Workshop safety, health and environmental practice
Workshop safety, health and environmental practice is examined through hazard recognition, correct selection of protective and fire equipment, safe lifting, and legal disposal of workshop waste. Questions usually describe a situation and ask for the next safe action.
Hazards and controls
- Petrol, solvent and paint vapour form flammable atmospheres; ignition sources include grinding sparks, cigarettes and unguarded heaters.
- Carbon monoxide from a running engine is colourless and odourless. Never run an engine in a closed bay without extraction.
- Compressed air must not be used on skin or clothing; it can force air into tissue.
- Charging batteries releases hydrogen. Keep vents clear and flames away.
- Before working under a vehicle, support it on axle stands rated for the load. A trolley jack is a lifting device only.
Fire and spill response
Class A solids use water or foam; Class B flammable liquids use foam, CO2 or dry powder, never water; Class C gases and Class D metals need special media; Class F cooking oils use wet chemical. CO2 suits live electrical equipment because it leaves no residue, but it displaces oxygen in a pit.
Worked example. A 5 L engine-oil spill is absorbed at 1 kg per litre plus 50% contingency. Absorbent = 5 × 1.5 = 7.5 kg. Oil is Class B, so granules are spread from the outside in, and the used absorbent goes into a labelled hazardous-waste drum for a licensed recycler - not into general refuse or a drain.
Traps that cost marks
Water on burning petrol spreads the fire. Treating a trolley jack as a support. Pouring waste oil down a drain. Storing acid and solvents together. Ignoring a small leak that can reach a watercourse.