Author Topic: CNCC resin anchor scheme (split from "Car Pot anchors" topic)  (Read 2496 times)

Offline droid

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Re: CNCC resin anchor scheme (split from "Car Pot anchors" topic)
« Reply #50 on: January 09, 2017, 08:38:23 pm »
Adopt Kenilworth's conservation-minded idea of not going down caves and the problem (if it exists) disappears....
No longer 'Exceptionally antagonistic' 'Deliberately inflammatory'

Offline owd git

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Re: CNCC resin anchor scheme (split from "Car Pot anchors" topic)
« Reply #51 on: January 09, 2017, 08:49:34 pm »
I, for one found your post refreshing Mike. Thanks for putting your head above the parapet, or whatever.
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Offline Chocolate fireguard

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Re: CNCC resin anchor scheme (split from "Car Pot anchors" topic)
« Reply #52 on: January 09, 2017, 09:16:06 pm »


I expect Simon may be dead right about the IC anchor being better in various ways than all the other anchors. But does it matter? Is our objective to design the perfect bolt, or to find a practical option for long-lasting anchors?

If I was one of the people in BCA who have to decide what anchors should be used, and put that in writing for all to see, I wouldn't know whether to laugh or cry at this point.

Quite apart from wanting to do the best job I could when making such an important decision, I would be very aware that it has been many years since "OK, that's fair enough, it may not have been the best bolt but it was a good practical option" is something likely to be said by relatives of a caver who has sustained life-changing injuries as a result of bolt failure.

Quite apart from the human consequences of such an accident I suspect that the BCA insurance scheme could not stand many hits of the likely size, and then where would we be?


Offline topcat

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Re: CNCC resin anchor scheme (split from "Car Pot anchors" topic)
« Reply #53 on: January 09, 2017, 09:23:45 pm »
Mike, where I've used Rainox 'spits' I've left a s/s hanger in place too.  Like spits, the Rainox threads can still get gritted-up.

I've not seen figures, but feel they might not have the same holding power of a trad spit on account of only a 2 way rather than 4 way split/expansion.

But whatever, they won't match a resin anchor for strength.

But then again, they are not the weakest link in the chain: your jammers are, by a long shot.

Offline Bob Mehew

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Re: CNCC resin anchor scheme (split from "Car Pot anchors" topic)
« Reply #54 on: January 09, 2017, 09:28:41 pm »
I get the sense that the idea behind the bolts (note I am talking about bolting caves that people other than the initial explorers go in) is that you do it once, you do it using the best gear you can, and when that anchor fails / needs replacing it can be easily pulled and the same location used for a replacement - thus minimising the impact in the cave.

Not sure how this applies to things like the Rainoxes mind.  Might seem like trying for perfection but it does mean we avoid a proliferation of random old bolts and spits everytime we need a new one.

Thank you for your summary. 

As topcat alludes to, the problem with spits was that given cavers were mean, they took the hanger away with them.  So every trip required a bolt and hanger to be inserted.  In some places that would mean several times a weekend.  Inevitably they wore out.

I have not seen any test results for Rainox and can't immediately recall one for a spit but would guess they are limited by the hanger which usually tears at just above 25kN, its rated capacity.     


   

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Re: CNCC resin anchor scheme (split from "Car Pot anchors" topic)
« Reply #55 on: January 09, 2017, 10:04:16 pm »
I expect Simon may be dead right about the IC anchor being better in various ways than all the other anchors. But does it matter? Is our objective to design the perfect bolt, or to find a practical option for long-lasting anchors?

Bob said that concern about "chloride stress corrosion cracking" (i.e. corrosion from salt water) has made the CNCC and others reject all anchors except those made from a particular type of stainless steel, drastically limiting the options. But surely this is only relevant to anchors placed near the sea? Why would you need "salt water proof" anchors in the Dales?

Is this symptomatic of the thinking around this topic? Are excellent existing products being rejected because they are not 100% theoretically perfect?


When I read this thread at lunch time today, I was heading towards exactly this conclusion. Do our anchors need to be better than those generally sold by well respected manufacturers and exceed the usual ratings? This appears to come down to the issue of 316 stainless steel, which the CNCC have minuted was recommended over 304 by Hilti, DMM and Lyon (http://cncc.org.uk/doc/55), and having read that I can fully understand a reluctance to go against that recommendation.

Having said that, there's a balance to be struck. If a reliable affordable source of suitable 316 anchors is not forthcoming, it seems ridiculous to avoid improving the current safety of caves on the basis that we don't yet have the ideal solution.

Offline Simon Wilson

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Re: CNCC resin anchor scheme (split from "Car Pot anchors" topic)
« Reply #56 on: January 09, 2017, 11:09:51 pm »
I expect Simon may be dead right about the IC anchor being better in various ways than all the other anchors. But does it matter? Is our objective to design the perfect bolt, or to find a practical option for long-lasting anchors?

Bob said that concern about "chloride stress corrosion cracking" (i.e. corrosion from salt water) has made the CNCC and others reject all anchors except those made from a particular type of stainless steel, drastically limiting the options. But surely this is only relevant to anchors placed near the sea? Why would you need "salt water proof" anchors in the Dales?

Is this symptomatic of the thinking around this topic? Are excellent existing products being rejected because they are not 100% theoretically perfect?


When I read this thread at lunch time today, I was heading towards exactly this conclusion. Do our anchors need to be better than those generally sold by well respected manufacturers and exceed the usual ratings? This appears to come down to the issue of 316 stainless steel, which the CNCC have minuted was recommended over 304 by Hilti, DMM and Lyon (http://cncc.org.uk/doc/55), and having read that I can fully understand a reluctance to go against that recommendation.

Having said that, there's a balance to be struck. If a reliable affordable source of suitable 316 anchors is not forthcoming, it seems ridiculous to avoid improving the current safety of caves on the basis that we don't yet have the ideal solution.


The BCA Equipment and Techniques Committee are ahead of you on this debate. However, I am certain that others with far more experience than me on the committee will agree (because they have said so) that the committee would benefit from more input from knowledgeable people and very much welcome more people getting involved.

Offline Hammy

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Re: CNCC resin anchor scheme (split from "Car Pot anchors" topic)
« Reply #57 on: January 09, 2017, 11:33:11 pm »
Could somebody explain what is wrong with the Raumer Superstar anchor?

Offline Mike Hopley

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Re: CNCC resin anchor scheme (split from "Car Pot anchors" topic)
« Reply #58 on: January 09, 2017, 11:48:51 pm »
Quote
As topcat alludes to, the problem with spits was that given cavers were mean, they took the hanger away with them.  So every trip required a bolt and hanger to be inserted.  In some places that would mean several times a weekend.  Inevitably they wore out.

Thanks for clarifying the fundamental problem with spit-type anchors (including Rainoxes). That makes perfect sense. In the context we were using them, that particular problem wasn't likely to ever show itself. It seems obvious now you've said it!

I hope I haven't distracted too much from the relevant discussion of resin anchors by mentioning Rainoxes. I was just curious; thanks for your patience! :)


Quote
Quite apart from wanting to do the best job I could when making such an important decision, I would be very aware that it has been many years since "OK, that's fair enough, it may not have been the best bolt but it was a good practical option" is something likely to be said by relatives of a caver who has sustained life-changing injuries as a result of bolt failure.

I feel a bit heartless for saying this, but surely the "someone might die" argument can always be ratcheted up another notch of theoretically improved safety. But how much does it genuinely increase safety to do so?

Relative strength of anchors is largely a non-issue when the weakest link in the safety chain is the rope-ascender interface (about 4 -- 6 kN). It doesn't matter how strong your resin anchor is when your jammer destroys the rope.

What about security/reliability of anchors? Sensible rigging requires that, if any one anchor should fail at the worst possible time, the caver will remain safe and will certainly not suffer any serious injuries. In the case of resin anchors especially, the probability of a single (correctly installed) anchor failing is extremely low.

Let's say that the chance of one resin bolt failing on a given use is about 1/10,000. Then the chance of two failing at the same time is about 1/100 million. That figure is probably far too pessimistic. My actual guess would be closer to 1/100,000 for one resin anchor, giving 1/10 billion chance for simultaneous failure of two resins.

Of course there are specific situations where multiple simultaneous anchor failure is a real danger. For example, we know that multiple resins have failed together in highly corrosive sea environments. We also know that anchors installed right next to each other are dependent: if one fails, it may cause the other to fail. (Do we know of any other possibilities?)

And of course my hand-waving figures can be debated. But how many resin anchor failures do we even know about, other than those in seaside areas due to salt-water corrosion? Even with spits, anchor failure is rare.

Sadly, there are still plenty of serious accidents in caving. I hear about (and know) people who abseiled off the end of a rope. I hear about (and know) people who lost control of an abseil and hit the deck. I hear about (and know) people who fell off an electron ladder without a lifeline. I hear about (and know) people who were hit by falling rocks. I hear about (and knew) people who drowned.

Some of these people got away with minor injuries. Some of them were seriously affected. Some are dead.

I don't hear about, or know, anyone who has been injured from two bolts failing at the same time. And there are a lot of people who have done a lot of caving on some really grotty bolts.

That is not to say that we should accept poor bolts. The resin anchors installed in the UK are superb, and everyone involved deserves our thanks. The IC anchors look excellent too and I hope the project succeeds and makes the whole topic moot. But when all commercially available products have been rejected because they are imperfect, I wonder whether we've lost perspective.

Yet equally I recognise that I know far, far less about the subject than the people involved. Perhaps I place too much faith in commercial anchors. I suppose when you're used to hanging off rather shocking-looking anchors -- I recall an ancient heavy-duty pair that appeared to have become mostly gel, which was rather alarming to see just after flinging yourself over the knife-edge pitch head balcony -- then any kind of resin feels like an enormous luxury. ;)

For myself, I'm grateful for the splendid P-bolts that I use. I'm also happy to use existing Spits, especially when there are not enough P-bolts to ensure safety; there are many cases where the rigging becomes safer by using one. And in the spirit of cooperation and respect, I refrain from adding anchors even when I know there aren't truly enough of them to rig perfectly.
« Last Edit: January 10, 2017, 12:12:20 am by Mike Hopley »

Offline adam

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Re: CNCC resin anchor scheme (split from "Car Pot anchors" topic)
« Reply #59 on: January 10, 2017, 01:47:48 am »
Of course there are specific situations where multiple simultaneous anchor failure is a real danger. For example, we know that multiple resins have failed together in highly corrosive sea environments. We also know that anchors installed right next to each other are dependent: if one fails, it may cause the other to fail. (Do we know of any other possibilities?)

There's also the likelihood that anchors installed next to each other will be from the same batch, use the same tube of resin and have been installed by the same person - all of which means that one failure increases the chance of a second. The greatest unknown though is the rock the anchors are placed in, which is much more variable (and therefore prone to failure) than the anchors or resin. This also makes simultaneous anchor failure more likely, as the rock is likely to be of similar quality in the same area.

None of the above is unique to resin anchors; you could say the same for spits or throughbolts or anything else. The training and experience of installers helps prevent poor placement of resin anchors, but this becomes difficult when there is spit rash to contend with. Spits will usually be placed in the best place for them i.e. good rock, good rope hang - which would also be the best place for a resin anchor. When space is limited, even one set of spits could make finding suitable resin anchor sites challenging. When there are multiple sets, the problem is compounded.

Offline Bob Mehew

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Re: CNCC resin anchor scheme (split from "Car Pot anchors" topic)
« Reply #60 on: January 10, 2017, 09:35:42 am »
Could somebody explain what is wrong with the Raumer Superstar anchor?
I had not spotted they were 316 but there is a weld which could put in stress which raises the chloride stress corrosion cracking concern.  Thanks for identifying them.

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Offline Bob Mehew

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Re: CNCC resin anchor scheme (split from "Car Pot anchors" topic)
« Reply #62 on: January 10, 2017, 11:37:53 am »

Offline Madness

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Re: CNCC resin anchor scheme (split from "Car Pot anchors" topic)
« Reply #63 on: January 10, 2017, 12:17:26 pm »
Not suitable for every anchor location (direction of pull), but a simple length of 10mm 316 Stainless threaded bar resined into the rock and then fitted with a stainless hanger and a stainless flat washer and nyloc nut (all 316 grade) could be an option. There's a risk that the hangers could be stolen, but a don't thinks any true caver would do that.

Offline MJenkinson

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Re: CNCC resin anchor scheme (split from "Car Pot anchors" topic)
« Reply #64 on: January 10, 2017, 12:18:19 pm »
Bob - has anyone ever got a quote for commercial production of the IC anchors? Say a batch of 200?

Offline Madness

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Re: CNCC resin anchor scheme (split from "Car Pot anchors" topic)
« Reply #65 on: January 10, 2017, 12:41:20 pm »
Bob - has anyone ever got a quote for commercial production of the IC anchors? Say a batch of 200?

Taking a commmon size of plate (3000mm x 1500mm). If the IC Anchor used an area of 150mm x 50mm that would equate to 600 per sheet of plate. Full use of the plate would give a logical batch size. No manufacturer would want to end up with a off-cut of material that they may never use again. Laser profiling is quite expensive due to the overhead recovery rates that companies charge. CNC Laser Profiling machines are not cheap and companies need to recover their investment.

Simon has done a great job in developing this anchor. The key now is to make the manufacture of them as economically viable as possible. Then we need to fund the manufacture and installation of them.

In all honesty there's a limited market for any type of anchor, so they're never going to be available for pennies.

As cavers, we shouldn't take it for granted that the caves we visit will be fitted with good anchors, paid for by someone else. We all need to put out hands in our pockets and contribute.


Offline Bob Mehew

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Re: CNCC resin anchor scheme (split from "Car Pot anchors" topic)
« Reply #66 on: January 10, 2017, 02:31:56 pm »
There's a risk that the hangers could be stolen, but a don't thinks any true caver would do that.

Your faith is touching.  Read http://ukcaving.com/board/index.php?topic=20753.msg266486#msg266486 .   :(

Online andrewmc

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Re: CNCC resin anchor scheme (split from "Car Pot anchors" topic)
« Reply #67 on: January 10, 2017, 04:58:24 pm »
Could somebody explain what is wrong with the Raumer Superstar anchor?
I had not spotted they were 316 but there is a weld which could put in stress which raises the chloride stress corrosion cracking concern.  Thanks for identifying them.

I'm with you on the weld but this is (I know I've said this before) the SCC that has never been observed in the UK on the tens or hundreds of thousands of climbing bolts, lots of which are 304, installed on sea cliffs around the country? :)

I guess my questions are:
a) does anyone actually think that say the Raumer anchor is not good enough (i.e. if the approved anchors didn't exist, would these anchors remain unapproved)?
b) if there is a supply issue with the IC anchors, is it better to wait rather than use alternative anchors?

The skill and attention of the installer (mixing the resin right, keeping a sample, blowing out the holes properly, putting bolts in independent pieces of solid rock) is way more important than what bit of metal goes in a hole.

Offline owd git

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Re: CNCC resin anchor scheme (split from "Car Pot anchors" topic)
« Reply #68 on: January 10, 2017, 06:32:44 pm »
See the post on Rowter hole/ peak district and weep!!!!. :clap2: :clap2: :thumbsup: :tease:
I had no envolvement in the job but hope to 'ave a look .
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Offline MJenkinson

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Re: CNCC resin anchor scheme (split from "Car Pot anchors" topic)
« Reply #69 on: January 10, 2017, 06:36:49 pm »
See the post on Rowter hole/ peak district and weep!!!!. :clap2: :clap2: :thumbsup: :tease:
I had no envolvement in the job but hope to 'ave a look .

May I be so bold as to enquire as to who funded the bolts for Rowter - the team?

Offline nickwilliams

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Re: CNCC resin anchor scheme (split from "Car Pot anchors" topic)
« Reply #70 on: January 10, 2017, 06:44:27 pm »
The bolts for Rowter were funded by BCA, as were the resin and the equiment used to place them.
"Economics is simply the branch of sociology that deals with people trading items and the fact that they use more numbers does not make it anymore of a science."

Offline Simon Wilson

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Re: CNCC resin anchor scheme (split from "Car Pot anchors" topic)
« Reply #71 on: January 11, 2017, 01:12:05 am »
See the post on Rowter hole/ peak district and weep!!!!. :clap2: :clap2: :thumbsup: :tease:
I had no envolvement in the job but hope to 'ave a look .

I usually ignore Old Git's postings because he talks in riddles and whatever he intends, I don't get.

Old Git, what has Rowter Hole got to do with this thread? Weep about what? WTF are you on about now?

Offline owd git

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Re: CNCC resin anchor scheme (split from "Car Pot anchors" topic)
« Reply #72 on: January 12, 2017, 03:49:40 pm »
Alex would seem to have worked it out on the Rowter thread Simon  ;)
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Online MarkS

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Re: CNCC resin anchor scheme (split from "Car Pot anchors" topic)
« Reply #73 on: January 12, 2017, 04:13:33 pm »
I believe that the IC anchor and BP anchor are both endorsed by the BCA so in principle either/both could be used by the CNCC and the DCA. The CNCC has endorsed the IC anchor as its preferred anchor over the BP anchor on conservation grounds, but the DCA do not currently install IC anchors. Perhaps someone directly involved in the BCA/DCA/CNCC can confirm that.

This thread seems to be largely about options that match the IC anchor performance in terms of strength, longevity and conservation, and about whether the characteristics of IC anchors are really required. The IC anchor vs. BP anchor seems a slightly different debate.
« Last Edit: January 12, 2017, 04:33:48 pm by MarkS »