MJenkinson
Member
Fulk said:I'm not sure that nihil will understand '"it be reet" '
Fingers crossed for google translate...
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To c?e biti u redu
Chest Ascender - time for a new one
- Thread starter Roperat
- Start date
Fingers crossed for google translate...
?? ?? ???? ? ????
To c?e biti u redu
Mark Wright
Active member
The markings on products such as ascenders and descenders can certainly be very confusing, particularly when it comes to maximum loads.
Crolls have 140kg actually marked on the back of the device and the Turbochest has 120kg marked on the back of it, or at least the ones on the Camp website do. If your Croll doesn't have such markings then it is probably quite an old one. My new Croll is marked with 140kg.
Rather than it being a 'trend' to mark products in such a way it is actually a legal requirement for manufacturers to mark the weight used during the testing to the various standards.
As far as EU standards are concerned the minimum test weight is 100kg, which is to represent a worker and their tools. For industrial purposes the US market require a test weight of 140kg which is why Petzl test their products with 140kg in order to be able to sell in this market.
If the Turbochest is only marked with 120kg then this suggests it wouldn't pass the various tests with 140kg otherwise they would have tested it with 140kg.
There are a number of tests products have to pass in order to gain the EN567 or EN12841B standards including FF1 drop tests and static load tests. Overloaded ascender devices don't usually break, they just damage the rope they are attached to. According to the above standards they should be able to hold a 450kg load before damage to the rope occurs. Petzl ascenders will generally hold 600kg before rope damage occurs.
When you ask about rescue use I assume you mean can two people be suspended from an ascender?
The answer to this is yes, but you have to be very careful to avoid any dynamic loading. This would be the same advice for any toothed ascender device.
Mark
Crolls have 140kg actually marked on the back of the device and the Turbochest has 120kg marked on the back of it, or at least the ones on the Camp website do. If your Croll doesn't have such markings then it is probably quite an old one. My new Croll is marked with 140kg.
Rather than it being a 'trend' to mark products in such a way it is actually a legal requirement for manufacturers to mark the weight used during the testing to the various standards.
As far as EU standards are concerned the minimum test weight is 100kg, which is to represent a worker and their tools. For industrial purposes the US market require a test weight of 140kg which is why Petzl test their products with 140kg in order to be able to sell in this market.
If the Turbochest is only marked with 120kg then this suggests it wouldn't pass the various tests with 140kg otherwise they would have tested it with 140kg.
There are a number of tests products have to pass in order to gain the EN567 or EN12841B standards including FF1 drop tests and static load tests. Overloaded ascender devices don't usually break, they just damage the rope they are attached to. According to the above standards they should be able to hold a 450kg load before damage to the rope occurs. Petzl ascenders will generally hold 600kg before rope damage occurs.
When you ask about rescue use I assume you mean can two people be suspended from an ascender?
The answer to this is yes, but you have to be very careful to avoid any dynamic loading. This would be the same advice for any toothed ascender device.
Mark
nihil_enochian
New member
Haha, yes google translated this very well.MJenkinson said:Fulk said:I'm not sure that nihil will understand '"it be reet" '
Fingers crossed for google translate...
?? ?? ???? ? ????
To c?e biti u redu
Thank you everyone for great replies, especially Mark Wright.
I attached photos of my new CT croll and you can see what I mean. I just don't understand how this new little Petzl croll have 140kg max load, and my CT only 100kg. For the reason that I have read on this forum I didn't want to buy Petzl, so instead I bought this one. I also read some very good reviews on his forum about CT ascenders.
Yes, I was meant on that.
I want to say that this is far most the best forum about caving that I visited. We don't have in Serbia something like this. But we have some great caves and pits.
Attachments
Simon Wilson
New member
The right choice. CT is by far the best chest ascender.
nihil_enochian
New member
Simon Wilson said:
You are right, I also like it, but as I sad before I am concerned about that 100kg max load. Someone told that this happens if equipment is old but if you look at the serial number, it points that it is manufactured in 2016. I also found out that the company which produces Climbing Technology ascenders also produce same products for ABC, REPETTO, SINGING ROCK, EDELRID, and on some of those devices you can not find that markings. You probably know about this website but I'll add a link in any case. You can see there what I mean.
http://storrick.cnc.net/VerticalDevicesPage/AscenderDevices.shtml
Simon Wilson
New member
I don't think we need to be concerned about variations in safe working load figures marked on the ascenders.
What we need to think about is how we use them in caves.
It is well known that new ascenders with toothed cams will tear the rope at around 4kN. A force higher than that could happen by falling so don't use ascenders in a situation where you could fall onto them - that's fundamental and we all know that.
That 4kN figure has been arrived at by testing new ascenders with perfect sharp teeth on brand new rope. But we all use ascenders that are worn to some degree and that will change how they work. Most cavers will stop using an ascender when it starts to slip. I am not aware of any research into what load will cause slippage of worn ascenders. I guess there will be an amount of wear at which which a high load will cause slippage before tearing the rope. This is complicated by the fact that caves are muddy and we can't avoid using muddy rope.
The complex variables that occur in the real world have not been rigorously tested but cavers need to be more concerned with what happens in reality than the figures reported by manufacturers.
My experience has been that I tend to notice slippage when hauling a heavy load. If a caver envisages having to load an ascender higher than normal then they need to consider wear and mud.
The change to using stainless steel parts on the Petzl Croll has meant that it wears at least twice as fast as other ascenders.
What we need to think about is how we use them in caves.
It is well known that new ascenders with toothed cams will tear the rope at around 4kN. A force higher than that could happen by falling so don't use ascenders in a situation where you could fall onto them - that's fundamental and we all know that.
That 4kN figure has been arrived at by testing new ascenders with perfect sharp teeth on brand new rope. But we all use ascenders that are worn to some degree and that will change how they work. Most cavers will stop using an ascender when it starts to slip. I am not aware of any research into what load will cause slippage of worn ascenders. I guess there will be an amount of wear at which which a high load will cause slippage before tearing the rope. This is complicated by the fact that caves are muddy and we can't avoid using muddy rope.
The complex variables that occur in the real world have not been rigorously tested but cavers need to be more concerned with what happens in reality than the figures reported by manufacturers.
My experience has been that I tend to notice slippage when hauling a heavy load. If a caver envisages having to load an ascender higher than normal then they need to consider wear and mud.
The change to using stainless steel parts on the Petzl Croll has meant that it wears at least twice as fast as other ascenders.
Chocolate fireguard
Active member
Simon Wilson said:
I have never known an ascender to slip (grip the rope but then slide as the load is increased).
I have owned several that stopped reliably engaging with the rope first time of asking, but once gripping continued to do so. I eventually replaced each of them of course, but only after I got fed up of the faff of getting them to engage each time. I always put it down to the spring becoming weak.
It never occurred to me that once gripping they could let go while under load, and I don't think I am alone in that belief.
If anybody tells me they have had that experience I shall be much more careful in future.
pwhole
Well-known member
My new model Croll and Simple both lost the front half of their teeth in a year's use, compared to over two years with the old-style Croll. Additionally, the body of the Croll just melted away at the connection point, but to be fair it had been connected to a steel D-maillon, so I swapped it for an ally one when I switched to the CT ascender (the older, orange model). But even the chest strap was wearing the body faster than I expected. The CT ascender fared fine until I had to do two long ascents on a very filthy rope covered in stone dust, and after the second one, the body had a groove worn in it at the top, so that got binned too! I subsequently bought a new Croll for 'sacrificial' work like this (ironically I didn't do this trip again so it's barely been used), and a TurboChest for 'regular' caving, and which I love.
Photos of all three devices:
Photos of all three devices:
Attachments
Tommy
Active member
Great photos pwhole, looks like you get your money's worth .
How have you found the change to an aluminium omni? I've never used steel (perhaps once) and haven't yet seen that amount of wear.
I wonder how much of a factor different prusiking styles and chest tape tension is?
Simon, do you have the data from your 4 kN tests available? I'd be interested in having a look if that's alright.
I wonder if data like that could be pooled somewhere online for easy and open access?
Is there a facility in the caving library or BCRA that I haven't found perhaps?
.How have you found the change to an aluminium omni? I've never used steel (perhaps once) and haven't yet seen that amount of wear.
I wonder how much of a factor different prusiking styles and chest tape tension is?
Simon, do you have the data from your 4 kN tests available? I'd be interested in having a look if that's alright.
I wonder if data like that could be pooled somewhere online for easy and open access?
Is there a facility in the caving library or BCRA that I haven't found perhaps?
Simon Wilson
New member
They aren't my tests. The 4kN figure is the figure that has been bandied about the caving scene for as long as I can remember. If you do some digging on the internet I think you'll find something about it. As for "easy open access" the manufacturers of rope gear aren't usually very open at all about their testing.
There are some links here https://ukcaving.com/board/index.php?topic=15112.0
Some tests were done on old rope.
Does anybody know how the dispute between the CAI and Petzl ended?
There are some links here https://ukcaving.com/board/index.php?topic=15112.0
Some tests were done on old rope.
Does anybody know how the dispute between the CAI and Petzl ended?
Mark Wright
Active member
EN567 and EN12841B require ascender devices to hold a 4kN load for 3 minutes.
I'm not aware of any other manufacturer being as open about their testing as Petzl. The link below was the Petzl response to the CAI complaint. I'm not aware of EN567 or EN12841B being revoked so as far as I know the link below is how it ended.
https://www.petzl.com/security/sport/recalls/product-information-new-croll?language=en#.WXjs3DOZN8c
The slippage issue that Chocolate fireguard questions has happened to me on a few occasions. In reality the front teeth on a mini Basic ascender was sufficiently worn that if I tilted it forward slightly when applying a load it would judder down the rope a bit until it bit properly.
I carried out some of the field testing of the Basic and Croll down the Berger in 2013. Once i'd finally worked out where the Croll cam handle was by feel I had no problems with it at all. The only issue I had with the Basic was that when I wrapped my hand around the body and stood in the foot loop my finger ends would catch the cam and sometimes stop it closing properly and it would slip. My technique for a new device was soon corrected and it worked perfectly.
My more recent experience with a worn Croll suggests that if you keep vertical it won't slip, but if like me you are a bit top heavy or you have a poor technique resulting in leaning backwards slightly, it sometimes slips when you sit down. It doesn't happen at all when new but pretty much as soon as it gets to the point Petzl suggest retiring it.
pwhole has shown some excellent examples of how far beyond this point some are prepared to go, others on here will likely go further.
Petzl have a new 4mm Croll coming out next year specially for their big beer bellied caver market.
Mark
I'm not aware of any other manufacturer being as open about their testing as Petzl. The link below was the Petzl response to the CAI complaint. I'm not aware of EN567 or EN12841B being revoked so as far as I know the link below is how it ended.
https://www.petzl.com/security/sport/recalls/product-information-new-croll?language=en#.WXjs3DOZN8c
The slippage issue that Chocolate fireguard questions has happened to me on a few occasions. In reality the front teeth on a mini Basic ascender was sufficiently worn that if I tilted it forward slightly when applying a load it would judder down the rope a bit until it bit properly.
I carried out some of the field testing of the Basic and Croll down the Berger in 2013. Once i'd finally worked out where the Croll cam handle was by feel I had no problems with it at all. The only issue I had with the Basic was that when I wrapped my hand around the body and stood in the foot loop my finger ends would catch the cam and sometimes stop it closing properly and it would slip. My technique for a new device was soon corrected and it worked perfectly.
My more recent experience with a worn Croll suggests that if you keep vertical it won't slip, but if like me you are a bit top heavy or you have a poor technique resulting in leaning backwards slightly, it sometimes slips when you sit down. It doesn't happen at all when new but pretty much as soon as it gets to the point Petzl suggest retiring it.
pwhole has shown some excellent examples of how far beyond this point some are prepared to go, others on here will likely go further.
Petzl have a new 4mm Croll coming out next year specially for their big beer bellied caver market.
Mark
Chocolate fireguard
Active member
Sorry, I know I'm not that bright, but I still don't know what is meant by "slip",
Is it what happens with a descender that will not engage with the rope until made to do so but takes weight thereafter (a pain, but even a sensible person might use it to get out of the cave), or is it what happens when a descender that has apparently gripped the rope OK but then gives way under an increasing load (a sensible person would immediately ab back down and sort out an alternative)?
I have had a few of the former but have never heard of the latter happening.
It seems to me that this is an important distinction.
Is it what happens with a descender that will not engage with the rope until made to do so but takes weight thereafter (a pain, but even a sensible person might use it to get out of the cave), or is it what happens when a descender that has apparently gripped the rope OK but then gives way under an increasing load (a sensible person would immediately ab back down and sort out an alternative)?
I have had a few of the former but have never heard of the latter happening.
It seems to me that this is an important distinction.
Mark Wright
Active member
When an ascender is new and all the teeth are intact it is the teeth at the very top of the cam that engage first and then the rest of the cam teeth dig in as the full load is applied.
If its badly worn and, e.g. the top and second set of teeth have worn down with flat tops or worn off completely then it will be the spring action of the cam that holds it in place on the rope when it has no weight on it.
As you gradually apply your weight it can slip down the rope slightly until the next row of sharp teeth dig in and then you are OK.
Mark
If its badly worn and, e.g. the top and second set of teeth have worn down with flat tops or worn off completely then it will be the spring action of the cam that holds it in place on the rope when it has no weight on it.
As you gradually apply your weight it can slip down the rope slightly until the next row of sharp teeth dig in and then you are OK.
Mark
Simon Wilson
New member
It's a lot more complicated than that. The teeth might be worn in the middle of the cam. There is a complex relationship between rope size and characteristics, mud, wear and slippage and there's positive feedback in which slippage vastly increases the rate of wear.
Mark Wright
Active member
Simon Wilson said:
You would have to be using very thin ropes for the teeth in the middle of the cam to wear before the teeth at the top of the cam.
Mark
