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Pop Quiz

True or false: The most common slings used in arena rigging are made from chain link.

TRUE OR FALSE

1. The most common slings used in arena rigging are made from chain link.

2. “Shock loading” and “sudden loading” mean the same thing.

3. For overhead lifting, a safety factor of 5 to 1 should be considered the minimum.

4. Hang point redundancy, or “safeties,” only work when there is no slack on the safety cable.


ANSWERS

1. FALSE. Wire rope slings are used at least 95 percent of time in arena rigging. Wire rope, sometimes known as aircraft cable, weighs and costs less than chain link of equivalent capacity and is easier to handle.

2. FALSE. Shock loading refers to the force applied to rigging, including cabling and all hardware, when a weight free-falls. The fall continues until the rigging is jerked taut and then stretches as it brings the weight to a stop. Sudden loading occurs when a load is suddenly applied to a cable, such as when a hoist jerks a load off the ground. In contrast to a shock load, the weight does not fall. Both situations can damage cabling to the point where it must be replaced.

3. TRUE. Safety factor, or design factor, equals the rigging strength divided by the load. If the calculation results in a number less than five, you must either reduce the load or increase the rigging strength.

4. TRUE. If a hang point fails, and there is a secondary safety cable but there is slack on that cable, it will suffer from shock loading and may not be able to stop the load from falling to the floor.

Source: “Entertainment Rigging” by Harry Donovan (www.riggingbooksandprograms.com)



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