Help with Board Question and Unit Assignment. APA Format Throughout to Include Reference Page.
Board Question
What qualities make an effective ergonomics team? Why are those qualities so important?
Unit Assignment
In the Unit Lesson, we presented the problems that Amy is facing in her current workstation. Amy, who works as a cashier in a big-box store, works 8-hour shifts but is often asked to work overtime for up to 4 hours. Amy is now experiencing knee, hip, and lower back pain after working.
You have been asked to assemble a team to address the ergonomics issues Amy is facing and to explain a possible solution. Your assignment should meet the following criteria:
1. Identify and explain the different roles within the team (you may use bullets for this section).
2. Explain how the ergonomics team can work together to help Amy with her current workstation. Include a possible
suggestion to improve Amy’s workstation as part of your discussion.
3. Explain why it is important for the ergonomics team to implement a plan that considers potential discrimination or
disability issues for other employees.
This assignment should be at least two pages in length. Outside sources are not a requirement for this assignment. You are expected to complete this assignment based upon your reading, experience, and opinions.
1
Course Learning Outcomes for Unit
Upon completion of this unit, students should be able to:
5. Examine key management approaches for addressing workplace ergonomics issues.
5.1 Examine team-based strategies to address ergonomics-related hazards.
Reading Assignment
Chapter 6:
Elements of Ergonomics Programs
Chapter 7:
Biomechanics
Unit Lesson
In this unit, we get into the “meat and potatoes” of ergonomics. There is a great deal of very specific
information found in this unit and in the required reading. In Chapter 6, the authors discuss ergonomics
programs, which are broken down into specific categories. In this unit lesson, we will consider the role of the
ergonomics team within the larger context of the ergonomics program. Such programs involve a team effort,
which requires the commitment of top management and the involvement of a range of individuals including
safety and occupational health experts and frontline employees. Employees are actually experts at doing their
jobs and can offer important insight with respect to controlling ergonomic hazards. As your study of safety and
health continues, you will delve into many different facets of safety management systems, and ergonomics
will continue to be an important issue as you move forward.
Consider Amy who works as a cashier for a big-box store. Amy works long shifts standing up and often has to
lean forward to handle merchandise. She is often required to lift heavy boxes out of the oversized shopping
carts or flip them around to find the bar code in order to scan the product. Amy has an issue with her
workstation, and you are summoned to conduct an ergonomics-based hazard analysis of the workstation. Of
course, you are just one of the individuals who will be involved with performing the evaluation; there are
others with specialized expertise whom you can rely on to help you do a thorough job of identifying hazards
and recommending corrective actions.
As the safety professional, the first step will most likely include a cursory analysis of the workstation. Your
focus will likely be that of an occupational safety and health generalist, and you will note any safety and health
hazards that may be faced by Amy and other employees who do her job. Of course, your experience and
education should provide you with a good understanding of potential issues you might face and an
understanding of the specific functions of other experts whom you might want to call upon to include in the
evaluation process should the evaluation be complex enough to require a team approach. For instance, if
employees are sustaining cumulative trauma-related disorders, such as carpal tunnel syndrome or tendinitis,
it may be well-advised to include an occupational health professional such as an occupational health nurse. In
evaluations of complex operations, an occupational health physician may even be involved. The health
professional will have specific training that will allow him or her to look at the potential injuries or illnesses that
might be sustained as a result of working at the current workstation, and the training will also help him or her
to understand what injuries or illnesses might be created by implementation of the recommended corrective
actions. He or she will provide the team with the expertise to evaluate those injuries and may recommend
periodic medical evaluations to identify cumulative trauma disorders early in order to avoid exacerbation of
UNIT STUDY GUIDE
Elements of Ergonomics
and Biomechanics
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the disorder. It is more than likely this individual will be brought in from the outside of the company, as very
few companies have resident medical staff.
W ith that being said, if the workers at the company are part of a union, it will definitely be worth the time to
have the union representative involved in the workstation hazard analysis and to be available to the
employee. Unions play a very important role in representing workers at many facilities throughout the nation
with respect to workers’ compensation, benefits, and safety and health issues. Someone from management
will also be a part of the evaluation team because the company will surely want to be kept informed of what is
going on with the evaluation and how it may affect the company. If you are working for the company as a
safety manager, you may fulfill this role.
W hen the team starts making suggestions as to how to fix the potential hazards identified in evaluating Amy’s
workstation, the manager will be looking closely at those suggestions and the feasibility of the corrective
actions. Your suggestion might be to provide Amy with very good shoes to help prevent her from experiencing
foot pain and leg fatigue, and those shoes might cost $100; however, there are 2,000 other employees just
like Amy with similar job tasks, and you cannot get Amy shoes without making them available to everyone.
Your team’s fix might cost the company a quarter of a million dollars; therefore, management will want to be
involved in the process to make sure that any money spent is money well spent. A part of the evaluation
process will be to determine the cost savings of the fix versus the potential cost of going without the fix. Be
ready for that.
An industrial hygienist may also be a part of the team and will likely be involved with measurement and
analysis of lighting, noise, and indoor air quality issues. The industrial hygienist may also be involved with
taking biometric measurements. Chapter 7 discusses the biomechanics issue in greater depth. Take a look at
the ideas presented by the authors in the chapter. If you do not have a background in medicine or the health-
related professions, the chapter is quite good at describing the lever, fulcrum, and movement aspects of
biomechanics. As you will note in this reading, there is a great degree of variation between individuals who
make up the workforce. People come in a variety of shapes and sizes. This needs to be considered with
respect to identifying workplace hazards and recommending corrective actions. Raising a work bench to
accommodate a tall employee may cause problems if the next employee hired for the position is only 5 feet
tall!
Potentially, there will be many others involved in the process. It is very common, for instance, to include
frontline employees as they can provide special insight about the job that nobody else will necessarily be able
to identify. An individual from human resources (HR) could be involved as well to deal with issues related to
the Americans with Disabilities Act (ADA) or to ensure job descriptions reflect appropriate physical job
requirements such as the requirement to be able to lift a specific amount of weight. HR may also be involved
with making arrangements with healthcare facilities such as pre-screening of new hires.
One other person to consider for more complex workstation evaluations, of course, is the ergonomist.
Professional ergonomists are often involved in helping to assess workstations at large manufacturing and
food processing facilities. Some very large companies maintain a staff of full-time ergonomists. Also, it should
be noted that ergonomists do not work in isolation any more than you would while conducting or managing an
ergonomics evaluation. They almost always utilize a team approach that includes many of the professions we
have discussed in this reading and frequently includes frontline employees and industrial engineers as a part
of the overall evaluation process. It is clear that a given evaluation can range from being somewhat simp le,
such as in our present case with Amy, to very complex.
During the evaluation of the teams, there can be a great deal of information gathered to help assess the
relevant ergonomics-related hazards. The information gathered during the evaluation combined with the
company’s injury and illness data and other safety committee findings provides the team with useful data for
identifying ergonomic-related problems. This information is useful for understanding inherent hazards and for
recommending corrective actions for the workstation or job task being evaluated. Corrective actions could
involve anything from recommending footwear, adding floor mats, providing lift assistance devices, adjusting
conveyor heights, redesigning keyboards, allowing other workers to provide assistance for more difficult
tasks, improving lighting, implementing a job rotation, and even providing a stool that would help Amy to get
off of her feet from time to time. Note that this list of controls includes engineering controls, administrative
controls, and personal protective equipment (PPE).
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Of course, managing an ergonomics management team is only one part of the overall management effort, as
you will be able to discern from your readings. Overall, the management program should cont ain much more.
Many standard setting organizations, for instance, recommend high -level management commitment and
involvement of employees in safety -related programs (Pardy & Andrews, 2010). As mentioned above, the
evaluation phase is a good place to involve employees, and employee involvement is very important for
ensuring proper implementation of any management program (Amah & Ahiauzu, 2013). In addition to
management commitment and employee involvement, other important aspects of an ergonomics program
include implementation of controls identified as a result of workplace evaluation and analysis and a periodic
program evaluation to ensure continuous improvement (Pardy & Andrews, 2010). Such a management
approach is also encouraged in a number of industry-specific recommendations from the Occupational Safety
and Health Administration (OSHA) for the control of ergonomics-related hazards (OSHA, n.d.). W e will revisit
this management approach in a later unit.
It should be clear that the main takeaway from this lesson is that ergonomics evaluations frequently require a
multi-disciplinary team approach and serve an important role in the overall ergonomics management program .
This is partly because, unlike a situation where person cuts his or her finger on a metal flange sticking out of a
freshly cut piece of metal, ergonomics hazards are not always obvious. Likewise, when evaluating and
designing a workstation, an opportunity presents itself to make the job tasks as efficient as possible in the
interest of productivity. Employees who are injured or sore as a result of their job tasks are not likely to be
efficient as workers who have the opportunity to operate in a n ergonomically designed workstation.
Individuals who have a wide range of expertise in evaluating workstations and overseeing the implementation
of proper controls helps to ensure the safety and health of workers and optimizes productivity and quality
work.
References
Amah, E., & Ahiauzu, A. (2013). Employee involvement and organizational effective ness. The Journal of
Management Development, 32(7), 661-674.
Occupational Safety & Health Administration. (n.d.). Prevention of musculoskeletal disorders in the workplac e.
Retrieved from https://www.osha.gov/SLTC/ergonomics/index.html
Pardy, W ., & Andrews, T. (2010). Integrated management systems: Leading strategies and solutions.
Plymouth, United Kingdom: Government Institutes.
CHAPTER 6
ELEMENTS OF ERGONOMICS PROGRAMS
LEARNING OBJECTIVE
At the end of this chapter, students will define the elements of a good ergonomic program and apply the principles and guidelines in designing a good ergonomics program.
INTRODUCTION
The material at the beginning of this chapter follows the National Institute of Occupational Safety and Health (NIOSH) Suggested Elements of Ergonomics Programs (NIOSH, 1981).
Work-related musculoskeletal disorders (disorders of the muscles, nerves, tendons, ligaments, joints, or spinal discs) have increased dramatically in the past decade. These disorders are not typically the result of an acute event but reflect more gradual development, and the severity can range from mild to chronic and debilitating.
Ergonomics is defined as the science of fitting workplace conditions and job demands to the capabilities and limitations of the working population. Effective ergonomics promotes productivity, reduces injury risks, and increases worker comfort and satisfaction.
It is important to recognize and identify MSD problems. Some of the identifiers could be as follows:
·
Injury records review (OSHA logs or workers compensation claims)
· Comparison to industry averages
· Worker visits to clinic
· Jobs with repetitive, forceful exertions in awkward postures, frequent or heavy lifting, or vibrating equipment.
After identifying the problems, it is time to set the stage for action and integrate ergonomics into the company safety and health program. It is important to employ management commitment right from the beginning. A commitment of adequate resources including training the workforce, bringing in outside experts, and implementing improvements are vital to a successful program. Other vital aspects of a successful program are as follows:
· Treat ergonomics efforts as furthering the company’s goals.
· Expect full cooperation of the total workforce.
· Assign lead roles to designated persons.
· Give ergonomics efforts priority with other cost reduction, productivity, or quality efforts.
· Set goals to address specific operations and prioritize the riskiest jobs.
· Release time or other compensatory arrangements for employees expected to handle assigned tasks for ergonomics efforts.
· Provide information to all involved, including injury data and productivity data.
Worker Involvement Benefits
There are great benefits for the worker involvement that cover areas such as enhancing the worker motivation and job satisfaction; a greater knowledge of the work, organization, and workers are frequently the best source of ideas to fix the problem jobs. Involving the workers enables them to feel ownership in the program.
So who should participate? A list of individuals from various organizations within the companies may include the following:
· Safety and hygiene personnel
· Healthcare providers
· Human resources personnel
· Engineering personnel
· Maintenance personnel
· Ergonomists or ergonomics specialists
· Worker and management representatives.
Another approach may be to form committees or teams such as a joint labor-management committee approach or a work group approach (team approach). The individual input approach provides employees with a communication facility and can respond to input received.
ERGONOMICS AWARENESS TRAINING
It is very important to provide training in ergonomics awareness, job analyses and control measures, and some problem solving. The overall objectives that could be included in the ergonomics awareness training should be as follows:
· Recognize risk factors for MSDs and understand methods for controlling them.
· Identify signs and symptoms of MSDs and be familiar with company healthcare procedures.
· Know the process the employer is using to address and control risk factors.
· Know the procedure for reporting risk factors.
The overall objectives that could be included in the job analyses and control measures training should be as follows:
· Demonstrate job analysis for identifying risk factors for MSDs.
· Select ways to implement and evaluate control measures.
The overall objectives that could be included in the problem solving training should do the following:
· Identify departments, areas, and jobs with risk factors through records, walk-through observations, and surveys.
· Identify tools and techniques for conducting job analyses.
· Develop skills in team building and problem solving.
· Recommend ways to control hazards.
So how do you know if the program is needed? How do you know if the employees are experiencing problems? Some of the key indicators of MSDs are found in the health and medical department, where the employee reports of physical stress are housed. Other indicators may be to review the OSHA logs and other existing records as well as calculating rates for comparisons such as the following:
· Plant medical records
· Insurance claims records
· Absentee records
· Job transfer applications.
Surveys are a great way to target symptoms where the respondents are asked to rate their level of discomfort for different areas of the body, type, onset, and duration of the symptoms reported. Periodic medical examinations and employee interviews are also great indicators of MSDs. When identifying the risk factors in a job, there are several specific factors to look for:
· Awkward postures (extremes of joint movement)
· Twisting or bending while lifting or carrying
· Wrist deviations
· Overhead work (arms raised)
· Extended reaching, etc.
· Forceful exertions (including lifting, pushing, and pulling)
· Forces increase with the following:
· Weight or bulkiness of loads
· Speed of movements
· Use of awkward postures
· Presence of vibration, etc.
· Repetitive motions
· Frequent and similar motions every few seconds
· Increased risk when repeated forceful exertions in awkward postures
· Duration of exposure
· Amount of time a person is exposed to risk factors
· The longer the period of continuous work, the longer the required recovery or rest time
· Contact stresses
· Physical contact of body areas with hard or sharp objects
· Desk edges, tool handles, and so on
· Can inhibit nerve function and blood flow
· Vibration
· Localized exposure to vibrating object, such as a power hand tools
· Whole-body exposure to vibration when standing or sitting on vibrating equipment.
Other factors to be aware of are the conditions the workers are placed within such as the following:
· Cold
temperatures
· Insufficient pauses or rest breaks for recovery
· Machine paced work
· Unfamiliar or unaccustomed work.
Screening the various tasks/jobs for risk factors could be performed through walk-through observational surveys to determine the obvious risk factors. It is fairly easy to see if the worker is experiencing pain or discomfort while performing their tasks.
Other screening methods involve interviews with workers and supervisors and the use of checklists for scoring job features against a list of risk factors.
Job Analysis – Steps
When trying to analyze the job/task, one should first break the job into various elements or actions the job requires. Next, measure or quantify the risk factors and identify conditions contributing to risk factors. These should all be performed by individuals with considerable experience and training. The following is a list of the steps:
· Complete description of the job is obtained.
· Employees are interviewed.
· Job is divided into discrete tasks.
· Each task is then studied to determine specific risk factors.
· Risk factors may be further evaluated.
Job Analysis – Tasks
When looking at the tasks the workers need to perform in order to do their work, one could describe the tasks in terms of the following:
· Tools, equipment, and materials used to perform the job
· Workstation layout and physical environment
· Task demands and organizational climate.
Job Analysis – Detailed Data Collections
There are various sets of data that need to be collected to fully analyze the problems/issues within a company. The first one is collecting the data when observing the workers performing their tasks. The following illustrates the breakdown of the data collection information:
· Observe workers performing tasks to furnish time activity analysis
· Job/task cycle data
· Use videotape
· Still photos of postures, workstation layouts, tools, and so on
· Workstation measurements
· Work surface heights, reach distances, and so on.
· Measure tool handle sizes, weighing tools and parts, measure parts.
· Determine characteristics of work surfaces, such as slip resistance, hardness, and edges.
· Measure exposures to cold, heat, whole-body vibration, and so on.
· Biomechanical calculations (muscle forces required to complete task or pressure on spinal discs based on load lifted, for example, NIOSH lifting guide)
· Special questionnaires, interviews, and subjective rating procedures.
After analyzing the data, the next step would be to develop controls to help reduce the problems/issues. The three types of controls are as follows:
· Engineering controls: Reduce or eliminate potentially hazardous conditions
· Administrative controls: Changes in work practices and management policies
· Personal equipment.
Engineering Controls
When we look at the engineering controls of actually designing the job, we should look at
(1)
workstation layout,
(2)
selection and use of the tools, and
(3)
work methods. Some useful strategies for job design are as follows:
· Change the way materials, parts, and products can be transported (e.g., use mechanical assist devices rather than manual handling).
· Change the process or product to reduce risk factors (e.g., maintain the fit of plastic molds to reduce the need for manual removal of flashing).
· Modify containers and parts presentation (e.g., height-adjustable material bins).
· Change workstation layout (e.g., use height-adjustable workbenches).
· Change the way parts, tools, and materials are to be manipulated (e.g., use fixtures to hold work pieces).
· Change tool designs (e.g., pistol handle grips for knives to reduce wrist deviations).
· Change assembly access and sequence (e.g., remove physical and visual obstructions).
Administrative Controls
· Reduce shift length or curtail overtime.
· Rotate workers through several jobs with different physical demands.
· Schedule more breaks for rest and recovery.
· Broaden or vary job content.
· Adjust the work pace.
· Train workers to recognize risk factors for MSDs.
· Instruct workers in work practices that can ease task demands.
Personal Equipment
Is the personal equipment effective for the individual to perform their job? Hard-hats, safety shoes, safety goggles, and so on are barriers against hazards while wrist supports, back belts, and vibration attenuation gloves are not barriers against risk factors for MSDs. There has not been enough evidence presented to verify the effectiveness for these types of personal equipment.
Controls
The following is just a small sample of gathering ideas for implementing controls within the workplace.
· Trade associations that may have information about good control practices
· Insurance companies that offer loss control services
· Consultants and vendors who deal in ergonomic specialty services and products
· Visits to other worksites known to have dealt with similar situations.
The next step is to implement the controls within the workplace. Again, there are many ways to implement the different controls and the list provided below is just a sampling.
· Trials or tests of selected solutions.
· Making modifications or revisions.
· Full-scale implementation.
· Follow up to evaluate control effectiveness.
· Designate the personnel responsible.
· Create a timetable.
· Consider the logistics necessary for implementation.
When they have implemented the controls, it is important to evaluate their effectiveness. Some of the best ways to do this is to:
· Use risk factor checklist or other job evaluation methods.
· Repeat the symptoms survey and compare with prior results (often in conjunction with checklist or other job analysis method).
· Evaluation should occur 1–2 weeks after implementation (short-term evaluation).
· Long-term evaluations
· Reduction in incidence rate of MSDs
· Reduction in severity rate of MSDs
· Increase in productivity or quality of products or services
· Reduction in job turnover or absenteeism.
Healthcare Management – Employer/Employee/Healthcare Management Responsibilities
Responsibilities the employer should own are as follows:
· Provide education and training regarding recognition of symptoms and signs of MSDs.
· Encourage early reporting of symptoms and prompt evaluation by care provider.
· Give care provider opportunities to become familiar with jobs and tasks.
· Modify jobs/tasks or accommodate limitations.
· Ensure privacy of medical information.
· Follow workplace safety and health rules.
· Follow work practice procedures related to their jobs.
· Report early any signs or symptoms of MSDs.
The employee responsibilities are as follows:
· Follow workplace safety and health rules.
· Follow work practice procedures related to their jobs.
· Report early any signs or symptoms of MSDs.
The healthcare management or care provider responsibilities are as follows:
· Acquire experience and training in evaluation and treatment of MSDs.
· Seek information and review materials regarding employee job activities.
· Ensure employee privacy and confidentiality.
· Evaluate symptomatic employees.
· Evaluate symptomatic employees, including…
· Medical histories and symptoms.
· Descriptions of work activities.
· Physical examinations.
· Initial assessments or diagnoses.
· Consider opinions as to whether occupational risk factors caused, contributed to, or exacerbated conditions.
· Follow-up examinations to document improvements.
· Become familiar with employee’s job or tasks.
· Do periodic walk-throughs of the plant.
· Review job analysis reports or job descriptions.
· Review photographs or videotapes of jobs or tasks.
The best way to reduce issues and problems before they become serious is by early reporting. The employers should encourage early reporting and they should avoid establishing policies that discourage the reporting of symptoms. When the employee reports symptoms, the employer should provide prompt access to an evaluation by the company healthcare provider.
When the employee reports to the care providers, they should determine the worker’s physical capabilities and work restrictions and recommend the employer assign the worker to tasks that are consistent with any restrictions. The employer could assign light-duty or temporary job transfers for the individual. Do not completely remove the worker from work unless recommended from the healthcare provider.
Proactive Ergonomics
It is always better to be proactive versus reactive. A good proactive ergonomics program would do the following:
· Emphasize ergonomics at the design stage of work processes.
· Design operations that ensure proper selection and use of tools, job methods, workstation layouts, and materials.
· Build a more prevention-oriented approach using knowledge gained from the ongoing ergonomics process.
· Design strategies should emphasize fitting job demands to the capabilities and limitations of workers.
· Design strategies should target causes of MSDs – engineering approaches are preferred over administrative approaches.
The next portion of this chapter addresses the return on investing in an ergonomics program.
ERGONOMIC RETURN ON INVESTMENT METHODS
1.
Review the costs, both direct and indirect, typically associated with ergonomic injuries/illnesses.
2. Review techniques for quantifying return on investment to justify ergonomic interventions.
3. Share interventions successfully implement at worksites.
The objectives are to learn the costs associated with ergonomic injuries and learn techniques for quantifying return on investment to justify ergonomic interventions. Ergonomics is more than the right thing to do – it pays off. They will need to be able to make a good defensive argument when asking for funding for ergonomic interventions or an ergonomics program. In this module, we are going to give the numbers one need to justify their request. We will discuss success stories and show how to calculate return on investment. This is called throwing beans at the bean counter. Everyone is fighting for a share of the same budget and they will need to arm yourself with good data and a well thought-out argument for why they deserve part of the pie.
Direct costs are those costs that you can directly measure, whereas the indirect costs often go unnoticed and uncalculated. The iceberg theory is that most of the problem is under water and hard to detect but that’s the part that can sink ship.
The Iceberg Theory
What sinks the ship? (see
Figure 6.1
)
Indirect costs:
1. Loss of good will lower morale
2. Inefficiency costs of restricted work
3. Hiring and training replacement
4. Overtime to other employees because of injury
5. Administrative costs
6. Costs arising from violation or injury investigation/follow-up.
Figure 6.1
The rest of the iceberg what sinks the ship? (Original artwork by Lee Ostrom)
Indirect costs include restricted or light duty, hiring and training costs, administrative costs, and so on.
When one have a disability claim, it takes time from everyone whose desk it crosses – from the administrative assistant to the company executive officer. There are also costs associated with advertising a new job, filling the new job (HR costs), and training a new employee (trainer costs) as well as lost productivity as the new employee becomes familiar with the job. An injury hurts the morale of everyone involved from co-workers to safety specialists to family members – because cumulative trauma injuries are avoidable. Injuries are a negative experience for everyone involved. Employees on long-term disability cost the company money every year, and they do not contribute to the productivity – therefore, it is money spent every year with no gains.
Figure 6.2
illustrates the indirect costs in the iceberg theory.
Figure 6.2
The rest of the iceberg (indirect costs) sinks the ship (original artwork by Lee Ostrom)
For every $1 expended on Direct Costs, an additional $4 is expended on Indirect Costs. The following is taken from the Liberty Mutual Safety Index 1998 (Liberty Mutual Insurance Company).
Value of Direct Cost Saving per Musculoskeletal Disorder Averted
Value of lost production |
$14,763 |
Medical costs |
$3,080 |
Insurance administrative costs |
$1,872 |
Indirect costs to employers |
$2,832 |
OSHA estimates a 100% Return on Investment for preventive ergonomics over a 20-month payback period for most solutions.
Adapted from the OSHA Preliminary Economic Analysis and Initial Regulatory Flexibility Analysis for the Proposed Ergonomics Program Standard (OSHA, n.d.).
OSHA estimates that the total savings per prevented MSD is $22.5K.
One can calculate the average injury costs for your activity or use BLS data.
Potential injury is when there are no recorded injuries but potential still exists. One use this data to cost justify an intervention. For instance a $600 lift cart has the potential to prevent one $20K back strain.
These BLS numbers are from a report (Bureau of Labor Statistics, 2011)
Back strains |
$20,618 |
Other strains |
$14,600 |
CTS |
$9,300 |
Bureau of Labor Statistics (BLS) Cost Factors
First-aid injury |
$169 ea |
Lost workday injury |
$8,413 ea |
Lost workday back injury |
$100,000 ea |
A potential injury aversion to a back injury could be one where you provide equipment to facilitate lifting heavy or awkward objects.
Figure 6.3
illustrates a method to help reduce the load on the worker.
Figure 6.3
Solution: Carrying fixture designed by an employee and fabricated on-site
One adverted back injury
ROI method – Collect data, analyze, and relay information to the highest levels. When reporting the information, be specific and show the numbers.
Managers weighing decisions expect specifics:
1. Chargeback totals (5–10 years show cumulative costs)
2. Most frequently occurring injury type (WMSDs)
3. Most costly injury type (medical/compensation/productivity)
4. Average cost per injury type per year
5. Most efficient interventions
· Proof that practical, low-cost intervention is successful
· Cost per unit of ergonomic improvement = cost of intervention/number of workers helped.
One cannot predict specific injuries, but they can show increases in productivity, reduction in overall injury rates or severity, and costs. Do you know what you are spending on ergonomics? Go back 5–10 years in company records to find which injuries are ergonomic-related injuries.
WMSDs are usually the most costly injury type.
The most efficient solutions are usually low cost and can be used to address low hanging fruit. Inexpensive solutions, such as knee pads, are good protective equipment. Track expenditures in terms of cost per unit of ergonomic improvement = cost of intervention/# people helped. Some suggestions for low-cost solutions may be platforms and gloves.
Conduct your own mini study and give rivet gloves to riveters and compare injury rates to show improvement, $ spent, and people served versus injury rates. Budgets for safety glasses, respirators and steel toed shoes are not questioned, why not the leading cause of injuries? We know that the other preventative programs work, but no one ever asks how many injuries were prevented.
Figure 6.4
illustrates a hazard at a facility dealing with the laundry.
Figure 6.4
Throwing laundry over three flights of stairs
ROI Method – Intervention versus Injury Costs – Example Project
Hazards: Throwing dirty linens and trash over the side of the building, and carrying supplies and furniture up three decks.
In this example, we will use injury rates to justify an ergonomic fix. This example is from a transitional housing facility, which is three floors tall with no elevator.
A bag of linen, particularly wet towels, can weigh between 40 and 50 lb. Reaching into a cart to lift heavy bags of linen places the employee at risk of developing WMSDs of the back and shoulders. Linen is carried downstairs, pulled downstairs in a cart, or thrown over the balcony. When linen is thrown over the balcony, it has to be lifted over a 43 in. high railing and tossed past a 53 in. deep ledge, as shown in
Figure 6.4
. Throwing a heavy load over shoulder height for a distance places the employee at risk of injury to the upper extremities and back. Objects falling from overhead place people and property below at risk of damage or injury. Pushing or pulling a cart on stairs is dangerous for the employees and guests in the stairwell. Carts in the stairwell can inhibit emergency egress. There are currently 30 employees in transitional housing with a maximum of 34 employees during the summer due to an increase of persons staying in the facility over the summer.
ROI Method
1. Intervention versus injury costs
2. Ergonomic Intervention:
3. Cost Justification:
1. Injury data FY97–FY01
2. 14 recorded back injuries
3. Average cost of a Navy back injury $15,590
4.
5. Intervention cost/Average yearly back claim cost
6. 60,500 ÷ 43,652 = 1.38
7. 1.38 = 1 year 138 day payback period
The solution is a 3-story outdoor lift as shown in
Figure 6.5
. The cost is about 60K. This may seem like a lot, but if you look at the injury data from 1997 to 2001 in this facility, you will see 14 recorded back injuries.
1. ROI – 10-year cost savings
2. ROI method – Lifetime WMSD costs
Figure 6.5
Lift (Original artwork by Lee Ostrom)
What happens when work practices are not altered after an injury?
The following are examples of injuries sustained at a facility (Six Sigma Costs and Savings, n.d.).
Example 1
In 1978, a supervisor suffered a back injury while helping move sheet metal. Metal sheets were stacked and braced. There was no lost time except the day of the injury, and just $1000 in medical costs. A recurrent injury in 1992 cost $18K. This injury stayed on the books for many years and totaled over half a million dollars. The employee is still bent over and miserable and in pain. A 1K injury did not warrant a fix at the time, but a simple fix could have saved 500K+.
Example 2
Another employee was injured doing the same thing in 1996. At that time an ergonomics program was in place, and a single incident triggered an evaluation of the job.
There is now a metal clamp to hold the sheets and a roller table to move them. Sheets of metal are now stored in wheeled metal storage that pull out like books. Once the sheets are pulled out, the hoist can be brought over and clamped down. The total cost of this fix was $21K.
Figure 6.6
illustrates the metal storage and roller feed table system put into place within the facility.
1. Freestanding crane with magnetic clamp $12.2K
2. Roller feed table $1K
3. Metal sheet storage $8K
Figure 6.6
Example of the sheet metal storage and roller feed table
ROI Methods – Small Investment/Grand Payoff Ergo Joe Stretch n’ Flex Program at Puget Sound Naval Facility 1996
As part of the program, 6000 posters were displayed throughout the facility that reminded workers to stretch. Awareness training and Ergo Mentor and Ergonomic Orientation Training were conducted. The Ergo mentor training reminds work groups to stretch and educates through better working techniques (body mechanics). The data showed a 22% reduction in back injuries with a 90% voluntary participation. The program requires all employees to gather for 10 min at the beginning of each shift where stretching will be conducted, but the employees are not required to stretch, just be present.
Figure 6.7
is an example of a lateral stretch exercise.
Figure 6.7
Lateral stretch exercise
The next portion of this chapter will look at the benefits of Lean Engineering. A good ergonomics program allows the worker to function at their highest level of productivity, quality, and efficiency. Looking at Lean Engineering allows the process to function at its highest level of quality and efficiency as well.
· Both need a culture to be effective.
· Both are focused on the voice of the customer.
· Both strive to reduce waste.
ERGONOMICS PARALLELS LEAN 6 SIGMA
1. OSH/ergonomist are important elements in the cross-functional/cross-departmental team.
1. Vital in the improve/recommend phase.
2. Injury/illness metrics can be included in the cross-functional business metrics to measure progress.
2. Origins in industrial engineering.
1. LEAN concerned with manufacturing efficiency.
2. Ergonomics concerned with human efficiency.
3. LEAN 6 sigma strives to increase process performance and reduce output variation by removing waste.
3. Ergonomics strives to reduce the risk of injury and illness by matching the task … to the workers’ capabilities to maximize human performance (i.e., reduces wasteful human effort).
4. Ergonomics is most important at the level of work cell design and workstation design. By their very nature, well-designed cells relieve many of the risk factors associated with traditional workstations and functional layouts. For example, work cells often rotate workers through an entire process on each cycle. This reduces repetition and static postures. Workstations also have a direct influence on musculoskeletal disorders.
5. Both need a culture to be effective and sustainable; both are engineering-based disciplines.
6. Both strive to reduce waste in a sense.
7. Benefits of both methodologies
1. Reduced direct and indirect costs
2. Increased productivity.
3. Maximize performance.
4. Reduce waste.
5. Increase customer satisfaction.
6. Ergonomics efforts also increase retention and employee morale.
8. The mismatch between tasks … and employees capabilities may be key variables that introduce or maintain wasteful processes, reduce customer satisfaction, and affects process variation.
9. Poor quality or slow production can be linked to ergonomics.
The last portion of this chapter is an example of an occupational ergonomics safety program that could be developed using a regulatory standard.
MODEL SAFETY PROGRAM
1. DATE: _____________
2. SUBJECT: Occupational Ergonomics
3. REGULATORY STANDARD: OSHA – 29 CFR 1910.XXX (To Be Determined)
4. RESPONSIBILITY: The company
_______________
____
_____ is _________________. He/she is solely responsible for all facets of this program and has full authority to make necessary decisions to ensure success of the program. The ________________ is the sole person authorized to amend these instructions and is authorized to halt any operation of the company where there is danger of serious personal injury.
Contents of the (YOUR COMPANY) Occupational
Ergonomics Program
1. Written program
2. General requirements
3. Health surveillance
4. Ergonomic Assessment Committee
5. Program review and evaluation
6. Worksite analysis
7. Job hazard analysis
8. Hazard prevention and control
9. Periodic ergonomic surveys
10. Work practice controls
11. Administrative controls
12. Medical management
13. Training and education
14. Definitions.
(YOUR COMPANY) Occupational Ergonomics Program
1. 1. Written program. (YOUR COMPANY) will review and evaluate this standard practice instruction on an annual basis, or when changes occur that prompt revision of this document, or when facility operational changes occur that require a revision of this document. Effective implementation requires a written program for job safety, health, and ergonomics that is endorsed and advocated by the highest level of management within this company and that outlines its goals and plans. This written program is designed to establish clear goals and objectives. It encompasses the total workplace, regardless of the number of workers employed or the number of work shifts and will be communicated to all personnel at every level.
2. 2. General requirements. The goal of this program is to engineer problems out of the workplace wherever possible. Understanding that poor ergonomics in the workplace can result in cumulative trauma disorders (CTDs), and a host of other occupational injuries and conditions, (YOUR COMPANY) will establish ergonomic controls and operational procedures using this document as guidance.
3. 3. Health surveillance.
1. 3.1 Employee baseline. Prior to assignment, all new and transferred workers who are to be assigned to positions involving exposure of a particular body part to ergonomic stress will receive baseline health surveillance. The purpose of this baseline health surveillance is to establish a base against which changes in health status can be evaluated, not to preclude people from performing work.
3.1.1 Employee notification. Employees will be notified when they are placed in job descriptions where it is known or suspected that ergonomic hazards exist. These positions will be identified through the worksite analysis program discussed in Section 6 of this document and from the list of known high-risk jobs compiled by the company’s healthcare provider.
NOTE: Due to variations in personal health at any given time, the use of medical screening tests or examinations have not been validated as predictive procedures for determining the risk of a particular worker developing a CTD.
2. 3.2 Baseline health surveillance. The baseline health surveillance will include the following:
1. 3.2.1 A medical and occupational history.
2. 3.2.2 A physical examination will be performed by __________________ who is knowledgeable of the hazards associated with ergonomic stressors in general, and with the specific tasks to which the employee will be assigned. The examination will include the musculoskeletal and nervous systems as they relate to ergonomic stressors, palpation, range of motion (active, passive, and resisted), and other pertinent maneuvers of the upper extremities and back. Unless mitigating circumstances exist, laboratory tests, X-rays, and other diagnostic procedures will not be included as routine parts of the baseline assessment.
3. 3.3 Conditioning period follow-up. Supervisors will ensure that new and transferred employees will be given the opportunity to perform anticipated normally assigned tasks during a 4–6 week break-in period to condition their muscle–tendon groups prior to working at full capacity. A follow-up assessment of these workers after the break-in period (or after 1 month, if the break-in period is longer than a month) will be conducted to determine the following:
1. 3.3.1 If conditioning of the muscle–tendon groups has been successful.
2. 3.3.2 Whether any reported changes in physical well-being such as soreness or stiffness is transient and consistent with normal adaptation to the job, or whether it indicates the onset of stressors associated with ergonomic hazards that cannot be changed.
3. 3.3.3 If problems are identified, determine what appropriate action is required to change salient factors within the assigned task or the assigned employee that might be possible to better match the work to the worker.
4. 3.4 Periodic Health Surveillance. Periodic health surveillance (every 2–3 years) will be conducted on all employees who are assigned to positions involving exposure of a particular body part to ergonomic stress. The content of this assessment will include the following:
1. 3.4.1 A detailed update of the employee’s medical and occupational history.
2. 3.4.2 A physical examination by __________________ who is knowledgeable of the hazards associated with ergonomic stressors. The examination will include a personal assessment by the employee of his/her continuing capability of performing assigned tasks, as well as examination of musculoskeletal and nervous systems as they relate to ergonomic stressors, palpation, range of motion (active, passive, and resisted), and other pertinent maneuvers of the upper extremities and back. Unless mitigating circumstances exist, laboratory tests, X-rays, and other diagnostic procedures will not be included as routine parts of the baseline assessment.
3. 3.4.3 A detailed update of the employee’s medical and occupational history. See 3.4.1 above – repetitive.
5. 3.5 Documentation. Data gathered on employees as a result of health surveillance will be documented and filed in individual employee medical records.
4. 4. Ergonomic Assessment Committee. In order for this to be an effective program, (YOUR COMPANY) will provide for and encourage employee involvement in decisions at all levels that affect worker safety and health, including the following:
1. 4.1 Employee complaints, suggestions, or concerns will be brought to the attention of management. Feedback without fear of reprisal will be provided to all employees at every level.
2. 4.2 The
___________________
________ will maintain statistical data concerning reporting of signs and symptoms of ergonomic stressors by employees so that they can be evaluated and, if warranted, treated. This data will also direct managers to causal factors that may be evaluated for alteration, re-engineering or elimination. This data will be provided to the safety and health committee.
3. 4.3 The safety and health committee will, as necessary, analyze statistical data concerning ergonomic stressors, and make recommendations to specifically trained individual monitors assigned to the affected area or to an Ergonomic Assessment Committee for corrective action.
4. 4.4 An Ergonomic Assessment Committee will be established and/or specifically trained individual monitors will be assigned to conduct reviews of specifically identified jobs and tasks to analyze ergonomic stressors and recommend solutions. The _____________________ who is trained and locally certified as knowledgeable of the hazards associated with ergonomic stressors, will head the committee and direct activities. The committee will be composed of the following personnel.
1. Ergonomic Assessment Committee
1. Chairman
____________________________
_
_
2. Vice Chairman
_____________________________
_
3. Safety Officer
4. Supervisory personnel
5. Union Committee personnel
6. Hourly “lead” personnel
7. Hourly “nonlead” personnel
8. Member(s)
· Trained in industrial ergonomic hazards (general)
· Trained in office and sedentary ergonomic hazards
· Trained in repetitive motion hazards
· Trained in force/lifting hazards
· Trained in posture hazards
· Trained in industrial engineering and process flow.
9. Representative from timekeeping and costs department(s)
10. Workforce Management Committee
11. Representative of medical management familiar with tasks performed and any injury or pain complaints by our employees.
5. 5. Program review and evaluation. Senior company officers will review the ergonomics program regularly (semiannual reviews are recommended by OSHA) to evaluate implementation of the program, its success in meeting its goals and objectives, and to monitor costs and accomplishments. The results of the review will be in the form of a written progress report and program update. The report will be shared with all responsible parties and communicated to employees with special recognition of program participants who have contributed significantly to the success of ______________________ (YOUR COMPANY) by their participation and cooperation. New or revised goals arising from the review (identifying jobs, processes, and departments) will be provided to all employees. Information on deficiencies identified will include actions initiated. Evaluation techniques will include the following:
1. 5.1 Analysis of
1. trends in injury/illness rates with particular attention to ergonomic injuries and recovery statistics
2. 5.2 Employee surveys
3. 5.3 Before and after surveys/evaluations of job/worksite changes
4. 5.4 Review of results of plant evaluations with recommended improvements
5. 5.5 Up-to-date records or logs of Ergonomic Projects for job improvements tried or implemented including any pertinent injury/illness data for each. Cost data will be included wherever appropriate, both on production lost due to ergonomic challenges and costs related to eliminating ergonomic hazards.
*Decision point: The following procedures should be adapted to each workplace.
2. 6. Worksite analysis. Worksite analyses identify existing ergonomic hazards as well as conditions and/or operations that pose ergonomic challenges and areas where hazards may develop. This also includes close scrutiny and tracking of injury and illness records to identify patterns of trauma or strains that may indicate the development of CTDs. The objectives of worksite analyses are to recognize, identify, and correct ergonomic challenges. The following guidance provides a starting point for finding and eliminating those tools, techniques, and conditions, which may be the source of ergonomic problems. In addition to analyzing current workplace conditions, planned changes should be reviewed for potential ergonomic hazards before they are implemented. Changes to existing and new facilities, processes, materials, and equipment can be considered to ensure that changes made to enhance production will also reduce or eliminate risk factors. Worksite analysis is divided into four main parts: (1) Gathering information from all available sources. (2) Conducting employee baseline screening surveys to help determine which tasks need closer analysis. (3) Performing ergonomic job hazard analyses of those work stations with identified or potential risk factors.
(4)
After implementing control measures, conducting periodic surveys and follow-up to evaluate effectiveness of ergonomic improvement including costs and injury prevention as well as productivity improvement. Worksite analyses will be performed following the below listed procedures.
1. 6.1 Information sources
1. 6.1.1 Records analysis and tracking. Existing medical, safety, and insurance records, including OSHA-300 logs, will be analyzed for evidence of injuries or disorders associated with ergonomic stressors. Healthcare providers will be asked to participate in this process to ensure confidentiality of patient records and to identify correlation between ergonomic hazards in a specific task and the injury or condition reported. The purpose will be to develop the information necessary to identify ergonomic hazards in the workplace.
2. 6.1.2 Incidence rates. Incidence rates for upper extremity disorders and/or back injuries should be calculated by counting the incidences of CTDs and reporting the incidences per 100 full-time workers per year per facility. In this calculation, the average employee works 2000 h/year. One hundred employees are reflected in the figure “200,000 work hours.” Therefore,
*The same method can be applied to departments, production lines, or job types within the facility by adjusting the number of hours actually worked by the employees within that subgroup or within that adjusted time period.
2. 6.2 Screening surveys. Detailed baseline screening surveys will be conducted to identify jobs that put our employees at risk.
6.2.1 Checklist. The survey will be performed with an ergonomic checklist. This checklist will include components such as posture, materials handling, and upper extremity factors. The checklist will be tailored to the specific needs and conditions of a particular task or series of tasks within the workplace.
*Decision point examples of an ergonomic checklist are provided in the publication Cumulative Trauma Disorders by Putz-Anderson, p. 52. In addition, other examples of checklists will be given in OSHA’s forthcoming Ergonomics Program Management Guidelines for General Industry. (A sample ergonomic checklist is attached for your review and clarification.)
2. 6.2.2 Ergonomic risk factors. Identification of potential ergonomic hazards will be based on risk factors such as conditions of a job/task/process such as extreme heat/cold, height, confined area, bulky or uneven weights, lack of solid grip points, poorly designed work station, or work methods that contribute to the risk of developing problems associated with ergonomic stressors. Not all of these risk factors will be present in every job containing ergonomic challenges, nor is the existence of one of these factors necessarily sufficient to cause a problem associated with CTD’s. Supervisors will ensure that known risk factors for specific employees, jobs or tasks are conveyed to the Ergonomic Assessment Committee for improvement or correction. Supervisors will use the following known risk factors to isolate and report suspected problem areas:
1. Personal risk factors
1. Gender
1. Age
1. Anthropometry
1. Work method
1. Attitude
1. Training
1. Sight
1. Hearing
1. Smell
1. Physical strength
1. Weight
1. Upper extremities risk factors
2. Repetitive and/or prolonged activities
2. Forceful exertions, usually with the hands
2. Pinch grips
2. Prolonged static postures
2. Awkward postures
5. Reaching above the shoulders
5. Reaching behind the back
5. Unusual twisting of wrists and other joints
2. Continued physical contact with work surfaces
2. Excessive vibration from power tools
2. Inappropriate or inadequate hand tools
1. Back disorder risk factors
3. Bad body mechanics such as
1. Continued bending over at the waist
1. Continued lifting from below the knuckles
1. Continued lifting above the shoulders
1. Twisting at the waist
1. Twisting at the waist, while lifting.
1. Lifting or moving objects of excessive weight
1. Lifting or moving objects of asymmetric size
1. Prolonged sitting, with poor posture.
1. Lack of adjustable
9. Chairs
9. Footrests
9. Body supports
9. Work surfaces at work stations
1. Poor grips on handles
1. Slippery footing
1. Frequency of movement
1. Duration and pace
1. Stability of load
1. Coupling of load
15. Type of grip
1. Reach distances
1. Work height
1. Environmental risk factors
4. Type of floor surface at work stations
4. Type of platforms
4. Work station temperature
3. Hot
1. Glove (reduces
1.
i.
·
·
·
· grip by up to 30%)
· Fatigue
· Sweat
· Personal protective equipment (PPE)
· Cold
· Glove (reduces grip by up to 30%)
· PPE
· Lighting
· Too bright
· Too dim
· Noise
· Distractions
· Associated fatigue
· Vibration
· Associated fatigue
· Resonation through body
· Resonation through tools
· Multiple risk factors. Jobs, operations, or work stations that have multiple risk factors have a higher probability of ergonomic risk. The combined effect of several risk factors is sometimes referred to as “multiple causation.”
2. 7. Job hazard analysis. This employer will identify through the use of information sources and screening surveys, jobs that place employees at risk. After a worksite analysis has been completed, a job hazard analysis for each job so identified will be conducted. Job hazard analyses will be routinely performed by qualified person(s) for jobs that put workers at risk. This analysis will help to verify lower risk factors at light duty or restricted activity work positions and to determine if risk factors for a work position have been reduced or eliminated to the extent feasible.
1. 7.1 The following personnel or job positions are qualified to perform job hazard analysis surveys for this company.
Personnel Qualified to Perform Job Hazard Analysis
Name |
Title |
||||||||||||||||||||||||||
(1) | _____________________________ | ____________________________ | |||||||||||||||||||||||||
(2) | |||||||||||||||||||||||||||
(3) | |||||||||||||||||||||||||||
(4) | |||||||||||||||||||||||||||
(5) |
|||||||||||||||||||||||||||
(6) |
2. 7.2 Work station analysis. Work station analysis will be conducted to identify risk factors present in each job or workstation.
2. 7.2.1 Upper extremities. For upper extremities, three measurements of repetitiveness will be reviewed; they are as follows:
1. 7.2.1.1 Total hand manipulations per cycle.
1. 7.2.1.2 Cycle time.
1. 7.2.1.3 Total manipulations or cycles per work shift.
2. 7.2.2 Force measurements. Force measurements will be noted as an estimated average effort, and a peak force. They will be recorded as “light,” “moderate,” and “heavy.”
2. 7.2.3 Tools. Tools will be checked for excessive vibration. (The NIOSH criteria document on hand/arm vibration should be consulted.)
2. 7.2.4 The tools, personal protective equipment, and dimensions and adjustability of the work station will be noted for each job hazard analysis.
2. 7.2.5 Postures. Hand, arm, and shoulder postures and movements will be assessed for levels of risk.
2. 7.2.6 Lifting hazards. Work stations having tasks requiring manual materials handling will have the maximum weight-lifting values calculated. (The NIOSH Work Practices Guide for Manual Lifting, 1981, should be used for basic calculations. Note that this guide does not address lifting that involves twisting or turning motions.)
2. 7.2.7 Videotape method. The use of videotape, where feasible, will be used as a method for analysis of the work process. Slow-motion videotape or equivalent visual records of workers performing their routine job tasks will used where practical to determine the demands of the task on the worker and how each worker actually performs each task. A task analysis log/form will be used to break down the job into components that can be individually analyzed.
1. 8. Hazard prevention and control: This company understands that engineering solutions, where feasible, are the preferred method of control for ergonomic hazards. The focus of ABC’s ergonomics program is to make the job fit the person, not to make the person fit the job. This is accomplished whenever possible by redesigning the work station, work methods, or tool(s) to reduce the demands of the job, including high force, repetitive motion, and awkward postures. This program will whenever possible research into currently available controls and technology. The following examples of engineering controls will be used as models for work station design and upgrade at (YOUR COMPANY).
1. 8.1 Work station design. Work stations when initially constructed or when redesigned will be adjustable in order to accommodate the person who actually works at a given work station; it is not adequate to design for the “average” or typical worker. Work stations should be easily adjustable and either designed or selected to fit a specific task, so that they are comfortable for the workers using them. The work space should be large enough to allow for the full range of required movements, especially where handheld tools are used. Examples include the following:
0. 8.1.1 Adjustable fixtures on work tables so that the position of the work can be easily manipulated.
0. 8.1.2 Work stations and delivery bins that can accommodate the heights and reach limitations of various-sized workers.
0. 8.1.3 Work platforms that move up and down for various operations.
0. 8.1.4 Mechanical or powered assists to eliminate the use of extreme force.
0. 8.1.5 Suspension of heavy tools.
0. 8.1.6 Use of diverging conveyors off of main lines so that certain activities can be performed at slower rates.
0. 8.1.7 Floor mats designed to reduce trauma to the legs and back.
1. 8.2 Design of work methods. Traditional work method analysis considers static postures and repetition rates. This will be supplemented by addressing the force levels and the hand and arm postures involved. The tasks will be altered where possible to reduce these and the other stresses. The results of such analyses will be shared with employee healthcare providers; for example, to assist in compiling lists of “light-duty” and “high-risk” jobs. Examples of methods for the reduction of extreme and awkward postures include the following:
1. 8.2.1 Enabling the worker to perform the task with two hands instead of one.
1. 8.2.2 Conforming to the NIOSH Work Practices Guide for Manual Lifting.
1. 8.3 Excessive force. Excessive force in any operation can result in both long-term problems for the worker and increased accident rates. Ways to reduce excessive force will be continually emphasized by first-line supervisors and employees. Examples of methods to reduce excessive force include the following:
2. 8.3.1 Use of automation devices.
2. 8.3.2 Use of mechanical devices to aid in removing scrap from work areas.
2. 8.3.3 Substitution of power tools where manual tools are now in use.
2. 8.3.4 Use of articulated arms and counter balances suspended by overhead racks to reduce the force needed to operate and control power tools.
1. 8.4 Repetitive motion. All efforts to reduce repetitive motion will be pursued. Examples of methods to reduce highly repetitive movements include the following:
3. 8.4.1 Increasing the number of workers performing a task.
3. 8.4.2 Lessening repetition by combining jobs with very short cycle times, thereby increasing cycle time (sometimes referred to as “job enlargement.”).
3. 8.4.3 Using automation where appropriate.
3. 8.4.4 Designing or altering jobs to allow self-pacing, when feasible.
3. 8.4.5 Designing or altering jobs to allow sufficient rest pauses.
1. 8.5 Tool design and handles. Supervisors will use ergonomic principles in the selection and or design of tools to minimize the risks of upper extremity CTDs and back injuries. In any tool design, a variety of sizes should be available. Examples of criteria for selecting tools include the following:
4. 8.5.1 Matching the type of tool to the task.
4. 8.5.2 Designing or selecting the tool handle so that extreme and awkward postures are minimized.
4. 8.5.3 Using tool handles with textured grips in preference to those with ridges and grooves.
4. 8.5.4 Designing tools to be used by either hand, or providing tools for left- and right-handed workers.
1. 8.5.5 Using
1.
1. tools with triggers that depress easily and are activated by two or more fingers.
2. 8.5.6 Using handles and grips that distribute the pressure over the fleshy part of the palm, so that the tool does not dig into the palm.
3. 8.5.7 Designing/selecting tools for minimum weight; counterbalancing tools heavier than 1 or 2 lb.
8.5.8 Selecting pneumatic and power tools that exhibit minimal vibration and maintaining them in accordance with manufacturer’s specifications, or with an adequate vibration monitoring program.
Note: Wrapping handles and grips with insulation material (other than wraps provided by the manufacturer for this purpose) is normally not recommended, as it may interfere with a proper grip and increases stress.
4. 8.5.9 Selecting tools that minimize chronic muscle contraction or steady force.
5. 8.5.10 Selecting tools that prevent extreme or awkward finger/hand/arm positions.
6. 8.5.11 Selecting tools that minimize repetitive forceful motions.
7. 8.5.12 Selecting tools that minimize tool vibration.
8. 8.5.13 Selecting tools that minimize excessive gripping, pinching, pressing with the hand and fingers.
2. 9. Periodic ergonomic surveys. Periodic surveys will be conducted to identify previously unnoticed risk factors or failures or deficiencies in work practice or engineering controls. Periodic surveys will be conducted on a(n) ____________________ basis. The periodic review process will include the following:
1. 9.1 Feedback and follow-up. The company hazard notification system (safety program) will be used to provide employees with a system to notify management about conditions that appear to be potential ergonomic hazards. This process will allow this company to utilize their insight and experience to determine work practice and engineering controls.
1. 9.1.1 Ergonomic questionnaires will be used to provide feedback on jobs, workstations, and tasks previously modified to incorporate ergonomic principles and upgrades.
2. 9.1.2 Reports of ergonomic hazards or signs and symptoms of potential problem areas will be investigated by ergonomic screening surveys and appropriate ergonomic hazard analyses in order to identify risk factors and controls.
3. 9.1.3 Trend analysis. Trends of injuries and illnesses related to actual or potential CTDs will be calculated, using multiple years of data where possible. Trends will be calculated for several departments, job titles, or work stations. These trends will also be used to determine which work positions are most hazardous and will be analyzed by the ergonomics assessment committee, and other responsible company personnel.
4. 9.1.4 By using standardized job descriptions, incidence rates may be calculated for work positions in successive years to identify trends. Therefore, (YOUR COMPANY) where possible will correlate previous and current job position titles. Using trend information can help to determine the priority of screening surveys and/or ergonomic hazard analyses.
5. 9.1.5 Medical, safety, and insurance records, including the OSHA-200 log and information compiled through the medical management program will be used to provide evidence (or lack of) of ergonomic stressors. Company healthcare providers will be used to compile data from medical records to ensure confidentiality. This process should involve the identification and analysis of any apparent trends relating to particular departments, job titles, operations, work stations, or individual tasks.
3. 10. Work practice controls. An effective program for hazard prevention and control also includes procedures for safe and proper work that are understood and followed by ABC managers, supervisors, and workers. Key elements of a good work practice program for ergonomics include proper work techniques, employee conditioning, regular monitoring, feedback, maintenance, adjustments and modifications, and enforcement.
1. 10.1 Proper work techniques. Supervisor awareness and control of proper work techniques will improve safety. The following includes appropriate training and work practice controls for our employees:
1. 10.1.1 Proper work techniques, including work methods that improve posture and reduce stress and strain on extremities.
2. 10.1.2 Good tool care, including regular maintenance.
3. 10.1.3 Correct lifting techniques (proper body mechanics).
4. 10.1.4 Proper selection, use, and maintenance of all tools associated with the job.
5. 10.1.5 Correct installation and use of ergonomically designed work stations and fixtures.
2. 10.2 New employee conditioning period. Supervisors will ensure that new or transferred employees are allowed an appropriate conditioning period. New and returning employees will be gradually integrated into a full workload as appropriate for specific jobs and individuals. Employees will be assigned to an experienced trainer for job training and evaluation during the break-in period. Employees reassigned to new jobs should also have a break-in period. Important – Supervisors will closely monitor employees that fall into this category throughout their break-in period.
3. 10.3 Monitoring. Regular monitoring at all levels of operation helps to ensure that employees continue to use proper work practices. This monitoring will include a periodic review of the techniques in use and their effectiveness, including a determination of whether the procedures in use are those specified; if not, then it should be determined why changes have occurred and whether corrective action is necessary.
4. 10.4 Adjustments and modifications. Supervisors must continually be aware of changes in the dynamics of the workplace and to make appropriate operational changes. Such changes may include the following:
1. 10.4.1 Line speeds
2. 10.4.2 Staffing changes
3. 10.4.3 Type, size, weight, or temperature of the product handled
4. 10.4.4 Worker health and attitude changes.
5. 10.5 Personal protective equipment (PPE). PPE used by employees of this company will be selected with ergonomic principles, and stressors in mind. Appropriate PPE will be provided in a variety of sizes, will accommodate the physical requirements of workers and the job, and will not contribute to extreme postures and excessive forces. Supervisors will consider the following factors when selecting PPE for personnel under their control:
1. 10.5.1 Proper fit. For example, gloves that are too thick or that fit improperly can reduce blood circulation and sensory feedback, contribute to slippage, and require excessive or increased grip strength. The same is true when excessive layers of gloves are used (e.g., rubber over fabric, over metal mesh, over cotton). The gloves in use should facilitate the grasping of the tools needed for a particular job while protecting the worker from injury.
2. 10.5.2 Protection against extreme cold is necessary to minimize stress on joints.
3. 10.5.3 Protection against extreme heat is necessary to minimize slippage caused by perspiration. Also, to be considered, if slippage is occurring grip strength will be affected (reduced by up to 30%).
4. 10.5.4 Other types of PPE that may be selected for use should be reviewed before purchase to ensure that there is no increase of ergonomic stressors.
4. 11. Administrative controls. Company administrative controls will be used to reduce the duration, frequency, and severity of exposures to ergonomic stressors. Examples of administrative controls include the following:
1. 11.1 Reducing the total number of repetitions per employee by such means as decreasing production rates and limiting overtime work.
2. 11.2 Providing rest pauses to relieve fatigued muscle–tendon groups. The length of time needed depends on the task’s overall effort and total cycle time.
3. 11.3 Increasing the number of employees assigned to a task to alleviate severe conditions, especially in lifting heavy objects.
4. 11.4 Using job rotation, used with caution and as a preventive measure, not as a response to symptoms. The principle of job rotation is to alleviate physical fatigue and stress of a particular set of muscles and tendons by rotating employees among other jobs that use different muscle–tendon groups. If rotation is utilized, the job analyses must be reviewed to ensure that the same muscle–tendon groups are not used when they are rotated.
5. 11.5 Providing sufficient numbers of standby/relief personnel to compensate for foreseeable upset conditions on the line (e.g., loss of workers).
6. 11.6 Job enlargement. Having employees perform broader functions that reduce the stress on specific muscle groups while performing individual tasks.
1. *Decision point OSHA recommendation – where healthcare providers are not employed full time, the part-time employment of appropriately trained healthcare providers is recommended.
2. 12. Medical management. _______________________ will manage the program. Employees of each work shift should have access to healthcare providers or designated alternates in order to facilitate treatment, surveillance activities, and recording of information. The medical management program will as a minimum address the following issues:
1. 12.1 Injury and illness recordkeeping
2. 12.2 Early recognition and reporting
3. 12.3 Systematic evaluation and referral
4. 12.4 Conservative treatment
5. 12.5 Conservative return to work
6. 12.6 Systematic monitoring
7. 12.7 Adequate staffing and facilities
8. 12.8 Recordability criteria. Most conditions classified as CTDs will be recorded on the OSHA-200 form as an occupational illness under the “7f” column, which are “disorders associated with repeated trauma.” These are disorders caused, aggravated, or precipitated by repeated motion, vibration, or pressure. In order to be recordable, the following criteria must be met:
1. 12.8.1 The illnesses must be work related. This means that exposure at work either caused or contributed to the onset of symptoms or aggravated existing symptoms to the point that they meet OSHA recordability criteria. Simply stated, unless the illness was caused solely by a nonwork-related event or exposure off-premises, the case is presumed to be work related. Examples of work tasks or working conditions that are likely to elicit a work-related CTD are as follows:
1. 12.8.1.1 Repetitive and/or prolonged physical activities
2. 12.8.1.2 Forceful exertions, usually with the hands (including tools requiring pinching or gripping)
3. 12.8.1.3 Awkward postures of the upper body, including reaching above the shoulders or behind the back, and angulation of the wrists to perform tasks
4. 12.8.1.4 Localized contact areas between the work or work station and the worker’s body; that is, contact with surfaces or edges
5. 12.8.1.5 Excessive vibration from power tools
6. 12.8.1.6 Cold temperatures.
2. 12.8.2 A CTD must exist. There must be either physical findings or subjective symptoms and resulting action, namely:
1. 12.8.2.1 There must be at least one physical finding (e.g., positive Tinel’s, Phalen’s, or Finkelstein’s test; or swelling, redness, or deformity; or loss of motion).
2. 12.8.2.2 There must be at least one subjective symptom (e.g., pain, numbness, tingling, aching, stiffness, or burning), and at least one of the following. (1) Medical treatment including self-administered treatment when made available to employees by this employer. (2) Lost workdays (includes restricted work activity). (3) Transfer/rotation to another job.
Note: If the above criteria are met, then a CTD illness exists that must be recorded on the OSHA-300 form. EXAMPLE. A production line employee reports to the health unit with complaints of pain and numbness in the hand and wrist. The employee is given aspirin and, after a follow-up visit with no change in symptoms, is reassigned to a restricted-duty job. Even though there are no positive physical signs, the case is recordable because work activity was restricted.
9. 12.9 Occupational injuries. Injuries are caused by instantaneous events in the work environment. To keep recordkeeping determinations as simple and equitable as possible, back cases are classified as injuries, even though some back conditions may be triggered by an instantaneous event and others develop as a result of repeated trauma. Any occupational injury involving medical treatment, loss of consciousness, restriction of work or motion, or transfer to another job is to be recorded on the OSHA-300 form.
10. 12.10 Evaluation, treatment, and follow-up of CTD’s. If CTDs are recognized and treated appropriately early in their development, a more serious condition likely can be prevented; therefore, it is important to identify and treat these disorders as early as possible. The following systematic approach will be used to evaluate employees who report to the health unit.
1. 12.10.1 Screening assessment. Upon the employee’s presentation of symptoms, the healthcare provider’s screening assessment will include, obtaining a history from the employee to identify the location, duration and onset of pain/discomfort, swelling, tingling and/or numbness, and associated aggravating factors. A brief noninvasive screening examination for the evaluation of CTDs will consist of inspection, palpation, range of motion testing, and various applicable maneuvers. (See Barbara Silverstein, Evaluation of Upper Extremity and Low Back, Selected Bibliography.)
1. 12.10.1.1 Based on the severity of symptoms and physical signs, the _____________ or other healthcare provider will decide whether to initiate conservative treatment and/or to refer promptly to a physician for further evaluation.
2. 12.10.1.2 If mild symptoms and no physical signs are present, conservative treatment is recommended. Examples include the following:
· Applying heat or cold. Ice is used to treat overuse strains and muscle/tendon disorders for relief of pain and swelling, thus allowing more mobility. Ice decreases the inflammation associated with CTDs even if no overt signs of inflammation (redness, warmth, or swelling) are present. The use of ice may be inappropriate for Raynaud’s disease (vibration syndrome), rheumatoid arthritis, and diabetic conditions. Heat treatments should be used only for muscle strains where no physical signs of inflammation are present.
· Nonsteroidal anti-inflammatory agents. These agents may be helpful in reducing inflammation and pain. Examples of these types of agents include aspirin and ibuprofen.
· Special exercise. If active exercises are utilized for employees with CTDs, they should be administered under the supervision of the OHN or physical therapist. If these active exercises are performed improperly, they may aggravate the existing condition.
· Splints. A splint may be used to immobilize movement of the muscles, tendons, and nerves. Splints should not be used during working activities unless it has been determined by the OHN and ergonomist that no wrist deviation or bending is performed on the job. Splinting can result in a weakening of the muscle, loss of normal range of motion due to inactivity, or even greater stress on the area if activities are carried out while wearing the splint.
2. 12.10.2 Follow-up assessment after 2 days.
1. 12.10.2.1 If the condition has resolved, reinforce good work practices and encourage the employee to return to the health facility if there are problems.
2. 12.10.2.2 If the condition has improved but is not resolved, continue the above treatment for approximately 2 days and reevaluate.
3. 12.10.2.3 If the condition is unchanged or worse, check compliance with the prescribed treatment and perform a screening examination.
4. 12.10.2.4 If the screening examination is positive, or if the condition is worse, the employee will be referred to the company physician, and reassigned to a light or restricted-duty position. If the screening examination is negative for physical signs, but the condition is unchanged, conservative treatment will be continued.
5. 12.10.2.5 Job reassignments will be coordinated with the supervisor and must be chosen with knowledge of whether the new task will require the use of the injured tendons, or place pressure on the injured nerves. Inappropriate job reassignment can continue to injure the inflamed tendon or nerve, which can result in permanent symptoms or disability. The appropriate light-duty job can be selected from the low ergonomic risk jobs list maintained by the healthcare provider. These restricted or light-duty jobs are one of the most helpful treatments for CTDs. These jobs, if properly selected, allow the worker to perform while continuing to ensure recovery. Some CTDs require weeks (or months, in rare cases) of reduced activity to allow for complete recovery.
3. 12.10.3 Follow-up assessment after 6 days.
1. 12.10.3.1 After about 6 days, if the condition appears to have been resolved, supervisors will be notified, good work practices should be reinforced, and the employee should be encouraged to return to the health facility if problems resurface.
1. 12.10.3.2 If
1.
1.
1. the condition has improved but is not resolved, the above treatment will be continued for approximately 2 more days and reevaluated.
2. 12.10.3.3 If the condition is unchanged or worse, compliance with prescribed treatment should be checked and a screening examination performed. If the screening examination is positive, the employee will be referred to the company physician.
2. 12.10.4 Follow-up after 8 days.
1. 12.10.4.1 If, after about 8 days, the condition has resolved, good work practices will be reinforced and the employee will be encouraged to return to the health facility if problems resurface.
2. 12.10.4.2 If the condition has not resolved within approximately 8 days, the employee will be referred to the company physician automatically.
3. 12.10.5 Other considerations
1. 12.10.5.1 If an employee misses a scheduled reevaluation, the healthcare provider will contact the employee to assess the condition within approximately 5 days of the last presentation.
2. 12.10.5.2 The referring physicians or healthcare providers will be furnished with a written description of the ergonomic characteristics of the job of the employee who is being referred.
4. 12.10.6 Surgery. Recommendations for surgery will be referred for a second opinion. If surgery is performed, an appropriate amount of time off work is essential to allow healing to occur and prevent recurrence of symptoms. The number of days off work will depend on each worker’s individual response and will agree with the recommendations of the treating physician.
5. 12.10.7 Return to work. A physician evaluation of the employee after time away from work, to assess work capabilities, will be performed to ensure appropriate job placement. When an employee returns to work after time off, after an operation, or must rest an inflamed tendon, ligament, or nerve, there will be a reconditioning of the healing muscle–tendon groups. Supervisors and healthcare providers will give consideration to permanently reassigning the employee to an available job with the lowest risk of developing CTDs.
2. 12.11 Other considerations
1. 12.11.1 A case is considered to be complete once there is complete resolution of the signs and symptoms. After resolution of the problem, if the signs or symptoms recur, a new case is established and thus must be recorded on the OSHA 200 form as such. Furthermore, failure of the worker to return for care after 30 days indicates symptom resolution. Any visit to a healthcare provider for similar complaints after the 30-day interval implies reinjury or reexposure to a workplace hazard and would represent a new case.
2. 12.11.2 It is essential that required data, including job identification, be consistently, fully, and accurately recorded on the OSHA-200 form. “Job identification” will include the appropriate job title for “Occupation” and the appropriate organizational unit for “Department” on the OSHA-200.
3. 12.11.3 Periodic workplace walk-throughs. Healthcare providers will conduct periodic, systematic workplace walk-throughs on a monthly basis (OSHA recommended) to remain knowledgeable about operations and work practices, to identify potential light-duty jobs, and to maintain close contact with employees. Healthcare providers also should be involved in identifying risk factors for CTDs in the workplace as part of the ergonomic team. A record will be kept documenting the date of the walk-through, area(s) visited, risk factors recognized, and action initiated to correct identified problems. Follow-up will be initiated and documented to ensure corrective action is taken when indicated.
3. 12.12 Trend analysis
1. 12.12.1 Company healthcare providers should periodically (e.g., quarterly) review healthcare facility sign-in logs, OSHA-200 forms, and individual employee medical records to monitor trends for CTDs in our facilities. This ongoing analysis should be made in addition to a “symptoms survey” to monitor trends continuously and to substantiate the information obtained in the annual symptoms survey. The analysis should be done by department, job title, work area, and so on.
2. 12.12.2 The information gathered from the annual symptoms survey will help to identify areas or jobs where potential CTD problems exist. This information may be shared with anyone in the plant, since employees’ personal identifiers are not solicited. The analysis of medical records (e.g., sign-in logs and individual employee medical records) may reveal areas or jobs of concern, but it may also identify individual workers who require further follow-up. The information gathered while analyzing medical records will be of a confidential nature; thus, care must be exercised to protect the individual employee’s privacy.
3. 12.12.3 The information gained from the CTD trend analysis and symptoms survey will help determine the effectiveness of the various programs initiated to decrease ergonomic problems in our facilities.
4. 12.13 Symptoms survey. A symptoms survey will be developed to provide a standardized measure of the extent of symptoms of work-related disorders for each area of the plant, to determine which jobs are exhibiting problems and to measure progress of the ergonomic program.
1. 12.13.1 Design of survey. A survey of employees will be conducted to measure employee awareness of work-related disorders and to report the location, frequency, and duration of discomfort. Body diagrams will be used to facilitate the gathering of this information.
2. 12.13.2 Surveys normally will not include employees’ personal identifiers, this is to encourage employee participation in the survey.
3. 12.13.3 Frequency. Surveys will be conducted on an annual basis. Conducting the survey annually should help detect any major change in the prevalence, incidence, and/or location of reported symptoms.
5. 12.14 Low ergonomic risk jobs. This company will compile a list of light-duty jobs. Jobs will be analyzed to determine the physical procedures used in the performance of each job, including lifting requirements, postures, hand grips, and frequency of repetitive motion. For such jobs, the ergonomic risk will be described. This information will assist healthcare providers in recommending assignments to light- or restricted-duty jobs. The light-duty job should therefore not increase ergonomic stress on the same muscle–tendon groups. Supervisors should periodically review and update the lists.
Low Ergonomic Risk Job Listing
Department |
Task/Job |
Date Evaluated |
||||||||||||||||||||||||||||
___________________ | _______________ |
6. 12.15 High ergonomic risk jobs. This company will compile a list of high ergonomic risk jobs. Jobs will be analyzed to determine the physical procedures used in the performance of each job, including lifting requirements, postures, hand grips, and frequency of repetitive motion. For such jobs, the ergonomic risk will be described. This information will assist healthcare providers in determining jobs from which assignments to light- or restricted-duty jobs may be necessary. Supervisors should periodically review and update the lists.
High Ergonomic Risk Job Listing
2. 13. Training and education. The purpose of training and education is to ensure that our employees are sufficiently informed about the ergonomic hazards to which they may be exposed and thus are able to participate actively in their own protection.
1. 13.1 Employees
1. will be adequately trained about the (YOUR COMPANY)’s ergonomics program. Proper training will allow managers, supervisors, and employees to understand ergonomic and other hazards associated with a job or production process, hazard prevention and control, and their medical consequences. The training program should include the following individuals:
1. 13.1.1 All affected employees
2. 13.1.2 Engineers and maintenance personnel
3. 13.1.3 Supervisors
4. 13.1.4 Managers
5. 13.1.5 Healthcare providers.
2. 13.2 Program design. The program will be designed and implemented by ____________________________. Appropriate special training should be provided for personnel responsible for administering the program.
3. 13.3 Learning level. The program will be presented in language and at a level of understanding appropriate for the individuals being trained. It will provide an overview of the potential risk of illnesses and injuries, causes and early symptoms, means of prevention, and treatment.
4. 13.4 Evaluation. The program will also include a means for adequately evaluating its effectiveness. This will be achieved by using combinations of the following:
1. 13.4.1 Employee interviews
2. 13.4.2 Testing methods
3. 13.4.3 Observation of work practices.
5. 13.5 Training for affected employees will consist of both general and specific job training:
1. 13.5.1 General training. Employees who are potentially exposed to ergonomic hazards will be given formal instruction on the hazards associated with their jobs and with their equipment. This will include information on the varieties of hazards associated with the job, what risk factors cause or contribute to them, how to recognize and report symptoms, and how to prevent these disorders. This instruction will be repeated for each employee as necessary. This training will be conducted on an annual basis. (OSHA’s experience indicates that, at a minimum, annual retraining is advisable).
2. 13.5.2 Job-specific training. New employees and reassigned workers will receive an initial orientation and hands-on training prior to being placed in a full-production job. Training lines may be used for this purpose. Each new hire will receive a demonstration of the proper use of and procedures for all tools and equipment. The initial training program will include the following:
1. 13.5.2.1 Care, use, and handling techniques pertaining to tools
2. 13.5.2.2 Use of special tools and devices associated with individual work stations
3. 13.5.2.3 Use of appropriate guards and safety equipment, including personal protective equipment
4. 13.5.2.4 Use of proper lifting techniques and devices
6. 13.6 Training for supervisors. Supervisors are responsible for ensuring that employees follow safe work practices and receive appropriate training to enable them to do this. Supervisors, therefore, will undergo training comparable to that of the employees, and such additional training as will enable them to recognize early signs and symptoms of ergonomic stressors, to recognize hazardous work practices, to correct such practices, and to reinforce the ABC ergonomic program, especially through the ergonomic training of employees as may be needed.
7. 13.7 Training for managers. Managers will be made aware of their safety and health responsibilities and will receive sufficient training pertaining to ergonomic issues at each work station, and in the production process as a whole, so that they can effectively carry out their responsibilities.
8. 13.8 Training for engineers and maintenance personnel. Plant engineers and maintenance personnel will be trained in the prevention and correction of ergonomic hazards through job and work station design and proper maintenance, both in general and as applied to the specific conditions of the facility.
9. 13.9 Employee training and education. Company healthcare providers will participate in the training and education of all employees. This training will be reinforced during workplace walk-throughs and the individual health surveillance appointments. All new employees will be given such education during orientation. This demonstration of concern and the distribution of information should facilitate the early recognition of CTDs prior to the development of more severe and disabling conditions and increase the likelihood of compliance with prevention and treatment.
1. 13.9.1 Early report of symptoms. Employees will be encouraged by healthcare providers and supervisors to report early signs and symptoms of CTDs to the in-plant health facility or ______________________ (predesignated authority). This will allow for timely and appropriate evaluation and treatment. Supervisors and managers at all levels will be careful to avoid any potential disincentives for employee reporting, such as limits on the number of times an employee may visit the health unit.
2. 14. Definitions. A wide variety of terms are currently used by employers, occupational safety and health professionals, and others in describing ergonomic programs. The following definitions are provided to clarify the terms used by OSHA in their ergonomic program management guidelines:
. Cumulative trauma disorders (CTDs) is the term used in these guidelines for health disorders arising from repeated biomechanical stress due to ergonomic hazards. Other terms that have been used for such disorders include “repetitive motion injury,” “occupational overuse syndrome,” and “repetitive strain injury.” CTDs are a class of musculoskeletal disorders involving damage to the tendons, tendon sheaths, synovial lubrication of the tendon sheaths, and the related bones, muscles, and nerves of the hands, wrists, elbows, shoulders, neck, and back. The more frequently occurring occupationally induced disorders in this class include carpal tunnel syndrome, epicondylitis (tennis elbow), tendonitis, tenosynovitis, synovitis, stenosing tenosynovitis of the finger, DeQuervain’s disease, and low back pain.
. Ergonomic hazards refer to workplace conditions that pose a biomechanical stress to the worker. Such hazardous workplace conditions include, but are not limited to, faulty work station layout, improper work methods, improper tools, excessive tool vibration, and job design problems that include aspects of work flow, line speed, posture and force required, work/rest regimens, and repetition rate. They are also referred to as “stressors.”
. Ergonomic risk factors are conditions of a job, process, or operation that contribute to the risk of developing CTDs.
. Ergonomics Team/Committee refers to those responsible for identifying and correcting ergonomic hazards in the workplace, including ergonomic professionals or other qualified persons, healthcare providers, engineers and other support personnel, plant safety and health personnel, managers, supervisors, and employees.
. Ergonomist or ergonomics professional means a person who possesses a recognized degree or professional credentials in ergonomics or a closely allied field (such as human factors engineering) and who has demonstrated, through knowledge and experience, the ability to identify and recommend effective means of correction for ergonomic hazards in the workplace.
. Healthcare provider is a physician who specializes in occupational medicine, or a registered nurse specializing in occupational health, or other health personnel (such as emergency medical technicians) working under the supervision of a physician or registered nurse. Healthcare providers will have the training outlined in
Appendix B
, “Medical Management Program.”
. Qualified person means one who has thorough training and experience sufficient to identify ergonomic hazards in the workplace and recommend an effective means of correction. An example would be a plant engineer fully trained in ergonomics.
. Systems approach to safety and health management means a comprehensive program by the employer that addresses workplace processes, operations, and conditions as interdependent systems in order to identify and to eliminate or reduce all types of hazards to employees. Thus, complex ergonomic problems may require a combination of solutions.
REVIEW QUESTIONS
1. List five MSD problem identifiers.
2. What are the benefits of worker involvement in an ergonomics program?
3. Who should participate in a good ergonomics program?
4. What are some of the risk factors to look for in a job/task?
1. What is a job analysis? List some of the steps involved in performing a job analysis?
2. What are some of the return on investment methods?
REFERENCES
1. Bureau of Labor Statistics (2011). USDL-11-16-12. News Release.
2. Liberty Mutual Insurance Company. Manual Materials Handling.
3. NIOSH (1981). Work Practices Guide for Manual Lifting. Cincinnati, OH.
4. OSHA, O. S. (n.d.). Retrieved February 2015, from Occupational Safety and Health Administration:
http://www.osha.gov./SLTC/ergonomics/controlhazards.html
.
5. Six Sigma Costs and Savings. (n.d.). Retrieved 2015, from Six Sigma:
.
CHAPTER 7
BIOMECHANICS
LEARNING OBJECTIVES
At the end of this module, students will be able to describe the basic elements of biomechanics as they relate to the human body.
INTRODUCTION
Biomechanics is the study of forces on the human body (Marras, 2006). Every task from the gait of the physically handicapped, the lifting of a load by a factory worker, to the performance of an athlete can be described in terms of the specific movements and loading, both muscular and structural (Winter, 1990). The specific movements and loading on the musculoskeletal system change from case to case.
BACKGROUND
Why Is Biomechanics Important to Ergonomics?
Biomechanics is a useful tool in situations
where
lifting, pushing, or pulling is performed with or without a load. In certain body postures, the body’s own weight creates postural stress. The goal of occupational biomechanics is to quantitatively describe the musculoskeletal loading that occurs during work, in order to derive the degree of risk associated with the task.
The Body Described as Levers
A major assumption of occupational biomechanics is that the body behaves according to the laws of Newtonian mechanics. Movement in the body is produced by a system of levers. The levers work together to produce coordinated action, some by actual movement (dynamic) and others by stabilization (static).
BIOMECHANICS OF THE HUMAN BODY
Parts of a Lever System
The following explanation of levers, as applied to the human body, is a simplified version to help all students understand the correlation between body posture and forces. Figures
7.1
and
7.2
explain the basic parts of a lever system.
Figure 7.1
Parts of a free body diagram
Figure 7.2
Parts of a lever system as displayed on the human body
Free body and force diagrams used.
· Fulcrum: pivot about which a Lever turns. In the human body, this is typically the joint center.
· Lever: rigid bar that turns about an axis of rotation or Fulcrum. In the human body, this is typically a combination of body parts, a limb for example (what anthropometry calls the bodies link lengths).
· Lever arm: distance from the fulcrum to either the load or the effort.
· Load:
applied force. In the human body, this can be the weight of the object in the hand, as well as the limb weight.
· Effort:
resistance force. In the human body, this is the force generated by the musculoskeletal system that is applied to cause movement against load and/or stabilize a joint.
Classes of Levers in the Human Body
The class of lever is determined by the relative position of the load or applied force, fulcrum, and effort force, as shown in
Figure 7.3
.
· In a first-class lever, the load and effort are at opposing ends of the lever and the fulcrum is located in the center, for example, a child’s see saw. When the effort is applied, the load moves in the opposite direction.
· The skull is a human example
· In a second-class lever, the fulcrum and effort are at opposing ends of the lever and the load is located in the center, for example, a wheelbarrow. When the effort is applied, the load moves in the same direction.
· The foot is a human example
· In a third-class lever, the fulcrum and load are at opposing ends of the lever and the effort is located in the center, for example, a staple remover. When the effort is applied, the load moves in the same direction.
· The bent arm is a human example.
Figure 7.3
This figure displays the relationship between simple levers and the human body during static loading
BIOMECHANICS MADE SIMPLE
Biomechanical loads or stresses on the body are not defined purely by the magnitude of the weight or applied load. The position of the weight relative to the fulcrum (or point rotation of the joint) and direction of force defines the muscular effort required by the body. For example, as shown in
Figure 7.4
, holding a 40 lb dumbbell does not produce 40 lb of force on the elbow, nor does the bicep respond with 40 lb of force. It does, however, create a tendency for the system to rotate, and those rotational forces are called moments.
Figure 7.4
Holding a 40-lb weight results in 480 in.-lb of clockwise rotational force, the moment, at the elbow. The body must respond counterclockwise effort caused by the muscles contractile force
Let’s Take a Moment
The measure of a force’s tendency to cause a body to rotate about a specific point, that is, rotational force is a moment. A moment is a vector quantity having both direction and magnitude. A moment is defined as the product of the applied force and the perpendicular distance (lever arm) through which the force is applied. The perpendicular distance between the fulcrum and the effort is the muscle effort lever arm; the perpendicular distance between the fulcrum and the load is the load lever arm.
Moments are commonly expressed in Newton-meters (N m). A Newton is a unit of force that takes mass into consideration. One Newton is equal to 0.225 lb. Moments can also be expressed as inch-pounds or foot-pounds.
While this method is simplistic, the general relation of forces acting and the body’s reaction to them is sound. For the purposes of this chapter, a moment or rotational force is the product of weight and distance.
(D) Distance (or moment arm or lever arm) is the measurement from the point of rotation perpendicular to the direction of the applied weight or load. In
Figure 7.5
, the distance from the elbow to the object being held in the hand is applied force lever arm. Distance is expressed in inches (in.).
Figure 7.5
Moment (or force) = weight × distance
(W) Weight is the force generated by the gravitational attraction of the earth on the mass of an object. Weight is expressed in pound-force (lb) as opposed to pound-mass (lbm). In the example from
Figure 7.5
, a third-class lever can be seen in the arm with the point of rotation or fulcrum at the elbow.
Holding a weight in the hand creates a moment around the elbow, tending to make it extend. Muscles spanning the elbow create the opposite moment by contracting, so that the elbow is able to support the weight; the greater the weight in the hands, the larger the moment at the elbow.
Holding a 40-lb object in the hand produces a 480 in. lb (.) of rotational force at the elbow (
Figure 7.5
). The rotational force created by the effort must be equal in magnitude to a 480 in. lb to stop rotation, but applied in the opposite or counterclockwise direction (
Figure 7.6
).
Figure 7.6
To stabilize a joint the resultant or muscle force (Mm) must equal the applied force (Ma)
This 480 in. lb applied moment from the load results in the muscle responding with 960 lb of effort (
Figure 7.7
).
Figure 7.7
Resultant or muscle force is significantly higher than applied force
As inferred in this example, the longer the distance between the object and the point of rotation, the greater the rotational force or moment. When lifting an object, the point of rotation in the torso is the
L5/S1
spinal unit. The lever arm or distance is measured from the L5/S1 vertebra to the object in the hands, reference
Figure 7.8
.
Figure 7.8
The spine as a third-class lever system (Adapted with permission The Ergonomics Image Gallery)
If rotational force or moment = weight × distance, how much rotational force or moment is generated on the L5/S1 spinal unit when the 40 lb weight is lifted?
It Depends on the Distance!
· Holding 40 lb, 20 in. from the L5/S1 results in 800 in. lb of rotational force.
· Holding 40 lb, 15 in. from the L5/S1 results in 600 in. lb of rotational force.
· Holding 40 lb, 10 in. from the L5/S1 results in 400 in. lb of rotational force.
Clearly, a practical application to understanding the forces on the body is demonstrated. Reducing the distance from the load to the point of rotation reduces the applied rotational forces on the spine. In other words, when lifting, the load should be held as close to the body as possible.
The muscles in our body need to generate the same amount of rotational force, in the opposite direction, to keep the body from rotating. The lever arm in the spine, the distance from the fulcrum to the muscle attachment, is small. Therefore, the muscle must generate a force greater than that which is held in the hands.
Third-Class Lever
The musculoskeletal system can be represented by a lever system. Three types are present in the human body. Most of the joint rotations in our body behave as a third-class lever. A third-class lever has the benefit of good range of motion, speed, and power. However, large muscle forces are required to move even a small amount of weight.
In a third-class lever, the point of rotation or fulcrum is located at one end of the system. The applied load acts on the other end of the system and the force (muscle force) acts between the two (Figure 7.5).
A third-class lever system puts the body at a biomechanical disadvantage because the muscles have to generate considerably more rotational force than the rotational force generated by the load. This is because the distance from the point of rotation to the muscle action (muscle lever arm) is smaller than the distance from the point of rotation to load (applied lever arm).
The same lever system is found in the spine; the point of rotation or fulcrum is the L5/S1 spinal unit. The distance from the muscle attachment point to the L5/S1 is approximately 1 in. (see
Figure 7.9
). Given our greatest effort, we can never bring the load any closer to our spine than the depth of our torso.
Figure 7.9
The spine as a third-class lever system displaying that the further the load is from body the higher the forces on the spine (The Ergonomics Image Gallery)
To keep the weight of the object from bending the torso forward, the muscles need to generate a moment equal in magnitude to the moment of the applied weight (i.e., the load).
Figure 7.9 illustrates that holding 40 lb, 20 in. from the L5/S1 results in 800 in. lb moment. To calculate the forces on the spine:
Figure 7.9 illustrates that the muscles generate 800 lb. of force to statically hold a 40-lb weight and that the muscles of the spine are at a biomechanical disadvantage. To increase the biomechanical advantage of the spine, keep the weight located close to the body, as this decreases the lever arm (D) of the applied force.
When bending to pick up a load, the weight of the torso adds considerably to the applied force especially if lifting in an awkward posture. The torso contains approximately 60% of your body weight. A 200-lb person carries 120 lb in their torso.
The moment or rotational force is calculated the same way (i.e., ). The distance in this example is the distance from the L5/S1 spinal unit to the center of gravity of the torso. Note these calculations are simplified to illustrate the ratio of applied force to muscle force.
The moment of the body . or . This value is added to the applied moment (Ma) or . To solve for forces acting on the spine when bending forward to lift:
where
Keeping the spine in a neutral posture reduces the muscle contraction forces and thus the forces on the spinal unit. In this example, the muscles generate 1520 lb of force to statically hold a 40-lb weight because of the added force caused by the weight of the torso when leaning forward. Clearly, the muscles are at a biomechanical disadvantage.
To increase the biomechanical advantage of the spine, keep the weight located close to the body, as this decreases the lever arm of the applied force (Ma), and keep the ears over the shoulders and shoulders over the hips to limit the contribution of the torso to the applied forces.
Figure 7.10
shows an extraordinarily difficult posture to maintain for lifting.
Figure 7.10
Awkward lifting posture results in high spinal loading
Second-Class Lever
A second-class lever has the fulcrum on one end, the muscle force or effort on the other, and the load between the two. A wheel barrel or nutcracker is an example of a second-class lever (see Figure 7.3). In the body, the foot is a second-class lever; the ball of the foot acts as the fulcrum or point of rotation. The load is applied through the tibia (or lower leg bone) and the muscle force is applied through the gastronomies or calf muscle.
The muscle has the biomechanical advantage in this lever system due to the length of the lever arm between the point of rotation and the muscle force. Relatively little muscle force is necessary to move a heavy weight (refer to
Figure 7.11
).
Figure 7.11
In the body, your foot has the mechanical advantage; this is an example of a second-class lever
How much muscle force does it take to move a 200-lb person? The distance from the ball of the foot (fulcrum) to the tibia is assumed to be 6.5 in. (for a 6-ft man of average build who weighs 200 lb).
To calculate the applied moment:
To move the body, the calf muscle needs to generate a moment equal in magnitude to the moment of the applied weight but in the opposite direction; the body weight is pulling the foot downward, while the calf is lifting the foot up.
The muscles in a second-class lever system have the mechanical advantage. In this example, the muscles generate 1
62
.5 lb of force to move a 200-lb person (see
Figure 7.12
).
Figure 7.12
Second-class lever in the foot give us a biomechanical advantage, our muscles contract with far less force than is required to move the body
First-Class Lever
First-class levers are those that have a fulcrum in the middle of the system, an applied load on one end, and an opposing (muscle) force on the opposite end of the system. Sea saws, crowbars, and scissors are examples of a first-class lever (see
Figures 7.3
and
7.13
). This type of lever results in balanced movement, good force, and range of motion. Our skull is an example of a first-class lever in the body.
Figure 7.13
A first-class lever can be found in the skull
The applied force is the center of gravity of the skull located in the proximity of the chin, the fulcrum is the joint between the skull and the spine, and the muscle force is actuated by the muscles on the back of the head or neck that tilt the head backward.
How much muscle force does it take to hold my head in a neutral posture? Using the same 200 lb male, the distance from the center of the skull (fulcrum) to the chin (assumed center of gravity of the head) is 4 in. In addition, the average adult head weighs between 15 and 21 lb, for this example, we will use 18 lb.
To calculate the moment created by the applied weight (the skull) reference Figure 7.13:
To stabilize the head in a neutral posture, neck muscle needs to generate a moment equal in magnitude to the moment of the applied weight.
In a first-class lever system, neither the muscles nor the load have the mechanical advantage as long as the head is held in a neutral posture. From this example,
Figure 7.14
, it is easy to see that the further the head leans forward, the greater the contribution of the applied moment and thus the greater the muscle force required to maintain the posture.
Figure 7.14
The loading tray has a straight handle that results in a deviated write posture, change the angle of the handle would result in a neutral posture and less stress on the wrists
Back Injury Prevention Rules of Thumb
· If the load is not close, the pressure is gross.
· If the back is bent, one will not prevent.
· If muscles are slack, you will hurt your back.
SUMMARY
The goal of occupational biomechanics is to describe the degree of postural stresses on the body. A basic understanding of the degree of postural stress a person experiences is beneficial to the ergonomic practitioner for recognizing where workplace, tool, or task enhancements will best benefit the worker and the employer.
CASE STUDY
Recommend searching
www.youtube.com
for “firing of the M198 Howitzer” to gain a better understanding of the highly repetitive and physical nature of this drill coupled with the heavy weight and high number of rounds fired. More detailed information can also be found in the Case Study
Chapter 16
.
The United States Marine Corps Artillery Instructional Battery (AIB) stationed at The Basic School Marine Corps Base Quantico, VA, was experiencing a high rate of injuries and our ergonomics team (Dr Lee Ostrom, Dr Cheryl Wilhelmsen and Theresa Stack) was asked to perform an analysis of the “Call for Fire” operation to help determine why these injuries were occurring. We designed and carried out an ergonomics study to determine causes of these injuries. The study was carried out using data collection methods that would collect anthropometric, psychophysical, biomechanical, and human error data.
The “Call for Fire” exercise takes place over 3 days. During the first day, the AIB sets up the M198 Howitzers (see
Figure 7.15
). The ammunition is also delivered during day 1. Approximately 1100 rounds of 155 mm ammunition, fuses, and sufficient powder are brought to the site and staged behind each gun. Days 2 and 3 are when the actual firing of the guns occurs; each gun fires between 3
50
and 400 rounds of ammunition. The rounds weigh between 95 and 105 lb each depending on whether they contain high explosive or white phosphorus.
Figure 7.15
Biomechanical modeling of step 5 – moving the round from the pallet to the loading tray
The Marines move the rounds multiple times through the course of the 2-day shoots. Biomechanical modeling was used to determine if moving the rounds produces an increased risk of injury for the combination of force, posture, frequency, and duration.
Three-Dimensional Static Strength Prediction Program 6.0.2 (Michigan, 1999) was used to model the task as well as to compare the round weight, posture, frequency, and duration to the weight handling limits in MIL-STD 1472F (Defense, 1999).
The procedure for moving the round is as follows and can also be found on the Internet with the search term:
1. The fire instructions are radioed to the recorder.
2. The recorder announces the fire order.
3. The powder person adjusts the powder.
4. The type of round is verified.
5. A round is removed from the ready board and laid into the loading tray (Figure 7.11).
6. The two loaders pick up the round.
7. The rammer places the ram at the back of the round.
8. The breach is opened.
9. The loaders bring the round up to the breach, Figure 7.10.
10. The rammer pushes the round in the breach.
11. The loader on the right side of the loading tray releases his grip.
12. The other loader steps back and to the left of the gun.
13. The powder man brings up the powder and hands it to the A-gunner.
14. The A-gunner verifies the amount of powder and places it in the breach.
15. The A-gunner closes the breach and places a primer in the priming hole.
16. The lanyard is attached and then pulled.
17. The gun fires.
18. The A-gunner opens the breach and swabs the breach and breach plug.
Multiple steps were analyzed for the full study; as shown in
Table 7.1
, it was found that steps 5 and 6 produced the highest forces on the spine as well as the wrist.
Table 7.1
Loading Tray and Example of Changing the Angle on the Tray to Reduce the Force on the
Wrist
Body Segment |
Compressive Forces |
Result |
||
L5/S1 |
1762 lb |
Spinal compression fall above the action limit of 77 0 lb and is therefore considered above hazard threshold for that body segment |
||
Population Capable of Performing the Task (%) |
||||
Wrist |
23 |
Above hazard threshold |
||
Elbow |
75 |
Marginal |
||
Shoulder |
50 | |||
Torso |
77 |
Below hazard threshold |
||
Hip |
62 | |||
Knee |
97 |
|||
Ankle |
84 |
To verify the results and provide an alternative evaluation, the Department of Defense Design Criteria Stand for Human Engineering (Defense, 1999; Section 5.9.11.3) was used (see
Tables 7.2
and
7.3
).
Table 7.2
Move One Round from Staging to Pallet and Move One Round from Pallet to Loading Tray
Round Weight (lb) |
Recommended Weight Limit (MIL-STD) (lb) |
Task Factors |
|||
64 |
Recommended weight limit for a one-man carry is 82 lb under optimal conditions |
Round weight exceeds recommended carrying weight, the task is therefore considered above hazard threshold |
Table 7.3
Moving the Round and the Loading Tray to the Gun (Start of Task)
136 |
Recommended weight limit for a two-man lift (below 36 in.) is 174 lb under optimal conditions |
Round weight does not exceed recommended lifting weight limit; the task is therefore considered below hazard threshold |
Based on the biomechanical modeling and comparison to the MIL-STD, moving the round from the pallet to loading tray produces an increased risk of injury to the wrists. Redesigning the carry tool may reduce these factors by improving not only the coupling of the hands to the tool but also the degree of hand/wrist deviation. Decreasing the frequency of moving the rounds from the staging area to the pallet, for example, by allowing the LTs to assist, would decrease the risk of injury to the low back and torso by allowing time for the soft tissues to rest and recover.
Moving the round from the pallet to the loading tray produces the greatest spinal compression due to the squatted posture and twisting motion. Elevating the loading tray improves the task characteristics. The only feasible way to reduce the risk of injury is to allow frequent task rotation.
Loading the gun with the loading tray produces a moderate risk of spinal injury. The risk factors can be greatly reduced by allowing for frequent task rotation. For example, decreasing the frequency of the exposure (using the MIL-STD) reduces the risk level from unsafe to safe. In other words, when loading the gun, it is the frequency of the exposure that is causing the risk.
The Marines received a full report and implemented solutions to reduce the physical demand on the service members.
KEY POINTS
· A person holding an object closer to the body results in lower rotational forces on the spine and thus lower muscle forces. The following is qualitative as there are many factors that affect the spinal loading.
·
·
·
· Movement in the body can be described by a system of levers.
· The levers work together to produce coordinated action, some by actual movement (dynamic), and others by stabilization (static).
· Biomechanical loads or stresses on the body are not purely defined by the magnitude of the weight.
· The longer the lever arm (the distance from the fulcrum to the applied weight), the greater the force.
REVIEW QUESTIONS
1. What are the three lever systems used to describe the human body?
2. Which lever system most represents the human spine?
3. If the load is positioned at arm’s length from the body, what happens to the forces on the spine?
4. What are the ways a person can reduce the forces on their spine without changing the weight of the load?
5. Which lever system is considered a biomechanical advantage to the human and why?
EXERCISE
1. Reference appendix.
REFERENCES
1. Department of Defense. (1999). MIL-STD-1472F, Department of Defense Design Criteria Standard: Human Engineering. United States Government Printing Office.
2. Marras, W. (2006). Fundamentals and Assessment Tools for Occupational Ergonomics 2nd edn. CRC Press.
3. University of Michigan. (1999). 3D Static Strength Prediction Program.
http://www.umich.edu/∼ioe/3DSSPP/background.html
.
4. Winter, D. (1990). Biomechanics and Motor Control of Human Movement, 2nd edn. Wiley-Interscience.
ADDITIONAL SOURCES
1. Chaffin, D. (2006). Occupational Biomechanics, 4th edn. Wiley-Interscience.
2. McGinnis, P. (2013). Biomechanics of Sport and Exercise, 3rd edn. Human Kinetics.
3. Peterson, D. R. (2014). Biomechanics: Principles and Practices. CRC Press.