Paying attention to ergonomics pays off
Workplace ergonomics is getting a lot of attention nationwide in response to a sharp increase in incidents of repetitive strain injuries resulting in musculoskeletal disorders, such as carpal tunnel syndrome. Occupational diseases often mean repeated surgery, intractable pain, inability to work, time off for the affected employee, and, ultimately, higher costs for the employer.
Factors including work surfaces at the wrong height, uncomfortable chairs, shelves and bins that are too high or out of reach, and awkward hand tools, all contribute to increased risk of musculoskeletal disorders injury and may offer a negative impact on productivity.
There is a wealth of options available to adjust the workspace to meet employees’ ergonomic needs and selecting the right ones can help employees reap significant bottom line rewards. Paying attention to ergonomics means removing barriers to work productivity. Comfortable employees stay at their desks or work stations longer, and complete more work in a given shift. Employers who pay attention to these four simple steps are well on their way to gaining these rewards.
Ergonomics – designing the job to fit the worker
Ergonomics is the science of designing a job to fit the worker, rather than physically forcing the worker’s body to fit the job. By adapting tasks, work stations, tools, and equipment to fit the worker, ergonomics seeks to reduce physical stress on a worker’s body and eliminate many potentially serious, disabling work-related musculoskeletal disorders (MSDs).
If work tasks and equipment do not include ergonomic principles in their design, workers may have exposure to undue physical stress, strain, and overexertion, including vibration, awkward postures, forceful exertions, repetitive motion, and heavy lifting.
Step 1 – Review tasks for risk factors
The first step to correcting problems is to understand the key workplace ergonomic risk factors and review work tasks in your operation to see which ones apply. This can make a tremendous difference, since occupational safety professionals estimate that reducing physical stresses could eliminate as much as half the serious injuries that happen each year. Predicting what might go wrong and modifying tools and the work environment to make tasks safer for workers is the first step to reducing problems. Table 1 lists these key risk factors and notes the injuries each may cause.
Step 2 – Control risk factors with engineering and administrative controls, and personal equipment, where it is effective
Engineering controls, administrative controls, and personal equipment are the three key ways to control the risks identified earlier. Examine each of these to see how each may be used to control the risks identified in Step 1.
Engineering controls to improve ergonomic risks may include changing the way parts and materials are transported; changing the process to reduce how workers are exposed to risk factors; moving parts around to make it easier for workers to reach them; or changing work station layout, tool design, or access and assembly sequence.
Of equal impact are administrative controls, adjusting work practices and policies to reduce risk factors. Examples include rest breaks, job rotation, or training to identify signs of ergonomic stress.
Finally, personal equipment may be considered, including wrist supports, back belts, or vibration attenuation gloves. However, it should be noted that, although personal equipment may reduce the duration, frequency, or intensity of exposure to risk, their effectiveness in injury reduction is considered inconclusive by National Institute for Occupational Safety and Health (NIOSH). Figure 2 is an illustration of the general ways of reducing the risk factors identified in Step 1.
Step 3 - Understand how to make the work space work ergonomically
With any task, selecting the proper tool is crucial. The key is to understand the work process and employees’ safety needs involved. After identifying the likely risk factors in an operation, develop a safer work environment by carefully selecting the tools and work stations workers will use. Start the process by asking these questions:
- Does the work process involve handling heavy, bulky or awkward products?
- Is there a high product mix, with many product changeovers per day?
- Will work stations be integrated with material flow – with racks or conveyors, for example?
- Is there frequent job rotation, employees from different shifts or departments sharing a work area?
- Will employees work alone, back-to-back or in teams?
- Does a work station need to include power tools, computer equipment, supplemental lighting or storage space?
Issues frequently encountered include work surfaces that are the wrong size or at the wrong height; uncomfortable chairs; shelves and bins that are too high or out of reach; and awkward hand tools.
To counter these issues, it is important that employees can rearrange work station elements easily. Regardless of physical characteristics or the tasks performed, employees should be able to make adjustments to work surface height and chair seat height, or change the elevation of work shelves and work surfaces to increase worker comfort and productivity.
Step 4 – Use work station design principles to improve ergonomics
Table 2 lists general work station design principles, which include a range of considerations employers should use when designing work stations.
The most important principle to keep in mind is that work is handled most efficiently when kept within areas defined as “primary reach zones”. These are the horizontal and vertical areas that a worker can reach with minimal arm, head, or trunk movement. Moving away from these primary zones requires more movement, and ultimately more time. Ergonomic solutions & help keep most work tasks focused within these reach zones. Figure 3 illustrates this concept – what it shows is that work takes place within a 24 inch radius; everything else should be considered storage.
To minimize stress and strain for seated employees, the work station should be at the proper height to support the particular task being performed. Precision work usually requires a higher work surface, while heavier work demands a lower work surface. Generally speaking, a 30.5 inch work surface height will accommodate 99.5 percent of all male and 99.9 percent of all female workers.
But what if different shifts are using the same bench and/or what if different tasks are being performed on the same bench? If so, consider an adjustable-height work station. With such a bench, users can adjust the bench height with the simple turn of a crank or with a motor drive, and the work surface can move between approximately 27 and 38 inches. This would accommodate the height of the widest range of workers, from about 5 feet to 6 feet 8 inches.
Other considerations include convenient reach and accessibility to accessories, like hand tools, small parts, nuts and bolts, a comfortable and adjustable chair, foot rest, and proper lighting. A final consideration, and one that is becoming more and more important, is the location of computer monitors. It is important that they can be adjustable up or down to be at the employee’s eye level. With the rise of flat panel monitors, employers are finding swing arms a useful tool for properly positioning monitors to avoid strain. The use of a negative-tilt keyboard tray is also recommended for reducing wrist strain.
Case closed – ergonomic issues solved
Nonin Medical Inc. of Plymouth, Minnesota decided to pursue ergonomically preferable work stations as part of its lean manufacturing implementation. The company, which specializes in manufacturing precision devices that measure physiological variables such as oxygen levels and pulse rates, was seeking better access to tools and parts, greater flexibility to adapt to ergonomic challenges resulting from employees of different sizes operating the same workbenches, as well as improved lighting.
The company eventually chose LISTA’s Arlink 8000 Modular Work Station System, which is designed for extremely quick assembly and reconfiguration. The work stations can be configured in a variety of heights and lengths to suit unique needs. The patented Definite Positioning System® makes it extremely easy and fast to relocate and adjust work surfaces, storage, shelving, lights, power beams, and footrests, without requiring any extra tools.