What is Tandem Lift working Procedure and Preventive action
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| Tandem lifting Definitions |
Tandem Lift: Definition:
A tandem lift involving the simultaneous use of more than two cranes, hoists or other pieces of powered lifting equipment.if the load on any one crane, hoist or other piece of powered lifting equipment exceeds 75% of the rated capacity of that crane, hoist or other piece of powered lifting equipment.
A two crane or tandem crane lift is where two cranes are used to support a load where their
hooks are attached directly to an equalizer beam or to the load by slings or lugs. Up-ending a
vertical vessel using two cranes on the top end and a tailing crane of the bottom end would still be considered a two-crane lift.
There are two ways to make a two crane lift, equalized and unequalized Equalized
One way a lift can be equalized is where the load is supported by a link and pin at the center of an equalizer beam and both crane hooks are connected to either end of the equalizer beam with links and pins.
Unequalized
An un-equalized lift is where two cranes are hooked directly to the load and any out of levelness of the hooks causes a large increase in load to one crane.
Recommended Preventive Action for Tandem Lifting:
1. Lifts involving two or more cranes are complex operations requiring
considerable skill and planning. As a result, multiple crane lifts
(or tandem lifts) must be planned and carried out under a competent
person’s supervision.
2. The competent person must develop and communicate a detailed lift
plan that contains, but is not limited to, the following:
• Crane positioning
• Rigging
• Lift sequence
• Load movement (the longest radius of each crane for the
complete operation must be measured exactly)
• Weight and clearance of obstructions
• Load transfer and distribution
• Boom clearance
• Environmental considerations
• Rated capacity of each crane for the whole operation
3. Boom angle indicators are required on all mobile cranes, but they must
not be relied upon for accuracy in critical lifts such as tandem lifts.
A load moment indicator (LMI) gives an accurate angle as well as loading
throughout the lift
(1) If a tandem lift is a critical lift or if the lifted load is to be moved laterally, the tandem lift must be carried out under the direction of a qualified supervisor who
(a) is not operating a crane, hoist or other piece of powered lifting equipment, and
(b) is responsible for the safe conduct of the operation.
(2) A written lift plan must be prepared for every tandem lift and must be available at the worksite during the lift.
(3) The lift plan required in subsection (2) must include the following:
(a) rigging details;
(b) wind speed limitations;
(c) maximum hoist line speed;
(d) maximum crane travel speed, if applicable;
(e) load distribution;
(f) the need for and position of signallers.
(4) If a tandem lift involves the use of a tower crane, the lift plan required in subsection (2) must be certified by a professional engineer.
(5) At a pre-job meeting held immediately before commencing hoisting operations for a tandem lift, the lift plan required in subsection (2) must be communicated to all people involved and the supervisor must document the meeting.
(6) The pre-job meeting required under subsection (5) must be repeated whenever there is a change in the people or equipment involved in the tandem lift.
(7) Effective communication must be established and maintained between all people involved in a tandem lift.
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