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Mobile Crane Safety: Operational Checklist for Proper Critical Lift Planning

Mobile cranes are extremely useful for a variety of construction applications, particularly when compared with tower/other stationary cranes. They use up little space, are easier to manoeuvre in limited space, have multiple turning axles giving them more hoisting power and they require minimal assembly time.

However, just like all cranes, there are inherent dangers associated with mobile crane operation, hence the need for careful planning prior to operation to prevent incidents that may result in property damage and injuries and fatalities within the construction site. The following are important points to be considered during critical lift planning:

Critical lift definitions

All crane lifts demand intimate knowledge of the load weight, including all other components that contribute to this weight among other factors. However, critical lifts require more detailed planning and surveillance by qualified persons. Critical lifts are defined as lifts which:

  • require two or more cranes working together
  • hoist loads exceeding 75% of any crane’s rated capacity
  • include lifting of personnel
  • involve lifting directly above on-site personnel
  • on moving exit the direct view of the operator at any point
  • include irreplaceable, irreparable or otherwise valuable loads
  • include loads that could potential damage other utilities or equipment
  • are potentially unstable during lifts
  • occur in congested areas among many obstacles, e.g. power lines, pipelines and permanent structures
  • involve flips, turns, shock loading or side loading manoeuvres
  • occur in poor/unknown soil/ground conditions

Critical lift plan drafting points

It is advisable to draw up a formalized lift plan for all critical lifts, which must be approved by a qualified manager before every lift operation. The plan may span just two or several pages depending on what information is considered necessary. It must evaluate the mobile crane’s configuration, precise rigging and loading details and rated capacity.

In addition, it should evaluate any other components which may contribute to structural or stability failures while the crane is in operation e.g. the hoist line or rigging. The following are the most important details to be included in the lift plan:

  • Lift description, including drawings
  • Mobile crane configuration – details such as:
    • counterweights used,
    • erected or stowed jib,
    • lifts from main hoist or jib,
    • offset angle and length of jib,
    • load line part numbers,
    • load line size, boom length,
    • maximum load radius,
    • boom-point elevation,
    • load/boom clearance distance,
    • boom length, origin angle and destination angle etc.
  • Crane rated capacity: over-the-side, over-the-front and 360 degree rotation
  • Load weights including:
    • empty load mass
    • main block
    • spreader/lifting bar
    • headache ball
    • shackles and slings
    • jib effective weight
    • auxiliary line weight
    • hoist line weight
    • any other items specified as part of load weight by crane manufacturer
  • Rigging capacity, with slings and load attachments
  • Load percentage of crane’s rated capacity
  • Any factors affecting crane’s rated capacity

From this information, a qualified manager should assess whether or not it is safe to use the crane for the intended job.