When is Redundancy Ridiculous?
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- Опубліковано 24 лис 2024
- Tom Pendley released the 6th edition of the Essential Technical Rescue Field Guide Book and we explore the idea of using only one rigging plate when doing a dual rope / single operator system. Is redundancy ridiculous for such a strong master point?
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How far have you come Ryan. So good to see.
1700 miles closer and I would!
to spell it out, the redundancy in rescue operations is not about increasing strength; it's about decreasing the harm a flaw or error can do. - or in other words, two points of contact is about having to have two failures before you drop the rescuer.
It does go both ways.
I have an anchor made of 50mm (just on 2") 316 Stainless.
I use double chains over it but that steel would need to bend or come through 300mm of concrete.
No need to double up
@@getahanddown if one chain fails from a defect or accident, there is another one. That's the point of the redundancy.
@@kenbrown2808 Exactly. You can't GUARANTEE there isn't a flaw in one of those links, but you can make that one-in-a-million flaw irrelevant by having another section of chain.
One of the considerations that becomes important for rescue - or professionals in general - is exposure. A small chance of disaster encountered many times becomes a not-so-small risk. There are always trade-offs.
@@SnakebitSTI it's the consequences of the failure that are the biggest consideration. if a climber has an equipment failure and has a fall, that is a risk they choose to take. a rescuer does not choose to take the risk of dropping a customer, from a single equipment failure.
Having been a member of our dept’s high angle rescue / USAR team, we always thought that the redundant systems were complicated, time consuming and unnecessary. I’m glad to see that we may very well be moving towards “less is more” in the rescue world.
Thank you so much for bringing in rescue content. Urban rescue where lots of "big" and redundant equipment is just outside in the truck IS VERY DIFFERENT vs Mtn rescue where you have to haul it for miles and only have what you brought with you. Being able to be confident in the lighter stuff and maybe less equip approach is game changing. THANK YOU FOR THIS SERVICE YOU ARE PROVIDING!!!
I think most redundancy is to cover for human error. That monolithic tree really wasn't monolithic. You are not going to put 12KN on a cam. But did you really remove the sand from the wall before you placed it? That sling you just connected. Are you sure that it's even attached? or is it just holding on due to friction.
People make mistakes. Redundancy allows people to get away with making mistakes.
...and to allow for degradation of non-metallic components due to time, abrasion etc.
Finally some brains here. Clearly trying new gear under controled circunstancias is not a correct representation. And as you said this is in great part to prevent human error like basket sling. Looks like they just want to sell more of the rescue guides so people can learn from it (?) Without actual training I guess.
@@Mayorclock3423 These are good questions and comments. Yes, I do want to sell guides but as I said at 11:53, the intent is not to pull this guide out on a rescue, It is meant to be used in a proper training course and then to be able to refer back to the procedures because while these skills are not rocket science, the are very perishable. We did this particular testing because there is so much myth in the rescue world. It's not scientific by any means. We call it quick look testing to gain personal experience and give some confirmation to the theory. In this case, it's fine in my mind to have a single point like a quality rigging plate. It gets two connections. there is no reasonable reason to think a piece of machined aircraft aluminum that is third party tested could fail with the kind of forces that could be generated in rescue systems. Software? I want two. Connectors? I want two. Eyeballs? I want two pairs.
@@DRRRescue The CMC plate has a single point for failure, the large hole.
You could just glue two plates back to back, from two manufacturing runs. I'm not sure how much two plates reduced the carabiner capacity, but I'm speculating not low enough for concern.
@@DevinH-64 So what Im saying is that it is generally accepted in the industry that we grant an exception to the single point rule if the gear: Is made by an ISO 9001 compliant manufacturer with third party testing, has no moving parts and the human is not able to mess it up or influence it. It is not realistically possible to generate the kind of force it would take to fail that piece of machined metal. A human cant make a mistake in its operation causing it to fail. This test was just to show why leaders in the industry are saying that a single piece of equipment like a machined plate, is fine. It does not matter that there is a single hole. you can make the argument the there could be some type of flaw in that aircraft grade aluminum but there is not body count. We aren't failing plates. Well we are but with 100 times more tension than would ever be put on it in any kind or rescue operation. I do appreciate that there is a lot of experience out there but unless people have been closely guarding the incidence of this kind of equipment failing, I would say that it just is not happening and there is no problem with using a single plate.
Personally I always wear two climbing harnesses in case one of them breaks.
That's what we in the USAR business call a Class III harness.
Well, a standard seat harness is usually a set of leg loops that will fully support your weight paired with a belt/waist loop that will also fully support your weight and both connected with a belay loop. So yeah it kind already is.
Belay loop is a single point
@@CragDawgs - oops, time to double up.. (NB, the belay loop is tested, certified, and is only designed for the single user weight, probably super good enough (paracord can hold static body weight- spectra kite string, a lot more)...
@@kadmow too bad harness is not made out of paracord then :(
I'm in love with the technical rescue daddy, so factual 🥴
I’d trust him with my life just by looking at that glorious mustache
Tom is a legend! Thanks for having him on the show. I've already sent this episode to all of the members of my technical Rescue team.
I've been working in rope access for 15 years now. We use redaduncy everywhere because of human errors. When choosing your anchors you can make a mistake without knowing it. It's the same for climbing or caving, that's not because there's 22kn engraved on an anchor that you can rely on it at 100%. It's always possible that there are some invisible issues with the rock (cracks) or the glue (dust in the hole when gluing)
Yeah, but this double stacking rigging plates thing doesn't stop any of those mistakes and is a bit silly.
Yeah a lot of people seem to have missed the point here. Redundancy is a good thing. But by having two of everything, or super highly rated devices, you aren’t actually always adding redundancy. You’ve got to be thinking about modes of failure and redoubling the strongest link in a system isn’t making you any safer.
In fact at a certain point, the added complexity makes human errors, or complacency more likely.
You can spend more time and money and training and weight to eliminate a tiny risk, even if you haven’t overlooked any other larger risks that require your attention, and I would still say that there should be a limit to redundancy.
Like if there exists some freak one-in-a-billion risk that can be avoided by making those plates redundant, is it worth it? Or are you more likely to trip and fall to your death, or get struck by lightning while hanging from it, or die by cardiac arrest while on the end of the line?
At a certain point, the risk is irrelevant.
Thanks for moving to the tech rescue world....looking forward to more discussions on how emergency personnel setup their systems and what safety factors we are accepting
Awesome video!
Very helpful.
It was interesting to find that 2 plates make the Carabiners weaker.
I'm loving your collaborations with other professionals
Redundancy is critical with industrial rescue. Most rescue team members are plant employees, who typically do not get the necessary repetition to be proficient with rigging, knots, etc. CMC has done a great job engineering useful equipment that minimizes the likelihood of "operator error". Their video library has been a huge help understanding how to safely use their equipment. Great products!
Sounds to me like it mostly makes things more complex and introduces more failure points. When there are a lot of carabiners, slings etc. it often becomes impossible to see the actual weak link. For example you might overlook that you are using a sling as master point in a way that a single cut strand could lead to failure of the whole system (and you might overlook that said sling is rubbing over a sharp edge). Or you might be building your anchor using several bolts or cams and overlook that they all rely on a single boulder or rock flake not coming loose.
@@Mike-oz4cv Industrial rescue can be more complicated. Particularly, anchorage points. OSHA requires engineering rated 5k lbs( per person supported) anchor points. Most plant employees without proper training would see no problem securing to a handrail. I try to keep the equipment simple, anchor strap, carabineer, clutch, capto, Tripod. That'll be sufficient in 90% of our scenarios.
Thank you for doing more rescue and professional stuff. I also love that you’re making cmc gear available. Sick colab
I saw a comment on a heli rescue video where they admonished the guy for only using one bear paw. I was thinking it would be cool to seee you break test it and my god here it is.
Coming from technical rescue side, in general we would backup software but not hardware
I’m a duel cert rope access tech IRATA/SPRAT. SPRAT says one rigging plate is enough. IRATA says you have to double them.
Technically irata doesnt say you need 2 rigging plates, just 2 independent points/redundancy. 1 rigging plate with a nylon sling back up achieves the same thing without risking carabiner damage.
I get iratas point of always needing redundancy but then is completely inconsistent by allowing both the mainline and backup to be attached to the same d-ring on the harness (which is much weaker than a rigging plate).
@@adamwood9144Not anymore. Now the 2 points must be independent, sternal and ventral D rings.
@@toolsreviewsandmore5326 can you link to the written policy/procedure so I can read it?
I remember asking if you could do an episode of this back in October because IRATA/ICOP states using rig plates must use 2. Thanks for making this episode
I was recently talking about this with some IRATA people, including an instructor. They use doubled plates because the IoC requires everything to be doubled, but mentioned they use a single plate for anything non IRATA. Richard Delaney, the one mentioned in the video, has an article where he describes why he's happy with a single plate too. Super bomber enough
What if there's an invisible crack or some other manufacturing defect in the plate? What if it somehow gets loaded weirdly?
I'm sure it's pretty much entirely safe to use just one, but if adding another makes it just that slight bit more bomber, why not?
@@nerfzinet microfractures aren't an issue with modern equipment, any real issues will come from heavily overloading it (which you can control yourself) or visible fractures. Adding a second plate doesn't make it stronger, but the loading on the carabiner will actually make it weaker when adding a second plate
@@jetseverschuren someone just texted me about microfractures, I don't know enough about metallurgy to speak to that but as a small sample, Ryan and I broke a 30+ year old plate last year with just one connector on each side. It was 43 kN and that plate was so dinged up and battle scarred from 30 years of use. I speculate that it would've been much higher number if we had configured it the same with two connectors on each side. Video here. ua-cam.com/video/nHfUiQf53Xs/v-deo.htmlsi=X8ATTlwzXU71pxWt
@@DRRRescue I'm no metallurgy specialist either, but as far as I'm aware, microfractures (at least from impacts) has been pretty much debunked for modern equipment that's properly heat treated. There are a few documented cases of people using aluminum carabiners for slacklining, where the high amount of cycles caused some fatigue in the carabiners, eventually leading to failure in some other situation (I though climbing) at absurdly low forces. So as long as you know the history of your equipment, there shouldn't be any issues
Well done gents. Thanks for all you do for our community.
Great testing. The 2nd set up is how I rig but have been told by IRATA that I must back up the plate!! IRATA need to get a grip.
If you were to connect 2 sets of ropes (mainline and back up) would you use one 40kn carabiner or two? As far as the marked ratings go it’s the same thing. Personally I use a 1 rigging plate with nylon sling/s as a back up to the plate, no strange loading on the biners that way.
I have seen a few people back them up with a sling but if you're generating enough force to break the rigging plate, the nylon sling doesn't stand a chance so always seemed a pointless endeavour.
@@pl7577 it’s not about the potential force that it would take to break a perfectly sound rigging plate, its that the rigging plate could have a manufacturing defect or undetected damage causing it to fail at a much lower force. This is the point of redundancy, short of cutting/melting a rope or nylon sling no one object in any system should be able to fail under the force you are putting on it unless you are a total fool. It’s also worth noting that the force on a piece of equipment that fails is not necessarily the same as the force that the back up system will see, depends on the situation, for example if you took a large enough dynamic fall onto a piece of equipment the energy absorbed in the failure may well result in a reduced force to the back up system.
Folks get too hung up on rigging plates, there is no difference in essence between a 40kn rigging plate, carabiner or metal sling. I imagine most folks would think it strange to attach a double rope system to a single metal sling and carabiner.
Good to see you Tom. This is so much better than breaking stuff in the parking lot with a 20:1. Never trim those eyebrows!
Is the guide available in Europe? If not physically maybe there is an ebook/pdf version of it available for purchase
It’s a tiny weatherproof book, fits in my chest pocket easily. First thing I grab when I throw my gear on. Well worth ordering from the states if required. Likely available local to you.
Pretty sure it was Kirk Mauthner of Basecamp Innovations, not Richard Delaney, who developed and advocated for the dual capability two tensioned rope system. He presented at ITRS on the topic in 2014 and 2016.
For the first test, try repeating it without the upper carabiners. The narrow curve of the carabiner was point loading the master point, hence the deformation at the points where the carbines were contacting it. Using soft shackles or slings, that would conform to the curve of the master point, would remove the point loading.
Its an endless and often ridiculous debate.
You can lift people with a single crane. It has one rope. One winch. One boom. You get the idea.
Over the weekend i snapped several ropes under normal load, due to age.
A number of knotted dyneema lines amd blew out a couple of incorrectly threaded blocks.
I watched a neighbouring crew start to hoist someone up a mast with backup line over a wire rope and a number of edges. Also not maintaining a maximum static fall for the backup. And i did intervene to point out their more critical hazards.
Most folk.just don't know and then assume that two of everything makes it safe. As for the T.A.. they should know, but just assume that two of everything makes it safe and absolves them of any liability either way.
Who remembers when you were allowed to tie your own knots ?
The redundancy in occupational settings and the hugely different safety standard in general is to account for user error. When you're a recreational climber, you can decide to just not do it if you're not felling 100%, if you've got a bad gut feeling, whatever. In an occupational setting, that is often not as viable of an option as it should be. Maybe you're an arena/event rigger walking on the beams at the end of your fifth 12 hour day in a row. Maybe you're a rescue technician who was woken up by the notification in the middle of the night and now needs to rescue someone, mere minutes after being ripped out of your sleep. Maybe you're a rope access technician maintaining a building, and even though you're tired and just not feeling that good, you power through because it's your job. In all of these four situations, the likelihood of user error is dramatically increased. You'd be surprised by how much tiredness can impede on your brain's ability to get even the simplest things right, and that is a big problem when your safety depends on whether you tied a knot correctly or incorrectly.
Another reason for the high safety standard is that it dictates what a boss can demand of a worker. If a recreational climber finds that something is unsafe, they can just not do it and that's it. If an occupational climber finds something is unsafe, there needs to be some sort of technical standard that determines what is and isn't safe so that it can be determined whether the climber is justified in refusing to do the work or not. And logically, this technical standard needs to have a high safety level so that workers can't be forced to take unnecessary risks.
The third reason for the high safety standard is to account for unrelated health problems you could be having while in your harness. If you're climbing recreationally and you have a heart attack while doing so, it's your responsibility and your problem. In the occupational setting, the employer is responsible for the safety of the employees, so if they have a heart attack while harnessed, the employer has to make sure they can be rescued and receive the necessary medical care. It's about making sure that a bad time doesn't become even worse when you're harnessed. I'm saying harnessed because this is especially visible in the standards for fall protection: in my country at least, a railing needs to have a 10cm footboard, a pipe at 50cm and a pipe at 100cm (or 110cm depending on the height) to be considered safe. So if the railing protecting you doesn't have the pipe at 50cm or the footboard, you need to be harnessed, even though in normal situations, the railing still protects you from falling. But if you stumble and fall for some reason, like because of a sudden aneurysm or whatever, you can fall because then, the railing really needs all of those three components to keep you safe, so that is why you need to be harnessed in that situation.
With redundant systems, you've always gotta weigh the value of redundancy versus just having twice as big a system. This is why for example we do not use redundant wing spars in an airliner but we do use redundant control connections.
Not a climber, never will be, I've been enjoying your videos. I have ADD (I think) or at the bare minimum am too lazy to pay attention usually, but I've been able to enjoy this content all the way through even on long ass videos. You are providing great information for anybody who wants to at least learn what is important to think about, especially considering the consequences for not knowing what you don't know could mean that your rack of nuts gets damaged and stuff. The historical stuff will be precious one day, interview more of the old dogs while you can!
Really awesome you are carrying rescue gear! Good on You!
Wish I lived near that area and could geek out on that job opening. Since not, will support by buying through your online store when I need gear.
Once thing that wasn't discussed (unless I missed it) as the fail tests continued, is the wear stresses of each attempt, weakening the parts closer to, or even below, their original 2-1 or 5-1 safety factor thresholds. Not so...? Just a point to remember in the field as your gear gets put into successive service.
I enjoy this so much! Amazing content, best wishes to you and your future projects! 🌻
Thanks HowNOT2, helps a lot!
For a while now, redundancy is more about eliminating human error than it is mitigating equipment failure. If you are in a rope rescue scenario then you should be using equipment that is more than strong enough. Thats said, there is no reason for multiple plates. If a human doesn't have to operate it (open, lock, or tie), then you probably don't need two.
4:22
I'm an IRATA technician since 2004.Things changed a lot and that is mostly to prevent human error.
Also they change after analysing accidents and incidents and find out what went wrong. If it was human error,change the method the task is performed, it if was the gear,improve it or remove it from use.
ISO 9001 Compliance doesn't actually mean anywhere near as much as you'd believe, it entirely comes down to the company they contract to produce it.
THAT SAID, it's a single part, tollerances mean basically nothing (With a exception of thickness but I can't imagine they'd try and get away with anything so undersized that it would compromise the strength.) so yea, ISO 9001 compliance means they have to buy traceable materials and that's enough in this case.
I work at a ISO 9001 and 14001 certified company. I've participated in many audits by customers and ISO. In my opinion it basically means a company has their stuff together. The quality assurance dept has the ducks in a row, and documentation is on point. There's a ton that goes into getting these certifications so it means the company is actually trying and cares about their product.
How are soft shackles so OP? 😆 Genuinely looks like some random thing someone made from hardware store materials, which I guess isn't far off, but it still amazes me.
They are made from dyneema, like the slings, just a lot thicker.
I imagine that the PAW M brakes at twice the MBS because the MBS maybe it's calculated using just one "carabiner" in each side of the plate. but the test that they did here it's more realistic, because you don't use a rigging plate to use just one hole.
an interesting test would be having just one point in one side and 2 or more in the other side of the plate
There are two ways to get redundancy: Put in two, or overbuild. Climbing mostly uses the latter.
Strangely enough, twin engine general aviation aircraft weren’t safer than singles. Adding complexity isn’t necessarily better. Sometimes it just adds failure points
Aluminium has fatigue. And it progresses unlimitedly until it breaks. Unlike steel that always keeps some strength after fatigue. So steel is quiet unique construction material in this regard.
Great video! At 5:50 you mention that Richard Delaney proved the benefits of twin tensioned systems. I believe that was Kirk Mauthner, not Delaney. Here is Kirk's original video that shook the rescue community, and was the first real proof that "dedicated main, dedicated backup" was built on a false assumption. In his ICAR talk he says he was trying to show the benefits of an untensioned belay, but his experiment to his surprise showed the opposite. ua-cam.com/video/-43yf8SDs4M/v-deo.html
Yes you are correct. On the day of, it's kind of stressful shooting totally off the cuff and I missed that point. I noticed yesterday when I saw the draft but wrongly figured it would be hard to fix and should have said something. Truly we stand on the excellent work of really brilliant pioneers in this field Like Kirk Mauthner and Richard Delaney and many others. So my apologies and thank you for setting the record straight because those two guys really have done brilliant work. I want to point out that I read in one of Kirks test reports that the Canadian group agrees that a single anchor plate is fine as a master point. I just cant remember which one I read it in.
Worked in manufacturing hard goods at Conterra for a short bit. Good people right up the road from you in Bellingham. Rick would probably be psyched to sync up with you.
When you go climbing whether it be a rock face or felling a tree, sure you have the rigging you need but if the situation surprises you and you don't have the RIGHT gear it's always an option to go home or back to the shop and come back with what you need. Or pick a different route to climb today. Or talk with the homeowner and explain you want to safely give them the best service with zero risk to their property.
In rescue the victim picks when and where they need to be rescued. Going home without them isn't on the menu.
If it's pretty easy, and doesn't make people screw up because they get confused, go for it. For me, the redundancy because a sling might be cut by rockfall... is interesting. I've tracked down the one documented case, and have other... thoughts.
I've been hoping for more rescue content.
If I did my maths correctly, two of those gold plates could be used to lift a British Strykr IFV at 19tons
They are so impressively strong!!
Would love to see you check out the Sick Sequence bouldering pad.
I don't believe it's a safe idea as air follows fluid dynamics it and is highly compressible I believe the danger of bottoming out the mat especially if you don't fall flat/well distributed bodyweight is really high.
Could we not lower the breaking strength of that plate if we somehow manage to hinge and bend it? Not a straight pull but some kind of rock formation that will bend the plate.
Okay Ryan I ordered one. I love buying stuff from your site, but since I don’t have a redundant bank account, I just can’t buy all the stuff I love, lol. So, please feel free to throw in some more stickers or a spare Z2R if you have one laying around. Thanks…
Great video!! What I’m most curious about is when using plates in highline/ rope swing rigging is there any cause for concern with fatigue of the aluminum? Obviously super strong on one single pull but what happens after it’s been cyclically loaded?
Lovre your content, have you thought about doing a test on Cobra buckles?
I thought for a minute that you were using brass knuckles as climbing gear...
Spotted this item in the thumbnail, YT right sidebar.
Surprised only _two_ of us had the same thought.
Question, the way the basket hitched dyneema is connected in the video, could you do that for rock climbing anchors using locking carabiners on each end? To me, it looked redundant and way stronger than using 1 dyneema sling with a BFK or overhand and since dyneema tends to slip when broken (past videos show the knot coming undone in away) it seems safer than hoping a knot holds when broken. I understand we are talking about forces that most likely wont ever happen, just curious if this is a "safer" solution than one dyneema.
The best part about redundancy is that it forces the person who sets it up to look at the system twice.
Actually, in Rescue, the requirement is that you must always ask your contraption to be inspected and accepted by a second pair of human eyeballs.
Really appreciate the videos! Keep it up
Have you done any picket testing before for rope anchors in the past? There's alot of variations of setups and angled picket use vs straight.
I wear two harnesses when climbing. It is the only safe way
If you are going to use two rigging plates, you should use two different plates, not two of the same. You aren't doubling them to make it stronger. You are doubling them in case they are faulty and don't get close to their rating or fail in some other way. If you have two of the same, especially from the same batch, they could both be faulty. Perhaps the supply of metal they had that day was faulty. Or the annealing machine was set to the wrong temperature. Or one of the plates is actually a cheap knock-off. Having two of the same doesn't provide much extra protection.
When the 69kn was revealed I made what I can only describe as my best impression of Michael Jackson's "Oooh!" from the beginning of "Don't Stop 'Til You Get Enough"
"Redundancy" is a lot less specific in climbing, and for consideration: One rope is actually made of hundreds of nylon filaments; it is internally redundant, to the degree that ends up being pretty foolproof in normal usage. Protection on leads is redundant, as long as one remaining piece keeps the person off the ground/landing. One 22kN locking biner is usually considered as bombproof as his master plates, for normal climbing use, but in practice even clipping any secondary line to another anchor point feels a wee bit safer - and Todd Skinner and Paul Piana's famous near-catastrophe at the top of the Salathe Wall was averted by one last piece, as I recall, while the rest of their system was sheared off by the massive boulder.
Can you, (or have you?), pull test(ed) rigging plates and carabiners that have been arc striked by a welder?
Hey Ryan! Is the rescue book also available digitally?
Was the force on the plate rated for only connecting a single point on each side? So connecting 2 points either side is effectively 2 x 45kn ~ 90kn ?
It's MBS; MINIMUM breaking strength. Its not actually what force it breaks at, just the minimum force it might break. stronger is fine, just not weaker.
I assume its 45kn for a connection from any hole to any other hole.
Its definitely 45kn on a single ring.
@@merlin_V2 Saying "definitely" makes a mockery of HowNOT2's entire existence. Their's a "you never know until you break it" mind set. 😆
The emphasis should have been on a single ring. Because the weakest link should be the minimum breaking strength.
@@merlin_V2 Well, thats not what they were testhing, tho.
never understood why they dont use WLL, working load limit, which always have a factor 2 or 3 safety margin , like anything else for rigging
Because rope rescue requires 15:1. Rigging world isn't lifting people, they have lower requirements.
@@thekid760 that may be true for your accreditation but certainly isn’t true for all. Some industrial rescue procedures allow for rigging to hand rails we could be incredibly strong but only have to technically conform to an outward force equivelant to the weight of an average person. Rope access, IRATA goes off 15kn (which technically is 15x a 100kg person) but allows 2 people on a system in a rescue. The 15kn is actually based of (low likelihood) max allowable impact force of 6kn with a 2.5 factor of safety
@@adamwood9144 correct, I should've clarified. NFPA 1983 requires a 15:1 for general use in emergency services.
I would go with a plate with a hole for each anchor point. Since if the perimeter of the hole fails, only 1 hole fails, not the whole master point. Making the plate inherently redundant.
Ie, the example at 2:10 isn't actually redundant since if the hole on the rigging plate fails at the anchor side, then it won't be securely attached to any anchor. This is a single point of failure. Even if a rigging plate in good condition can handle forces far beyond what is needed for the application, that still isn't redundant but rather an acceptance of marginal risk.
Some might argue that a single rigging plate can't be redundant, this is a bit of a myth that one supposedly needs two separate components to achieve redundancy. It is however a good rule of thumb.
Redundancy is only about handling one (or more) failures of individual aspects making up a larger system without the larger system itself failing. If the larger system has any choke-point where a singular failure makes the system collapse, then the system itself isn't technically redundant, if one wants to be super pedantic...
But in practice, reaching actual redundancy in any system is more theoretical debate than anything.
In reality one will have to brush some of these choke-points away as acceptable risk if it is infeasible and/or needlessly complex to make that aspect redundant.
The lack of redundancy showcased at 2:10 is fairly trivially amended by using a differently designed rigging plate with two separate holes for the anchor points. Preferably separated a bit such that a brake in one doesn't meaningfully compromise the other. This amendment isn't infeasible nor needlessly complex, making this single point of failure fairly unacceptable if one desires redundancy.
However, with two separate anchor holes one will have uneven tension on the ropes if an anchor point fails, since the rigging plate will rotate. But the main operator is able to equalize the tension on these ropes again in fairly short order, nor does it matter that one ropes is a few inches longer than the other. I rather much accept this than a free fall, any day of the week.
In the end.
Super good enough is however still a good way to look at it. Like I won't say that the rigging plate is garbage. But in a redundant system, one would prefer the bar for introducing acceptable risk to be higher when the solution to the single failure point is as simple as this.
Those blocks are great for arborists and as a FF, yes we want redundancy. It is too much when the time it takes does not improve your survival chances.
Looks kind of weak if you are used to industrial cranes. The standard is totally different there. If something is rated for lets say 10 tons, you can lift 10 ton all day every day for years and still be good. The actual breaking point is several times higher than the working load to allow for many things to go wrong before you have an accident.
For example, my 4 ton overhead crane has 4 9mm steel cables which each would break at a minimum of 5.2 ton so actual failure would occur at like 21 tons. Everything is overbuilt. So if this was for an industrial job, this plate rated for 4 tons would be made out of like 20mm thick steel and would weigh like 5 kg.
The differences maybe smaller than they look. Climbing gear is rated by the break point, rather than the safe working load. Ryan has many videos on the actual loads at play.
That's Bc nobody is halting 1 ton humans everyday lol
Im interested in that assender device you sell the red one.much smaller and lighter then my grcs plus can use it solo..
The problem is anomalies in the manufacturing process, it's russian roulette, and for lighterweight items, fatigue.
I suppose if you don't trust Petzl's manufacturing and quality control, you could make them yourself. Personally, I trust them more than myself though.
@soffes I mean, people have died from their products failing before... no manufacturing process is perfect, or perfectly consistent. No one has ever died with a redundant system failing though, so.... good for you?
@@soffes not sure if the many recalls they've had over the years is due to high quality control or low quality control... but I agree about the trust side of things.
This is exactly what I scrolled through the comments to find.
If it’s built properly you shouldn’t have a problem, but one flaw in the material could compromise the part. If it were me, I’d go with stacked plates (preferably from different manufacturing runs) because you dramatically reduce the chances of two failing at the same time.
You also need to consider that even with redundancy the failure can have side effects. If you have one failure, the shock can put addition stress on the other. With the safety margins at play here that shouldn’t be an issue if the second one is sound, but it needs to be considered in the design. With stacked plates, the way slack is taken up between the plates wouldn’t be likely to do that.
@@rainmannoodles I get it, this is high consequence stuff, so redundancy feels good but, I've been doing this for 30+ years with many many evolutions. I have never seen a piece of hardware or software fail in the types of tension with two person loads that we typically do. Yes, we have damaged equipment and yes we have had failures from side load of carabiners and yes, we've had abrasion incidents on rope and other software but never a failure in tension. Does it happen? Probably but I would guess the incidence is so small that it is statistically insignificant, just saying.
Simple question - what is the alloy these plates are made of? 7075 or similar, or something new?
Cool. Like that guy
@hownot2 - ongoing debate on redundancy in anchors. People travel to Spain and see single fixed biner sport anchors (ie 2 bolts connecting chain terminating in a single nonlocking steel biner). Sometimes these are captive biners, sometimes not. They then think it's a-ok to do this back in N America.
Would be good to test what scenarios can create failure in this this single biner anchor system.
In my mind it only cost a few $ more to add a second biner to your open anchor system - just in case something like a big swing out (ie cleaning) can introduce failure. I mean - what could possibly wrong lowering off a single biner right? :)
Lastly - some redundant systems also have problems - like the recent mussy hook incident where the climber died. I did a route in Nevada recently that had opposing mussys side by side - and the rope pinched between the hooks to a point we could not pull. Checking online - many people had issues with the same route (Mesquiter in Lime Kiln). Would be great to have a video on anchors that seem good but are problematic for less obvious reasons.
If you make it out of forged Titanium, how much stronger would it be?
this was awsome!!!
Safty or rescue equipment has a minimum safety factor of 2 engineered into the ratings. This is why your test failure is about double the rating.
Your thinking of lifting/rigging gear, this is marked as a Minimum Breaking Strength. If it fails at higher than that it’s usually due to batch testing where the lowest test figure is what’s used for the whole batch so others in the same batch could be stronger.
It failed at double the MBS because they load shared two 45kn holes, no surprise there
fantastic video
In Europe we were using typically double ropes so no even ropes are doubled
Im still impressed that the HN2 soft shackle can hold 96kn!!
Need to have a digital caliper on hand to know if the plate has deformed
Please test T rated rescue gears from Petzl, CMC.
Can I use a Petzl rigging plate with steel carabiners?
Love that guy!
Is that the black diamond 10mm dynex 60cm"?
I used to be a rigger. Anything that is designed to hold a human, the working load capacity is half of the breaking strength
In the cost cutting shareholder profit 21st century you still trust that everything is manufactured correctly?
With someone else's life....
I love space sci-fi and there's an astrophysics term for when you're travelling at stupidly fast speeds..... like close to or farster than the speed of light.... and something goes wrong with your ship ---- spaghettification...... emagine your feet moving faster then your head and you should understand the term 😂 I bring this up as I'm pretty sure that spaghettification would be your reality if you suddenly find yourself in a position where you just put 96kn through you and your system!!! 😅
that petzl master is verry impresive
During the testing: "Oh, THAT is not the same shape!" heh
Plates are good!
96?!? That's insane!!! Could tow a trailer with that thing. My god
Could tow multiple trailers with it. That's almost 10 tons. You'd rip out the trailer hitch before it breaks. Not that your car would have enough power to break it anyway.
Pull a trailer? They could have hung my 34 foot class a motorhome from that thing.
I love CMC!
Every manufactured device in rescue gear has a factor of safety engineered in. Typically two to one.
Super good enough! 👌
You have to put a safety factor into it
Why not use a Snatch Block??
If you can Lift 2 Hummers before breaking... I would say it is good enough for lifting people 😅
Can you order an E-book? Or do you ship to Poland?
We can. Just email us at contact@hownot2.com and we can make a draft order for you. 🙏
If it takes 15 min to set up your confine space rescue the person is likely already dead. Confine space
should always be pre planned and pre rigged. I've always found rigging plates for dual descenders to be a waste of time and head height and you can generally get better results without them.
Outside of trad placements and bolts-of-unknown-origin, i see reduncancy more about the humans setting it up. 1/1,000 times a human will make a mistake, so redunancy makes failure 1/1,000,000
Tom looks familiar, I think he may have taught his class in Little Rock. #LRFD