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Safety factor on Carabiners


Jamie

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I was just looking at my Petzl catalog and I notice the Owal oval carabiner is rated at 24 kN. Does that mean you might expect it to fail around there, or is there a safety factor so 24kN is like a working load and there is no problem using it at its limit? If there is a safety factor what is it? x2? x3? etc...

Just curious.

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BD Quality Control

 

3 SIGMA

 

ISO 9001

To rate our climbing gear with a meticulous degree of accuracy, Black Diamond uses a rigorous, best-in-the-industry rating standard called Three Sigma. By batch testing our climbing equipment following 3 Sigma methodologies, we can ensure that there is a 99.87% probability that the strength of any item taken from the same batch will be above the rating. And though the rigorous 3 Sigma testing method results in a rated strength that is three standard deviations lower than the average value found during testing, we feel climbing hardware requires testing with an absolutely consistent and conservative approach to ensure the high levels of quality you have come to expect from Black Diamond.

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By batch testing our climbing equipment following 3 Sigma methodologies, we can ensure that there is a 99.87% probability that the strength of any item taken from the same batch will be above the rating.

 

Given that they don't tell you the width of the sigmas, all this means is that the breaking strength of your 24-kn-rated biner could be 24.01 kn

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but they do, if you remember statistics!

 

"3 Sigma testing method results in a rated strength that is three standard deviations lower than the average value found during testing"

 

Well but what distribution do those three sigmas follow?

 

In other words for the same mean you can have two different standard deviations. High Cv = high sigma relative to mean and vice versa.

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  • 3 years later...

Thanks kurthicks.

I'm that is quite helpful. I'm a safety consultant and sometimes have to evaluate the likelihood of climbing gear failing. Of course the cause of accidents is much much more likely to be human failures (unsafe acts) rather than equipment failures (unsafe conditions).

 

Edited by Jamie
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  • 2 weeks later...
i would like to see how you can get any normal situation to reach 24kn on a biner. I forget the actual numbers, but I thought a fall factor 2 was the most force achieved while climbing and that resulted around a 16kn force.

 

Won't a tight slackline get close?

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i would like to see how you can get any normal situation to reach 24kn on a biner. I forget the actual numbers, but I thought a fall factor 2 was the most force achieved while climbing and that resulted around a 16kn force.

 

Won't a tight slackline get close?

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