Trade Safety, Occupational Health and Environment
This domain tests how well you recognise hazards in a sheet metal shop and apply controls before an injury occurs. Expect questions on PPE, machine guarding, fire fighting, electrical safety, housekeeping, waste disposal and occupational disease.
Core rules
- Select PPE by task: impact goggles for shearing, face shield for grinding, shade-10 or darker helmet for arc welding, ear plugs above roughly 85 dB(A), and cut-resistant gloves for handling sheet edges. Do not wear loose gloves near rotating spindles.
- Guards must remain on shears, presses, grinders and drills. Use lockout/tagout before blade change, roll adjustment or clearing a jam.
- The fire triangle is heat, fuel and oxygen. Remove any one side to extinguish. Water suits Class A solids; foam suits flammable liquids; CO2 or clean agent suits live electrical equipment; dry powder is general purpose; special dry powder is used on combustible metals.
- Keep aisles clear, store sheet vertically in racks, segregate metal scrap, oily rags and packaging, and provide local exhaust ventilation for welding, soldering and painting.
Worked example
A small fire starts inside an electrical control panel. The correct first action is to raise the alarm and isolate the supply if it is safe to do so. Do not use a water or foam extinguisher because water conducts electricity and foam leaves a conductive residue. Use CO2 or a clean-agent extinguisher, aiming at the base of the fire. If the panel cannot be isolated safely, evacuate. Reasoning: the fuel is energised electrical equipment, so the extinguishing agent must be non-conducting and leave no residue.
Traps that cost marks
Using water on electrical or oil fires; cleaning clothes with compressed air; removing a guard to speed up work; ignoring noise because hearing loss is gradual; and storing gas cylinders without chains or caps.