Osh Chapter 4 Workplace Environment And Ergonomics 4p1m3s

CHAPTER 4

WORKPLACE ENVIRONMENT AND ERGONOMICS

OBJECTIVES By the end of this presentation you understand: 4.1 Describe the history of ergonomics 4.2 Understand workstation design principles 4.3 Understand ergonomics risk 4.4 Understand workplace environment 4.5 Appreciate the proper and safe methods of ergonomics in the workplace

4.1 Ergonomics

The history of ergonomics • Brief History – Ergonomics: Study of Work – Human Factors: Study of Decision-making – Human Factors/Ergonomics: Study of whole person, groups • Human Factors and Ergonomics is the study of the interaction between humans and their environment • Human Factors and Ergonomics is the use of that knowledge to design for improved safety, comfort, and productivity • Human Factors and Ergonomics is the process of deg interfaces that permit effective and efficient interaction with the environment such as displays, controls, tools and work areas

MATHEMATICAL

PHYSICAL

BIOLOGICAL

BEHAVIORAL & SOCIAL

SCIENCES

SCIENCES

SCIENCES

SCIENCES

The Evolution of Human Factors/Ergonomics as a Science

HUMANFACTORS/ERGONOMICS APPLICATIONS

Integrating Human Factors/Ergonomics with Systems and Systems Safety

Ergonomics = Human Factors

A world beyond manual handling

Ergonomics = Human Factors ‘How humans interact physically and psychologically within the work environment’

Definition of Ergonomics • OSHA defines ergonomics as: “the science of deg the job to fit the worker, instead of forcing the worker to fit the job.” • The relationship of people to their tools, tasks, and environment • Tools are designed to fit the employee

contd. The way we interact with our environment at work, play and rest. Fitting the way we work to the way our body is built is the key.

Ergonomics is… • Adapting the tasks to fit you. • Maximizing your health and comfort by using your body in efficient ways. • Self-evaluation of the behaviors and postures you use at work and play. • Learning to recognize the signs and symptoms associated with an action that may lead to musculoskeletal disorders.

4.2 Workstation Design Principles

Neutral sitting work position posture • A neutral seated posture imitates the neutral standing posture. • The seated position puts your hip and knee ts at a 90o or slightly greater angle. When in use, your elbow ts should also be at a 90o or slightly greater angle. Wrist ts should maintain as straight a posture as possible.

Neutral standing work position posture • Pretend you have a string tied to the top of your skull. Suspend your entire body from that string. Your back is straight, your ts loose, your shoulders relaxed. This is a neutral standing posture.

Fixing the Job • Use neutral postures to perform tasks. • Adjust the work station to remove the risk factor. E.g., raise or lower the work surface, turn the piece, etc. • Rotate between jobs. E.g., break up long typing sessions with some filing or copying, break up leaf blowing with short raking sessions. • Use mechanical assistance. E.g., use a lift to move heavy parts, use a two wheeled truck to move multiple boxes or one heavy box. • Get help. E.g., use a buddy to help in heavy lifting tasks.

cont. • Use personal protective equipment E.g., anti-vibration gloves when using vibrating hand or yard tools.

• Observe micro-breaks E.g., take a stretch break every hour you spend in continuous typing, writing or telephone use.

cont. • Share your ideas. If you find something that works let your supervisor, co-workers and EH&S know so others may benefit.

• Use the self-help tools available on the web at http://www.ecu.edu/oehs

E.g Computer Workstation

Comfortable does NOT mean Healthful • Neutral posture should be the guide for determining an appropriate fix • Comfort can be misleading… Crossed legs may seem comfortable but restrict blood flow A slouch is definitely not a healthful posture We often equate habit with comfort

4.3 Ergonomic Risk: Musculo-Skeletal Disorders (MSD)

Ambient Environment (Noise, Temperature)

Elements of the Office Environment Workstation Design (Physical)

Work Organization (Job design)

Psychosocial (Job control, etc)

Health Outcomes

PERSON

Job Satisfaction

Productivity/Quality

Model of How the Office Environment Leads To Musculoskeletal Outcomes Physical Demands

Office Technology

Biomechanical Strain

Individual Factors

Detection/ Sensatioin

Labeling/ Attribution

Musculoskeletal Outcomes Symptoms

Work Organization

Psychological Strain

Health Care Utilization

Disability

Source: Amick et al, 1999 as adapted from Suater and Swanson, 1997

Musculo-Skeletal Disorders (MSD) • Illness resulting from cumulative trauma to the muscles, nerves, tendons, ligaments, ts, cartilage, blood vessels or spine discs. • An injury caused by an acute incident e.g., a fall or auto accident, or symptoms of a degenerative disease are not considered a MSD and must be treated differently.

Symptoms of a MSD Subjective indicators of potential concern • Painful ts • Pain, tingling or numbness in hands or feet • Shooting or stabbing pains in arms or legs • Swelling or inflammation • Pain in wrists, shoulders, forearms, knees • Fingers or toes turning white • Back and neck pain • Stiffness or burning sensations

MSD Signs Objective indicators identified by a physician to help diagnose specific problems: • • • • •

Decreased range of motion Deformity Decreased grip strength Loss of muscle function Inability to physically perform normal tasks

Risk Factors associated with MSD

• Repetition • Forceful Exertions • Awkward Posture • Stress • Vibration

Repetition • Doing the same motions over and over again places stress on the muscles and tendons. The severity of risk depends on how often the action is repeated, the speed of the movement, the number of muscles involved and the required force. • E.g., steady computer use for 4 hrs/day; a repeated cycle of motions 2 or more times per minute.

Force • The amount of physical effort required to perform a task or maintain control of equipment or tools. • Force depends upon type of grip, weight of the object, body posture, type of activity, and duration of task. • E.g., Lifting 75 lbs one time or 55lbs more than 10 times per shift or 25 lbs below the knees or above shoulder height. Pinching 2 lbs or for 2 or more total hours per shift.

Awkward Posture • Repeated or prolonged reaching, twisting, bending, kneeling, squatting, working overhead with your hands or arms, or holding fixed positions. • E.g., Working with hands over head, kneeling or squatting for 2 hours/day; working with back, neck or wrist bent for 2 hours/day. • Potential fixes: portable stools, turn or move the work, use frequent mini-breaks, integrate the work with other tasks to avoid prolonged use of the awkward posture.

Stress • Pressing the body (or body part) against a hard or sharp edge can result in placing too much pressure on nerves, tendons and blood vessels. • For example, using the palm of your hand as a hammer regularly or typing while resting your arms or wrists on the hard desk edge.

Vibration • Operating vibrating tools such as sanders, grinders, chippers, routers, drills, saws and yard equipment on a regular basis can lead to nerve damage. • Potential fixes: vibration dampening gloves, job rotation, modified clutching mechanisms.

4.4 Workplace Environment

Safe work environment • Airflow Is there enough airflow around the computer to keep it cool? • Light Is there glare on the screen either permanently due to overhead lighting, or temporarily as the sun moves? • Cables Are they housed so no-one can trip on or damage them • Noise Is the level safe, annoying or distracting?

Hazards of Environment Some of the most common environmental hazards are: • Indoor air quality • Lightning and sightedness • Temperature and humidity conditions • Noise and hearing quality

Indoor air quality The following factor that related to the quality of indoor air: • Heating, air conditioning, and ventilation systems •

air filtration

• Temperature and humidity • Volatile and/or toxic organic compounds and gases in the air • Mineral and/or organic fibers and particles in the air • Molds, bacteria and other biological matter in the air.

Lighting and sightedness • Potential Problems:

Overhead lights

– Visual fatigue • Accommodation/Oc ularmotor fatigue: blurring, shadow images • Headache • Eye soreness/dryness

Task Lamp Walls

Monitor

Windows

Probable causes – Environment: lighting, glare, low humidity – Screen design: flicker rate, contrast, brightness, character or image size – Task requirement: duration on task, task complexity, task frequency, etc. – Personal: lack of proper vision correction

The best way for lighting and sightedness Overhead lights

• Diffuse (indirect) lighting is appropriate for most VDT work

low glare lenses or louvers

• Minimize differences in illumination Walls – Create a uniform visual field, reduce glare Monitor

Task Lamp

Windows Line of sight

Temperature and humidity conditions Temperature High/low

Humidity High/low

Pressure High/low

Vibration & noise

Airborne salts, dust, sand, dirt, etc.

Sunlight, lightning, radiation

Meteorological and micro-meteorological conditions: wind, hail, heavy rain

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High temperature conditions Environmental effect  Summer heat  Heat from engines  Heat from chemical processes and reactions  Body heat  Welding  Friction

E. R. Vaidogas, OSH in Construction

Hazard to worker/workplace  Melting of metals and sealants  Fires and conditions which permit vaporisation  Skin burns  Heat exhaustion, heat prostration  Loss of ability of persons to function  Rapid evaporation of liquids  Reduced reliability of electronic equipment  Loss of lubricant effects  Increased gas pressure

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Low temperature conditions Environmental effect    

Winter cold High altitudes Refrigerated surfaces Cryogenic lines and equipment

Hazard to worker/workplace      

Cold “burns” Frostbite, chilblains Plastics and metals become brittle Lubricants congeal Freezing of liquids Failure of engines and thermal processes

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High humidity conditions Environmental effect  Rain, clouds, fog, dew, snow  Tides and floods  Lakes, rivers, and other natural water sources  Vegetation and animal respiration  Temperature decrease without removal of moisture  Condensation on cold surfaces  Flooding and immersion in water  Naturally high atmospheric humidity  Personnel perspiring in inadequately ventilated enclosure, equipment, or impermeable covering  Presence of humidifying equipment

Hazard to worker/workplace  Loss of visibility due to fog, clouds, or condensation  Possibility or acceleration of corrosion  Short circuits, inadvertent activations, or disruptions of electrical systems by moisture condensation in electrical devices  Surface friction for traction reduced by wet surfaces  Flooding of facilities, shops, vehicles, and equipment  Drowning of personnel  Swelling of water absorbent materials  Warping and sticking of wood doors, drawers, and similar items 43

Low relative humidity Environmental effect  Hot weather with the little moisture  Heat in a closed room in winter  Moisture removed by airconditioning

Hazard to worker/workplace  Drying out and cracking of organic materials  Generating dusty conditions  Increased tendency for creation of static electricity  Easier ignition of accidental fires  Increase in airborne salts, sand, dirt, and fungi

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Heat stress card

E. R. Vaidogas, OSH in Construction

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Noise and hearing quality

4.5 Proper & safe methods of ergonomics in the workplace

GROUP ASSIGNMENT 3

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QUESTION Appreciate and practice the proper and save methods of ergonomics in the workplace including: GROUP 1 & 2 Working position GROUP 3 & 4 Workplace design GROUP 5 & 6 Standing bench GROUP 7 & 8 & 9 Computer arrangement You are required to do by: •Group (3-4 persons) •Writing in Essay format (minimum 3 pages, arial 12,double spacing,justify) •Preparing powerpoint –you will present this in next class •Providing pictures/sound recording or videos etc.

QUESTION