Aneri_09_PDIS_Seminar-Work Ergonomics.pptx

Work Ergonomics

1. Seminar Topic Name WORK ERGONOMICS Name : Mrs. Aneri Desai Roll No. : 19304922009 Course Name : PDIS Centre Name : RIL, Hazira Subject Name : Project (With Seminar)

2. What is Ergonomics? ERGO = “ W ork” NOMICS = “ R ules ” or “Laws” Ergonomics literally means “The L aws of Work” In other words Ergonomics means “Fitting the Job to the Worker ,” including: Work S tations Tools Equipment

3. OSHA defines ergonomics as the science of “ designing the job to fit the worker, instead of forcing the worker to fit the job. ”

4. SO EXACTLY WHAT IS ERGONOMICS? It is study of people efficiency at their working environment. It is one of the definition of Ergonomics. It is understandable that there are different definitions because ergonomics is all about differences

5. ERGONOMICS is a way of working smarter N ot harder by designing tools, equipment , work stations and tasks that allow a job to fit the worker and….. NOT by fitting the worker to the job.

6. DIFFERENCES This are differences in size, shape, strength and ability of individual workers. This differences call for different designs in equipment , furniture, Workstations and routines .

7. ERGONOMICS Ergonomics is used in a workplace to help prevent repetitive and cumulative injuries .

8. Object of Ergonomics The object of ergonomics is “to achieve the best mutual adjustment of man and his work to improve his convenience, efficiency and well being” Ergonomic approach includes designing of machines, tools, controls, equipments, processes, layout, housekeeping etc. to increase efficiency of both – man and the machine. Application of ergonomics reduces accidents and improves health and efficiency. Successful application is measured by improved efficiency, safety, productivity and acceptance of the ergonomic design. Human factors (HF) was the old discipline concerned with how humans react with their work tasks and environment aiming to make the relationship safer, healthier and more efficient. The new name of this discipline is Ergonomics. Previously known 'Human Engineer' or "Engineering Psychologist" is now known as "Ergonomist or Ergonomicist (in great Britain). The term Ergonomics is biotechnological and covers the same scope and complexity of interests that human factors embraces. Therefore, human factors are the main constituents of ergonomics. For main division of factors affecting work including human factors see in a schematic diagram they are shown in next slide.

9. Work Performance or Man at work Physical Factors Human Factors W o r k l oad P o s tu r e Physical Work Physical E n vi r onm e n t Heat Light No ise Vibration Dust, Fumes etc. Radiation Physiological Psychological Work Ca pac i ty W or k load Attitude Aptitude Mo t i v a t i on Boredom Fatigue etc.

10. Ergonomics studies the 'human factors' and designs the system or suggests application or modification of the existing system to make the work more suitable or convenient to the man at work. Thus In this context, for its procedural aspect, all human factors - physiological and psychological contribute in constituting the science. But from discipline point of view, main constituents of ergonomics are anatomy, physiology, psychology and engineering. Schematic diagram of disciplines {work areas) constituting the ergonomics is also shown in next slide:

11. Anthropometry Constituents of Ergonomics An a t o m y P h y sio l ogy Biomechanics Human Performance Theory Learning Theory Training Skill Theory Organisation Theory Work Design S y s t em Design Industrial Hygiene Psychology Engineering Management Work P h y sio l ogy E n vi r onm e n t Physiology Safety Engg. Bio Engg. S y s t em En gg . Mechanical or Ind. Engg. Computer Aided Design (CAD) Military Engg. etc.

12. Main Ergonomic Principles Work activities should permit worker to adopt several different healthy and safe postures. Muscle forces should be done by the largest appropriate muscle groups available Work activities s/b performed with joints at about mid-point of their ROM (esp. head, trunk, UE)

13. FACTS The average person working at a keyboard can perform 50,000 to 200,000 keystrokes a day Overexertion & falls are the most common cause of workplace injury An average of 125,000 back injuries due to improper lifting each year. Muscles overuse results in tiny tears in the muscles and scarring; these contribute to inflammation and muscle stiffness

14. Ergonomic Factors Two Categories of Ergonomic Factors 1. Environmental Hearing Vision General comfort and health 2. Physical

15. Environmental Factors Some examples of ergonomic environmental problems are: Sick Building Syndrome Excessive noise Improper lighting Temperature extremes

16. Physical Stressors Physical stressors place pressure or stress on parts of the body: Joints, muscles, nerves, tendons, bones Sometimes these injuries are referred to as “Cumulative Trauma Disorders” (CTDs) or “Repetitive Strain Injuries” (RSIs)

17. Types of Injuries Muscle pain Joint pain Swelling Numbness Restricted motion Repetitive stress injury Rep etitive motion injury Cumulative trauma disorder Musculoskeletal disorder

18. ERGONOMIC STRESS AREAS Knee Hip

19. Target Regions Back Upper extremities Lower extremities

20. Types of Problems or Mismatches Physical Size Endurance Strength Manipulative Environmental Cognitive

21. Physical Size Clearance Reach Equipment Size Personal Protective Equipment (PPE)

22. Cognitive Machine Pacing Shift Work Morale Psychosocial

23. Musculoskeletal Disorders: Signs and Symptoms Decreased grip and/or pinch strength Swelling Fatigue Loss of function Numbness Burning sensation Tingling Pain Cramping Stiffness

24. An ounce of Prevention is worth a pound of cure !

25. What to do ?? Warm up & stretch before activities that are repetitive, static or prolonged Take frequent breaks from ANY sustained posture every 20-30 minutes Respect pain positions or stop painful activity Recognize early signs of inflammatory process

26. Posture check Increased stress, decreased circulation…

27. Posture Think of posture in terms of joint position Static and awkward postures lead to: Decreased movement Decreased circulation Increased stress and fatigue

28. Maintain Neutral Posture Maintain erect position of back & neck without shoulders relaxed Position equipment & work directly in front of and close to your major tasks Avoid static positions for prolonged time; muscles fatigue- --MOVE to circulation!

29. Modify Tasks Alternate activities frequently; rotate heavy &/or repetitive tasks without lighter less repetitive ones. If stress become worse REASSESS task setup & look for alternative methods Avoid repetitive or prolonged grip activities

30. Correct & Incorrect Techniques

31. Computer workstation ergonomics Chair Monitor Keyboard Mouse Document holders Lumbar pads/pillows Arm rests Glare Eye strain Footrests Wrists pads Keyboard trays Laptops

32. ERGO REMINDERS

33. Practice Wellness at Work and Home ! Exercise Nutrition Relaxation Body Mind Spirit

34. Ergonomic Products There are a variety of ergonomic products available on the market, including: Keyboards Wrist rests Mouse pads Chairs Adjustable desks Glare screens

35. Other Equipments Head sets Recommended when on the phone for extended periods of time, receive frequent calls. Important for people who write or use the computer while talking on the phone.

36. Other Equipments Sit to stand workstations Allows for macro changes in posture Minimizes fatigue or discomfort associated with continuous sitting or standing Can be beneficial for those with back pain

37. Application of Ergonomics for Safety and Health Application of ergonomics can solve the problems of stress and strain due to work load, high or low temperature, more or low illumination or glare, noise, vibration, radiation, awkward work positions and orthopaedic problems due to them. The field of application is very wide which includes following as some of the areas. Hand tools. Design of Controls. Design of work. Design of information displays. Man/machine information exchange. Limitations of the sense organs . Age, fatigue, vigilance and accidents. Problems of body size and posture. Effects of climate . Anatomy of function. Physiologic measurements. Application of skeletal-muscular forces (e.g. manual handling and lifting.)

38. Ergonomics is also utilized at design stage where it is called. "System Ergonomics" in contrast to "Classical Ergonomics" which is applied to solve the ergonomic problems as and when they occur once a design has been put in use. System ergonomics is a higher level of practice involving a knowledge of .. Different tasks the machines can perform. The relative cost. A variety of tasks and satisfactory work for personnel

39. In designing work, ergonomics can be applied for the design of systems, work places, environments, interfaces and work situations. Some examples are as under: Sr. No. Type of Examples 1 System Man-machine relationship, procedure 2 Workplace Posture, seat and control design, bench position, displays 3 Environmental Required lighting, heating, ventilation, noise, vibration etc. 4 Interface Exchange of information between man and machine/environment, scales, pointers, letters, numbers, their size, shapes, position, forces etc. 5 Work Situation Hours of work, rest pauses, shift work, interpersonal and organizational aspect of work.

40. Following are some of the examples of application of ergonomics (human engineering) to matters of health and safety : Stresses of excessive heat, light, humidity, noise, vibration etc., their safe limits, type of worker e.g. age, sex, fitness etc., and task to be performed - all should be considered and suitable environmental conditions should be designed to fit appropriately to the worker and his task. Surrounding space, seat design, bench design and positioning of displays, controls, materials, tools, equipment, instruments etc. should fit the human body so that he can work without excessive effort within the range of healthy posture. Interface display and control design should consider effective information between the man and the machine or environment in type and size of numbers, letters, pointers, shapes and discrimination, identification etc.

41. Good lighting on staircases and in corridors prevents accidents and reduces product damage. Light up corridors, staircases, ramps and other areas where people may walk or work. Use light colours for walls and ceilings when more light is needed. Light colours for walls and ceilings improve lighting conditions and the workplace atmosphere.

42. Use of an absorbent shield to block heat radiation. local exhaust systems to remove dust and gases at source before they reach the worker.

43. Place frequently used materials, tools and controls within easy reach.

44. Working hours, rest pauses, shift work, interpersonal and management problems should be studied and resolved to maintain health and safety of work people. It should be aimed to do work with a minimal use of energy and materials and without waste resulting from mistakes. Human errors should be minimized for safety and health. Design and production of automotive, vehicles, communication equipment, farm machinery, military service, aerospace systems, computers and electronic equipment can be made safe and most suitable to the operators. Highway signs, typewriters, data processing systems, machine tools, kitchen stoves, street and highway design, rapid-transit facilities, health facilities, housing , pollution control, education, law enforcement, postal service, airports etc. are newer areas where ergonomic design can give good results and reduce accidents.

45. Deciding allocation of functions between men and machines. Functions of perceiving, responding to emergency situations, some typical judgments etc. are better done by men than by machines. Functions of heavy lifting, computing, auto regulation, handling large amount of information etc. are better performed by machines than by men. These are to be considered at an early stage of design. Task analysis to decide selection standards, workloads, training requirement, manpower requirement, equipment design can be carried out. Factors of control design, e.g. control display ratio, safeguards against accidental activation, control coding etc. are part of ergonomic design. Workplace dimensions, location of controls and displays, seat and penal design, the design of doors and access for easy entry and exit and protective devices for emergency situations need to be well designed.

46. Mark escape routes and keep them clear of obstacles.

47. For good maintenance easy and simple maintenance manuals, tools and test equipment, better location of units for easy access, fault- finding techniques etc. are to be designed properly. Allowance for local weather conditions, ventilation in cramped premises, providing stool to put container to avoid frequent bending, elementary checklists are ergonomic aspects. Manual material handling has a large scope of ergonomic considerations. Process flow, job design, layout, selection of equipment, machine, tools, space requirement, control design, visibility, colour and signs, allowing push and pull instead of lift and lower, avoiding severe bending, lifting and lowering between knuckle(hip) height and shoulder height, avoiding excessive weight, avoiding sharp edges, corners, pinch points, training for safe lifting practice and lifting rules (dos and don'ts), personnel selection etc. must be well considered. Wrong design of hand tools can create bending of wrist, pressure points between the hand and the handle, sustained exertions, vibrations etc. Therefore hand tools should be designed in such a way that they eliminate or minimize these hazards. Oblique angle of the handle, proper shape, diameter and length of the handle, rounding off all edges and sharp corners, minimizing noise and vibration etc. are useful criteria.

48. 16. Office, other work places and workstation design call for specific criteria. Ideal, practical and detail planning, work process, equipment, workplace layout, final enclosure, mock-up, trial and redesign, clearance for the operator's body, sufficient head room, visual field, auditory information, standing or sitting position (both have advantages and disadvantages), work space dimensions, body position to operate computer, healthy work postures, eye height, elbow height, knee height, seat design to reduce physiological and biomechanical stresses by providing wide range of adjustments and postures to suit the individual (seat height adjustable between 15 to 20 inch, deep 15 to 17 inch, wide 18 inch or more and backrest to support back and neck and opportunity to change body posture frequently) etc. are some important criteria. Recommended dimensions for most seated tasks

49. Controls - continuous or detent - should be designed by considering consistency of movement, control actuation force, multidimensional operation, operator-control orientation, control-effect relationship, time lag, arrangement and grouping, coding and prevention of accidental activation etc. Light signals provide useful safety and functional indications. Displays provide necessary information to the operator. They may be visual (lights, scales, counters), auditory (bells, horns), tactile (shaped knobs, Braille writing) or audio-visual (buzzer with light, TV display). Selection depends on type of information to be provided and to whom provided . Labelling permits rapid and accurate performance of controls, displays and other items that should be identified, read, manipulated or located. Label characteristics are accuracy, time of response or recognition, distance, illumination, nature of function and consistency. Their visibility, legibility, location, orientation, abbreviation, shortness and standardization are necessary. Legal notices must be displayed. From. above varieties of examples it is evident that ergonomics has wide applicability to many functions in addition to health and safety.

50. Manual tasks risk factors Research has identified specific risk factors related to hazardous manual tasks that play a significant role in the development and onset of musculoskeletal injuries. By preventing or minimising the exposure to these risk factors, the risk of injury can be reduced. The five manual tasks risk factors are: forceful exertions awkward and static postures vibration repetition duration.

51. Forceful exertions Forceful exertions place high loads on muscles, tendons, ligaments, joints and discs. Muscles fatigue with increased exertion and need more time to recover. If soft tissue does not have time to recover, injury is likely to develop over a period of time. If the exertions are forceful enough, body tissues may be damaged immediately. Forceful exertions include forces exerted by muscles, such as when lifting items, carrying loads, holding one position for a period of time, or using a forceful grip. Exposure to forces also occurs as a result of external forces applied to the body, such as the weight of a load being carried, or when jumping down when getting out of mobile plant. The level of muscular effort needed to do a job may be increased by factors such as: awkward or fixed working postures heavy, bulky, unstable or difficult to grip loads fast, sudden or jerky movements

52. working with a grip that does not allow a large area of the hand to contact the load using vibrating tools that need more effort to grip wearing gloves using poorly designed hand tools the way loads are handled (e.g. physically lifting, pushing, pulling or carrying) poorly maintained tools and equipment.

53. Lifting heavy pieces of concrete Placing timber ramp Examples of tasks requiring forceful exertions

54. Awkward or static postures The term awkward postures refers to any posture where the body parts are away from their comfortable, neutral position (e.g. a bent back, a bent wrist or arms raised above the head). Awkward postures result in stretching or shortening of the connective and nervous tissues. As a result, the functional capacity of muscles can be reduced and the tissues are at greater risk of injury. Awkward postures are not always harmful. It is only when they are repeated frequently or performed for a long time. The term fixed or static postures refers to postures where part of or the whole body is kept in the same position for a long period of time (e.g. standing in one position with no movement). Static postures quickly fatigue muscles because blood flow is more restricted due to the lack of muscle movement. This can lead to blood pooling and a lack of blood supply to some areas of the body and increase the risk of injury.

55. Awkward or static postures can be caused by: the work area design (e.g. working at ground level or overhead) handling bulky, heavy or large loads using poorly designed hand tools pushing, pulling, or carrying loads which block the worker’s view performing tasks which require loads or body parts to be supported or held for some time.

56. Examples of tasks involving awkward or static postures Preparing foundations S t eel fixing Concrete screeding Laying reinforcing steel

57. Vibration Civil construction workers can be exposed to vibration from a variety of sources including operating trucks, excavators and bobcats, vibrating needles, compacting plates, jackhammers and other pneumatic tools. Sanders Grinders Chipp e r s Routers Drills Saws The two main types of vibration that can lead to musculoskeletal injuries are: whole body vibration hand/arm vibration

58. Whole body vibration Exposure to whole body vibration occurs when the body or parts of the body come in contact with a vibrating surface, such as the seat, pedal or floor of heavy vehicles or machinery. Whole body vibration exposure has been shown to be a strong contributor to lower back injuries. Examples of exposure to whole body vibration Operating backhoe Operating skid-steer loader

59. Hand/arm vibration wh e n working w i t h air-operated, Exposure to hand/arm vibration occurs pneumatic, electric, or petrol powered tools. Exposure to hand/arm vibration primarily damages vascular and nerve tissue, typically of the hand and fingers. Prolonged exposure can eventually result in a disease known as Raynaud’s syndrome or Vibration White Finger. When the body or limbs are exposed to vibration, the force of this movement is absorbed by the body’s skin and the musculoskeletal system. Intermittent exposure to vibration may allow sufficient time for the soft tissues to recover between periods of exposure. However, long duration or frequent vibration exposure will significantly increase the risk of musculoskeletal injury.

60. Examples of exposure to hand/arm vibration Operating petrol-powered jack hammer Operating plate compactors

61. Repetition Repetition means making the same type of movements over and over (e.g. laying bricks). The work cycle is the time taken to perform the task once without interruption (e.g. the time to lay one brick). Tasks involving short cycle times (less than 30 seconds) and performed for more than one hour, are considered to be a risk because the same muscles and other soft tissues are being used continuously. This contributes to their fatigue and risk of injury. Tasks involving longer cycle times and shorter task duration will have a lower risk of injury. Laying paving blocks Shovelling road base

62. Duration Duration is the time taken to perform the task once, or perform the task repeatedly without a break. The longer a task takes, the greater the cumulative load on the musculoskeletal tissues. If the same musculoskeletal tissues are loaded without a break for extended periods, then the mechanical properties of those tissues begin to change, decreasing their functional capacity and increasing the likelihood of injury. Duration may be considered as a significant risk factor when a task is performed continuously for one hour or longer. Screeding concrete Laying reinforcing steel

63. What Are MSDs? MSDs are injuries and illnesses of the soft tissue and nervous system that affect your body’s: Muscles Nerves Tendons Ligaments Joints S p i n al d is c s

64. Musculoskeletal Disorders: Anatomy of an Injury The average person working at a keyboard can perform 50,000 to 200,000 keystrokes a day. Small repetitive movements can disturb the delicate balance of muscles, tendons, and ligaments in the hand and cause cumulative trauma disorders (CTDs), also known as repetitive strain injuries (RSI’s) or musculoskeletal disorder (MSD's). These conditions occur over time and are also referred to as overuse articles. The use of proper keyboard and pointing device techniques, rest breaks, and a properly set up workstation, can significantly reduce the risk of developing an overuse injury

65. What causes upper extremity nerve injuries? The nerves that supply the arm leave the spinal cord in a complicated network of nerve fibers, roots and bundles called the brachial plexus. These nerves course down the side of the neck to form the median, radial and ulnar nerves that travel down the arm and innervate the muscles and provide sensation. Motor nerves send signals to muscles telling them to contract; sensory nerves allow you to feel sensation where they supply the skin. If these nerves are compromised in any way, loss of strength and sensory changes can result. Nerves can be compromised through repetitive movements. Repeated motions can result in compression or "entrapment "of nerves. Compression can be caused by tight muscles, inflammation of surrounding tissues, or misalignment of the nerve.

66. n e r v e When a s e ns a t i ons some w h e r e b e t w e en the p o i n t i s c omp r e s sed , y o u f e e l t he of compression and your fingertips. Ulnar, radial or median nerve compression can occur anywhere along the path they travel through, from the neck to the hand. Shoulder pain can be referred from a nerve pinched in the neck. Pain in the forearm, wrist, or fingers can originate from compression at the neck, elbow or wrist level. That is why when you have pain in your elbow, wrist or hand, you should start rlooking for the cause at the neck and move down the arm. Nerves can also be compressed in more than one place. This is very common with computer users who have muscle tightness or tension in several places. This phenomenon is called a double crush injury and can be very difficult to diagnose.

67. Common MSDs Carpal tunnel syndrome Tendinitis Trigger finger Raynaud’s phenomenon

68. Signs of MSDs Less strength for gripping Less range of motion Loss of muscle function Inability to do everyday tasks

69. Common Symptoms of MSDs Painful joints such as wrists, shoulders, forearms, knees Pain, tingling, numbness in hands or feet Shooting pain in arms or legs Swelling, inflammation, burning sensation Fingers or toes turning white Back or neck pain or stiffness

70. Report Signs or Symptoms of MSDs Permanent disability may result if not reported early Report signs or symptoms of MSDs to your supervisor or human resources representative Report MSD hazards

71. Management Leadership and Employee Participation MSD reporting and response system Designate persons with authority and resources to run the program Policies do not discourage employee participation or reporting of MSDs Employees participate in development, implementation, and evaluation of ergonomics program

72. Safe Use of Muscle System & Lever System in Load Carrying. Muscle system consists of about 200 skeletal muscles in the body. They are in the form of bundles of muscles and wrapped on each other. They are connected with tissue carrying nerves and blood vessels inside. The tissues combine to form tendons which connect the ends of the muscle to bones. The sheaths of the connective tissues provide mechanical properties to the muscle. A muscle has only action to contract. Elongation is by external force. Filaments of muscle sliding along each other provide automatic contraction after elongation. Signal to contract comes from brain by the neuromuscular system. Signals coming to motor units of the muscle can be observed by electromyogram (EMG).

73. Some safety measures are as under: While handling material, force exerted by hands should be transmitted through the whole body parts including feet to the floor. In this chain of forces, weak link is spinal column, particularly at the low back. This limits the capability of a person to work. Therefore task should not be too heavy. Tasks, equipment and system should be designed to provide ease and efficiency of manual handling. L a y ou t o f m a t er i al t r ans f er and f ac i l i t i es s h oul d be c o n v e n i e n t and comfortable to the people . Job design should be safe, efficient and agreeable for the worker. Selection of tools, machines, equipment should be proper. Sufficient space for movement, visibility, lighting, colour coding and control design are important. Select persons capable of performing the job. The job should be designed to fit the worker. Give training for safe lifting practices .

74. Physiological Problems with Load Carrying (Injuries, Fatigue etc.) & their Solutions . Problems with load carrying activity are as under: Limits of human capability of movement in body joints and in spinal column, body size, sex, age, energy capacity (heart rate). etc. Therefore load carrying capacity varies with age, sex and overall strength of a person . Physical Fatigue due to overexertion that causes temporary decrease in physical performance. Reasons of fatigue are workload i.e. static and dynamic work, lack of rest or sleep, illness, pain, poor food intake etc Mental fatigue due to psychological factors like monotony, conflict, worry, de-motivation etc. Work and rest cycle depending on intensity of work. Heavy work requires more rest periods at short intervals . Faulty layout of material transfer requiring more time and more effort. Wrong design of job. Where machine is required, job is given for manual working or carrying. Excessive weight, odd size, sharp edges, hot material, oily or slippery surface, invisibility etc. are some of such factors. Non-provision of sufficient space for movement, necessary hand tools, proper controls, signs (e.g. arrow) for lifting or placing etc .

75. Solution to above problems require Decision whether man is required or machine is required for a particular job Weight should be within limit i.e. not excessive for a person to be employed Proper design of job itself and of facilities, tools and equipment etc. Sufficient space for movement, illumination, necessary rest intervals, proper clothing, drinking and food arrangement etc. Proper selection of persons based on their size, sex, age, strength etc so that work matches with the people. Break down whole material movement process from receiving to distribution into different functions or segments and in each such division plan the actives of material handling in detail and separate out jobs for machines and men. Then allocate accordingly . Plan movement of material in horizontal plane. Arrange push or pull instead of lift or lower. Avoid severe bending movement. Delivery of material at workplace should be at hip height instead on ground floor. Lifting and lowering height should be between hip and shoulder height. This will cause less injury Handling should occur close to and in front of the body. Material should be' light, compact and easy to grasp. It should not have sharp edges, corners or pinch points. Containers or bins should be of sufficient size. Material can be put or removed easily

76. Ergonomic Design of Hand Tools Ergonomic design of hand tools takes into consideration that they should: Effectively perform the intended function. Be properly proportioned to the dimensions of the user. Be appropriate to the strength and endurance of the user. Minimise user's fatigue. It should be comfortable to him. Provide sensory feedback. Som e biomec h ani c al f a c t o r s t o be c on s i d e r e d i n t oo l d e s i gn a r e g r as p , handedness (left or right, single or double), hand strength, sex and clothing. Criteria affecting handle design are its shape diameter, length, angulations and texture. Specific criteria are - diameter, shape, weight, section, length angulations of and placement of handle for hammer. Screw drivers, pliers, saws and power tools are important for ergonomic design.

77. Design of Tools in relation to Body Postures Ergonomic design of hand tools is necessary so that tools and their handles properly fit to the hand grip, avoid unnecessary bend, movement or pressure of fingers and wrist, provides smooth surface and shape for safe handling, insulation for electrical tools and requires less force while working. Some such design criteria are as under.. 1. Tools should have bend and should be b e s t fi t t i n g t o the s h ap e , si z e and functions of the hand. 2 . Th e r e b e t w e e n a r e di f f e r e n t i n t e r ac t ions the ha nd and the ha n dl e , control or support viz. finger touch, palm touch, hook grip, tip grip, pliers grip, side grip, writing grip, disc grip, finger palm enclosure, power grasp etc. Handle, control, knob, lever or support should be properly designed for such couplings between hand and handle, control etc.

78. Cross section and longitudinal shape of the handle must be proper. Circular cross section is mostly preferred. Handle size should accommodate the palm for sufficient grip Pressure points and rough surface of handle should be avoided Round off sharp edges or corners on the handles for safe holding. Avoid cooling or heating the hand by appropriate covering (insulation) on handle. Hand tools should have minimum vibration, Gloves should be used if useful.

79. Safety while using Power tools. Working with power tools can be dangerous. Provide safe power tools and make sure that safety guards are used. For this reason modern chainsaws, for example, have several safety devices. Without the following safety devices, chainsaws should not be used: separate handles for both hands when wearing gloves an on/off switch (reachable with the right hand on the throttle) a throttle control lock-out (prevents the chainsaw from being started unexpectedly) a rear handle guard (for protection of the right hand) an anti-vibration system, consisting of rubber shock absorbers between the engine block and handles (prevents vibration diseases of the hands) a chain brake (activated manually by the front handle guard or by means of a non-manual mechanism in the case of kick-back) a chain catcher (catches the saw chain if it breaks) a spiked bumper (allows the weight of the saw to rest securely) a front handle guard (for protection of the left hand from the chain) a chain guard (for avoiding injuries during transport of the chainsaw)

80. Use hanging tools for operations repeated in the same place. Hanging tools can be grasped easily near the point of operation.You can save the time needed to put the tool down and pick it up again.The time grasping the tool is shorter and the worker’s fatigue is less.

81. Use vices and clamps to hold materials or work items Manual operations greatly improve when the materials or work items are firmly fixed. Vices and clamps allow workers to use different sizes and shapes of work pieces steadily during the work. The use of vices and clamps allows the workers to use both hands. Vices and clamps also reduce accidents, as they prevent slippage of material, reduce the need for maintaining a bad posture and provide better control over the work item.

82. Safety while using tools - Prevention & Control of Tool Accidents The right tool for the right job: Wrong methods are: To use file instead of pry, wrench instead of hammer, pliers instead of wrench etc. This may cause accident. Therefore it should be avoided. Tools in good condition : Examples of poor condition are : Hammers with loose handles, screw drivers and cutting tools with broken points or broken handles, wrenches with cracked or worn jaws, dull saws, and flexible electric cables with splint insulation, broken plugs, unearthed ground wire etc. Such conditions should be removed. Tools used in the right way: Wrong ways are: Screw drivers applied to job (e.g. to open a lid, to remove bearing), knives pulled toward the body and failure to ground electrical equipment. Tools should be used in right way. . Tools kept in a safe place and safe way: Unsafe practices are: Tools kept overhead so as to fall; chisels and other sharp tools kept in pocket or left in tool boxes with cutting edges exposed. They should be kept in a proper way. Good housekeeping for orderly layout and cleanliness: Haphazard lying of tools anywhere, leaving tools at the workplace after completion of the job, slippery surface not cleaned, tools kept in aisles or walkways etc. are common causes of tool accidents. Tools should be kept orderly.

83. Training for usage - The supervisors and workers should be trained: To wear safety goggles, face shield, helmet etc.as per requirement. To select the right tools for each job and their right use. To return the tools after use. To guard, inspect, repair and maintain tools in safe condition. To use the proper storage facilities in the tool room and on the work place. To put the tools in such a way that they can be readily available. To scrap and replace the tools when worn. To check. out-tools at cribs. To store in safe condition when not in use.

84. Introduction to Anthropometry. Anthropometry and biomechanics are branches of ergonomics dealing with physical dimensions and properties of the human body. Anthropometry means measuring the human body. Height, breadth, depth and various distances of the body parts are measured. Curvatures and circumferences are also measured. Measurements are taken in stand-erect or seated position. Body dimensions are measured by anthropometers, calipers, taps and a scale. Such dimensions are useful in designing work spaces, tools, equipment, seating arrangement, vehicles and workstations so that they can best fit to the users.

85. Concept of Percentiles Percentile indicates which percentage of a known population is fitted by a design range. Suppose work seat height is to be designed most convenient to majority of men and women, its range should fit to the women in 5 th percentile to the man in is 95 th percentile. This means much deviation will not be required in this range of seat height (say lowest 35.5 cm to its highest setting at 48.8 em). Then addition of 2 cm for heal height may be required. 50 th percentile corresponds to a single fixed seat height of 41 cm for a mixed male- female population, but, this will be too high for about 50 of the people and too low for the rest. Thus designing for the. average fits nobody 5 th , 50 th and 95 th percentiles measurements for human height, depth, breadth, head, hand and foot dimensions are available for ergonomic design purpose.

86. Health problems related to wrong postures, back pain etc Sitting or standing in the same posture for a long time exert muscle tension and spinal compression. Therefore this should be avoided by providing rest periods, physical activities or exercises. Computer operators keep the head in a fixed position for a long time and therefore suffer pain and tension in the neck area. Intensity, frequency and long h o u r s of m u sc l e c on t r act io n s c a u s e se v e r e d is c o m f or t , pain a n d o t h er musculoskeletal disorders that last for long periods. Lumber spine suffers more force while sitting on a stool without backrest than in standing at ease. Leaning back over the backrest and arms hanging down reduces compression force. Straight upright backrests do not support the body and high disk forces may occur. When it is declined back and upper body weight is rested on backrest, internal forces are also declined. Relaxed leaning on a declined backrest is the least stressful sitting posture.

87. Adjust the working height for each worker at elbow level or slightly below it. The correct height of places where work is done with the hands facilitates efficient work and reduces fatigue. Most work operations are best performed around elbow level. If the worksurface is too high, the neck and shoulders become stiff and painful as arms must be held high. This happens in both standing and sitting positions. If the worksurface is too low, low back pain easily develops as the work has to be done with the body bent forward. This is serious in a standing position. In a sitting position, too low a working height causes both shoulder and back discomfort in the long run. Most work operations are best performed around elbow level.

88. Recommended dimensions for most seated tasks.

89. Recommended dimensions for standing work.

90. Make sure that the workplace accommodates the needs of smaller workers. Use a foot platform for smaller workers to ensure an appropriate work height at around elbow level. A v o i d a s i t u a t i o n wh e r e controls or machinery are difficult to reach.

91. Make sure that the workplace accommodates the needs of taller workers Ensure there is enough space for larger workers in aisles and at workstations. Remember to provide sufficient knee and leg clearance

92. Provide a stable multi-purpose worksurface at each workstation.

93. Make sure that workers can stand naturally, with weight on both feet, and perform work close to and in front of the body. Fatigue of workers and the risk of neck, shoulder, arm and back disorders are reduced when the work is done avoiding unnatural postures.

94. Allow workers to alternate standing and sitting at work as much as possible. Alternating standing and sitting is much better than keeping either posture for a long period of time. It is less stressful, reduces fatigue and improves morale

95. Provide sitting workers with good adjustable chairs with a backrest Seated work seems comfortable compared with other forms of work. However, sitting for long hours is also tiring.Good chairs reduce fatigue, improve work efficiency and increase job satisfaction

96. Use height-adjusted computer workstations, and arrange related computer peripherals within easy reach Adjusting the height of the workstation to preferred positions of displays and controls can reduce visual, neck, shoulder and back strains. If the display screen, keyboard and chair height can be easily adjusted, both large and small workers can use the same workstation comfortably. The prolonged use of a laptop computer on a standard desk can be straining to the neck, hands, wrists and shoulders. This is because laptops have smaller and lower displays, smaller keyboards and track pads. Adjustable workstations can avoid these strains. Computer peripherals that are well arranged within the reach of the worker can reduce unnecessary overreaching motions and secure adequate lighting while reducing screen glare. Well-adjusted computer workstations can help workers organize their work at their own pace. Workers can thus insert micro-pauses that help them recover from fatigue and work.

97. Each visual display unit user must be able to find his or her best work positions. Arrange the computer workstation so that work is done comfortably. Train the operator about appropriate work postures and spatial arrangements

98. Ergonomic Office Furniture and Utility Tools Workstation consists of furniture, equipment, work material and overall environment. Persons do job there. Work posture includes movement of body parts and work activities include visual, auditory, vocal and motor types. Their combined effect is performance output and persons' well being. Work space design, good lighting and ventilation, attractive and comfortable work situation are basic requirement. Office furniture and utility tools like controls, displays, switches, trays, bins, office equipments and instruments also play an important role. General system components include computers, keyboards, tables, chairs and cupboards. But operator is the most important component in this system. because work output depends on him and he utilizes other components of the system. He should be most comfortable. His body dimensions are useful in designing workstation dimensions as under -

99. D i me n sion s s h oul d be sl i gh t l y ad j u s t able ac c o r d in g t o in d i v i d ual ' s requirement. Visual tasks - monitor, key board, papers, books etc. - should be at eye height. Keyboard, mouse, notepad, pen and hand controls should be convenient to elbow height and forearm length. Leg room height depends on knee height, and thigh thickness and its depth depend on foot length. Thigh width and lower leg length (Popliteal height) decide the width and height of the seat pan. Functional reach decides height of shelves and other furniture. Furniture should provide user freedom to extend legs or hands, to lean foreword or backward, to rotate left or right and to take any posture . Ergonomic chairs with large backrest are most comfortable as they provide support to back and neck. Seat height must be fully adjustable. (height 35 to 50 cm, depth 35 to 45 cm and width 45 em ), Seat surface should not generate any pressure to the seated person. Armrests are useful in reducing compression load on the spinal column. Visual targets should riot be spaced apart in direction or distance from the eye. They should be easily viewable in the front. All components of workstation should fit each other and each should fit the operators. Flexibility for individual requirement is also necessary .

100. Location & Sequence of Operation Controls are mostly hand or foot operated. They transmit inputs to machine, vehicle or equipment. They are selected on .basis of their functional utility and located in easy reach so that operator's body parts are not overstressed. Controls are of 'continuous' type (e.g. crank, knob wheel etc) or 'detent' type (e.g. key lock or switch, bar knob, thumbwheel & different switches) where step wise operation is required. Controls having sequential relations should be arranged in functional groups with their associated displays and in operational sequence. If sequential operation follows fixed pattern like car gear handle, they should be arranged to facilitate operation i.e. top to bottom or left to right. Sufficient spacings required for movement. Controls should be located as per operator's requirement i.e. easy operation. Time lag between control input and system response should be minimum and consistent with safe and efficient operation.

101. Knobs are provided where little force is required and when fine adjustment is necessary. Hand wheels are used for two hand control. Then knurling (corrugation) should be provided for good grasping. When levers are used for fine or frequent adjustment (e.g. car gear lever) limb support are useful. e.g. elbow support for large hand movement, forearm support for small movement and wrist support for finger movement. When several levers are located side by side, the lever handles should be coded. Levers should be labeled for their direction of motion and function. For joystick controls (three dimensional steering), elastic resistance is added for smooth displacement.

102. Natural Expectation of Control Movement Control movement should match with natural expectation e.g. foreword motion for front driving, backward motion for reversed driving, clockwise motion for right direction and anticlockwise for left direction, forward' motion for boom descend and vice- versa. In electrical switches, downward indicates 'on' and upward indicates 'off' position. This is natural expectation. In key lock switches (e.g. car ignition switch), key's vertical position indicates 'off' position, turning clockwise indicates 'start' position and key should not come out without turning the switch i.e. without stopping the vehicle or machine. The 'on' and 'off' positions should be labeled.

103. Preventing Accidental Activation Controls should be so designed and located that they will not move or change their position accidentally. They should not come out accidentally or by slight touch from 'off'· to 'on' position and start the vehicle or machine [Section 24(3) of the factories Act]. Such inadvertent operation can cause accident to person, machine or system. To prevent such accidental activation, following measures are useful - Cover or guard the control. Provide interlock so that extra movement is required to change the position. Provide resistance by spring action or viscous friction so that extra effort is required for actuation. Provide rotary action for operation. Provide recess, slot, shield etc to contain controls within it and finger is' required to insert inside. e.g. push button or switch in recess or guard on foot pedal of a power press. Provide 'on' and 'off' button separately and with different colour. Provide' Dead man control' which will keep the system working till the control is pressed and will stop the system when the control is released, e.g. petrol nozzle trigger (knob) or drill machine push button.

104. Foot controls Foot controls have specific use and where powerful braking force is required or when leg is only convenient limb, viz. brake pedal or acceleration control lever in car or brake pedal for power press, press brake, metal shear and other machines. Limit the number of foot pedals and, if used, make them easy to operate

105. Displays and Light Signals These are useful to provide necessary information to operator. They may be dial gauges, pointers, digital, audio, visual, analog etc. Bell, horn and warning notices are' also displays which give information. Colored signals have some meaning as under - Red - Stop position. Flashing Red - Emergency condition. 3. Green - 'On' position or 'yes' indication to proceed. 4. Yellow - Wait, delay or be in readiness position. It also indicates caution or rechecking. 5. White - No right or no wrong, transitory condition.

106. Locate the most important displays and signals at a viewing angle of about 20–50 degrees below the horizontal line from the eyes of the operator standing or sitting naturally Make displays and signals easy to distinguish from each other and easy to read Displays and signals carry information about work, and they should be easy to identify. It is important to consider the location of displays and signals, and also to make them easily distinguishable from each other. Good visibility of pointer positions, characters and numbers on displays or signals also ensures high quality work. Incorrect reading of displays or signals is sometimes critical, as this may lead to operation failures and accidents.

107. Displays should have clear meaning. They should be easy to understand and visible, properly illuminated, also visible when power fails, coded and labeled according to function. Numerical display indicates time, temperature, pressure, flow, humidity, pH, speed etc. Moving pointer on a fixed scale have many shapes - circular, curved, horizontal straight or vertical straight. Numbers or figures should not be obstructed by pointer. Displays should be located in viewing area and perpendicular to the line of sight. Labels should be provided where extra information is necessary.

108. Use markings or colours on displays to help workers understand what to do. A display instrument should convey the required information as simply and unmistakably as possible.

109. Use symbols only if they are easily understood by local people. Symbols are sometimes used to identify machines, chemicals, controls and displays. In fact, many international manufacturers of machines prefer to use symbols, because they do not have to translate a label into the local language. But many symbols are difficult to understand, particularly those referring to machine functions that are hard to visualize or imagine. It is often better to use a short message instead.

110. Make labels and signs easy to see, easy to read and easy to understand. Labels and signs must be easy to read, otherwise they will be ignored. People tend to read labels and signs only at a short glance, and therefore often make mistakes in reading them. This may lead to performing the wrong operation and may cause an accident. Labels and signs must be large and clear enough to be easily read at a distance. Text must be made easy to understand so that people will know what to do.This is productive because it will save time.

111. Use warning signs that workers understand easily and correctly Warning signs are used to warn against hazards. They often carry a complex message, because it is necessary to convey what the hazards are and what the person should do to avoid them. Make sure that warning signs are easily understood by workers. Lengthy warning signs are in fact not read by all workers. It is important to choose compact but easy-to understand messages.

112. Five Key Points to Remember Ergonomics can help you on your job WMSDs can happen in jobs with risk factors Risk factors can be reduced and WMSDs prevented Reporting signs and symptoms early is important You can help your company put ergonomics changes into place.

113. Summary You Can Reduce Risk Greatly Improve body posture and keep a safe body position avoid awkward positions use tools and equipment correctly Rearrange work area- control your environment, use the right equipment in the right position, keep work within reach Change work habits practice and use correct procedures, avoid repetition and long duration of a single task take frequent breaks Apply ergonomic principals at home, too 

114. Takeaways There is an old proverb that says: “Too much or too little of anything is detrimental ”. Keeping our pace at the workplace, or at home doing the things we love most over our computers is beneficial to our general health . It is never wrong to halt for a bit, and walk away from too much work, and find some relaxed time with your self.

115. Thank You..!!