When is a rope to old?

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When is a rope to old?

Postby pink flamingo thief » Mar 9, 2013 9:11 pm

I have a 400 ft rope that has only been used by 6 people. The problem is that it's 25 years old It has only seen the day light maybe a 4 times the longest time 8 hours. Has been stored dry and in a canvas bag. It has been nowhere near any any chemicals. Is it safe for use?
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Re: When is a rope to old?

Postby Stridergdm » Mar 10, 2013 12:26 am

pink flamingo thief wrote:I have a 400 ft rope that has only been used by 6 people. The problem is that it's 25 years old It has only seen the day light maybe a 4 times the longest time 8 hours. Has been stored dry and in a canvas bag. It has been nowhere near any any chemicals. Is it safe for use?


"Probably". I don't think anyone can give you a definitive answer and the rope manufacturer almost certainly won't.

That said, honestly, I'd visually (for wear, funny spots, etc) and manually inspect it (run the whole thing through my hands, feeling for anything "that's not right").

Assuming I didn't see any issues, I might consider using it.

Nylon is fairly stable stuff and well stored nylon isn't likely to lose much strength.
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Re: When is a rope to old?

Postby killian » Mar 10, 2013 9:07 am

manufacturer for static rope is normally 10 yrs i think. 5 for dynamic. that being said i had a static rope that i used for ten yrs then left it out side in a tree as a haul rope for 2 yrs. it looked good but for fun i tied it to a tree and to a chey tahoe. had to put it in toe and bounce on it to break it... broke at the not too were it should. that stuff is pretty stuff. but guess it comes down to if u are willing to put ur life on it or that of ur caving partners??
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Re: When is a rope to old?

Postby Leclused » Mar 10, 2013 1:54 pm

In our club we use these guidelines
- 7 years for short ropes (<40m)
- 7 years for long ropes (>40m) OR an extra year after a breaking test with a max of 10 years.

Why we don't test the shorter ones:
- it's too much work and you end up with a lot of really short ropes :-). For each test you need some metres of rope.
- the shorter ones are used more often then our long ones

An other guideline

- If a rope is damaged during a trip, the rope is cut in two and the damaged part is removed.

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Last edited by Leclused on Mar 11, 2013 7:04 am, edited 1 time in total.
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Re: When is a rope to old?

Postby chh » Mar 10, 2013 4:48 pm

I think the more appropriate thing to evaluate here is the 6 people who used it previously. 1 person can thrash a rope :laughing:
Provided it was used infrequently, stored well, and cared for, and undergoes an inspection. I'd probably use it depending on it's diameter. A 25 year old 11 or 12 mil rope that's been treated kindly is still probably safe for normal use. My 120' 11mm was a hand me down rope. I've got no idea how old it is, but it's at the very least 12 years old, and realistically probably more like 20. I use it without worry. It's still in good shape and been stored well. I have a feeling that if I cut off a section and took it to be tested it would still test to appropriate limits. Have I done so? No. That being said, it was only ever used by one person previously and I know exactly where and how it was stored.
I've clipped into all kinds of fixed lines and rap anchors over the years. And climbing fixed lines (if I don't know who put them there) always gives me pause. So what to do? Subject it to the Fat Boy Test, cross your fingers, and cave on. I use the FBT at work a lot, substituting a z drag, or more bodies when I don't actually have a Fat Boy handy. Will it be strong enough? Probably. You just have to decide if "probably" is an acceptable answer to you.
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Re: When is a rope to old?

Postby pink flamingo thief » Mar 10, 2013 9:47 pm

Thanks for all the info. I will cut and stress test a short piece. Then make my mind up.
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Re: When is a rope to old?

Postby Extremeophile » Mar 11, 2013 10:56 am

pink flamingo thief wrote:Thanks for all the info. I will cut and stress test a short piece. Then make my mind up.

So who has the equipment to conduct pull tests on rope? Care to share your techniques? A grotto friend recently purchased a S-type, 10,000 lb load cell to conduct this type of testing, but they haven't set up the actual pulling equipment. If you tie off a rope with a knot then it's likely to break at the knot and give you a lower number, so some sort of tensionless jig would be needed. I've heard of people using something like a 5-ton come-a-long to generate the pull force, but then you're in the line of fire as you conduct the test. Winches would increase the cost and complexity of doing this type of testing.

I cut off 1 foot of my oldest PMI rope, which I recalled purchasing in 1994. The tracer tape said 2nd quarter, 1992. At least I know precisely now. The sheath was gray with aluminum residue from an old SMC rack, but had very few broken fibers and was incredibly tough to cut. The core strands looked brand new. I'd love to know the tensile strength quantitatively.
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Re: When is a rope to old?

Postby chh » Mar 11, 2013 11:11 am

Hey Derek,
A quick Google search turned up Cable Tech Sling & Supply Co. in Denver. It says they manufacture their own slings and cable rigging. They will have a test rig. They may charge you a little money for the time it takes them to set up the rig and perform the test, but I'm sure they would pull a section to failure for you if you really wanted to know.
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Re: When is a rope to old?

Postby Extremeophile » Mar 11, 2013 12:11 pm

chh wrote:Hey Derek,
A quick Google search turned up Cable Tech Sling & Supply Co. in Denver. It says they manufacture their own slings and cable rigging. They will have a test rig. They may charge you a little money for the time it takes them to set up the rig and perform the test, but I'm sure they would pull a section to failure for you if you really wanted to know.
-caleb

Then there are these guys:
http://www.rockymountainrescue.org/randd.php
One of the members is an avid caver and has offered to spend some time to test materials. I was just curious if grottos or individuals have their own test equipment.
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Re: When is a rope to old?

Postby wyandottecaver » Mar 11, 2013 5:54 pm

I removed a fixed rope (11mm) that had been rigged in-cave for over 30 years. It was pull tested at a caver friends workplace lab at something like 70% of original.. The cave humidity probably helped in this case.

I would gladly let someone else of limited means use that rope for caving use (telling them the history). If *I* am hanging on it, I'll use fresh rope thank you very much :tonguecheek:
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Re: When is a rope to old?

Postby ohiocaver » Mar 14, 2013 9:10 am

The moment you question the age or integrity of your rope, it is too old. In your heart, you know it's spent. Figure whether you want to spend your money on 250 feet of rope versus a coffin. Rope will win every time.
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Re: When is a rope to old?

Postby chh » Mar 14, 2013 5:24 pm

Everyone knows you don't buy your own coffin :laughing:
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Re: When is a rope to old?

Postby NZcaver » Mar 20, 2013 1:47 am

I have a piece of rope that's about 25 years old, well used for caving and then used for a decade outdoors as a short zip line. It's waiting to be pull tested... when I stop using it (just kidding about that last part). :big grin:

Seriously though, a friend with access to testing facilities is working on coming up with 'realistic' parameters for testing caving ropes (i.e. not slow-pull). He may appreciate receiving more samples to test, particularly if they have documented history of use.
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Re: When is a rope to old?

Postby Extremeophile » Mar 20, 2013 12:17 pm

NZcaver wrote:a friend with access to testing facilities is working on coming up with 'realistic' parameters for testing caving ropes (i.e. not slow-pull). He may appreciate receiving more samples to test, particularly if they have documented history of use.

Why is slow pull not realistic? I'm assuming you mean a test to failure. It seems like the only standard tests out there for rope are pull tests and drop tests. A pull test will give you a quantitative measure of the tensile strength of the rope, which seems to be the most useful for calculating safety factors for uses such as SRT or rescue hauling. I'm not sure exactly how to use drop test results for static rope. It seems that FF1 is typically used, but I wouldn't ever want to be subjected to a FF1 impact on a static rope. It also sounds like knot tightening and body squishing (I think that's the technical term) significantly reduce these FF loads. So if a rope survives 4 FF1 drop tests is that good? I really don't know how it helps me decide whether to retire a rope or not.

I've seen some abrasion resistance test procedures, but these don't seem to be standardized and could easily be manipulated to make one material look better than another.
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Re: When is a rope to old?

Postby Extremeophile » Mar 20, 2013 12:31 pm

wyandottecaver wrote:I removed a fixed rope (11mm) that had been rigged in-cave for over 30 years. It was pull tested at a caver friends workplace lab at something like 70% of original.. The cave humidity probably helped in this case.

I'm not sure why the humidity would help. Nylon weakens slightly with exposure to water, but this is reversible and doesn't suggest a long-term degradation from being wet. My guess is that the 30% loss in strength is due to wear from use rather than any chemical change in the polymer or exposure to adverse environmental conditions.
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