minimum Kn for climbing

[czhey]

 

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!

 

I thought you needed a safety factor of 20 where a life depends on it? If so what if you had a 150Kg climber? would they need 30Kn equipment?

 

From a sheet in front of me: "Generally a SWL of 10:1 is recommended. This can be increased to 20:1 for more extreme situations where property or lives are at stake" might be talking about rigging though?

[shabz1978]

 

I thought you needed a safety factor of 20 where a life depends on it? If so what if you had a 150Kg climber? would they need 30Kn equipment?

 

my point exactly!! how can these things have a set, pre-determined value, when everyone is different. surely it makes more sense to decide on a safety factor and then work out what rating you need for your specific requirements.

 

if you look at my avatar, you'll see that i'm a bit of a lard ass. i weigh 110 ish kilos, if i'm rescuing someone of my own portly stature, then surely i would need at least a krab that had a rating of 24kn (110kg+110kg+20kg for gear =240kg = 24Kn min)

 

but the other lad at work (he doesn't mind being called a moron) weighs maybe 80kg so, if he's rescuing someone of his own size, he needs a krab thats rated at a mere 18Kn (80kg+80kg+20kg= 180kg = 18Kn)

 

if that doesn't make sense then i'll chip all day in my underpants wearing a dunce hat!

[Craig Johnson]

All that chris said, plus 5000lbs is just under 23kn which is why our USA friends cant climb on our euopean 22kn gear.

 

well put chris nice to know that your out there lurking

[Rod]

 

 

if that doesn't make sense then i'll chip all day in my underpants wearing a dunce hat!

 

 

thats it im off sick tomorrow dont need to be seeing that.

[Rupe]

There seems to be soem miss quoting going on above, but anyway you don't need a safety factor 20, 10 is plenty but if you want to use 20 then thats fine.

 

Shabz, with your working you say that to rescue two of you needs krabs 0f 24kn. I see how you arrived at that figure, but your combined weight is 240kgs which is fractionally over the swl of the (22kn gear) but still well within the MBS.

 

Continually going over the swl increases the "cycles to failure" and is not good, but theres is nothign wron gwith rescuing another guy your size in an emergency.

 

Afterwards you may want get your gear lolerered again as it was subjected to a load above swl but the guy you rescued would still be alive.

 

Chris has pointed out all the technical stuff better than anyone else can, the rest of us should relax and get on with our jobs becasue 22kn is plenty and guys like chris have done extensive testing of various situations. We don't need to get too bogged down with it all.

 

HAvign said that, if I hired a 150kgs climber I might get him to use steel 30kn krabs!!!!

[arnoldbuchsassinger]

I did not quote 10 * as the rating, if you read the Petzl website, it says EN362, 15Kn on the PPE inspection, a factor of 10 on 1500Kg is 150Kg. I only joked that if you have a safety margin on climbing and lifting you are well with those margins. However for work we must go with the standard recommendations. If people take for granted everything they read on a website, we'd be doing treecare by wikipedia. Perhaps you do!!

[Sciadopitys]

Continually going over the swl increases the "cycles to failure"

 

Continually going over the swl DECREASES the "cycles to failure" didn't ya mean!?!

 

Personaly, i think we have to be sensible about these things, if an American wants to use a European product rated at 22kn then imo there is no bloody reason why not, apart from somebody sat in an office writing ANSI documents. 22kn or 23kn is gonna make no difference in the real world! I know Americans tend to be larger than us Europeans by a few lbs, but come on!!

 

And, on the other hand, i actually have a few pulleys manufactured in the States by CMI, and they are bloody good pulleys, one is a micro-mouse pulley (like hitch climber but only 2 holes!) and this is rated at 7000lbs / 31.1kn and doesn't have a CE mark so cannot be used in Europe, yet a hitch climber pulley is rated at 24kn, so i can use it in Europe. Explain!!!! Its a load of rubbish, good enough for Yanks, good enough for me! And vice versa! If its rated, its rated - End of story! (in my opinion)

[Rupe]

Sure yes, thats what I mean.

 

An increase of cycles to failure decreases the cycles to failure that you have left.

 

Takes you towards failure. Something like that.

[Chris Cowell]

Sciadopitys

 

One key point about the strength of PPE is that your death shouldn’t be caused by its’ failure. Or to put it another way, you should be dead before it fails! Whether a pulley is rated to 24kN or 31kN is largely irrelevant, because anyone attached to it is likely to be cream crackered long before that force is reached.

 

Another point to consider is that manufacturers adopt their own margins of safety. A product rated to 22kN may fail just above, or significantly above, that force depending on company philosophy. In the case of the Hitch Climber, the breaking load is 10+kN higher than its’ rated strength.

 

CE/EN is a system that demands independent verification by a notified body. Many US products that carry an ANSI marking may be self certified by the manufacturer. It is my understanding that there is often no requirement for independent verification for PPE products sold in the US market. However, the last thing a manufacturer wants is a claim resulting from an accident, so they are unlikely to make false claims. My point is merely that the two systems are not the same, and of course neither is perfect! One system is, however, clearly more expensive to administer than the other and its’ presence is a legal requirement if you want to sell PPE within the EU.

[Ray]

As a rock climber i can give you a reason for the 24kn min. In rock climbing we climb above the gear so if we fall we have the potential to generate quite high forces. The maximum force a climber can theoretically generate is 12kn, that would be falling say 20m on 10 of rope, called a factor 2 fall. When the load comes onto the karabiner the pulley effect means that an equal force is applied down both sides ( minus the friction) so the karabiner could in theory be subject to a 24kn force.