Backing-up the ASCENTREE with the ZIGZAG during tree access - Petzl Canada
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Backing-up the ASCENTREE with the ZIGZAG during tree access

Lightweight technique that enables access and work in the tree with minimal equipment.

Warnings

  • Read the technical notice before viewing the following techniques.
  • It is important to fully understand the information provided in the technical notice before using this complementary information
  • Mastering these techniques requires training.
  • Consult a professional before attempting to perform these techniques on your own.



Note: in this document the name ZIGZAG means either the ZIGZAG or ZIGZAG PLUS models.

There are many access techniques suitable for different work objectives in the tree. The access technique includes a choice of rope installation, and the ascent technique itself.

Two precautions are recommended during access:

  • During ascent, the ASCENTREE's cams should be backed up, for example with friction hitches.
  • The user must be able to descend in an emergency, without significant change to the equipment setup.

The ZIGZAG is connected to the ASCENTREE with a sling and installed on the rope that is used for both access and work. Arriving at the top, the ZIGZAG is on the splice side, ready to be set up for the normal work configuration. This technique is more suited to setting up the ZIGZAG in double mode for work, although a single-mode setup with the CHICANE is possible.

ZIGZAG, access and work.
ZIGZAG, access and work.

Access

ZIGZAG, access.

Advantages

  • Uses minimal equipment.
  • Efficient ascending as the work rope is not carried by the arborist.
  • The rope length, required for the work phase and the descent, is verified during access setup.
  • The rope joining knots, placed at the top, ensure no knot passing in case of emergency descent, or rescue.
  • The selection of EXPRESS sling length allows the ergonomics to be adjusted for the ascent.

Disadvantages

  • Work is not possible during the access phase.
  • Without an access rope left in place during the work phase, the possibilities of aid or rescue by the ground person are reduced.
  • In case of emergency descent, the rope running over the branch can damage the bark.
Information

Precautions

The ZIGZAG must be installed on the blocked rope strand. The quick link on the ASCENTREE must be tightened with a wrench. The knots must be moved up as close as possible to the branch for the strand to be correctly blocked.

Remarks on the ZIGZAG backup

  • If the cam on the blocked strand opens, the ZIGZAG functions normally in double mode.
  • If the cam on the other strand opens, the climber is held by the cam on the blocked strand (the rope must be tightened around the branch).
  • Warning: if both cams open simultaneously, the arborist will be hanging from the ZIGZAG in single mode. This situation is acceptable in this special case, on the condition that the arborist does not move. It is recommended to quickly make a backup knot on the rope, below the ZIGZAG, before re-engaging the cams to continue the ascent

Installing the access system

ZIGZAG, installing the access system.
ZIGZAG, installing the access system.

Emergency descent (during the access phase)

Disengage the cam on the blocked strand and remove the rope from that side of the ASCENTREE. Close the cam. Use the ZIGZAG normally in double mode.

Warning: do not disengage the two cams to attempt to descend with the ZIGZAG in single mode.

Information

Tip

The ZIGZAG must be installed on the blocked rope strand. The quick link on the ASCENTREE must be tightened with a wrench. The knots must be moved up as close as possible to the branch for the strand to be correctly blocked.

ZIGZAG, tip for emergency descent.
ZIGZAG, emergency descent.

2. Arriving at the top

Once at the top and anchored in, the arborist can dismantle the access system and disconnect the strands of access rope.

ZIGZAG, arriving at the top

3. Work position

The ZIGZAG is close to the splice, in the normal work configuration.

ZIGZAG, work position.
ZIGZAG, work position.
Information

Precautions

Optimize the quality of placement of your connectors, to avoid any rubbing or poor positioning that presents a risk of opening or breaking the carabiner. In case of doubt, use steel connectors certified to the ANSI Z359.12 standard, which have locking sleeves that can withstand external and side loads of 16 kN. Note: this strength does not protect against the risk of accidental opening due to rubbing. If you are unable to mitigate the risks of rubbing and/or poor positioning of the connectors, use a different technique.