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Pros/cons of PAS for use at belay/rap stations?

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Re: Pros/cons of PAS for use at belay/rap stations?

Postby Kahuna » Fri Aug 31, 2012 5:57 pm

^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

The shock load test by DMM is a leader fall situ.

Belaying is still a dynamic situ regardless if using a Direct or Indirect belay scenario imo.

A belayer will never have the load energy generated onto them or the Direct Belay set up that is portrayed in the DMM test. Never.

If they do, they have no business belaying.
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Re: Pros/cons of PAS for use at belay/rap stations?

Postby TimB » Fri Aug 31, 2012 6:08 pm

mattyj wrote:
A5RP wrote:A standard 24-36" runner that is already on ones rack, of any type, girth hitched to your belay loop for the entire multi-pitch rap evolution, will do. This is a static and not a dynamic situ. Thus the dyneema vs. nylon issue is a moot one.


This is what I do too, but I think you and Wastral are missing the point. There are two separate issues: convenience and safety. I don't find a PAS convenient enough to justify the weight/bulk, so I don't own one. For someone that does lots of climbing on single-pitch bolted routes, I understand how it could be convenient, especially if you're frequently untying to clean a TR and thread the rope for rappel. You wouldn't bring ascenders on a free climb for self rescue and you wouldn't jug el cap on prusiks - different styles of climbing call for different tradeoffs w/ respect to gear.

From a safety perspective it's irrelevant whether you tie in with a PAS or a dyneema sling; the issue is how dyneema handles accidental shock loading relative to nylon. So-called "static" situations are exactly where the risk is highest - eventually you'll do something that turns it into a dynamic one, like the incident TimB references. You notice a knot in the end of the rope and scramble to grab it before your partner pulls it out of reach, or more commonly, how many people sit on the edge of a cliff and clip a bolt at their feet when setting TRs? People who are new to climbing look at that and go "it's a short fall, it's safe" rather than "that's a factor 1 onto static gear".

Drop tests show that this can be a serious issue. Yet so far, it's not a major cause of accidents. Maybe the drop tests are unrealistically harsh, maybe climbers just don't tend to fall on their static tie-ins. I see nothing wrong with clipping in using dyneema - sling or PAS - so long as you're mindful of the slack, and I do it myself. But telling someone to use a dyneema runner instead of a PAS does nothing to address the original safety question.

Tim, if I build a trad anchor and clove myself in with the rope, I generally don't bother with a backup tie-in method. If I do want one, I go just downstream of my clove, tie and overhand on a bight, and clip that to my anchor somewhere. I don't personally feel the need to back my rope up.


Matt, I should have stated that most of my use thus far of the (Metolius) PAS has been in a bolted, TR scenario. I can see how simply tying into the rope on a trad climb would be the way to go. In fact, on my first multi-pitch trad climb a few weeks back, my instructor told me I wouldn't need my PAS- I simply tied into the rope.

Also, now that I think about it, what are the chances of pulling a bolt if you were to fall using a PAS? Not very likely, I should think. However, it sounds like such an event would expose me to some pretty high fall forces.

Anyhow, I appreciate the response.
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Re: Pros/cons of PAS for use at belay/rap stations?

Postby mattyj » Fri Aug 31, 2012 6:35 pm

A5RP wrote:The shock load test by DMM is a leader fall situ.


Huh? The DMM test simulates someone clipping into a bolt with a dyneema runner and then accidentally falling on it. The concern that it brings up has nothing to do with leader falls or belaying. There's a million things I'd rather do than sit here and get in a pissing match over this, but for the sake of others reading this thread, can you explain what you're saying and why it negates the concern that some people have about clipping directly into an anchor with spectra/dyneema?

Tim, yes, in a real-life scenario the bolt and PAS will probably come out okay. It's your pelvis you ought to be worried about.
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Re: Pros/cons of PAS for use at belay/rap stations?

Postby Kahuna » Fri Aug 31, 2012 6:40 pm

mattyj wrote:
A5RP wrote:The shock load test by DMM is a leader fall situ.


Huh? The DMM test simulates someone clipping into a bolt with a dyneema runner and then accidentally falling on it.



Pissing contest... nope. Your reading far too much into the premise of this test Mattyj.

I am well aware of the DMM test as I posted it back in 2010 when it first came out. No where in the DMM test is static tie in while "BELAYING/RAPPELLING" addressed. No where.

The entire test is based on a dynamic "Falling" situ.

At DMM’s test-tower we took a look to see what implications this difference has for a dynamic loading on to a Dyneema® sling


If any belaying or rappelling situ turns into a dynamic "FALLING" one, the individual belaying/rappelling has absolutely no business doing so as evidenced by the following statement in the test brief:

"If you do use slings then ensuring there is no slack in the system is paramount."





Thus your ref is a moot point.
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Re: Pros/cons of PAS for use at belay/rap stations?

Postby Burchey » Fri Aug 31, 2012 7:31 pm

I've been using the Purcell for a while - even though it gives a bit, the idea is to not create a situation involving a big static shock. It backs up my clove hitch, and I love that I can clip and then quickly let out a little or take in depending on how far back I need to lean, etc...easy to equalize my clove if I'm tied to different points. Serves as bail cord if I get in over my head on a 2 pitch 5.3 and need to rap off.

I really like it when climbing leashless - if you get a little desperate, place a tool high, clip it and then take in the slack. No choosing-the-right-ring nonsense like with my old PAS.
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Re: Pros/cons of PAS for use at belay/rap stations?

Postby mattyj » Fri Aug 31, 2012 8:28 pm

Yes, the entire test is based on a situation which should never happen. Doesn't mean it will never happen. People aren't perfect and occasionally make mistakes. When possible, we try to design our safety systems to accomodate some degree of human error - this is hardly unique to climbing.

Nylon is more forgiving of this specific mistake. Doesn't mean that you shouldn't use spectra - I do. There are hundreds of ways you can die out there and we can't be perfectly protected from all of them - we need to pick and choose which risks we manage and how.

Sometimes I tie a knot in my rappel ropes. If I'm concerned about them getting snagged, then sometimes I don't. Saying "any individual who could rappel off the end of their rope has absolutely no business rappelling" doesn't really help me make an informed decision.
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