Acceptable damage in climbing line?

[Viking]

Ropes do get nicked, picked, and strands snagged etc. Its the real world, and it happens sometime. Is there any info/standards/rules or regs than allow a safety buffer with non-pristine ropes? I seem to remember Todd Kramer telling the group at an OTCC sbout about an unacceptable number of cut strands per X ammount of rope feet, but maybe it was a dream! Any help or insight? I know when in doubt throw it out

 

[tophopper]

Depends on rope construction......


me? one cut strand is enough.

 

[Kip_Durron]

25% of fibers picked, napped cut or whatever, is the manufacturers standard ruling. So with a 16 strand rope, when 4 strands are gone, or equivalent, it's time to retire the rope.

If the same rope has 2 picks at one end and two at the other end of a 300 foot line, that's probably OK, but the 25% rule is what would apply. Same for 24 strand double braid, except that you can't inspect the core, so you have to make a judgement.

Its a good reason to document the use your climbing lines go through. Perhaps not every day, but whenever something wierd happens.

http://www.samsonrope.com/site_files/Double_Braid_Inspection_and_Retirement.pdf

http://www.samsonrope.com/site_files/Single_Braid_Inspection_and_Retirement.pdf

 

[treebing]

Lets say that the sheath takes 100% of the load to be on the safe side. a poison ivy double braid 24 strand breaks at 6500 lbs. If you cut one strand, than take off 270 lbs (6400/24 from the breaking strength. 6500-5400 = 1100. 1100/270= 4. Therefore, you should be able to cut four strands out of your 24 strand from the same spot and it would still hold 5400 lbs. That is assuming that the core does nothing. in reality you could cut quite a few more and still break above the 5400 lbs mark. I'm pretty sure if I had 4 cut strands right next to each other, I would retire the rope, but mathematically you should still be ok.

 

[Raven]

If you gotta ask, then make it the next dog run and enjoy yerself a shiny new climb line.

Or show your wife the damage and see what she says.

 

[Fernhorn]

Interesting question- Also, Could the sum of the parts compromised vs intact lead to perhaps more markdown of rope strength? or perhaps an example to envision what I'm asking - an arch relies on every part supporting another for its strength.

Having seen how much an old hank of blue streak can handle with tons abuse I figured my climbing line looked pristine in comparison so I haven't been worried by the minor dings too much.

 

[Norm_Hall]

[ QUOTE ]
Ropes do get nicked, picked, and strands snagged etc. Its the real world, and it happens sometime. Is there any info/standards/rules or regs than allow a safety buffer with non-pristine ropes? I seem to remember Todd Kramer telling the group at an OTCC sbout about an unacceptable number of cut strands per X ammount of rope feet, but maybe it was a dream! Any help or insight? I know when in doubt throw it out

[/ QUOTE ]

25% wear is correct. You must incorporate the wear along with the number of cut fibers or strands. Maybe 25% of the strands cut could mean more than 25% strength loss, depending on the amount of wear.
Each strand that is cut, puts that much more force on the remaining strands.