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EN 892 standard confounds tree climbers?

EN 892 standard confounds tree climbers?

Richard Tregoweth - Monday, August 15, 2011

EN 892 is the standard test used to rate rock climbing lines. EN 1891A is the standard used for tree climbing lines.

Read it once and then read it again!

You'll notice one major difference between these two standards: namely the 22kN break strength of the rope.

Tree climbing lines (EN 1891A) must have a minimum strength of 22kN while rock climbing lines (EN 892) have no such measure. The lack of a 22kN rating serves to confound tree climbers who look for this number when they purchase equipment.

Under normal circumstances dynamic rock climbing lines are not used for tree climbing. Consequently, not much thought is given to the EN 892 standard or its testing methods by tree climbers.

But there have been a number of situations recently where understanding the EN 892 standard has become necessary.

The first involved the ITCC Rules Committee debacle (2010) regarding the use of ultra-static, Dyneema core foot lock lines. The resulting ISA 'Caution Notice' made a suitable 'shock absorber' mandatory when foot locking on ultra-static lines.

For a period after the Caution Notice was announced dynamic rock climbing lines (as the foot locking prussic) were considered an alternative to the ISA suggestion - rather bulky 'zip' absorbers as used in other height safety applications.The ISA Caution Notice has since been withdrawn - no reasons were given for the reversal.

The second, more recent example, centers around the use of the Trango Cinch as a lanyard adjuster.

The Cinch was primarily designed as a belay device for use with EN 892 rated dynamic rock climbing lines - see picture below. Innovative tree climbers, looking for an alternative lanyard adjuster to the rope grab, the ART Positioner, or even the humble prussic itself decided the Trango Cinch was perfect for the job.

The Cinch happens to have a relatively narrow rope diameter operating window - 9.4mm - 11mm to be precise.

Due to this specification, a rope with a 10mm diameter runs best through the device yet still grabs sufficiently quickly to work as a lanyard adjuster. 10mm Armor-Prus has become the rope of choice for the Cinch lanyard.

But Armor-Prus is not rated to EN 892. Actually, Armor-Prus is is at the other end of the rating spectrum when it comes to ropes - it is considered ultra-static due to its Dyneema core.

Technically speaking, none of the tree climbing lines commercially available today (EN 1891A) are suitable for use with the Trango Cinch. That is, if you were using the Cinch as a belay device.

So, if you intend following Trango's specifications literally you better start reading up about EN 892.

And… be prepared to explain the differences between EN 892 and EN 1891A if you are a competition tree climber using the Trango Cinch as a lanyard adjuster with an EN 1891A or ultra-static lanyard - the gear check discussions should be interesting!

For the record, Treetools believes the Trango Cinch can be used as a lanyard adjuster with both EN 1891A and ultra-static lanyards in specific circumstances - we'll blog separately on this issue.

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