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Operating under special use permit from the Uncompahgre National Forest, Grand Mesa National Forest,
Black Canyon of the Gunnison National Park, Denali National Park
Black Canyon of the Gunnison National Park, Denali National Park
Copyright 2000/2011 Rigging for Rescue®, LLC - (970) 325-4474 - info@riggingforrescue.com - PO Box 745, Ouray, CO 81427
Two-Tensioned Rope Lowers:
Centrally Focused Bridle Attachments
Centrally Focused Bridle Attachments
Many rescue teams operate their rope rescue stretcher operations with either:
a single tensioned mainline coupled with a separately managed belay line
or
two tensioned mainlines without a separate belay line - often referred to as 'Two-Tensioned Rope Lowers'.
Two-Tensioned Rope Lower configurations generally include two separate lines attached to the rescue package (patient, attendant(s), and stretcher), each supporting approximately half of the total mass. These configurations are rigged with a variety of stretcher bridle attachments, friction devices to manage the descent, attendant and patient tie-in methods, as well as rope types.
In 2003, we conducted a series of drop tests that focused on certain stretcher bridle attachment methods in a selection of Two-Tensioned Rope Lower configurations. The 2003 drop test series looked exclusively at stretcher bridle configurations that included two separate bridles and respective mainline attachments. The findings of that drop test series were presented at the ITRS 2003 in Salt Lake City.
The primary focus of this presentation is on Two-Tensioned Rope Lower configurations that incorporate a centrally focused stretcher bridle attachment method. This presentation will share the results of some failure analysis drop testing whereby we simulated a variety of modes of failure. The testing was conducted in order to examine the outcome to the rescue package using certain combinations of rope type and size, rescue mass, fall factor, descent control device, gripping ability, mode of failure and Two-Tensioned Rope Lower method. The material presented seeks to offer some direction in answering the question, "Can a given Two-Tensioned Rope Lower system arrest the fall of the rescue mass given certain system failure circumstances?"
a single tensioned mainline coupled with a separately managed belay line
or
two tensioned mainlines without a separate belay line - often referred to as 'Two-Tensioned Rope Lowers'.
Two-Tensioned Rope Lower configurations generally include two separate lines attached to the rescue package (patient, attendant(s), and stretcher), each supporting approximately half of the total mass. These configurations are rigged with a variety of stretcher bridle attachments, friction devices to manage the descent, attendant and patient tie-in methods, as well as rope types.
In 2003, we conducted a series of drop tests that focused on certain stretcher bridle attachment methods in a selection of Two-Tensioned Rope Lower configurations. The 2003 drop test series looked exclusively at stretcher bridle configurations that included two separate bridles and respective mainline attachments. The findings of that drop test series were presented at the ITRS 2003 in Salt Lake City.
The primary focus of this presentation is on Two-Tensioned Rope Lower configurations that incorporate a centrally focused stretcher bridle attachment method. This presentation will share the results of some failure analysis drop testing whereby we simulated a variety of modes of failure. The testing was conducted in order to examine the outcome to the rescue package using certain combinations of rope type and size, rescue mass, fall factor, descent control device, gripping ability, mode of failure and Two-Tensioned Rope Lower method. The material presented seeks to offer some direction in answering the question, "Can a given Two-Tensioned Rope Lower system arrest the fall of the rescue mass given certain system failure circumstances?"
Rigging for Rescue is producing this video for
promotional purposes. It is not comprehensive
and is not intended to be instructional. Further,
Rigging for Rescue reserves all intellectual
property associated with this video.
Drop 8: The BCCTR Belay Competence Drop
Test Method of a 1m drop on 3m of rope with
a 200kg test mass. This drop simulated a
failure of one of the two lines in a Two
Tensioned Rope Lower system. The DCD was
a Figure 8 plate and a mechanical hand was
used on the running end of that DCD. The
mechanical hand was pre-set with 425N of
gripping ability - the maximum observed grip of
a rescuer with a gloved hand as per the
Gripping Ability on Rope in Motion Study.