Chockstone Forum

      Sponsored By
      ROCK
   HARDWARE

Chockstone Photography

Australian Landscape Prints

Chockstone Forum - General Discussion

General Climbing Discussion

Author

Exploding Rope

pensionerpower

6-Sep-2005
5:20:42 PM

Hm, sorry Obsessedclimber, not trying to steal your thunder. Your post did not show up here, until after I'd sent mine :-)


nmonteith

6-Sep-2005
5:23:19 PM

On 6/09/2005 deadpoint wrote:
>The rope jammed behind the flake. ie Pete was 6m above the flake, ended
>up 6m below flake, 12m total fall - fall factor two. There was no force
>whatsoever on the belayers end of the rope.

That is a freaky accident! Your original post was not very clear about what exactly happened. It certainly
sounds like factor 2 to me now that I know the details!


Super Saiyan

6-Sep-2005
5:26:03 PM

isnt that what i just said? lol

your body will break before your gear. from what i can remember, you body can can sustain 12kN for a very brief time before internal injury, ribs breaking, spine gone etc etc most equip is rated a minimum of 15ish kN (a generalisation i know)


Super Saiyan

6-Sep-2005
5:33:55 PM

RE: protection systems

EALs (Energy Absorbing Lanyards) are by far the best thing to minimise the damage and effect of static falls. For those not in the know, they consist of two slings of different length (so u cant hang urself if u fall off and get ur head caught) with lobster claws at each end. these are attached with a d-ring to a shock absorber, which is tied with a larks foot or mallion to ur harness. It means you dont have to unclip entirely to pass attachment points etc. and any falls are reduced under fall factor 2 (on your body) by the energy absorber tearing open.

obviously, these stil suck on the via ferrata described above, and climbing, but are rad for high ropes and industrial puposes

patto

6-Sep-2005
6:35:21 PM

On 6/09/2005 obsessedclimber wrote:
>isnt that what i just said? lol
>
>your body will break before your gear. from what i can remember, you body
>can can sustain 12kN for a very brief time before internal injury, ribs
>breaking, spine gone etc etc most equip is rated a minimum of 15ish kN
>(a generalisation i know)

It all depends on the point of contact of the force. For example people can sustain decelerations of around 40G for very brief periods of time (see Colonel Stapp). This amounts to a force of over 30kN (assuming 75kg in weight).

Rough back of the paper caculations indicate that a 5m factor 5 fall would result in 16G (over 0.05s) and around 11.2KN. Your body could easily survive this if it was in a full chest harness. However if you get whipped around in a regular harness broken spine could easily happen.

There is a big difference between a 5m factor 5 fall and a 20m factor 5 fall. The time which the force is exerted for is important. Also for short falls other shock absorbtion comes into play like harness and bum compression which makes a big difference.


Phil S

6-Sep-2005
9:09:52 PM

In the late eighties I was lowering a friend off an overhung route when the sheath ruptured, about an equal distance from the climber and the anchor. He was also quite startled. It was a borrowed rope too, kind of hard to explain:
- "Sorry Dave, your rope broke while we were climbing..."
- "!?!..."
- "No seriously dude, we didn't do anything. It just broke. All by itself!"

It would be interesting to test your exploding rope to failure, Neil. Certainly, its elasticity will have been effected but I would expect the rope to have retained 80 - 90% of its strength under a static load since only a small fraction of its fibres are in the (now defunct) sheath.


aikibujin

6-Sep-2005
10:12:05 PM

On 6/09/2005 pensionerpower wrote:
>Folks, I am just an indoor junkie - I dislike outside (too many flies;
>no carpets!), but I do know my fall factors!

Well here's a question for you: in rock climbing (not in Via Ferrata) it is theoretically possible to generate a slightly greater than FF2 fall. Can you describe the scenario?


Super Saiyan

6-Sep-2005
10:18:46 PM

what about if u are leading the second (or 3rd, or 4th) pitch of a multipitch, belayer on hangin belay, you fall off, no protection placed, pulling the belay off as you pass.... fall factor oh f---?


Eduardo Slabofvic

6-Sep-2005
10:32:37 PM

On 6/09/2005 aikibujin wrote:

>Well here's a question for you: in rock climbing (not in Via Ferrata)
>it is theoretically possible to generate a slightly greater than FF2 fall.
>Can you describe the scenario?

The answer is simple. Climb with a belayer from Queensland.

rightarmbad

6-Sep-2005
11:07:27 PM

If you fall far enough and the belayer has enough time to take in a couple of meters, then you will exeed a fall factor 2.


Rich

6-Sep-2005
11:53:49 PM

what if... you fall off say 30m up 3rd pitch on a multi-pitch, pull all your gear, blow the belay and you and the belayer hurtle towards certain death when your rope wraps around the top belayer on a party of 3 below you (with 2 belayers of course), blowing that belay too and then you are only held on by 2 cams, one of which blows and then the other starts sliding.... what then huh?
;-)


cheesehead

7-Sep-2005
7:55:37 AM

Well, If those cams don't hold, then I'd say you've fallen from your vertical limit


rodw

7-Sep-2005
8:01:22 AM

Thats when you take your knife and cut is to your climbing partner hurtles to a grusome end....grab your mobile phone and ring BBC for the film rights and get an agent for ready for the book signing tour... so who coming climbing with me???

On 6/09/2005 Rich wrote:
>what if... you fall off say 30m up 3rd pitch on a multi-pitch, pull all
>your gear, blow the belay and you and the belayer hurtle towards certain
>death when your rope wraps around the top belayer on a party of 3 below
>you (with 2 belayers of course), blowing that belay too and then you are
>only held on by 2 cams, one of which blows and then the other starts sliding....
>what then huh?
>;-)

Aiko

7-Sep-2005
9:54:53 AM

>>can can sustain 12kN for a very brief time before internal injury, ribs
>>breaking, spine gone etc etc most equip is rated a minimum of 15ish kN

I'ld much prefer to break a few ribs on a bad fall than to break the rope. Broken ribs heal, then effects of a broken rope often don't.
Don't forget to add the impact force of the belayer to the top anchor. Maybe another 70% (ish) so a 10kN fall may put 17kN on the top piece of pro.... (just guessing at numbers)

>There is a big difference between a 5m factor 5 fall and a 20m factor
>5 fall. The time which the force is exerted for is important.

I assume you're meaning FF2 (not FF5)
in any case, if it were static rope I'ld be noding my head with you, but for dynamic rope, I'm not sure I agree.
The time is important, I agree on that, but 20m of dynamic will stretch a lot longer (both distance and time) than 5m of dynamic, thereby giving the same impact force for the same fall factor, yes/no?


rhinckle

7-Sep-2005
11:31:57 AM

the leader never falls, he says, stroking his beard.

patto

7-Sep-2005
1:44:04 PM

On 7/09/2005 Aiko wrote:
>>>can can sustain 12kN for a very brief time before internal injury, ribs
>>>breaking, spine gone etc etc most equip is rated a minimum of 15ish
>kN
>
>I'ld much prefer to break a few ribs on a bad fall than to break the rope.
> Broken ribs heal, then effects of a broken rope often don't.
>Don't forget to add the impact force of the belayer to the top anchor.
> Maybe another 70% (ish) so a 10kN fall may put 17kN on the top piece of
>pro.... (just guessing at numbers)
>
>
>>There is a big difference between a 5m factor 5 fall and a 20m factor
>>5 fall. The time which the force is exerted for is important.
>
>I assume you're meaning FF2 (not FF5)
>in any case, if it were static rope I'ld be noding my head with you, but
>for dynamic rope, I'm not sure I agree.
>The time is important, I agree on that, but 20m of dynamic will stretch
>a lot longer (both distance and time) than 5m of dynamic, thereby giving
>the same impact force for the same fall factor, yes/no?
>

(I did mean FF5 as I was also talking in regard Via Ferrata ladders.)

But reguarding your point; I agree with you that the impact force would be pretty much the same for the same fall factor. And I agree with you that 20m of dynamic rope will stretch further and for a longer time. However the damage done to you body is related to the deceleration (proportional to the impact force) and the period of time over which the body experiences the deceleration. For example a person can survive 40G for a brief period (0.1s), however longer than this their body start compressing and organs start popping. However unless your wearing a chest harness then I would be guess that the survivable G forces would be alot less.

However going back to a factor 2 fall your only experience around 6-7G so the risks of injury are much lower.

BTW im talking in acceleration terms rather than impact for terms because acceleration is what matters in terms of injuries (apart from superficial bruising).

Aiko

7-Sep-2005
1:52:42 PM

Ah,
I was thinking of it from the view of momentary force on the gear rather than force x time on the body. That makes more sense.
Thanks,
R.


Mike TS

7-Sep-2005
3:01:03 PM

On 6/09/2005 pensionerpower wrote:
>
>You will fall the 1 meter that you have climbed past C, then 3 meters
>down to B, then another meter down past B - for a total of 5 meters, ON
>ONE METER OF LINE. This is a factor FIVE fall.
>

If I'm following you, if you had a 3 metre line then you'd fall 7 metres with a fall factor of 2.33 which I guess is survivable?
Also, wouldn't you reach up to clip, which means your fall is 5 metres?

pensionerpower

7-Sep-2005
3:22:20 PM

On 7/09/2005 Mike TS wrote:

>If I'm following you, if you had a 3 metre line then you'd fall 7 metres
>with a fall factor of 2.33 which I guess is survivable?
>Also, wouldn't you reach up to clip, which means your fall is 5 metres?

Yes, that would be the FF if you had a 3m line. The only reason I said you climberd past the attachment, reaching down to reclip, was to improve the example. It gives you another meter or two to fall, thereby upping the FF :-)

Aikibujin, what was the scenario you had in mind?


Paulie

7-Sep-2005
8:25:39 PM

Similar thing happened to a mate of mine on the Nth Wall at Buffalo while jumaring, the sheath ripped open and locked into the jumar which sent him sliding at a rate of knots down the rope (*eeek!*). When he stopped he looked up at the metres of kern and decided to keep jugging up it...I believe he had no choice as it was on an overhanging wall...nice.

There are 62 messages in this topic.