Ergonomics: Engineering Heath and Safety

Ergonomics Affects Our Quality of Life

At work, at home, and at play, ergonomics is changing the way we perform physical tasks and the way manufacturers design their products. Ergonomics continues to improve our quality of life, productivity, and comfort. Picture yourself driving a 1960's automobile. Vehicles 35 years ago had straight-backed bench seats and fixed steering wheels. Today, carmakers design automobiles keeping human needs in mind by applying ergonomic principles. Now imagine yourself sitting in a 1995 luxury sedan. Your back is surrounded by full lumbar support; you have almost infinite adjustability in the power seat, tiltable steering wheel, and climate control; dials are easy to read; and frequently used switches are comfortably within arm's reach. Which car leaves you feeling less stiff and tired after driving across the US? Today's cars are clearly more comfortable. However, if you answered "neither," you may be correct. Being comfortable during a long automobile trip relates to the comfort attainable in the work environment.

Ergonomics = Comfort and Savings

Although the 1990's cars and workstations are designed with more comfort features, you need training and education to maximize your comfort for daily use. The education encompasses:

Every machine, including the human body, has limitations. If it is used within its capabilities, it is very effective for which it was designed. Using your body beyond its capabilities or limitations increases the chance of a breakdown or the risk of injury. You don't drive a farm tractor across the US or plow a field with a Cadillac. By applying ergonomic principles, you can improve the comfort and safety of your work environment, while reducing the risk of injury and increasing productivity. Businesses benefit from the reduction of work-related injuries. Substantial savings can be realized through fewer medical and lost-time claims, lost work days, and lower workers compensation insurance premiums. One company realized a 79% reduction in lost-time incidents by implementing an effective ergonomics program (Rooney & Morency, 1992).

Why CTDs Occur

Work-related injuries such as CTS and tendonitis have made the word "ergonomics" more commonly heard in the 1990's. The widespread use of computers since the mid 1980's and the evolution toward job specialization have resulted in increased employee reports of musculoskeletal discomfort, pain, and disabling injuries in the workplace. The alarming increase in CTDs, as illustrated in the Bureau of Labor Statistics Data, has prompted Occupational Safety and Health Administration (OSHA) to develop an ergonomics standard, due in 1995. CTDs are costing businesses an estimated $27 billion annually. Businesses can benefit financially from implementing an effective ergonomics program that reduces the risk of CTDs and improves employee health and safety.

Many employees sit at their workstations eight hours a day, using a computer or assembling integrated circuits on a production line. Our bodies alert us through discomfort and pain that we are designed to be active, not stationary. Instead of resting, our muscles are constantly working to overcome the forces of gravity to maintain a sitting posture. Ergonomics enables employees to be more comfortable despite the sedentary nature of their jobs.

Ergonomic Improvements in the Workplace

When dealing with people who have injuries, ergonomic principles are applied to the "nth" degree. Every incremental improvement can make a significant difference to someone injured: being able or unable to work. For the purposes of this article, discussion is limited to non-injured employees and the general population.

Every workplace is typically composed of three elements:

Most people divide ergonomics into either office or industrial fields when, in fact, both share the same risk factors. For instance, nonmanufacturing facilities, such as an insurance company, have areas of material handling and production. Processing premium checks is material handling, and generating statements is production. However, the recent ergonomic focus has been on the computerized office due to the increased incidence of CTDs, litigation, and legislation. Class-action liability suits are pending against keyboard manufacturers and companies whose employees have experienced health problems in the computerized office.

In the 1980's office, employees were assigned the same height desks and unadjustable chairs, regardless of their individual heights. Job titles dictated the amount of work space available and the quality of furnishings. The clerical staff, who sat at their desks eight hours a day, were provided with poorly padded "task" chairs. Has it changed in your workplace yet? Progressive employers are now designing the job, the workstation, and the work space to match the employee's physical characteristics, job requirements, and comfort needs.

Hidden Hazards

Risk factors common to the three work areas are referred to as "hidden hazards," as opposed to the readily visible hazards associated with traditional injuries (i.e., slip/trip/fall). Identifying and reducing these risk factors can decrease the number of injuries and improve worker comfort and productivity. How do you identify these "hidden hazards" and potential risks? How do you modify the work environment?

Here are some areas to consider.

Excess Force

Does the job require strength beyond the capabilities of an employee? How is a load handled? Is it lifted, carried, pushed, or pulled? Is it a static or dynamic load? What is the weight and size of the load? Does it require a hand or a finger grip? Minimize the force required. Place the load close to the employee.

Excess Angle

Does the job force the employee to work using awkward motions? Wrist, hand, arm, shoulder, neck, and back positions should be as close to neutral as possible.

Excess Repetitions

Office workers once developed what was known as "tennis elbow." It was not from playing tennis, but from handling papers, reaching and bending the elbow between the desk and the attached 90 degree desk return. This motion is high in repetition, but low in force.

Encourage employees to examine their work areas, keeping the space organized and efficient. Minimize all non-value-added repetitions. A marathon runner chooses the lightest footwear for the race. A 3-ounce difference means the runner will lift an extra 8,500 pounds by the end of the marathon.

Poor or Sustained Static Posture

Poor posture is formed over months or a lifetime, due to inadequate furnishings or bad habits. It stresses and strains the body. Sustained static posture is any prolonged posture in which the muscles are in continual use to maintain that posture. Whether you are sitting or standing, some muscle group is statically holding your body in that posture, unless you are in a gravity-free environment. Muscles are designed for intermittent (periodically relaxed or vigorously exercised) rather than continual use. For example, typists must hold their arms up to type at a keyboard. This is continual use of the upper back and shoulder muscles. Muscles contract, decreasing the blood flow in this region as well as to the arms and hands. Blood vessels constrict, reducing oxygen supply and waste removal, resulting in fatigue.

When muscles fatigue over time, discomfort and pain may develop, leading to musculoskeletal problems. To reduce fatigue and discomfort, the upper extremities (i.e., elbows, arms, and hands), back, and feet should all be supported, as close to the body's neutral position as possible. Alternate between dynamic and static activity whenever possible. To vary your posture, try sitting, standing, or a combination; avoid sustained twisting or bending of the spine. Avoid work that requires awkward bending and twisting.

(Illus. taken from OSHA document # 3123)

Environmental Conditions

Certain environmental factors can cause additional physiological stress on workers. Some factors can be controlled, including heat, cold, fresh air, glare, noise, and vibration. Others are difficult to both quantify and control, such as psychosocial stress, which relates to negative organizational values including job stress, job security, gender and culture barriers, excessive work load, deadline pressures, and lack of managerial support. When designing a job or workstation, consider the employee characteristics of age, gender, body size and proportions, strength, endurance, fitness, disabilities, language and culture barriers, and safety procedures.

Time and Duration

Does the employee perform a variety of tasks, getting up and down frequently? Or does the employee sit at one station and do the same work all day long, stepping away only during designated breaks? Can the employee be cross-trained or the job enlarged to include a variety of tasks? Focused repetitive jobs dramatically increase job stress and the physical stress to a particular muscle-tendon group.

Initial Investment

Ever hear of "The 1, 10, 100 Rule"? Product changes cost $1 in the design stage, $10 in the fabrication stage, and $100 after the product is in the customer's hands. Factor in the human element when determining the criteria for purchase or design. Engineer it right the first time. If you don't, and an employee is hurt, the medical claims alone can become costly. CTS cases average $30,000 each!

If new workstations are designed for the employees and their job functions, the resulting ease of operation increases comfort and productivity. Even the best-designed workstations require minor adjustments as employees begin to use their new space; furnishings, papers, or tools may need rearranging to meet individual work styles.

An Ounce of Prevention

There are benefits for engineers trained to recognize, prevent, and correct hidden ergonomic hazards when designing jobs and workstations. In purchasing equipment, tools, or workstations, if the human factors --- the operators who use them --- are considered, the design should minimize the risk of employee injuries.

If the intended user or purpose of the space is unknown, workstations are best designed with some flexibility for adjustment and furniture placement. Adjustment modifications down the road will cost more than incorporating them in the design stage. Flexibility does not mean that you need movable furniture with instantaneous adjustment with the touch of a paddle lever or foot pedal. (Multi-user workstations dictate movable furniture. A person with an injury may also benefit from having this flexibility. The amount of flexibility each person and workstation requires must be analyzed individually; ergonomic consultants may be helpful.) It means, for example, that the work surface can be changed within a range of heights, rather than being permanently fixed at one standard height.

Ergonomics is TQM

It's all simply about doing it right the first time, whether it's designing a new workstation or modifying an existing one. It is easier and more cost-effective to prevent CTDs than to correct the situation after the discomfort and pain become a disabling illness. Remember: The more comfort provided for the employee, the less likely the risk of injuries. Ergonomics provides comfort, improves health, safety, and morale, and ensures profitability.

Achieving Comfort on the Road or at Work:

References

A Practical Evaluation Method for Quantifying Ergonomic Changes at L. L Bean; Implementing Ergonomics with Total Quality Management; E.F. Rooney and R.R. Morency; in Advances in Industrial Ergonomics and Safety IV; Edited by S. Kumar; Taylor & Francis, Inc.; Philadelphia; 1992; pp. 475-482.

A Methodology to Implement and Validate Ergonomic Improvements to Computer Workstations at L.L. Bean; R.R. Morency, E.F. Rooney, and D.R. Foerster; in Advances in Industrial Ergonomics and Safety V; Edited by R. Nielsen and K. Jorgensen; Taylor & Francis, Inc.; Philadelphia; 1993; pp. 263-266.

Fitting the Task to the Man; Etienne Grandjean; 4th Edition; Taylor & Francis, Inc; Philadelphia; 1988; pp. 12, 62, 70, 73, 76, 77, and 81.

About the Author

Karen Tai Morency is a corporate officer of R&D Ergonomics, Inc., a manufacturer and retailer of office and custom occupational ergonomic products that have assisted thousands of injured workers in returning to work. She is also the president of KTM Engineering & Services, which specializes in ergonomic consulting and training. She holds a BSME from the University of Maine. She combines engineering problem-solving skills and hands-on ergonomics knowledge to define affordable and practical workstation, work site, and work process solutions.

For more information, contact

R&D Ergonomics, Inc. 6 Harvey Brook Drive Freeport ME 04096-9622 TEL/FAX 207-865-6445 Email Us info@MorencyRest.com Author shown sitting at an ergonomically sound workstation with a monitor stand and forearm support from R&D Ergonomics, Inc. 

Glossary of Terms:

Ergonomics means matching the physical environment with the person in that environment. Ergonomics considers an individual's physiological, anatomical, and psychosocial capabilities and limitations within the work environment, including the tools, machines, and equipment.

Cumulative Trauma Disorders (CTDs) or Repetitive Strain Injuries (RSIs) are work-related illnesses or injuries resulting from musculoskeletal strain caused by repetitive exertions. These injuries are most common in the shoulders, arms, and hands; for example, Carpal Tunnel Syndrome (CTS). CTDs associated with computer use may become the biggest cause of occupational illnesses in history, according to the Congressional Office of Technology Assessment.

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