Manual metal arc welding (MMAW) is a fundamental welding process widely used in Kenya's construction, manufacturing, and repair sectors. Mastery of MMAW techniques requires not only technical skill but also strict adherence to occupational health and safety standards to protect welders and their work environment. This chapter explores essential safety regulations, risk management, ergonomic considerations, and environmental safeguards that welding professionals must implement to maintain a safe and efficient workshop.

1.1 Occupational health and safety standards

Occupational health and safety (OHS) standards are critical in the welding profession due to the inherent hazards of arc welding processes, including exposure to electric shock, fumes, UV radiation, and fire risks. In Kenya, compliance with OHS legislation and best practices ensures that welders operate in safe conditions, preventing injuries and promoting long-term wellbeing. Welding workshops must integrate comprehensive safety frameworks that cover legal requirements, risk assessments, emergency protocols, and environmental controls.

1.1.1 Workplace legislation and standards

Welding professionals must understand the legal framework governing workplace safety in Kenya to comply with national regulations and international best practices. The primary legislation includes the Occupational Safety and Health Act (OSHA) 2007, which places duties on employers to provide a safe working environment and on employees to follow safety protocols. Additionally, standards from bodies such as the Kenya Bureau of Standards (KEBS) and the International Labour Organization (ILO) inform specific welding safety requirements.

Example: a welder starting work in a fabrication workshop should be able to point to the PPE issued, the training received and the place where incidents are recorded, because each of these follows from the duties set out in the Act.

Legal requirements for welding workplaces

• Provision of Personal Protective Equipment (PPE): Employers must supply appropriate PPE such as welding helmets, gloves, aprons, and respiratory protection to safeguard workers from arc rays, sparks, and fumes.
• Safety training and certification: Welders should undergo regular safety training and obtain certification to ensure competence in handling equipment and recognising hazards.
• Hazard identification and control: Employers are legally required to identify welding hazards and implement control measures, including ventilation systems and fire prevention.
• Reporting and documentation: Workplace injuries and incidents must be reported and documented as stipulated by OSHA 2007 to facilitate investigations and preventive measures.
• Workplace inspections and audits: Regular inspections by safety officers ensure continuous compliance with safety standards and identify areas needing improvement.

National and international standards relevant to MMAW

• KEBS standards for welding equipment: These address the safety and performance of welding machines and accessories used in Kenya.
• ISO 15614 for welding procedure qualification: This international standard guides the qualification of welding procedures to ensure quality and safety.
• ILO guidelines on occupational safety: These provide frameworks for safe working conditions, including guidance on controlling exposure to welding fumes and radiation.
• Work Injury Benefits Act (WIBA) 2007: This act provides for compensation of workers for work-related injuries and diseases, and therefore applies to welding workshops.
• Environmental Management and Coordination Act (EMCA): This act addresses environmental safety concerns related to welding operations, such as waste disposal and pollution control.

Roles and responsibilities under Kenyan legislation

• Employers: Must provide safe equipment, training, and a hazard-free environment.
• Employees: Are required to use PPE correctly and adhere to safety procedures.
• Safety officers: Oversee compliance, conduct risk assessments, and coordinate emergency responses.
• Safety and health committee: Brings management and workers together to discuss hazards, review incidents and recommend improvements.
• Government agencies: Enforce regulations through inspections and sanctions for non-compliance.

1.1.2 Risk Assessment

Risk assessment is a systematic process of identifying, analysing, and controlling hazards in the welding workplace. It is essential for preventing accidents and ensuring that welding operations comply with safety standards. Welding supervisors and safety officers carry out risk assessments regularly so that controls are adapted to changing workshop conditions.

Example: before a group welds a steel gate frame with MMAW, the supervisor walks the bay and records the shock risk from worn cables, the fire risk from paint tins nearby and the fume risk from poor airflow.

Steps in conducting welding risk assessments

1. Define the task and area: State the job to be assessed, for example butt welding mild steel plate with E6013 electrodes in a welding bay, and who will be exposed.
2. Hazard identification: Recognise all potential sources of harm such as electric shock, fumes, fire, and noise in the welding area.
3. Risk analysis: Determine the likelihood and severity of injury or damage associated with each hazard.
4. Risk evaluation: Prioritise risks based on their impact and probability to decide which hazards require immediate control.
5. Implementation of control measures: Apply elimination, substitution, engineering controls, administrative controls, and PPE to reduce risks.
6. Recording and communication: Write down the findings and controls on the assessment form and explain them to everyone doing the job.
7. Monitoring and review: Continuously check the effectiveness of controls and update the risk assessment after any incident or change of process, material or layout.

Common welding hazards requiring assessment

• Electric shock: Contact with live parts, damaged cable insulation or a wet workpiece can cause fatal injuries.
• Fume inhalation: Welding fumes contain toxic metals such as manganese and chromium, depending on the base metal and electrode.
• Ultraviolet (UV) radiation: Exposure can cause "arc eye" and skin burns.
• Fire and explosion: Sparks may ignite flammable materials nearby.
• Noise: Chipping, grinding and hammering produce noise that can damage hearing.
• Ergonomic hazards: Poor posture and repetitive movements can lead to musculoskeletal disorders.

Risk control hierarchy applied in welding

• Elimination: Remove the hazard entirely, for example by redesigning a job so that welding is done in a workshop bay rather than at height.
• Substitution: Use less hazardous materials or welding methods.
• Engineering controls: Install ventilation systems to remove fumes and screens to prevent radiation exposure to others.
• Administrative controls: Schedule work to limit exposure time and provide training.
• Personal protective equipment: Use helmets, gloves, and respirators as the last line of defence.

1.1.3 Workshop Incident/Accident

Incident and accident management are crucial in welding workshops to minimise harm and improve safety culture. An incident refers to any unplanned event that could have resulted in injury or damage, while an accident is an event that causes actual harm. Welding workshops must establish clear procedures to report, investigate, and learn from these events.

1.1.3.1 Nature

Incidents and accidents in a welding workshop range from near misses, where nobody is hurt, to injuries that stop a worker from working or even cause death. Understanding the nature of each type helps a welder recognise early warnings. Example: an electrode holder with cracked insulation that gives a tingle to the hand is a near miss, but if it is ignored it can become a serious shock.

Typical events in MMAW workshops include:

• Electric shock incidents: Occur due to faulty equipment, damaged cables or improper handling in damp conditions.
• Burn injuries: Result from contact with hot metal, sparks, or molten slag.
• Arc eye and skin burns: Result from exposure to arc radiation without correct eye and skin protection.
• Falls and trips: Caused by cluttered workspaces, trailing cables or poor housekeeping.
• Inhalation-related illnesses: Due to prolonged exposure to welding fumes.
• Equipment failures: Leading to mechanical injuries or fires.

1.1.3.2 Causes

Most workshop accidents come from a combination of unsafe acts by people and unsafe conditions in the workplace, both of which usually trace back to weaknesses in management or training. Identifying the cause is the first step in preventing a repeat. Example: a welder who slips on stray electrode stubs has been injured by the stubs, but the real cause is the absence of a housekeeping routine.

• Faulty or damaged equipment: Worn cable insulation, loose connections and damaged electrode holders expose the welder to shock and burns.
• Failure to use PPE: Working without a helmet, gloves or leather apron exposes the body to arc rays, sparks and spatter.
• Poor housekeeping: Cables across walkways, scattered offcuts and stubs and oil spills cause trips and falls.
• Inadequate ventilation: Fumes build up in confined or crowded bays and affect health and concentration.
• Flammable materials near the work area: Sparks and hot spatter ignite paint, rags, fuel or wood.
• Lack of training and supervision: Untrained workers take shortcuts or misuse machines because they do not understand the hazards.
• Fatigue and rushing: Tired or hurried welders make errors of judgement, such as touching hot work without gloves.

Root cause analysis looks beyond the immediate event to underlying causes such as human error, equipment failure or unsafe conditions, so that the corrective action addresses the real problem.

1.1.3.3 Prevention

Prevention combines good equipment condition, safe working habits and a well-organised workshop. Controls are chosen using the risk control hierarchy and checked regularly. Example: a welder who inspects the cables and earth clamp before each job, wears dry gloves and stands on an insulating mat greatly reduces the chance of shock.

• Inspect equipment before use: Check cables, electrode holders, earth clamps and machine casings, and withdraw damaged items for repair.
• Enforce PPE use: Insist on helmet, gloves, apron, safety boots and suitable clothing for every welding task.
• Maintain housekeeping: Keep floors, walkways and exits clear and collect stubs and offcuts as work proceeds.
• Control fire risks: Remove or cover flammable materials, keep an extinguisher within reach and check the area after welding.
• Provide ventilation and fume extraction: Draw fumes away from the welder's breathing zone, especially for confined or poorly ventilated work.
• Train and supervise: Teach safe procedures to new and experienced workers and monitor how they work.
• Use screens and signs: Protect other people from arc flash and warn visitors of welding areas.
• Learn from near misses: Report and discuss them so that hazards are corrected before someone is hurt.

1.1.3.4 Report

Reporting turns an event into learning. A prompt, accurate report allows the workshop to give help, meet legal duties and prevent recurrence. Reports must be made for accidents and for near misses.

Procedure for incident reporting and investigation:

1. Immediate reporting: Workers must notify the supervisor of any incident without delay and call for first aid where anyone is hurt.
2. Making the area safe: Switch off the machine, remove ignition sources and make sure no one else is at risk.
3. Securing the scene: Preserve the area, as far as is safe, to prevent further harm and facilitate investigation.
4. Data collection: Gather witness statements, photographs, and equipment logs.
5. Root cause analysis: Identify underlying causes such as human error, equipment failure, or unsafe conditions.
6. Completing the report form: Record the date, time, place, persons involved, injuries, description of events and immediate action taken, and notify the authority where the law requires it, as stipulated by OSHA 2007.
7. Corrective actions and follow-up: Implement measures to prevent recurrence, such as equipment repair or revised procedures, and check that they work.

Importance of incident documentation and follow-up: accurate records help organisations identify patterns, comply with legal requirements, and improve training programmes. Example: if records show several burn injuries from spatter in one bay, a workshop can review its PPE rules, such as sleeve and glove standards, and supervise their use more closely.

1.1.4 Workplace ergonomics and work design

Ergonomics in welding focuses on designing the workplace and tasks to fit the worker, reducing fatigue, discomfort, and injury risk. Proper ergonomic design increases productivity and quality of welding work. Workshops often face challenges such as limited space and inadequate equipment, making ergonomic considerations vital.

Example: a welder who welds a long frame on a low bench for hours will bend the back and tire quickly, but raising the work to a comfortable height improves control of the arc and the quality of the bead.

Principles of ergonomic work design in welding

• Adjustable workstations: Allow welders to position workpieces and seating to maintain neutral postures.
• Tool design: Use lightweight, well-balanced electrode holders and grinders to reduce strain.
• Work-rest cycles: Incorporate breaks to prevent repetitive strain injuries.
• Lighting: Provide adequate illumination to reduce eye strain and improve precision.
• Material handling: Use mechanical aids for heavy loads to prevent back injuries.

Common ergonomic issues in welding environments

• Awkward postures: Prolonged bending, kneeling or twisting, especially in vertical and overhead positions, can cause musculoskeletal pain.
• Repetitive motions: Continuous electrode manipulation and chipping may lead to tendonitis.
• Vibration exposure: Hand-held grinders can cause hand-arm vibration syndrome.
• Static muscle loading: Holding the electrode holder steady for long periods fatigues muscles.
• Insufficient breaks: Lead to cumulative trauma disorders.

Strategies for improving welding ergonomics

• Ergonomic training: Teach welders proper body mechanics and safe tool use.
• Workspace organisation: Arrange tools and materials within easy reach.
• Use of support devices: Employ welding stools, clamps, positioners and adjustable tables.
• Job rotation: Alternate welders between tasks to vary muscle use.
• Regular ergonomic assessments: Identify and address emerging issues promptly.

1.1.5 Workplace environmental safety

Environmental safety in welding workshops involves managing the impact of welding activities on the surrounding environment and ensuring compliance with environmental laws. Workshops must control emissions, waste, and noise pollution to protect workers and neighbouring communities. Example: slag, stubs, used grinding discs and oily rags all leave the workshop in some form, so each needs a planned route.

1.1.5.1 Impact of waste and by-products

Arc welding and its supporting processes produce fumes, gases, solid waste and noise as by-products. If uncontrolled, they harm the health of workers and pollute air, soil and water around the workshop.

• Air pollution: Welding fumes and gases such as ozone and nitrogen oxides affect the lungs and the surrounding air.
• Solid waste generation: Slag, used electrode stubs, spatter, offcuts and used abrasive discs accumulate and can injure workers or pollute soil if dumped carelessly.
• Contaminated waste: Oily rags, used oil, solvents and paint residues can contaminate soil and water and are also a fire risk.
• Noise pollution: Welding, chipping and grinding produce noise levels harmful to hearing and disturbing to neighbours.
• Fire hazards: Sparks may ignite combustible waste and materials in the environment.
• Energy consumption: Inefficient welding equipment increases electricity or fuel use and the carbon footprint.

Controls that reduce these impacts include:

• Fume extraction systems: Capture and filter welding fumes at the source.
• Noise control measures: Use ear protection and sound barriers.
• Fire prevention: Maintain clear work areas free of flammable substances.
• Energy-efficient equipment: Use modern welding machines with lower power consumption and switch them off when not in use.

Welding workshops must adhere to EMCA and local environmental policies. Example: a workshop whose environmental audit shows excessive fume in the working area may install extraction units at the welding bays.

1.1.5.2 Workshop waste management

Waste management is the planned handling of waste from its creation to its final disposal. In a welding workshop it rests on three activities: keeping the workplace clean, sorting waste by type, and disposing of each type safely and lawfully.

1.1.5.2.1 Housekeeping activities

Good housekeeping prevents trips, fires and contamination, and makes the other stages of waste management easier. It is done continuously during work and not only at the end of the day.

• Sweeping and collecting: Remove electrode stubs, slag chips, spatter and metal dust from floors and benches regularly.
• Keeping walkways and exits clear: Do not leave offcuts, plates, cylinders or tools in aisles or in front of exits and extinguishers.
• Managing cables: Coil leads and route them overhead or along walls to prevent trips and damage.
• Cleaning spills: Wipe up oil and water immediately and use absorbent material where needed.
• Returning tools and materials: Put chipping hammers, wire brushes, clamps and electrodes in their storage places after use.
• Cleaning equipment: Wipe machines and remove dust from vents so that they do not overheat.

1.1.5.2.2 Sorting

Sorting means separating waste at the point where it is produced, so that recyclable, general and hazardous waste are not mixed. Labelled or colour-coded containers placed in the workshop make this easy for everyone.

1.1.5.2.3 Disposal

Disposal is the final step and must prevent harm to people and the environment. Hazardous waste in particular must never be burned, buried or poured into drains.

1. Allow hot waste to cool: Place hot slag and stubs in a metal container, never in plastic bins or near combustibles.
2. Store in labelled containers: Keep each waste type in its own container until collection.
3. Send scrap metal for recycling: Sell or hand over clean metal to scrap dealers.
4. Hand hazardous waste to licensed handlers: Dispose of used oil, solvents and contaminated materials through licensed waste handlers in line with EMCA guidelines.
5. Avoid unsafe methods: Do not burn waste, pour oil into drains or dump on open ground.
6. Keep records: Note the type and quantity of waste removed and who collected it.
7. Review regularly: Check the waste areas and bins weekly and reduce waste where possible.

1.1.6 Workshop safety

Workshop safety encompasses all measures taken to prevent accidents and injuries within the welding workspace. Effective workshop safety management creates a culture of vigilance and responsibility among workers, minimising hazards specific to MMAW.

Essential safety practices in welding workshops

• Clear signage: Display hazard warnings and safety instructions prominently.
• Fire safety equipment: Provide fire extinguishers, fire blankets, and emergency exits.
• Electrical safety: Regularly inspect welding cables, connectors, and machines for faults.
• Welding screens: Use screens or curtains so that other people are protected from arc flash.
• Hot work control: Clear or cover flammable materials near the work and check the area after welding for smouldering.

Common workshop safety challenges

• Inadequate PPE usage: Workers neglecting helmets or gloves increase injury risk.
• Poor ventilation: Leads to accumulation of toxic gases and heat.
• Unsafe storage: Flammable materials stored improperly near welding zones.
• Unauthorised access: Visitors entering welding areas without protective gear.
• Fatigue and distractions: Resulting in lapses of concentration and accidents.

Measures to enhance workshop safety culture

• Incentive programmes: Reward safe behaviour and reporting of hazards.
• Supervisory oversight: Monitor compliance and provide real-time feedback.
• Incident analysis: Use near-miss reports to identify potential risks.
• Worker participation: Involve welders in safety inspections and in suggesting improvements.
• Continuous training: Update workers on new safety technologies and procedures.

1.1.6.1 Layout

The layout of a welding workshop determines how safely people, materials and equipment move and how far a fire or arc flash can spread. A good layout separates hazardous activities, keeps routes clear and places safety equipment where it is needed. Example: a workshop that places the grinding area away from the welding bays and the paint store keeps sparks away from flammable liquids.

• Separate welding bays: Provide marked bays with screens or curtains so that arc flash does not reach people passing by.
• Distance from flammables: Keep paint, fuel, solvents and oily rags in a separate store away from welding and grinding areas.
• Machine and cable arrangement: Place machines on a firm, dry floor near power outlets, with cable routes that do not cross walkways.
• Clear aisles and exits: Mark walkways and keep emergency exits unobstructed and visible.
• Ventilation and extraction: Position bays where air movement or fume extraction carries fumes away from the welder's breathing zone.
• Lighting: Light work areas, benches and walkways evenly to reduce eye strain and errors.
• Fire equipment placement: Mount extinguishers and fire blankets at visible, accessible points near exits and welding bays.
• Material flow: Arrange storage, preparation, welding and finishing in logical order so that heavy parts are not carried through busy areas.

1.1.7 Workplace procedures

Workplace procedures define standardised methods for performing welding tasks safely and efficiently. Clear procedures reduce variability, ensure compliance with safety standards, and improve quality outcomes in MMAW operations.

Components of effective welding workplace procedures

• Pre-welding checks: Inspection of equipment, PPE, and work area before starting.
• Safe welding practices: Guidelines on electrode selection, arc striking, and welding positions.
• Handling of materials: Procedures for lifting, storing, and moving metal parts safely.
• Hot work authorisation: Confirmation that the area has been checked and fire protection arranged before welding outside designated bays.
• Post-welding activities: Cooling, slag removal, and equipment maintenance instructions.

Benefits of standardised workplace procedures

• Reduced accidents: Consistent application of safety measures lowers injury rates.
• Improved productivity: Clear steps minimise downtime and errors.
• Quality assurance: Uniform methods produce more reliable welds.
• Regulatory compliance: Demonstrates commitment to legal and safety obligations.
• Worker confidence: Clear instructions empower welders to work safely and efficiently.

1.1.7.1 Compliance

Compliance means that every worker follows the workshop procedures and the legal requirements behind them. It does not depend on written rules alone, but on checking and correcting how work is actually done. Example: a supervisor who sees a welder striking an arc without gloves stops the work and corrects it at once.

• Compliance monitoring: Supervisors enforce adherence and provide corrective guidance.
• PPE checks: Confirm before each job that correct PPE is worn and in good condition.
• Equipment inspections: Make sure machines, cables and extinguishers are inspected at set intervals and tagged where faulty.
• Safety audits: Compare actual practice with procedures and legal requirements and record gaps.
• Corrective action: Retrain, warn or discipline workers who break safety rules, according to workshop policy.
• Legal compliance: Keep workshop practices aligned with OSHA 2007, WIBA 2007 and EMCA.

1.1.7.2 Documentation

Documentation provides written proof that procedures exist, are known and are followed. It supports training, investigations and inspections. Example: an equipment log showing the date each welding machine was last inspected lets a supervisor see which machines are overdue.

• Procedure manuals and job aids: Produce clear, accessible instructions for common tasks and keep them near the work area.
• Risk assessment records: Keep the completed assessments for each task and update them after changes.
• Inspection and maintenance logs: Record checks on machines, cables, extinguishers and extraction units.
• Training records: Note who was trained, on what, and when.
• Incident and near-miss register: Record every event, its causes and the corrective action taken.
• Hot work permits and waste records: Keep permits and waste disposal records for later checks.
• Regular review: Update procedures in response to incidents or technological changes.

1.1.7.3 Communication

Safety depends on information reaching the right people clearly and on time. Communication covers instructions from supervisors, warnings between workers and the channels through which hazards are reported. Example: a welder working inside a tank agrees signals with a helper outside before starting.

• Consultation with stakeholders: Involve welders, supervisors, and safety officers when preparing or changing procedures.
• Toolbox talks: Hold short briefings before work on the hazards of the day's task and the controls to use.
• Safety signs and notices: Use standard signs, colours and notices to warn of hazards and show required PPE.
• Clear instructions between workers: Agree verbal or hand signals for switching off machines and for emergencies.
• Shift handover: Report faulty equipment and unfinished hot work to the next shift.
• Hazard reporting channels: Make it easy and safe for workers to report hazards and near misses to the supervisor.

1.1.7.4 Emergency procedures

Emergency procedures set out what each person must do immediately when a fire, electric shock, serious injury or other emergency occurs. They must be known by all workers and practised in drills so that people react correctly under stress. Example: every welder should know where the nearest extinguisher, first aid kit, isolator switch and assembly point are.

General emergency response:

1. Stop work and make safe: Switch off the welding machine and isolate the power if it is safe to do so.
2. Raise the alarm: Shout, sound the alarm and alert the supervisor and first aider.
3. Give first aid: A trained person attends to casualties without putting themselves at risk.
4. Fight a small fire only if safe: Use the correct extinguisher, never water on an electrical fire, and evacuate if the fire is spreading.
5. Evacuate: Leave by the nearest clear exit to the assembly point.
6. Call for help: Contact the emergency services and give the location and nature of the emergency.
7. Account for everyone: Check that all workers and visitors are present and report missing persons.
8. Report and review: Record the event and review the procedure afterwards.

Specific emergencies in MMAW work:

• Electric shock: Switch off the power at the isolator before touching the casualty, or separate them using dry insulating material, then give first aid and call for medical help.
• Burns: Cool the burn under clean running water for 10 to 20 minutes, cover loosely and seek medical help for serious burns.
• Arc eye: Take the person to a dark, quiet place, do not let them rub their eyes, and seek medical attention.
• Fume overexposure: Move the person into fresh air and get medical help if breathing is affected.
• Fire: Dry powder or carbon dioxide extinguishers are suitable for fires involving electrical equipment.

Training and drills ensure that workers understand and can apply these procedures, and emergency contacts and first aid kits must be displayed and kept stocked.

Chapter Summary

This chapter provides a comprehensive guide to carrying out manual metal arc welding (MMAW) with a strong emphasis on occupational health and safety standards, including relevant workplace legislation, risk assessment, and incident management. It highlights the importance of workshop ergonomics, environmental safety, and waste management through proper housekeeping, sorting, and disposal practices. The interpretation of working drawings is covered with focus on dimensions, tolerances, and welding symbols to ensure accuracy in fabrication. Detailed descriptions of MMAW machines, tools, and materials are presented, covering different power sources, essential accessories, electrode types, and proper care and storage. Key welding parameters such as current, arc length, arc force, and polarity are explained for effective welding control. The chapter also addresses material preparation techniques for metals up to 16 mm thickness, including measuring, marking out, cutting, and edge preparation. Various welding positions and types of welded joints are discussed to accommodate different fabrication needs. Finally, common weld defects are identified with their causes and prevention methods, and finishing processes such as buffing, polishing, grinding, varnishing, and painting are described to enhance the quality and durability of welded products.