Health, Safety and Environmental Protection
This domain tests hazard identification and exposure control for arc welding, cutting and allied processes.
Fume and gases
Welding fume contains metal oxides and can include hexavalent chromium and nickel from stainless consumables, manganese, and fluorides from basic electrodes. Exposure is assessed by personal sampling to standards such as EN ISO 10882-1 (particulate) and -2 (gases). Controls follow the hierarchy: elimination, substitution, engineering controls such as local exhaust ventilation (LEV) and extraction torches, then administrative controls, then respiratory protective equipment. Confined spaces require gas testing and a permit before entry; argon and CO₂ displace oxygen and cause asphyxiation.
Physical hazards
Arc radiation causes arc eye (photokeratitis) and skin burns; appropriate filter shades differ for arc welding, gas welding and gouging. Electric shock risk rises with damp conditions, damaged cables and open-circuit voltage; equipment must be inspected and earthed. Fire watch is needed where sparks can reach combustibles. Noise from gouging and plasma cutting may exceed action levels.
Worked example
A welder is exposed to 0.10 mg/m³ manganese for 4 hours and 0.02 mg/m³ for the other 4 hours. 8-hour TWA = (0.10×4 + 0.02×4)/8 = 0.06 mg/m³. If the workplace exposure limit is 0.05 mg/m³, exposure exceeds the limit and LEV or RPE must be improved. Reasoning: time-weighted averaging weights each concentration by its duration.
Traps
Assuming general ventilation is adequate for stainless or confined-space work. Using the wrong filter shade for the process. Overlooking that shielding gases are asphyxiants. Treating PPE as the first control rather than the last.