In this PRO Tip, Senior Rescue School Instructor LeRoy Harbach considers more suitable products that can be used for collection points in rigging as an alternative to the Figure 8 Descender, which is not recommended for this application.
Over the years CMC has received questions from users regarding the use of a Figure 8 descender as a collection point for rigging anchors, high lines and litters. For many years, the large symmetrical hole made it the best choice of equipment available at the time. The practice is losing favor for 3 reasons:
- The product is being used in a manner not intended by the manufacturer.
- The product has not been tested in the collection point configuration.
- More suitable products now exist for the application: O-rings, anchor plates and tri-links.
The use of a product in a manner not intended by the manufacturer can transfer the liability for any damage that occurs to the user. The question is complicated in the rescue field because rescuers are frequently required to adapt equipment and procedures to meet the needs of the incident. For liability reasons, use the proper equipment for the purpose unless there is a compelling reason to do otherwise, as supported by the principles of your training and your team’s approach to unique scenarios with limited resources.
Figure 8 descenders vary regarding material, shape and the manufacturing process. The smaller drop-forged aluminum 8s intended for rock climbers may lack the strength needed for a system collection point, however, those machined out of aluminum plate and the steel models are better suited to a wider variety of rescue applications.
The ears on the Figure 8s designed for rescue descent have the potential for creating a problem when carabiners are clipped into the large hole. When the system loads, there is a chance a carabiner gate could hang up on an ear resulting in cross-loading of the carabiner or unintentional opening of the gate.
Steel O-rings are a good choice for a collection point because of their high strength, symmetrical shape, and lower cost.
The CMC Anchor Plate is designed to be a more efficient collection point when rigging anchor systems. Our experience in CMC rescue classes demonstrates that anchor plates make it quicker to set up systems and we see fewer mistakes. The large hole acts as the collection point. The small holes make it easy to attach and remove carabiners holding descenders, pulleys, MPDs or other equipment. Depending on their rated strength, most anchor and rigging plates should provide a safer more efficient collection point than using a Figure 8 descender.
Based on these considerations, CMC does not advocate the use of Figure 8 descenders as collection points.