ABS/AvaLung hybrid TR

[Toby]

I got one of mntlion's ABS packs a while back. I also liked the idea of the AvaLung concept, but preferred the packs to the AvaLung II. ABS is burial prevention, AvaLung is burial mitigation. I wanted the best of both worlds so I set out to retrofit AvaLung II internals to my ABS pack to create a Frankensteinian hybrid.

I hinted at my ideas at the end of an earlier thread. I'd gotten together some simple materials:



Unfortunately, the white hose that I initially thought was great (crushproof, cutproof) really sucked (heavy and tasted of rubber). I found some other hose that fit the bill, although has some shortcomings. It crushes but rebounds to its original shape, although it's pretty resistant to crushing. It's hard plastic but thin and cuts easily with a box cutter so I'll keep an eye on its abrasion resistance. I'm going to replace parts of it with another AvaLung hose when it arrives (thanks LeeLau). Anyway, I started cutting, gluing and messing around and this is what I came up with.

Inside the pack:



You can see the working part of the AvaLung. In practice it's pretty simple - two low-pressure non-return valves in a black box. Initially I had the black box oriented about 135° clockwise so the air intake was through the pack next to the box. I only did this because the original AvaLung configuration has no air intake hose - it comes directly into the box. The original orientation was going to be a tight fit though, so I changed my mind. Unfortunately I'd already put a breathing vent through the pack and 36-hour epoxied it in place so I had to cut that out, scrape/pry off the epoxy and sew a patch on. You can see the patch in the shoulder view next to where the breathing hose comes out of the pack:



The breathing hose comes out of the pack through a hole designed for hydration bladder hoses and routes through a piece of material I cannibalised from the AvaLung II harness to make it look sweet. I stitched and epoxied the material onto a loose bit of material on the shoulder strap (the matching piece of material on the other strap is what routes the ABS trigger cable). Cable ties hold the breathing hose onto a 3/4" hose-to-hose connection which is then connected to the standard AvaLung breathing hose.

Here's another view from the top showing the intake vent and a different view of the material hose sleeve:



Although flexible, the black hose is kinda stiff so I need to cable tie it to the shoulder strap. If I do that it sits nicely in a perfect position. With the mouthpiece in you can move your head in all directions with no restriction. First I want to cover those existing cable ties with amalgamating tape though.

Lastly, the bottom view:



In the internal view you can see I ran the outlet hose from the AvaLung valve box down a probe/shovel handle sleeve. It exits out the bottom of the pack. I debated whether to go the bottom or out the bottom side. My concern with this location is I just hope it doesn't get blocked when I set the pack down in the snow between laps.

So I'm pretty happy with the results. It breathes like it's supposed to. I went outside the parameters of the original AvaLung II by extending the mouth-black box by about 8". I also ran an intake hose that's about 6" with a 90° kink. The outlet hose is about the same length as the original. The materials are pretty light, much less than the original AvaLung II (with all the harness material). Unfortunately the ABS pack weighs a tonne though .

I still have to tidy up some things:

• cable ties on the hoses-black box connections
• amalgamating tape on all the cable ties
• sewing to tighten up the routing on the breathing tube sleeve and outlet hose sleeve
• I was considering putting a snorkel mouthpiece on instead of the AvaLung one but I'm yet to find one that's light yet crushproof. I think the snorkel mouthpiece would be much easier to hold in the mouth in an actual slide (not that I'm anticipating being in one). Unfortunately it'd spoil the sweet factory look.

My regrets are:

• cutting the hole that required the patch. At the time I wanted to stay close to the AvaLung original configuration but decided it unnecessary. In the end I preferred the intake/outlet as far away from each other as possible.
• putting in the intake vent after 12hrs before a 2nd coat of 36hr epoxy on the black box had dried. You can see in the internal picture where the epoxy has cracked while I messed around twisting and flexing hoses. It's non-structural but I'll probably build it up again later anyway. I should've been more patient.

All my materials came from boat shops. They had just the right combination of materials to do this project. The black hose has an internal diameter of 3/4", which is exactly what the connections on the AvaLung box are = airtightness without O-rings.

To finish off, BDEL couldn't condone what I'm doing or help out with supplies or advice or anything. I understand their position (avoiding legal liability) but I would've preferred to do this with their help. In particular I would've preferred to get a long length of their blue accordion hose because it seems perfect for the application. The only thing it sucks at is connections since it's two hoses in one (a white internal hose and a blue external hose) and the inside hose is too small for all the male connections. Oh well.

My position is if ever the shit hit the fan (touch wood), if I did screw this up and I'm breathing CO2 I'm no worse off than if I didn't have a modified AvaLung anyway. But the project's pretty simple anyway - there's not much to go wrong, it's just simple plumbing. In fact, you could do this yourself without an AvaLung. One boat shop had 1/2" and 3/4" non-return valves that you could make a homemade AvaLung black box with. However, they're designed for water applications so the pressure required is a bit high (I tested them by breathing through them and the resistance is noticeable). Find the right valves and you'd be in business.

[JTrue]

Great work man, looks like it should work the same as the original as long as all the parts you used hold up.

[summit]

cool beans!

[Core Shot]

nice work.
I would just add that epoxy is not the best glue for fabric or any other flexible material.
It tends to crack and peel.

Perhaps an adhesive silicone or "Dymonic" brand adhesive would be better.

[Tony]

Excellent work! Now it needs to be tested in real conditions. Any plans for a simulated burial?

Just out of curiosity, how much the whole (empty) backpack weights now?

Core Shot, check your message box.

[mntlion]

nice work. I'm tempted to keep the last one I have and do that with it...

[Toby]

I would just add that epoxy is not the best glue for fabric or any other flexible material.
It tends to crack and peel.

Perhaps an adhesive silicone or "Dymonic" brand adhesive would be better.

Yeah, I had the epoxy so decided to use it. There won't be much flexing except on the shoulder strap hose sleeve but I'd prefer a flexible glue there for sure. The only reason I cracked the epoxy on the black box was because I had to put a shit ton of force to press the connections together on the intake vent.

Now it needs to be tested in real conditions. Any plans for a simulated burial?

Nope. If I do screw up a snowpack evaluation the ABS is to prevent me getting buried . The AvaLung is there as a worser-than-worst-case scenario.

Just out of curiosity, how much the whole (empty) backpack weights now?

The ABS pack weighs approx 7lb. The AvaLung materials wouldn't be more than a few oz.

[Toby]

Post-test update: I need to refine the idea. The blue hose over the shoulder got a lot of holes in it because I carry my skis on my right shoulder. Even though I didn't carry them much and was fairly careful to carry them next to the hose not on the hose it trashed the hose. The holes in the blue hose didn't compromise the system because I guess the internal white hose is what carries the air. Still, it needs replacing. Also on the shoulder, where the black hose attaches to the white hose, the black section just separated one day, almost as though it was cut or faulty. A very even, clean separation between accordion sections. That kinda scared me because I thought that hose was great. So I need lots and lots of blue hose because I'd like all the plumbing to use it and this time I'll be more careful with the shoulder carrying. I got some from LeeLau already from an old AvaLung but I really want a small reel of it. Black Diamond can't help me. I already asked about this in another thread with no luck. I guess I'll keep looking.

When the system was working, it was working great though. I really liked the whole system/idea.

[Dawn Patrol]

Just a thought, by increasing the length of the hose (to the valve), you are also increasing the amount of exhaled air you are rebreathing. Make the hose long enough, and you'll be rebreathing 100% stale air. I like the idea though.

[Arty50]

Pretty cool. One suggestion though, replace that screen with something else. The holes on there look kinda big. My avalung has a sort of breathable mesh over the exit instead.

[under the radar]

Great idea, really impressed with how clean this came out.

I've seen flexible tubing that looks really close to the blue stuff in home depot or lowes, I think it was in the dryer section. Also, hard to tell where you are using epoxy, but maybe hose clamps would work?

[Toby]

Someone correct me if I am wrong, but I thought the point of the avalung was to redirect your exhaled air behind you, not as an "in hole." I imagined that you would breathe through your nose and exhale through the mouth piece. Thus, you don't rebreathe the air in the tube (mostly).

Nope, you breathe in and out through the tube. The black box has two one-way valves to direct the in- and out-air to different places. If you breathed in through the nose and out through the tube you'd only need a single piece of tubing, no expensive AvaLung black valve box.

Pretty cool. One suggestion though, replace that screen with something else. The holes on there look kinda big. My avalung has a sort of breathable mesh over the exit instead.

I asked BD for one of those mesh patches. No luck. The mesh is big. It's designed as a throwaway primary filter for a bilge pump. I liked it because it's bomber (my first thought was to use insect screening). In practice it did get snow/ice in it from putting my pack down and at times I thought it would be blocked but every time I tested it air got through as though there was nothing there.

I've seen flexible tubing that looks really close to the blue stuff in home depot or lowes, I think it was in the dryer section. Also, hard to tell where you are using epoxy, but maybe hose clamps would work?

I still want the blue/white AvaLung hose. That's going to be the best I think.

The only place I used epoxy was in a particularly difficult connection. It needed epoxy. All other joints the hose connections were tight enough that they needed nothing. I used cable ties then wrapped self-amalgamating tape around the cable tie to make sure there were no sharp edges.

[smalls]

I asked BD for one of those mesh patches. No luck. The mesh is big. It's designed as a throwaway primary filter for a bilge pump. I liked it because it's bomber (my first thought was to use insect screening). In practice it did get snow/ice in it from putting my pack down and at times I thought it would be blocked but every time I tested it air got through as though there was nothing there.

i'd put some finer screen/mesh underneath the bomber stuff you have, so you have good protection and still keep most of the snow out.

[BambooShoot]

Nope, you breathe in and out through the tube. The black box has two one-way valves to direct the in- and out-air to different places. If you breathed in through the nose and out through the tube you'd only need a single piece of tubing, no expensive AvaLung black valve box.

speaking of which... does anyone think a simple hose to breath out would do anything? i kinda like the simplicity of a single hose that directs your exhaled co2 to a different area than where you're trying to breath in. a poor-man's avalung.

[Toby]

Sure, it'd work. As long as you remembered to breathe in your nose and out your mouth (or vice versa). No easy feat in a stressful situation I'd reckon.

[JakeS]

[QUOTE=
I still want the blue/white AvaLung hose. That's going to be the best I think.
[/QUOTE]

Hi Toby

It looks like BD has sourced these tubes from the medical air industry.
I happened to notice something similar on a machine at a Veterinary Hospital.
A little searching turned up this.

http://www.dreveterinary.com/product...roducts_id/257

The stuff I saw was the same blue as the BD stuff.
There's some here called evac hose.

http://anesthesiatechnologies.com/accessories.html

Some more searching may turn up some good supply.

Jake

[Toby]

Yeah, it seems like medical tubing. It's got two layers, so from your second link you could maybe try some of that blue 19mm corrugated tubing inside the white 22mm corrugated tubing.

My setup these days is all BD tubing. I ended up using tubing from a BD pack, an AvaLung II, and an original AvaLung I vest all sourced from various generous members on TGR. If anyone wants to do the same thing and you find cheap AvaLung I vests, those had the longest amount of tubing, the BD pack setup the 2nd longest.

The BD tubing is the best I tried because it's very strong in compression, retains its shape if it does get crushed (unless it folds or creases) and very light. The only downside is it's weak against abrasion. I got around that (hopefully) by sewing a long sheath out of butchered material for the tube that goes over the shoulder. So in the original photos I've got a short grey sheath, now it's longer than the black piece of tubing over the shoulder. I used heavy cordura from some excess ABS pack material (it came with a little hip bag or something that I had no use for so I cut that up). And I don't carry my skis on my right shoulder, which kind of sucks because I can't get used to carrying on the left.

[JakeS]

Nice
Glad you got it sorted out.
I might try it someday.

[mb2778]

this is really cool! My only concern is about the avalung performance once the ABS is inflated... Obviously you'll only need the lung if you get burried, in which case the ABS will have gone off but failed, so is there any danger of the inflated airbags covering the intake or exhaust?

Also, anyone got a spare ABS lying around they wanna sell me?

[1000-oaks]

Given the current spike in airbag sales, thought this thread would be of value. Would like to do this with a Blackjack.

Several other choices for tubing:
19mm blue and 22mm clear evacuation tubing

CPAP or BiPAPtubing

Corrugated Aerosol Tubing

Nitrous Oxide Supply Tubing

[TheDon]

Solid work, wow really

[sb]

Fantastic retrofit.

[1000-oaks]

Using a small funnel or something flared to give the exit filter screen more surface area would be a good idea, like BD does with their Avalung packs. They don't need to do this with the vest or Avalung harness because the end of the tube vents in all directions through a fine-mesh filter sock.

Would be cool if Mystery Ranch provided the Blackjack with edge-finished entrance and exit holes already in the pack, to make it really easy to swap in an Avalung.

[cliffhucker]

Given the success of airbags in bringing "avalanched" victims to the surface, It seems highly unlikely that if wearing one of these, you would be buried, and if you were, it would be due to trauma and an extremely violent avalanche in which case an avalung would be useless (possibly ripped out of your mouth, you're unconscious, or already dead.) I think the avalung is a great idea (i wear one in certain areas) but i think it is kindof an idealized tool, it would be very helpful in a situation where terrain wouldn't kill you in the midst of an avalanche.

[harpo-the-skier]

I have a much simpler system for retrofitting an Avalung II to pretty much any backpack, though certainly not as clean.

Get an Avalung 2, cut off all the straps, and attach it to your pack shoulder strap with nylon webbing/duct tape/zip ties. Make sure to back up the zipties with something else as they break in the cold. I have used this system with bigger Cilogear backpacks and they have survived 3-6 day camping trips, although I have not been burried while using the system, either voluntarily on unvoluntarily. Do a search, there was a blog post on this by someone a few years ago.