8.1 Welding Safety Hazards and Prevention
Key Takeaways
- Six major hazards: electric shock (most serious), fumes/gases, radiation, burns (most common), fire/explosion, confined spaces
- Burns are the most common injury; electric shock is the most serious immediate hazard
- Combustibles must be cleared 35 feet from welding; fire watch must remain 30 minutes after welding
- Confined spaces require atmospheric monitoring, forced ventilation, and a standby attendant
- Hexavalent chromium (stainless steel) causes lung cancer; zinc (galvanized) causes metal fume fever
- Filter lens shade numbers increase with welding current — know minimum requirements per process
8.1 Welding Safety Hazards and Prevention
Welding safety is a tested topic on Part A of the CWI exam. The welding inspector must understand the hazards present in welding operations to protect workers and ensure compliance with OSHA regulations and industry best practices.
Six Major Welding Hazards
1. Electric Shock
Electric shock is the most serious immediate hazard in welding — it can cause death.
| Type | Voltage Range | Risk Level |
|---|---|---|
| Primary voltage shock | 230–460V (power source input) | Extremely dangerous — can be fatal |
| Secondary voltage shock | 20–100V (welding circuit) | Dangerous, especially in wet or confined conditions |
Prevention:
- Never touch electrode or wire with bare skin or wet gloves
- Ensure all equipment is properly grounded
- Keep cables and connections in good repair (no bare spots)
- Do not stand or lie in water while welding
- Use insulated electrode holders and work clamps
- Turn off equipment when not in use
2. Fumes and Gases
Welding fumes are a complex mixture of metallic oxides, silicates, and fluorides that are generated during welding. Prolonged exposure can cause serious respiratory illness.
Particularly hazardous fumes:
| Material | Hazard |
|---|---|
| Hexavalent chromium (Cr⁶⁺) | Lung cancer — generated when welding stainless steel or chromium alloys |
| Manganese | Neurological damage (manganism) — present in many electrodes and wire |
| Zinc | Metal fume fever (from galvanized steel) — flu-like symptoms |
| Cadmium | Extremely toxic — can be fatal; found in some plated/coated metals |
| Lead | Lead poisoning — found in some paints and coatings |
| Beryllium | Lung disease — found in some copper alloys |
Control hierarchy (most effective first):
- Elimination/substitution — use low-fume processes, low-fume electrodes
- Engineering controls — local exhaust ventilation (LEV), general ventilation
- Administrative controls — limit exposure time, rotate workers
- PPE (last resort) — respiratory protection (N95, half-face, PAPR)
3. Radiation (Arc Ray Hazards)
| Type | Hazard | Protection |
|---|---|---|
| Ultraviolet (UV) | Arc eye/welder's flash (photokeratitis), skin burns similar to sunburn | Welding helmet with proper shade filter lens, clothing coverage |
| Infrared (IR) | Retinal damage, cataracts from prolonged exposure | Proper filter lens, safety glasses with IR protection |
| Visible light | Temporary vision impairment | Auto-darkening or fixed-shade helmet |
Minimum Filter Lens Shade Numbers (OSHA/ANSI Z87.1):
| Process | Current Range | Minimum Shade |
|---|---|---|
| SMAW | 60–160A | 10 |
| SMAW | 160–250A | 12 |
| SMAW | 250–550A | 14 |
| GMAW/FCAW | 60–160A | 10 |
| GMAW/FCAW | 160–250A | 10 |
| GMAW/FCAW | 250–500A | 12 |
| GTAW | < 50A | 8 |
| GTAW | 50–150A | 10 |
| GTAW | 150–500A | 12 |
| PAC | < 300A | 8 |
| PAC | 300–400A | 10 |
| OFC | Light cutting | 3–5 |
4. Burns
Burns are the most common welding injury:
- Arc burns from UV radiation (similar to severe sunburn)
- Contact burns from hot metal, spatter, slag
- Flash burns to eyes from UV exposure without proper protection
Prevention: Wear fire-resistant clothing covering all exposed skin; leather gloves; steel-toed boots; no cuffed pants or open pockets that can catch spatter.
5. Fire and Explosion
- Keep a Class ABC fire extinguisher within reach at all times
- Clear combustible materials within 35 feet (10 m) of welding operations
- Hot work permit required when welding outside designated welding areas
- Fire watch — a person designated to watch for fires during and for 30 minutes (minimum) after welding
6. Confined Space Hazards
Welding in confined spaces (tanks, vessels, pits) presents additional hazards:
- Oxygen depletion — shielding gases displace oxygen; monitor atmosphere continuously
- Toxic fume accumulation — fumes concentrate in enclosed spaces
- Electric shock risk — increased in damp, enclosed environments
Confined space requirements:
- Continuous atmospheric monitoring (O₂, LEL, toxic gases)
- Forced ventilation
- Entry/exit procedures and rescue plan
- Attendant stationed outside at all times
- Low-voltage welding equipment preferred
For the Exam: Know the six major hazards, the filter lens shade requirements, the 35-foot clearance for combustibles, and the 30-minute fire watch requirement. Electric shock is the most serious immediate hazard; burns are the most common injury.
What is the most common welding injury?
After welding outside a designated welding area, a fire watch must remain for at least:
Combustible materials must be cleared from welding operations for a distance of at least:
Welding on galvanized steel produces fumes of which hazardous material?