IS 106 INDUSTRIAL HYGIENE AND OCCUPATIONAL HEALTH SBTET AP IS

6.1 INDUSTRIAL HYGIENE

6.1.1 Definition and Control Methods

• Industrial Hygiene is the science of anticipating, recognizing, evaluating, and controlling workplace environmental factors that may cause illness or discomfort among workers.

• Control Methods include:

  • Substitution: Replace hazardous materials/processes with safer alternatives.

  • Changing the Process: Modify operations to reduce exposure (e.g., automation).

  • Isolation: Separate workers from hazards through barriers or enclosures.

  • Wet Methods: Use of water sprays to suppress dust and airborne particles.

  • Local Exhaust Ventilation (LEV): Capture and remove contaminants at the source.

  • Personal Hygiene: Promote cleanliness to prevent ingestion and contamination.

  • Housekeeping and Maintenance: Regular cleaning to prevent dust, oil, and chemical buildup.

  • Waste Disposal: Safe and proper disposal of hazardous waste materials.

  • Special Control Measures: For specific risks like noise, radiation, or confined spaces.

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6.1.2 Chemical Hazards

• Introduction to Chemical Hazards: Many industrial processes involve chemicals that can harm health.

• Dangerous Properties of Chemicals:

  • Toxicity: Poisonous effect on body organs.

  • Corrosiveness: Destroys living tissue (acids, alkalis).

  • Flammability: Likelihood of ignition and combustion.

  • Reactivity: Potential for explosive or hazardous reactions.

• Forms of Chemical Contaminants:

  • Dust: Solid particles (cement, silica).

  • Gases: Oxygen displacement or poisoning (CO, H₂S).

  • Fumes: Fine solid particles from vaporized metals.

  • Mist: Tiny liquid droplets (acid mist, oil mist).

  • Vapor: Gaseous form of liquid (solvents).

  • Smoke and Aerosols: Combustion products or suspended droplets.

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6.1.3 Routes of Entry & Hazard Evaluation

• Routes of Entry:

  • Inhalation (lungs)

  • Absorption (skin contact)

  • Ingestion (swallowing)

  • Injection (through wounds or punctures)

• Recognition: Identify the source and type of hazard.

• Evaluation: Measure concentration or exposure level.

• Control: Apply engineering, administrative, and PPE controls.

• Concept of Dose-Response Relationship:

  • Toxicity depends on the amount of exposure (dose) and time (duration).

• Biochemical Action of Toxic Substances:

  • Toxins may affect the nervous system, liver, kidneys, or lungs.

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6.1.4 Threshold Limit Values & Sampling

• Threshold Limit Value (TLV): Maximum airborne concentration of a substance that most workers can be exposed to without adverse effects.

  • TLV–TWA: Time Weighted Average (8-hour workday).

  • TLV–STEL: Short Term Exposure Limit (15 minutes).

  • TLV–C: Ceiling value not to be exceeded at any time.

• Air Sampling Strategies:

  • Personal Sampling: Measures an individual’s exposure.

  • Area Sampling: Measures contaminants in the workplace environment.

• Personal Exposure Monitoring: Regular monitoring of workers’ exposure levels using direct-reading instruments or sample collection devices.

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6.1.5 Work Environment & Biological Monitoring

• Work Environment Monitoring:

  • Regular checks on air quality, noise, illumination, temperature, and humidity.

  • Use of instruments such as gas detectors, sound level meters, and dust samplers.

• Biological Sampling and Analysis:

  • Testing body fluids (blood, urine) for absorbed chemicals (e.g., lead, mercury).

  • Helps assess actual internal exposure and effectiveness of control measures.

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6.2 PERSONAL PROTECTIVE EQUIPMENT (PPE)

6.2.1 Overview

• Need for PPE: To protect workers when hazards cannot be controlled by engineering or administrative means.

• Selection: Based on risk assessment and applicable standards (e.g., IS, ANSI).

• Supply and Use: Employer must provide suitable PPE and ensure proper use.

• Care and Maintenance: Regular inspection, cleaning, and storage to maintain effectiveness.

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6.2.2 Non-Respiratory Personal Protective Devices

• Head Protection: Helmets and hard hats to protect against falling objects.

• Ear Protection: Earplugs and earmuffs for noise reduction.

• Eye and Face Protection: Goggles, face shields against chemical splashes or radiation.

• Hand Protection: Gloves made of rubber, leather, or cut-resistant material.

• Foot Protection: Safety shoes with toe caps and slip-resistant soles.

• Body Protection: Aprons, overalls, flame-retardant or chemical-resistant clothing.

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6.2.3 Respiratory Protective Devices

• Classification of Hazards:

  • Oxygen Deficiency, Dusts/Fumes, Toxic Gases/Vapors.

• Classification of Respiratory Devices:

  • Air-Purifying Respirators (APR): Filters contaminated air (cartridges, masks).

  • Air-Supplied Respirators: Provides clean air from an external source.

  • Self-Contained Breathing Apparatus (SCBA): Independent air supply for confined or toxic areas.

• Selection: Based on type, concentration, and duration of exposure.

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6.2.4 Training and Maintenance of Breathing Apparatus

• Training:

  • Workers must be trained in proper fitting, wearing, and emergency use.

  • Regular practice in donning SCBA in limited visibility or confined space.

• Maintenance:

  • Regular inspection, cleaning, refilling of air cylinders.

  • Keep detailed maintenance records.

• Types of SCBA Units:

  • Open Circuit: Exhaled air released to the atmosphere.

  • Closed Circuit: Exhaled air is purified and recirculated.

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6.3 OCCUPATIONAL HEALTH

6.3.1 Definition (as per WHO)

• Occupational Health is defined by the World Health Organization (WHO) as:
  “The promotion and maintenance of the highest degree of physical, mental, and social well-being of workers in all occupations; the prevention of departures from health caused by their working conditions; the protection of workers from risks resulting from factors adverse to health; and the adaptation of work to man and of each man to his job.”

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6.3.2 Common Occupational Diseases

6.3.2.1 Causes, Risks, and Diagnostic Methods

• Occupations at Risk:

  • Mining, Foundry, Textile, Chemical, Construction, Welding, Painting, Agriculture, and Health sectors.

• Mode of Causation:

  • Physical Agents: Noise, vibration, radiation, extreme temperatures.

  • Chemical Agents: Gases, vapors, dust, fumes, solvents.

  • Biological Agents: Bacteria, viruses, fungi (hospital workers, lab staff).

  • Ergonomic Factors: Poor posture, repetitive work, heavy lifting.

• Common Occupational Diseases:

  • Pneumoconiosis: Due to inhalation of dust (Silicosis, Asbestosis, Coal Worker’s Pneumoconiosis).

  • Lead Poisoning: From exposure to lead compounds (battery, painting).

  • Noise-Induced Hearing Loss: Long-term exposure to high noise levels.

  • Skin Diseases: Dermatitis due to contact with chemicals or irritants.

  • Occupational Cancer: Due to exposure to carcinogens (asbestos, benzene).

  • Byssinosis: Cotton dust exposure in textile mills.

  • Bagassosis: Sugarcane fiber dust exposure.

  • Toxic Gas Poisoning: CO, H₂S, NH₃, Cl₂ in industrial environments.

• Diagnostic Methods:

  • Medical examination, biological tests, lung function tests, audiometry, chest X-rays, and laboratory investigations.

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6.3.2.2 Biological Monitoring, Prevention, and Compensation

• Biological Monitoring:

  • Measurement of toxins or metabolites in body fluids (blood/urine).

  • Examples: Blood lead level, urine phenol for benzene exposure.

• Prevention Methods:

  • Substitution of hazardous substances.

  • Engineering controls (ventilation, isolation).

  • PPE use.

  • Medical surveillance and training.

  • Periodic environmental monitoring.

• Compensation for Occupational Diseases:

  • Provided under Employees’ Compensation Act, 1923 (formerly Workmen’s Compensation Act).

  • Covers injury or disease arising out of and in the course of employment.

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6.3.2.3 Evaluation of Injuries

• Minor Injury: No lost time or short recovery.

• Major Injury: Results in lost work time, disability, or hospitalization.

• Evaluation Factors:

  • Nature of injury, part of body affected, duration of absence, and rehabilitation requirements.

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6.3.2.4 Occupational Health Management Services

• Aimed at promoting health and preventing occupational diseases.

• Components:

  • Pre-employment and periodic medical exams.

  • Health education and counseling.

  • First aid and emergency care services.

  • Maintenance of health records and statistical analysis.

  • Rehabilitation and return-to-work programs.

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6.3.2.5 Notifiable Diseases (Schedule III of the Factories Act, 1948)

• Employers must report these to authorities upon diagnosis.

• Examples include:

  1. Lead poisoning

  2. Manganese poisoning

  3. Arsenic poisoning

  4. Mercury poisoning

  5. Silicosis

  6. Asbestosis

  7. Byssinosis

  8. Bagassosis

  9. Chrome ulcer

  10. Occupational cancer

  11. Noise-induced hearing loss

  12. Phosphorus poisoning

  13. Benzene poisoning

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6.3.3 Occupational Health Hazards

6.3.3.1 Adverse Health Effects

• Noise: Hearing loss, stress, hypertension.

• Vibration: Hand-arm vibration syndrome, joint pain.

• Cold: Frostbite, hypothermia.

• Heat Stress: Heat exhaustion, heat stroke.

• Improper Illumination: Eye strain, fatigue, accidents.

• Thermal Radiation: Burns, dehydration.

• Ionizing Radiation: Cellular damage, cancer (X-rays, gamma rays).

• Non-Ionizing Radiation: Skin burns, eye injury (UV, microwave, laser).

6.3.3.2 Exposure Limits and Control

• Permissible Threshold Exposure Limits (PEL): Maximum safe exposure to physical agents (as per ACGIH/IS standards).

• Short-Term and Long-Term Effects:

  • Short-term: Temporary discomfort, irritation.

  • Long-term: Chronic diseases, organ damage.

• Preventive Measures:

  • Engineering controls (enclosures, insulation).

  • PPE (earmuffs, gloves, radiation shields).

  • Administrative controls (job rotation, rest breaks).

  • Regular monitoring and health checks.

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6.4 OCCUPATIONAL HEALTH PRACTICE

6.4.1 Common Occupational Diseases (Schedule III, Factories Act)

• Respiratory: Silicosis, Asbestosis, Byssinosis, Bagassosis.

• Skin: Dermatitis from chromium, nickel, and acids.

• Systemic Poisoning: Lead, arsenic, mercury, and phosphorus exposure.

• Cancer: Due to benzene, asbestos, and certain dyes.

• Hearing Loss: Caused by excessive industrial noise.

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6.4.2 Medical Examinations & Health Records

• Pre-employment Medical Examination:

  • Conducted before hiring to assess physical fitness and identify pre-existing illness.

• Periodical Medical Examination:

  • Conducted regularly to detect early signs of occupational disease.

• Medical Surveillance:

  • Continuous observation for exposure and health trends.

• Health Records:

  • Maintain medical, biological, and exposure data for each worker.

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6.4.3 Fundamentals of First Aid

• Burns:

  • Cool with water, cover with sterile dressing, avoid breaking blisters.

• Fractures:

  • Immobilize the part, avoid movement, send to hospital.

• Suffocation:

  • Remove from source, clear airway, provide artificial respiration.

• Toxic Ingestion:

  • Identify poison, seek medical help immediately, avoid inducing vomiting unless advised.

• Bleeding Wounds:

  • Apply pressure, elevate the limb, use sterile bandage.

• Bandaging:

  • To support, protect, and stop bleeding.

• Artificial Respiration:

  • Mouth-to-mouth or chest compression (CPR) until normal breathing resumes.

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Occupational Health – Practical Components

1. Lung Function Test:

   • Using Medspirator to assess respiratory capacity.

2. Ear Testing (Audiometry):

   • Demonstration of BA-3, Arphi, and Bakery Audiometer.

3. Study of Notifiable Diseases:

   • Using anatomical and photographic models.

4. Lung Models:

   • Sectional study to understand dust deposition and lung diseases.

5. Medical Laboratory Equipment Demonstration:

   • Vision tester, blood analyzer, ECG, and tetanus kits.

6. Charts & Posters for Health Education:

   • Industrial noise, dermatitis, physical and chemical health hazards.

7. Noise Control Charts:

   • Showing permissible exposure levels and control techniques.

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6.5 PHYSIOLOGY AND ERGONOMICS AT WORK

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6.5.1 Human Physiology and Workload Assessment

Basic Human Physiology

• Respiration:

  • Process of oxygen intake and carbon dioxide removal.

  • Supplies oxygen to tissues and removes waste gases.

• Cardiac Cycle:

  • Sequence of events during one heartbeat — systole (contraction) and diastole (relaxation).

  • Maintains blood flow and oxygen supply during work.

• Muscle Contraction:

  • Muscles contract due to interaction of actin and myosin filaments using ATP energy.

  • Enables lifting, pushing, pulling during work.

• Nerve Conduction:

  • Transmission of signals through neurons via electrochemical impulses.

  • Controls reflexes, coordination, and reaction during tasks.

Assessment of Workload

• Workload can be assessed through physiological parameters like:

  • Heart rate, pulse rate, oxygen consumption, energy expenditure, and sweat rate.

• Permissible Limits for Manual Handling:

  • Maximum load should depend on gender, posture, distance, and frequency.

  • As per ergonomic standards:

    • Males: ~50 kg occasionally, ~25 kg frequent lifts.

    • Females: ~30 kg occasionally, ~15 kg frequent lifts.

• Fixation Criteria:

  • Based on heart rate (should not exceed 110–120 bpm during sustained work).

  • Work–rest cycles are adjusted to keep fatigue minimal.

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6.5.2 Working Posture, Nutrition, and Health Implications

Working Posture

• Good Posture:

  • Reduces strain, ensures stability, and maintains energy efficiency.

• Bad Posture Effects:

  • Musculoskeletal disorders (back pain, neck strain, shoulder injury).

  • Poor blood circulation, varicose veins, and joint stiffness.

• Posture & Body Systems:

  • Cardiovascular: Poor posture hampers blood flow and increases heart strain.

  • Musculoskeletal: Causes repetitive strain injuries (RSI).

Nutrition in Manual Work

• Importance:

  • Provides energy and aids recovery from muscular stress.

  • Prevents fatigue, dehydration, and heat stress.

• Nutritional Requirements:

  • Balanced diet rich in carbohydrates, proteins, fats, vitamins, and minerals.

  • Extra salt and fluids for those working in hot environments.

• Work Nutrition Guidelines:

  • Small frequent meals.

  • Adequate hydration before, during, and after work.

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6.5.3 Work Capacity, Fatigue, and Rest Allowances

Assessment of Work Capacity

• Evaluated through ergometers or physical performance tests:

  • Bicycle Ergometer – measures leg muscle endurance.

  • Treadmill Test – measures overall aerobic capacity.

  • Step-stool Ergometer – measures oxygen consumption and recovery.

• Aerobic Capacity:

  • Maximum oxygen uptake (VO₂ max) that determines endurance.

  • Affected by age, gender, temperature, motivation, and training.

Fatigue

• Definition: Decline in performance due to overwork or energy depletion.

• Types:

  • Physical – muscular tiredness.

  • Mental – reduced alertness and concentration.

• Rest Allowance:

  • Short breaks restore efficiency and reduce accident risk.

  • Recommended: 10–15 min rest per hour in heavy work environments.

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6.5.5 Environmental Physiology (Practical Evaluation)

1. Evaluation of Environmental Stress (Heat)

• Objective: Assess worker’s heat exposure using thermal instruments.

• Equipment:

  • Psychrometer – measures humidity.

  • Kata Thermometer – air cooling power.

  • Globe Thermometer – radiant heat.

  • Stopwatch – for time measurements.

  • Psychrometric & ET/CET charts – determine comfort zone.

• Parameters Studied:

  • Wet Bulb Globe Temperature (WBGT), air velocity, and relative humidity.

2. Physical Fitness Index (PFI) Test

• Evaluates general endurance using:

  • Step test stool (height 46 cm), metronome, and stopwatches.

  • Measures recovery heart rate after physical exertion.

3. Respiratory Physiology

• Tests used to evaluate pulmonary function:

  • Spirometer – measures lung volume and capacity.

  • Peak Flow Meter – measures airflow rate and obstruction.

4. Anthropometry

• Definition: Measurement of human body dimensions for ergonomic design.

• Tools:

  • Anthropometer, Calipers, Skinfold Caliper, Weighing Machine.

• Applications:

  • Designing workstations, tools, PPE, and seating to fit human dimensions.

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6.6 ERGONOMICS

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6.6.1 Introduction to Ergonomics

Definition:

• Ergonomics = Science of fitting the job to the worker, aiming to enhance safety, efficiency, and comfort.

Aims and Scope

• To minimize fatigue and human error.

• To improve safety, productivity, and health.

• To design tools, workstations, and environments suited to human capabilities.

Man–Machine–Environment System

• Interaction between:

  • Man (operator) – physical & mental capability.

  • Machine – tool, equipment, control system.

  • Environment – temperature, lighting, noise.

• Each element must complement others for optimum performance.

Constituents of Ergonomics

• Physical ergonomics: Posture, workplace layout, material handling.

• Cognitive ergonomics: Decision-making, workload, mental stress.

• Organizational ergonomics: Work scheduling, teamwork, job design.

Applications in Industry

• Reduces accidents and fatigue.

• Improves efficiency, comfort, and job satisfaction.

• Used in control rooms, vehicle design, computer workstations, and assembly lines.

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6.6.2 Ergonomics of Automation and Rehabilitation

Automation & Assembly Work

• Ergonomic Concerns:

  • Monotony, repetitive motion, poor seating, and visual strain.

• Visual Fatigue:

  • Caused by poor lighting or continuous screen focus.

  • Preventive Measures: Adjustable illumination, anti-glare screens, rest pauses.

Ergonomics in Rehabilitation

• Designing alternate jobs for injured or partially disabled workers.

• Use of adjustable workstations, low-load tasks, and supportive tools.

Anthropometry & Biomechanics

• Anthropometry: Measurement of human body dimensions.

• Biomechanics: Study of forces and movements in human body.

• Applications:

  • Tool and workstation design.

  • Determining lifting limits and posture angles.

  • Reducing strain on muscles and joints.

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6.6.3 Ergonomic Design of Workstation

Concept of Workstation

• The immediate area where a worker performs a job, including tools, controls, and displays.

Principles of Design

1. Fit the workstation to the user (not the reverse).

2. Proper reach and visibility zones for all controls.

3. Adjustable chairs and tables for height and comfort.

4. Adequate legroom and lighting.

5. Minimize repetitive motion and awkward postures.

Improving Safety and Productivity

• Reduces fatigue and musculoskeletal disorders.

• Increases output and job satisfaction.

• Enhances accuracy and lowers human error.

Technical and Engineering Controls

• Use of adjustable tools and equipment.

• Mechanical aids for material handling.

• Anti-vibration mounts, ergonomic seating, and noise control.

Economic Considerations

• Though initial investment may be high, ergonomic design reduces:

  • Absenteeism, injuries, medical cost, and training time.

  • Increases productivity and long-term cost savings.

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✅ Summary

• Ergonomics integrates physiology, psychology, and engineering to design safe, healthy workplaces.

• It ensures optimum human performance, prevents fatigue and injuries, and promotes well-being and efficiency.