Tungsten Inert Gas (TIG) welding is a precision welding process widely used in Kenya's manufacturing, automotive, and fabrication sectors due to its ability to produce high-quality, clean welds on a variety of metals including stainless steel and aluminium. Mastery of TIG welding techniques is essential for professionals aiming to meet the exacting standards required in industries such as medical equipment fabrication, aerospace component production, and automotive repair workshops. This chapter focuses on the critical occupational health and safety standards that govern TIG welding operations, ensuring that welders protect themselves and their colleagues while delivering exceptional workmanship.

2.1 Occupational Health and Safety Standards

Occupational health and safety (OHS) standards are crucial in TIG welding to prevent work-related injuries and illnesses. Kenyan welding workshops and industrial sites enforce these standards to comply with the Occupational Safety and Health Act (OSHA) 2007 and regulations by the Directorate of Occupational Safety and Health Services (DOSHS). Understanding and applying OHS standards reduces hazards from electric shock, ultraviolet radiation, fumes, and hot metals that are common in TIG welding environments.

2.1.1 Personal Protective Welding Equipment

Personal protective equipment (PPE) is the frontline defense against the diverse hazards encountered during TIG welding. Welders in Kenya’s industrial and fabrication sectors must equip themselves appropriately to comply with safety regulations and protect their health.

Components of Personal Protective Equipment

• Welding Helmet with Auto-Darkening Filter: Protects the eyes and face from intense ultraviolet and infrared radiation, sparks, and spatter. Auto-darkening helmets adjust lens shade automatically, enhancing visibility and reducing eye strain during welding.
• Welding Gloves: Made of heat-resistant leather, gloves protect hands from burns, electric shock, and sharp metal edges. Properly fitting gloves ensure dexterity while handling the tungsten electrode and filler rods.
• Protective Clothing: Flame-resistant jackets or aprons made from leather or treated cotton prevent burns from sparks and hot metal. Covering all exposed skin is vital to prevent arc flash injuries.
• Respiratory Protection: Depending on ventilation, respirators or masks filter hazardous welding fumes and gases, especially when welding stainless steel or galvanized materials which emit toxic fumes.
• Safety Boots: Steel-toe boots protect feet from heavy falling objects and hot metal while providing electrical insulation in some designs.

worn black safety boots on wooden floor (Source: Wikipedia (Steel-toe boot))

Importance of PPE Compliance

Welders at Nairobi County's metal fabrication workshops who consistently use PPE report fewer incidents of burns and eye damage, highlighting PPE’s role in maintaining workforce health and productivity. Employers must enforce PPE usage through training and supervision to comply with Kenyan occupational safety laws.

2.1.2 Workshop Safety

A safe workshop environment is foundational to preventing accidents and ensuring smooth TIG welding operations. Safety management within Kenyan welding workshops involves infrastructure design, hazard control, and emergency preparedness.

Essential Elements of Workshop Safety

• Ventilation Systems: Effective extraction and ventilation remove harmful welding fumes and gases, maintaining air quality. Workshops in Nairobi’s industrial zones install local exhaust ventilation near welding stations to comply with health standards.
• Fire Prevention Measures: Welding areas must be free from flammable materials, with fire extinguishers and blankets readily accessible. Regular fire drills and training prepare staff for prompt response.
• Clear Signage and Markings: Warning signs indicating welding zones, high voltage areas, and PPE requirements guide personnel and visitors to maintain safe distances and precautions.
• Housekeeping Practices: Keeping the workshop clean and organized reduces tripping hazards and fire risks. Scrap metals, cables, and tools must be stored properly after use.
• Emergency Exits and First Aid Facilities: Clearly marked emergency exits and accessible first aid kits ensure quick evacuation and response to injuries.

2.1.3 Workplace Procedures

Workplace procedures standardize welding activities to ensure safety and quality. Kenyan welding firms develop and enforce procedures aligned with OSHA requirements and industry best practices.

Key Welding Workplace Procedures

• Pre-Operation Checks: Inspecting welding machines, gas cylinders, and PPE before starting work prevents equipment failure and accidents.
• Lockout/Tagout Practices: Ensuring welding equipment is isolated from power sources during maintenance protects technicians from electric shock.
• Safe Gas Cylinder Handling: Storing cylinders upright, securing them properly, and checking for leaks prevent explosions and gas exposure.
• Work Permit Systems: Authorizing welding activities through permits controls hazardous operations, especially in confined spaces or near flammable materials.
• Incident Reporting and Investigation: Prompt reporting of accidents or near misses enables corrective actions, improving overall workplace safety.

2.1.4 Welding Hazards

TIG welding exposes workers to multiple hazards that can cause acute injuries or long-term health effects. Awareness and management of these hazards are essential for Kenyan welders to maintain safe working conditions.

Common TIG Welding Hazards

• Electric Shock: TIG welding uses high voltage and current; improper handling of cables or equipment can cause fatal shocks.
• Ultraviolet and Infrared Radiation: The welding arc emits intense radiation that can cause "arc eye" or retinal burns without proper eye protection.
• Fumes and Gases: Welding stainless steel or coated metals produces hazardous fumes containing chromium, nickel, and zinc oxides which can cause respiratory diseases.
• Fire and Explosion Risks: Sparks and molten metal can ignite flammable materials nearby, especially in workshops handling fuel or solvents.
• Noise Exposure: Welding operations and associated machinery generate noise levels that can lead to hearing loss without protection.

2.1.5 Safe Handling of Equipment

Proper handling and maintenance of TIG welding equipment prolongs its lifespan and safeguards the welder from accidents. Kenyan welding workshops emphasize equipment care as part of their OHS compliance.

Guidelines for Equipment Handling

• Correct Setup of Welding Machines: Ensuring correct polarity, amperage, and gas flow settings prevents equipment damage and poor weld quality.
• Regular Inspection and Maintenance: Checking cables, torches, regulators, and gas hoses for wear or damage avoids breakdowns and hazards.
• Safe Storage of Consumables: Tungsten electrodes and filler rods must be stored dry and protected from contamination to maintain weld integrity.
• Handling Gas Cylinders Safely: Transporting cylinders with trolleys and using protective caps prevents physical damage and leaks.
• Proper Shutdown Procedures: Turning off power and gas supplies after welding prevents unintended ignition or electric hazards.

Chapter Summary

This chapter on carrying out Tungsten Inert Gas (TIG) welding emphasizes the importance of adhering to occupational health and safety standards, including the use of personal protective equipment, maintaining workshop safety, following workplace procedures, identifying welding hazards, and ensuring safe handling of equipment. Effective housekeeping practices such as cleaning and waste management are necessary to maintain a safe and organized work environment. Understanding and interpreting working drawings, including symbols, notations, abbreviations, and parts lists, is essential for accurate welding preparation. The chapter details TIG welding equipment and accessories, their types, uses, and proper care to ensure optimal performance. Preparation of welding materials up to 10 mm thickness involves precise measuring, marking out, cutting, and edge preparation to achieve quality welds. Key TIG welding parameters such as current, arc force, voltage, and gas pressure must be correctly set for successful welding operations. The chapter also covers essential MIG welding tools, their types, and maintenance. It describes the TIG welding process, its procedures, and applications, alongside the types of metallic materials commonly welded, including plates and pipes. Various welding positions and joint types are explained with their specific applications, while common weld defects, their causes, and prevention methods are thoroughly discussed. Finally, finishing processes like polishing, grinding, blueing, varnishing, oil blacking, deburring, and painting are outlined, concluding with practical TIG welding of metallic plates and pipes in the flat position.