Safety, Health and Environment for Arc Welding
The hazard set
SMAW concentrates electric shock, arc radiation, fume, fire and noise in one operation. Open-circuit voltage is commonly 50-80 V - low by industrial standards but lethal in wet conditions. Inspect the electrode holder and cable jacket every shift, never change polarity or cable connections with the machine energised, and never weld in a wet pit or on damp ground without an isolating device and dry insulation.
Arc radiation burns both eyes and skin. Select filter shade by current and electrode size: roughly shade 10 for thin electrodes at low current, shade 11 around 150 A, shade 12 for 6 mm electrodes at 250-300 A. Wear safety glasses under the helmet when chipping slag, and cover the throat and forearms - UV passes thin fabric.
Fume control matters more than most candidates expect. Stainless electrodes generate hexavalent chromium, galvanised steel gives zinc fume, cellulosic coatings produce heavy particulate. Use local exhaust or a supplied-air respirator in confined spaces and keep your head out of the plume.
Hot work control: permit, an 11 m combustible-free radius, a fire watch, and a 30-minute watch after the last arc. Oxygen and fuel-gas cylinders are separated by 6 m or a 30-minute fire-rated barrier, secured upright, valves capped during movement.
Worked example: 4 mm E7018 at 180 A, overhead, shop bay
Shade 11 helmet; leather jacket, gauntlets, apron, spats; local exhaust drawing the plume away from the breathing zone; hearing protection if grinding is nearby; hot work permit with a 30-minute fire watch; confirm no solvent degreasing is running in the bay, because arc UV on chlorinated vapour produces phosgene.
Traps that cost marks
- Judging ventilation by smell - fume is often invisible at low concentration.
- Treating leather gauntlets as waterproof; wet leather conducts.
- Assuming E7018 only needs to be "kept indoors" rather than in a holding oven.