Hitch Selection for a Long Pipe
You need to lift a 20-foot long, 8-inch diameter steel pipe weighing 800 lb. The pipe is horizontal and must remain horizontal during the lift. You have two chain slings with hooks. The available lifting points are at each end of the pipe, but there are no lifting eyes. You must use a hitch that will not allow the pipe to slip out. The pipe surface is smooth.
1. Which hitch configuration is most appropriate and why?
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A double-wrap choker hitch or a basket hitch with both ends hooked to the crane hook would be appropriate. A single choker hitch can allow the pipe to slide if the load shifts. A basket hitch provides a more secure grip and distributes the load over a larger area. However, since the pipe is smooth and long, a basket hitch with the sling under the pipe and both eyes on the hook would keep the pipe horizontal and prevent slipping. Alternatively, two choker hitches, one at each end, with the chokers positioned to prevent the pipe from sliding out, but choker hitches can reduce capacity. The best is a basket hitch because it does not reduce capacity as much and grips the load securely. Ensure the sling angle is considered: if the slings are vertical, capacity is maximized.
2. What capacity reduction applies to a choker hitch compared to a vertical hitch?
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A choker hitch reduces the capacity of a sling to 75-80% of the vertical hitch capacity, depending on the sling type and angle. For chain slings, the choker capacity is typically 80% of the vertical capacity. For wire rope, it's 75%. Since the pipe is smooth, a choker might still slip, so a basket hitch is preferred. Also, the angle of the choker affects capacity: if the choker angle is less than 120 degrees, capacity is further reduced. Always consult the sling manufacturer's data.