TM 5-3810-307-10
Use cranes and rigging of equal capacities and use the same boom lengths.
Be certain of adequate lifting capacity. Calculate the amount of weight to be lifted by
each crane and attach slings at the correct points for proper weight distribution.
DO NOT TRAVEL - Lift only from a stationary position.
If it is necessary to perform a multi-crane lift, the operator shall be responsible for
assuring that the following minimum safety precautions are taken:
1.
Secure the services of a qualified engineer to direct the operation.
2.
Use one signal person and be sure he is qualified.
3.
Coordinate lifting plans with the operator, engineer, and signal person prior
to beginning the lift.
4.
Use cranes and rigging of equal capabilities and use the same boom length.
Be certain cranes are of adequate lifting capacity.
5.
Use outriggers on cranes so equipped.
6.
Calculate the amount of weight to be lifted by each crane and attach slings
at the correct points for proper weight distribution.
7.
Lift only from a stationary position - DO NOT TRAVEL.
8.
If possible, provide approved radio equipment for voice communication
between all parties engaged in the lift.
9.
Ensure the load lines are directly over the attach points to avoid side loading
the cranes.
2-5.
TWO BLOCKING.
To avoid death or serious injury, keep load handling devices away from boom/jib tip when
extending or lowering the boom and when hoisting up.
This crane should have a functional ANTI-TWO BLOCK and CONTROL LOCK-OUT
system. Test daily for proper operation.
Do not pass loads or boom over ground personnel.
Two blocking occurs whenever the load block (hook block, headache ball, rigging, etc.)
comes into physical contact with the boom (boom nose, sheaves, jib, etc.). Two blocking can
cause hoist lines (wire rope) rigging, reeving, and other components to become highly stressed and
overloaded, in which case the wire rope may fail allowing the load, block, etc., to free fall.
