Abrasive Wheels Training Certificate Guarding Requirements

Question 1

What does PUWER 1998 Regulation 11 require regarding guards on abrasive wheel machines?

Accepted Answer

Guards must be provided and maintained that enclose the wheel as much as possible consistent with normal operation, and must be strong enough to retain fragments in the event of wheel burst

Answer

PUWER Regulation 11 requires that dangerous parts of machinery — including rotating abrasive wheels — are guarded by fixed or adjustable guards. For abrasive wheels, the guard must enclose the maximum practicable portion of the wheel, provide structural protection against wheel burst fragments, and comply with relevant British Standards.

Question 2

What is the maximum angle of exposure permitted for the grinding face of a bench grinder wheel?

Accepted Answer

Maximum 90 degrees of wheel exposure above the work rest (the remaining arc must be enclosed by the guard)

Answer

For bench grinders, the guard must enclose the wheel except for the necessary working area. BS 4481 specifies that the grinding exposure (the arc of wheel open to the work) should not exceed 90 degrees above the horizontal plane of the work rest. This minimises the arc of wheel exposed to the operator.

Question 3

What is the maximum permitted angle of wheel exposure for a portable angle grinder guard?

Accepted Answer

180 degrees — the guard must cover at least the upper half of the disc to deflect fragments away from the operator

Answer

For angle grinders, BS EN 60745 and PUWER require the guard to cover at least 180 degrees of the disc (the upper half facing the operator). The lower 180 degrees is the working sector. The 180-degree guard deflects fragments from wheel burst away from the operator and prevents hand contact with the upper disc face.

Question 4

What action must be taken if the adjustable guard on a bench grinder cannot be positioned within 3mm of the wheel face?

Accepted Answer

The wheel has worn too small and must be replaced — do not continue using the machine with an inadequate guard-to-wheel gap

Answer

As a grinding wheel wears, the guard must be adjusted to maintain the correct clearance. If adjustment is no longer possible because the wheel has worn to minimum usable size, the wheel must be replaced. Using a wheel that has worn beyond the point where the guard can be properly adjusted compromises both burst protection and contact prevention.

Question 5

A worker removes the guard from an angle grinder claiming it is needed to access a confined area. What is the correct response?

Accepted Answer

Work must stop — the guard must not be removed; if the area is inaccessible with the guard, an alternative tool or method must be found

Answer

Removing a guard from an angle grinder is prohibited under PUWER 1998 and is a serious criminal offence. If access is the issue, the correct solution is to select a smaller angle grinder with guard, or use an alternative tool. Access difficulties do not justify accepting the catastrophic consequences of unguarded disc burst or contact injury.

Abrasive Wheels Practice Test

Abrasive Wheels Practice Test

Abrasive Wheels Training Certificate Guarding Requirements