Dead Wraps: The first few wraps of the wire rope around the drum (commonly known as
the "dead wraps") provide a simple and secure method of anchoring the wire rope
to the drum. This (anchoring) is accomplished by the friction (of the dead wraps)
tightening against the drum barrel, as a load is applied. As the load on the wire rope
increases so does the anchoring effect. It is critical that the recommended number of dead
wraps remain on the drum at all times in order for the load to be held. The number of dead
wraps varies according to what prevailing agency or regulatory body’s rules are
followed. In the United States, Ingersoll Rand exceeds ANSI / ASME B30.7 (BASE
MOUNTED DRUM HOISTS) by recommending that a minimum of (3) dead wraps are kept on the drum
at all times.
(Note: Because of the dead wraps the amount
of usable wire rope on the 1st layer is diminished slightly. This has been
factored into each of the drum calculator outputs.