minimum Kn for climbing

[Ray]

But that is for rock climbing, where all kit has to be ce marked but there are no legal requirements for climbers to abide by any rules concerning strength ratings or indeed condition of kit. 22kn is fine.

[skyhuck]

Also a rock climber is using a "fall arrest system" we should be using "work positioning System" BIG difference.

[RPA]

Also a rock climber is using a "fall arrest system" we should be using "work positioning System" BIG difference.

 

I agree that there is a big difference BUT it does bring up a very good point that has not been looked at during the thread.

 

People are understandably concerned by weight but safety wise we MUST look at things in force kN not kg (weight). Every climber will exert a force on his equipment greater than that of his static weight.

 

Calculations of force can be calculated (ie rigging etc) but its far easier just to get a krab => 22kN

[Rupe]

The title of the thread includes the letters " kn "

 

How has that been overlooked! Its what the thread is about!

[RPA]

 

The reasoning works if you start with the climber, and say

 

1 climber = 100 kgs +10 for clothing/kit/saw 110 kgs.

 

Then x2 for rescue purposes =220kg

 

then factor 10 for safety 220x10 = 2200kgs =22Kn.

 

That would be good logic!

 

Weight calcs or force calcs?

 

Just my view, its a forum!

[RPA]

p.s.

 

A Knot is a nautical mile per hour (kn)

 

A Kilonewton is an SI unit of force (kN)

 

http://en.wikipedia.org/wiki/KN

[Rod]

shabs was giving his workings out to support his reasoning why it would in his oppinion be 22kN min

 

as rupe sais the whole point of the thread was to discover the min requirement kN for karabiners :001_smile:and we have:001_smile:

[Chris Cowell]

Ray

 

I've been trying to work out how it is possible to generate 12kN in a rock climbing scenario (Klettersteig excluded). What with the knots, dynamic rope, potentially a number of hardware placements and a mobile belayer, I can't picture how that force is achieveable. I asked around a bit, and 4-7kN was the consensus. Could you enlighten me please? 12kN would hurt alot......

 

Chris

[scotspine1]

Ray

 

I've been trying to work out how it is possible to generate 12kN in a rock climbing scenario (Klettersteig excluded). What with the knots, dynamic rope, potentially a number of hardware placements and a mobile belayer, I can't picture how that force is achieveable. I asked around a bit, and 4-7kN was the consensus. Could you enlighten me please? 12kN would hurt alot......

 

Chris

 

Not directly related to what your talking about Chris, but interesting nevertheless -

 

[ame=

]

[/ame]

 

Some people might say this would never happen in a treeclimbing scenario, but I've seen guys ascend more than 12 ft using a VT before holding and pulling the slack through. At 13 Kn of force, its fair to say if this were a real person they'd have suffered horrific injuries, at the very least their spine would've snapped in two.

[Chris Cowell]

We seem to be on the verge of running three discussions at the same time. The thread started with a question about kN rating for tree climbing gear (Work Positioning), then rock climbing was added and now we have fall arrest! Does anyone want to discuss work restraint also?!

 

Tim. I've seen many tree climbers accumulate far too much slack, sometimes they are on VT's but other times a Blakes or Prusik. In my early VT days I didn't always manage slack in the way I should have. Undertsanding the consequences, acquiring skills and exercising self discipline are key here. Bad practice is difficult to legislate against....

 

The test shown in the video is a dynamic strength test for EN361 i.e. a PPE standard covering full body harnesses that may be used for fall arrest. On a work site, energy absorbers (e.g. certified to EN355) should be incorporated into fall arrest systems to reduce the forces experienced by a climber in the event of a fall. Part of the definition of fall arrest is that there must be a clear zone to fall into. Fall arrest is not a system we can adopt in trees because of the proximity of objects that could be contacted by a climber during a fall e.g. branches, stubs, the ground. Therefore, it is up to each climber to manage their system to ensure excessive slack is not created i.e. take resonsibility.

 

Anyone who saw the ascent demo at last years Trade Fair will know that this topic (work positioning/fall arrest/clear zones) was touched upon.

 

For info, there will be an updated version of the Hitch Climbers Guide at treemagineers.com on or around 20th April. There is a section entitled 'Managing Slack' which shows a few techniques to help to manage out slack when work positioning in trees. In that way, there should be no reason to experience anything like the peak force created in the video drop test.

 

 

Ray. I'm still keen to understand how 12kN is possible in rock climbing.

 

Chris