I'm certainly not here championing Petzl's cause, merely trying to put some sort of rational argument forward to counter the hysterics that have been posted on the previous page. I should say that I don't own and would never buy a zigzag, and have spoken out against them in other threads, but when it comes to manufacturing of heights safety equipment, Petzl has no real competition. I think in general many other rope access companies could learn from them.
I'll agree it's odd to have a failure so soon, but that doesn't mean it couldnt happen with other similar products as I have mentioned. It also doesn't mean that there would be a second failure in 3 months time, or ever, if nothing was done about the design. I think this really was quite a freak accident. Regardless, it will be corrected as it ought to be. Will other companies with much smaller R&D and testing departments, and a much looser testing regime now go and revisit their products? I think not.
As for your very valid question of why 15kn and not the more widely adopted 22kn standard for general life support, I don't have an answer. Im guessing it's partly because of the doubled rope system we use meaning that the product really only need be rated for 11kn to be the equivalent of an SRT product rated at 22kn. I don't know the spec for the unicender, spiderjack etc, but I would guess that they wouldn't be rated for 22kn either. I know from reading many independant tests of different styles of prussik knots that many of the knots we use every day slip at 4kn-6kn, and fail at 10-12kn. I can dig up some links for these if you'd be interested.
I'll agree with that trend you mentioned, but thats the way of mountaineering/rock climbing products. The products are designed with a target market in mind. Petzl makes many different types of products. Some, like the croll, gri gri and pantin are designed for markets where light weight is of importance. They are not intended for industrial use. Their industrial and rescue products are much more substantial, higher rated, better made, and appropriately priced. I have the older croll (a couple of them), an original, and a second generation grigri and have owned the pantin which I very much disliked. I own and use the CMI ascender and much prefer it.
None of those points change the subject of the zig zag, it's failure, what ought to be done about it, and whether other products from other manufacturers may be at risk of a similar failure. My opinion is that the failure was a freak accident, and that other similar products from other manufacturers are at risk of similar failures under the same circumstances. Petzl will address the problem, and find an appropriate solution. By then it will have hurt their entry into the tree products segment very badly, which is a shame because they have brought out some quite good products (sequoia swing harness, ascentree, treesbee etc). I think it's a good thing to see a major player like Petzl taking the tree service industry seriously, and designing products specifically for our use.
Shaun
