Workshop Safety, Tools and Equipment
Workshop Safety
Hazard control first
Workshop safety is the systematic control of hazards before they injure people or damage equipment. A candidate must understand PPE selection (goggles, gloves, safety footwear, hearing and respiratory protection), the fire triangle, extinguisher classes, safe fuel and solvent handling, correct jacking and lifting, battery hazards, exhaust gas, and electrical safety. Fuel fires are Class B and need foam, dry powder or CO2, never water. Electrical fires need CO2 or dry powder. A vehicle battery can produce explosive hydrogen and contains sulphuric acid, so disconnect the earth terminal first and never create sparks nearby.
Traps in questions
Common traps include jacking under a sill or floor pan instead of a designated jacking point, relying on a jack without axle stands, removing a radiator cap while the engine is hot, and assuming a 12 V battery is harmless. Another trap is poor ventilation: carbon monoxide from exhaust is colourless and odourless, so dizziness in a closed bay is an emergency, not a minor complaint. Also remember that compressed air is not for cleaning skin, and that a fire blanket smothers a person whose clothing is alight.
Rule of thumb
Chock the wheels, use stands rated above the vehicle load, and keep a clear escape route. If a fuel spill occurs, stop ignition sources, ventilate, contain with absorbent material, and dispose of it correctly.
Worked example: a technician feels dizzy while an engine runs in a closed workshop. The likely cause is carbon monoxide; switch off the engine, move the person to fresh air, and call for medical help.
Tools and Equipment
Choosing and using tools
Candidates must recognise hand tools, measuring tools, and special service tools, and know their safe use. Spanners must fit the fastener flats exactly; an open-ended spanner is for light torque, a ring spanner for higher torque, and a socket with a breaker bar for stubborn fixings. A torque wrench measures turning effort, not power, and must be calibrated. Micrometers, vernier calipers, feeler gauges, dial indicators, and Plastigauge are precision instruments: clean them, check zero, and read the scale carefully. Pullers and presses remove bearings without shock loads; a hammer should not be used on precision surfaces.
Traps in questions
A frequent trap is using an extension bar on a torque wrench and assuming the setting remains correct. A straight extension along the axis does not change torque, but an adapter that changes the lever length does. Another trap is confusing micrometer sleeve and thimble readings, or reading a vernier scale from the wrong edge. Questions also test that a feeler gauge measures a gap by drag, not by force, and that a dial indicator must be mounted rigidly. Never use a torque wrench to loosen fasteners.
Rule of thumb
Torque equals force multiplied by distance from the pivot, so a longer wrench needs less force. For a torque wrench with a lever-changing adapter, recalculate rather than guess.
Worked example: a wrench set to 100 N·m is fitted with a 50 mm adapter that increases effective length by 10%. The applied torque rises above the setting; the wrench must be reset to a lower value or the adapter avoided.