Mechanical rescue belay for 10mm rope?

Mechanical rescue belay for 10mm rope?

Putting two belay devices with assisted braking through their paces

We tested rescue belays (belay devices with assisted braking) as they would function as part of a two-rope system for lightweight back-country rescue.

Out in the real world of the backcountry, you often don’t have dry clean conditions. So not only did we undertake drop testing with a brand new dry rope we also field tested inside a muddy, wet cave with 40 lowers and raises on both devices.

Features

These are the features we were looking for in the mechanical belay device:

• Works with a 10mm static/semi-static rope – as the mid-range rope diameter
• Dynamic performance 200kg load – 1m drop on 3m of rope with less than 10kN* of force and 1m extension. (*Note: We considered 15kN of force too high for lightweight systems so settled on 10kN as a maximum.)
• Anti-panic handle feature – as a hands-free element for the belay line
• Adequate lowering for 80kg loads – a share of a 200kg rescue load
• Lightweight – under 500gms
• Hardwearing – can take a bit of punishment
• Operation in harsh environments – opening/closing, loading/unloading the rope
• Available – stocked locally
• Affordably priced – around the $250 mark is ideal so that you can have more than one in your team gear cache

Overview of the devices

We looked at two, the Petzl Grigri+ and the Edelrid Eddy, as they were readily available throughout New Zealand and came in at a reasonable price (around the $240 to $270 retail range).  It is worth noting that both devices were not designed specifically for rope rescue and use with semi-static or static rope. They are intended for belay in outdoor and indoor climbing with dynamic rope.

Petzl Grigri+

According to the manufacturer, the ‘Grigri+ is an assisted braking device designed for climbers, in both indoor and outdoor climbing. It can be used with all single ropes (optimized for 8.9 to 10.5 mm diameter) and is suited for intensive use. The reduction handle offers exceptional descent control. Two usage modes to choose from, depending on need: top-rope belay or lead belay. The top-rope belay mode and the anti-panic handle make for a more comfortable belay, making the Grigri+ particularly suitable for learning.’

• Weight: 200 g
• Rope compatibility: 8.5 and 11 mm in diameter
• Certifications: CE EN 15151, UIAA

Edelrid Eddy

According to the manufacturer, the ‘Eddy is an easy-to-operate semi-automatic belay device with assisted braking and maximum safety for sport and indoor climbing. A controlled descent with an emergency brake system eliminates the “panic pull” syndrome. Large lowering lever to ensure controlled descents. Simple and safe, easy to thread and logical operation.’

• Weight: 360g
• Rope compatibility: 9.0 – 11.0 mm in diameter
• Certification: EN 15151-1

Baseline testing

We used a rescue belay test of a 1m drop on 3m of rope with less than 10kN of force and 1m extension.

Drop Test data 100kg

We drop tested the belay devices with a load that is common to cave rescue, alpine rescue, and other backcountry rescue teams – 100kg. It was good to prove them in a way that they are typically used and allowed us to make a comparison to drop test data for 200kg.

Grigri+

Result: A peak force average of 6.20kN and an average extension of 53mm. The rope was in good condition, and the device could lower the load after the test.
Recommendation: Suitable as a rescue belay for one person loads.

Eddy

Result: A peak force average of 5.45kN and an average extension of 203mm. The rope was in good condition, and the device could lower the load after the test.
Recommendation: Suitable as a rescue belay for one person loads.

Drop Test data 200kg

We drop tested the belay devices with a load that is less common to backcountry rescue teams – 200kg.

Grigri+

Result: With a peak force average of 9.35kN and an average extension of 435mm. The device could lower the load after the test.
Recommendation: Suitable as a rescue belay for two-person loads.

Eddy

Result: With a peak force average of 5.67kN and an average extension of 978mm. The device could lower the load after the test.
Recommendation: Suitable as a rescue belay for two-person loads.

For more in-depth information and analysis see the post Let’s lighten the load

Use in a cave environment

By Chris Whitehouse

After some real use in a cave, it’s good to see the pros and cons of these devices. We used 10mm Donaghys rope (Response polyester abseiling braid) that was wet and muddy.

We did about 40 lowers and raises on the Grigri+ and Eddy with single person loads. Without a doubt, both devices are fantastic for belaying people as well as being simple and effective.

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Grigri+

Operation: Easy to open, close and load the rope.

Lowering: Lowering with the Grigri+ plus is difficult as the anti-panic feature keeps kicking in, making it difficult to get a smooth lower even with a redirect carabiner.

Hardwearing: In the cave environment, this device wears well.

Eddy

Operation: Difficult when your hands are wet and muddy – the button is fiddly.

Lowering: Lowering with the Eddy is difficult as the anti-panic feature keeps kicking in, making it difficult to get a smooth lower even with a redirect carabiner.

Hardwearing: In the cave environment, this device does not wear well. The face becomes pitted and starts to rust.

Comparison of the two belay devices

	Grigri+	Eddy
Works with a semi-static or static 10mm rope	Yes	Yes
Dynamic performance 100kg – 1m drop on 3m rope	Pass Extension 53mm Peak force 6.2kN	Pass Extension 203mm Peak force 5.45kN
Dynamic performance 200kg – 1m drop on 3m rope	Pass Extension 435mm Peak force 9.35kN	Pass Extension 978mm Peak force 5.67kN
Anti-panic	Yes	Yes
Adequate lowering 80kgs – Muddy, wet cave environment with redirect carabiner	Difficult – hard to find the sweet spot with the anti-panic	Difficult – hard to find the sweet spot with the anti-panic
Lightweight	Yes – 200gms	Yes – 360gms
Hardwearing – 40 raises and lowers in a cave	No major visible signs of wear	Did wear out quickly in the cave environment
Operation in harsh environments – cave	Simple	Difficult – button was fiddly
Available	Yes	Yes
Affordably priced	Yes	Yes

Conclusions

What about lowering?

1. Considering we were working with cavers who mostly use raising systems, the lowering feature is not such a big deal. The anti-panic seemed to be the issue.
2. The Grigri+ has an override of the anti-panic. You can keep lowering by continuing to pull the handle after the anti-panic has kicked in without having to reset. The manufacturer labels it for ‘exceptional use’ only (reference: Technical notice GRIGRI PLUS page 5).
3. These devices are not going to be for long lowers. Consider using tandem Prusiks pre-tensioned with a friction device. For more information on pre-tensioning see the post How effective is a friction device in front of Tandem Prusiks?

Which device?

1. Both devices passed the dynamic performance test, however, had opposite results:
   • Grigri+: Lower extension with a higher force.
   • Eddy: Higher extension with a lower force.
2. Going forward, the Grigri+ is the device we will take into further trials and testing. It has better all-around performance in the features we were looking for.

from the team at Over the Edge Rescue

Grant