Canyon Rope Rescue Testing 2021
In February 2019, a team of people from the NZ Canyoning Association got together for a weekend to discuss setting up CanyonSAR for New Zealand (as a specialist discipline under New Zealand Land SAR).
As part of this weekend, we discussed and practised rope rescue in the canyoning context with training as a focus.
Out of this discussion and practice came:
- The types of rope rescues we were likely to do?
- Who are the rescuers, what is their experience level and how many are likely to be on a team?
- The techniques we are likely to use are based on the types of rescue.
- The equipment used based on what canyoners have with them is flexible for all the techniques.
- Based on risk assessment in a canyon context, the critical rescue principles include the types of rope rescues, the rescuers, techniques, and equipment.
In October 2019, we undertook initial testing before rolling out Canyon Rescue courses throughout New Zealand. After the courses, there were more questions and a process of filling in the knowledge gaps. Over the rest of 2019, 2020 and 2021, we undertook several more testing rounds to confirm the suitability further and define the edges of the system we were using.
Overall, 220 tests were undertaken with over 400m of rope and many devices destroyed.
We had funding supported by New Zealand Land Search and Rescue Training Limited and the New Zealand Canyoning Association (NZCA) project support.
Objectives
The objectives of this testing were to:
- To confirm the combination of the current equipment and techniques used have a sufficient safety margin.
- To provide reference information for rescuers and instructors to give confidence in the systems used.
Methods and Materials
Methods
General setup methods
- New rope, webbing and cord were used for the testing.
- All mechanical devices tested were new. After each test, inspected and, if not damaged, reused for the next test.
- All knots, bends and hitches had hand tension with all strands pulled tight.
Slow pull testing
- The location was Aspiring Safety, 1/6 Burdale Street, Riccarton, Christchurch, New Zealand. https://www.aspiring.co.nz/
- Vertical testbed 1.6m, Electronic Universal Testing Machine, Model WDW-100, Maximum Test Force 50kN, 60Hz, Jinan Chuanbai Instrument Equipment Co Ltd
Slow pull testing
- The location was Aspiring Safety, 1/6 Burdale Street, Riccarton, Christchurch, New Zealand. https://www.aspiring.co.nz/
- Vertical testbed 1.6m, Electronic Universal Testing Machine, Model WDW-100, Maximum Test Force 50kN, 60Hz, Jinan Chuanbai Instrument Equipment Co Ltd
Friction testing
Testing was undertaken at Aspiring Safety vertical testbed, as detailed above.
Each test recorded:
- The First slip is thumb/finger holding.
- Limiting friction is max one gloved dominant hand holding the rope.
- The glove used was Razor X 500 (pictured below).
Drop testing
- Each testing series records the drop tests set up (see Appendix 1-5 of the report).
- The drop testing occurred at Over the Edge Rescue, 55 Mckenzie Street, Geraldine, New Zealand. https://overtheedgerescue.com
- Testing used Rock Exotica Load Cells. Fast mode: 500 samples/second, MBS: 36 kN, Max Reading: 20 kN, Accuracy: +/- 2%, Certification: CE. https://www.rockexotica.com/enforcer-load-cell
- Test mass contained in 2 x 70 litre PVC bags (Aspiring Safety) filled with five bags of 20kgs of gravel. The test mass is secured into each bag, so it can’t shift during testing. To stop any swinging, the bags are attached at the base when testing with a 200kg mass.
- The load release is a three-ring device (Access Gear, see below), resulting in a smooth drop.
- Single and two rope systems were tested in lowering mode (load capture in behind with lowering device in front) and raising mode (load capture only).
In general, a drop test was a 200kg mass 1m drop on 3m of rope with the ideal of less than 1m additional travel and less than 12kN of force. Other drop tests were undertaken and are detailed in Appendix 1-5 of the test report.
Materials tested
Kordas 10mm Dana rope
- Static elongation: 3.8% (150kgs)
- Weight: 63 g/m
- Materials: Core/Sheath – Nylon/ Nylon
- Breaking strength: 27kN
- Manufacturer: www.sacidkordas.com
- Standards: EN 1891:1998, type A
PMI 10mm classic sport rope
- Static elongation: 2% (140kgs)
- Weight: 66 g/m
- Materials: Core/Sheath – Nylon/ Nylon
- Breaking strength: 27kN
- Manufacturer: PMI – www.pmirope.com
- Standards: CI 1801 static rope
PMI 8mm accessory cord
- Materials: Core/Sheath – Nylon/Nylon
- Breaking strength: 14.3kN
- Manufacturer: PMI – www.pmirope.com
- Standards: EN 564 Accessory Cord
Edelrid 25mm tubular webbing
- Brand/Model: Edelrid/X-Tube
- Weight: 43 g/m
- Materials: Nylon
- Breaking strength: 20kN
- Manufacturer: www.edelrid.de
- CE marking: 1019
Aspiring 16mm tubular webbing
- Brand/Model: Aspiring/Tubular webbing
- Weight: 34 g/m
- Materials: Nylon
- Breaking strength: 12.5kN
- Brand: Aspiring Safety – www.aspiring.co.nz
- Standards: Complies with EN 565
CT Dynamic 8.2mm Rope Sling (sewn)
- Elongation: 35 %
- Weight: 46 g/m
- Materials: Nylon/Nylon
- Breaking strength: 22kN
- Rope manufacturer: CT 8.1mm route rope dynamic half/twin
- Sling tested to EN 566:2017
- Standards Dynamic Rope: CE 1019, EN 892:2012, UIAA
- Sling Manufacturer Aspiring Safety: aspiring.co.nz
Petzl Basic
- Rope compatibility: 8 to 11 mm
- Weight: 85 g
- Manufacturer: Petzl – www.petzl.com
- Certification(s): CE EN 567, UIAA
Petzl Micro Traxion
- Sheave type: sealed ball bearings
- Weight: 85 g
- Sheave diameter: 25 mm
- Breaking strength: 2 x 7,5 = 15 kN
- Working load: 2 x 2.5 = 5 kN
- Certification(s): CE EN 567, UIAA
- Breaking strength as progress capture: 4 kN
- Efficiency: 91 %
- Rope compatibility: 8 to 11 mm
- Manufacturer: https:/www.petzl.com
Petzl Tibloc
- Rope compatibility: 8 to 11 mm
- Weight: 35 g
- Manufacturer: https://www.petzl.com
- Certification(s): CE EN 567, UIAA
- Breaking strength as a rope grab: 4-7.6 kN (depending on rope type/diameter)
- Carabiner compatibility: all Petzl models except SPIRIT
Petzl Huit
- Material: aluminium
- Weight: 100 g
- Breaking strength: 25kN
- Manufacturer: https://www.petzl.com
- Rope compatibility: 8 to 13mm
- Working load limit: 100kg
Aspiring 8mm VT Prusik
- Breaking strength: 22kN
- Material: Kevlar/Polyester sheath, Dyneema core
- Standards: EN 566:2017, ITCC 2.2.22
- Manufacturer: aspiring.co.nz
BlueWater 7mm VT Prusik
- Breaking strength: 22.6kN Basket
- Material: Technora sheath, Nylon core
- Manufacturer: BlueWater Ropes
BlueWater 8mm VT Prusik
- Breaking strength: 29.5kN Basket
- Material: Technora sheath, Nylon core
- Manufacturer: BlueWater Ropes
Results
Kordas 10mm Dana
Slow pull tests (100mm/minute)
- Figure eight on a bight knot, 19.53kN (72%), broke at the knot
- Alpine butterfly knot, 18.19kN (67%), broke at the knot
- Bowline knot, 15.94kN (59%), broke at the knot
- Figure eight rethread bend, 16.37kN (60%), broke at the bend
Figure 8 on a bight
Alpine butterfly
Bowline
Figure 8 rethread bend
- Bluewater 8mm VT 6-on-1 Prusik, 18.02kN, first slip 11.85kN, several major slips, some melting of the sheath, kept slipping.
- Bluewater 8mm VT 5-on-1 Prusik, 10.82kN, first slip 9.27kN, then kept slipping.
- Bluewater 7mm VT 6-on-1 Prusik, 16.10kN, first slip 13.39kN, several major slips, then stripped sheath of 10mm rope.
- Petzl Shunt single rope, 3.04kN, 3, first slip 2.5kN then kept slipping, no damage to rope.
6on1 8mm BW VT
5on1 8mm BW VT
6on1 7mm BW VT
Shunt 10mm single rope
- Petzl Shunt two 10mm ropes, 6.89kN, didn’t slip, ropes came out of the device (spread open), damaged sheath on both ropes 50% cam side
- Petzl Micro Traxion, 5.76kN, stripped sheath of the rope
- Petzl Tibloc, 7.64kN, stripped the sheath of the rope
- Petzl Basic, 6.35kN, stripped sheath of the rope
- Biner block, 16.31kN (60%), broke the rope at the 8mm rapide
- Munter mule overhand, 15.35kN (57%), broke at the rope at the first cross of the Munter
- Figure-8 device block v3, 16.12kN (60%), broke the rope at the 8mm rapide
- Figure-8 device in front of 8mm VT Prusik 6-on-1, 17.33kN, broke(1) and bent(2) small eye of the Petzl Huit figure-8 device
Biner block
Munter mule overhand
Figure-8 device block
Figure-8 device testing
Friction tests (100mm/minute)
First slip = rope held between index finger and thumb
Limiting friction = max rope held with one gloved hand
| Items tested | First Slip | Limiting friction | Comment |
|---|---|---|---|
| Figure-8 device canyon style low friction | 0.31 | 0.61 | 1 test, max 1 gloved hand |
| Figure-8 device canyon style high friction | 0.81 | 1.32 | 1 test, max 1 gloved hand |
| Figure-8 device canyon style low friction + redirect carabiner | 0.4 | 1.21 | 1 test, max 1 gloved hand |
| Figure-8 device canyon style high friction + redirect carabiner | 1.02 | 2.32 | 1 test, max 1 gloved hand |
Drop tests (200kg) single rope 1m drop 3m of rope
| Items tested | Av. kN | # Tests | Comment |
|---|---|---|---|
| Figure-8 device low friction in front of 8mm BlueWater 6-on-1 VT Prusik | 10.01 | 3 | Caught load, 8.5-24cm slip at Figure-8, 1-2cm slip at Prusik, Prusik releasable |
| 8mm BlueWater 6-on-1 VT Prusik | 8.02 | 3 | Caught load, slipped 17-88.5cm at Prusik, Prusik fused |
| Figure-8 device low friction in front of 7mm BlueWater 6-on-1 VT Prusik | 10.3 | 3 | Caught load, 13.5-16cm slip at Figure-8, 1-1.5cm slip at Prusik, Prusik releasable |
| 7mm BlueWater 6-on-1 VT Prusik | 8.17 | 3 | Caught load, slipped 19-67cm at Prusik, Prusik fused |
| 8mm BlueWater 5-on-1 VT Prusik | 6.95 | 3 | Caught load, slipped 34.5-107cm at Prusik, Prusik fused |
| Petzl Micro Traxion | 6.22 | 2 | (#1) Caught load , slipped 99cm, stripped sheath. (#2) Load hit the ground, cut rope |
Drop tests (200kg) single rope 1.5m drop 3m of rope
| Items tested | Av. kN | # Tests | Comment |
|---|---|---|---|
| 8mm BlueWater 6-on-1 VT Prusik | 8.45 | 3 | Caught load, slipped 20-78.5cm at Prusik, Prusik fused |
Drop tests (200kg) two rope 1m drop 3m of rope
| Items tested | Av. kN | # Tests | Comment |
|---|---|---|---|
| Figure-8 device low friction in front of 8mm BlueWater 6-on-1 VT Prusik | R1 = 5.91, R2 = 5.39, T = 11.30 | 3 | R1: Caught load, 2cm slip at Prusik, Prusik releasable, 12cm slip at device. R2: Caught load, 1cm slip at Prusik, Prusik releasable, 12cm slip at device. |
| 8mm BlueWater 6-on-1 VT Prusik | R1 = 5.33, R2 = 5.17, T = 10.50 | 3 | R1: Caught load, 2cm slip at Prusik, Prusik releasable. R2: Caught load, 2cm slip at Prusik, Prusik releasable. |
| 7mm BlueWater 6-on-1 VT Prusik | R1 = 5.62, R2 = 5.39, T = 11.01 | 3 | R1: Caught load, 2.5cm slip at Prusik, Prusik releasable. R2: Caught load, 2.5cm slip at Prusik, Prusik releasable. |
| 8mm BlueWater 5-on-1 VT Prusik | R1 = 5.39, R2 = 5.55, T = 10.94 | 3 | R1: Caught load, 2cm slip at Prusik, Prusik fused. R2: Caught load, 2cm slip at Prusik, Prusik fused. |
| Petzl Micro Traxion | R1 = 6.00, R2 = 5.84, T = 11.84 | 1 | R1: Caught load, 18.5cm slip at Micro Traxion, stripped sheath, 20cm bunching before device. R2: Caught load, 18.5cm slip at Micro Traxion, stripped sheath, 20cm bunching before device |
Drop tests (200kg) single rope 0m drop 3m of rope
| Items tested | Av. kN | # Tests | Comment |
|---|---|---|---|
| 8mm BlueWater 6-on-1 VT Prusik, start two ropes, 50% on tension on each rope, released onto 1 rope | 2.77 | 3 | Caught load. 0.5-1.0cm slip. Prusik releasable. |
| 8mm BlueWater 6-on-1 VT Prusik, start two ropes, 100% on tension on 1 rope, released onto other rope | 4.01 | 3 | Caught load. 0.5-1.0cm slip. Prusik releasable. |
PMI 10mm Classic Sport
Slow pull testing (100mm/minute)
| Items tested | Avg. kN | # Tests | Comment |
|---|---|---|---|
| Figure-8 on a bight knot | 18.17 (67%) | 3 | Broke at the knot |
| Alpine butterfly knot | 19.43 (72%) | 3 | Broke at the knot |
| Bowline knot | 17.52 (65%) | 3 | Broke at the knot |
| Figure-8 rethread bend | 18.13 (67%) | 3 | Broke at the bend |
| Aspiring 8mm VT 6-on-1 Prusik | 17.7 | 3 | First slip 12.89kN, slipped 5-6cm, glazed sheath, broke fig-8 knot |
| Aspiring 8mm VT 5-on-1 Prusik | 15.42 | 3 | First slip 9.87kN, slipped and regripped, kept on slipping |
| Petzl Shunt single rope | 2.31 | 3 | First slip 2.17kN, kept on slipping |
| Petzl Shunt double rope | 5.99 | 1 | Didn’t slip, both ropes came out of device as it spread open, damaged sheath both ropes 50% on the cam side. |
| Petzl Micro Traxion | 5.9 | 3 | Stripped sheath of rope |
| Petzl Tibloc | 7.02 | 3 | Stripped sheath of rope |
| Petzl Basic ascender | 6 | 3 | Stripped rope sheath (2) and device broke (1) |
| Biner block | 15.59 (58%) | 3 | Broke the rope at the 8mm rapide |
Friction tests
| Items tested | First Slip kN | Limiting friction kN | Comment |
|---|---|---|---|
| Munter / Italian | 0.54 | 1.41 | 1 test, max 1 gloved hand |
| Double Munter / Italian | 1.37 | 3.85 | 1 test, max 1 gloved hand |
| Munter / Italian + redirect carabiner | 0.69 | 1.29 | 1 test, max 1 gloved hand |
| Double Munter / Italian + redirect carabiner | 1.55 | 4.08 | 1 test, max 1 gloved hand |
Drop tests (200kg) Single Rope 1m drop 3m of rope
| Items tested | Av. kN | # Tests | Comment |
|---|---|---|---|
| Figure-8 device low friction in front of 8mm Aspiring 6-on-1 Schwabisch VT Prusik | 12.14 | 3 | Caught load, 16-20cm slip at Figure-8, 1-3cm slip at Prusik, Prusik releasable |
| 8mm Aspiring 6-on-1 Schwabisch VT Prusik | 10.3 | 3 | Caught load, slipped 9-17cm at Prusik, Prusik fused |
| 8mm Aspiring 5-on-1 Schwabisch VT Prusik | 8.69 | 3 | Caught load, slipped 35.5-82cm at Prusik, Prusik fused |
Drop tests (200kg) Two Ropes 1m drop 3m of rope
| Items tested | Av. kN | # Tests | Comment |
|---|---|---|---|
| Figure-8 device low friction in front of 8mm Aspiring 6-on-1 Schwabisch VT Prusik | R1 = 6.62 | 1 | R1: Caught load, 1cm slip at Prusik, Prusik releasable, 13cm slip at device. |
| R2 = 5.90 | R2: Caught load, 1cm slip at Prusik, Prusik releasable, 12.5cm slip at device. | ||
| 8mm Aspiring 6-on-1 Schwabisch VT Prusik | R1 = 6.93 | 3 | R1: Caught load, 4.5cm slip at Prusik, Prusik fused. |
| R2 = 5.79 | R2: Caught load, 3cm slip at Prusik, Prusik fused. | ||
| 8mm Aspiring 5-on-1 Schwabisch VT Prusik | R1 = 6.32 | 1 | R1: Caught load, 10cm slip at Prusik, Prusik fused. |
| R2 = 6.30 | R2: Caught load, 10cm slip at Prusik, Prusik fused. |
PMI 8mm Accessory Cord
Slow pull tests (100mm/minute)
| Items tested | Average kN | # Tests | Comment |
|---|---|---|---|
| Loop: double fisherman’s bend | 23.82 | 3 | Broke at the bend |
| Loop: figure-8 rethread bend | 20.34 | 3 | Broke at the 12mm pin and bend |
| Wrap 3 pull 2 on a 30mm pin | 35.3 | 3 | Broke 1 strand at the carabiner |
| Wrap 2 pull 2 on a 30mm pin | 29.54 | 3 | Broke 1 strand at the carabiner |
| 2-point anchor, overhand knot, 2 strands clipped, 1 carabiner | 24.47 | 3 | Broke at fixed overhand, top side 1 strand, leg without bend |
| 2-point anchor floating focal, overhand limiting knots, 1 strand clipped, 1 carabiner | 18.36 | 3 | Broke at limiting overhand, bottom side, leg without bend |
| 2-point anchor floating focal, overhand limiting knots, 2 strand clipped, 2 carabiners | 29.61 | 3 | Broke at limiting overhand, bottom and top, leg without bend |
Drop tests (200kg)
| Items tested | Av. kN | # Tests | Comment |
|---|---|---|---|
| 2-point anchor fixed focal, overhand knot, 2 strands clipped, 1 carabiner, 0cm drop | 2.79 | 3 | Dropped onto the side without bend |
| 2.59 | 3 | Dropped onto the side with bend | |
| 2-point anchor floating focal, overhand limiting knots, 1 strand clipped, 1 carabiner, 10cm drop | 5.45 | 3 | Dropped onto the side without bend |
| 4.96 | 3 | Dropped onto the side with bend |
Edelrid 25mm Tubular Webbing
Slow pull tests (100mm/minute)
| Items tested | Average kN | # tests | Comment |
|---|---|---|---|
| Loop: Tape/Overhand rethread bend | 27.83 | 3 | Broke at tape/overhand bend |
| Wrap 3 pull 2 on a 30mm pin | 40.08 | 3 | Broke 1 strand at the carabiner |
| Wrap 2 pull 2 on a 30mm pin | 37.93 | 3 | Broke 1 strand at the carabiner |
| 2-point anchor fixed focal, overhand knot, 2 strands clipped, 1 carabiner | 36.23 | 3 | Broke at overhand knot single strand and steel carabiner |
CT 8.2mm Dynamic Rope
Slow pull tests (100mm/minute)
| Items tested | Average kN | # tests | Comment |
|---|---|---|---|
| Loop: Sewn | 22.47 | 3 | Broke at stitching |
| 2-point anchor fixed focal, overhand knot, 2 strands clipped, 1 carabiner | 30.24 | 3 | Broke at fixed overhand, both strands, bottom leg |
| 2-point anchor floating focal, overhand limiting knots, 1 strand clipped, 1 carabiner | 18.07 | 3 | Broke at limiting overhand knot, 1 strand, on the sewn leg |
| 2-point anchor floating focal, overhand limiting knots, 2 strand clipped, 2 carabiner | 31.53 | 3 | Broke at limiting overhand, both strands, on the sewn leg |
Drop tests (200kg)
| Items tested | Av. kN | # Tests | Comment |
|---|---|---|---|
| 2-point anchor fixed focal, overhand knot, 2 strands clipped, 1 carabiner, 0cm drop | 2.45 | 3 | Dropped onto the side without stitching |
| 2.39 | 3 | Dropped onto the side with stitching | |
| 2-point anchor floating focal, overhand limiting knots, 1 strand clipped, 1 carabiner, 10cm drop | 3.9 | 3 | Dropped onto the side without stitching |
| 4.19 | 3 | Dropped onto the side with stitching |
Discussion
Kordas 10mm Dana
Slow pull tests
Knots, bends and hitches:
The knots (figure-8 and alpine butterfly) were over 18kN and suitable for canyon rescue. The bowline was under 16kN and is not suitable; however, it is not used.
The figure-8 rethread bend had a lower breaking strength (16.5kN) than the figure-8 knot (19.53kN). It is suitable for canyon rescue joining Kordas Dana rescue ropes as there is no better alternative.
Rope grabs:
The 8mm BlueWater VT Prusik 5-on-1 hitch first slipped at 9kN and then kept slipping at 11kN. The 8mm BlueWater VT Prusik 6-on-1 hitch slipped at 12kN and broke either the rope or kept slipping at 18kN. The 7mm BlueWater VT Prusik 6-on-1 hitch slipped at 13kN and stripped the sheath of the 10mm rope at 16kN. All variations are suitable for canyon rescue as a progress capture and rope grab.
The Petzl Shunt was tested as a pulley system rope grab for a single rope (3kN) and double rope (7kN). The single rope Shunt is preferred as it slides without damaging the 10mm rope.
The Petzl Basic (6kN) and Tibloc (7.5kN) were tested as a pulley system rope grab. The Basic is not recommended as it broke half in 2 out of the 3 tests and held 1.5kN less (on average) than the Tibloc. The Tibloc, used as a rope grab on half of a two-rope system (100kg), is suitable for rescue.
The Petzl Micro Traxion (6kN) was tested as a pulley system load capture. Due to the potential of dynamic loading for this part of the system, it was unsuitable.
Canyon rope blocks:
Standard canyoning rope blocking and releasable methods, including the biner block (16kN), Munter mule overhand (15kN) and the Figure-8 device block v3 (16kN), were tested. These blocks could end up in the rescue system, so it was good to have some data to understand any limitations. The figure-8 device block was changed (v3) not to slip and instead broke the rope.
Lowering device:
The Figure-8 device (Petzl Huit) in Canyon mode friction, on an extension, with a 6-on-1 8mm VT behind (rescue lowering mode) broke at 17kN, which is close to 18kN and the breaking strength of the knots. Suitable for all rescue-lowering situations.
Friction tests
The Figure-8 device (Petzl Huit) in Canyon mode friction, on an extension, with a redirect, had friction over 1kN for half a two-rope system and could be converted to 2kN+. Therefore this device and method had suitable friction for their use in rescue.
Drop tests
1m drop on 3m of rope, 200kg
Drop tests were undertaken to represent two people plus equipment with a short section of rope in play (1m drop on 3m of rope, 200kg).
Single Rope: The average force for a 7/8mm BlueWater VT Prusik 5/6-on-1 Prusik was 10kN in lowering mode (2cm slip) and 7-8kN in raising mode (83cm slip). All the VT tested are suitable for a progress capture and have a high margin.
Single Rope: The average force for a Petzl Micro Traxion was 6kN in raising mode (99cm slip or cut the rope) and is not suitable as a progress capture as it stripped the sheath or cut the rope.
Two Ropes: The average force for a 7/8mm BlueWater VT Prusik 5/6-on-1 Prusik was 5.5kN per rope (11kN total) in lowering mode (2cm slip) and 5.25kN per rope (10.50kN total) in raising mode. All the VT/Figure-8 devices tested are suitable and have a high margin.
Note: A failure on double ropes will increase the combined force on the anchor system as there is less stretch. Use caution where systems share anchors (some or all) between both ropes and are not independent.
Two Ropes: The average force for a Petzl Micro Traxion was 6kN per rope (12kN total) in raising mode (18.5cm slip, stripped sheath) and is unsuitable for progress capture.
0m drop on 3m of rope, 200kg
Drop tests were undertaken to represent two people plus equipment with ropes in normal operating raising mode, with 50% on each rope (50/50) or 100% on one and 0% on the other (100/0).
The average force for an 8mm BlueWater VT Prusik 6-on-1 Prusik 50/50 was 2.77kN in raising mode (.5-1cm slip). On average, about 1.5x the load.
The average force for an 8mm BlueWater VT Prusik 6-on-1 Prusik 100/0 was 4.01kN in raising mode (.5-1cm slip). On average, about 2x the load.
1.5m drop on 3m of rope, 200kg
Drop tests were undertaken to represent two people plus equipment with ropes, a worst-case short amount of rope in play (1.5m drop on 3m of rope, 200kg).
The average force for an 8mm BlueWater VT Prusik 6-on-1 Prusik was 8.45kN in raising mode (20-78.5cm slip).
On average, around 0.5kN more than the equivalent 1m drop on a 3m rope drop test and the same slip.
The VT Prusik performed well, considering the extreme nature of the test.
PMI 10mm Classic Sport
Slow pull tests
The knots (figure-8 and alpine butterfly) were over 18kN and suitable for canyon rescue. The bowline was under 18kN; however, it is not used by canyon rescue.
The figure-8 rethread bend has a breaking strength of over 18kN and is suitable for canyon rescue for joining rescue ropes.
The 8mm Aspiring VT Prusik 6-on-1 hitch slipped at 13kN and broke the rope at the figure-8 at 17.5kN. The 8mm BlueWater VT Prusik 5on1 hitch slipped at 10kN and 15.5kN. All variations are suitable for canyon rescue as a progress capture and rope grab.
The Petzl Shunt was tested as a pulley system rope grab for a single rope (2kN) and double rope (6kN). The single rope Shunt is preferred as it slides without damaging the 10mm rope.
The Petzl Basic (6kN) and Tibloc (7kN) were tested as a pulley system rope grab. The Basic is not recommended as it broke half in 1 out of the 3 tests and held 1kN less (on average) than the Tibloc.
The Petzl Micro Traxion (6kN) was tested as a pulley system load capture. Due to the potential of dynamic loading for this part of the system, it was unsuitable.
Standard canyoning rope-blocking methods were tested, including the biner block (15.5kN). These may end up in the rescue system, so it was good to have some data to understand any limitations.
Friction tests
The Munter/Italian hitch, on an extension, with a redirect, had friction over 1kN for half a two-rope system. Therefore this device and method had suitable friction for their use in rescue.
Drop tests
All drop tests were undertaken to represent two people plus equipment with a short section of rope in play (1m drop on 3m of rope, 200kg).
Single rope: The average force for an 8mm Aspiring VT Prusik 6on1 Prusik was 12kN in lowering mode (2cm slip) and 10kN in raising mode (13.5cm slip). The average force for an 8mm Aspiring VT Prusik 5on1 Prusik was 8.5kN in lowering mode (51.5cm slip). All the VT tests held are suitable and have a high margin.
Note: The PMI rope has nearly half the stretch of the Kordas rope, so it has a higher (1-2kN) max arrest force.
Two ropes: The average force for an 8mm Aspiring VT Prusik 6on1 Prusik was 5.5kN per rope (11kN total) in lowering mode (2cm slip) and 6.25kN per rope (12.5kN total) in raising mode (4cm slip). The average force for an 8mm Aspiring VT Prusik 5on1 Prusik was 6.25kN per rope (12.5kN total) in raising mode (10cm slip). All the VT tested are suitable and have a high margin.
Note: A failure on double ropes will increase the combined force on the anchor system as there is less stretch. Use caution where systems share anchors (some or all) between both ropes and are not independent.
PMI 8mm Accessory Cord
Slow pull tests
The loops tested (figure-8 rethread and double fisherman’s) were over 20kN and suitable for rescue use.
The W3P2 and W2P2 tested well over 20kN (30-35kN) and are suitable for use for rescue.
Floating focal point testing of a single strand is suitable for one side of a rescue system (18kN) or as part of a multi-point anchor. With two strands clipped, on average, tested over 29kN and are suitable for both sides of a rescue system.
On average, a two-point fixed focus anchor is over 24kN and is suitable for rescue.
Drop tests
Drop testing a fixed focal by failing one side gave results of, on average, 2.5kN.
Drop testing a floating focal by failing one side gave results of, on average, 5kN. The limiter overhands do the job well of decreasing the impact force fall after a single anchor failure. Used in the proper context, it is suitable for rescue.
Aspiring 25mm Tubular Tape
Slow pull tests
The loop was tested with a tape bend over 27kN and is suitable for rescue.
The W3P2 and W2P2 tested well over 20kN (37-40kN) and are suitable for rescue.
A two-point fixed focus anchor is well over 20kN (36kN) and is suitable for rescue.
CT 8.2mm Dynamic Rope
Slow pull tests
The sewn loop, on average, tested over 24kN and is suitable for rescue.
On average, a two-point fixed focus anchor tested over 30kN and is suitable for rescue.
On average, a two-point floating focus anchor with a single strand with limiter overhands tested over 18kN is suitable for rescue on one side of a two-rope system.
A two-point floating focus anchor with two strands with limiter overhands, on average, tested over 30kN and is suitable for rescue on both sides of a two-rope system.
Drop tests
Drop testing a fixed focal by failing one side gave results of, on average, 2.5kN.
Drop testing a floating focal by failing one side gave results of, on average, 4kN. The limiter overhands do the job well of decreasing the impact force fall after a single anchor failure. Used in the proper context, it is suitable for rescue.
Conclusions
We have tested canyoners’ equipment to understand what works and what doesn’t in the rescue context.
A greater understanding of the system and the safety margin in normal operating mode and worst-case failure has been gained.
Testing gives confidence that the systems used are going to work effectively. This confidence is essential as many other things are going on in an actual rescue. It frees up our thinking up to concentrate on other vital elements.
This testing has focused on parts of the system failing. However, the opposite action is the best focus in the field – working together to prevent failure.
Check out the Canyon Rescue Testing Report 2021 below.
Grant
from Over the Edge Rescue.
