OHS Code Explanation Guide

Published Date: July 01, 2009
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Part 6 Cranes, Hoists and Lifting Devices

Section 108 Safety requirements

Figure 6.43 shows an example of an underground shaft hoist.

Figure 6.43 Example of an underground shaft hoist and its parts

Section 108(1)(a)

The base of an underground shaft hoist will typically be a rigid concrete foundation that should be designed by a professional engineer.

Section 108(1)(b)

“Positive drives” means that the load-carrying unit is driven in both up and down directions. “Non-positive” (free-wheeling) means that that load-carrying unit is driven in the up direction and may be permitted to descend freely.

Section 108(1)(c)

Installation of a clutch is prohibited to prevent disengagement of the positive drive mechanism either through mechanical failure or accidental activation of the clutch control.

Section 108(1)(d)

The braking system should be able to:

(a) stop the cage within the deceleration parameters specified by the manufacturer or a professional engineer, for both the descending and ascending modes;

(b) apply automatically in the event of a power failure, whenever the safety circuit of the hoist is interrupted and whenever the pressure in the hydraulic or pneumatic brake actuating system drops below normal; and

(c) be applied by the hoist operator in the event of an emergency.

No hoist should be used for the transport of workers unless it has at least two sets of mechanical brakes each of which should:

(a) be capable of safely stopping and holding the drum when carrying its maximum rated load;
(b) be arranged so that it can be independently tested;
(c) be arranged to apply normal braking effort before any linkage or brake piston reaches a limit of travel; and
(d) if of a drum type, be equipped with a device to give positive indication of tread wear or slack linkage and prevent any movement of the hoist if predetermined limits are exceeded.

Section 108(1)(e)

A positive spring-actuated pawl remains engaged until manually released and then returns to the engaged position when the manual control is released. See Figure 6.44.

Figure 6.44 Example of a spring-actuated pawl mechanism

Subsections 108(2) to 108(4)

The required communication system should

(a) enable clear, audible signals to be given that are separate and distinct for each shaft compartment,
(b) be arranged so that the hoist operator can return a signal to the person giving the signal, and
(c) be installed throughout the shaft and at every working level, landing deck and other necessary location.

A hoist should not be moved on manual control unless the prescribed signal has been given and returned by the hoist operator. Signaling systems should be tested daily. Optional systems include voice, telephone and speaking tube.