ASP Exam Study Guide
Ergonomics – Human Factors
Ergonomics questions comprise 13% of the ASP Safety Fundamentals Exam. Safety Professionals preparing to take the ASP & CSP Exams should be prepared to answer questions regarding ergonomic risk factors, work and workplace design, fitness for duty, monitoring and measuring of ergonomics, and ergonomic controls. This portion of our ASP Exam Study guide discussed human factors within ergonomics. Please see our other pages or the full study guide for information on ergonomic measurements and control methods.
Introduction to Ergonomics
Ergonomics, which has become a considerable concern for safety professionals, is the relationship between people and their environment, including materials, tools, equipment, surfaces, and other items which impact our ability to comfortably function in our environment, whether at work or at play. A workplace constructed with solid ergonomic principles in mind can encourage more productivity, lowered incident rates, and greater overall performance.
Ergonomics is applied through design. As a result, designers and engineers need to understand human behaviors, physiology, bio mechanics, kinesiology, and other fields which will impact elements of their design. Designs must account for normal uses, but also potential misuses, maintenance needs, and future repairs.
A few general principles of ergonomics apply to a wide variety of situations:
- People Vs. Machines – People and machines have different functions and capabilities, neither is always efficient at every function. For example, people can reason inductively and learn from past experiences, while machines excel at precise, repetitive operations and storing large amounts of data.
- Design the Job to Fit the Person – Humans have limited abilities, and failure to recognize these limitations can create hazards.
- Work Smarter, Not Harder – Productivity can be increased through evaluating job designs and making changes that result in reduced effort.
- People are Different – We are all individuals with different heights, weights, reaction times, strengths, and weaknesses. Job designs should take this into account.
Fitness for Duty
It’s critical that individuals in the workplace are prepared to perform the work that will be asked of them. This is the core principle of fitness for duty. Typically while developing job duties, basic criteria should be developed which an employee should meet to ensure he or she is fit for duty. Additionally, fitness for duty can become far more specific as fitness for performing specific functions becomes increasingly important. This is particularly true for specialized trades which require rigorous strength and stamina.
Fitness for duty can also refer to an employee returning to work after time off due to injury or illness. In these cases, qualitative testing can be performed which will determine an individuals fitness for duty.
Organizational, Behavioral, and Psychological Influences
The human factors theory of incident causation states that incidents are generally caused by human error as a result of:
- Inappropriate activities that are unnecessary to complete a job task or performing tasks for which an employee is not trained or authorized
- Inappropriate response to a stimulus that causes an accident or increases the severity of the outcome.
- Overload, particularly when a person’s responsibilities are greater than their capacity.
- Capacity can be expanded through training and experience.
- Capacity can be affected by the clarity of instructions, perception of risk, and environmental factors such as noise levels and temperature extremes.
Each of the following can contribute to workplace accidents, absenteeism, errors, and lower productivity:
Powerlessness – Workers feel that they cannot control their work environment
Mindlessness – Workers feel that thinking is not necessary to perform their job functions
Normlessness – Workers feel disconnected from societal norms and rules
Meaninglessness – Workers feel disconnected from their work and from the product they are producing
Workplace Stressors and Risk Factors
Ergonomic stressors can be abundant in the workplace if ergonomics were not factored into the design phase. Among these, repetitive strain and soft tissue injuries tend to be the most common from an ergonomics perspective. Repetitive strain injuries, such as carpal tunnel syndrome, are the result of cumulative trauma to the body’s tendons, ligaments, nerves, and other soft tissue injuries. Here’s a few of the most common:
- Tendinitis – inflammation or irritation of a tendon which causes pain or tenderness just outside of a joint.
- Carpal Tunnel Syndrome – A hand and arm condition that causes numbness and tingling, typically as a result of pinched nerves in the wrist.
- Raynaud’s Disease – Some areas of the body, such as fingers and toes, feel numb and cold in response to cold temperatures or stress.
- Fibromyalgia – a disorder characterized by widespread musculoskeletal pain, sometimes accompanied by fatigue, sleep, memory, and mood issues.
Emotional stress in the workplace can result in severe emotional issues for workers, including behavioral problems, anxiety, aggression, and cognitive issues such as problems concentrating or making decisions. Workplace stress is usually a result of placing employees in positions for which they are unprepared for or lack motivation for. Working conditions such as lack of control over responsibilities, unpredictable work schedules or intense on-call schedules, and tension in the workplace all contribute to stress.
Video Display Terminals (VDT)
With the reliance on computers in the workplace, the use of video display terminals has become increasingly common. The use of computer monitors has been linked to eye fatigue, blurred vision, nervousness, and eyestrain. Additionally, the use of computers and keyboards can lead to cumulative trauma disorders such as carpal tunnel syndrome. Setting up workstations using some basic ergonomic principles can greatly reduce the frequency of problems related to VDT use.
- Place the screen and keyboard at the proper height, with both directly in front of the user. The screen should be centered about 20* below horizontal for the best viewing angle.
- Take frequent breaks and change activities if you will be working at a computer for 1 hour or more.
- Ensure the monitor is adjusted properly for brightness, allowing text to be read easily.
- Ergonomic keyboards and keyboard pads are available that will reduce strain on the hands and wrists.
The principles of anthropometry, displays, controls, biomechanics, and all other aspects of ergonomics should be implemented into workstation design. Workstations should be designed to make work easy for employees. Comfortable employees are more productive and safer. The following principles should be considered when designing workstations:
- Frequency Principle – Materials or equipment that are used frequently should be conveniently located and easy moved / manipulated.
- Function Principle – Tools and equipment that function together should be located close to one another to limit how far they must be moved.
- Work Sequence Principle – Tools or materials that function together or in a specific sequence should be grouped together and with that sequence in mind.
- Importance Principle – The more important a tool or piece of equipment is to a job function, the more conveniently it should be located.
In addition, work stations should be designed with the user in mind. The following techniques can ensure workstations are designed appropriately.
- The reach for tools or equipment should be designed with the smallest users in mind.
- Workstations should be designed to be adjustable for individual needs.
- Work processes should be easy to understand and not be overly repetitive or physically demanding.
- The right tool for the job should be available and properly maintained.
- Work areas should be designed for daily use, but also for maintenance activities that are required periodically.
The Changing Workforce
The workforce is ever-changing, but currently two changes are most notable from an ergonomics standpoint:
- The workforce is aging as the average age of the US population increases. Typically, our physical capabilities diminish as we age. Strength, range of motion, duration of activity, and vision and hearing issues can all cause ergonomic concerns in the workplace. As a result, workstations must be designed with these issues in mind.
- Women in the workforce are capable of performing the same jobs that men are, but may find it more difficult to find workstations designed for smaller statures. Additionally, it may prove difficult to find certain types of PPE designed for women.