A tandem lift is a tricky, dangerous operation. The critical crane lifts require planning, experienced supervision, and precise execution. Without proper planning and execution, an operation can quickly turn into an OSHA statistic.
Keep reading to learn about the engineering specifics involved in a critical lift.
Planning a Critical Lift
Cranes and hoists working in tandem are like poetry in motion. When a plan goes right, the cranes move smoothly, with operators and supervisors working in a beautiful rhythm.
Before the lift, though, much planning takes place.
Anytime a hoisted load nears a crane’s maximum capacity, the load qualifies as a critical load. Maximum capacity refers to 70% to 90% of a crane’s capacity.
More than weight capacity qualifies a lift as a critical lift. A lift is critical if the lift:
- Hoists personnel.
- Hoists hazardous materials.
- Requires two or more cranes.
- Occurs on a floating barge.
- Occurs near power lines.
- Occur in a blind spot, out of the view of the operator.
- Involves technically difficult rigging arrangements.
- Occurs in congested areas.
- Involves flipping or turning a load.
- Involves an unknown load weight.
- Occurs in unknown ground conditions or poor soil.
- Involves unstable pieces.
Any time that environmental conditions make the lift dangerous or any time a crane operator believes the lift is critical, the lift can qualify as critical.
All crane lifts require pre-lift planning. Because the potential of crane failure or catastrophic loss is much higher with a critical lift, critical lifts require a thorough lift plan.
Parts of a Critical Lift Plan
An experienced supervisor will be able to complete a critical lift plan with ease. It must have the following information in it:
- The position and configuration of the crane or cranes involved.
- A description of the lift.
- Height of the lift.
- Load radius.
- Boom angle and length.
- Percent of the crane’s rated weight capacity.
- Size and weight of the load.
- Rigging plan.
- Personnel involved.
- Communication method.
- Environmental conditions, including the ground conditions.
- Inspection procedures.
Each of these elements ensures a safe lift in critical conditions. Without proper planning, the critical lift can turn deadly.
The Feat of Tandem Cranes
Cranes working in tandem are responsible for the architectural and engineering feats we take for granted every day. The beautiful hospital on the horizon of our city or the multi-tiered freeway we take to work is all a result of skilled engineers and crane operators working in tandem to put the pieces together.
Because a tandem lift is a critical lift, it requires the same kind of lift plan. However, because two cranes are working together, the tandem lift plan has more requirements.
Critical crane lifts involve tandem crane operations must have a written lift plan with the following details to ensure a safe lift:
- Crane positioning
- Lift sequence
- Load movement including the exact measurements of the longest radius of each crane)
- Load distribution and transfer
- Boom clearance
- Clearance and weight of obstructions
- Environmental considerations
- The rated capacity for each crane involved
- Angle indicators for each crane
- Wind speed limitations
- Rigging details
- Maximum hoist line
- Maximum crane travel speed
- The need for and the position of signalers
Because of the complexity of having multiple cranes working on a single operation, you need an experienced supervisor. The supervisor may not operate the powered lifting equipment.
Big Beautiful Builds
The key to a successful critical lift is communication, reliable equipment, and knowledgeable supervisors. The results are some of the most amazing human-made structures on earth.
For the best cranes out there, contact us. Our reliable equipment can help you with your next critical lift.