ERGONOMY Dr Majid Golabadi

Terminology ERGO = WORK NOMOUS = LAW

A science that focuses on human capabilities and limitations in the design of work tasks, workstations, tools and equipment. Ergonomics

People Are Different

People Have Physical Limitations

People Have Emotional Limitations

NIOSH: The science of fitting workplace conditions and job demands to the capabilities of the working population “fitting the job to the worker”

A Model Framework for Assessment of Medical Fitness for Work Fitness for Work

Ergonomics OHS Anatomy Management Engineering Environmental Science Toxicology Computer Science Psycology Design BiomecanicsPhisiology Ergonomics a Multidisciplinary Science

Ergonomy classification: Micro Ergonomy. Macro Ergonomy.

The function of specialists in ergonomics is to redesign or improve the workplace, workstations, tools, equipment, procedures of workers and work organization so as to limit fatigue, discomfort, and injuries

Payback period for ergonomic interventions 1 Year

Job redesign outcome 1- Reducing risk factors for common Musculoskeletal Disorders 2- Reduction in Acute Injuries

Anthropometry: Definition: Anthropometry is the measure of man (anthro = man, pometry =measure). The study of anthropometry is the study of human body measurements to assist in understanding human physical variations and aid in anthropological classification.

Ergonomic Risk Factors

The physical stressors or risk factors that are associated with Work related Musculoskeletal Disorders are: Sustained awkward postures Static/Sustained Posture The application of sustained or high forces Rapid, repeated motions Contact stress Vibration Cold environment

Awkward Posture Deviations from neutral positions. The greater the degree of deviation, the higher the risk.

Natural Posture(Standard posture) امتداد خط مستقيم فرضي از گوش تا مچ پا كمترين فشار بيومكانيكي و تنش به بافت ‌ هاي دستگاه اسكلتي ـ عضلاني ميانه دامنه حركتي ايمن ‌ ترين وضعيت بدني حداكثر راندمان كاري

THE HEAD AND NECK NEUTRALFLEXIONEXTENSION

THE TORSO AND BACK NEUTRAL FLEXED TORSO AND BACK EXTENDED TORSO AND BACK

THE ELBOW AND SHOULDER NEUTRALELBOW FLEXIONELBOW EXTENSION ’<90’>110’

THE HAND AND WRIST NEUTRAL EXTENSIONFLEXION RADIAL DEVIATION ULNAR DEVIATION

Static/Sustained Posture When a worker must maintain an unsupported position for an extended period of time.

End Range Posture Refers to moving a joint as far as it will go or close to its maximum. Stress is on the muscles, tendons and ligaments as they are stretched to end range.

Improvements

Forceful Exertions

The amount of work the joints, muscles, and tendons must do to perform the task. The higher the force, the more risk of fatigue, loss of strength, and injury to muscles, tendons and joints.

میزان وزن بار همیشه باید کمتر از 23 کیلوگرم باشد

بهترین شرائط بلند کردن بار باید بتوان بار را در نزدیکی بدن نگاه داشت ارتفاع اولیه بار از زمین ، قبل از بلند کردن ، باید حدود 75 سانتیمتر باشد تغییر مکان بار به صورت عمودی نباید از 25 سانتیمتر بیشتر باشد امکان برداشتن بار با هر دو دست باید میسر باشد بار باید دارای جای دست یا دسته باشد بدن هنگام بلند کردن بار باید آزاد باشد در هنگام بلند کردن بار نباید بدن را چرخاند در هر 5 دقیقه نباید بیش از یک مرتبه نسبت به بلند کردن بار اقدام کرد عمل بلند کردن بار نباید بیشتر از یک ساعت طول بکشد و پس از آن حتما باید وقفه ای جهت استراحت یا انجام کارهای سبکتر در نظر گرفته شود

افرادی که بیش از 150 بار عمل بلند کردن بار را در روز انجام میدهند در خطر بالائی از بروز کمر درد قرار دارند بلند کردن بار همراه با خم کردن تنه و چرخاندن تنه شایعترین علت بروز کمر درد میباشد در صورتی که عمل بلند کردن بار خصوصیات زیر را داشته باشد ، صدمات اسکلتی عضلانی و شدت صدمه افزایش می یابد : سنگین بودن بار ، حجیم بودن بار ، روی زمین قرار داشتن بار ، مکرر بودن عمل بلند کردن بار

Repetition Refers to a task or series of motions performed over and over again with very little variation.

Contact Stress An outside force coming in contact with the soft or unprotected part of the employee’s body. The amount of damage is dependent on the sensitivity of the exposed body part.

Vibration

Damage to blood vessels Increased muscle fatigue Damage to spine Vision problems Headaches Insomnia

Vibration Reduce the vibration/modify speed Equipment maintenance Vehicle suspension systems Reduced exposure Rest breaks Adequate padding/absorption system Education

Environmental

Environmental Factors Temperature Noise Lighting Air Quality

Hazard Prevention and Control Design of the Work Station Design of the Work Task Design of the Tools/Equipment

WORKSTATION DESIGN PRINCIPLES Reduce Sustained Awkward Postures Reduce Contact Stress Design Work Based on Anthropometric Data Logically Locate Controls and Displays Proper Design of Chairs Avoid Static Body Positions: Task Variation and Exercises Proper Placement of Monitor & Documents

Design Work Based on Anthropometric Data

Logically Locate Controls and Displays

Proper Design of Chairs

Proper Placement of Monitor & Documents

WrongCorrect