If a falling climber can't generate above 7 kn or 9 kn then why build climbing biners with 24 to 36 kn, cams to go up to 18 kn or other equipment that is rated 2-5 times more than what we could produce during a fall.

Why waste so much money and material building something that is way above our maximum falling forces?

Does safety factor or potential lawsuits have anything with this ?

safety and fatigue. the closer the forces are to the ultimate tensile strength of the structure, the fewer stress cycles it can take before failing due to fatigue. there is a mathematical process to predicting the fatigue life of a part. with steel, you can make that life infinite for a certain level of stress. for aluminum it is impossible for infinite fatigue life. however, you could design a biner to last for a very long time (100's of thousands of cycles) before succumbing to fatigue. not sure how much of an issue fatigue actually is for climbing gear. but the safety factor is pretty huge too. why would you fall on something that you can generate 99% of it's breaking force? don't you just feel better knowing you won't get anywhere near the breaking point?

If a falling climber can't generate above 7 kn or 9 kn then why build climbing biners with 24 to 36 kn, cams to go up to 18 kn or other equipment that is rated 2-5 times more than what we could produce during a fall.

Why waste so much money and material building something that is way above our maximum falling forces?

Does safety factor or potential lawsuits have anything with this ?

If a falling climber can't generate above 7 kn or 9 kn then why build climbing biners with 24 to 36 kn, cams to go up to 18 kn or other equipment that is rated 2-5 times more than what we could produce during a fall.

And yet we still hear of gear failures. I know I have heard of biners snapping on slacklines, harnesses failing, cams breaking, ropes snapping... etc etc I will give you that most of this was probably improper use and/or excessive wear and tear, but mfg know this shit happens and therefore build to account for a certain degree of stupidity/cheapness/laziness/misuses by the users. Also it's nice to have gear that is OBVIOUSLY way too worn to be using before it fails structurally.

Harnesses failing? Ropes "snapping?" Where else but rc.com can you get quality misinformation like this!

Jay

A falling climber can generate more than 9kn. A 200 pound climber with a 20 pound pack on (not an unusual situation) in a 1.8FF fall is going to generate more than 10kn (one of those online fall calculators says 10.6kn). With pulley effect that's 17.6kn, getting awfully close to the limit of that 18kn cam, and that's assuming a perfect placement.

And most pro is not rated to 18kn, most is in the 10-12kn range, so it's not really over engineered as much as you might think. That's one reason why you'd never want to trust your life to just 1 piece.

jt
for the record, I've had a rope "snap"once. Not from climbing, but when my neighbour's tractor was pulling a loaded cement truck through some mud.

Why waste so much money and material building something that is way above our maximum falling forces?

This is exactly why I use plastic keychain 'biners, closeline cord for rope, an old jock strap for a harness, cedar shims for pins (we don't need no stinkin' cams), and my trusty Cubs baseball cap for a helmet.




Lordy, I miss this website. I really, really miss the discourse on thought-provoking issues. You know -- the intelligent questions raised by experienced climbers. If only I could spend less time dealing with issues at the office, I could see threads like this all day.


That would be so totally, uber cool.

Does anyone know what safety factor most climber go by ?

Do you build your anchor so it could handel your weight or you build it so it could take 10x of your falling forces ?

if you ask me, why fire and rescue people use high rating gear, I could easily tell you that In USA fire services , the minmum safety factor is 15:1 and generally, a fire man is consider as 1 kN.If he is going down the line to rescue another man who is 1KN, his biner has to be at least 30 KN or more to support two. You will not see a fire man on a climber biner rapping down the side of building if his biner is rated to 18KN . The 15:1 safety factor, unofficially has been set as an standard by agencies such as NFPA which overseas some of the standards for rescue gear.

What kind of safety factors standard do you have out there for climbers ?

3:1 , 5:1 ?

Does anyone know what safety factor most climber go by ?

Do you build your anchor so it could handel your weight or you build it so it could take 10x of your falling forces ?

Forgive me if I am wrong, I'm a little rusty and my rigging / engineering book is at the firehouse. Is it not true that 15:1 is not static figure, but rather can be downgraded depending on the situation? What I mean is that if an anchor will not be subjected to more than one person it can be built at a 10:1 margin? I know its rare that the rescuer and victim wouldn't be on the same line, but I think this is true.

What I can contribute that I know is true is that NFPA does not recognize kN forces in their calculations, but rather only static weights (3000 lbs, etc.).

kN is just a unit of force, just as the pound is. 1 kN = 225 lb (approximately).

Jay

I realize that is true, so I should clarify. What I am trying to say is that although they can be converted back and forth to accommodate either unit, the NFPA will never publish any regulation using the kN unit. I believe this is because kN has become synonymous with dynamic forces while pounds are associated with static loads.

No. There is no such thing as "dynamic force." There is just "force." I would think that the reason that the NFPA does not use the unit kN is because they are a U.S. organization, and hence they use the U.S. unit of force, the pound.

Jay

No. There is no such thing as "dynamic force." There is just "force." I would think that the reason that the NFPA does not use the unit kN is because they are a U.S. organization, and hence they use the U.S. unit of force, the pound.

Jay

In climbing, there are no such standard or at least no one builds an anchor or uses a biner with such safety factors in mind. Most people feel that two cams in the crack and leaving one draw on TR does the job and there they go off the wall.

I am confident that most manufacturer know why they build their gear in such ways, but does public has any idea why these ratings are for ?.

Do we feel safer with a gear rated 5 times more than what we could generate during a fall ?

Thanks for the correction. When I said dynamic force, I think I should have been saying shock loading. Is shock loading measured differently than other kinds of force, i.e. a different unit? I'm not arguing I'm just asking, because the way I understand it a 225 lb or 1kN person does not weigh in at 1kN when loading the rope immediately after a fall, while they still weigh 225 lbs. Or am I misusing weight for mass in that scenario?

And yet we still hear of gear failures. I know I have heard of biners snapping on slacklines, harnesses failing, cams breaking, ropes snapping... etc etc I will give you that most of this was probably improper use and/or excessive wear and tear, but mfg know this shit happens and therefore build to account for a certain degree of stupidity/cheapness/laziness/misuses by the users. Also it's nice to have gear that is OBVIOUSLY way too worn to be using before it fails structurally.