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Retired Krabs

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Steven Martin 07 Feb 2005
I was looking at some old threads and one mentioned a manufacturer's recommendation that krabs should be retired when they are 10 years old- (though this was not the main point of that thread and was not discussed thoroughly at the time.)
I would like to discuss it thoroughly, as I have some krabs that are over 30 years old, and a couple of steel ones that must be 40 years old.
1. Why should they be retired? Just age or through usage/loading?
2. Any evidence, through testing, case histories?
3. All types? ie wires, ovals, Ds, screwgates, twistlocks etc. Size?
Do similar retirement ages axist for ATCs? or fig 8 descendeurs? or Friends? or hexes?

from a slightly worried old man.
In reply to Steven Martin:

I am a terrible cynic and tend to assume that manufacturers say these things to stop people suing them over old gear and to encourage us all to spend more.
I would think a better test would be to inspect the gear regularly looking for signs of wear and metal fatigue.
 Mike C 07 Feb 2005
In reply to Steven Martin:
Took a 25ft fall last year onto a Clog 2200kg krab that was approx 25yrs old. It opened allowing the gate to spring out, then it bent back to almost it's original shape. It did hold the fall OK, but I have retired all it's peers just to be on the safe side.
stu_dent 07 Feb 2005
In reply to Steven Martin:

Eyeball this:
http://www.thebmc.co.uk/safety/tech/articles/tech_a3.htm

Impartial artical.

Even if you have not used the kit, hardware (all metals for that matter) oxidise (rust) on contact with even humid air. Even with good storage you can't stop corrosion.
AnthonyB 07 Feb 2005
In reply to Steven Martin: I'd retire them after about 20 years even if they're fine, better to be safe than sorry
In reply to AnthonyB:

One thing that would worry me about very old metal gear (over 20 years or so) is not knowing what manufacturing standards were used at that time. The thing about gates opening on older crabs is interesting.
OP Anonymous 07 Feb 2005
In reply to Steven Martin:

The reason manufacturers now state an age all modern gear should be retired at is due (I believe, though I am prepared to be shot down in flames by some of the legal folks that frequent these forums) to some legislation which requires these things to have such a date.

Now obviously for things such as ropes etc any such figure is meaningless, as the rope's lifespan is so heavily dependant on what you do with it. Metal stuff is similar in that a lifetime of sitting in a dry cupboard will be substantially longer than a lifetime of regular climbing at Gogarth.

The estimate of 10 years is likely to be a conservative figure. But it's entirely your decision, after all it's your posterior on the line.

Victim of Mathematics

NB can one rule out a cynical ploy from manufacturers to make you buy lots of shiny new stuff every 10 years? I hope so.
 Horse 07 Feb 2005
In reply to Steven Martin:

It's to do with product liability legislation.
 Dave Stelmach 07 Feb 2005
In reply to Steven Martin: I've had some of mine for 20 years & they still work OK. Depends on how much stress they've had like all of us!).

First glance, I thought you were referring to retired RAF personnel.
 Horse 07 Feb 2005
In reply to stu_dent:
> (In reply to Steven Martin)
>
> Even if you have not used the kit, hardware (all metals for that matter) oxidise (rust) on contact with even humid air. Even with good storage you can't stop corrosion.

At best a gross oversimplification, at worst plain wrong. Many metals do not corrode in contact with humid air, some do and the resultant scale is protective, so do and continue to do so.

Good storage will and keeping things clean will prevent corrosion. Aluminium alloys need not corrode at all if correctly looked after.
epik 07 Feb 2005
In reply to Steven Martin:

its to do with the CE mark! to get any peice of PPE - personal protection equipment (which carabiners come under) certified they have to be supplied with full instructions including care and maintanance including retirement age. think all manufacturers put 10 years for metal items (no doubt a figure suggested by the CE testers) but as for how they come to that figure god knows! still even if you only climb every other weekend its only 2p for a days climbing!
In reply to Mike C:

> Took a 25ft fall last year onto a Clog 2200kg krab that was approx 25yrs old. It opened allowing the gate to spring out, then it bent back to almost it's original shape

Have you still got those krabs Mike? It would be interesting to know exactly why it failed. Had you thought of sending it in to the BMC for analysis?
Sorry if that sounds cheeky, not everyone is such a nerd as me!
O Mighty Tim 07 Feb 2005
In reply to Alison Stockwell: 2200KG sounds like a much weaker design load than the current kit? Especially if it's only rated for static, rather than dynamic loading.
Fall factor comes into things as well.
It may have performed BETTER than design, due to a higher than rated impact loading.
Without all the data, it's just a rumour...
Steven Martin 07 Feb 2005
In reply to O Mighty Tim:

> Fall factor comes into things as well.

How can fall factor affect the load on a krab? (assuming the total load is x what difference is there to a static load of x?)


In reply to O Mighty Tim:

No dynamic fall would come anywhere near 22kN without the person dying. Most likely it would be about 8 I would guess, though others will no doubt correct me if that's wrong. That's why I was wondering if there was something else about the krab. A design fault or subtle damage maybe.
 SouthernSteve 07 Feb 2005
In reply to Steven Martin:
I retired all my 1985 Clog Krabs this year - they looked scratched to pieces, but seemed otherwise OK but after using more modern ones they were heavy and less easy to handle. As I remember the 2200 plain gates and 2500 screw gates were not UIAA rated, you had to buy the 2500 snap or the 3000 screw to achieve those standards. Still they were good, have lasted well and were so much better than their competitors at the time.
Stuart Robinson 07 Feb 2005
In reply to epik:

> its to do with the CE mark! to get any peice of PPE - personal protection equipment (which carabiners come under) certified they have to be supplied with full instructions including care and maintanance including retirement age. think all manufacturers put 10 years for metal items (no doubt a figure suggested by the CE testers) but as for how they come to that figure god knows! still even if you only climb every other weekend its only 2p for a days climbing!

Thats seems a lot closer to the real situation that any other I have seen.

I believe manufacturers must now state an expected lifespan, and whilst the lifespan may not be legally compulsory, if the bit of kit were to fail AND it was out side its expected lifespan then it could make for difficulties.

This situation puts group users of kit in a difficult position, even if the kit is very lightly used and well stored (such that its lifespan may well be far in excess of 'only' 10 years) you may be forced to replace it anyway.

 Horse 07 Feb 2005
In reply to Stuart Robinson:

With things like krabs one could establish pretty quickly the cause of any failure, no matter what the age. If this could be shown to be an manufacturing defect rather than due to wear and tear or something induced through misuse/abuse then the manufacturer would be in very difficult position if the failure occurred within normal life. Given the lengths the manufactuers go to to ensure the quality of the product I think this unlikely. The responsibiliy is with the use to make sure the thing is fit for use. Of course that is the logic which would go out the window when the lawyers hove into view.
Stuart Robinson 07 Feb 2005
In reply to Horse:

> Of course that is the logic which would go out the window when the lawyers hove into view.

Of course, which was the point I may not have made very well.



 Horse 07 Feb 2005
In reply to Stuart Robinson:

This was posted on another thread last year about cosmetic seconds perhaps reiterating the steps that good manufacturers take.

Horse

Thanks for the mail.

DMM were the first hardware manufacturer to meet ISO 9001 and the first to adopt the 3 sigma quality standard.

We use only the best Aluminium stock - mainly 7075 and a little 6082. Every batch of Aluminium is isolated at Goods In until independently tested.

Every production batch is traceable back to the original bar stock. Every single operation on every batch is quality controlled and recorded.

The heat treatment is totally automated using software that was developed inhouse because we could not find a suitable program on the open market.

After heat treatment every further operation is again quality controled and recorded.

After final assembly every item is again visually checked and all moving parts operated.

Thus, for example, every Wire Lock biner receives 36 checks during its production.

After over 23 years of producing hardware DMM have the production of quality climbing goods pretty well dialed, evidenced by the fact that we make metalwork for both Wild Country and Petzl.

So where does all the wasteage come from?

After forging the excess flash needs to be clipped from the body of the item - this flash accounts for a large volume of the waste in the skips.

The majority of component /finished items in the skips are due to the 3 sigma batch testing. This requires the testing, both non-destructive and destructive, of a lot of kit. Once kit has been tested it can not be sold.

DMM also work closely with the governing bodies to try and prempt problems and this involves quite a lot of testing/destroying of kit.

In addition developement programmes often generate a lot of wasteage - thus items can appear in the skip that look normal, but the forging may not have filled out completely or the radiuses might be too tight.

Also mistakes do happen - that is why our QA is so thorough - and sometimes that means components have to be to thrown away.

However most of the wasteage is incurred ensuring that our products are safe to use.

Quality and, in this case safety, is not cheap.

I hope this clarifies the situation

Regards

Simon Marsh

DMM International
 Mike C 07 Feb 2005
In reply to Alison Stockwell:

I most certainly do still have it, sort of a lucky charm as if it had failed anymore I would have decked it. JoHNY watched my fall & all he could focus on was the pointy rock beneath my back.
Not really bothered getting it analysed as it is pretty old, but if you want to be really nerdy drop me an email & I can forward a pic of it. Basically it looks fine now, except the gate is on the outside.
Mike
stu_dent 08 Feb 2005
In reply to Horse:

'At best a gross oversimplification'

Very true, really could not be bothered to type much more on this occasion, especially when most people do not care for the ins and outs of chemistry, would not want them switching off.
 Timmd 08 Feb 2005
In reply to Steven Martin:I've got some crabs i bought a few years ago or five years ago,i won't retire them when they're ten years old because i've not used them,i might stop using my Dad's 20 year old ones after reading about the fall further up though,maybe the metals now used would stop that happening,i'm not a metalogist though.
In reply to Timmd:

That echoes my thoughts more or less. I don't think under ordinary circumstances metals can just deteriorate over time without some external evidence of corrosion or wear that would show up in a routine visual inspection. Hairline cracks due to impact damage are another matter, but that's a different discussion.

Horse's post about the rigorous manufacturing and testing standards of modern equipment does raise doubts about older gear that may not have been through those processes. After all, manufacturers learn from earlier inadequacies.

In the absence of further information on older gear I think that's a good reason to retire it. However, I'd still be inclined to use newer gear for personal use well beyond it's official retirement date. That's assuming some other good reason not to doesn't emerge.

Group use is another matter. Then we all have to cover our behinds.
In reply to Mike C:

How much of a nerd do you think I am! Whoever would want a photo of a karibiner? Especially after you've described it so well.

On second thoughts; well, OK then. Photos like that make great visual aids for people who are inclined to waffle on about gear to poor long-suffering newbies and the like. Now what sort of nerd would do that?

:-P
 Horse 08 Feb 2005
In reply to Alison Stockwell:

Credit where it is due, the post was a copy from one made by Simon Marsh of DMM not me. I suspect that the procedures described have been in place for a long time and gradually fine tuned over time.
 Norrie Muir 08 Feb 2005
In reply to Steven Martin:
> I would like to discuss it thoroughly, as I have some krabs that are over 30 years old, and a couple of steel ones that must be 40 years old.
> from a slightly worried old man.

Dear Steven

The krab on my Whillan's harness is as old as your krabs, and I am not worried. What has conserned me is my harness has shrunk.

Norrie
In reply to Norrie Muir:

That's interesting. My husband says the same about his shirts. Must come down to environmental factors.

 Norrie Muir 08 Feb 2005
In reply to Alison Stockwell:
> (In reply to Norrie Muir)
> That's interesting. My husband says the same about his shirts. Must come down to environmental factors.
>
Dear Alison

Factors, like a wife who feeds her husband too well.

Norrie
In reply to Norrie Muir:

Lol! Not in our household. My husband and kids have to forage for themselves. I'm far too busy climbing or talking about it.
 Norrie Muir 08 Feb 2005
In reply to Alison Stockwell:
> (In reply to Norrie Muir)
> Lol! Not in our household. My husband and kids have to forage for themselves.

Dear Alison

Then it could be the Fish Supper or Indian meal, before he gets home that does it.

Norrie
 Mike C 08 Feb 2005
In reply to Alison Stockwell:
> (In reply to Mike C)
Photos like that make great visual aids for people who are inclined to waffle on about gear to poor long-suffering newbies and the like. Now what sort of nerd would do that?
>
> :-P

You tell me
Email me through the site & I'll send a pic to your email address tonight when I get home (can't send attachments through UKC).
Mike

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