/ Heavy climber and trad gear
I trad climb weekly at around VS/HVS, cragging and multipitch.
I am quite a tall fella (6'4) and weighs a bit more than 100 kg. With gear, backpack clothing and you would easily end up with a mass of around 115kg.
I was trying to understand what kind of force a falling mass would generate on a piece of gear in a fall and came across this :
According to their tests, a falling climber weighing 114kg on a typical dynamic rope, with a factor 0.9, would generate 8.2KN on the falling climber, multiply by 2/3 to find the approfimate force on the runner, and you find 13.7 KN !
Most small cams and small nuts fail at 7kn or less, medium ones at 12KN, and big ones at 14KN.
This is right at the limit of almost any piece of gear I have. judging by their tests, the only piece of gear able to hold a guy like me in a fall factor above anything more than 1 would be a sling around a massive flake.
Until now every fall I took the gear held, but looking at these tests and the scientific evidence I am wondering whether my confidence is simply misplaced, and whether I am simply too heavy to lead hard multipitch routes where a fall facor above 1 is a likely possibility without putting my partner at risk.
8.2*(2/3) is only 5.47
Worry ye not.
Mind you my sister is good at belaying (only 8 stone) this might help
> 8.2*(2/3) is only 5.47
> Worry ye not.
"Without going into all the details, the widely accepted rule of thumb is that the top piece of gear in your system will experience 2/3 MORE force than that felt by the falling climber...."
i.e. 8.2 + 5.5 = 13.7kN
It is also worth noting that the ratings on gear are a lower limit, there's a very good chance they'll hold more than that, though by exactly how much is a bit of a lottery.
As others have said, a fall factor of 1 is pretty unusual, let alone anything above it. A fall factor above 1 should very rarely be a likely possibility. I'm sure you're already taking precautions to try and avoid high-factor falls, the lesson is probably to be extra-careful about avoiding those falls rather than to stop climbing multi-pitch.
> "Without going into all the details, the widely accepted rule of thumb is that the top piece of gear in your system will experience 2/3 MORE force than that felt by the falling climber...."
> i.e. 8.2 + 5.5 = 13.7kN
I live and learn.
I was just replying to this
would generate 8.2KN ... multiply by 2/3 to find the approfimate force on the runner... 13.7 KN !
'm reading the pdf from the OP now (couldn't on my phone)
Interesting as I'm 86 kg. I shall avoid falling off.
I have seen a heavy Climber break a piece only once and it was a very small wire and first piece on the route so not much rope to give. He did land on his ass, which could have meannt Back injuries But was OK luckily. He was very large, probably obese however. I would think 120-30 kg maybe.
Usually even a heavy person makes a lot less force than this
Generally the limiting factor is the belay device and your unlikely to see more than 6kN on the top piece unless you do something very peculiar, most devices are only capable of giving considerably less than 3kN braking force.
Interesting test results but they don't reflect reality. They're using a rigid belay point, rigid mass and a very severe fall, none of these are the norm on a real route. In reality belayers get flung around, belay plates slip, bodies crumple absorbing energy. The closest you'll get to those conditions is using something like a GriGri and a well aligned and solid ground/upward-pull anchor which is not something I've ever seen in the real world.
I'd add the 'None of my previous falls snapped anything' points to your data set, they're as valid as the data in the paper you found if not more so.
I'm "only" around 15 stone now, but was leading when 18 stone plus. I've taken a couple of falls, both onto no 3 nuts, at that weight, and there wasn't a problem. One of them was a bit difficult to extract afterwards! The only time I've been injured was taking a ground fall *before* I'd got any gear in! Broke my elbow and learned that even on "easy" routes it's a good idea to get a bit of gear in soon after you've left the ground :-) .
I guess a light climber would probably get away with a lot more than a heavy climber would. For big fellas like me I guess it is sensible not to go for bold routes with high fall factor potential and marginal gear unless they are at a grade where super confident. A disatrous fall factor 1.5 would be hard but ok for someone 70kg, for someone like me it would be probably gear destroying and bone breaking.
One interesting thing would be to see how much force is dissipated by heat by slippage in the belay device. And of course the belayer would absorb quite a lot of the force as well by being moved into a different position, but on a multipitch climb, most of the time my belayer is anchored fairly thightly to a multidirectional belay. Maybe that is something to change and allow SOME slack in the system so that the belayer can move quite a bit without the risk for him/her to be pulled out of his stance.
Once at the climbing wall a foothold broke under my weight and I went flying instantly just after the first clip, whilst clipping the second clip (had quite a bit of slack in my hand). My belayer ended up acting as a bouldering mat ;-)
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