The controversy over Petzl’s Zigzag continues, as further photos of cracks and fractures of links are posted on social media. Richard, over at Treetools NZ, has some interesting thoughts on the matter as to why people are responding the way they are.

One interesting comment on Treebuzz, I thought, was made by a person who categorically rejected any doubt out of hand regarding this device. His point being that nowadays people expect gear to be made bombproof, able to withstand anything thrown at it – and that that is an unreasonable expectation. He remains adamant that ZZ is safe to use and that he will just be careful with it.

This got me wondering. After all, one part of treemagineers’ activities revolves around contributing towards developing products for work at height. So what is my position in regards to this?

Yes, I agree, it is an unreasonable expectation to have of a piece of equipment that it will stand up to anything you throw at it. It won’t. Unless it is massively over-engineered, of course, but that will tend to add on lots of weight in form of extra material.

Traditionally, this is how US-based harness manufacturers went about things. As they had less clearly-defined testing parameters to work towards, they would just add on lots of extra material. If in doubt, make it bombproof. European manufacturers, equipped with a much more concise set of performance criteria that their harnesses need to conform to, were able to refine their design towards that goal. The irony is, of course, that regardless of whichever route you take, wear and tear is still going to happen. On the contrary, I sometimes wonder whether it is not preferable to have clearly defined wear parts that are easy to inspect and replace at regular intervals, as opposed to massively over-built, clunky elements that are hard to visually assess and are not, anyway, as the user assumes that they are bombproof and consequently do not need inspecting.

Bombproof against what? This…


What does bombproof mean anyway?

Probably depends on the size bomb we are talking about – and remember there are some quite sizable ones out there! Bombproof is a misnomer. It is supposedly implying that something is extremely robust – without offering any further quantification.

... or this?
… or this?

Let us try and be more precise in describing the qualities of that robustness.

One easy way to do so is to refer to standardised testing parameters and set-ups that the piece of equipment has passed. Further, a manufacturer shall endeavor to consider foreseeable failure mechanisms and to either warn against these in their user instructions or to adapt the design to counter that risk.

I am amazed by how at the moment people seem to be putting gear out there without giving much (if any) thought to testing. Probably they have abilities that I lack, but I will be the first to admit that whilst a piece of kit may superficially seem fine, whilst we may have climbed the prototypes and it all feels great – I still remain totally ignorant of how it will bear up under extreme loads, as can occur as result of a fall. Or how it will withstand the many load cycles under low load it will be exposed to over a lifetime. For this reason treemagineers have invested considerable amounts of money, time and effort allowing us to build up our background knowledge about every product we have been involved with. Not because referencing testing gives you an air of sophistication (it does not), but because it helps us ensure that we have done all we can to ensure that the equipment behaves the way it has been designed to. In my opinion this is a no-brainer, not just from an ethical, but also from a liability point of view.

It is certainly not an area to cut corners in.

It is worth considering also, that as an end user, this is part of the package you buy into. You have a right to expect that the manufacturer has gone to appropriate lengths to ensure your safety. If you feel you have been furnished with insufficient data in regards to understanding the performance criteria a piece of kit you have just bought fulfills, do not be shy to request that information – and carry on doing so until you are satisfied.

Blind belief is misplaced when it come down to assessing PPE. After all, it is your life you are putting on a line! Demand clear and unambiguous answers.