Lesson Notes By Weeks and Term v3 - Senior Secondary 2
Safety facilities and protective wears
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Safety facilities and protective wears
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Subject: Welding & Fabrication
Class: Senior Secondary 2
Term: 1st Term
Week: 1
Theme: Workshop And Standard Workshop Practices
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identify and observe standard workshop safety rules and regulations identify the protective wears for:• welding• fabrication
for welding, but especially crucial for protection against falling tools, heavy components, and crushing injuries during material movement.
5. Overalls/Work Uniform: Purpose: Protects personal clothing and skin from dirt, minor cuts, and sparks. Should be durable, comfortable, and fit well to avoid snagging.
Characteristics: Made of durable cotton or polycotton blends.
6. Ear Protection: Purpose: Essential when operating noisy machinery like angle grinders, plasma cutters, power saws, or hydraulic presses.
Types: Earplugs or earmuffs.
7. Dust Masks/Respirators: Purpose: Protects against inhaling dust generated from grinding, sanding, or cutting certain materials. Also for fumes during cutting processes.
Types: Similar to those for welding, chosen based on the specific airborne hazard.
8. Face Shields: Purpose: Provides full-face protection against flying particles, sparks, chemical splashes, and light impact. Worn over safety glasses.
When to use: For grinding, chipping, abrasive cutting, and using power tools that generate significant debris.
Worked Example for PPE Selection: Scenario: A welder needs to perform arc welding on a mild steel plate, and subsequently grind off excess material.
PPE Selection:
1. Arc Welding: Welding Helmet (Auto-darkening): To protect eyes and face from intense light, UV/IR radiation, and spatter.
Welding Gloves (Leather gauntlet type): To protect hands from heat, sparks, and electrical shock. Flame-retardant Overalls/Jacket and Trousers: To protect the body from burns and sparks.
Safety Boots (Steel-toe): To protect feet from falling objects and hot metal.
Safety Glasses (under helmet): For primary eye protection when helmet is lifted. Respirator (e.g., N95): If welding in an enclosed space or on coated metals, to protect from fumes.
2. Grinding: Face Shield (worn over safety glasses): For full-face protection against high-velocity flying sparks and metal particles.
Safety Glasses (impact-resistant): Essential primary eye protection. Work Gloves (e.g., heavy-duty leather or cut-resistant): To protect hands from abrasions and heat from sparks.
Overalls/Work Uniform: To protect clothing and skin from sparks and dust.
Safety Boots (Steel-toe): For foot protection.
Ear Protection (earplugs/muffs): To protect against the high noise levels generated by the grinder. * Dust Mask (N95): To protect lungs from inhaling metal dust. This section provides in-depth explanations of safety facilities, protective wears, and relevant workshop safety rules and regulations. 2.1 Introduction to Workshop Safety Workshop safety refers to the practices and measures taken to prevent accidents, injuries, and health hazards in a workshop environment. In welding and fabrication, hazards are numerous, including: Extreme Heat and Sparks: From welding arcs, molten metal, and grinding operations.
Intense Light and Radiation: UV and infrared radiation from welding arcs can cause 'arc eye' (photokeratitis) and skin burns.
Toxic Fumes and Gases: Generated during welding, cutting, and grinding of various metals and coatings.
Sharp Objects and Edges: Raw materials, cut metal pieces, and tools.
Heavy Materials and Equipment: Lifting and moving heavy plates, beams, and machinery.
Electrical Hazards: From welding machines, power tools, and faulty wiring.
Noise Pollution: From grinders, plasma cutters, and hammering. 2.2 Standard Workshop Safety Rules and Regulations Adherence to these rules is paramount for maintaining a safe working environment.
A. General Workshop Safety Rules (Applicable to both Welding and Fabrication):
1. Maintain a Clean and Organized Workspace: Keep floors free of spills, tools, and scrap materials to prevent slips, trips, and falls. Good housekeeping is fundamental.
2. No Horseplay or Running: Workshop environments are dangerous; playful activities can lead to serious accidents.
3. Use Tools Correctly: Always use the right tool for the job, and ensure tools are in good working condition. Never use damaged or faulty tools.
4. Report All Accidents and Incidents: Even minor cuts or near-misses should be reported to the supervisor immediately to prevent recurrence and ensure proper first aid.
5. Know Emergency Procedures: Be aware of the location of fire extinguishers, first aid kits, emergency exits, and who to contact in an emergency.
6. Avoid Distractions: Focus on the task at hand. Avoid using mobile phones or engaging in conversations that divert attention.
7. Do Not Work Alone: Especially when performing hazardous tasks. Ensure someone is aware of your activity.
8. Tag Out/Lock Out Procedures: For machine maintenance, ensure power is disconnected and locked out to prevent accidental startup.
9. Proper Ventilation: Ensure adequate air circulation to dissipate fumes and heat.
B. Specific Welding Safety Rules:
1. Fire Prevention: Clear away all flammable materials (paper, wood, oil rags) from the welding area. Have a fire extinguisher or fire blanket readily available. Inspect hoses and cables for damage before use. Be aware of hot metal surfaces and flying sparks; they can ignite materials hours later.
2. Electrical Safety: Ensure welding machine and cables are properly insulated and grounded. Do not weld in wet conditions or with wet gloves. Inspect electrode holders and ground clamps for proper insulation.
3. Cylinder Handling: Secure gas cylinders upright with chains or straps to prevent tipping. Store oxygen and fuel gas cylinders separately. Handle regulators and valves with care.
4. Ventilation for Fumes: Always weld in a well-ventilated area or use local exhaust ventilation (fume extractors) to remove harmful fumes and gases. Avoid welding galvanized steel, lead-painted metals, or cadmium-plated metals without specialized ventilation or respirators.
C. Specific Fabrication Safety Rules:
1. Machine Guarding: Ensure all moving parts of machinery (e.g., grinders, presses, shears) have appropriate guards in place. Never remove safety guards or bypass safety interlocks.
2. Material Handling: Use proper lifting techniques or mechanical aids (cranes, forklifts) when moving heavy materials. Wear appropriate gloves when handling sharp-edged materials. Stack materials safely to prevent collapses.
3. Cutting Tools: Ensure blades on cutting machines (e.g., hacksaws, bandsaws, angle grinders) are sharp and correctly installed. Keep hands clear of cutting paths.
4. Compressed Air: Never direct compressed air towards yourself or others; it can cause serious injury. Use appropriate nozzles and regulate pressure. 2.3 Protective Wears (Personal Protective Equipment - PPE) PPE are devices or clothing designed to protect individuals from hazards in the workplace.
A. Protective Wears for Welding: Welding involves intense heat, light, sparks, and fumes, requiring specialized PPE.
1. Welding Helmet/Face Shield: * Purpose: Protects eyes and face from intense UV/infrared radiation, sparks, spatter, and heat. are sharp and correctly installed. Keep hands clear of cutting paths.
4. Compressed Air: Never direct compressed air towards yourself or others; it can cause serious injury. Use appropriate nozzles and regulate pressure. 2.3 Protective Wears (Personal Protective Equipment - PPE) PPE are devices or clothing designed to protect individuals from hazards in the workplace.
A. Protective Wears for Welding: Welding involves intense heat, light, sparks, and fumes, requiring specialized PPE.
1. Welding Helmet/Face Shield: Purpose: Protects eyes and face from intense UV/infrared radiation, sparks, spatter, and heat.
Types: Fixed Shade: Requires flipping up to see before striking an arc. Shades range from 9-14 depending on welding process and current.
Auto-Darkening: Automatically darkens to a pre-set shade (e.g., Shade 10-13) within milliseconds of an arc strike, allowing continuous vision. More convenient but generally more expensive.
Nigerian Context: Common in most workshops, often shared or personally owned. Importance of proper shade selection for specific welding processes (e.g., SMAW, GTAW, GMAW).
2. Welding Gloves: Purpose: Protect hands and wrists from heat, sparks, molten metal, UV radiation, and cuts.
Characteristics: Usually made of thick leather (e.g., cowhide, deerskin), gauntlet-style (long cuff) to protect wrists. Different types for different welding processes (e.g., thicker gloves for stick welding, thinner for TIG welding for dexterity).
3. Flame-Retardant Clothing: Purpose: Protects the body from sparks, spatter, and radiant heat.
Types: Heavy-duty cotton or denim overalls, leather aprons, leather jackets, or sleeves. Synthetic materials (nylon, polyester) should be avoided as they melt and can cause severe burns.
Nigerian Context: Often, workers use thick denim jeans and shirts. Leather aprons are crucial for additional protection, especially for tasks like overhead welding.
4. Safety Boots/Shoes: Purpose: Protect feet from falling objects, crushing hazards, electrical shock, and heat.
Characteristics: Must be sturdy leather, slip-resistant, and have steel toe caps and often steel midsoles.
5. Safety Glasses/Goggles: Purpose: Worn under the welding helmet or face shield to provide primary eye protection when the helmet is lifted or during grinding/chipping nearby.
Characteristics: Impact-resistant lenses (e.g., polycarbonate).
6. Respirators/Face Masks: Purpose: Protect the respiratory system from inhaling hazardous fumes, gases, and particulate matter generated during welding.
Types: Nuisance dust masks: For light dust. Filtering facepiece respirators (e.g., N95, P100): For fine particles and some fumes.
Powered Air-Purifying Respirators (PAPRs): Provide filtered air, offering higher protection and comfort.
Nigerian Context: Often overlooked in smaller workshops due to cost or lack of awareness, but essential for health.
7. Ear Protection: Purpose: Protects hearing from excessive noise produced by arc air gouging, plasma cutting, or grinding operations.
Types: Earplugs or earmuffs.
B. Protective Wears for Fabrication: Fabrication involves cutting, grinding, shaping, and assembly, with hazards like sharp edges, flying particles, heavy impacts, and noise.
1. Safety Glasses/Goggles: Purpose: Primary eye protection against flying debris, sparks, and chemical splashes.
Characteristics: Impact-resistant, often with side shields.
2. Safety Gloves: Purpose: Protect hands from cuts, abrasions, punctures, and chemical exposure.
Types: Leather gloves: For general material handling, light welding, and protection against minor cuts.
Cut-resistant gloves: For handling sharp metal sheets or edges.
Impact gloves: For tasks involving hammering or heavy material handling.
Nitrile or chemical-resistant gloves: For handling chemicals, oils, or solvents.
3. Hard Hat: Purpose: Protects the head from falling objects, impacts, and electrical hazards (if dielectric).
When to use: Required in areas where there's a risk of falling objects, overhead work, or near cranes/lifting equipment.
4. Safety Boots/Shoes: Purpose: As described for welding, but especially crucial for protection against falling tools, heavy components, and crushing injuries during material movement.
5. Overalls/Work Uniform: Purpose: Protects personal clothing and skin from dirt, minor cuts, and sparks. Should be durable, comfortable, and fit well to avoid snagging.
Characteristics: Made of durable cotton or polycotton blends.
6. Ear Protection: Purpose: Essential when operating noisy machinery like angle grinders, plasma cutters, power saws, or hydraulic presses.
Types: Earplugs or earmuffs.
7. Dust Masks/Respirators: * Purpose: Protects against inhaling dust generated from grinding, sanding, or Teacher Activities: Introduction (10 mins): Begin by asking students to share any experiences or knowledge about workshop hazards or accidents they might have heard of in Nigerian communities (e.g., during apprenticeship, from family members). Lead a brief discussion on the importance of safety in any technical field.
Presentation of Safety Rules (20 mins): Present the general, welding-specific, and fabrication-specific safety rules using charts, projected slides, or by writing on the board. Explain each rule clearly, emphasizing the 'why' behind it (e.g., "Why no horseplay?" - risk of collision, falls, contact with machinery). Use examples relevant to typical Nigerian workshops (e.g., fire hazards from oil spills, dangers of unchained gas cylinders). Introduction and Demonstration of Protective Wears (30 mins): Display various PPE items for both welding and fabrication (if available). If not, use clear pictures/diagrams. Introduce each item (e.g., "This is a welding helmet"). Demonstrate the correct way to wear and adjust each piece of PPE (e.g., fitting a helmet, adjusting shade, wearing gloves, tying an apron). Explain the specific hazards each PPE item protects against and when it should be used. Emphasize the importance of inspecting PPE before use for damage.
Interactive Discussion and Q&A (15 mins): Encourage students to ask questions about safety rules and PPE. Pose scenarios for students to identify appropriate PPE or safety rules (e.g., "What PPE would you wear if you were using a grinding machine?"). Group Activity - Safety Poster/Scenario Analysis (30 mins): Divide students into small groups (3-4 per group). Assign each group a specific welding or fabrication task (e.g., "SMAW welding of a gate frame," "Cutting metal sheets with an angle grinder," "Moving heavy metal beams").
Instruct groups to: List 3-5 potential hazards for their assigned task. Identify 3-5 relevant safety rules to observe. List the necessary protective wears. Teacher circulates, guides groups, and clarifies misconceptions.
Review and Conclusion (5 mins): Summarize key takeaways on safety rules and protective wears. Emphasize that safety is everyone's responsibility.
Student Activities: Actively participate in class discussions about workshop hazards. Take notes on standard safety rules and regulations. Observe the teacher's demonstration of protective wears and ask clarifying questions. In groups, identify hazards, list safety rules, and determine appropriate PPE for assigned welding/fabrication scenarios. Present group findings to the class. Practically demonstrate wearing and adjusting various PPE items as requested by the teacher.
Ensuring Safety in Local Fabricator Workshops: Many informal welding and fabrication workshops exist across Nigeria (e.g., small-scale metal furniture production in Lagos, gate fabrication in Kaduna). Integrating this topic allows students to identify unsafe practices common in these local settings (e.g., lack of proper ventilation, absence of helmets, wearing sandals) and advocate for or implement safer working habits, thereby reducing occupational hazards prevalent in the informal sector.
Employability in Industrial Clusters: In industrial zones like those in Port Harcourt (oil & gas fabrication), Aba (general manufacturing), or Ogun State (heavy industries), strict adherence to safety protocols and proper PPE use is a mandatory requirement for employment. This lesson directly equips students with essential knowledge that makes them more desirable and competent candidates for formal sector jobs, reducing the risk of workplace accidents that can lead to loss of income or permanent disability.
Community Safety Advocacy: Students can apply this knowledge by educating family members, friends, or local artisans about basic workshop safety. They can help identify potential hazards in community-based projects (e.g., school gate repairs, construction work) and suggest appropriate safety measures, fostering a culture of safety consciousness beyond the classroom. For example, advising a local artisan on the need for a face shield when grinding or the importance of proper footwear.