Accident at Haus Rock near Keystone, CO (Petzl Shunt accident)

Ryan Never climbs wrote:

i’m really surprised the info from the rope access world didn’t make it over to the climbing world. 

Did that info from the rope access world include failures where the rope pulled completely out of the Shunt? Or just incidents where someone grabbed the shut or something jammed the cam level upward so the Shunt remained on the rope but didn't grab, allowing the rope access technician to fall? 

(Edit): Oh I found some stuff on rope access testing and see... I didn't see any previous (before 2021) known cases of the Shunt detaching from the rope just because it inverted in a fall (Scorpion Catch). But testing back in 2001/2002 showed it could fail to grab and pop off the rope when it hit a backup knot. The documented failures in rope access were...

1. If user grabbed Shunt body or grabbed rope above the Shunt in a fall
2. Trailing Shunt on a tow cord to keep it higher and pull it down reduced risk that user could grab shunt body or grab rope above Shunt in fall, but if user held onto and failed to let go of the tow cord, Shunt would fail (continue falling). Petzl at one point recommended specific training to RATs to make sure they let go of the tow cord and didn't grab the Shunt body during a fall.
3. 2001 Lyon testing showed Shunt took a long time to stop a fall with heavy weight on thinner rope, and if it hit a backup knot before stopping, could pop off the rope.
4. 2002 testing showed with a 100kg load and factor 1 fall, all the devices tested performed okay on 11.1mm rope.   But with factor 2 falls (100kg weight falls from 1m above device on a 1m lanyard), Shunt performed well on a PMI 11.1mm rope but slid too far--sometimes into the backup knot--on a Beal 10.1mm rope.  With a 200kg (2 person load) and a factor 1 fall, the Shunt also sometimes hit the knot and came off the rope on a Sterling 11.1 and Bluewater 10.6mm ropes, but it arrested the fall okay on the PMI 11.1mm and Sterling HTP 11.6mm ropes. The testers concluded that the Shunt was fine as a rope access fall arrestor (backup device) for a single person (up to 100kg) load using a static rope of at least 11.1mm measured diameter, and if the user was trained not to grab either the Shunt body or the tow cord. They did not evaluate the risk of the Shunt coming off the rope without first hitting a knot. 
5. in 2009 Petzl issued guidelines that RATs using the Shunt as a backup device must receive proper training 
6. 2011-2012 discussions and testing show there is no appropriate training to prevent people from grabbing the towing cord on the Shunt. IRATA issued a warning in 2012 that technicians/companies using the Shunt must assess the risk that they might grab the device, and recommended against using it for loads >100kg. 
7. 2014 Petzl recommend Shunt should no longer be used as RA backup device with a towing cord  

So on the one hand it appears Petzl will update guidelines or warnings about using their devices once they have seen enough evidence/testing. Bad news is it could take them a few years to evaluate the evidence and issue the updated guidelines. 

https://www.youtube.com/watch?v=Xh5UJNvrLWM

https://youtube.com/shorts/KM9_co7P92E?feature=share

Here is the proof of concept for the failure method posited in the last video by Yann. 

Sorry to hear about your accident Craig. 

Its interesting to hear you guys go on about the Shunt and how terrible it is. Or how it's outdated and like driving an old car when you could drive something that is state of the art.

If the shunt is such outdated technology tell me about a device that can grab one OR two ropes. One that can be released under load. And one that is not toothed and slips at low loads to dissipate Impact loads on the device and the climber. 

I can wait....

It seems to me that if Craig would have been Soloing on a single Microtraxion and it's cam failed and he decked we wouldn't blame the Micro. We would blame Craig for oy using one device for TRS. One with a known failure mode.

The only thing wrong with the shunt is that it somehow got popular to TRS with ONLY a Shunt. The error is still Craig's error (with all respect to you Craig) because he was trusting his one unique and priceless life to one device connected to one rope by one carabiner. 

P.S.

Laughing at people saying that you only use one harness while tying in. You are actually connected to your harness by your two independent hard points.... 

J W wrote:

“It seems to me that if Craig would have been Soloing on a single Microtraxion and it's cam failed and he decked we wouldn't blame the Micro.”

I suspect we would since, as far as I know, such a thing has never happened. Or has it?

Sorry, I should have been more precise with my words. I meant to say it's cam failed to engage. This is actually a very common problem with TRS on a micro. The cam gets locked open and then doesn't engage and you deck. It's why most people file the tab off the MT if they are going to use them for TRS.

J W wrote:

In other words, the cam never fails to engage. Some users lock it out, either inadvertently during a climb, or they forget to check that it’s engaged at the beginning.

My point was that this is user error. If I understand your earlier comment, you’re saying user error is also the cause of Shunt accidents, and that blaming the Shunt is equivalent to blaming the Micro for a user-caused lockout, which is equally illogical.

Do I have that correct? If so, I agree with you.

I've forgotten to engage the cam once. I'll admit it. But I would always tell people to use two different devices for this and other reasons. Thankfully I was using two devices and I do recheck myself before getting into the crux, where I discovered my mistake and felt horrible for my error. 

More or less. I guess my point is that only using one device is a user error.  Don't blame the device. The true issue is that it got popular to TRS with just a shunt. 

From what I understand the cam can also snag on rope fuzz, stray strand of clothes, grains of sand and random things. They aren't very reliable on their own for TRS. I personally TRS with a Shunt on top extended w a dogbone and held up by a sling around my shoulders. On bottom I use a micro directly off my belay loop. 

Attempting to place blame when an accident happens is unhealthy for the community and misses the point of this thread. But maybe that's all that's left for anyone to try to do here, and I hate seeing my name at the top of the MP forums, so I'm going to go ahead and put this thread to rest. It has served its purpose and then some, so it's time for it to sink slowly out of view.

My goal was only to spread information about the danger of a system that is definitely being used by others in the world. Those who are still using this system may or may not choose to alter their behavior based on my accident, but it would be nice if everyone knew that the shunt can, in fact, detach from a rope with very low force. 

We should all be able to make our choices based on full information. 

Whether a device can detach from a rope under low force is a very important question, for reasons we all understand... if a cam on a single microtraxion failed to engage, I'd be fine because I had a stopper knot right below me. Personally, I would have never used this system if full information about the shunt was available to me (I did search for it and it wasn't out there. Here is one example of search results before my accident)...

... so I think it's good that updated information is now available to anyone who looks. 

(Of course no one should ever place any blame on Andy K -- it's great that he tries to spread info to the community, and he has updated the above statement since my accident. I can't ask any more of a person than that.)

I'm really not trying to be snide, so I don't want what I'm about to say to come off as anything but sincere. But one has to wonder if valuable information is lost when those who have accidents (wisely or unwisely) decide to never post them here. 

Think more about community safety, and less about scoring points. Go easy on your fellow climbers.