Workplace Safety, Health, and Housekeeping for GMAW
Domain 1 - Workplace safety, health, and housekeeping. This domain tests whether you can run a GMAW station without injuring yourself or others, control fume and shielding-gas hazards, and keep the area to 5S standards.
Control order
Eliminate or substitute first, then engineer the hazard out (local exhaust ventilation, screens, barriers), then administrative controls (hot work permit, fire watch), and PPE last. PPE protects only the wearer and never replaces ventilation.
PPE
- Helmet with the right filter shade: GMAW at 100–200 A generally needs shade 11–12 (range 10–13 by current).
- Safety glasses under the helmet and when grinding; face shield for grinding.
- Leather gauntlet gloves, flame-resistant sleeves or apron, leather boots, hearing protection.
- Respirator (P100 or supplied air) where ventilation is inadequate.
Fume and gas
GMAW fume is fine and respirable: keep your head out of the plume, weld so the plume rises away from your breathing zone, and use LEV or a ventilated booth. Argon and CO2 are asphyxiants - argon is heavier than air and pools in pits, so never weld in a confined space without atmosphere testing and a standby person. Secure cylinders upright with a chain and keep oil and grease off valves and fittings. Chlorinated degreasers struck by arc radiation can form phosgene, so clean and let the part dry first.
5S and fire
Sort, set in order, shine, standardize, sustain. Keep leads off walkways, clear combustibles 11 m (35 ft) from the arc, use a hot work permit and fire watch, and clamp the ground to clean metal.
Worked example: A welder works in a closed room with an unchained argon cylinder and a solvent-soaked rag nearby. Hazards: oxygen displacement, cylinder tip-over, fume exposure, phosgene. Controls: ventilate or add LEV, chain the cylinder upright outside the work zone, remove the rag and let the part dry, post a fire watch, wear the correct shade and respirator.
Traps: assuming GMAW makes no fume because it makes no slag; leaving a cylinder unchained just for a minute; using compressed air to blow fume from your face.