Black Diamond carried out some tests to find out if letting your rope rest between falls would help to reduce the peak forces experienced in a fall. They did tests where the rope was left to rest for 30 mins, 2 hours and 24 hours. They also checked to see if loosening the knot after a fall helped to reduce peak forces.
The graph shows successive falls from 1-10, with peak force on the vertical axis (using antique lbf as units, 1000 lbf = roughly 4.4 kN).
Their conclusions were:
"As expected, progressive drops resulted in increasing forces
The largest increase was from the 1st to the 2nd drop as expected
Loosening the knot after each fall reduced the load a bit, but not much
Letting the rope rest 30 min between drops had a bigger effect at lowering loads than loosening the knot, but still not much
Allowing the rope to rest for 2 hours and 24 hours had an even greater effect at reducing the loads on the 2nd drop, as expected
Allowing the rope to rest 24 hours still resulted in a 2nd drop load of 11% greater than the first drop"
The graph shows successive falls from 1-10, with peak force on the vertical axis (using antique lbf as units, 1000 lbf = roughly 4.4 kN).
Their conclusions were:
"As expected, progressive drops resulted in increasing forces
The largest increase was from the 1st to the 2nd drop as expected
Loosening the knot after each fall reduced the load a bit, but not much
Letting the rope rest 30 min between drops had a bigger effect at lowering loads than loosening the knot, but still not much
Allowing the rope to rest for 2 hours and 24 hours had an even greater effect at reducing the loads on the 2nd drop, as expected
Allowing the rope to rest 24 hours still resulted in a 2nd drop load of 11% greater than the first drop"
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