OHS Code Explanation Guide

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

Section 97 Safe use and design

Subsection 97(1)

The counterweights used with a roofer’s hoist (see Figure 6.32 and 6.33) must

(a) be clearly designed to work as part of the hoist,
(b) stay in place and remain firmly attached until the lifting operation is complete, and
(c) provide a factor of safety against overturning of not less than 4.

Figure 6.32 Properly designed counterweights for a roofer’s hoist

Figure 6.33 Examples of roofer’s hoists

The weight of the counterweight can be calculated using the following formula:

The length of the outboard arm is the horizontal distance measured between the hoist’s fulcrum point and the hoisting line. The length of the inboard arm is the horizontal distance measured between the hoist’s fulcrum point and the counterweight’s centre of gravity (see Figure 6.34).

Figure 6.34 Illustration of “inboard” and “outboard” arms

Subsection 97(2)

Roofing materials cannot be used as counterweights. Counterweights must work as part of the hoist and remain secured in place while lifting. Bundles of roofing material can be unstable and are intended to be removed as work progresses, gradually reducing the weight and effectiveness of the counterweight.

Subsection 97(3)

Before use each day, the hoist must be inspected by a competent person designated by the employer. The inspection must be in accordance with the manufacturer’s specifications and should include, but not be limited to, the following:

(a) members and welds in the hoist structure;
(b) bolts, nuts, pins;
(c) sheaves, ropes;
(d) brake and clutch systems, pawls, ratchets;
(e) control devices.

Subsection 97(4)

Figure 6.35 shows an example of a safety pin that is used on the bolts and pins of a roofer’s hoist. The bolts and pins hold the hoist’s components together – the safety pin prevents the bolts and pins form dislodging.

Figure 6.35 Example of a standard safety pin

Subsection 97(5)

Roofer’s hoists are not typically designed to create or withstand horizontal forces that occur when swinging a load or pulling a load across a surface. Such horizontal movements could lead to overturning or component failure.

Subsection 97(6) and 97(7)

Gallows frame hoists are rarely used today, but may be found on relatively minor repair jobs. Where such a hoist is used, its construction must comply with the design limits specified in this subsection.