Abrasive Wheels Training Certificate Guarding Requirements 2 — Questions and Answers
Question 1: What standard covers the design and testing of guards for portable grinding machines in the UK?
- BS EN 60745 (for handheld motor-operated tools) and BS EN 12413 (for abrasive wheels) (Correct answer)
- BS EN 50144 only
- Only national guidance documents — no specific standard applies
- PUWER 1998 is the only relevant document
Correct answer: BS EN 60745 (for handheld motor-operated tools) and BS EN 12413 (for abrasive wheels)
BS EN 60745 is the harmonised standard for handheld motor-operated tools including angle grinders, specifying guard design, dimensions, and testing. BS EN 12413 covers the abrasive product itself. Both are relevant to angle grinder safety — the machine and wheel must each comply with their respective standards.
Question 2: What does a 'dead man's switch' (hold-to-run control) provide on angle grinders?
- The grinder stops immediately when the operator releases the trigger, preventing continued rotation if the tool is dropped or control is lost (Correct answer)
- A deadlock preventing the trigger being accidentally depressed
- An automatic speed controller that prevents overspeed
- A switch that disables the machine when excessive vibration is detected
Correct answer: The grinder stops immediately when the operator releases the trigger, preventing continued rotation if the tool is dropped or control is lost
A hold-to-run (dead man's switch) trigger ensures the angle grinder stops immediately when the operator releases grip, for example if they trip, lose control, or are injured. This prevents a dropped spinning grinder from continuing to rotate uncontrolled, reducing contact injury risk. PUWER requires controls that are safe in foreseeable fault conditions.
Question 3: What additional guarding is required when angle grinding near pedestrians or other workers?
- A spark containment screen or fire blanket placed between the grinding area and other workers, plus warning signs and exclusion zone (Correct answer)
- The angle grinder guard alone provides adequate protection for nearby workers
- Only hearing protection for nearby workers — sparks are not a hazard at 2 metres distance
- No additional guarding is required if the other workers are wearing high-visibility vests
Correct answer: A spark containment screen or fire blanket placed between the grinding area and other workers, plus warning signs and exclusion zone
Grinding sparks can travel 3–10 metres. Workers in the vicinity must be protected by spark containment screens or fire blankets. An exclusion zone must be established around grinding operations and marked with warning signs. Only authorised workers wearing appropriate PPE should be within the exclusion zone.
Question 4: What is the purpose of the supplementary side handle on an angle grinder?
- To provide a two-handed grip, improving control and reducing the risk of the tool being pulled out of control by reaction torque or snatch (Correct answer)
- To allow the tool to be suspended from a hook when not in use
- To provide a mounting point for a secondary guard
- To house the vibration dampening system
Correct answer: To provide a two-handed grip, improving control and reducing the risk of the tool being pulled out of control by reaction torque or snatch
The supplementary handle allows the operator to control the angle grinder with both hands, providing better control against reaction torque, kickback, and tool snatch. Two-handed operation also keeps the operator's body in a more controlled, balanced position. Using an angle grinder with one hand increases the risk of losing control.
Question 5: What must be inspected on angle grinder guards before each use?
- Check for cracks, bending, or deformation (which would indicate previous disc burst), check all fixing points are secure, and confirm the guard is correctly positioned and adjusted (Correct answer)
- Only check that the guard is present — condition does not need to be assessed daily
- Guards only need inspection at annual service intervals
- Check that the guard does not contact the disc when the machine is switched on
Correct answer: Check for cracks, bending, or deformation (which would indicate previous disc burst), check all fixing points are secure, and confirm the guard is correctly positioned and adjusted
Guards must be inspected before each use: cracks, bends, or deformation indicate the guard has already been stressed by a disc burst and may not provide adequate protection in a further incident. Loose fixings could allow the guard to shift during use. A damaged or deformed guard must be replaced before the machine is used.
Question 6: What is a 'two-stage switch' on an angle grinder and why is it required?
- A switch that requires deliberate actuation in two steps (e.g., squeeze lock-off then pull trigger) to prevent accidental starting, as required by BS EN 60745 (Correct answer)
- A switch with both on and off positions requiring equal force to operate
- A speed-selection switch between two operating speeds
- A switch requiring two people to operate — used only in industrial applications
Correct answer: A switch that requires deliberate actuation in two steps (e.g., squeeze lock-off then pull trigger) to prevent accidental starting, as required by BS EN 60745
A two-stage switch (anti-restart/anti-inadvertent-start switch) requires a deliberate two-step action to start the machine — typically pressing a safety lock-off button before squeezing the trigger. This prevents accidental starting if the machine is dropped, picked up with a hand on the trigger, or has a faulty trigger spring.
Abrasive Wheels Training Certificate Guarding Requirements 2
What standard covers the design and testing of guards for portable grinding machines in the UK?