce many other benefits, consider the following. Could you expect the highest possible quality and productivity, for example, in an office with hard-to-read computer monitors or where hands and wrists get sore after a few hours? Would employee morale, turnover and absenteeism be at their lowest when workstations are uncomfortable and the office is full of unnecessary noise and glare?
Office ergonomics is the study and modification of the office workplace to best fit it to the needs and requirements of the workers. The basic posture of each employee is considered in relation to his workstation, as well as other factors that increase fatigue, create distractions or reduce productivity (such as glare, noise and poor temperature control). Modifications are then made to make the workstation fit the needs of the worker. This enables maximum performance through reduction of wasted motion and unnecessary stresses. A side benefit is commonly a reduction in work-related cumulative trauma disorders.
When properly implemented, the benefits of ergonomic modifications can include reduced turnover, improved morale, less time lost due to medical visits, increased productivity, better quality, and less absenteeism. In examining workstations, look for the following optimal conditions:
Lighting: Indirect light should provide enough illumination to read small print easily, without glare when looking around the office or at monitor screens. Stopgap measures, such as glare-reducing screens on monitors, are not required when lighting is well designed.
Monitor easily readable: Screen brightness level should be adjusted to about equal the light level reflected from surroundings and the monitor picture should have no distortion or wasted space around the outside of the viewing area. A good monitor will have a bright, clear picture that is easy to read against the background. Lighting and surfaces to the back of a monitor should be no brighter than the monitor screen. Extremely bright backgrounds, such as windows or desk lamps, should be covered or dimmed.
Monitor position: Height should be set to eye level so that the worker"s head will be balanced while looking at the monitor, with the head centered over the keyboard to eliminate neck twisting. The monitor should be angled to reduce glare, if possible. Only minimal angling of the head, if any, should be required to look at the monitor. The top edge of the monitor screen will generally be at eye level, as a starting point. A desktop is usually too low by itself to support a monitor, so a low monitor can be set on old phone books or a stand to raise it. Laptop screens are always too low, so an accessory monitor can be used.
Document position: Documents should be at the same distance from the eyes as the monitor, located near the monitor, and adequately lit. Generally, we spend much more time looking at the document than at the monitor, so it should be most centrally located. A document holder mounted next to the monitor in a central position is useful for people who type from written notes or forms. A good one has a full back to support the document to keep it from flapping in the office air currents.
Keyboard position: The keyboard should be low and, usually, will be angled in a range from level (zero angle) to "downhill" (negative angle) to achieve a neutral wrist angle. The front of the keyboard should be smooth and rounded. The keyboard should be low and close to the body, rather than at a distance that requires stretching out the arms. Proper keyboard height for most people will be a few inches above their legs, so a desktop is seldom a good place for a keyboard. A special keyboard tray or a computer table with a low top is usually necessary to hold a keyboard at a good height. The optimum keyboard position will allow straight wrists, horizontal forearms and vertical upper arms while typing without reaching or reliance on wrist pads.
Mouse position: When the keyboard is at a good position, but the mouse is far away on desktop, the worker can have wrist trouble due solely to mousing. The often overlooked, but important, mouse should be at the same level as the keyboard if the mouse is used regularly. Wrist pads, especially the gel type, might help in conjunction with a good low and close position. Mouse bodies can put pressure on the carpal tunnel that can be reduced by a wrist pad. The optimum mouse location will usually be low and close to the body.
Desktop and other furniture: The desktop should be large enough to accommodate everything that is needed during a typical day. Files that are commonly used should be easily accessible from the chair, and at a comfortable height. Commonly used items should be centrally placed on the desk, with rarely needed items in the corners (such as pen cups, calendars or personal photos). Mailboxes should be placed according to amount of daily use. For example, if the mailbox is only accessed once or twice a day, it can be put on a nearby file cabinet or credenza. The area under the desk should be clear of storage and tangled cords.
Chair position: The chair should allow good whole-body posture, especially hand and wrist posture at the keyboard. The back of the chair should give the lumbar region effective support without accessory pads (many of which are too thick to work properly). Adjustable chair backs should not rest on the base of the chair, as there usually should be a 3- to-5-inch gap between the lower edge of the back and the base. The chair should be fastened together so that the base, back and legs are not wobbly. The seat base should be level. Padding should be firm enough that it does not fully compress when the worker is seated on it. The chair should be covered with a material that provides some grip when sitting in it. Wheels should turn easily and steer freely, and the chair should be on a hard floor or base so it rolls easily.
Foot and leg position: When the chair is at the correct height, both feet should rest flat on floor with thighs not pressing on the edge of the seat base. An elevated footrest is suggested where short legs do not allow this. A good footrest has some height adjustability and a gripping surface on part or all of the top. Foot massager beads make some footrests more desirable than others.
Ventilation: Cold or hot air should never blow directly onto individuals. Air in the building should not be stagnant. Noise from the starting and stopping of HVAC blowers should not be noticeable.
Noise: Street-level noise should not be discernible in the office. Acoustics should be such that telephone conversations do not carry from one workstation to another. Noisy machines, such as copiers and electric staplers, should be located away from workstations. (Copiers also draw traffic, leading to more social visits than usual and distracting the individuals who work near the copiers. Ozone generation from a copier can be substantial. Ozone, in even low concentrations, is quite hazardous, but the effects of working near copiers over long periods are as yet not determined. Considering noise and traffic alone, the optimum placement for copiers is in a separate, well-ventilated room).
Employee responsibilities: Employees should know how to keep their equipment in a proper state of adjustment. When typing, fingers should lightly touch the keyboard, not pound the keys. The hand should never be used to hammer on any surface or object. Damaged equipment that exposes the hands to more pressure, due to sharp edges, should not be used. Employees should get adequate rest in their off-hours to compensate for work stress, and they should avoid hobbies and side jobs requiring repetitive motion.
Employees should not buy and wear "drugstore" wrist braces without close medical supervision.
Employees should be aware of extra risk factors for cumulative trauma disorders, such as obesity, pregnancy, non-occupational repetitive activity, previous hand or wrist fracture, rheumatoid arthritis, hypertension, diabetes, thyroid disorders, kidney disorders, alcoholism, use of oral contraceptives, previous gynecological surgery or disorders and aging.
Employees should know useful stretches and practice them periodically while working. Employees should keep their back pockets free of thick items, such as large wallets or pocket notebooks, when sitting to keep the pelvis level. Employees should not sit on top of one leg, cross their legs for long periods or slouch low in their chairs, which can degenerate disks in the spine. Employees should exercise and stay in good condition, where practical.
Remember, no matter how many ergonomics modifications are made, there is no guarantee that cumulative trauma disorders will not occur. There are many other factors besides workstation design that contribute to the occurrence of these disorders. Good ergonomic design helps reduce the possibility of CTD substantially, but can never totally eliminate it when jobs are highly repetitious, as is keyboarding. However, fitting the office workplace to the individuals who work there can greatly reduce the chance of CTDs, while improving morale, productivity and quality to maximize individual performance.
William H. Kincaid, P.E., CSP, is a senior loss control consultant with Lockton Insurance Companies. Prior to joining Lockton, he was a corporate director of safety and health for a packaging manufacturer with multiple locations and worked nearly six years as an OSHA safety engineer, specializing in ergonomics, "significant cases," and fatality inspections in manufacturing and construction. He has a B.S. in mechanical engineering from Washington University in St. Louis.