OHS Code Explanation Guide

Published Date: July 01, 2009
Bookmark this page

Part 6 Cranes, Hoists and Lifting Devices

Section 68.1 Lift calculation

Performing a lift calculation ensures that relevant and applicable factors for lifting a load have been considered and calculated. These factors include:

(a) load information (total weight of item to be lifted, weight of load block, weight of rigging/attachments, load centre of gravity, if applicable;

(b) crane information:

(i) mobile cranes i.e. maximum radius, boom length/angle, configuration, relevant deductions, etc.;
(ii) overhead cranes; i.e. capacity;

(c) calculated percentage of crane capacity; and

(d) sketch i.e. crane placement, clearance to surrounding facilities like buildings and power lines.

While this is a good practice regardless of the load weight, it is critical as the load approaches the crane’s capacity. This calculation must be performed when the load reaches or exceeds 75 percent of the crane’s capacity.

For multiple lifts, the “worst-case” lift can be used to satisfy this requirement. In the case of tower cranes, lifting operations are typically planned or engineered and test weights are lifted daily. This would satisfy this requirement.

Figure 6.9.1 Example of hoisting information and planning sheet

Figure 6.9.2  Example of lift calculation form (A)

Figure 6.9.3   Example of lift calculation form (B)