The Petzl ZigZag debacle has proved one thing: the operating reality for tree climbing gear is a little different to other height safety disciplines - see previous 'Tree Climbing PPE Standards' blog here.
In the post ZigZag world some tree climbers claim they will only buy gear from manufacturers who know about the rigors of treework - think Treemagineers, ART etc.
Manufacturers with tree climbing advisers like Teufelberger, DMM and ART have a far greater tolerance for investment in safety features, sometimes well over-and-above accepted standards, to accommodate the operating realities of aerial arb.
If you are not sure what those operating realities might be we have listed seven 'potentials' below to help you gain some perspective.
Tree climbing gear, custom or configured, built without factoring-in operating realities like these is bound to fail in the market:
1) A single unknown and 'un-rated' anchor point
Traditional height safety proponents are horrified with the concept of a climber dangling 30-meters from the ground, on a single line, secured to, what appears to be, a 'twig'.
Tree climbers make a choice about anchor security every time they climb a tree. In most cases that choice is made while observing the chosen anchor point from one perspective, the ground, sometimes up to 40 meters away.
And, tree climbers are dealing with an organic object. Unlike a rated connection point on a building or other man-made structure tree anchors fail no matter how diligent the climber might be!
2) A spatial aspect to anchor loads and rope management
Traditional rope access has a passive load (the climber) descending and moving sideways. Ascents are short. Anchors are (in theory) predicable and the force angles applied to that anchor are almost always 2-dimensional: up, down and sideways - never through!
The 3-dimensional nature of tree climbing introduces stress to the anchor and the friction device attached to the climber.
Limbs and branches present barriers, forcing specific routes through the tree, all of which increase friction on the climbing line and subsequent stress on equipment.
3) Small 'falls' will occur in tree climbing
500 mm of slack generated in a DbRT single line is the accepted standard in tree work. In all other height safety disciplines this amount of slack is akin to a 'fall'.
And yet tree climbers are almost blazé about slack management.
Sure, you'll be picked up in a TCC for having over 500 mm of slack in your line but there is no one on the work site calling such regulation - slack management is left entirely up to the climber.
The very nature of tree climbing means slack is introduced: stepping up onto a branch, pulling too much through a Hitch Climber system, catching a twig with a resulting snap, shimmying down a spar… there are dozens of examples where slack, or small falls, occur in aerial arb - so you better be sure your gear can handle this reality.
4) Cross-loaded connectors are likely
Slack in the system, as mentioned Reality 3, allows the connector to easily cross-load.
All competent tree climbers are ever vigilant for this phenomena because they know how easy it can happen.
Attend the ITCC, where the world's elite climbers demonstrate their skills, and you'll still see plenty of cross-loaded carabiners… if this is the world's best in action, imagine how many times connectors are cross-loaded in the real-work-a-day-world.
Combine the cross-loaded connector with Reality 1, 2 and 3 and you have a problem - as Petzl have discovered with the ZigZag.
5) Individual, sometimes complex, configurations
Tree climbing is a mix-and-match affair… and you better believe it!
By and large tree climbers are not contrary for the sake of it. Trees are organic. Every work site… and every tree is different.
Historically, tree climbers have poached ideas, techniques and equipment from other disciplines and applied these concepts to tree work. It's in a tree climbers DNA to experiment with gear configurations.
The result, no 'absolute' system or configuration is employed universally in tree work.
Unknown configurations presents a real challenge for regulators and the owners of tree climbing equipment brands.
Proprietary systems can be made compatible but brand owners have no idea how their equipment might finally be configured in the field. If a product fails, the manufacturer will bare the brunt of criticism.
6) Obstructions are common
Branches, twigs, leaves etc, all part of a living tree, somehow manage to find their way into devices, knots and/or complete systems.
A failed anchor can mean a drop to the next branch with the subsequent dynamic load to the climbing system.
Gear has to be designed to handle the unpredictable environment presented in a tree.
Obstructions can also cause the climber to move outside the expected angles, stressing the anchor point, as noted in Reality 1 and 2.
7) Tree climbers work position on a single line
All tree climbing equipment should be manufactured to handle climbing (ascent, descent and work positioning) on a single line; whether in a doubled or a single leg configuration.
Most of the gear currently available does allow for such activity; the rope, harness, lanyards etc. It's the choice of friction device where challenges are presented.
Like it or not climbers today will experiment with 'SRT' work positioning when they purchase an new friction device (you can blame the Rope Wrench for this one).
Rather than fight this operating reality, manufacturers should be factoring in such usage - think Rock Exotica Unicender - the Uni can be utilized in either format.
Gear will break if variables like those above are ignored!
Inferior tree climbing equipment will quickly be identified.
Any one of the above 'operating realities' could find the weak spot in a new piece of kit but, oftentimes, all seven variables are playing together concurrently during tree climbing maneuvers.
Safety factors, accommodating these tree climbing variables, must be designed into the product before it leaves the factory.
To date, that's why tree climbing gear designed by tree climbers has proved to be the most robust.
