Beal Cord break strength

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Rockray143
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Beal Cord break strength

Post by Rockray143 » Thu Feb 21, 2019 7:58 pm

I bought some Beal cords 6mm. According to the spec sheet it has a breaking strength of 810daN(kg) not sure how this translates to KN any assistance would be appreciated thanks

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robertbreyer
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Re: Beal Cord break strength

Post by robertbreyer » Thu Feb 21, 2019 8:24 pm

da = deka = 10.
1 daN = 10 Newton.
So 810 daN = 8100 N
F=m*a (Force = mass * acceleration)
m=F/a
in this case, a = g (gravity)
g = 9.8m/s^2
m = 8100/9.8 = 826 kg.

So i think it will hold your bodyweight.

in fact, if you are an average climbing adult of say 70 to 75 kg odd, then you could bring along a whole soccer team to hang off that 6mm chord.

- robert

Rockray143
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Re: Beal Cord break strength

Post by Rockray143 » Thu Feb 21, 2019 8:35 pm

Thanks, so this would work for building quad anchors on belay stances

legendarry
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Re: Beal Cord break strength

Post by legendarry » Thu Feb 21, 2019 9:33 pm

Yeah. It’s fine for a quad anchor stance.

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Nic Le Maitre
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Re: Beal Cord break strength

Post by Nic Le Maitre » Fri Feb 22, 2019 10:51 am

It's fine, but just use the rope, you're carrying it anyway. Those "self equalizing" quad anchor things that all the US climbers love so much, well they really don't actually equalise.
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Old Smelly
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Re: Beal Cord break strength

Post by Old Smelly » Fri Feb 22, 2019 10:59 am

Just to note that this is not so easily explained away when dealing with shock loads - as an 81 Kg person can generate that 810 KgF quite easily if falling.

So though I am not disputing Roberts assessment one needs to always look at an application of cord as in many situations his would be insufficient on its own. So you could lift the whole soccer team statically but if you drop one of them hard onto that cord it would snap (most likely) - particularly if it was a member of a Rugby team and he actually weighed 100 Kg! Remember a cross loaded carabiner will snap at about the same force (±700 KgF)

In the case of a quad there are multiple strands and they equalise the load between the strands, however, there are knots and they weaken the overall strength of the system. The knot apparently can weaken the joins by as much as 40%. What that means is if your rating was 810KgF on each strand then the anchor should take 3 or 4 times this load (about 2,4 tons) but reduced by 40% (about 1,4 tons as a very rough approximation)

So does a stance need to take shock loads? Not for the seconds normally. And when you belay your climber off the stance you most likely will belay off your body and have the equalised anchor attached to you (able to take a directional load) - where you act as the shock absorber (sack of potatoes). So when would the stance see a massive shock load? When the climber leads away from the stance and you are not belaying off your body but directly off the anchor. If they then fall without placing gear then your anchor will see a massive shock load from a factor 2 fall. This is a worst case scenario but in that case the leader may be able to generate the 700KgF forces that could snap a strand if it was taking all the forces.Fortunately in a quad or equaliser scenario that won't happen - but it does show why one should build decent anchors (and belay off your harness for the lead climber).

It does raise the question as to whether a sling rated at 2,5KN (2,5 tons) would not be better used as your equaliser. Current thinking is that cord shock absorbs better and so is better suited as an equaliser - however, when you consider that the sling starts off 3X stronger and also experiences the same strength reductions (approximately) then maybe it is not such an obvious answer - maybe cord is only better when the rating is close to the strength of a sling.

Long and short 6mm at 810 Kg rating only just does it with a safety factor of 1,75 (using the 1458 from the anchor calc.). If you used 7mm cord the strength of the cord goes up to 1,17 Tons, which is 1,4 times stronger and tips the Factor of Safety in the right direction (FOS of 2,6 in comparison to the 1,75). Personally that is where I would place my bets for a choice of cord for a quad or Equallete - the strength of the anchor is considerably more for a relatively minor weight increase.
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Old Smelly
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Re: Beal Cord break strength

Post by Old Smelly » Fri Feb 22, 2019 11:04 am

As to Nic's comment - if you are leaving the anchor in place and leading off again then using the rope is impractical and a cumbersome solution.

Using an Equalising Anchor system is generally more simple and leaves one with a lot of flexibility in terms of self rescue, second rescue and multiple other scenario's> Learn all methods and choose what to use and when. Do not rely solely on one method - like just using the rope- as this is not always the best solution.

If you are often the leader of multiple pitches with several seconds then Equaliser anchors are optimal in most situations.
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shorti
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Re: Beal Cord break strength

Post by shorti » Fri Feb 22, 2019 11:50 am

Quad, as in 4 pieces? Why?

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Nic Le Maitre
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Re: Beal Cord break strength

Post by Nic Le Maitre » Fri Feb 22, 2019 12:49 pm

shorti wrote:
Fri Feb 22, 2019 11:50 am
Quad, as in 4 pieces? Why?
https://www.youtube.com/watch?v=80Oqs5i5CfE
Happy climbing
Nic

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Nic Le Maitre
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Re: Beal Cord break strength

Post by Nic Le Maitre » Fri Feb 22, 2019 1:03 pm

Old Smelly wrote:
Fri Feb 22, 2019 11:04 am
As to Nic's comment - if you are leaving the anchor in place and leading off again then using the rope is impractical and a cumbersome solution.

Using an Equalising Anchor system is generally more simple and leaves one with a lot of flexibility in terms of self rescue, second rescue and multiple other scenario's> Learn all methods and choose what to use and when. Do not rely solely on one method - like just using the rope- as this is not always the best solution.

If you are often the leader of multiple pitches with several seconds then Equaliser anchors are optimal in most situations.
The quad thing means that you are restricted in how you can build your anchor, how far apart you can have your points, how far from the wall you can be etc etc. It often prevents you from being able to see your climber, or positions you directly under them on straight routes, all of which have serious safety drawbacks.

Sure if you are leading every pitch then changing over is a bit of a hack, but you just swap ends of the rope and continue. You also need two of these quad things so you can have one at each anchor.

There is no perfect solution but in my experience, just using the rope does most everything well.
Happy climbing
Nic

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Nic Le Maitre
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Re: Beal Cord break strength

Post by Nic Le Maitre » Fri Feb 22, 2019 1:08 pm

And here is some actual data on forces generated in the anchor by falls:

https://www.petzl.com/INT/en/Sport/Forc ... -real-fall
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Old Smelly
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Re: Beal Cord break strength

Post by Old Smelly » Fri Feb 22, 2019 4:27 pm

One of the basics that beginners are taught when first starting multi pitch climbs is that you stay tied in until you are safely back on Terra Firma. It is a basic safety rule.

Advocating untying on stances is downright diabolical and will require that seconds have tethers anyway and to be safe these would need to be redundant (i.e. more then two). So please do what you like.............. but don't argue that it is easier (or as safe) as using a dedicated anchor system.

That is the reason most professional guides use anchor systems that they can leave their clients attached to whilst they lead the next pitch. Yes I think the followers need to have tethers anyway and yes I agree there are many instances where using the rope to create the anchor is the best solution. Just glibly planning to always untie from the ends because you think that is the best method - that is also questionable. Your choice BUT not what should be recommended as standard practice. It may occasionally happen but planning it in...

And yes - please look at the Petzl calcs but note that none of them involved a Factor 2 fall. If they had, then the generated Forces on the anchor would be similar to those experienced by the climber (close to the 5KN mark).

My general calc. was to show how much better the 7mm cord is than the 6mm, not to be taken as much more then that.

Using an Equaliser method requires practice but is functionally better then the cordelette method - which is the general method used when using the rope, unless you belay off your harness and use the rope to attach to the anchor. If you READ the Falcon book "Climbing Anchors" it explains it all very well.

Quads are limited in their application, Equalisers less so and the cordellette method more so. I still suggest that you need to learn about all of them and apply each when applicable.
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Nic Le Maitre
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Re: Beal Cord break strength

Post by Nic Le Maitre » Mon Feb 25, 2019 8:49 am

Old Smelly wrote:
Fri Feb 22, 2019 4:27 pm
One of the basics that beginners are taught when first starting multi pitch climbs is that you stay tied in until you are safely back on Terra Firma. It is a basic safety rule.

Advocating untying on stances is downright diabolical and will require that seconds have tethers anyway and to be safe these would need to be redundant (i.e. more then two). So please do what you like.............. but don't argue that it is easier (or as safe) as using a dedicated anchor system.
And I'd argue that the ability to untie and swap ends safely is a vital skill that everyone climbing multipitch routes should possess. I often climb as a group of 3 and switch leads. With two ropes it's possible to switch leaders without anyone ever being off the anchor/belay.

Old Smelly wrote:
Fri Feb 22, 2019 4:27 pm
That is the reason most professional guides use anchor systems that they can leave their clients attached to whilst they lead the next pitch. Yes I think the followers need to have tethers anyway and yes I agree there are many instances where using the rope to create the anchor is the best solution. Just glibly planning to always untie from the ends because you think that is the best method - that is also questionable. Your choice BUT not what should be recommended as standard practice. It may occasionally happen but planning it in...
Ah but we're not talking about professional guides leading every pitch with clients of questionable competency are we? They have to plan as if their client can maybe safely belay them. You tailor your methods to the partner you have.
Old Smelly wrote:
Fri Feb 22, 2019 4:27 pm
And yes - please look at the Petzl calcs but note that none of them involved a Factor 2 fall. If they had, then the generated Forces on the anchor would be similar to those experienced by the climber (close to the 5KN mark).
FYI, the EU norm for a survivable fall is 6kN, so I think that your calculations may be a little on the high side. There is an incredible amount of dynamic absorbance built into climbing systems. With a 80kg rigid steel mass you might get there, but with squishy soft humans it's unlikely
Old Smelly wrote:
Fri Feb 22, 2019 4:27 pm
My general calc. was to show how much better the 7mm cord is than the 6mm, not to be taken as much more then that.
But by extension, then 8mm is better than 7mm, and 9mm is better than 8mm and and and... The question was, is it good enough? And the answer to that is yes, the 6mm cord is good enough.
Old Smelly wrote:
Fri Feb 22, 2019 4:27 pm
Quads are limited in their application, Equalisers less so and the cordellette method more so. I still suggest that you need to learn about all of them and apply each when applicable.
Good point
Happy climbing
Nic

Old Smelly
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Re: Beal Cord break strength

Post by Old Smelly » Mon Feb 25, 2019 9:30 am

Thank You Nic - such high praise- a final good point!

However others who may read this forum may think you are just be argumentative after your previous simplistic instructions, so I will try to create some context;

Yes tying in and out is a useful skill - but that does not detract from the risk one adds to doing this on a cliff face. YES it is sometimes necessary - however one should not advocate it as the norm.

The next point is that my observation that guides do use equalisers and quads means it is a very good practice - particularly if you are an experienced leader leaving novices behind - something that may be useful for readers of this forum - as opposed to recommending untying at every stance.

The other point that needs to be made is one that you have agreed upon and that is that one needs a good understanding of all of these ideas to choose which is best - not to only know one method and try and make it fit all situations (such as Use the rope)- hence my recommending reading the anchor book (or others) to formulate your own solution.

I feel 7mm diameter cord pushing the strength above 1 ton is meaningful whilst not adding that much weight. Sure you can use a piece of climbing rope or 6mm- at least an informed choice is better then just taking someone else's word for it - and I am not implying that the soccer team claim is wrong -just not the only factor. Arguing thicker diameters will be stronger and stronger is obvious and a bit disingenuous -unsurprisingly.

However to get back to the original question - yes 6mm is strong enough and I believe 7mm preferable as I attempted to explain.
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shorti
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Re: Beal Cord break strength

Post by shorti » Mon Feb 25, 2019 1:07 pm

Nic Le Maitre wrote:
Fri Feb 22, 2019 12:49 pm
shorti wrote:
Fri Feb 22, 2019 11:50 am
Quad, as in 4 pieces? Why?
https://www.youtube.com/watch?v=80Oqs5i5CfE
Oh, ok, thanks Nic. I was expecting something like a four anchor cordelette or something silly like that.

Old Smelly
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Re: Beal Cord break strength

Post by Old Smelly » Tue Feb 26, 2019 12:39 pm

On the topic...

https://rockandice.com/climbing-news/cl ... -the-quad/

and

https://rockandice.com/how-to-climb/cli ... reloaded=1

and finally on the topic of 4 point anchors... (which are sometimes necessary...or something silly like that)

https://www.climbing.com/skills/learn-t ... or-rubric/
Really, its not that bad...I think it's my shoes...

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