Workplace Safety, Health, and Environment (OHS) Compliance
This domain tests hazard recognition and control for GTAW in shop and field work: PPE, arc radiation, fumes, shielding-gas displacement, cylinder handling, electrical safety, hot work, and emergency response.
Core rules
- Complete a risk assessment and hot work permit before striking an arc; clear combustibles, assign a fire watch, and check ventilation.
- Wear a welding helmet with the correct filter, safety glasses underneath, flame-resistant clothing, leather gloves, apron, and safety shoes. Use respiratory protection when the assessment shows fume exposure.
- GTAW produces UV/IR radiation, ozone, nitrogen oxides, and metal fume. Argon and helium are not toxic but displace oxygen; confined spaces need atmospheric testing, continuous monitoring, ventilation, an attendant, and a rescue plan.
- Keep cylinders upright and secured, fit valve caps during transport, keep oil and grease away from oxygen, use correct regulators and flashback arrestors, leak-test with soap solution, and separate full and empty cylinders.
- Inspect torch leads and grounds; clamp the work return close to the weld; keep insulation dry; isolate and lock out equipment before repair.
Worked example
A welder must root-weld inside a tank using an argon purge. Argon is an asphyxiant, so the purge hose must vent outside, oxygen must be tested before entry and monitored continuously, mechanical ventilation must run, and an attendant with a rescue plan must stay at the entry. The hot work permit must cover confined-space entry. A dust mask does not protect against oxygen deficiency.
Traps that cost marks
- Saying argon is safe because it is inert.
- Treating the helmet as a substitute for safety glasses.
- Laying cylinders down or using oil on an oxygen regulator.
- Skipping a permit because the job is small.
- Entering a purged space without testing or monitoring.