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So the UIAA sets a major fall (fall after which to retire your gear) to be a fall factor of 1.77.

Now I was wondering what would count as a major load (load after which to retire your gear) ? 50 kN ? More? Less ?

In the petzl document "tips for protecting your equipment" they don't seem to make a distinction between metal gear and ropes. So is that the same for all ?

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@Liam, I hope the edit suffises ? –  Nick Aug 29 at 9:30

2 Answers 2

up vote 4 down vote accepted

Your equipment should all come with a Kn rating. this is the force that that piece of gear will hold (often in what direction).

So looking at a standard carabiner:

enter image description here

  • This will hold 25Kn when loaded correctly (from the base to the top)
  • 9Kn when loaded correctly but with the gate open
  • and 7Kn when loaded incorrectly (though the screw gate)

All pieces of gear should come with these ratings written on them somewhere or in the documentation included (this includes ropes). Different pieces of gear will hold different kns and they all vary slightly so you need to check the rating of that particular gear.

For another example here are some brass nuts. You can see the ratings below:

  • Brass Chock 1-2 : 6 kN, Brass Chock 3-4 : 7 kN
  • Brass Chock 5-6 : 8 kN, Brass Chock 7-8 : 9 kN

Rock strength

One other thing to bear in mind is the strength of the rock. There is no use putting a 20Kn cam into soft brittle rock. The cam may hold the fall but if the rock gives way it doesn't matter.

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true your system is only as strong as your weakest link. But as a Major lead I should simply count the maximal load ? In the case of the D-carabiner that you posted it would be 25 kN when loaded correctly ? –  Nick Aug 29 at 9:50
    
That's complicated and related to your other question. If you fall when leading the fall factor effects the load. Each piece of gear in the system will take some of that load. How much load depends on where it is in the system and what it's connected too, etc. If a piece of gear "pops" then the next piece of gear will take a second jolt of load, but this will be less than the one above it (as some of the load will be taken by the gear before it pops) –  Liam Aug 29 at 10:01
    
Yes the carabiner above will hold 25Kn when loaded correctly. If it's attached the nut that only takes 8Kn though then the nut will pop at 8Kn. The carabiner won't break but anchor will obviously be compromised at this load. On the other hand if it was attached to 3 nuts and the load was evenly distributed then the system itself comfortably take 25Kn. –  Liam Aug 29 at 10:03
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25 Kn is a lot BTW! 25Kn is 2549Kg static force –  Liam Aug 29 at 10:06
    
Indeed that's a lot. To be hones I don't think I ever want to expierence any load above 5-6kN :p. –  Nick Aug 29 at 13:24

In a fall, roughly the same load is applied at every point along the rope, at the climber's harness, and at the anchor. "Roughly" means that this is an approximation where rope drag is negligible, the mass of the rope is negligible, and we're not taking into account the geometry of a redundant anchor. (If the anchor is equalized, the load could be shared by the different pieces, but if the angles aren't favorable, the load could be increased.)

The fall factor and the maximum load are not independent parameters. WP has a formula that expresses the maximum load in terms of the climber's body mass and the fall factor. Since people's body masses are all on the same order of magnitude, the fall factor almost completely determines the maximum load.

Physically, the maximum load is probably the most relevant thing that determines what bad things will happen to the rope, climber, and gear. (It's also possible that total energy dissipation could make a difference.) But since maximum load is essentially determined by fall factor, all you really have to worry about is a single number, which is the fall factor. This is good, because fall factors are easy to estimate while climbing, but it's not practical to estimate while you're climbing how big the dynamic load will be from a lead fall.

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