Standards Testing
SRT and DdRT
Single Rope Technique (SRT) and Doubled Rope Techniques (DdRT) are somewhat subjective terms that
can mean slightly different things to different people and different organizations. Other names for Single
Rope Technique are Static Rope Technique or Dynamic Rope Technique. SRT as referenced in these
instructions simply refers to any means or methods of ascending and descending a tree on a single leg of
rope that does not move with the climber.
For more information on the meanings of these terms, refer to the following resources:
International Society of Arboriculture: www.isa-arbor.com
Tree Care Industry Association: www.tcia.org
On Rope, by Bruce Smith and Allen Padgett (ISBN: 978-1-879961-05-0)
Best Practices for SRT in Arboriculture, by Donald Coffey and Tchukki Andersen
(TCIA publication)
Single Rope Technique, by Joe Harris (The Victorian Tree Industry Association)
http://vtio.org.au/Content/wp-content/uploads/2010/07/Single-Rope-Technique-i.pdf
The Rope Wrench system is not CE marked even though the individual components are but this is
entirely outside of our control for the following reason. There is a clear ruling from the VG11 Group
(group of european notied bodies responsible for standards relating to protection of falls from height)
‘Recommendation for Use (RfU) CNB/P/11.088 dated 12/10/11 states that ‘a system that relies on
knots being tied by the end user are not suitable to be certied, as they rely on techniques’.
However following our recent discussions with the UK CE Test House they were prepared to test the
system in accordance with EN353-2 (Guided type fall arresters including a exible anchor line) and
provide an independent Test Report to conrm that the system is fully compliant with the relevant EN
Standard.
ISC are aware that the industry uses a huge variety of hitch combinations, and it is the hitch that
dictates the effectiveness of the whole system. The Rope Wrench itself is not a fall arrest device, it is
a friction management device. Since hitches are not within ISC's eld of specialism and, at least in
theory, cannot be CE marked according to their manner of use, the user should satisfy themselves (in
conjunction with the hitch cord manufacturer, their industry association and industry best practice) that
the hitch they prefer to use is an effective means of fall arrest (with or without the Rope Wrench). The
testing we have carried out on the various congurations is a good way to do that.
Throughout 2017 we had further discussions with the German ‘Insurance’ Organisation SVLFG
(Sozialversicherung für Landwirtschaft, Forsten und Gartenbau) who had raised a concern about system
compliance. Eventually we agreed that if by suitable testing it could be proven that the system in
certain congurations was compliant with the EN Standards then that would be sufcient to prove that
the system was ‘t for purpose’.
We provided evidence that, in 2014, in conjunction with the ISA Technical Advisory Committee (TAC),
the system was extensively tested in accordance with the relevant European Standards and meets or
exceeds the performance criteria of the standards and therefore was deemed safe/ t for purpose and
so it was decided to expand upon that but with a greater number of congurations. However SVLFG
required that, for credibility, the testing should be done by a recognised CE Test House.
In order for the system to be submitted for testing in accordance with the relevant standards, ISC have
to submit a complete system. ISC has worked closely with leading rope manufacturers to establish
combinations that will provide best performance under the various test parameters.
The following 3 commonly-available congurations were tested and conrmed as fully compliant:
1. Yale Kernmaster 11mm & Yale Beeline Blue 10mm, 65cm tied in a 4 wrap/ 2 braid VT
2. Stein Acuda & Stein ATOL TEC 10mm, 65cm tied in a 4 wrap/ 2 braid VT
3. Courant Kanopa Pro & Courant Phoenix 10mm, 65cm tied in a 4 wrap/ 2 braid VT
If a signicant dynamic event on the system should occur, the hitch will slip and limit the peak force
to the user at under 6kN. It is likely that there will be a large amount of heat build-up during such an
event which might result in heavy glazing of both the rope and the hitch cord. After such a dynamic
event, the rope and hitch cord should be inspected for signs of damage and retired if necessary.