Review: Petzl RAD System

I wrote an update for this review that takes into account some recent changes including an update in Petzl’s published strength of the RAD line from 8kN to 12kN.  For this updated review click here.  The original post is below.

Original post:

Petzl recently released the RAD (Rescue And Decent) system which is basically a lightweight rope kit that skiers can take with them into mountains to deal potential issues such as rappelling cliff bands, undertaking crevasse or cliff rescue and roping up when crossing glaciers.  While kits of this nature have been available to Guides for some time Petzl has made the RAD system available to everyone who wants a light-weight rope kit.  This is great as it’s more likely that people will actually take the emergency equipment with them into the mountains if it’s light… as long as it works well!  So, how light-weight is the RAD system?  When does it work well, when doesn’t it?  To evaluate the RAD system we did what we do best: abused it!

So let’s start with what’s in the RAD system:

  • RAD Line (basically a 30m x 6mm static cord)
  • Micro Traxion (a low-friction, simple and effective pulley/progress capture device)
  • Tibloc (super simple rope grab)
  • 3 x Attache 3D Carabiners (I love these things)
  • 120cm dyneema sling
  • A great stuff sac w. ice screw sleeve

While each of these items is available on its own the kit puts them into a convenient package that, when combined with a harness, creates a good basic light-weight rope kit.  That being said, there are a few extra items that could also be considered depending on the intended use, expected terrain, etc. but i’ll talk about that later.  Lets focus on the RAD line first as it’s new and central to this kit.

BON21951
The 6mm RAD line on top with an 8mm dynamic glacier rope and a 9.5mm rock climbing rope. The RAD line is significantly smaller and lighter.

The RAD line is a 6mm static cord that is made from high modulus polyethylene (also knows as Spectra® or Dyneema®), aramid (a heat resistant synthetic fiber) and polypropylene.  When compared to 8mm dynamic half ropes which are often used for glacier travel this represents a weight savings of almost 50% (22g/m versus 37-42g/m for 8mm+/- dynamic half ropes), huge right!  Given it’s small diameter and light weight the RAD line still has a relatively high breaking strength of 12kN (earlier documentation stated 8kN but this was in reference to the what the testing required, the actual strength is 12).  It is of note that this 12kN strength is dropped to about 6kN as soon as a knot is tied in the line (it’s too bad eyes aren’t stitched into the ends!), a force that could be achieved by shock loading the system if not careful given the static nature of the RAD line.

When we started playing with the RAD system the first thing that we noticed is that there’s no middle mark on the RAD line, not surprising given that high modulus polyethylene and aramid doesn’t dye well.  However, this can be a bit of pain in the ass when rappelling.  Speaking of rappelling on the RAD line, we tried a Reverso as well as an Italian Hitch (Munter) and found that there’s not enough friction to use the Reverso safely with the typical set-up.  However, by doubling up on the carabiners at the belay device the friction is increased to where things were much more reasonable.  The Italian Hitch also worked very well, using just a single carabiner of course.  Because the RAD line is quite thin it can be hard to hang onto with the brake hand when rappelling and a back-up should be considered.

It’s hard to compare static and dynamic ropes (which are often used in glacier travel) as dynamic ropes stretch to absorb energy and are not rated by breaking strength. So let’s look at the pro’s and con’s of the static RAD line versus a dynamic half rope instead.  When rappelling or undertaking a rescue a static line is great as there’s very little stretch to pull out the rope making it much more efficient.  On the down side the force of a fall is not reduced by the stretch (lower force over a longer period of time as the rope stretches) which means that the system experiences a high force over a short duration in a fall scenario.  Some research that Petzl has done on this topic indicates that there is a slightly better chance of arresting a crevasse fall with a static rope as the load is more predictable, however falls on rock or during a rescue could be catastrophic on a static rope.  Anyway, what I’m saying is that there are benefits to the static RAD line but that there are also trade-offs to consider.

RAD3to1
3:1 Mechanical advantage system using all the gear in the kit: sling on the anchor, carabiner on the person getting rescued, MicroTraxion, Tibloc and 2 carabiners in the haul system.
RopeAscent
Rope ascent system using a sling for a leg loop.

Petzl has created a great basic rescue kit with the RAD system.  However, as mentioned before, it’s not necessarily a complete set-up depending on what you’re doing and so should be looked at as great place to start from when building a kit for a given trip.

One thing that was in the back of my mind when testing out the RAD system for rescue is that by having a static system there is less room for error as any type of shock load would be catastrophic.  Like it says on the bag “Expert Use Only”, if you plan to use the system it’s worth taking the time to practice with it.

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Some of the gear that’s not part of the RAD kit that could be considered and a ski mountaineering harness… hard to do much without a harness.  We should have a review of Petzl’s new ski mountaineering harness up soon.

Speaking of training, it should also be noted that it takes training and practice to become safe and efficient at glacier travel, crevasse rescue, rope decent and ascent, etc. Purchasing this kit and/or other equipment is a good starting point but without the expertise to use it, not much of a benefit.  If you are new to these activities and want to learn more the IFMGA is a great place to find your country’s guiding association and through them certified trainers, or just email me and I can help out.

Pros:      This kit is very light, simple, expandable and efficient.

Cons:     No middle mark on the RAD line.

Overall:   If you’re looking for a versatile light-weight rope rescue kit this thing is great!  However, be aware of the limitations and you will likely want to customize the kit with a bit more (or different) gear depending on the trip or expected use.

Petzl supplied a sample of the RAD kit to use and abuse but of course this did not influence our review in any way.

2 thoughts on “Review: Petzl RAD System

  1. Cody says:

    Your 5:1 is a 3:1 and your 3:1 is a 2:1. The first pulley redirects force, the second is what gives the advantage. Easy to remember that you can’t have more advantage than there are pulleys 😉

    • Monte says:

      Cody,

      I think that you may be mistaken in your Z-system advantage calculations. The 3:1 shown in the review has gained extra advantage by tethering the pulley to the loaded rope before going up through the anchored pulley ending up with 3 loaded lines and a 3:1 advantage. If I were to connect another ‘biner to the anchor to redirect the load so I am pulling down there would be the 3 pulleys that you are looking for. The 5:1 shown is simply a 2:1 on-top of the 3:1. Ropebook.com has some great descriptions of how to read advantage: http://www.ropebook.com/information/pulley-systems.

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