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, 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 equipment

Personal protective equipment (PPE) is the frontline defence against the diverse hazards encountered during TIG welding. Example: a welder joining stainless steel tube in a fabrication workshop wears a helmet, gloves, protective clothing and boots before striking the first arc, because each item guards against a different hazard. 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 galvanised 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.
• Hearing protection: Ear plugs or ear muffs reduce the noise of grinding and nearby machinery, which is worn during long shifts to prevent gradual hearing loss.

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

Importance of PPE compliance

A welder who wears the full set of PPE on every job is far less likely to suffer burns, arc eye or fume-related illness than one who skips items on short jobs. This protects both the welder's health and the workshop's productivity, since injuries mean lost working days. 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. Example: a fabrication workshop with marked welding bays, extraction at each bay and a clear exit route lets several welders work at once without exposing each other to arc flash or fumes. 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. A workshop may install local exhaust ventilation near each welding station to meet 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.
• Welding screens and bays: Non-reflective screens or curtains around each welding station stop arc light from reaching other workers and visitors passing nearby.
• Emergency exits and first aid facilities: Clearly marked emergency exits and accessible first aid kits ensure quick evacuation and response to injuries.
• Electrical safety of the premises: Earthed sockets, undamaged power cables and dry floors around the welding machine reduce the risk of shock from the supply.

2.1.3 Workplace procedures

Workplace procedures standardise welding activities to ensure safety and quality. Example: before a shift, a welder follows the workshop's checklist to inspect the machine, torch, gas hoses and PPE, and only then starts welding. 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 and tagout practices: Ensuring welding equipment is isolated from power sources during maintenance protects technicians from electric shock. A lock and a tag on the isolator show that the machine must not be switched on.
• Work permit systems: Authorising 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.
• Emergency response procedure: Every worker should know how to raise the alarm, switch off the machine and gas supply, use the nearest extinguisher safely and reach the assembly point.
• Induction and training: New welders are briefed on the workshop's hazards, rules and emergency arrangements before they touch any equipment.

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. A welder who knows each hazard and its control can work confidently on stainless steel, mild steel and aluminium jobs.

2.1.4.1 Types

• Electric shock: The machine runs from the mains supply and the welding circuit carries high current, so damaged cables, wet floors or bare connections 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, and can burn exposed skin like sunburn.
• 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.
• Burns from hot metal: Freshly welded workpieces and the torch remain hot long after the arc stops and burn bare skin on contact.
• Compressed gas cylinders: A falling or damaged argon cylinder can injure workers or release gas, and leaking gas in a closed room can displace breathable air.
• Grinding dust and flying particles: Sharpening tungsten electrodes and grinding plate edges throws off dust and fragments that harm the eyes and lungs.

2.1.4.2 Prevention and control

• Preventing electric shock: Use cables with undamaged insulation, keep connections tight, work on dry floors, wear dry gloves and make sure the machine is properly earthed.
• Controlling radiation: Wear a helmet with the correct shade, cover all skin, and use screens so that nearby workers are not exposed to the arc.
• Controlling fumes: Use local exhaust ventilation, keep your head out of the fume plume, wear a suitable respirator where extraction is not enough, and remove paint or coatings from the joint before welding.
• Preventing fire: Clear flammable materials from the welding area, keep an extinguisher and fire blanket at hand, and check the area for smouldering after welding is finished.
• Reducing noise and burns: Wear ear protection near noisy tasks, handle hot workpieces with tongs or gloves, and label hot parts so others do not touch them.
• Controlling dust: Grind electrodes and plate edges with extraction or in a ventilated area, and wear eye protection and a dust mask.

2.1.5 Safe handling of equipment

Proper handling and maintenance of TIG welding equipment prolongs its lifespan and safeguards the welder from accidents. Example: a welder who coils cables neatly, caps the cylinder and switches off the gas after work avoids tripping hazards, leaks and damaged equipment. Kenyan welding workshops emphasise 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: Store and use cylinders upright and secured with a chain or strap, move them with trolleys, keep protective caps on when not in use, and check connections for leaks with soapy water.
• 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.