ERGONOMICS

1. ERGONOMICS S.PK

2. INTRODUCTION • The association between occupations and musculoskeletal injuries was documented centuries ago. Bernardino Ramazinni (1633-1714) wrote about work-related complaints (that he saw in his medical practice) in the 1713supplement to his 1700 publication, "De Morbis Artificum (Diseases of Workers). • Presently, Work Related to Musculoskeletal Disorder and Human Error are considered the research challenges in ergonomics field.

3. INTRODUCTION • World War II, for the first time, technology and the human sciences were systematically applied in a coordinated manner. Physiol., psych., anthropol., doctors, scientists and engineers together addressed the problems arising from the operation of complex military equipment. • As this inter-disciplinary approach appeared so promising , the cooperation was pursued in industry even after the war. • Interest in the approach grew rapidly, especially in Europe and the United States , leading to the foundation in England of the first ever national ergonomics society in 1949,which is when the term ‘ERGONOMICS’ was adopted. • In 1961 International Ergonomics Association (IEA), was formed.

4. INTRODUCTION Ergonomicsmeans the natural lawsgoverning human work. The name Ergonomics came from the Greek words “ergon” = work “nomos” = natural laws.

5. Alternative terms for Ergonomics • The term ‘human factors’is often used in the USA • Humans Factors Engineering • Human Engineering • Occupational Psychology • Engineering Psychology • Applied Experimental Psychology

6. Modern Definition • Science of fitting workplace conditions and job demands to the capabilities of the working population. • Ergonomics is the laws of work that define the limits to human capability. The Basics of Ergonomics

7. Ergonomics is the study of the interaction between people and machines and the factors that affect the interaction. • Its purpose is to improve the performance of systems by improving Human-Machine interaction. • Ergonomists contribute to the design and evaluation of tasks, jobs, products, environments and systems in order to make them compatible with the needs, abilities and limitations of people. (Int.Erg.Asso.)

8. This can be achieved by ‘designing-in’a better interface • Designing the user –interface to make it more compatible with the task and the user. So that it become easier to use and more resistant to errors that people commonly make. Eg. • In an information processing task –redesign to reduce the load on the user’s memory by shifting more memory to the computer. • In a manual handling task redesigning aims to reduce the load on Musculoskeletal system by adding handles, changing the size & weight of the containers etc…

9. or By ‘designing-out’ factors • IN THE WORK ENVIRONMENT (noise,vibration,lighting,ventilation, seating,etc…) • THE TASK (make new task easier to learn and perform) • IN THE ORGANISATION OF WORK that reduces H-M performance.( the work environment should permit the workers to work at their own pace so as to reduces the ‘psychophysical stress’ of being “tied to the machine”)

10. Objectives • To enhance the efficiency and effectiveness with which the work and other activities are carried out. • To enhance the certain human values, including improved safety, reduced fatigue & stress, increased comfort, greater user expectation, increased job satisfaction and improve quality of life.

11. Ergonomics doctrine Six Pillars of Ergonomic Design “Wisdom” • User Orientation: Design and application of tools, procedures, and systems must be user-oriented, rather than just “task” oriented • Diversity: Recognition of diversity in human capabilities and limitations, rather than “stereotyping” workers/users • Effect on Humans: Tools, procedures, and systems are not “inert”, but do influence human behaviour and well-being Sanders M. S., and McCormick E. J.,1993

12. Ergonomics doctrine cnt.. • Objective Data:Empirical information and evaluation is key in design process, rather than just use of “common sense” • Scientific Method:test and retest hypothesis with real data, rather than “anecdotal” evidence or “good estimates” • Systems:object, procedures, environments, and people are interconnected, affect one another, and do not exist in “isolation” Sanders M. S., and McCormick E. J.,1993

13. Ergonomics - basic framework Task Demands Working Capacity Task Outcome Work Design

14. Working capacity • Age • Gender • Selection • Training • Lifestyle • Motivation • Adaptive Reserves

15. Task outcome • Performance • Productivity • Safety • Stress • Fatigue

16. Ergonomics: work design and adaptation • Task Design • Systems Design • Product Design • Workstation Design • Interface Design • Information Design • Environment Design

17. Branches of ergonomics • Physical ergonomics • Cognitive ergonomics • Organizational ergonomics

18. Physical ergonomics • Concerned with anatomical, anthropometric, physiological and biomechanical aspects of human –environment- interaction. This includes working postures, MMH, repetitive movements, WRMSDs, energy expenditure, workplace layout, safety and health • ….Work place intervention.

19. Work place interventions : Tools • OWAS –(Ovako Working -posture Analysing System) To register different work postures • RULA – Rapid Upper Limb Assessment • VIDAR – Video and computer based method for ergonomic assessment. • NIOSH-equation – MMH • 2DSSPP – 2 Dimensional Static Strength Prediction Program • 3DSSPP – 3 Dimensional Static Strength Prediction Program • EEPP – Energy Expenditure Prediction Program

20. Cognitive ergonomics • Concerned with mental processes, such as perception, memory, reasoning and motor response, as they affect interaction among humans and other elements of a system. Relevant topics include • mental workload, • decision-making, • skilled performance, • human-computer interaction, • human reliability, • work stress and training as these may relate to human-system design.

21. EVALUATION OF USABILITY OF WORKSTATION • Keystroke level model (KML) • Link analysis • Checklist • Predictive human error analysis (PHEA) • Observation • Questionnaire • Hierarchical task analysis (HTA) • Repertory grids • Task identification for error analysis (TAFEI) • Layout analysis • Interviews • Heuristics

22. Organizational /Macro-ergonomics • An approach that emphasizes a broad system view of design, examining organizational environments, culture, history, and work goals. • It deals with the physical design of tools and the environment. • It analyzes the whole system, finds how each element should be placed in the system, and considers all aspects for a fully efficient system. A misplaced element in the system can lead to total failure.

23. Employee and organizational profiling Role clarity, role efficacy and role stress Performance Occupational and lifestyle stress – (e.g., General Well Being questionnaire, Occupational Stress Indicator) Motivation level -(Job Diagnostic Survey) Changes in behavioral pattern Absenteeism

24. Multi-Disciplinary Nature of Ergonomics • Anatomy and Physiology • Engineering Psychology • Engineering • Anthropology • Biomechanics • Medicine

25. Applications of Ergonomics Anatomy Orthopedics Physiology Medicine Psychology Sociology Anthropometry Biomechanics Work Physiology Industrial Hygiene Management Labor Relations Industrial Engineering Bio-Engineering Systems Engineering Safety Engineering Military Engineering Computer-Aided Design

26. BENEFITS OF ERGONOMICS. The benefit of the well designed jobs, workplace, and equipment are • IMPROVED PRODUCTIVITY • SAFTY & HEALTH and • INCREASED SATISFACTION OF THE EMPLOYEES.

27. THE FOCUS OF ERGONOMICS The focus is on the interaction between the Human-Machine and the design of interface between H-M. Every time we use a tool or a machine. We interact with it via an interface (a handle, a steering wheel, input devises in computer etc.). We get feedback via an interface(dashboard in car, computer screen etc.) The design of these interface determines the easiness in handling. When faced with productivity problem, engineers might call for better machines, personnel management might call for better trained people, and the ergonomist call for a better interface &interaction between H-M.

28. Trying to find the best combination for the worker. If the right combination is not achieved it will lead to ergonomic problems. Focus of ergonomics cont. • The Task The Tool The Work Station and Environment The User /Operator (worker)

29. BASIC WORK SYSTEM • A simple work system consists of one Person(H), one Machine(M), and an Environment(E). • 6directional interactions are possible • Each of the components in the system may interact either directly or indirectly with others. For example the machine may change the environment (by noise, heat) and this can affect the person.

34. Common Interactions between the components of a work system. INTERACTIONS DESIGN ISSUES Display: Workspace Location of displays Display: Environment Effects of lighting, Vibration and Noise on legibility. Senses: Workspace Sensory access to task. Senses: Environment Environmental requirements for operation of senses. Processing: Environment Effects on perception and cognition. Processing: Organization Skill level,training,fatigue,motivation. Effectors: Workspace. Determination of work space envelope. Effectors: Environment Effects of vibration, and climate on effectors. Controls: Workspace Task description needed to optimize control layout. Control: Environment Effects of environment on usability of controls.

35. WHEN TO CONSULT AN ERGONOMIST. Workplace Indicators • Performance deterioration • Quality problems • Absenteeism/turnover • Complaints of fatigue and discomfort

36. Ergonomic Hazards (Risk Factors) NATURE & ENVIRONMENT • Awkward working postures • Static postures • Forceful exertions • Repetitive movements • Pace of work • Point pressures • Temperature extremes • Vibration ORGANIZATIONAL INFLUENCES • Wage system • Quality Control • Management-Labor Relations • Machine-paced vs. self-paced work • Overtime • Shift work • Rest breaks

37. Non-Work-Related Risk Factors • Physical conditioning • Medical conditions (e.g. diabetes, arthritis) • Pregnancy • Hobbies (hand-intensive or manual handling) RESULTING INJURIES ARE CALLED: • Cumulative Trauma Disorders(CTD), Or • Repetitive Strain Injuries(RSI), Or • Musculoskeletal Disorders(MSD)

38. ERGONOMIC STRESS AREAS Hip Knee

39. FACTORS IN ERGONOMCS • Monitors placed too close or too far away may cause you to assume awkward body positions that can lead to eyestrain. • Viewing distances that are too long can cause you to lean forward and strain to see small text. This can fatigue the eyes and place stress on the torso because the backrest is no longer providing support.

40. When the monitor is too high, for example, you have to work with your head and neck tilted back. Working in these awkward postures for a prolonged period fatigues the muscles that support the head. • Potential Hazard • Working with your head and neck turned to the side for a prolonged period loads neck muscles unevenly and increases fatigue and pain.

41. The keyboard tray should1. be adjustable in height and tilt,2. provide adequate leg and foot clearance, and3. have adequate space for multiple input devices (eg. keyboard ,Mouse).The keyboard's vertical position should be maintained within the recommended range shown. The tilt of the keyboard may need to be raised or lowered using the keyboard feet to maintain straight, neutral wrist postures while accommodating changes in arm angles.

42. Deviations of the wrist Extension of the wrist • Reduce awkward wrist angles by lowering or raising the keyboard or chair to achieve a neutral wrist posture. • Elevate the back or front of keyboards to achieve a neutral wrist posture. • Eg: if the operator sits lower in relation to the keyboard, slightly elevating the back of the keyboard may help maintain a neutral wrist. Similarly, raising the front of the keyboard may help maintain neutral wrist postures for users who type with the keyboard in a lower position. Do not use keyboard feet if they increase bending of the wrist

43. Pointing devices such as a mouse now come in many sizes, shapes, and configurations. In addition to the conventional mouse, there are trackballs, touch pads, and finger tip joysticks. Selection and placement of a pointer/mouse is an important factor in creating a safe computer workstation.Consider the following factors in when evaluating your computer workstation.

44. Mouse placed too far from the user and not in the same plane as the key board.(2) Mouse placement that is too far away because of keyboard.(1) If the pointer/mouse is not near the keyboard (Figure 1) you may be exposed to awkward postures, contact stress, or forceful hand exertions while using the device. Working in this position (Figure 2) for prolonged periods places stress on the shoulder and arm which may lead to musculoskeletal disorders.

45. Substitute keystrokes for mousing tasks, such as Ctrl+S to save, and Ctrl+P to print • Use a keyboard that has a pointing device, such as a touchpad. • Use a keyboard without a ten-key pad, which leaves more room for the pointer/mouse. • Install keyboard trays that are large enough to hold both the keyboard and mouse. • Use a mouse pad with a wrist/palm rest to promote neutral wrist posture

46. Hands should move freely and be elevated above the wrist/palm rest while typing. When resting, the pad should contact the heel or palm of hand, not the wrist. • If used, wrist/palm rests should be part of an ergonomically-coordinated computer workstation. • Reduce bending of the wrists by adjusting other workstation components (chair, desk, keyboard) so the wrist can maintain an in-line, neutral posture. • Match the wrist support to the width, height, and slope of the front edge of the keyboard (keeping in mind that the goal is to keep wrist postures as straight as possible). • Provide wrist/palm supports that are fairly soft and rounded to minimize pressure on the wrist. The support should be at least 1.5 inches (3.8 cm) deep.

47. POOR MOUSE AND KEY BOARD PLACEMENT BECAUSE OF DESK TOP CLUTTER • Work surface depth should allow you to: • View the monitor at a distance of at least 20 inches (50 cm), and • Position the monitor to achieve the appropriate viewing angle, which is generally directly in front of the operator.

48. Bifocal users typically view the monitor through the bottom portion of their lenses. This causes them to tilt the head backward to see a monitor that may otherwise be appropriately placed. As with a monitor that is too high, this can fatigue muscles that support the head.  Possible Solutions Lower the monitor (below recommendations for non-bifocal users) so you can maintain appropriate neck postures. You may need to tilt the monitor screen up toward you. Raise the chair height until you can view the monitor without tilting your head back. You may have to raise the keyboard and use a foot rest. Use a pair of single-vision lenses with a focal length designed for computer work.  This will eliminate the need to look through the bottom portion of the lens

49. CONTACT STRESS FROM THE TABLE EDGE • Some desks and computer equipment have hard, angled leading edges that come in contact with a user's arm or wrist. This can create contact stress, affecting nerves and blood vessels, possibly causing tingling and sore fingers.

50. AWKWARD NECK POSTURES • Use height-adjustable work platforms so employees can be raised or lowered to minimize forward or backward head movements.