Ergonomics And Safety In Hand Tool Design Pdf

Introduction to Workplace Ergonomics

Workplace ergonomics is the science of designing the workplace, keeping in mind the capabilities and limitations of the worker. Poor worksite design leads to fatigued, frustrated and hurting workers. This rarely leads to the most productive worker. More likely, it leads to a painful and costly injury, lower productivity and poor product quality.

A workplace ergonomics improvement process removes risk factors that lead to musculoskeletal injuries and allows for improved human performance and productivity.

By making improvements to the work process, you are removing barriers to maximum safe work performance. You are providing your workers with a job that is within their body's capabilities and limitations. And (as you'll see throughout this series) you'll be contributing to your company's bottom line.

Done well, an ergonomics improvement process can be a key contributor to your company's competitiveness in the marketplace and provide a better work experience for your people.

But where do you get started?

What are other companies doing with respect to ergonomics and what do their results look like? How can you find the time and resources to execute this process at your facility?

These are some of the questions you may be asking about ergonomics. We've put together this tutorial to help you answer these questions (and more) and to help you get your ergonomics process off the ground.

Benefits of Workplace Ergonomics

An effective ergonomics process can benefit your organization in a number of different ways.

The Value of Workplace Ergonomics
In fact, Washington State Department of Labor and Industries reviewed 250 case studies on the effects of ergonomics in a variety of settings. They found that ergonomics can have a profound impact on your organization, including the following five benefits:

1. Ergonomics reduces costs.

By systematically reducing ergonomic risk factors, you can prevent costly MSDs. With approximately $1 out of every $3 in workers compensation costs attributed to MSDs, this represents an opportunity for significant cost savings. Also, don't forget that indirect costs can be up to twenty times the direct cost of an injury.

2. Ergonomics improves productivity.

The best ergonomic solutions will often improve productivity. By designing a job to allow for good posture, less exertion, fewer motions and better heights and reaches, the workstation becomes more efficient.

3. Ergonomics improves quality.

Poor ergonomics leads to frustrated and fatigued workers that don't do their best work. When the job task is too physically taxing on the worker, they may not perform their job like they were trained. For example, an employee might not fasten a screw tight enough due to a high force requirement which could create a product quality issue.

4. Ergonomics improves employee engagement.

Employees notice when the company is putting forth their best efforts to ensure their health and safety. If an employee does not experience fatigue and discomfort during their workday, it can reduce turnover, decrease absenteeism, improve morale and increase employee involvement.

5. Ergonomics creates a better safety culture.

Ergonomics shows your company's commitment to safety and health as a core value. The cumulative effect of the previous four benefits of ergonomics is a stronger safety culture for your company. Healthy employees are your most valuable asset; creating and fostering the safety & health culture at your company will lead to better human performance for your organization.

Implementing a proactive ergonomics process presents you with an opportunity to add significant value to your organization.

Workplace Ergonomics Process

A proactive ergonomics process identifies ergonomic risk factors and then reduces them through engineering and administrative controls before an injury occurs.

Workplace Ergonomics Process

A world class ergonomics program is proactive and viewed as a strategic continuous improvement process that makes a positive impact on the entire business.

Conducting an ergonomic risk assessment in response to an injury isn't a bad thing to do. In fact, it's what you should do.

But that's a reactive approach, and if you keep doing what you've been doing, then you're going to keep getting what you've been getting — injuries. To wage a war on the MSDs at your facility, you'll need to get out in front of the problem by being proactive.

Remember that above all else, a world class ergonomics program is proactive and viewed as a strategic continuous improvement process that makes a positive impact on the entire business.

In other words, ergonomics shouldn't be an afterthought. If your ergonomics program is in reactive mode, it will only have a marginal impact on your facility at best.

Here is a deeper dive into the ergonomics improvement process we implement for clients:

Step 1: Prioritize Jobs for Ergonomic Analysis
This prioritized list should be developed by the ergonomics team based on an initial facility tour, review of MSD history and data collected by employee surveys.

Step 2: Conduct Ergonomic Analysis
This analysis will objectively measure risk for each job in the workplace and help you develop an ergonomic opportunity list.

Step 3: Develop an Ergonomic Opportunity List
Developing an ergonomic opportunity list allows you to prioritize company resources in order to effectively and efficiently reduce risk by putting the appropriate controls in place.

Step 4: Determine Best Solution with Team Approach
A multi-disciplinary team should be involved in determining the best controls for implementation.

Step 5: Obtain Final Approval and Implement Solution
If the improvement requires a significant capital expenditure, cost-justify the solution to gain approval.

Step 6: Evaluate the Ergonomic Improvement for Effectiveness
Once improvements are in place, close the loop on the project by evaluating the ergonomic improvement and measuring its effectiveness.

Ergonomic Risk Factors

Risk factors related to work activity and ergonomics can make it more difficult to maintain the balance between musculoskeletal fatigue and recovery, and increase the probability that some individuals may develop an MSD.

Ergonomics Risk Factors
The primary workplace ergonomic risk factors to consider are:

High Task Repetition
Forceful Exertions
Repetitive/Sustained Awkward Postures

1. High Task Repetition

Many work tasks and cycles are repetitive in nature, and are frequently controlled by hourly or daily production targets and work processes. High task repetition, when combined with other risks factors such high force and/or awkward postures, can contribute to the formation of MSD. A job is considered highly repetitive if the cycle time is 30 seconds or less.

2. Forceful Exertions

Many work tasks require high force loads on the human body. Muscle effort increases in response to high force requirements, increasing associated fatigue which can lead to MSD.

3. Repetitive/Sustained Awkward Postures

Awkward postures place excessive force on joints and overload the muscles and tendons around the effected joint. Joints of the body are most efficient when they operate closest to the mid-range motion of the joint. Risk of MSD is increased when joints are worked outside of this mid-range repetitively or for sustained periods of time without adequate recovery time.

Ergonomic risk factors increase musculoskeletal fatigue and introduce barriers to productivity and human performance.

Ergonomic Assessments

Applying a scientific, evidence-based approach to your ergonomics process is important. The goal is to identify ergonomic risk factors, quantify then, and then make measurable improvements to the workplace, ensuring that jobs and tasks are within workers' capabilities and limitations.

The best approach for doing that is to make ergonomics an ongoing process of risk identification and risk reduction based on objective, scientific analysis of your workplace.

These are the ergonomic risk assessment tools we recommend and use for clients. If you'd like, you can download step-by-step guides all of the tools at no charge here.

WISHA Lifting Calculator

Developed by the Washington State Department of Labor and Industries and based on NIOSH research related to the primary causes of back injuries, this lifting calculator can be used to perform ergonomic risk assessments on a wide variety of manual lifting and lowering tasks, and can be also used as a screening tool to identify lifting tasks which should be analyzed further using the more comprehensive NIOSH Lifting Equation.

Tool: Online WISHA Lifting Calculator

Training: A Step-by-Step Guide to the WISHA Lifting Calculator

Source: Washington State Department of Labor and Industries

NIOSH Lifting Equation

The NIOSH Lifting Equation is a tool used by occupational health and safety professionals to assess the manual material handling risks associated with lifting and lowering tasks in the workplace. This equation considers job task variables to determine safe lifting practices and guidelines.

The primary product of the NIOSH lifting equation is the Recommended Weight Limit (RWL), which defines the maximum acceptable weight (load) that nearly all healthy employees could lift over the course of an 8 hour shift without increasing the risk of musculoskeletal disorders (MSD) to the lower back. In addition, a Lifting Index (LI) is calculated to provide a relative estimate of the level of physical stress and MSD risk associated with the manual lifting tasks evaluated.

Tool: Online NIOSH Lifting Equation Calculator

Training: A Step-by-Step Guide to the NIOSH Lifting Equation (Single Tasks)

Rapid Entire Body Assessment (REBA)

This tool uses a systematic process to evaluate whole body postural MSD and ergonomic design risks associated with job tasks. A single page form is used to evaluate required body posture, forceful exertions, type of movement or action, repetition, and coupling. A score is assigned for each of the following body regions: wrists, forearms, elbows, shoulders, neck, trunk, back, legs and knees. After the data for each region is collected and scored, tables on the form are then used to compile the risk factor variables, generating a single score that represents the level of MSD risk.

Tool: REBA Ergonoimcs Software

Training: A Step-by-Step Guide to the REBA Assessment Tool

Source: Hignett and McAtamney, 2000

Rapid Upper Limb Assessment (RULA)

This diagnostic tool assesses biomechanical and postural load requirements of job tasks/demands on the neck, trunk and upper extremities. A single page form is used to evaluate required body posture, force, and repetition. Based on the evaluations, scores are entered for each body region in section A for the arm and wrist, and section B for the neck and trunk. After the data for each region is collected and scored, tables on the form are then used to compile the risk factor variables, generating a single score that represents the level of MSD risk.

Tool: RULA Ergonomics Software

Training: A Step-by-Step Guide to the RULA Assessment Tool

Source: McAtamney & Corlett, Applied Ergonomics 1993, 24(2), 91-99

Liberty Mutual Manual Material Handling Tables (Snook Tables)

The Liberty Mutual MMH Tables (commonly known as Snook Tables) outline design goals for various lifting, lowering, pushing, pulling, and carrying tasks based on research by Dr. Stover Snook and Dr. Vincent Ciriello at the Liberty Mutual Research Institute for Safety. The tables provide weight/force values, for specific types of tasks that are deemed to be acceptable to a defined percentage of the population. This is done by comparing data for each of the specific manual handling tasks against the appropriate table.

Tools: Snook Tables Software Tools

Training: A Step-by-Step Guide to the Snook Tables

Source: Liberty Mutual Research Institute for Safety

Washington State Ergonomic and MSD Risk Assessment Checklist

This tool is designed to evaluate ergonomic risks factors including awkward postures, highly repetitive motions, high hand force, repeated impacts, lifting, and hand-arm vibration. The Caution Zone Checklist is used as a screening tool. If there are no positive findings identified, the job is regarded to be safe; otherwise a moderate risk is indicated and the job should be evaluated further using the Hazard Zone Checklist. Positive findings with the Hazard Zone Checklist indicate immediate actions should be taken to reduce the risk.

Caution Zone Checklist [PDF]

Hazard Zone Checklist [PDF]

Source: Washington State Department of Labor and Industries

Workplace Ergonomics – Control Method

After ergonomic opportunities are prioritized, it's time to determine the best engineering or administrative controls to implement.

This process takes a team approach. Information and input should be gathered from affected employees, members of the safety and/or ergonomics team(s), supervisors, and process managers and/or engineers to determine the best solution to the problem that has been identified.

All potentially affected job tasks, work processes, and employees should be fully considered when contemplating physical changes and control measures. It's important to ask and consider how any proposed engineering controls will affect the entire process, both upstream and downstream.

Engineering Controls

Engineering controls eliminate or reduce awkward postures with ergonomic modifications that seek to maintain joint range of motion to accomplish work tasks within the mid-range of motion positions for vulnerable joints. Proper ergonomic tools should be utilized that allow workers to maintain optimal joint positions.

Administrative Controls

Administrative controls establish processes and procedures that can reduce injury risk. Administrative controls include work practice controls, job rotation, and counteractive stretch breaks.

Control Methods to Consider for High Task Repetition

Engineering Controls – Eliminating excessive force and awkward posture requirements will reduce worker fatigue and allow high repetition tasks to be performed without a significant increase in MSD risk for most workers.

Work Practice Controls – Providing safe & effective procedures for completing work tasks can reduce MSD risk. In addition, workers should be trained on proper work technique and encouraged to accept their responsibilities for MSD prevention.

Job Rotation – Job task enlargement is a way to reduce duration, frequency and severity of MSD risk factors. Workers can rotate between workstations and tasks to avoid prolonged periods of performing a single task, thereby reducing fatigue that can lead to MSD.

Counteractive Stretch Breaks – Implement rest or stretch breaks to provide an opportunity for increased circulation needed for recovery.

Control Methods to Consider for Forceful Exertions

Engineering Controls – Eliminating excessive force requirements will reduce worker fatigue and the risk of MSD formation in most workers. Using mechanical assists, counter balance systems, adjustable height lift tables and workstations, powered equipment and ergonomic tools will reduce work effort and muscle exertions.

Work Practice Controls – Work process improvements such as using carts and dollies to reduce lifting and carrying demands, sliding objects instead of carrying or lifting, and eliminating any reaching obstruction to reduce the lever arm required to lift the object.

Proper Body Mechanics – Workers should be trained to use proper lifting and work techniques to reduce force requirements.

Control Methods to Consider for Awkward Postures

Engineering Controls – Eliminate or reduce awkward postures with ergonomic modifications that seek to maintain joint range of motion to accomplish work tasks within the mid-range of motion positions for vulnerable joints. Proper ergonomic tools should be utilized that allow workers to maintain optimal joint positions.

Work Practice Controls – Work procedures that consider and reduce awkward postures should be implemented. In addition, workers should be trained on proper work technique and encouraged to accept their responsibility to use their body properly and to avoid awkward postures whenever possible.

Job Rotation – Job rotation and job task enlargement is a way to reduce repeated and sustained awkward postures that can lead to MSD.

Counteractive Stretch Breaks – Implement rest or stretch breaks to provide an opportunity to counteract any repeated or sustained awkward postures and allow for adequate recovery time.

Further Reading:

A Step-by-Step Guide to Job Rotation
Workplace Stretching and Warm-up: Benefits of a Work Readiness System

Ergonomic controls are most effectively prioritized, cost-justified, and implemented by a multi-disciplinary ergonomics team.

Additional Resources

Get more ergonomics tools and training.

The Ultimate Guide to Workplace Ergonomics

The Definition, Domains, and Applications of Ergonomics

Workplace Ergonomics and Injury Prevention Guidelines by Industry

8 Fundamental Ergonomic Principles for Better Work Performance