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Are leg loops rated full strength?

Marssan

21-Apr-2009
10:09:35 PM

The recent discussion re: abseiling with a backup autoblock/prussic attached to a leg
loop (on the accidents forum) reminded me of a comment my instructor made during a
self rescue course I did a while ago.

As he observed me negotiate a knot on abseil he said I shouldn't have my prussic
attached to a leg loop because they aren't full strength like the waist belt.

I have owned many harnesses and taken many falls on all of them and have never seen
any evidence of the leg loops deteriorating or failing. My own experience is clearly not
level 1a evidence but it makes me wonder:

Has anyone ever blown a leg loop?
What parts of the harness are full strength? Anyone know?

BR

21-Apr-2009
10:26:00 PM

Haven’t you seen cliffhanger ........

just kidding,
i have never had one of the loops blow out on me, but
about 15 years ago after seeing that movie, some friends and i did some testing on harnesses. I had a Black Diamond (don’t remember the model) it was around the $100 mark and we tested the belt and loops with small falls ~1m with double body weight ~120kg being just tied into the belt and then just tied in the leg loops and they all held, not the smartest thing to do in hind sight ..... and we were roped in and not using prussic cord.

I have a Petzl Calidris harness now and do remember reading that Petzl did rate the strength on the belt, harness and loops...
but its good food for thought.

Paul

21-Apr-2009
10:37:51 PM

On 21/04/2009 Marssan wrote:
>The recent discussion re: abseiling with a backup autoblock/prussic attached
>to a leg
>loop (on the accidents forum) reminded me of a comment my instructor made
>during a
>self rescue course I did a while ago.
>
>As he observed me negotiate a knot on abseil he said I shouldn't have
>my prussic
>attached to a leg loop because they aren't full strength like the waist
>belt.
>
>I have owned many harnesses and taken many falls on all of them and have
>never seen
>any evidence of the leg loops deteriorating or failing. My own experience
>is clearly not
>level 1a evidence but it makes me wonder:
>
>Has anyone ever blown a leg loop?
>What parts of the harness are full strength? Anyone know?
>
>

It would depend on the harness and what standard(s) that they are designed / tested against.
The webbing on the leg loops of some of my harnesses are narrower than the webbing on the waist (half the width on one harness). This might possibly mean that it is half the strength?
The leg loops buckles on most bod style harnesses are not rated. Although they are not primarily load bearing.

But think about it, how much force could you put on the brake end of the rope during an abseil? How much force does your hand apply when abseiling? It isn't that much, even if there is a major shockloading some how most of the force would be held in the abseiling device, like belaying a lead fall.

tastybigmac

21-Apr-2009
10:59:02 PM

irrelevent. you are not putting your body weight on the leg loop. the prussik is holding the brake rope in a braking position and the abseil device attached to the belay loop is holding most of the load. if you clip a backup knot through the leg loop that is another story.

dave

21-Apr-2009
11:10:09 PM

On 21/04/2009 Marssan wrote:
>Has anyone ever blown a leg loop?

Here is the answer to your question:

From this topic:
http://www.chockstone.org/Forum/Forum.asp?Action=DisplayTopic&ForumID=6&MessageID=9127&PagePos=&Sort=&Replies=82&MsgPagePos=40
(pics down the bottom of this page)

kieranl

23-Apr-2009
12:24:07 AM

You'll notice from the photo that the bit that loops around the leg, where the backup prussick would be clipped, is intact.

muki

23-Apr-2009
12:38:45 PM

And I also notice that the central power point where I would attach my back up prussic is totally
undamaged whatsoever, wow that's enlightening, thanks K

IdratherbeclimbingM9

23-Apr-2009
1:52:29 PM

Also from that thread it should be noted why that harness ended up in that condition.

On 4/02/2009 skip-skip wrote:
>Here is an example of an only moderately worn tie-in point failure. I
>was back jumping a route in Nowra, to clean it, taking hard falls. There
>was a loud popping/ripping and a feeling of being strangled by the waist!
> Now, the harness was worn, but I was sure it was still within its limits.
> Take note people!

... and a reply that perhaps sums up the thoughts of many.

On 4/02/2009 tnd wrote:
>Repeatedly over a short period subjecting harness and rope to high load
>in that manner is hardly a sensible climbing practice. Sounds like an accident
>waiting to happen.

Marssan wrote;
>What parts of the harness are full strength? Anyone know?

Depends on the brand, but most commercially available harnesses are rated for the task. Some more so than others, particularly if they have an industrial application.
The strongest climbing harness I know of are the Metolius Safe-Tech series. I note that they mention rated gear loops and haul loop, but no rating for the leg loops, but covered by this statement...
>
Wherever possible, each component is engineered to withstand a load of 2250 lbf (10 kN). This is typically the maximum impact force rating of a modern climbing rope.
>2250 lbf (10 kN) Spectra gear loops
>3600 lbf (16 kN) Spectra rope locator
>3600 lbf (16 kN) rear haul loop
>1500 lbf (6.6 kN) leg loop elastic

Disclaimer: I have no commercial affiliation with the company/shares in/ etc etc.

muki

23-Apr-2009
5:52:21 PM

Looks like a stitching failure to me.

There are 9 messages in this topic.