When to use screamers

419 wrote: He explains his gear in the video including sharp thingy's, slinging icicles and clippy things. Focus on the work house of the rack.

haha Will totally called that coming off. Not suprising!

What's all this talk about ice for?

My entire sport rack is made up of screamers.

Great feedback. After going over all the info, my preference will be for Zippers on the bottom and more slings up top. And now I finally have it into my head which is a positive and negative placement. Thank you Ben.
And as far as spending the money on screamers - My friend was belaying a guy at Lincoln last week who took a lead fall, first screw came out, screamer deployed and he didn't hit the deck. He's bruised, but walking, so 20 bucks is cheap!

I will screamer the top anchor piece as the first piece of pro if it looks like the leader will factor-two. A partner blew at screamer 9/10ths (I had a single wrap of athletic tape holding the ears from flopping which is coincidentally where the ripping stopped) from a 35ft fall onto the anchor.
I caught him and got yanked up,then the screamer activated which took his weight and wailed in my ear. When his weight momentarily came off me while the screamer blew l thought he had come off altogether! It was, however, a much beneficial use of a screamer.

I'm glad someone finally posted a freakin' picture. I've placed three screws in my entire life and even I know what angle to put them in. Can't believe it took that long for everyone to agree that they all know as well.

Screamers are superb and should be on everyones trad rack. I carry two year round to use on marginal or blind placements. With a fall factor of 1 the forces on an anchor are about 11Kn, but by using a screamer they fall by over half to 5Kn. That could save your life. Whenever the Ice is just a bit marginal I use one, I use them on old pegs, or rusty bolts or anything else that just makes me wonder - "how good is that really?"
From Yates:
yatesgear.com/climbing/scre…

Really they dont weigh a lot, they are not that pricey and to be honest a couple go a long long way.

funkyicemonkey wrote:With a fall factor of 1 the forces on an anchor are about 11Kn, but by using a screamer they fall by over half to 5Kn.

This is so incorrect it's amazing you haven't killed yourself yet. Stop giving out advice when you don't know what he hell you're talking about. The force of a factor one fall "could" be 11kn depending on the weight of the climber, the type of rope used, type of fall, etc. etc. etc. A screamer DOES NOT determine the final KN force of the fall nor does it limit it to 5KN. Sheesh.

BTW...those numbers in that link you posted have been shown to be wrong by several people who have performed exhaustive testing. Google is your friend.

i scream when i fall ... im a screamer =(

Sally G. wrote: My friend was belaying a guy at Lincoln last week who took a lead fall, first screw came out, screamer deployed and he didn't hit the deck. He's bruised, but walking, so 20 bucks is cheap!

Screamers are good, but it's a bad call, IMHO, putting faith in them and placing shitty screws. I'm not saying I'm not guilty of this - but when I did have a shitty placement I was well within my limits. Learn and practice the art of downclimbing if you can't find a good screw placement or if it's way over your head. Perhaps if the guy didn't waste his energy to place a shitty screw he could have either climbed higher to get a better placement or down climbed back to the ground.

doligo wrote: Screamers are good, but it's a bad call, IMHO, putting faith in them and placing shitty screws. I'm not saying I'm not guilty of this - but when I did have a shitty placement I was well within my limits. Learn and practice the art of downclimbing if you can't find a good screw placement or if it's way over your head. Perhaps if the guy didn't waste his energy to place a shitty screw he could have either climbed higher to get a better placement or down climbed back to the ground.

All good in theory.

Unless and until somebody can provide credible tests, I think screamers are an exercise in wishful thinking. To the extent that this is true, Dolgio (and Will Gadd's) position that they are just lipstick on an inadequate protection pig seem like the only rational approach.

The various testimonials are worthless, since they do not involve repeating the same situation without the screamer to evaluate what effect the screamer did or did not have. If screamers make you feel better about your pro, go ahead and use 'em, but understand that there is no good experimental evidence for their effectiveness on anything except very short falls, and elementary physics considerations guarantee that they cannot reduce the loads significantly when long falls are involved.

The most interesting experimental results about screamers in the the climbing context are the drop tests done by the CAI ( caimateriali.org/homepage.html , but I can't find the article at this point) [Edit: the article is at caimateriali.org/index.php?…], tests that suggest that screamers are not effective in reducing peak loads when their full deployment is not enough by itself to absorb all fall energy. In other words, if the screamer fully deploys and then the rope has to stretch further to stop the fall, there appears to be little benefit to having had the screamer present at all. As far as I know, the CAI tests are the only ones that used a real belayer rather than just tying off the rope to an anchor and so providing a totally static belay.

Beware of the pseudo-physics arguments in places like the Yates site, which, after admitting that there does not seem to be any good explanation for so-called "observations" about screamer performance, advance the idea that screamers work by making the fall arrest take more time. The fall isn't going to stop until all of its potential energy has been absorbed. Energy is the area under the graph of tension vs. stretch, not tension vs. time (impulse). So, for example, it takes more time to stop a long factor-1 fall than it does to stop a short factor-1 fall, but the peak loads are the same. Time isn't the issue, except in the secondary sense that it takes longer for more stretching to happen.

In the case of long falls, it is obvious without experiment that screamers will have a negligible effect, because the fraction of the fall's potential energy the screamer can absorb is small and so the majority of energy absorbtion still falls to the rope. But the CAI tests suggest that even in more moderate falls the screamer is not much help. The most optimistic perspective on screamers says that they will reduce the load on the anchor to the level obtained by a fall that is 3 feet shorter. This is good news for, say, a five foot fall, but insignificant for a 20 foot fall (waist 10 feet above the pro), and ignores the CAI testing, with real belayers, that suggests that screamers might, in low-friction conditions, short-circuit load-reducing slippage in the belay device and so end up doing nothing or even increasing peak load.

The BD tests cited upthread seem to me to confirm this, as well as reveal some fundamental misunderstandings on the part of the BD engineers involved. Gauging the seriousness of a fall by using the fall factor is appropriate when the mode of energy absorbtion is the rope, which can be treated, to a first approximation, as an elastic medium that is scalable (more or less rope can be involved in the fall arrest). A screamer is neither elastic nor scalable. It is capable of absorbing a fixed amount of fall energy, basically its activation load times the length of the extended screamer. If this fixed amount of energy is a significant fraction of the total fall energy, the screamer will be effective, otherwise not, and so the only thing that matters for screamer effectiveness is the fall height, not the fall factor. The BD tests are almost a joke, because in order to "detect" screamer effectiveness they have to use falls so short you could basically grab the pro. Those tests tell you nothing about the performance of screamers in any situation beyond the shortest aid fall, and in particular provide no evidence about what would happen for longer falls of the same fall factor.

From Jim Titt:

"With screamers there are three camps amongst the manufacturers. There are those who promote them as the answer to everything and make claims which even the most deluded find a bit dubious. Then there are those who hum and haw around the benefits with plenty of "cans" and "mays" (the Petzl website is a masterpiece for this). Then there are the ones who never got them to work, got pissed off with the whole business and don´t make them, who are incidentally in the majority.

From my chats with the technicians in industry the most positive thing you will hear is "they might help" which is not exactly a positive endorsement. Some, who have spent a long time trying different sewing patterns and cold days on the test rigs are less charitable.

Since there is no UIAA/CE test for these things all we can fall back on is our intuition, a bit of private testing, some back of the envelope calculations, information leakage from the industry and the Italian testing which was about as complete and credible as we can hope for at this stage. From all these the manufacturers claims don´t come out well and some braver souls such as myself would be prepared to brand them as hype or worse to sell an effectively worthless product.

Since the issue has been open for many years and no manufacturer has ever published any verified test results from an independent test laboratory to clearly establish where the undeniable benefits of screamers stop and the undeniable negative aspects start, then I feel the public can say or do what they think and so they should.

Time perhaps for one of the manufacturers to step up to the plate?"

I know that this is a very sciency and pompous forum and my question is simple but... I had a buddy fall on a screamer which only partially deployed (about half of the threads popped). In this instance, didnt the screamer absorb enough energy to make it so that the remaining threads did not receive enough force to pop? If this is the case, didnt that absorbtion of energy create less load on the piece of pro?

clay meier wrote:I know that this is a very sciency and pompous forum and my question is simple but... I had a buddy fall on a screamer which only partially deployed (about half of the threads popped). In this instance, didnt the screamer absorb enough energy to make it so that the remaining threads did not receive enough force to pop? If this is the case, didnt that absorbtion of energy create less load on the piece of pro?

that has been my reasoning on the topic. i have partially deployed screamers on three different falls, one being on a pin in a flake. thats the only data i need.

clay meier wrote:I know that this is a very sciency and pompous forum and my question is simple but... I had a buddy fall on a screamer which only partially deployed (about half of the threads popped). In this instance, didnt the screamer absorb enough energy to make it so that the remaining threads did not receive enough force to pop? If this is the case, didnt that absorbtion of energy create less load on the piece of pro?

yes, but probably not significantly less load. Like Rgold mentioned, it all has to do with the length of the fall, but if it was a normal lead fall (i.e. more than a couple of feet) then it was probably not much of a reduction. If the screamer partially deployed than we know that the force on the piece of pro didn't exceed the screamer's activation force. I don't know what screamers activate at these days (and don't really care to look), but let's say that they activate at 5 kN, the partially deployed screamer probably reduced the peak force from something like 5.1 kN down to 5.0 kN.

clay meier wrote:I know that this is a very sciency and pompous forum and my question is simple but... I had a buddy fall on a screamer which only partially deployed (about half of the threads popped). In this instance, didnt the screamer absorb enough energy to make it so that the remaining threads did not receive enough force to pop? If this is the case, didnt that absorbtion of energy create less load on the piece of pro?

Yes. In that case it limited the load transferred to the piece to the activation force of the screamer. Think of it as a load limiter. So long as it has stitches left to tear it transmits a maximum of ~500lbs force. Once fully deployed, if there is still significant energy from the falling climber, the load on the protection will likely increase. The biggest thing i've taken from reading this is we don't have enough data to really understand what happens in the system once the screamer is fully deployed. The best estimate is it effectively "shortens" the fall by about 3'.

the best advice is just dont waste time placing dubious gear. when in doubt run it out.

To all of those involved in this inane rambling thread...
youtube.com/watch?v=zTFwAxf…

clay meier wrote:I know that this is a very sciency and pompous forum and my question is simple but... I had a buddy fall on a screamer which only partially deployed (about half of the threads popped). In this instance, didnt the screamer absorb enough energy to make it so that the remaining threads did not receive enough force to pop? If this is the case, didnt that absorbtion of energy create less load on the piece of pro?

Since the screamer didn't fully deploy, we know that it wasn't called on to absorb much fall energy. If the screamer absorbed all the fall energy, then the fall would have to have been short, and in that case the load to the anchor would probably have been reduced significantly, as in the BD tests.

If it wasn't a pretty short fall, than some other agent must have intervened to absorb fall energy, for example the rope slipping at a tension below the activation threshold of the screamer. In that case, whether the screamer had a significant effect or not would depend on the actual fall length; the longer the fall the less effect the screamer would provide.

To slightly elaborate. (Though I think rgold's comprehensive analysis covers pretty much everything.)

Screamers take time to fully deploy they don't deploy instantly. If it takes 0.2ms to deploy and the rope tension at/above the threshold force only lasts for 0.1ms then you would end up with a approximately half deployed screamer.

ie, A partially deployed screamer simply indicates a short time at/above threshold force. And a small amount of energy absorbed by the screamer.

i have 2 of these that i use above micro cams, RPs and manky pins that are sometimes the only gear you have on some climbs ...

do they work? ... who knows ... but anything in said situations that reduces the fall forces on said sketchy gear is a bonus when its between you and the ground ...

as a bonus they are reusable ... so you arent paying 20$ per pop ;)

oh and i scream alot as well =P