Lifting plans, multi-crane lifts, personnel lifting and exclusion zones
A lifting plan documents the lift: load mass and centre of gravity, rigging, crane position and configuration, radius, chart capacity, ground conditions, environmental limits, personnel roles, communication and contingencies. Routine lifts may use a generic plan; complex, high-risk or unfamiliar lifts need a specific, engineered plan. Complex lifts include tandem or multi-crane lifts, lifts over live plant or public areas, and lifts near powerlines.
Multi-crane lifts demand a single controlling mind, matched load sharing, planned synchronisation and a defined sequence. Load share is rarely equal and changes as geometry changes. Personnel lifting by crane is high risk and only permitted where there is no safer alternative, using a certified man box, a dedicated plan, secondary retention, reduced capacity, no free fall and a controlled lowering capability.
Exclusion zones keep people out from under and near the load and the slew path. Define the zone by the task, barrier it physically, and control entry. Never allow personnel under a suspended load.
Traps: treating a multi-crane lift as two independent lifts, allowing riders in a general-purpose box, and marking an exclusion zone without enforcing it.
Rule of thumb: if the plan does not state radius, configuration, gross load and ground control, it is not a plan. Worked example: a two-crane lift of a 20 t vessel at 60 degrees included angle gives 11.55 t per crane; capacity must be checked at the actual radius for each crane with the full share plus rigging.