Occupational Health, Safety and Environmental Protection in the Welding Workplace
This domain tests whether you can identify FCAW hazards, pick controls in the right order, and apply the specific numbers (lens shade, clearance distance, fire-watch time) that examiners use as discriminators. Environmental questions focus on fume, waste segregation and consumable disposal rather than general green-office ideas.
The FCAW hazard profile
FCAW deposits metal quickly and generates more fume than SMAW at the same amperage because of the flux core and high current density. The plume carries iron oxide and manganese, and with stainless or certain flux formulations, hexavalent chromium and nickel. UV radiation converts atmospheric oxygen to ozone. At 200–300 A the arc requires an 11–13 shade filter lens.
Control selection
Work the hierarchy: eliminate or substitute, then engineer the control (local exhaust ventilation, extraction torch, booths, flash screens), then administrative controls (hot work permit, rotation, training), and only then PPE such as a powered air-purifying respirator. Roof fans are dilution ventilation, not capture.
Fire, electricity and cylinders
Hot work permit before the first arc; combustibles cleared or protected within 10 m (35 ft); fire watch maintained during work and for at least 30 minutes after the last arc. Work return clamp on clean bare metal close to the joint. Cylinders upright and chained, valve cap on during transport, no oil or grease on oxygen fittings.
Worked example
A welder runs 280 A FCAW in a bay with roof exhaust only. Select controls and justify. Answer: shade 12 lens, local exhaust placed at the arc, plus a P2/P100 respirator if visible fume or sampling shows extraction is inadequate. Reasoning: lens shade follows current, and capture must happen at the source because general ventilation cannot remove the plume from the breathing zone before the welder inhales it.
Traps that cost marks
Choosing an over-dark lens, then lifting the hood to inspect the bead - that causes photokeratitis. Calling roof fans fume control. Ending the fire watch when the arc stops. Using compressed air on skin or clothing.