Z-Rig?

[fergus]

What is a Z-rig? How do you rig one? What is it good for?

None of my CSR courses covered the z-rig, but I've noticed a lot of people talking about it. I feel like I'm missing out on something...

Thanks!

[SFDchief]

I could be wrong but I believe a Z-Rig is nothing more than a 4 to 1 hauling system. There are one's on the market as a kit. It could also be "home made". It consists of rope, a single pulley, a double pulley an ascender and a few biners.

When done, it would look something like this.

http://www.cmcrescue.com/cmcrescue/assets/dept_images/2304.jpg

[dfd3dfd3]

A z-rig isnt a 4:1 system it is a 3:1 system. What sfdchief pictured is (i dont know if this is a nation wide accepted term) a haul-safe. A haul-safe is a 4:1 which is pictured, a Z-rig is a 3:1. Its just another name for a 3:1 pulley system. A basic Z-rig wold consist of: 1 pulley, 1 ascender, 1 gri-gri, 1 caribener, and rope. And also an anchor strap and a "sky hook" carabiner to attach your gri-gri to an anchor poiint. Itll be hard to explain it here without showing u or a picture but ill give it a shot. easiest way to explain it is to first lay your rope out in a z pattern or an S configuration so u have 2 bends in the rope, on one side will be your running part of your rope then there is 2 bends then your working end. The working end is the part that you will hook the victim too and the running end is the end you will pull on. On the first bend on your working part of the rope place your Gri-Gri which is attached to an anchor point(if u dont know what a gri-gri it is a cam device where u can lower and raise that locks itself for fall arrest) So the gri-gri is at the first bend on the sencond bend u will have your pulley with a carabiner and also you will attach your ascender onto your working part of the line. This is the point where u gain your mech advantage. That is your basic Z-rig setup, hopefully it wasnt too confusing.

[dfd3dfd3]

Here is a picture of a Z-rig set up on this page
http://www.draftlight.net/lifeonaline/contents.html

[fergus]

Thanks! That helps a great deal.
One more question: Can I use a prusik instead of the ascender?

[NJTF1Bowman]

Originally posted by fergus
Thanks! That helps a great deal.
One more question: Can I use a prusik instead of the ascender?

Yes you can but use two, this will back the first one up

[resqtek]

A single prussik is acceptable. People will use only one ascender rated at anywhere from 2500lbs to 6000lbs but they feel the need to back up a prussik. This usually results from a misunderstanding of how tandem prussiks in a belay system work. A common mistake is to think that the two prussiks share the load. What actually happens is that the short prussik grabs first and begins to slip at about 8kn or 1800lbs. As the prussik slips the load is applied to the longer prussik until the load is brought to a halt and a large majority of the load, if not all, is hanging from the one prussik. The use of two prussiks is not to double the strength, it is to give more nylon to melt through before total failure. Single strand strength of most 8mm accessory cord is about 3500lbs. The strength of a prussik is a debatable issue but most figures are around 6000lbs. A haul system is a working system and should not see shock loading as a belay system would. If you are going to apply 5000 to 6000lbs of force to your haul system there is something seriously wrong. If you are overloading your system the prussik slipping will also give you a warning at about 8kn or 1800lbs. I have always used single prussiks in haul systems and most of the teams I know of do the same.

[MtnRsq]

If your CSR course isn't covering some of these (basic) rigging set-ups - what are they covering? It may be time for a new CSR course.......

You need good hands-on instruction and continuous refreshing/practice to do this well. 2:1s (c-rig)3:1s (z-rig), 4:1s, compound variations, single rope/main & belay/parallel systems, ascenders/prussiks, vertical/horizontal litter configurations, etc. all are tools to be applied as appropriate in real live rescues.

If they aren't covering this in training - you will NOT be able to put it together on an incident without a lot of luck.

Sorry......too much caffeine leads to venting that is probably unwarranted.

Check out the source below for more pictures/diagrams:

http://www.basarc.org/papers/roperescue/RopeRescue2002.pdf

It is rope-rescue specific (vs. CSR) but should help.

[806]

u will also need a safety on the working end of the rope. u will need 2 beaners 1 break & a rope.the break will be after the other break closer to the load.try to keep the rope close to the other one because when u release the rope to make another pull it will pull the main line in that direction.

[hwoods]

If you use a prusik, remember, you will have to have someone to "mind" the prusik, and keep it from binding. As you add things such as this, you will need more people to help "mind" the system, to avoid problems. Stay Safe....

[resqtek]

That is what prussik minding pulleys are for.

[MrFreeze]

Like resqtek said, the single prussik as a rope grab is fine, and better than a mechanical rope grab. Where you will use a tandem would be back at your anchor for a progress-capture/safety mechanism. I never say never, but you can be very confident in a tandem prussik safety. There is a group in Canada that tests equipment, not officially sanctioned, they just go out and break stuff. They filmed a 600# load falling 1 ft. onto 3 M of rope with different belay devices. 7 MM cord isn't much, but it caught that load with no slippage at all. Much less slippage than the poor bastard trying to stop it with a munter...

I'll echo the sentiment of if they aren't teaching you hauling/MA/raising systems in your CSR class, find a different class!

The z-rig. It's not just for rope rescue anymore. Mmmmmm.

Zach

[Lewiston2Capt]

I will agree with Mr. Freeze. The way I was taught to put together a Z-Rig uses three prussics total. 1 at the working end of the rope and two at the (first bend) anchor point. This allows you to reset your system in the event that you cant get your anchor far enough away to make the raise in a single haul. The tandem prussics work the same way Mr. Freeze described for the belay line.

[hwoods]

Thanks for mentioning Prusik Minding Pulleys. I did not forget about them, I just assumed that if someone was trying to build a system without ascenders, they would probably not have the pulleys either. Which brings us to the next rule....Don't Assume. Because, when I assume I make an ***/u/me and I shouldn't do that.:o:o Stay Safe....

[SCSESATech]

I though you need a person to mind the prusik to take up slack in a haul system(Z-rig attach to a main line), and if you reverse the system into a lowering system you still need a person to allow the rope to go threw the prusik.

[resqtek]

If your haul system is piggybacked onto the mainline then yes you will need someone to pull the mainline slack through a prussik. Then when you go back into lowering mode you can remove the prussik so it does not need to be minded. Another way to do this is to attach a rescuescender to the mainline close to the edge which is attached to the anchor with an anchor rope. Attach a bungee cord to the ascender and stake it into the ground towards the edge. The bungee will reset the ascender for you. The only time I will use a seperate haul system is if the distance to raise the load is short like in a pick off where you simply need to create slack in the victims system in order to disconnect him. In this case I simply haul the 2-3 feet and don't worry about the slack in the mainline because I always have a belay line which is being minded. When the victims system is disconnected, I lower the load back onto the rack with the haul system, remove the haul and resume lowering. If I am going to raise the load over a greater distance I will build the haul system out of the mainline. When you are ready to raise you place a load release hitch beside the brake rack and attach a prussik minding pulley and a prussik onto the mainline ahead of the rack(build your LRH so that the length is slightly longer than the brake rack or whatever descender you use). Clip the PMP and prussik into the carabiner at the end of the LRH and lower on the rack until the load is on the prussik, at which point you can untie the rack. Add another pulley and prussik to reate a 3:1. If you need to go back to lowering after you haul, you simply let the capture prussik take the load, remove the travelling pulley and prussik, and load the rack. When the rack is loaded you let out slack with the load release hitch to transfer the load to the rack. Remove the PMP and prussik and resume lowering. It sounds like alot but once you try it a couple times it is very slick.

[dfd3dfd3]

What we use is a Gri-Gri at the anchor point. This eliminates the need for a load release strap and having to switch over to lower. You can raise and lower with your Gri-Gri all you have to do is release the pulley to lower.

[resqtek]

DFD3, I really like that technique aswell but we use 12.5mm (1/2 in) rope and the grigri is designed for 11mm(7/16 in). Damn NFPA!:p

[Joecirelli]

We've been playing with a mechanical belay device available through Traverse Rescue. The unit looks like a modified pulley, and allows a very easy belay. It also includes a load release, eliminating the need for the load release strap. The unit works with incredible ease, with really no strength required of the belayer. The advantage over the tandem prusiks is there is no nylon on nylon friction, making it easier on the rope. It's also ideal for CSRs in that it incorporates the pulley for a change of direction into the unit.

One of the biggest advantages is the ability to pre-rig the unit as a belay line. This eliminates an extra step in pre-set everything for the pre-packaged 4:1 system (haul safe). Now you can set the tripod up, clip on the 4:1 and belay, and you're good to go.

[resqtek]

Sounds like the 540 belay to me. How do you like it? We are using the 540 also. It is not the fix-all device that I thought it would be. It does not perform well when conditions deteriorate(mud, snow, ice).The good thing about the 540, however, is that poor peformance will not result in injury. It will just slow things down as the device tends to jam up in these conditions. We still have tandem prussiks for a backup to the device.

[bkholmes]

We have just recently tried the 540 and I also liked it alot. We are considering asking if we can get a couple. I am concerned with the problem in tough conditions, Resqtek have you tried it in all those conditions?
Joe you mentioned using the 540 in a pre rigged setup, You can use a double prussik belay and have it pre setup. It works great. I will say though if you have the man power it is a good idea to have somone mind the prussik even when using a prussik minding pulley.

[Joecirelli]

Yes, the 540 belay is the unit we have started to use. I completely agree, it is not the end all belay device, but it is another good tool to have. We have not tried it in adverse conditions yet, and appreciate the feedback on the jamming.

We've tried to pre-rig with the tandem prussik, and have been pretty successful. The 540 seems to provide an easier means of packaging (for us at least) a nice, clean looking belay. And of course, with any pre-rigged system, a thorough safety check is always completed prior to use.

[resqtek]

Yes I have used it in these conditions. Another factor you may notice is that different brands of rope will all act slightly different in the device. Some will bind in the device more than others and some will swell enough when wet to cause some grief. The great thing about the 540 is it is simple and as we all know, in the fire service, simple is good. A poor operator is not going to hurt anybody. He will just slow things down by causing it to jam up.

[Joecirelli]

Resqtek,

I've noticed the effects the different brands of rope has on the 540. For example, Sterling rope is a little softer and more pliable than PMI. I've noticed it "slip" a little on the 540 before binding, whereas the PMI locks in right away.

I like the feel of the Sterling rope. Nice and bendable.

[PrinterRescue]

I agree with Joe. The biggest performance issue with the 540 is with the brand of rope. I have just retired my PMI ropes and have replaced them with several lengths of BlueWater, Sterling, and New England ropes. I was just about to clip my 540s together and use them as a boat anchor when I purchased the new ropes and discovered that the 540 really does work. Even with the new rope, if they get wet, the 540 becomes a monster again.

My team has taken a liking to the Petzl I'D large for single person belay work. It seems to work much smoother. Any comments on the I'D?

[bkholmes]

I am not familar with the I'D tell me more about it. My concern would be that as rescuers our team always bases everything on a 2 person load.

[resqtek]

I have never used the ID but a few people I know have done all kinds of work with it. It can be used to control a two person load for descent and belay. One of the concerns mentioned was that the device has some plastic components which, if broken, could be disastrous. There are generally two kinds of people with two different opinions about this device. There are the the idealists who feel that all devices need to be completely idiot proof and indestructible. They tend to shy away from the ID because of the questionability of its function as an unconditional belay. Then there are the realists who feel that proper training is better than supposed idiot proof devices. "Sometimes in order to make an operation idiot proof, you must remove the idiot from the operation." These people love the ID for its versatility. Like I said I have not used the ID but I would like to get my hands on one to do some tests of my own.

[SWIFTH20RESQ]

FOLKS LETS REMEMBER SOMETHING.. ITS A LOT EASIER AND CHEEPER TO USE PRUSIK CORD THAN ASENDERS, ALSO EASIER ON THE ROPE. BOTH WORK BUT PEOPLE ARE TOLD OVER AND OVER TO BACK UP, BACK UP, AND BACK UP, WHICH IS A GOOD THING!!!!!!! BUT LOOK AT ALL THE RESCUE TEAMS IN AUSTRAILIA THEY USE THE LEAST AMOUNT TO GET THE JOB DONE AND IT WORKS.

SAFE EVERYONE

[FFDigger]

This post has had alot of talk about prussiks. Do you like the use of accenders (gibbs) or prussik cords? My shift seems to be split on which is better (easy of operation/safety).
Digger

[resqtek]

I prefer to use prussiks. For the price of one ascender you can purchase a lot of accessory cord. The other good feature of a prussik is that it will slip on the rope at about 8kn(1800lbs) which helps to let you know if you are overloading your system. People will pay money to put shock absorbers at their anchors for this purpose when a prussik instead of an ascender will do the job for much cheaper. Ascenders are however very easy to attach and detach from the system so it all comes down to the application you will be using them for. For me, the versatility and economy of the prussik wins.