/ Tat - what thickness can you get away with / knot?

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Rob Halliday - on 02 Jun 2014
All,

Hoping someone can help. Heading to the Cuillins / Skye for a climbing trip and need to buy some tat/chord for setting up abseils. What thickness of chord can you get away with? Also assume double fishermans is a suitable knot?

Any guidance would be much appreciated!

Cheers,

Rob
Coel Hellier - on 02 Jun 2014
In reply to Rob Halliday:

Most people go for about 6mm perlon cord. A double fishermans is fine for cord, or use a tape knot for tape.
CurlyStevo - on 02 Jun 2014
In reply to Rob Halliday:

I've abbed off 5mm before now but if buying for purpose id get 6mm unless weight was a big issue. Generally I use what I have spare at home.
Rob Halliday - on 02 Jun 2014
In reply to Coel Hellier:

Cheers - thanks both
aultguish on 02 Jun 2014
In reply to Rob Halliday:

Remember that Gabbro is quite rough and abrasive, so you'll want to take that into account, especially if you have a load of people in your party heading off down the abseil.
Rob Halliday - on 02 Jun 2014
In reply to aultguish:

Good shout. Thanks.
Rob Halliday - on 02 Jun 2014
In reply to Rob Halliday:

Just had another thought as well. Would 6mm do for using as a cordelette / threads etc when setting up an anchor?
Coel Hellier - on 02 Jun 2014
In reply to Rob Halliday:

6mm perlon is rated to about 7 to 8 kN, which is about what a big fall can generate. In almost all cases that would be fine, but if you were going to take a fall-factor-2 onto a multipitch belay then it likely wouldn't be. For belays the strength-to-weight of dyneema slings is likely a better bet.
IPPurewater on 02 Jun 2014
In reply to Coel Hellier:

Also if you have 50m+ double ropes or a 60m+ single, you should have enough rope to belay without a cordalette on most routes in the UK.
Nath93 - on 02 Jun 2014
In reply to IPPurewater:

As long as you are swinging leads and letting your partner take the next pitch. Cordallette is good for equalising lots of different bits when your other big sling is in the belay below or you are leading through the next pitch as well/
IPPurewater on 02 Jun 2014
In reply to Nath93:
Yes, I know how they are used.

They are usually un-necessary in my opinion.
Post edited at 23:04
Nath93 - on 02 Jun 2014
In reply to IPPurewater:

Why do you find them un-necessary?

I don't mind building belays from rope as long as I am alternating leads but sometimes I end up out with less experienced people so find that if I put in a few bits of gear for my belays, which keeps them happier, then even a 240cm sling can't equalise all points safely. Other than the rope and using various slings I just go with the cordallette, means I can use guide mode as well if need be.
abseil on 03 Jun 2014
In reply to Rob Halliday:

My wisdom is, for goodness sakes err on the side of caution for all abseils. Sorry to be blunt but have you ever seen, or heard of, the results of abseiling accidents? I have (both).

Again, sorry to be blunt and upset people but. Again. I have seen the results myself.
CurlyStevo - on 03 Jun 2014
In reply to Coel Hellier:
Even 7mm is a bit weak for a cordelette if you intend to make a snake one as the knots weaken it quite a bit. It would be fine as a closed loop as these are twice as strong.

What routes were you thinking of using it on and would you be swinging leads?
Post edited at 10:24
Coel Hellier - on 03 Jun 2014
In reply to Nath93:

> if I put in a few bits of gear for my belays, which keeps them happier, then even a 240cm sling can't equalise all points safely.

The idea of equalising all the points is a bit over-rated. For starters, equalisation will only work for a pull in one particular direction. If you're using static cord then the pull will almost inevitably by primarily on one piece at a time. Second, if you have multiple bits then equalisation will likely be unnecessary in that the belay will be solid enough anyhow.

An exception could be where you have lots of pieces, all of them dubious, and where you can predict the direction of pull, but that would be rare. Most of the time faffing with equalisation is simply unnecessary hassle.
The Ex-Engineer - on 03 Jun 2014
In reply to Nath93:
> sometimes I end up out with less experienced people so find that if I put in a few bits of gear for my belays, which keeps them happier, then even a 240cm sling can't equalise all points safely.

That is very poor approach IMO. On the vast majority of stances on easy routes in the UK routes you need no more than two bomber runners. Placing more is both pointless, time consuming and crucially sets a very bad example to novices. The crucial point in trad climbing is that the quality of anchors is everything, quantity counts for absolutely nothing. Suggesting otherwise (even implicitly) by equating more gear with a BETTER belay is not something I would consider particularly sensible.

In fact I would go as far as to say that if I ever need to place 3 anchors for a belay when climbing with novices, I'm either missing something, belaying in the wrong place or I've potentially made a poor route choice in the first place.
Fraser on 03 Jun 2014
In reply to The Ex-Engineer:

> That is very poor approach IMO. On the vast majority of stances on easy routes in the UK routes you need no more than two bomber runners. Placing more is both pointless, time consuming and crucially sets a very bad example to novices. The crucial point in trad climbing is that the quality of anchors is everything, quantity counts for absolutely nothing. Suggesting otherwise (even implicitly) by equating more gear with a BETTER belay is not something I would consider particularly sensible.

I think quite a few folk on here would disagree with you on that. btw, what's your definition of an 'easy route' in this context?
The Ex-Engineer - on 03 Jun 2014
In reply to Coel Hellier:
> Second, if you have multiple bits then equalisation will likely be unnecessary in that the belay will be solid enough anyhow.

That is not necessarily true. See the accident report below for a clear example of how FOUR belay anchors failed when they were not rigged in the normal textbook manner.

> Most of the time faffing with equalisation is simply unnecessary hassle.

I am confused. Any safe belay I'd be happy with would be pretty much identical to one that would be described as 'equalised'.

You are completely correct in that equalisation, per se, is never particularly effective in terms of sharing out the forces. However that is fairly irrelevant as having "no extension" in belay anchors is the far more important basic principle.

In practice, achieving "no extension" (or at least minimal extension) is pretty much indistinguishable from equalising the anchors. As such, going through the process of equalisation is generally sensible and worthwhile.

Have a read of http://www.traditionalmountaineering.org/Report_Washington_Seyler.htm.
The Ex-Engineer - on 03 Jun 2014
In reply to Fraser:
> I think quite a few folk on here would disagree with you on that.

Disagree with what exactly?

I offered two opinions (admittedly both saying something fairly similar) and effectively made five factual statements.

Fraser on 03 Jun 2014
In reply to The Ex-Engineer:

> Disagree with what exactly?

The paragraph I quoted.

And again I'd ask, what would you consider an "easy route" in this context?
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Bilbo on 03 Jun 2014
In reply to Rob Halliday:

> Hoping someone can help. Heading to the Cuillins / Skye for a climbing trip and need to buy some tat/chord for setting up abseils. What thickness of chord can you get away with? Also assume double fishermans is a suitable knot?
> Any guidance would be much appreciated!
> Cheers,
> Rob

Nothing less than 6mm cord for abseils and rope is better still. Best not think in terms of "get away with" you'll probably only make a mistake with abseiling once! The peace of mind gained from the extra safety margin will be worth every single one of the few extra grammes you'll need to carry in fatter abseil tat. Have fun :-)
Coel Hellier - on 03 Jun 2014
In reply to The Ex-Engineer:

> See the accident report below for a clear example of how FOUR belay anchors failed when they were not rigged in the normal textbook manner.

If I understand that report, they took a fall-factor-2 fall that ripped the main belay, mostly as a result of the rock being low quality such that the 3 runners and 4 main belay nuts just destroyed the rock and pulled. This seems to me to come under my qualification: "An exception could be where you have lots of pieces, all of them dubious, ...", where I agree with you on equalisation as far as possible.
Offwidth - on 03 Jun 2014
In reply to The Ex-Engineer:
Well said. Its amazing on easier routes how people think extra gear makes things safer when it often increases risk (through possible mistakes in over complication or through focussing too much on other issues, or by using gear you may need above). Sometimes on a good ledge and a bomber piece (like a big tree) even the one belay piece is fine. Multi pitch belays on harder routes can need more pieces at times for the obvious reasons (to protect agaimst upward pulls, to protect a belay with a bold section immediately above, poor rock etc) plus the odd exceptional easier route like Crescent Climb that has shit rock for the belay before the crescent.
Post edited at 15:35
nclarey - on 03 Jun 2014
In reply to Coel Hellier:

I think the other key thing from that report was a 120 degree "anchor equalisation" which is arguably more multiplication than equalisation :-)
purplemonkeyelephant - on 03 Jun 2014
In reply to The Ex-Engineer:

If your gear placements are so bomber why not just use 1? I agree with your overall sentiment, but to say 3 pieces is excessive is a bit presumptuous. The very nature of climbing means that you won't always have textbook bomber placements on every pitch around the world for the rest of your life. With three, if one somehow fails you still have two. With two, if one fails your life is hanging on that single piece.
CurlyStevo - on 03 Jun 2014
In reply to purplemonkeyelephant:
Personally I like some redundancy in a belay especially for multi pitch. Even if I have a bomber anchor ideally I'll back it up. For me if I have two good placements or one very good and an ok one two belay anchors is fine. However if I can't get this I'll keep adding more. I think I've placed 5 a couple of times when either the placements are small nuts or the rock quality is a bit dubious. Generally if I can't find something I don't mind climbing quite high up the next pitch to get a solid anchor.

Swanage is an interesting one as quite often the placements are good but it's very hard to assess how well the rock is attached to the main face. So I'll only rely on two anchors if the placements are good AND the rock is clearly not going to fail. Even quite large sections can be of dubious quality and many of the belays are on the mid way fault which often has very poor rock in the fault and increasingly poor rock as you approach the fault sometimes for several meters. Also the rock above the fault is sometimes pretty loose to the top! If the gear is in blocky rock of medium size I also try and make sure that more than one piece of rock would need to move for the belay to fail!
Post edited at 20:01
The Ex-Engineer - on 03 Jun 2014
In reply to purplemonkeyelephant:
> If your gear placements are so bomber why not just use 1?

I do regularly.

I rarely back up natural belay anchors; large spikes, boulders, threads, chocks or trees. On good stances I'll sometimes use a single large hex. I rarely ever use multiple anchors when scrambling or on easier Alpine or Winter routes.

> The very nature of climbing means that you won't always have textbook bomber placements on every pitch around the world for the rest of your life. With three, if one somehow fails you still have two. With two, if one fails your life is hanging on that single piece.

Comments like that don't really stand up to a rational analysis. They just make me think you (and others) don't really understand the mechanics of trad climbing.

In practice, belays anchors are several times LESS crucial than your runners. Belays are protected by your belay plate and (hanging belays excepted) by the belayer's own stance and inertia. Runners are not. Belays just need to hold 2-3kN in a worst case fall. Runners needs to hold around 5-8kN even in a moderate fall.

For a factor two fall to happen the leader generally needs to fall AND rip runners. If there is a high risk of both happening, then the leader has more important things to worry about than how many anchors to use in the belay. They either need to stick to easier routes or learn to place gear properly (or both).

Even if a factor two fall happens, worrying about the strength of the belay may be irrelevant unless the belayer is wearing gloves. If they aren't, the leader will very likely be dropped most of the rope length before the belay is even loaded.

Finally, if you are genuinely concerned about belay anchors not being good enough, adding an extra piece of gear is a poor mitigation strategy that is both time-consuming and reduces the gear available to the leader for the next pitch. The most effective option is switching to a body belay. It instantly doubles or triples your safety margin.

I do accept that placing extra gear may give a (misplaced) psychological boost to climbers operating in a stressful environment. However it is not justified by the facts. In reality, if a belay is not so poor as to convince you to body belay, then a 3rd anchor is probably unnecessary and a 4th or 5th anchor certainly will be.

[Hanging belays are a bit different but this whole discussion was based on comments about climbing on routes with less experienced partners where you will be leading every pitch.]
Nath93 - on 03 Jun 2014
In reply to The Ex-Engineer:

Fair points, well made.

Can I ask where you gather that kind of information? Would make interesting reading.
Tom V - on 03 Jun 2014
In reply to Rob Halliday:

By "tat" do you mean bits of rope/tape which you will be leaving behind after your abseil?
r0x0r.wolfo - on 03 Jun 2014
In reply to The Ex-Engineer

> Belays just need to hold 2-3kn in a worst case fall.

4mm cord shoule be fine then, right?
Joak - on 03 Jun 2014
In reply to Nath93:

> Fair points, well made.

> Can I ask where you gather that kind of information? Would make interesting reading.

Maybe a wild assumption on my part. Actual experience rather than from the pages of a book. I may be wrong.
jimtitt - on 04 Jun 2014
In reply to The Ex-Engineer:
> In practice, belays anchors are several times LESS crucial than your runners. Belays are protected by your belay plate and (hanging belays excepted) by the belayer's own stance and inertia. Runners are not. Belays just need to hold 2-3kN in a worst case fall. Runners needs to hold around 5-8kN even in a moderate fall.

The DAV who have tested a considerable number of belays over the years consider a minimum of 6kN for each piece to be required. I agree.
The weight of two climbers alone may be over 2kN.
Beginners should learn to build belays correctly and, they can decide to ignore this later when they have more experience, NOT be shown by their more experienced mate to build crap belays from the word go because the route is easy.
Post edited at 06:49
CurlyStevo - on 04 Jun 2014
In reply to The Ex-Engineer:
Your view is at odds with that of Libby Peters
http://www.ukclimbing.com/articles/page.php?id=2592
"some Gogarth belays require 5 or 6 pieces"
Also I reckon a modern plate on half ropes (say an ATC XP guide on 8.5 mm genesis) would be able to exert more than 3 kn on each rope (bd say it has 3 times the breaking force) so a factor two fall could easily reach max forces on the belay of around 6kn. At this level on some rock types (think adventure climbing) it can be hard to tell if anyone one piece could actually hold that (on rare occasions) and in these cases multiple pieces must be placed. If the spread of your pieces is fairly narrow placing more well equalised pieces will help to further distribute the load (of course if the spread is not narrow it may not help 'much' but atleast you are hedging your bets one of them will hold 6 kn).
Post edited at 07:18
SCrossley on 04 Jun 2014
In reply to The Ex-Engineer:

Whilst agreeing with most of what you say and find interesting could ask for clarification on this, please,

I rarely back up natural belay anchors;
large spikes, ------ Agree after a good shaking and kicking
boulders,----- Agree after a good shaking and kicking
threads,------ Depends, but I `m sure you meant that
chocks------ Now I would always try and back up a chock, even ones used for years can drop out unexpectedly
or trees ------- Agree after a good shake and a look at, though try not to damage the tree.
On good stances I'll sometimes use a single large hex -------now this I find interesting, why a large Hex and not a bomber No7 in a deep placement in Solid Rock, why specify a Large Hex, why not a small Hex.

Here to learn so interested in your opinion.
Kafoozalem - on 04 Jun 2014
In reply to The Ex-Engineer:

You won't find me belayed to one piece since I don't take a strain guage to the crag to measure the required 2-3kn or is it 6kn (Jim Titt). Frankly I am too aware that in the real world SHIT HAPPENS - and often times it isn't clear how. At the belay on Behemoth at the weekend I noticed one of my bomber nuts had worked it's way out of the crack - how, I don't know. Thank goodness I was superstitious enough to have a multipiece belay.
Oujmik - on 04 Jun 2014
In reply to CurlyStevo:

I use 7mm in a closed loop for my cordalettes. I use them for multipitch anchors when not swinging leads and if the pieces are too far apart for equalisation with a sling or two. Otherwise, I always prefer to equalise with the rope.

A couple of much more experienced climbers have mentioned to me that they'd like to see a manufacturer produce a dynamic cord/sling for equalization, but apparently to meet standards for breaking strain it would have to be made from full weight dynamic rope so would be prohibitively heavy - you could always make one of these yourself if you feel inclined. I was toying with the idea of making one from a super skinny twin rope, but not worth the hassle or expense right now.

I don't know much about abseil tat, but from physics point of view remember than if the tat is tied quite tightly around the spike/block/anchor then the angle where it joins your rope will be large which will increase the force along the length of the tat substantially beyond that which you exert on the rope.
jimtitt - on 04 Jun 2014
In reply to CurlyStevo:

This is so, there are plenty of belayer/belay device/ rope combinations out there in common use where the forces are far more than 2 or 3kN. Not building belays to hold a FF2 is ridiculous, in a multi-pitch scenario any lower fall factor and by definition we can dispense with the belay altogether anyway so once the leader is under way we could dismantle it. Simul-climbing anyone?
The Ex-Engineer - on 04 Jun 2014
In reply to CurlyStevo:
> Your view is at odds with that of Libby Peters
> http://www.ukclimbing.com/articles/page.php?id=2592
> "some Gogarth belays require 5 or 6 pieces"

They are generally hanging belays. The statement is not necessarily at odds with my previous post as I did specifically say they were an exception.

On a good VDiff type stance, if you have doubts about a belay anchor it is trivially easy to inspect and adjust it. Also you will generally be able load it or even bounce test it fairly safely and see what happens. On a hanging stance gear is often harder to arrange and inspect, plus in the worst case it will be impossible to load or test it in any meaningful way. Add in the fact that the anchors will be continuously loaded with the climbers' bodyweight then I can see no reasons not to employ a far more paranoid approach.

As Jim points out the climbers weight of perhaps 2kN explains the difference between my 2-3kN figure and the 6kN he mentions.

> Also I reckon a modern plate on half ropes (say an ATC XP guide on 8.5 mm genesis) would be able to exert more than 3 kn on each rope (bd say it has 3 times the breaking force) so a factor two fall could easily reach max forces on the belay of around 6kn.

I'd suggest you read the info on belay devices on Jim's website "Belay Device Theory, Testing and Practice". It is part 7 (bottom of the very large page) on http://www.bolt-products.com/Glue-inBoltDesign.htm

He has actually test result for an ATC XP. With a really firm grip (400N) on a single rope the highest force he obtained was 2.8kN.

Doubles ropes will not double the forces and as the same grip force is just split between the two ropes. In fact, going from Jim test results for varying rope diameters, with 8.5mm ropes the force is more likely around 1.2kN (4x power ratio at an average 300N grip strength) and certainly no more thn 2kN (5x power ratio at 400N grip strength).
The Ex-Engineer - on 04 Jun 2014
In reply to SCrossley:
> now this I find interesting, why a large Hex and not a bomber No7 in a deep placement in Solid Rock, why specify a Large Hex, why not a small Hex.

Large placements are much easier to visually inspect and are in generally in contact with more rock.

A nut can be pushed, twisted or lifted via the wire, it is far harder to push, twist or lift a hex via the rope or tape.

Scrambling or mountaineering I'd have no problems using your hypothetical "bomber No7 in a deep placement in Solid Rock" but with normal rock climbing, the lack of any massive time pressure and balance of risk means I'd generally go for 2 wires.

I don't have any issue with backing up gear if there is any doubt. It is just the logic of then backing up the back up that I question.
The Ex-Engineer - on 04 Jun 2014
In reply to Kafoozalem:
> I don't take a strain guage to the crag to measure the required 2-3kn or is it 6kn.

You obviously don't aid climb otherwise you'd know that testing gear to several kN is no problem. Aid climbers do it with pretty much every single piece they place - http://www.andy-kirkpatrick.com/articles/view/testing
CurlyStevo - on 04 Jun 2014
In reply to The Ex-Engineer:
> They are generally hanging belays. The statement is not necessarily at odds with my previous post as I did specifically say they were an exception.

Libby does not make that distinction, and what she says is pretty much in line with what I said. I quote from Libby's article:

"Just occasionally you may be happy to use only one totally bombproof anchor"

"Most of the time you'll want at least two bombproof anchors in your belay. If either of these are anything less than perfect add a third and so on"

This is in contraindication with what you said - "Suggesting otherwise (even implicitly) by equating more gear with a BETTER belay is not something I would consider particularly sensible"

> On a good VDiff type stance, if you have doubts about a belay anchor it is trivially easy to inspect and adjust it. Also you will generally be able load it or even bounce test it fairly safely and see what happens.

Your original posts were not limited only to large VDiff ledges, in any case do you really go about bounce testing belay anchors?

> As Jim points out the climbers weight of perhaps 2kN explains the difference between my 2-3kN figure and the 6kN he mentions.

Not really The weight of the fallen climber is accounted for already in the slipping of the belay plate and most climbers weigh around 80kg or less so the belaying climbing is unlikely to add much more than 1kn to the system if the attachment to the anchors is fairly tight. So using your model we are still looking at the belay only needing to hold 3-4 kn.

I wonder what forces would be exerted on the belay if climbers are 100 metres up, the leader factor 2 falls, the belayer can't hold the fall and let's go of the rope and the leader than falls with the rope free slipping through the device until the rope has completely slipped through the device. Or indeed factor 2 falls with all the rope paid out (which is possibly however unlikely - perhaps some gear rips but isn't good enough to slow the fall much). In this case the force on the belay could be much higher than 2-3 kn!

> I'd suggest you read the info on belay devices on Jim's website "Belay Device Theory, Testing and Practice". It is part 7 (bottom of the very large page) on http://www.bolt-products.com/Glue-inBoltDesign.htm

Yeah I have read that before.

> He has actually test result for an ATC XP. With a really firm grip (400N) on a single rope the highest force he obtained was 2.8kN.

Sure but I did mention the ATC XP guide which I have found (from owning both devices and abseiling) has quite alot more friction on narrow ropes than the normal ATC XP and has different shape cleats.

> Doubles ropes will not double the forces and as the same grip force is just split between the two ropes. In fact, going from Jim test results for varying rope diameters, with 8.5mm ropes the force is more likely around 1.2kN (4x power ratio at an average 300N grip strength) and certainly no more thn 2kN (5x power ratio at 400N grip strength).

OK if belaying on a single 8.5mm rope you can see from his test results that the holding force before the ropes slips through the device on a normal ATC XP in high friction mode is around 70% of a 10mm. So actually we'd be looking at roughly 1.96 kn for 400n hand force.

I also question your assumption that this figure would be the same for two half ropes as the hand force is split. I can see your logic but the ropes are both going over a breaking cleat so I suspect the actual result is more complex than that, certainly you would expect the ropes to slip less through the device when holding heavy falls than using a single strand - but I do take your point that my original assumption was incorrect.
Post edited at 11:25
CurlyStevo - on 04 Jun 2014
In reply to jimtitt:

It's interesting that your test results do not seem to agree with the BD ones or are they testing different things?

BD claim that ATC XP has "3 times greater hold and stopping power" however your test results don't seem to show anything like that.
CurlyStevo - on 04 Jun 2014
In reply to The Ex-Engineer:
> Even if a factor two fall happens, worrying about the strength of the belay may be irrelevant unless the belayer is wearing gloves. If they aren't, the leader will very likely be dropped most of the rope length before the belay is even loaded.


Posters in this thread seem to have had a different experience, it seems post waist belaying (ie using a belay device) that most factor 2 (ish) falls can be held and not always with burns to the hands.

http://www.ukclimbing.com/forums/t.php?t=413032
Post edited at 14:03
jimtitt - on 04 Jun 2014
In reply to CurlyStevo:

> It's interesting that your test results do not seem to agree with the BD ones or are they testing different things?

> BD claim that ATC XP has "3 times greater hold and stopping power" however your test results don't seem to show anything like that.

Thatīs called advertising, for the model without the holes they claimed either 2x or 3x depending on where you looked. Their own tests and everybody elses show about 20% more. Nobody has ever built belay plate that powerful.
CurlyStevo - on 04 Jun 2014
In reply to jimtitt:

Pretty weird isn't it!

I think if you tested the ATC XP Guide you'd find that more grabby than the normal ATC XP. The normal one I can abseil in hi friction mode with a prussic on 8.5 mm genesis no problem, but the guide I need to turn it the low friction way around. Probably only a bit more though looking at your chart :)
jimtitt - on 04 Jun 2014
In reply to CurlyStevo:

Some climbers weigh more than 80kg, Iīm one of them! Then there is the gear, rucksack, bivvy gear etc etc. The UIAA donīt just look at anorexic sport climbers but a wider selection of the climbing popululation and the weight used is a tad over 100kg. (which is converted for a hard body in a harness to 80kg for impact testing).

Achieving 400N hand force is for the very few, I use a weight instead! An acceptable value is between 16N and 250N and 300N is exceptionally good.

With 2 x 9mm ropes through a Reversoģ which is very marginally weaker than an ATC XP Guide I can hold 2,3kN.
The figures for braking power and the relevance to slip and potential rope burns arenīt the same as the peak force one can achieve. Very briefly one can hold considerably more before slip occurs and so the maximum force on the anchor will be higher than the steady state force one can hold for the time required to stop a fall. Possibly 30-40% looking at some of the drop tests but itīs hard to be accurate.
BUT the ATC XP and itīs relatives are not the pinnacle of braking power, merely that of conventional plates and particularly nowadays there are loads of other devices out there in common use with far higher braking forces (not even considering the venerable HMS which easily gets 50% more).
Things like the Smart, ClickUp, Mega Jul and so on get far higher values (so long as the climber orientates his hand correctly to make them work altogether in a FF2) and there are plenty more exotic ones like the Nine, TRE Sirius, Antz, B52, BRD etc. With a Smart Alpine I can pull 3,6kN easily enough on 2 ropes and the ClickUp is considerably more powerful still, Iīd hazard a guess that considerably over 5kN is easily achievable with a single 10.2.

AND! Building belays on the basis of test results for belay devices requires that the device functions as intended. Others with more experience would contend that until either the persons saying how strong the belay should be or the device manufacturer can give a cast-iron guarantee that the rope will not twist, tangle, get caught on a bush, be stood on or mysteriously tie a slipped hitch then weīll carry on making our belays a bit stronger than 2 or 3kN, just in case it doesnīt work like in the books:-).

The Ex-Engineer - on 04 Jun 2014
In reply to CurlyStevo: Many points are just re-hashing previous comments, but I will address one:

> in any case do you really go about bounce testing belay anchors?

Yes, in some situations, I do.

I'll do it occasionally when instructing. It is a good way to provide an objective test of an anchor, especially if there is a difference of opinion about its strength. It can provide a very effective demonstration in situations where the 'solid' anchor a student thinks they have just placed is actually nothing of the sort.

On the rare occasions where I need to use them as belay anchors, assuming its feasible, I'll try to do some sort of test on any micro-wires (and to a lesser extent, any micro-cams) to check they are seated securely and they aren't going to rip as soon as they are loaded.

In both situations I'd generally use a quickdraw or two clipped between the gear and my belay loop.
jimtitt - on 05 Jun 2014
In reply to The Ex-Engineer:

Itīs suprising how little force you can achieve bounce testing though. Metolius say about 2kN and a guy in the US and myself tested this as wellfor aid climbing. 2 to 2.5kN is realistically about it as it starts getting extremely painful if your doing a waist drop and a leg bounce is somewhat restricted by the strength of your leg. The limitation really is itīs extemely hard to actually jump upwards standing in a sling and coming back down gets painful.
In a normal climbing situation one could always climb above the piece and drop off but that sounds like a way to die somehow!

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