In climbing or mountaineering, the rope team offers the highest level of safety.

Nevertheless, fixed-rope solo climbing is an option that many climbers have taken, experimenting with a variety of technical solutions.

Petzl has not developed a device for this activity, but certain ascenders may be used for it by experts.

The solutions proposed in this document take into account known practices and accident records, in order to offer solo climbers a belaying system with, at a minimum, the following qualities:

- effective stopping (belay)

- easy sliding along the rope while climbing

- ease of use

- redundancy of the belay

Petzl does not recommend using only one ascender for self-belaying.

Using a single ascender is technically feasible, however, accidents have been reported despite user expertise.

The risks are real in the field, so Petzl recommends using a system with a secondary belay.

This is because:

- You are moving alone over dangerous terrain

- Mishandling is always possible

- Ascenders are not specifically designed for self-belayed climbing

- It must be understood that all systems are flawed, because this means there is a risk, however minor.

Introduction to the principle of redundancy of the belay

Considering the possible malfunction of a single belay system, the usage of a secondary system is strongly recommended.

The secondary system is "redundant", it is installed as a backup to the first system.

The redundancy of the belay should not be understood as a supplementary constraint, but as a necessary precaution.

Primary characteristics of a secondary belay system:

- No interference with the function of the primary system

Example: contact between the two devices while climbing must be impossible.

- Continuous belay

Example: a lanyard for occasionally resting on a point of protection is not a continuous belay system.

Recommended characteristics:

- It should work differently from the primary system, to limit the risk of repeating the same error

Example: if the primary system is a MINI TRAXION, the secondary system should be another device.

- No increase in complexity of installation or functionality, ease of use at least equal to primary system

Example: if the primary system slides along the rope without the need for manual intervention, the secondary system cannot require manually pulling slack through the device.

【轉自：https://www.petzl.com/US/en/Sport/General-principles-for-solo-climbing-with-a-fixed-belay-rope?ActivityName=Rock-climbing】