Ergonomic improvements are changes made to improve the "fit" between a job and the capabilities of the employees performing it. Making ergonomic improvements reduce physical demands, eliminate unnecessary movements, lower injury rates and their associated workers' compensation costs, and reduce employee turnover. When making improvements to ergonomic problems, we use one or more of the strategies in the "Hierarchy of Controls" (HOC). We encourage employers to use the HOC described in the ANSI/ASSP Z10, Occupational Health and Safety Management Systems.
The first three strategies focus on doing something with the hazard.
Elimination: The best solution is to totally eliminate the need to lift, lower, push, pull, or carry heavy loads. It may also be impossible to complete projects without placing workers in unusual postures, overreaching, or overexertion.
Substitution: Substitution is the next-best solution. For instance, the employer might replace large heavy containers with smaller containers.
Engineering Controls: Redesign or modify equipment and processes. For instance, processes that require heavy lifting, lowering, or carrying heavy objects might be revised.
The last three strategies focus on doing something with behaviors to reduce exposure to the hazard.
Warnings: Warnings may be visual, audible, or both. They may also be tactile. Visual warnings include signs, labels, tags, and lights. Audible warnings include alarms, bells, beepers, sirens, horns and announcement systems. Tactile warnings may include vibration devices or air fans.
Administrative Controls: The primary focus is to develop and incorporate safer behaviors and work practices through written safety policies and rules, supervision, and training. This strategy is a challenge because supervisors must regularly monitor their employees as they perform tasks. Bottom line, these controls work only so long as employees comply with safe practices.
Personal Protective Equipment (PPE): The use of PPE is probably the most common strategy use for all hazards. PPE forms a barrier between workers and hazards. For instance, knee pads might be used to protect the knees when laying carpet.
1. Which of the following hazard control strategies focuses on equipment design or redesign?
a. Engineering controls
b. Administrative controls
c. Elimination and substitution
d. Personal protective equipment
Since the science of ergonomics involves designing the job to fit the worker, let's look at engineering controls that improve the design of tools, equipment, and the work area to mitigate hazards.
Engineering improvements include rearranging, modifying, redesigning, or replacing tools, equipment, workstations, packaging, parts, or products. These design changes can effectively reduce or eliminate the underlying hazards that cause injuries.
Below are a few examples of how simple engineering controls can be used to reduce ergonomic injuries:
Use a device such as a dolly, forklift, or crane to reposition heavy objects to limit force exertion.
Reduce the weight of a load such as lumber to limit force exertion.
Reposition a work table to eliminate a long/excessive reach and work using awkward postures.
Use staple guns or roofing nailers instead of hammers to shingle a roof.
Use circular saws instead of handsaws to cut lumber.
Use augers instead of post hole diggers or shovels to dig holes.
2. Which of the following hazard control strategies is considered most effective in construction?
b. Administrative controls
c. Engineering controls
d. Personal protective equipment
Raise or lower the work surface or the employee. This reduces bending, reaching, and awkward postures. A rule of thumb is to try to keep your hands at about elbow height when
Use cut-out work surfaces to get closer to the work. This reduces visual effort and awkward postures.
Reposition the work to reduce bending and reaching.
Reconfigure the workstation so that sliding and rolling replaces lifting and carrying.
Use adjustable equipment that allows for a comfortable, upright working posture.
Provide close, convenient storage for frequently used materials, parts, or tools to reduce reaching and awkward postures.
Provide comfort: Foot rests, padding, and good lighting, all make work more comfortable.
Use lifting aids such as vacuum lifts, manipulators, mechanical lifts, workstation cranes, scissors lift, and automatic feed systems to reduce force, repetition, and awkward postures in lifting or handling tasks.
Use mechanical aids such as adjustable carts, conveyors, and powered transport to reduce force, repetition, and awkward postures in transporting materials and products over longer distances.
Storage and Retrieval of Materials
Provide adequate, well-lit storage with easy access to reduce repetitive reaching, bending, twisting, and forceful exertions. Use mobile, lightweight storage carts with adjustable trays. Tilted containers make access easier.
Increase the efficient use of storage space by grouping stored items by container size or shape.
3. Which of the following devices is best at reducing force, repetition, and awkward postures when transporting materials over long distances?
a. Lifting aids
b. Mechanical aids
c. Storage aids
d. Containment aids
Good design and proper maintenance can help reduce pressure points on the hands, awkward postures (e.g., bent wrists), forceful exertions, and other contributing factors.
This abrasive grinder is designed well.
Workers should not have to use their hands or bodies as a vise to hold objects; mechanical devices do this much better. Tooling fixtures and jigs should be set up to avoid awkward
postures and excessive forces.
Hand tools should fit the employee's hand; employees with small hands or who are left-handed may need tools designed specifically for these situations. When selecting and purchasing
hand tools, the guidelines listed below should be followed.
Select tools that allow the wrist to be held straight and that minimize twisting of the arm and wrist. Good working posture can be maintained when properly designed tools are used.
Select tools that allow the operator to use a power grip (uses all fingers to grip), not a pinch grip (uses only thumb and forefinger). Minimal muscle force is required to hold
objects in a power grip posture. The pinch grip requires excessive fingertip pressure, and can lead to a cumulative trauma disorder (CTD).
Avoid tools that put excessive pressure on any one spot of the hand (i.e., sides of fingers, palm of the hand).
For power or pneumatic tools, select tools with vibration dampening built in whenever possible. Provide personal protective equipment such as gel-padded gloves to reduce exposure
Use better, ergonomically-designed tools which may be lighter weight, require less force to operate, fit the hand better, and are more comfortable to use.
4. To reduce the force required to perform a task, select a tool that allows the use of a _____.
a. prolonged grip
b. pinch grip
c. power grip
d. left-hand grip
The power zone is above the knees, below the shoulders, and close to the body. Click to enlarge
Administrative improvements include changing work practices or the way work is organized. They may not address the reasons for the contributing factors or other problems. Administrative
improvements usually require continual management and employee feedback to ensure the new practices and policies are effective. Below are some best practices for the workplace:
Alternate heavy tasks with light tasks.
Provide variety in jobs to eliminate or reduce repetition using two primary strategies:
Job rotation - rotating employees through different jobs.
Job enlargement - increasing the variety by combining two or more jobs or adding tasks to a particular job.
Adjust work schedules, work pace, or work practices. Limit the amount of time any employee has to spend performing a "problem job." Job hardening suggests new workers who are not
used to the physical demands of the job should be gradually introduced to a normal work pace.
Provide recovery time - recovery periods (i.e., muscle relaxation periods) can help prevent fatigue and injury to muscles.
Modify work practices so that workers perform work within their midrange or power zone (i.e., above the knees, below the shoulders, and close to the body).
Require that heavy loads are only lifted by two people to limit force exertion.
Establish systems so workers are rotated away from tasks to minimize the duration of continual exertion, repetitive motions, and awkward postures. Design a job rotation system in
which employees rotate between jobs that use different muscle groups.
Staff "floaters" to provide periodic breaks between scheduled breaks.
Properly use and maintain pneumatic and power tools.
6. Which of the following would be considered an ergonomic administrative control measure?
a. Anti-vibration gloves
b. Adequate layered clothing during cold days
c. Padded handles on electric drills
d. Stretching prior to the start of work
Regular housekeeping to eliminate clutter can reduce reaching, bending, or twisting when handling materials, tools, or objects. Keep floor surfaces dry and free of obstructions to
help eliminate slipping and tripping hazards.
Regular maintenance of tools and equipment can help reduce or prevent problems in work tasks. For example, keeping cutting or drilling tools sharpened and in good condition can
reduce the amount of force and repetition required when using the tools.
Exercise and Stretching
Long-term, sensible exercise and stretching have many benefits, which may include better health and reduced injuries. New, returning, or injured employees should gradually increase
their physical activity.
Get help when needed to handle heavy loads. Some companies set weight limits (like 50 pounds) above which a helper is required
7. An administrative control to help prevent ergonomic injuries caused by exposure to hazards would include ____.
a. a preventive maintenance program with written procedures
b. overhead lights when intricate work is performed
c. gloves to reduce stress due to forceful movements
d. adjustable office chairs
Lifting can put a great strain on your back. Lifting from the floor can be particularly risky. For example, lifting a 25-pound box from the floor requires about 700 pounds of back muscle
force, even when you bend your knees. Below are some tips that can help protect your back when you need to lift heavy objects.
Try out the load first. If it is too bulky or heavy, get help.
Avoid lifts that require stretching or bending to reach the load. Redesign the work area so objects you lift are close to the body and at waist height.
Don't lift awkward objects such as long pipes or large boxes by yourself. Get help or use mechanical assists.
When lifting, keep your back straight and lift with your legs.
Lift slowly and carefully and don't jerk the load around.
Keep the load as close to your body as possible while lifting it.
Don't twist or turn your spine while carrying the load.
Make sure your path is clear while carrying the object. Remove obstacles that could cause you to trip.
The images below illustrate safe lifting techniques.
A program to teach workers how to lift properly should be used in combination with workplace redesign that reduces the amount of lifting needed. Remember, if materials are too heavy or
awkward to lift and carry safely, get help, redesign the materials to be lighter and easier to handle, or use mechanical assists such as hoists, carts, or conveyors.
8. Where should the load be placed with lifting?
a. At arm's length away from body
b. Close to the body
c. It doesn't matter where the load is
d. At shoulder level or higher
Safety gear, or personal protective equipment (PPE), includes gloves, knee and elbow pads, footwear, and other items that employees wear.
Gloves can protect hands from cold or injury. However, gloves may decrease manual dexterity and make it harder to grip if they do not fit correctly. Wear good fitting thermal gloves
to help with cold conditions while maintaining the ability to grasp items easily
Proper footwear and anti-fatigue soles can prevent employees from slipping and prevent fatigue from long hours of standing on hard surfaces.
Knee and elbow pads can protect the body from pressure points when pressing against hard or sharp surfaces
Back belts are not considered by OSHA to be acceptable for use as personal protective equipment. They may help maintain the proper curvature of the spine during lifting or physical exertion and may also provide comfort and confidence while performing work tasks. However, you can't lift heavier loads just because you're wearing a back belt because it doesn't actually support the lower back. If you use them all-day-every-day, your back muscles may actually get weaker.
9. Why does OSHA consider backbelts unacceptable for use as personal protective equipment?
a. Studies have not been conducted
b. They do not support the lower back
c. They work only while carrying small heavy objects
d. They are not made of approved materials
Conduct an Ergonomics Hazard Analysis to prioritize jobs.
You may want to choose specific improvement options for various tasks in your workplace. To best help prioritize the tasks who which you would like to improve, conduct job hazard analyses (JHA) that focus on ergonomics hazards. Some of the things you need to analyze include:
worker variables (fitness, age);
types of work (e.g., roofing, sheetrock, framing); and
the work environment (e.g., lighting, cold exposures).
To determine which tasks you want to address first, consider the following:
frequency and severity of complaints, symptoms, and injuries;
contributing factors or other problems you have identified in a task;
ideas your employees have for improvements;
difficulty of implementing various improvements;
your time frame for making improvements;
potential effects on productivity, efficiency, and product or service quality; and
technical and financial resources at your disposal.
10. What proactive process can best help prioritize the tasks to which you want to improve?
a. Job hazard analysis (JHA)
b. Accident investigation
c. Employee testing
d. Third-party audits
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