Method Exit bag and inert gas megathread

[kudaphillips]

Ok. Thank you. My other questions...

Regarding supplies - Do some have to be ordered online in the US or can you get all this locally at stores?

I see a lot of pretty high tech setups but is that necessary for success? I don't have the capacity to store or display all this stuff....I would need to hide it until the time came, maybe with exception to the nitrogen tank. Is that even feasible?

Anyone in the US with a hood or exit bag setup who I can PM?

Exit bag supplies for USA

Turkey bag - wal mart or amz
elastic - Amz or joaan fabric / micheals etc
Micropore tape - amz or Walmart
Toggle- amz or Joan fabric / micheals
Oxygen tubing - amz, Walmart, any medical supply
Regulator - amz or some big box store like Home Depot / industrial supply etc
Tank - amz or any gas supply store

All easy to hide except tank over 40cf starts to get big .

The high tech setups in my opinion aren't necessary, but you will,achieve unconsciousness/ death faster with scba or scuba …but imo , can present other problems ( many members will disagree with me )

 

[devils~advocate]

Im not sure if anyone has the CGA-347 version.....but there is an adapter to CGA-580.
Its readily available online. Its a two component adapter system for USA though.
CGA-347 ----> 347 to 1/4 adapter ----> 1/4 to CGA 580 adapter ----> CGA 580 tank

(Id be glad to share my findings. Im not sure what kind of conversation is allow in direct messages)

 

[suffering_mo]

Exit bag supplies for USA

Turkey bag - wal mart or amz
elastic - Amz or joaan fabric / micheals etc
Micropore tape - amz or Walmart
Toggle- amz or Joan fabric / micheals
Oxygen tubing - amz, Walmart, any medical supply
Regulator - amz or some big box store like Home Depot / industrial supply etc
Tank - amz or any gas supply store

All easy to hide except tank over 40cf starts to get big .

The high tech setups in my opinion aren't necessary, but you will,achieve unconsciousness/ death faster with scba or scuba …but imo , can present other problems ( many members will disagree with me )

Do you know where I might obtain a regulator or which one is best? Could someone possibly point me in a direction?

Also, could use opinions....if I don't live alone, is this method even feasible? I would only have 3 1/2 weeks to gather everything I would need also. I can leave the house to get supplies right now, except for tank but would be limited in my ability to get them out/practice, etc.

Is the tank the first thing you want to obtain?

I apologize for the questions.... there is 160 pages of information here to go through and I have limited time. Thank you for your mercy.....my physical situation is quite severe and I'm tortured 24/7 and I am getting to where I won't be able to leave my home soon.

 

[kudaphillips]

Do you know where I might obtain a regulator or which one is best? Could someone possibly point me in a direction?

Also, could use opinions....if I don't live alone, is this method even feasible? I would only have 3 1/2 weeks to gather everything I would need also. I can leave the house to get supplies right now, except for tank but would be limited in my ability to get them out/practice, etc.

Is the tank the first thing you want to obtain?

I apologize for the questions.... there is 160 pages of information here to go through and I have limited time. Thank you for your mercy.....my physical situation is quite severe and I'm tortured 24/7 and I am getting to where I won't be able to leave my home soon.

There's no recommended best regulator . I posted a reply above telling you where you can get it. Very ubiquitous online and in stores . Members will say as long as it has a flowmeter greater than 15 lpm ( nitrogen ) it's suitable . Also get one that has the quarter inch barb already on it, so it's easy to connect the oxygen tubing, no adapters needed etc. Also, check gas Monkeys thread " share your gas setups, you can see everyone's regulator choices.

If you live with other people , it's not a feasible method, unless your going to be home alone for an hour minimum. The gas is somewhat loud, others would hear it.

There's no order for what to obtain first. All supplies are incredibly easy to obtain and put together .

If In the states , firearm also easy to obtain , not even a waiting period for a shotgun . Could look into that also. The Firearm megathread is pretty good info.

 

[suffering_mo]

There's no recommended best regulator . I posted a reply above telling you where you can get it. Very ubiquitous online and in stores . Members will say as long as it has a flowmeter greater than 15 lpm, it's suitable . Also get one that has the quarter inch barb already on it, so it's easy to connect the oxygen tubing, no adapters needed etc. Also, check gas Monkeys thread " share your gas setups, you can see everyone's regulator choices.

If you live with other people , it's not a feasible method, unless your going to be home alone for an hour minimum. The gas is somewhat loud, others would hear it.

There's no order for what to obtain first. All supplies are incredibly easy to obtain and put together .

If In the states , firearm also easy to obtain , not even a waiting period for a shotgun . Could look into that also. The Firearm megathread is pretty good info.

I would have some limited time to do it alone but it's getting everything together, hiding the supplies, setting it up that is my concern. Hiding a nitrogen tank is kinda iffy but I could. Everyone on this thread seems to have a dedicated space for it, practicing, etc.

Yes, I can obtain a firearm and likely will but for many reasons (I am a woman and don't like guns, have no experience and can't practice), it is not a great method for me. It may end up being my only option in the end, however.

 

[thot88]

Is it possible to send a private message where you can order the EEBD hood. I could only find vague sources when I googled. I live in northern Europe.

 

[kudaphillips]

Is it possible to send a private message where you can order the EEBD hood. I could only find vague sources when I googled. I live in northern Europe.

Alibaba

 

[devils~advocate]

Do you know where I might obtain a regulator or which one is best? Could someone possibly point me in a direction?

Also, could use opinions....if I don't live alone, is this method even feasible? I would only have 3 1/2 weeks to gather everything I would need also. I can leave the house to get supplies right now, except for tank but would be limited in my ability to get them out/practice, etc.

Is the tank the first thing you want to obtain?

I apologize for the questions.... there is 160 pages of information here to go through and I have limited time. Thank you for your mercy.....my physical situation is quite severe and I'm tortured 24/7 and I am getting to where I won't be able to leave my home soon.

Yes like OP stated, a regulator with flowmeter greater than 15 lpm liters per minute (nitrogen). They usually come with a barb. "A" sells these. The regulator is used for Argon inert gas in welding applications. The barb is 1/4" size and one can get a hose to fit that easily at big box housegoods stores L & HD.
These regulators will have the CGA-580 connection that also works for a nitrogen tank. (This connection works for argon, CO2, nitrogen etc.)

Tank is the last thing one can get. It is obtained locally.
Making the hood looks reasonable. It will take some time to fabricate.
There are some safety type hoods available thru Chinese online sites but will need time for shipping.

Go thru the steps of fabricating a hood, doing the best care you can. Don't skip any steps. Do a good job.
In the mean time the regulator can be ordered.
OR the local places that sell the tanks will have regulators as well. Just print out photos & show the sales people.

This flowmeter shows standard cubic feet per hour (scfh)....But get the flow at least 32 scfm . This is equivalent to 15 liters per minute.
(There are online calculators do convert units)

 

[k1w1]

I would have some limited time to do it alone but it's getting everything together, hiding the supplies, setting it up that is my concern. Hiding a nitrogen tank is kinda iffy but I could. Everyone on this thread seems to have a dedicated space for it, practicing, etc.

Yes, I can obtain a firearm and likely will but for many reasons (I am a woman and don't like guns, have no experience and can't practice), it is not a great method for me. It may end up being my only option in the end, however.

Can you take a trip to Peru?

 

[kudaphillips]

Can you take a trip to Peru?

What's in Peru? Euthanasia ? Or N?

 

[Placo]

View attachment 3848

Sorry to ask again, what type of cable should I use to connect the cylinder to the bag?

 

[kudaphillips]

Sorry to ask again, what type of cable should I use to connect the cylinder to the bag?

It depends on your regulator outlet . Oxygen tubing connects to 1/4 in barb which most members use , but judging by your question, I strongly recommend rereading the explanation in beginning of this thread, if you plan to ctb , page 1

 

[devils~advocate]

It depends on your regulator outlet . Oxygen tubing connects to 1/4 in barb which most members use , but judging by your question, I strongly recommend rereading the explanation in beginning of this thread, if you plan to ctb , page 1

Yes what type of regulator do you have. Can you post a image of it? Some have barb outlets, while others use a threaded fitting.

If it is a barb outlet, then plastic tubing works fine. If you have a retail store that sells wood, nails etc...they would have this type of tubing. Take the barb to the store and ask the sales people for help. They will get you the right diameter and the banding to tighten around it.

 

[Theresnoescape]

Would something like this work?

Would something like this work?

Or this one?

 

[Kawaii_Shoujo215]

Hey guys, I have a question regarding testing a SCBA set-up with a breathing air cylinder, as was suggested by some users here. (I live in EU)

The source of gas I am using has an option for compressed air ("Druckluft/Pressluft"), but I am unsure if this is the kind that can safely be used for SCBA/SCUBA, or if SCBA/SCUBA requires the gas to be purified of potential contaminants that otherwise wouldn't be a problem (if you weren't breathing it in). After all, I don't want to risk getting compressed air meant for cleaning or for power tools into my lungs and causing damage/cancer/other problems.

Any advice? Thanks in advance.

 

[devils~advocate]

Would something like this work?

Or this one?

Im not familiar with metric international connections...but if you can get a hose attached to it, then it would work.
This is for the hood application?
Also, Im not sure if 2L is enough. We use cubic feet in the US.....a 40cf tank is about 8L.
It seems to be the consensus that at least 15 min of running time at minimum of 15L per min.
I just dont know if a 2L bottle will last that long releasing at that rate needed.

Hey guys, I have a question regarding testing a SCBA set-up with a breathing air cylinder, as was suggested by some users here. (I live in EU)

The source of gas I am using has an option for compressed air ("Druckluft/Pressluft"), but I am unsure if this is the kind that can safely be used for SCBA/SCUBA, or if SCBA/SCUBA requires the gas to be purified of potential contaminants that otherwise wouldn't be a problem (if you weren't breathing it in). After all, I don't want to risk getting compressed air meant for cleaning or for power tools into my lungs and causing damage/cancer/other problems.

Any advice? Thanks in advance.

SCBA system uses compressed air. It is meant for firefighters & keep them from breathing smoke filled outside air.
Usually the gas (in this case normal air) is at least 2200 psi (150 bar or15k kPa) ( I hope I have the conversions correct)
No the gas does not need to be purified. The gases used are Nitrogen, Helium etc. They usually are supplied in high pressures as well, so no problems.
Suppliers offer these in clean tanks, so no contaminants.
Im not sure what you are worried about with contaminants.....this is ultimately for CTB.

The SCBA system uses a regulator that brings the pressure in the tank down to about 85-130 psi (690 kPa).
This regulator is attached to the tank. Its part of the SCBA system.
Then the gas flows to a 'lung demand valve'...which is a fancy one way valve that activates on breathing demand.
This valve then allows the gas to enter the face mask.
The whole purpose is for fire fighters to breath only air from the tanks they carry & not smoke filled outside air.
But for CTB purposes, it is being utilized for a different purpose.

I will produce a tutorial using images explaining the SCBA system with parts someday.

 

[Lion_50]

My nitro cylinder valve sits at 150 bar (out of 350). Is that still enough gas/pressure for my 10L tank to cib using SCBA?

 

[Placo]

I ordered a helium tank which according to the manufacturer is 99.0% pure, it is 0.40m3.

I also ordered one of those gym backpacks that close elastically, maybe now I'm just missing a tube; or could I try to inflate the backpack like a balloon and immediately put it on my head?

 

[Theresnoescape]

Im not familiar with metric international connections...but if you can get a hose attached to it, then it would work.
This is for the hood application?
Also, Im not sure if 2L is enough. We use cubic feet in the US.....a 40cf tank is about 8L.
It seems to be the consensus that at least 15 min of running time at minimum of 15L per min.
I just dont know if a 2L bottle will last that long releasing at that rate needed.

SCBA system uses compressed air. It is meant for firefighters & keep them from breathing smoke filled outside air.
Usually the gas (in this case normal air) is at least 2200 psi (150 bar or15k kPa) ( I hope I have the conversions correct)
No the gas does not need to be purified. The gases used are Nitrogen, Helium etc. They usually are supplied in high pressures as well, so no problems.
Suppliers offer these in clean tanks, so no contaminants.
Im not sure what you are worried about with contaminants.....this is ultimately for CTB.

The SCBA system uses a regulator that brings the pressure in the tank down to about 85-130 psi (690 kPa).
This regulator is attached to the tank. Its part of the SCBA system.
Then the gas flows to a 'lung demand valve'...which is a fancy one way valve that activates on breathing demand.
This valve then allows the gas to enter the face mask.
The whole purpose is for fire fighters to breath only air from the tanks they carry & not smoke filled outside air.
But for CTB purposes, it is being utilized for a different purpose.

I will produce a tutorial using images explaining the SCBA system with parts someday.

Hi, I'll search for a larger tank, thanks for the help. I'm sure I'll have more questions.

 

[Kawaii_Shoujo215]

It is meant for firefighters & keep them from breathing smoke filled outside air.
Usually the gas (in this case normal air) is at least 2200 psi (150 bar or15k kPa) ( I hope I have the conversions correct)
No the gas does not need to be purified. The gases used are Nitrogen, Helium etc. They usually are supplied in high pressures as well, so no problems.
Suppliers offer these in clean tanks, so no contaminants.
Im not sure what you are worried about with contaminants.....this is ultimately for CTB.

The SCBA system uses a regulator that brings the pressure in the tank down to about 85-130 psi (690 kPa).
This regulator is attached to the tank. Its part of the SCBA system.
Then the gas flows to a 'lung demand valve'...which is a fancy one way valve that activates on breathing demand.
This valve then allows the gas to enter the face mask.
The whole purpose is for fire fighters to breath only air from the tanks they carry & not smoke filled outside air.
But for CTB purposes, it is being utilized for a different purpose.

I will produce a tutorial using images explaining the SCBA system with parts someday.

Thanks for the reply. I just wanted to clarify that I am well aware that nitrogen is used, as well as am quite well-versed in SCBA basics. My question was referring to testing the SCBA or, more specifically, the exhalation resistance, as well as generally getting used to the feel, doing practice runs, etc., and that I'd like to use compressed air for this testing (since nitrogen would make me pass out, with potentially leaks/problems/discomfort while exhaling, etc., which could make CTB fail or make it less comfortable, such as with SI/anxiety)).

The problem is that compressed air is used for many things (like welding, power tools, cutting, cleaning, etc.), and that there is a certification here in Europe (EN 12021) for compressed air specifically used for firefighting or scuba diving, which has had potential contaminants removed. My question was whether or not compressed air without this certification is safe to use for testing, or if it can lead to lung problems, dizziness, health problems, etc., since it may contain small traces of CO, CO2, water vapor, methane, etc.

 

[devils~advocate]

Hi, I'll search for a larger tank, thanks for the help. I'm sure I'll have more questions.

Glad to help. Im in this boat as well.
If you are in the EU you might can get the SCBA system from the source or at least locally there.

My nitro cylinder valve sits at 150 bar (out of 350). Is that still enough gas/pressure for my 10L tank to cib using SCBA?

150 bar = 2175 psi. 10L tank is about the same as a 80 cubic foot tank.
The conversions are confusing. But from what I know SCBA systems operate btwn 85-130 psi.
Now how long a tank would last at a rate that is efficient....Im not sure, here is my attempt using SCUBA method
Water Volume = 10 L
Working Pressure = 150 bar
Ideal capacity 10 ×150 ÷1.01325 = 1480 L
Z Factor =1.0263
True capacity 1480 ÷1.0263 ≈ 1440 L
Usage: (assuming 15L/min for CTB) 1440L ÷ 15L/min = 96 minutes

This is assuming that regular Air is being used. Nitrogen compressed acts differently, but I would assume not that much.
Someone will need to check the mathematics of this.

Thanks for the reply. I just wanted to clarify that I am well aware that nitrogen is used, as well as am quite well-versed in SCBA basics. My question was referring to testing the SCBA or, more specifically, the exhalation resistance, as well as generally getting used to the feel, doing practice runs, etc., and that I'd like to use compressed air for this testing (since nitrogen would make me pass out, with potentially leaks/problems/discomfort while exhaling, etc., which could make CTB fail or make it less comfortable, such as with SI/anxiety)).

The problem is that compressed air is used for many things (like welding, power tools, cutting, cleaning, etc.), and that there is a certification here in Europe (EN 12021) for compressed air specifically used for firefighting or scuba diving, which has had potential contaminants removed. My question was whether or not compressed air without this certification is safe to use for testing, or if it can lead to lung problems, dizziness, health problems, etc., since it may contain small traces of CO, CO2, water vapor, methane, etc.

Oh sorry, I didnt know you meant for Testing purposes.

I obtained the same Air tanks that are typically used with the SCBA systems for the fire fighters.
There are plenty available for purchase. If you can get one, I would recommend it. They are used only for normal air and are clean with no contaminants.
The issue I had was that in the USA, there are laws that only allow air tanks to be filled that fit some time parameters.
One is that the tank must be within 15 years of manufacturer to the day you want to fill it. The manufacture date is printed on the tanks for this purpose.
Another is that the tanks must be tested every 5 years. The testing agency will place a stamp on the tank showing that is has been tested.
In the EU it appears there is a similar requirement (I am not sure though).

But I would recommend attempting to get one of these scba air tanks and have it filled to the normal pressure with normal air.
Usually before they fill it, they can clean out the tank.

As for other types of tanks....that the risk. Usually tanks are designated for the gas they will contain.
I would think a Helium tank or CO2 tank would be fine.
They would take the valve off of the tank, clean it out with water & soap...dry it....then replace the valve...then fill with normal air to the correct pressure.

What type of tank have you acquired?

I ordered a helium tank which according to the manufacturer is 99.0% pure, it is 0.40m3.

I also ordered one of those gym backpacks that close elastically, maybe now I'm just missing a tube; or could I try to inflate the backpack like a balloon and immediately put it on my head?

(Assuming you referring to the hood method)
I think a tube that would supply a constant flow to a sealed hood would work.
the consensus is that 15L/min should work. CTB time needed at least 15 min....so 15L/min X 15 min = at least 225 L of expanded gas is needed.

 

[ClownWorld2023]

My question was whether or not compressed air without this certification is safe to use for testing, or if it can lead to lung problems, dizziness, health problems, etc., since it may contain small traces of CO, CO2, water vapor, methane, etc.

My EEBD set had a compressed air cylinder too, apparently for breathing purposes.
I tested it out, but the air was way too contaminated.
Like you could smell gasoline fumes or whatever that's emitted by air compressors normally.


I don't think the certification is that important, but you'll want clean compressed air that's filtered properly.
So compressed air straight from a regular backyard air compressor without filters won't do for this purpose.

The problem is that compressed air is used for many things (like welding, power tools, cutting, cleaning, etc.), and that there is a certification here in Europe (EN 12021) for compressed air specifically used for firefighting or scuba diving, which has had potential contaminants removed. My question was whether or not compressed air without this certification is safe to use for testing, or if it can lead to lung problems, dizziness, health problems, etc., since it may contain small traces of CO, CO2, water vapor, methane, etc.

Diving gas cylinders with regular compressed air would be suitable for this.
We're nearing summer now so you can go to any diving shop and get it refilled as often as you want.

I had the same idea previous winter, but it would have been too suspicious at the time, because most people don't go diving during the cold.

So just go to any diving shop and ask for a regular diving/breathing gas cylinder.

 

[Schmopo]

It certainly sounds that you have a flowmeter since it has a ball and indications of liters per minute.

If you have decided on eebd hood you have most of the equipment required. You just have to figure out how to mount the eebd hose onto the flowmeter since 5/8 would probably be too big. I would suggest using a 5/8 to 1/4 barb adapter with a 5/8 hose between the flowmeter and adapter.

Quick update: Upon looking at the photo now, I realised I bought the wrong adapter as both ends are 5/8. Doesn't matter much because the 5/8 hose for my cylinder only just slips in and out of the 5/8 adapter end fairly easily and using the hose clamps are not doing anything to keep it secure. What am I missing?

 

[devils~advocate]

Quick update: Upon looking at the photo now, I realised I bought the wrong adapter as both ends are 5/8. Doesn't matter much because the 5/8 hose for my cylinder only just slips in and out of the 5/8 adapter end fairly easily and using the hose clamps are not doing anything to keep it secure. What am I missing?

Can you post a photo of what you are talking about?
My suggestion is take whatever adapter you have (assumed from what you are saying that is a barb connection) and take it to the hardware store to get the right diameter plastic hose to fit it. The big box home stores have all that. The sales people can help as well.

My EEBD set had a compressed air cylinder too, apparently for breathing purposes.
I tested it out, but the air was way too contaminated.
Like you could smell gasoline fumes or whatever that's emitted by air compressors normally.


I don't think the certification is that important, but you'll want clean compressed air that's filtered properly.
So compressed air straight from a regular backyard air compressor without filters won't do for this purpose.




Diving gas cylinders with regular compressed air would be suitable for this.
We're nearing summer now so you can go to any diving shop and get it refilled as often as you want.

I had the same idea previous winter, but it would have been too suspicious at the time, because most people don't go diving during the cold.

So just go to any diving shop and ask for a regular diving/breathing gas cylinder.

Certification is important if in the USA for an air tank used for breathing. No place will fill it legally without a certification stamp.
I obtained the same tanks as made for the SCBA systems.
They have to be within a 15 year manufacture date
They also have to get a hydrostatic test. This is valid for 5 years. There are places that do all this.
I had it done and have tanks filled to 3000 psi & 2200 psi. This was done a a scuba dive shop. They will only fill if there is a stamp & manufacture date.

This is doable regardless. The tanks fit the scba systems exactly (cga-346 & 347 types) & was able to test my scba system.
I wanted to make sure the few LDVs I got, worked. One of them did not work, or I can't figure out how to keep it from leaking.

BTW, I know it was mentioned that for the cga-347 scba system there didnt seem to be a way to connect to a cga-580 nitrogen connection.
But there are simple straight forward adapters to make the cga-347 system work that I found easily. Once I get it all together, I will post a photo.

 

[Placo]

I bought one of those gym backpacks but unfortunately it lets the air through, at this point I'm wondering what I can invent for the helium without having to buy too much equipment.

I could buy the balloons and then inflate them and explode them in a plastic bag and then put it in so I'm sure there is a good percentage of helium, or inflate the bag directly with helium as if it were a balloon and then put it in, the helium should being lighter than air while CO2 is heavier so by keeping the bag in the right position I shouldn't lose large quantities before placing it.

I'm sure the bag doesn't let air pass through, I've already done experiments, one thing I wonder is if breathing helium CO2 is produced by the body anyway, I know it's produced by oxygen but if one inhales air which is mainly composed of helium and nitrogen, would it be produced anyway? So I could tie the bag tightly around my neck to prevent gas from escaping and at the same time not feel the effects of the rising CO2.

I just asked Google's AI and it responded like this:

No, your body wouldn't produce CO2 if you breathed air made mostly of helium and nitrogen. Carbon dioxide (CO2) production is a byproduct of cellular respiration, a process in which cells use oxygen (O2) to break down nutrients and generate energy.

Why oxygen is essential for cellular respiration:

1. Electron acceptance: Oxygen molecules act as the final electron acceptors in the electron transport chain, a process crucial to the production of ATP, the cell's energy molecule.
2. Concentration gradient: The difference in oxygen concentration between the inside and outside of the cell promotes its movement inward through passive diffusion, fueling cellular respiration.

In the absence of oxygen:

* Anaerobic respiration: Cells activate alternative energy production mechanisms that do not require oxygen, such as fermentative glycolysis. However, these processes produce less ATP than cellular respiration and generate byproducts such as lactic acid, which can cause muscle fatigue.
* Cell Death: Prolonged oxygen deprivation leads to cell death, as essential cellular processes cease to function.

So, if you only breathed helium and nitrogen:

* No oxygen intake: Oxygen would not be present for cellular respiration.
* No CO2 production: Cellular respiration would not occur, therefore no carbon dioxide would be produced.
* Cell Death: Cells would eventually die due to lack of oxygen and the resulting disruption of vital metabolic processes.

In summary, CO2 production is closely linked to cellular respiration, which requires oxygen. In the absence of oxygen, the body would not produce CO2, but would suffer serious consequences, including potential cell death.

Good news I'd say.

 

[ClownWorld2023]

Certification is important if in the USA for an air tank used for breathing. No place will fill it legally without a certification stamp.
I obtained the same tanks as made for the SCBA systems.
They have to be within a 15 year manufacture date
They also have to get a hydrostatic test. This is valid for 5 years. There are places that do all this.
I had it done and have tanks filled to 3000 psi & 2200 psi. This was done a a scuba dive shop. They will only fill if there is a stamp & manufacture date.

Yes the gas cylinders are all certified (or atleast, supposed to be).

I think @Kawaii_Shoujo215 was asking whether it was possible to also use compressed air gas cylinders which are not intended for breathing/diving purposes.

It should be possible as long as the cylinder's connection matches the SCBA regulator, and the compressed air is clean (you'd have to ask for this).

There are differences between the different compressed air cylinders.
I remember the diving gas cylinders here were either rated at 230 bar or 300 bar.
The prices can also vary wildly, but the 300 bar cylinders are (much) more expensive in general.

 

[annasharon]

The Regulator:

A regulator screws on to the cylinder and does two things: 1) it reduces the pressure in the cylinder to a useable level, otherwise the 2000psi tank pressure would just blow the exit bag off your head as soon as you opened the valve, and 2) it controls the rate of gas flow into the exit bag —specifically, it should release it at 15Lpm, which is the minimum adequate to carry away exhaled CO2 and fool your lungs into believing there's enough air.

The good news is that while gas cylinder sizes are not globally standardized, the cylinder valve threads are —and both N2 and Ar cylinders have the same threads (other gasses have different threads), so a regulator that fits on one cylinder will fit equally well on another.

You don't need to worry about being sure to choose a regulator that will reduce the pressure: they all do that. The flowmeter is the critical element of the regulator for our purposes.

Some regulators come with a "click adjust" flowmeter that is very simple, allowing you to dial in 15Lpm without needing to think about it. To the best of my knowledge, these are medical grade regulators; generally very good quality, but often a bit more expensive. Others here may know more about them, and where to acquire them, than I do.

A typical welding regulator will have two gauges: the tank pressure gauge (unimportant to us) and the flowmeter gauge.

A welding regulator's flowmeter gauge will be marked in either cubic feet per hour (Cfh), Lpm, or both. Some welding systems require a fairly low flow of inert gas, much lower than our necessary 15Lpm, and this low flow is most easily measured in Cfh. If you see a gauge marked only in Cfh, it probably will not work for our purpose. Look at the highest Cfh setting on the flowmeter and do the math, to be certain. If the gauge reads in Lpm, a glance should tell you whether the regulator provides the necessary 15Lpm flow.

Harbor Freight Tools offers a cheap CO2/Ar regulator (it also works for N2) with a flowmeter that shows flow in both Cfh and Lpm and goes high enough for our purposes. This is what I have.

The Hose:

The hose needs to be long enough to reach from the gas cylinder beside you, up into the exit bag on your head. I have found it easiest to lead the hose up my back and into the bag at the very back of my neck. It seems to disrupt the fit of the bag less right there.

Some regulators come with a hose that threads directly into the regulator body. Some regulators come with a hose-barb, onto which a length of soft tubing can be pressed. Some regulators come with neither.

For the first situation, just thread the hose into the regulator, tighten it with a wrench, and it's ready.

(Regardless of what type of threaded fitting is used, you do need to wrench-tighten this fitting: a lot of gas can leak out at this connection. If it is a brass fitting, you should not need teflon tape on the threads; the soft metal deforms enough when tightened to provide an adequately gas-tight connection.)

For the second situation, take the hose-barb to a hardware / home improvement store and purchase tubing that fits onto the barb. Once home from the hardware store, thread the barb into the regulator body, tighten with a wrench, and press the tube onto the barb. It should be a snug fit; if you're worried it's too loose, use a small hose clamp / jubilee clip to secure it in place. If it's a little too tight to get the hose into place, soak the end of the tube in very hot water to soften it and press it onto the barb. I used clear vinyl tubing. Aquarium tubing should work. Surgical tubing may not; I don't know for sure.

For the third situation, you'll need a hose-barb fitting (typically brass) that threads into the regulator body. Take the entire regulator to the hardware store and ask someone to help you fit it with a hose barb. Then proceed as for the second situation.

Cover story: as with purchasing the gas cylinder, you're using N2 for brewing, or Ar for filling partial paint cans. Why Ar? because it's heavier than air and settles down onto the paint surface inside the can. For extra confidence that they won't ask inconvenient questions, you're doing it for your father, or your brother, and you don't know why they want it for their paint locker, they just said to get a hose barb and six feet of tubing…

The Exit Bag:

There are several videos on YouTube detailing construction of exit bags. I strongly recommend watching them. That's how I learned.

The short version of what you want is a turkey roasting bag —available in the supermarket, in with the zip-locks and cling wrap— with an elastic drawcord worked into a turned hem, and a cord-lock to adjust the drawcord's tension.

I used 3/8" elastic cord. I purchased both it and the cord lock at a sewing and crafts store (JoAnn's).

To construct the turned hem you'll need micropore (surgical) tape, available at a pharmacy in the first aid section. It's the right tape to use because it will reliably stick to the material of the bag itself. Sometimes it isn't labeled as "micropore." Ask a clerk if you can't find it.

Cover story: you were asked to re-stock the family first aid kit with micropore tape and you don't recognize any of the brands available.

Using an elastic drawcord is important: it needs to fit snugly around your neck, but not seal tightly. It must still be flexible enough for the flow of inert gas, lightly pressurizing the exit bag, to push past the elastic and flush away the CO2 you're exhaling. Don't use a non-elastic drawcord or do something like duct tape the bag to your neck; you don't want to create a seal, just a restriction.

Hi, they are asking me at the shop "which hose do I need". What should I say?

Hi, they are asking me at the shop "which hose do I need". What should I say?

What length should the hose be and which kind of hose? They are asking at the shop

 

[devils~advocate]

Hi, they are asking me at the shop "which hose do I need". What should I say?

What length should the hose be and which kind of hose? They are asking at the shop

I guess what regulator are you using? The type it is makes a difference. Some have a barb that plastic (polyethylene vinyl) tubing fits over.
My first thoughts are that the clear vinyl type of tubing would work fine.
Length...I'd say at least 4-5 ft (120-150cm)

 

[devils~advocate]

Normal human breaths are about 0.5L at 12 times per minute.
Thats about 6L per minute. It doesnt seem like much.

Divers using scuba gear typically consume about 15 - 25L per minute.

So the consensus of a supply at 15L per min sounds reasonable. Maybe a tad higher.

 

[Placo]

I found a way to make this method work partially without the need for a lot of equipment, in this post I explain how to do it, it doesn't guarantee the same purity of gas as a more elaborate method but I'm satisfied, for me it's a good compromise.