Abrasive Wheels Training Certificate Hazards of Abrasive Wheels

Question 1

What is the primary cause of abrasive wheel burst, which is the most serious hazard?

Accepted Answer

Overspeed — operating the wheel above its maximum RPM rating causes centrifugal forces to exceed the bond's tensile strength

Answer

Excessive downward pressure on the wheel during grinding

Answer

Coolant contamination of the grinding wheel bond

Answer

Running the wheel in the wrong direction of rotation

Question 2

What energy does a bursting abrasive wheel release, and why is this so dangerous?

Accepted Answer

Kinetic energy proportional to mass and the square of peripheral velocity; fragments can travel at several hundred metres per second

Answer

Only thermal energy from friction — fragments are too light to cause serious injury

Answer

Potential energy only if the wheel is mounted at height

Answer

Chemical energy from the abrasive reaction with the workpiece

Question 3

What is the hazard of 'contact' with an abrasive wheel?

Accepted Answer

Severe laceration, degloving, or amputation from accidental contact with the rotating abrasive surface

Answer

Only superficial skin abrasion in brief contact

Answer

Burns from the grinding sparks rather than the wheel surface

Answer

Only a hazard during wheel mounting, not during operation

Question 4

What type of vibration hazard is associated with extended use of angle grinders?

Accepted Answer

Hand-arm vibration syndrome (HAVS) causing permanent damage to blood vessels, nerves, and joints in the hands and arms

Answer

Only acute fatigue with no long-term effects

Answer

Only affects workers over 60 years of age

Answer

Vibration only causes short-term numbness that resolves within 24 hours

Question 5

What fire and explosion hazard is created by grinding sparks?

Accepted Answer

Sparks can travel several metres and ignite flammable materials, liquids, vapours, and combustible dusts in the vicinity

Answer

Sparks only ignite materials that are directly adjacent to the grinding operation

Answer

Sparks from abrasive grinding are too low temperature to ignite materials other than paper

Answer

Only dry wood is at risk of ignition from grinding sparks

Question 6

What health hazard is caused by inhaling grinding dust and fume?

Accepted Answer

Respiratory diseases including occupational asthma, fibrosis, and metal fume fever depending on the workpiece material

Answer

Only temporary irritation with no long-term health effects

Answer

Hazard is limited to workers with pre-existing asthma

Answer

Only a hazard when grinding stainless steel — mild steel presents no risk