RAD LINE: small-diameter hyperstatic cord
The cord sold with the RAD SYSTEM was carefully chosen to be suitable for the intended uses, while remaining compact and lightweight. Its specific qualities limit its application: it is not as versatile as a normal mountaineering rope.
Warnings
- Carefully read the Instructions for Use used in this technical advice before consulting the advice itself. You must have already read and understood the information in the Instructions for Use to be able to understand this supplementary information.
- Mastering these techniques requires specific training. Work with a professional to confirm your ability to perform these techniques safely and independently before attempting them unsupervised.
- We provide examples of techniques related to your activity. There may be others that we do not describe here.
1. Falling on a hyperstatic cord is dangerous
The rope is an essential component; its energy absorption capacity helps reduce the maximum impact force experienced in a fall. Dynamic ropes have greater energy absorption capacity than static ropes.
Comparison test of energy absorption by the rope:
Fall factor: FF 0.4.
0.8 m fall on 2 m of rope with figure-eight knot in each end, knots tightened with 80 kg.
80 kg dummy.
Note:
The test scenario does not correspond to a realistic belay situation; the goal is only to characterize the ropes’ behavior without measurement bias.
A hyperstatic cord has minimal elasticity; it can not absorb the energy of a fall.
- High impact force (peak height of the blue curve)
- Sudden deceleration (slope of first peak of the blue curve)
The RAD LINE hyperstatic cord must not be used to arrest a fall... unless another element of the system is able to absorb the energy of the fall.
Examples of energy absorption factors in addition to the rope:
- free movement of the belayer
- rope friction, for example cutting through the lip of a crevasse
- energy absorbers integrated into the system
2. Compatibility with ascenders
The RAD LINE cord sold with the RAD SYSTEM is 6 mm in diameter. The MICRO TRAXION, NANO TRAXION and the TIBLOC are certified for diameters greater than 7 mm. To offer a kit with the RAD LINE and these ascenders, Petzl did a series of tests to ensure their compatibility. The main characteristic limiting the compatibility of a cord with a progress-capture pulley is the cord’s tear resistance. Note: the ascender standards require a tear resistance of 4 kN on compatible ropes.
Test of the RAD LINE’s tear resistance with MICRO TRAXION:
Strength of the cord’s sheath greater than 5 kN
Test of the RAD LINE’s tear resistance with NANO TRAXION:
Strength of the cord’s sheath greater than 5 kN
Test of the RAD LINE’s tear resistance with TIBLOC (with ATTACHE or Sm’D carabiner):
Strength of the cord’s sheath greater than 4 kN
Test of the RAD LINE’s tear resistance with other ascenders:
Wide range of results: cord sheath breakage observed at between 2.9 and 5 kN depending on the ascender.
Other compatibility limits:
With certain ascenders, the cord’s thinness can be incompatible with the geometry of the blocking system: for example the cord can come out of the ascender, or blocking may be insufficient. This is not the case with MICRO TRAXION, NANO TRAXION and TIBLOC.
With RAD LINE, use only the ascenders specified in this document. For any other ascender, follow the recommendations of the Instructions for Use furnished with the ascender.
Only MICRO TRAXION, NANO TRAXION and TIBLOC have been validated for use with the RAD LINE cord in the RAD SYSTEM.
