Surviving Sedona.....January 8th is my new second birthday

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Clint Cummins

Trad climber
SF Bay area, CA
Jan 14, 2013 - 05:38am PT
I agree that testing might potentially weaken a sling or anchor component so that it would then fail under a lower load than if untested.
Such a "test-weakened rappel sling failure" seems unlikely to me, though.
Probably this is based on some years back, where I towed my car with a motley collection of slings, including some 1/2" webbing that I thought was junk.
Nothing broke, in spite of many repeated jerks when accelerating after each stoplight. And much larger loads than we can generate rappelling, even with big guys and lots of gear.

But we want a rule which keeps the risk below an "acceptable" level.
What's acceptable to me might not be acceptable to other folks (even if we had a good estimate of the failure probability), so I don't expect my methods will be best for everyone.

Example rappel anchors with new slings and rings, clean rope:
1. One sling, no rings.
2. One sling, one ring.
3. One sling, two rings.
4. Two slings, no rings.
5. Two slings, one ring.
6. Two slings, two rings.
7. Three slings, three rings.

Every time we add redundancy, we reduce the failure probability.
I'm fine with #1, especially if I think it will never be used again.
I've had partners who insist that #1's risk is too high - they want one of the safer options.
#6 is fairly standard, for a frequently used rappel station.
#7 is safer, though....

Yes, the gear is cheap.
It takes a little effort and time to bring the gear along and add redundancy.
Whether it is worth the extra effort/time depends on your level of acceptable risk and how you value your time.

And the above 7 anchors are a situation where we can have good estimates of the breaking strengths of the components.
The probabiliy of failure is very low in #1 and gets ridiculously low in the others.
So if we can't solve the above, there's no chance in making an easy-to-use rule for making acceptable anchors with partly faded slings.

JLP has a reasonable point that if:
1. a sling "looks/feels bad enough", and
2. we have enough spare webbing,
then we should just replace it instead of testing it.

The main problem is that you have to develop a set of rules for (1.) "looks/feels bad enough" to calibrate them against sling failure probability.
You need testing (by yourself or others) to develop this set of rules.
I do it often when I'm removing tat, because I want to see if I can predict how weak a sling is from its look and feel.
And you might want to do continued random testing of slings that meet your rules for safety, to make sure your rules still work in a new area.

And what if you don't have (2.) sufficient spare tied slings to reach around a big block (Jim's exact situation, 8')? If you have a knife (I carry a tiny one), you can cut off the end of one of your ropes and use that. But there had better be a good reason to do that (it will create other risks and it's not cheap). Spot testing in such a situation is no guarantee you will live if the sling holds, but if the sling fails under test you have learned something important.

Finally(?), testing also tests more than just the slings.
One of the goals is to uncover unobserved flaws in the anchor system.
So I believe testing is still quite useful in the real world.
drljefe

climber
El Presidio San Augustin del Tucson
Jan 14, 2013 - 06:50am PT
If it's white, it ain't right!

Credit: drljefe
bomber
High Fructose Corn Spirit

Gym climber
-A race of corn eaters
Jan 14, 2013 - 07:23am PT
EH wrote,
I'm with JLP on this...

Riley wrote,
I'm with JLP also.
We really shouldnt even have to debate this one.

To be clear, let's take the two specific points I referenced, no better, criticized. You guys are with JPL regarding...
the sling can hold 500 lbs for 5 seconds and your testing uses up about 3 seconds of that
Really? Testing uses up time? Citations from either modern engineering physics or life experience, please.
Sample of one and no controls doesn't tell you anything...
Really? So if I encountered a slung boulder in the manner described by JD: an old badly weathered 1" sling that I was thinking about rapping from, testing it wouldn't tell me anything? Let's say, I recognize it as weathered, it's testable under daisy chain and in the line of force (a point JD was not clear about), I bounce test it to 8-10 g, it holds, moreover this simple part system still looks same; also taking into account my intention to rappel the line smoothly at 2g max say, precisely because it is a compromised questionable system... then this, according to JPL, "doesn't tell you anything"?

But you're right, Riley, we shouldn't even have to debate this one.

.....

No one's arguing, I don't think, that an extra sling wouldn't have strengthened the system. Geez.

But to not test the system (under load, many times body weight, too, by bouncing, under visual inspection, while backed up) esp when possible, esp one suspected of being dangerous, is neglectful if not foolish. That's the main point. Applies to rapping off old bolts as well as slings, too. Obviously.

Testing the system before use saves lives.

.....

Donini curiously has remained mum (even since my first post) regarding (a) whether this rap station lended itself well to apriori load testing (some don't); (b) whether or not he in fact tested the system (I suspect not).
donini

Trad climber
Ouray, Colorado
Topic Author's Reply - Jan 14, 2013 - 07:32am PT
I didn't test it. I was completely off base rapping on the, obviously, badly UV damaged sling. My point in posting was that even someone who has rappelled as many times as me can make a bonehead decision.
Do Not become blase about rappelling!!!
It is the single most dangerous thing that climbers do!!!
The best climber in the world is not going to change the results of a failed anchor!!!

Diligence....Diligence....Diligence!
PhilG

Trad climber
The Circuit, Tonasket WA
Jan 14, 2013 - 07:35am PT
Jim,
I just hope them younger climbers are listening up and paying attention.
mcreel

climber
Barcelona
Jan 14, 2013 - 07:43am PT
Yow! Nothing like a little good luck when you need it!
rgold

Trad climber
Poughkeepsie, NY
Jan 14, 2013 - 08:59am PT
JLP--I posted a link and a quote from the BD QC Archive that might well have been what Jim remembered. Note the part I rendered in bold. I have both read and been told about other tests that reached similar conclusions. A lot of old tat is, in fact, good enough for rappelling.

I've never bounce-tested a rap anchor and don't imagine I ever would, unless perhaps I was faced with either using what is there or cutting the rope. Adding good webbing makes far more sense than trying to test the old stuff in my opinion, and as I said previously, I've also taken to backing up all rappels for the first person down whenever it is easy and efficient to do so, which has been most of the time for me. Backing up in-situ webbing is usually simple and quick; it isn't always easy or possible to back up the entire anchor with an independent anchor point.

It is perhaps worth mentioning that with just a tiny bit of ingenuity, the climbing rope can be used to back up slings for the first person down, something that is useful if the slings in question are very long and the party doesn't have anything that will work.

When climbing routes in which the second carries a pack, I've always had twenty feet of 1/2 inch or so webbing and a few descending rings. If the pack is at the base of a route that is 400 feet or less, the extra slingage usually stays there---at worst, we can tie our two half-ropes together and make it back to the pack from the top to retrieve the slings if they are needed.

The situation I haven't attended to appropriately is when no pack is carried and there is none at the base, or the base is too far to reach from the top. Here it seems to me that it makes sense to wrap up my twenty feet of sling and the few rap rings and carry it on the harness like the cordelette I almost never use, or, alternatively, just carry the 6mm cordelette that mostly naps in my pack.

I think having stuff with you for rap anchors matters---it affects the psychology of evaluating what is in place. If you are going to have to cut up and knot sewn climbing slings (triple fisherman's for dyneema please!), I think you are less likely to back up anchors that might be a little questionable.
Ed Hartouni

Trad climber
Livermore, CA
Jan 14, 2013 - 09:07am PT
I always test my system before undoing my redundant connection to the anchors, with full body weight and usually a bit of bouncing.

This is something that I try to do for every rap, to make sure I've threaded the rope properly through the rap device, that the anchor is secure (though usually I'm connected to the anchor, and a test to failure of the anchor wouldn't be a good thing). Even after I've put a brand new sling on...

I'm sure I don't always do this... but it is a part of my ritual... as Jim says, rappelling is one of the more dangerous things we do...

I've been working on making sure I have some sort of backup on rappel too, but haven't developed a consistent habit of employing a backup on rappels. It's a bad habit not to, but my training is difficult to overcome.

As for understanding the weathering process on nylon, I would imagine that the process is difficult to specify when the exposure conditions are unknown. Any assumptions I would make would leave a very large uncertainty in the conclusion, and if I'm down that path in my thought, it's because I have some doubt regarding the integrity of the anchor... I use that doubt as a trigger to replace the slings, plain and simple.

However, that is a judgement call, and as the OP points out, it is not so difficult to exhibit poor judgement.

Once again, I am very happy the outcome of this event has resulted in a thread which invites analysis of that judgement and not one where we are trying to understand the cause of a tragedy.

High Fructose Corn Spirit

Gym climber
-A race of corn eaters
Jan 14, 2013 - 09:17am PT
the sling can hold 500 lbs for 5 seconds and your testing uses up about 3 seconds of that

What does this mean? Can anyone tell me? To me, it points to a lack of savvy regarding a rappel system and how its parts work esp in terms of functionality, forces and failure.

I've never bounce-tested a rap anchor and don't imagine I ever would

This is certainly a disturbing remark from someone so experienced. Esp concerning something so basic to the sport of climbing.

.....

Then, also, we have all this talk about replacing old webbing (which goes without saying, really, when it's called for, so why is it even an issue), well the same philos about testing the system also applies to top rope anchors with suspect bolts. If you're in the backcountry, for example, and you encounter a questionable anchor, you're not necessarily in position to go out of your way to replace a questionable rap anchor or top rope anchor of whatever makeup. So what do you do under many circumstances? You stand below it and bounce test it while backed up by something else. I've done this hundreds of times over my climbing history. Along similar lines, when I'm at a crag and encounter a questionable anchor for TR, say, which might amount to simply an unknown anchor, history-wise, say, I'll bounce test it when I'm near the ground for both myself or the group as the case may be for the ensuing top rope session (which we can imagine might last hours). This should all be Rappel Basics 101 or Top Rope Basics 101. For everybody who cares about safety.

Insofar as it isn't, no wonder many shirk rappelling. While others love it.

.....

Other points have been made, too, regarding anchors that are suspect, which aren't really of any issue; instead, it's all just Rap 101. For instance, (1) sending the heaviest down first while he is backed up; (2) providing a fireman's belay at every opportunity (though not an anchor issue) just a backup safety issue that often requires no extra effort.



Maybe we should add the obvious: If one is considering a rap at a suspect anchor of any sort that (a) cannot be backed up for testing and (b) is hanging or thereabouts, whose failure would spell a fall, then he should NOT bounce test it (which can subject the system to many g's). But thankfully I think the majority of climbers understand this point.

Finally(?), testing also tests more than just the slings.
One of the goals is to uncover unobserved flaws in the anchor system.
So I believe testing is still quite useful in the real world.

Yes, indeed.
JLP

Social climber
The internet
Jan 14, 2013 - 10:56am PT
JLP--I posted a link and a quote from the BD QC Archive that might well have been what Jim remembered.

The one I'm recalling was much more broad and tested many more samples. Some of those samples were the tester's own that they dated and later tested - possibly a few years later. This test was linked to and talked about on these forums for quite some time. The biggest surprise and most of the discussion was about the weakness of Spectra after UV damage. It was defintitely before 2005, possibly long before. Maybe I'll search for it at some point.

rgold

Trad climber
Poughkeepsie, NY
Jan 14, 2013 - 11:01am PT
This is certainly a disturbing remark from someone so experienced. Esp concerning something so basic to the sport of climbing.

The remark in question is about not bounce-testing rap anchors. I might have added that I've never climbed with anyone who bounce-tests them either, and over 56 years I've climbed with a lot of experienced climbers. Maybe I'm just climbing with the wrong folks. Who here regularly bounce-tests their rap anchors?

I guess the main problem with bounce-testing is that it is total folly without an independent back-up anchor that is good enough to hold a short fall on static material, and such anchors are not always available or may require time and effort to rig---they will have to be good enough for considerably higher loads than the rap anchor requires.

As I've said, I almost always back up the slings, even pretty new-looking ones, with an independent sling for all but the last person down, so the initial raps do constitute a substantial and realistic test of the sling integrity. I almost never rappel on a single sling without installing another one for redundancy. If it is easy to rig an independent anchor or if it isn't but the rap anchor itself appears dodgy to me, than I'll install the extra anchor and, once again, let the first rappeller(s) constitute the rap anchor test.

I might add that I always test the set up of the rappelling device with a bodyweight test and small jerk while still tethered to the anchor as Ed mentions, but of course this test already assumes the slings and anchor are adequate and does not seem to me to be germane to the present discussion.
Don Paul

Big Wall climber
Colombia, South America
Jan 14, 2013 - 11:10am PT
understanding the weathering process on nylon

I wonder if a better material is available. According to what I'm reading on the internet, Dacron/polyester has the best UV resistance of all fiber types and is used to support antennas. Also, I notice that these dacron ropes are colored black, I wonder if the color makes a difference? If so then just using black nylon slings might help.

http://www.k1cra.com/catalog/product.aspx?productID=2144
High Fructose Corn Spirit

Gym climber
-A race of corn eaters
Jan 14, 2013 - 11:20am PT
I might have added that I've never climbed with anyone who bounce-tests them either, and over 56 years I've climbed with a lot of experienced climbers. Maybe I'm just climbing with the wrong folks. Who here regularly bounce-tests their rap anchors?

Well, if we're going to have a valid, accurate and meaningful discussion then let's make sure we're framing it right.

a) Who here regularly bounce-tests their rap anchors?
b) Who here regularly bounce-tests their highly suspect rap anchors when conditions or cirumstances, like an available ledge, allow it?

Here, I think you're likely to get different answers to the two questions.

I'll start: (a) Seldom. (b) Always.

Your post drew my attention for suggesting that there is never a reason to bounce-test by your comment... "I've never bounce-tested a rap anchor and don't imagine I ever would..." Further, the concluding "unless" part seemed to me to minimize the importance of this valuable safety protocol.

The rest of your posts I agree with.
rgold

Trad climber
Poughkeepsie, NY
Jan 14, 2013 - 11:26am PT
Hmm. If I had a highly suspect rap anchor that I couldn't just replace with a better one and a comfy ledge to test it from, I'd bounce test it too, so I should retract my inability to imagine more than one circumstance. However, that particular combination of good and bad circumstances has never arisen for me. Whenever I've been confronted with a highly suspect anchor (as opposed to just the slings) I've always managed to build a much better one somewhere in the vicinity (or even, in one or two cases, not really in the vicinity).

I should also confess to a period of building and convincing my partners to rely on some sketchy anchors. Back in the day when we still had hammers, I used to be fond of hammering rocks into cracks---creating unnaturally wedged chockstones---and slinging them for rappels. This was before nuts came on the scene and we became more sophisticated about wedging things into cracks. What worries me in retrospect about those hammered chockstones is the possibility that the hammering might have cracked them.
High Fructose Corn Spirit

Gym climber
-A race of corn eaters
Jan 14, 2013 - 11:37am PT
That particular combination of good and bad circumstances has never arisen for me.

Really? Well, this is surprising. This difference in experience then might explain our hangup on this thread.

There are several wide-open aging crags in my area that have literally dozens of suspect rap or tr stations featuring a ledge, a semi-ledge, or even a top where it permits me, and behooves me, for safety sake to bounce-test them (but true, more often just to jerk-test them) before they earn my trust to use.

And, to add, then when I have rapped on these suspects or unknowns (maybe they're two old rusty quarter inchers, say, set 25 years ago by who knows), I try to be Mr. Smooth about it and give all my attention to not shocking the system (say, with more than 1.5 g or so).

So far no issues. Knock on rock.
10b4me

Boulder climber
Somewhere on 395
Jan 14, 2013 - 12:05pm PT
Who here regularly bounce-tests their rap anchors?

not me.

what my partner and I did was to place a piece as a backup. first guy raps, if the primary piece didn't move, or the rock was solid. it was all good. the second cleans the backup piece, raps, and everybody is happy.
Jeremy Ross

Gym climber
Jan 14, 2013 - 02:52pm PT
are you in the camp with moosedrooler such that you never question anything once it gets into a "respectable" publication?


Every scientist worth his/her weight will question any article in any publication for methods used, conclusions, data, etc. Tony, your recent posts about scientific journals in various threads leads me to believe you neither understand the scientific method nor the method of reading/analyzing/deconstructing/understanding a peer reviewed journal.



-JR
mission

Social climber
boulder,co
Jan 14, 2013 - 09:25pm PT
Don't they have some sh#t you can smoke that will make you more paranoid?
Dingus Milktoast

Gym climber
And every fool knows, a dog needs a home, and...
Jan 14, 2013 - 09:40pm PT
Blah blah blah blah seconds this blah blah blah seconds that the sling broke under body weight.

Body weight.

Jackasses. Just another completely useless technonerd discussion, a great sound and fury signifying nothing.

Body weight.... (sheesh)

DMT
Tony Bird

climber
Northridge, CA
Jan 15, 2013 - 06:14am PT
^^^ what dingus said ...

except that our dear and glorious donini continues to decline to cite the article which he himself mentions in the OP, whilst doniniolaters try to cover for him by guessing which article it was.

amen to sheesh. much like vatican city, where an industry of casuists occludes an inaccessible library. (i hope this is all big-headed enough for locker.)
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