VT Prusik for Rescue Belays
VT Prusik for Rescue Belays – Abstract Rope rescue teams typically operate redundant two-rope systems with inclusion of a failsafe mechanism for fall arrest. Examples include the MPD, 540° Rescue Belay, Petzl I’D, and Tandem Prusiks to name a few. Teams operating in remote environments with longer ingress/egress distances often favor lighter weight, multi-purpose systems and devices as part of their overall mission profile. In 2013, Rigging for Rescue began examining the Bluewater VT Prusik (configured as a Schwabisch ‘Max over One’ hitch) as an alternative to the Tandem Prusik Belay. In 2014, this author presented at ITRS quick look tests considering a variety of Aramid fiber friction hitches and configurations. Initial results for the VT Prusik were favorable and thus additional testing was warranted. Further testing was conducted in 2017 and 2019. The purpose was to critically examine the capabilities and limitations of the VT Prusik as a device suitable for managing fall arrest on a rope rescue system while lowering or raising a 200kg mass. Since the 2014 ITRS presentation, three primary areas of inquiry include: The British Columbia Council on Technical Rescue – Belay Competence Drop Test Method (BCCTR BCDTM) Human operators using a snug top-rope while lowering Raising scenarios with a snug top-rope and human operators Additionally, tests were conducted with the tensile testing machine on drop test sample ropes and Prusiks. The laboratory style tests (i.e. BCCTR BCDTM) demonstrated favorable results that were within industry acceptable performance criteria for: Maximum arrest force Stopping distance Integrity of the device and rope system The human operated tests we conducted produced results that compared favorably to other tests we have either witnessed or been made aware of utilizing Nylon TPB (with human operators). Mechanical devices with purpose-built fail-safe mechanisms will undoubtedly prove more reliable for fall arrest versus a user-configured system such as Tandem Prusiks or the VT Prusik. However, for teams with specific mission profiles that place a high value on lightweight, multi-purpose equipment, the single VT Prusik configured as a Max over One, appears to be a superior alternative to the traditional Nylon Tandem Prusik Belay. VT PRUSIK FOR RESCUE BELAYS For more information, check out Rigging for Rescue’s video testing samples.
Mirrored Systems – Reflections From the Edge
ITRS, 2015 Abstract: “Mirrored Systems – Reflections from the Edge” Author: Mike Gibbs, Rigging for Rescue Background What is the primary objective in a technical rope rescue operation? It is to transport the subject from a place of predicament to a position of security – ideally, in a controlled and safe manner. There are many available systems, devices, and risk management approaches to accomplishing this objective. Distilling the alternatives down to a chosen system incorporates many different factors. The unique combination of these factors is driven by the mission profile. Mirrored Systems is one of the more recent technical rescue approaches to be introduced to the rope rescue community. The purpose of this study was to examine a Mirrored System under certain operational conditions in order to better assess the overall system performance and qualities. Methods A Mirrored System incorporating the use of MPD devices on each of the two operational ropes was examined in drop tests utilizing a fire department training tower. The key parameters included: • human operators on the devices• 200 kg test mass (steel plates)• zero free fall (snug toprope)• an artificial high directional in order to eliminate edge contact/friction• a coordinated shared-tension lowering of the test mass for a few meters followed by the intentional failure of one of the two rope systems using a pre-rigged quick release mechanism (at the test mass connection point) The operators of the two MPDs were not informed as to which rope system would be ‘failed’. After each test, stopping distances were measured and the operator of the integral system was interviewed for any notable observations. A total of 51 tests were conducted over the course of two days. Results Based on individual test results as well as operator interviews, it was evident that the MPD on the integral system did not self-actuate following failure of the other line. In other words, the device operator had to first recognize the situation (i.e. their rope accelerating) and then make a conscious decision to disengage the MPD release handle. Conclusion There are numerous benefits to two-rope rescue systems that share the overall tension between both ropes and their respective devices. However, a shared-tension lowering system can incorporate other risks such as the loss of device self-actuation – this would be of particular concern at the initial edge transition, when the system is first being ‘proof tested’. The Mirrored System using MPDs has this quality. A lack of system self-actuation can lead to increased stopping distances as well as the possibility of a complete ground fall. Furthermore, any system will incorporate this risk if it relies on operator action and reaction time to initiate fall arrest. MIRRORED SYSTEMS-REFLECTIONS FROM THE EDGE For more information, check out our testing video series.
High-Modulus Aramid Fiber Friction Hitches in Technical Rope Rescue Systems
PROJECT VIDEOS Abstract In November, 2014, at the International Technical Rescue Symposium (ITRS) in Golden, Colorado, Mike Gibbs of Rigging for Rescue presented on the topic of aramid fiber friction hitches in rope rescue systems. This presentation was based on several different testing sessions over the course of a couple of years. The tests conducted included both slow pull examinations as well as drop testing. Included in this website posting is: • a selection of slides from the PPT given at ITRS• some of the test project video clips• the abstract submitted to ITRS The slides chosen are the primarily the ones that summarize the data from the tests conducted. The entire PPT is not included as it relies on the presenter narrative to properly convey our opinion of the research findings. PPT SLIDES
Multi-Point Anchor Equalization
Considerations for equalizing multi-point anchor systems International Technical Rescue Symposium (ITRS)[/fusion_text][fusion_text] Project Videos: https://youtu.be/oHtoomHZSRc Abstract Building sound anchors is one of the fundamental elements of recreational climbing, rope access, and technical rope rescue. Anchor configuration methods are also some of the most discussed, debated, varied, and perhaps doctrine-based skill sets in the entirety of ropework. However, much of the debate as to which anchoring technique is most appropriate for a given situation is dependent on anecdotal evidence as well as the way that we have always done it. The wide range of anchoring techniques and practices employed across different practitioners, organizations, and disciplines suggests that there is a high degree of unknowns and perhaps misunderstanding within the ropework community. In the spirit of increasing our own understanding of ‘how stuff works’ in anchoring, we chose to examine how dedicating more strands (i.e. material) to a given anchor point affects the overall load distribution in a multi-point anchor system. Additionally, we examined how a knot at a given location in a multi-point anchor system affects the force distributed to the various anchor legs. Our test method focused primarily on 2-point anchor systems with equal length legs. The leg lengths examined were either 1 meter per strand or 5.5 meters per strand in order to compare the effect of different amounts of material for a given test set-up. The research was conducted using a hydraulic ram slow pull machine and resultant forces were captured using electronic dynamometers at each of the two anchor points as well as at the focal point (aka master point of attachment). Over 150 slow pull examinations were conducted on a wide variety of configurations including: 1 strand vs. 2 strands, 1 strand vs. 3 strands, 2 strands vs. 3 strands, etc. Material used included 8mm low stretch kernmantle cord as well as 11mm low stretch rope. We discovered that there is a wide range of force distribution in even the most carefully constructed multi-point load distributing anchor system. Additionally, anchor systems that include a disparate number of strands dedicated to a given anchor point affect the force distribution significantly. And lastly, knots in the anchor system on individual strands affect the distribution further still. As ropework practitioners, when we approach a multi-point anchoring scenario with the intent of equalizing that anchor system, the techniques that we employ will likely have a significant affect on the overall force distribution achieved. Our given practices may be unintentionally favoring individual anchor points more than we intended. The reason that anchor system failures are a relatively rare occurrence likely speaks to just how overbuilt our systems are as a general practice. A more thoughtful approach to the rigging techniques employed in a multi-point anchor system will provide the greatest dividends when the overall quality of anchor points is dubious at best. Ideally this research can provide an impetus for further research in the topic as well as a critical thinking approach to ropework techniques and practices.
Parallel Plaquettes
A lightweight rope rescue system using common climbing equipment International Technical Rescue Symposium (ITRS) Project Videos: View the Complete Report Abstract A current review of rope rescue systems reveals a wide variety of techniques, equipment and risk management philosophies relative to moving live loads over complex terrain. Some teams use a single main line and a separate belay line; others employ the use of two mainlines to support the load without a separate belay. Descent control device choices run the gamut and include brakeracks, cammed devices, 8 plates and belay tubes just to name a few; rescue belay devices/systems are also numerous and include Tandem Prusiks, the Traverse 540° Rescue Belay, the Petzl I’D as well as several other devices. While some teams may elect to employ the use of single rope technique in certain circumstances, others would rarely move a live load without the use of a backup belay system. The reasons for the diversity in all of these subject matters include terrain, regional influences, culture, typical number of respondents, skill and training levels, cost, weight, commonality of equipment, perceived levels of risk, type and size of agency and many other considerations. The nature of the task is improvisational. Because of that quality, the solutions will always require judgment and that alone will ensure a certain level of diversity amongst ‘common industry practices’. One ‘big picture’ theme that seems to be pretty well agreed upon amongst practitioners is: 1. having system-wide auto-stop in place (i.e. the system does not require a human operator to hold or grip something in order to maintain security) The Parallel Plaquettes system is currently being examined as a potential option to meet that key rope rescue principle. The system was not designed for all rope rescue groups for reasons discussed above. For example, it is not compatible with 12.5mm rope. However, for those operating in a mountain rescue environment using smaller diameter rope it has the benefit of being constructed with ubiquitous gear that is likely already hanging from your harness.
Rescue Belays
Important Considerations for Long Lowers International Technical Rescue Symposium (ITRS) Project Videos: View the Complete Report Abstract Incorporating a belay system within a rope rescue system is common practice in rope rescue because, although the probability of a mainline failure is low, the consequence may be dire. Mainline system failures have occurred and will continue to occur, but what happens as a result of those failures will largely be driven by (1) the inclusion or exclusion of a belay system, (2) the specific nature of that system and (3) how that system is managed throughout the operation. The outcome depends on, among other parameters, the length of rope in service. Many studies have looked at belaying with a few metres of rope in service, but little data exists for larger amounts of rope. This paper will describe initial examinations of the problem of belaying on long lowers.
Lanyards Part II
An Examination of Purcell Prusik as Personal Restraint Lanyards Project Videos: View the Complete Report Abstract: In two independent drop test series conducted in 2002 and 2005, we examined the effects of a shock load on to various commercially made and user-configured personal restraint lanyards. Our primary focus in those two drop test series was to test daisy chains and other similar lanyards. We presented our findings at the 2005 ITRS held in Ft. Collins, Colorado. Several of the lanyards examined in 2002 and 2005 demonstrated serious shortcomings in a shock loading scenario due to either (1) excessive maximum arrest force (MAF) and/or (2) the lanyard failed or its condition was severely compromised. One of the lanyard configurations tested in 2002 and 2005 that showed some promise was the Purcell Prusik. Our intent in the 2006 drop test series was to conduct a number of drop tests on Purcell Prusiks in order to gain a better understanding of their capabilities and limitations as a personal restraint lanyard in a shock loading scenario. Our hope was to identify a suitable alternative choice to traditional lightweight personal restraint lanyards such as the daisy chain, for example.
Daisy Chains and Other Lanyards
Some Shocking Results when Shock Loaded Project Videos: View the Complete Report Abstract: Over the years, organized rope rescue has evolved with respect to the techniques used as well as the equipment employed. Much of this evolution can be attributed to the borrowing of techniques, equipment and practices from similar disciplines. For example, many pieces of equipment originally designed for climbing or mountaineering have been adopted by rope rescue practitioners and incorporated into their systems. The ‘daisy chain’ is one example of a piece of equipment originally popularized by aid climbers and later adopted for other uses. The daisy chain has largely become the lanyard-of-choice for climbers as a means of attaching themselves to an anchor point. Because the rope rescue community has such a strong contingency of climbers in its ranks, it is not surprising that the daisy chain is regularly used as a similar tool in rope rescue scenarios. In two independent drop test series conducted in 2002 and 2005, we examined the effects of a shock load on to various commercially made and user-configured lanyards. This presentation offers a critical examination of daisy chains and other similar lanyards.\
Two-Tensioned Rope Lowers
Centrally Focused Bridle Attachments Project Videos: View the Complete Report Abstract: 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.
Two-Tensioned Rope Lowers II
Project Video View the Complete Report 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. Stretcher Bridle Attachment Considerations 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. The primary focus of this presentation is on the stretcher bridle attachment component. This presentation will share the results of some failure analysis testing. The testing was conducted to examine the outcome to the rescue package using certain stretcher bridle attachment methods in a selection of Two Tensioned Rope Lower configurations. The material presented seeks to offer some direction in answering the question, “Would you want to take that ride?”
