#214768 - 01/11/11 05:21 PM
Re: Emergency Rappeling
[Re: Tyber]
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Old Hand
Registered: 03/24/06
Posts: 900
Loc: NW NJ
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Coupla things: I would have to assume that the "rigger's belt" was originally intended as a POSITIONING device, in other words to keep you from going over the edge or our the door in the first place, not to arrest a fall or even hang in.
Industrial full-body harnesses or rear-connected waist harnesses tend to render you helpless when hanging free.
Hanging from a waist-belt only will eventually suffocate you from the pressure on your rib cage.
Fifteen feet or so of 1" tubular climbing webbing will make a safe and very servicable "swiss seat" harness. I came up with a variation with pre-tied leg loops that was even more comfortable.
A single largish pear-shaped carabiner is a suitable descending device.
Never do anything that involves hanging from a rope without a pair of prussik loops. What goes down may need to go up again.
Resist the temptation to use a knife anywhere near a rope under tension. Many rappeling accidents happen when someone tries to free a jammed descender with a knife. Likewise, keep loose clothing, gear and fingers out of the descender. Use your prussiks to unload the descender if you need to clear a jam.
Put a big knot in the end of the rope, or tie into it. I once rappeled off the end of a rope that I "knew" reached the ground.
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- Tom S.
"Never trust and engineer who doesn't carry a pocketknife."
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#214774 - 01/11/11 07:13 PM
Re: Emergency Rappeling
[Re: Tyber]
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Pooh-Bah
Registered: 04/08/02
Posts: 1821
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Attaching from the rear is not a good idea. While doing a training with a SWAT TEAM we discussed Ausie styled rappels. IN the beginning the TEAM was all about Aussie styled rappels. After we discussed things like Rappel escapes, and Figure 8 devices going "Girth hitch" or capturing the rope, or just getting stuck. By the end the team was a little more open to a new style that I learned from FIRES.
Also speaking from direct experience of having to hang in an industrial full body harness for about 30 min while being the rescued for a Mock rescue. After about 10 min of hanging my legs went numb, after 15 min of hanging I had to ascend into my secondary harness that I was wearing under the first harness.
IF YOU ARE DOING AN EMERGENCY RAPPEL DO NOT UNDER ANY CIRCUSMSTANCESS ATTACH YOURSELF OR OTHERS TO THE ROPE VIA THERE BACK. AGAIN DO NOT EVER ATTACH YOURSELF OR OTHERS BACK TO THE ROPE. I agrea, I also had to play victim in a mock rescue (rescue training), didn't hang for 30 minutes on the back attachment, but i felt nausea in a few minutes (don't do this right after lunch) and your pretty helpless. I have also seen people wearing there harness backwards to do the aussie rappel for fun, but attaching a belay device on your back is not really safe practise. Nor could they control there belay devices and need someone else to give them a firemans belay as their primary belay. All reasons to not aussie rappel. During rescue training i was taught to connect the primary connection to a victim by their rear attachment for a few specific type of rescue's, but that does not apply to normal people. Since those situations are fairly specific for height work. Besides that is rescue and not 'emergency rappeling'.
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#214776 - 01/11/11 09:22 PM
Re: Emergency Rappeling
[Re: Tyber]
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Geezer in Chief
Geezer
Registered: 08/26/06
Posts: 7705
Loc: southern Cal
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As memory serves me a lead rope is a dynamic rope, the reason I prefer keeping prusick cord that is smaller is that it is lighter and static line (aka low stretch). yes you can rappel on dynamic rope, but the stretch cna add a little "fun factor," to the rappel. I am sure that most of my rappels have been done on dynamic (lead) rope while climbing or mountaineering, the normal practice in those pastimes. Modern dynamic rope is designed to remain relatively static under loads of normal body weight, up to 300 or 400 pounds, and then become dynamic under greater stress, the kind the rope would experience in a leader fall. Rappeling on these ropes is a fairly straightforward experience, given the lengths of the typical climbing rappel, about 150 feet or so. It is different when you get into longer rappel distances, 250 feet or longer, where static ropes are best. My longest rappel was 580 feet and I was happy to use static rope, a fairly new development at the time. Static ropes are in common use in caving, where drops exceeding 200 feet are commonplace, and in rescue work, where the stiffness is essential for Z systems and the heavier loads common to that work. If you can carry only one rope, I would carry the rope rated and certified for lead climbing, as it is far more versatile. Static ropes will tear the leader apart in a significant fall; that is the point in using that sort of rope in that situation. There are no problems doing it the other way around. Needless to say, don't do any of this with rope from the hardware store. "There are bold rappelers, and there are old rapellers, but there are no old, bold rapellers..."
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Geezer in Chief
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#214787 - 01/12/11 12:38 PM
Re: Emergency Rappeling
[Re: hikermor]
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Enthusiast
Registered: 01/12/04
Posts: 265
Loc: Stafford, VA, USA
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Whenever I get around to it I will put one together. That was the first one I saw with the hook attachment.
70' of 5 mm, a couple of locking D biners, 15' or so of 1 inch tubular webbing for a swiss seat, and a pouch to carry it in is the basic setup. An ATC (small) or a figure 8 (larger) would be nice if you want a more bulky setup. I don't think I would carry a grigri or other locking descender, but that is just me.
The rope and possibly the biners/descenders would be considered disposable in this instance. Their only purpose is to get me down 5-6 floors in a burning/collapsing hotel with no other route out.
The hard part is finding a suitable anchor. If I were an apartment dweller with reinforced concrete floors, in goes a climbing bolt next to the best egress windows.
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#214788 - 01/12/11 12:41 PM
Re: Emergency Rappeling
[Re: JerryFountain]
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Enthusiast
Registered: 01/12/04
Posts: 265
Loc: Stafford, VA, USA
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A full rack was a little bit of an overstatement. With the proper training you can get by with a rope and natural anchors and still make multiple rappels. Most persons I have heard of getting stuck were higher than that, but then again I am not a SAR tech so I have to rely on mass media.
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#214790 - 01/12/11 01:21 PM
Re: Emergency Rappeling
[Re: williamlatham]
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Pooh-Bah
Registered: 04/08/02
Posts: 1821
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Whenever I get around to it I will put one together. That was the first one I saw with the hook attachment.
70' of 5 mm, a couple of locking D biners, 15' or so of 1 inch tubular webbing for a swiss seat, and a pouch to carry it in is the basic setup. An ATC (small) or a figure 8 (larger) would be nice if you want a more bulky setup. I don't think I would carry a grigri or other locking descender, but that is just me.
The rope and possibly the biners/descenders would be considered disposable in this instance. Their only purpose is to get me down 5-6 floors in a burning/collapsing hotel with no other route out.
The hard part is finding a suitable anchor. If I were an apartment dweller with reinforced concrete floors, in goes a climbing bolt next to the best egress windows. I don't see how you would control your rappel using 5mm cord, without a special belay device. Not sure if you can get a munter in a D-carabiner using 5mm cord, but i'm not sure you would even want to. A munter uses rope to rope friction to control the decent. Not sure how 5mm cord would hold that kind of abuse. A standard ATC or a Figure of eight does not give nearly enough friction to hold you with 5mm. A grigri is just useless with that cord diameter. Having less safety margin might be acceptable in an emergency, but i think this setup will just cause you to hit the deck hard. Before even trying such thing, please also look for the emergency exit or wait for the FD if you are not in direct danger.
Edited by Tjin (01/12/11 01:27 PM)
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#214794 - 01/12/11 02:05 PM
Re: Emergency Rappeling
[Re: Tjin]
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Sheriff
Enthusiast
Registered: 04/27/09
Posts: 304
Loc: ST. Paul MN
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I don't see how you would control your rappel using 5mm cord, without a special belay device. Not sure if you can get a munter in a D-carabiner using 5mm cord, but i'm not sure you would even want to. A munter uses rope to rope friction to control the decent. Not sure how 5mm cord would hold that kind of abuse.
A standard ATC or a Figure of eight does not give nearly enough friction to hold you with 5mm. A grigri is just useless with that cord diameter.
Having less safety margin might be acceptable in an emergency, but i think this setup will just cause you to hit the deck hard. Before even trying such thing, please also look for the emergency exit or wait for the FD if you are not in direct danger.
Tjin: You can take 5mm rope and double warp and triple wrap the figure 8 device and that will give you the friction, also if you are truly desprerate for friction you can twist the rope before captureing the "neck" of the figure 8. Also as memory serves me, I have herd of a supper small figure 8 device that was given to military parchuters that was designed to get them down from places that they may get caught up in. From my understanding, if a parachuter gets hung up in a tree, they can use this figure 8 device, and use either the cord they have in the chute, or that they keep on them. to rappel down to the ground. I need to be clear, I have only heard this, I have never seen this. Also there is nothing that says you can't flip the figure 8 around and use the smaller side to control the rope, and the bigger side to clip into your harness. They also now make mini non locking carabiners. I have about 6 of them and they are fun to use and very practical. before you scoff, they are as stong if not stronger than the full sized ones, the only difrence is that they are not good at handeling mutiple lines, or a lot of rope.
Edited by Tyber (01/12/11 02:05 PM)
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#214801 - 01/12/11 03:06 PM
Re: Emergency Rappeling
[Re: hikermor]
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Sheriff
Enthusiast
Registered: 04/27/09
Posts: 304
Loc: ST. Paul MN
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For fun I just looked up 5 and 6 mill cordage.
5 mill is rated at 5Kilonewtons (about 1,000 pounds) 6 mill cord is rated at 6.8 kilonewtons (about 1,400 pounds)
A kilonewton is 224.8 For simplicity and safty I always calculate a kilonewton at 220 pounds.
Before we go to much further, we need to also look at the knots in the system.
the average knot takes aobut 30% of the strength of the rope. The best knot is the one you can avoid using, seriously! here is an exaple.
lets say you have to rappel a short 50 foot drop. As luck would have it you have your handy-dandy 120 foot long 6 mill cord, a couple of locking Carabiners, a sit harness and a figure 8 device. The area is wooded and there is a solid 10inch diamater pine tree.
the best way to attach to that tree is to take wrap the rope around the tree at about head height, keeping the midle of the rope on the back side of the tree. simply doing a gian U shape with the legs of the "U" facing down. this way you can recover your rope when you get to the bottom.
If you fancier, wrap the tree twice with the center of the rope pointing towrds the direction you are going. this way there will be one full wrap around the tree. But be aware that you wil have to pull very hard to get the rope back.
Now belive it or not, by simply wraping the rope around the tree you keep 100% of the ropes strength, untill you hit you belay device. then you start to loose about 30%. Simple math says that 30% of 1,400 pounds is about 420 pounds so you are rappeling with a remaing 1,000 pounds of strength. Since this is my fantisy we will assume my weight wich is *clears throat* 280 so I would be just under ad 4:1 safty ratio. NOT the best, but safer than flying on a plane (comercial air lines are at 1:1 last I knew) FYI, when doing SAR we like to see a 10:1 or 15:1 ratio.
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#214803 - 01/12/11 03:17 PM
Re: Emergency Rappeling
[Re: hikermor]
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Addict
Registered: 12/06/07
Posts: 418
Loc: St. Petersburg, Florida
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Tyber,
Some of the 6.5 to 7.5 mm one use fire rescue rope (My last was 7.0 mm) is in the 4000 to 5000 pound catagory. Although small diameter standard rope might work in an emergency, I would not carry it for that use. I have carried 7 mm for stabilizing personnel on a steep trail, especially when carrying a litter. It would not be my choice if I were on vertical rock.
I don't know where you got your information on commercial air lines, but they are FAR from a 1:1 safety factor.
Respectfully,
Jerry
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