Method Exit bag and inert gas megathread

[anonaon]

I want to CTB today. Any recommendations? I will test for leaks now and I will test it on a dummy head with a gas detector. I will not use a oximeter as I think that's enough.

Whats ur method again? Exit bag?

 

[winterparty]

I'm using an eebd hood by 3m scott with a quick coupler and nitrogen. My first test with 25 LPM was fine. The gas detector went down very fast and the last few percentages went down considerably slower. I stopped the gas flow at 0.9% oxygen. The hood is fine. It's all fine. The TV wasn't a good anchor point for the gas bottle though so I'm not sure whether I can do it today. Now I need to have the guts to actually do it.

EDIT: I did a leak test and there was a small leak at the quick coupler. Fixed it. I guess I'm ready to go when I find a anchor point for my gas bottle. The TV wasn't really a good fit.

 

[ztem]

I stopped at 0.9% oxygen

What was your flow rate?

I did a leak test and there was a small leak at the quick coupler. Fixed it

Do the oxygen test again,you should be able to get Vizzy's result(with 20-25LPM).

 

[winterparty]

I was using 25 LPM. I kind of want to show my setup but I'm afraid of it for some reason.

 

[ClownWorld2023]

The forum's search function isn't working for me right now, so I'll ask this question here:

Anyone here who bought a EEBD set and actually tested breathing oxygen with the hood in a lying down position?
Does it breathe comfortably (CO2 purged properly) ?


I found a local source that sells an EEBD hood and hose, without the oxygen cylinder.
I could purchase it for cheap if I don't need the oxygen cylinder for any other purposes (like testing).

If someone else has already tested this, please let me know.



EDIT: Nvm. I just found out that most EEBDs use a flow rate around 35-40 LPM, which is way higher than used for the inert gas method.
So I can't use the EEBD set's oxygen supply for testing purposes.
I'll most likely order the standalone EEBD hood.

 

[FailerQt.]

The flowmeter that GasMonkey suggested has a hose barb,so you don't need to worry about buying the right size hose barb but you should worry about buying a hose with the right ID size for the hose barb of that flowmeter

I noticed you're still active here, so decided to see if I could get a bit assistance. I ended up getting the flowmeter GasMonkey recommended and as you said it has the barb. The site is however in German and I am not sure what kind of hose I need to exactly get since I can't speak German. Is there anything you'd recommend? Feel free to pm me if sharing here is not allowed. And thank you in advance if you answer!

 

[ztem]

If the size of your barb is 1/4"(6mm), then you need Oxygen tubing or PVC tubing(1/4"ID).In theory,1/4" barb is for hose/tube with 1/4" ID but one of the members said it's hard to connect 1/4" ID to 1/4" barb.You can buy PVC tubing with 3/8" ID and if the connection is not tight enough,use a hose clamp.

 

[FailerQt.]

If the size of your barb is 1/4"(6mm), then you need Oxygen tubing or PVC tubing(1/4"ID).In theory,1/4" barb is for hose/tube with 1/4" ID but one of the members said it's hard to connect 1/4" ID to 1/4" barb.You can buy PVC tubing with 3/8" ID and if the connection is not tight enough,use a hose clamp.

Thank you!

 

[unebarque]

Can anyone PM me sites to order a nitrogen tank from (UK) without business verification? Thanks!

 

[ClownWorld2023]

Can anyone PM me sites to order a nitrogen tank from (UK) without business verification? Thanks!

There's a source mentioned in the PPH.

You can check whether they can send to the UK.

I don't know how it works with the UK customs (whether they will allow it to be imported, and tariffs imposed, if any).

Keep in mind that the shipping costs can be really high, and that refill is pretty much impossible, though you may be able to find local welder shops that are willing to refill.

 

[DeadHead]

Can anyone PM me sites to order a nitrogen tank from (UK) without business verification? Thanks!

I tried to msg you as I just ordered in UK, however because you are new I can't pm you
I would appreciate it if one of the experts here could answer my (probably retarded) question.

Here is a pic of my nitrogen tank below and I've also posted a link to the regulator I am thinking of buying. To join the regulator to the tank, you literally have to rotate the whole regulator round and round until it's screwed in - is this correct? I can't imagine how else you would do it. So if the regulator is heavy, this could be difficult for people with certain medical conditions.
This regulator: https://norsemensafety.co.uk/produc...MI9YXRl_OIgQMVSNftCh0RNwg3EAQYASABEgLycPD_BwE

 

[ztem]

To join the regulator to the tank,

Connect the reg to the cylinder and tighten it with a wrench,open the cylinder valve slowly and fully and adjust the flow rate with this,that's it.

 

[outrider567]

Espe

Connect the reg to the cylinder and tighten it with a wrench,open the cylinder valve slowly and fully and adjust the flow rate with this,that's it.

Yes, and tightening it with a wrench is of paramount importance

 

[NoFutureAnymore]

I recently received my SCUBA materials and I decided to do a few tests. Firstly I tested how much the pressure drops after opening and closing the cylinder. The pressure barely dropped after 10 minutes waiting, so this was all good. After that I decided to proceed with the blackout test. While I was doing this I had an oximeter around my finger. The first blackout test failed due to this oximeter which started to beep and scared me. I probably also purged some air since the pressure suddenly dropped to 190 bar. I proceeded with my second attempt after turning off all the alarms of the oximeter.
And it worked, I passed out for a very short time. First everything got black and then I felt my hand, which was holding the mask, falling on my leg.
So far so good I guess. The total time from pushing the mask against my facing and waking up was maybe 50 seconds if I look at the image below.

But the thing which worries me is that the pressure dropped to +-182 bar during my second attempt. So this means that I consumed 8*5L = 40 liters in this short time. So this means that I would consume the remaining part in 18 minutes. What am I missing? Is it only the first minute that you consume so much and will the consumption go down after passing out?

 

[dm1444]

But the thing which worries me is that the pressure dropped to +-182 bar during my second attempt. So this means that I consumed 8*5L = 40 liters in this short time. So this means that I would consume the remaining part in 18 minutes. What am I missing? Is it only the first minute that you consume so much and will the consumption go down after passing out?

Direct-acting regulators have a dropping characteristic, i.e. the operating pressure also decreases as gas is consumed

 

[NoFutureAnymore]

Direct-acting regulators have a dropping characteristic, i.e. the operating pressure also decreases as gas is consumed

My mask already felt off (I didn't make it tight, otherwise I probably would be dead by now) before reading the pressure gauge (so no consumption at that point). So this dropping characteristic can't be the reason. I think I guess I was stressed and was breathing fast. So I think my question is, what happens to this fast breathing after passing out? Or should I be really focused on my breathing before and after putting my mask on?

 

[dm1444]

NoFutureAnymore Is the valve on the cylinder fully open?

 

[NoFutureAnymore]

NoFutureAnymore Is the valve on the cylinder fully open?

Yes, it was fully open.

 

[dm1444]

Yes, it was fully open.

Have you checked all the connections for leaks?

 

[NoFutureAnymore]

Have you checked all the connections for leaks?

Yes, I did a pressure test by closing the cylinder valve. The pressure remained almost the same for 10 minutes. It really went down with +/-8 bar by doing my blackout test.

 

[dm1444]

NoFutureAnymore

Did you buy the tank new (with gas) or refill it?

 

[NoFutureAnymore]

NoFutureAnymore

Did you buy the tank new (with gas) or refill it?

It's an exchange cylinder of 200 bar, you hand in the old one and get another filled one in return. It's already lying here for weeks and it was still 200 bar when I started today. So that one isn't leaking neither.

 

[ClownWorld2023]

I tried to msg you as I just ordered in UK, however because you are new I can't pm you
I would appreciate it if one of the experts here could answer my (probably retarded) question.

Here is a pic of my nitrogen tank below and I've also posted a link to the regulator I am thinking of buying. To join the regulator to the tank, you literally have to rotate the whole regulator round and round until it's screwed in - is this correct? I can't imagine how else you would do it. So if the regulator is heavy, this could be difficult for people with certain medical conditions.
This regulator: https://norsemensafety.co.uk/produc...MI9YXRl_OIgQMVSNftCh0RNwg3EAQYASABEgLycPD_BwE
View attachment 120835

You only have to rotate the connector nut at the regulator's inlet, not the entire regulator.

The regulator should weigh 2kg at most.
You can sit on a chair with armrests and have your arm lean on it if it still proves troublesome.

You tighten the inlet nut by hand until you can't put force anymore.
After that you use the wrench to tighten it a bit more.
If you feel noticeable resistance, then you've probably tightened it enough.
Do not overtighten it, as it may damage the thread.

Leak checking can be done after this. If there is a leak, you can tighten it a little bit more, until no leaks are found.

EDIT: Sorry for the late reply. Didn't see the above posts.

 

[dm1444]

It's an exchange cylinder of 200 bar, you hand in the old one and get another filled one in return. It's already lying here for weeks and it was still 200 bar when I started today. So that one isn't leaking neither.

I refilled my 5 liter tank too and the pressure dropped quickly too. I suspect that the gas is much less than that. I'm thinking of changing to a 10 liter tank.

 

[ClownWorld2023]

I found my gas cylinder pressure also dropping quicker than I expected.

Either I didn't keep track of time properly, or something else is going on.
(No leaks, I checked the cylinder valve itself, the regulator, and finally the outlet hose.)


Also, I don't really remember, but I recall my gas cylinder had a higher pressure than 200 bar at the beginning, like somewhere near 245 bar.
At the beginning I made the foolish mistake of not tightening the regulator with a wrench (because I didn't have one), and thinking it would have been sealed properly.
So opening the valve, quite a lot of gas escaped at the beginning.
After that I tightened the regulator with some other tool that wasn't really suitable for it.
I only bought a wrench later.
(Anyway, don't make these stupid mistakes like I did. I just wasn't familiar with this kind of technical stuff at all.)


I think the real starting pressure must have been something near the 250-270 bar range.

It would be nice to get some more information about this from someone who understands this better.

 

[winterparty]

How does it feel to pass out from nitrogen? I'm about to CTB

 

[NoFutureAnymore]

I refilled my 5 liter tank too and the pressure dropped quickly too. I suspect that the gas is much less than that. I'm thinking of changing to a 10 liter tank.

What is your method again?
If I remember wel, I was breathing really fast. Maybe close to hyperventilating and at some point I thought "I should breath slower". So I forced myself to breath slower. After that I can't remember anything. According to ChatGPT, your breathing slows down after you pass out and is regulated by CO2 levels in your blood. Which should be low, so breathing goes down as far as I understand. Would be nice if somebody can confirm this, since ChatGPT isn't always correct.
I still have some prescription drugs to relax, so maybe I should take it if I want to CTB. Put my mask on with the bypass valve open and wait until my breathing is normal before closing it.
I also read that SlovakGuy had a bottle of 6L and had 87bar left after he died. Does anybody know if he started with a full cylinder? Or did he also loose some gas before ctbing?

After that I tightened the regulator with some other tool that wasn't really suitable for it.
I only bought a wrench later.
(Anyway, don't make these stupid mistakes like I did. I just wasn't familiar with this kind of technical stuff at all.)

Yes I wasted a few bars in the beginning by using the tools which where including with the SCUBA gear which where not strong enough. It kept leaking a bit. I took some real tools which I have lying around and after that the pressure didn't change anymore.

How does it feel to pass out from nitrogen? I'm about to CTB

It felt comparable to falling asleep. First few breaths not much happend and then my hands started tingling a bit and the vision got a bit blurry, but it went al so fast that I even didn't realize this. The realization came after I woke up again. This waking up also went quite fast as soon as the oxygen is restored. I took a few deep breaths to get rid of the strange feelings.

 

[ztem]

I refilled my 5 liter tank too and the pressure dropped quickly too. I suspect that the gas is much less than that. I'm thinking of changing to a 10 liter tank.

Slovak guy had a 6L/200bar cylinder and only consumed 678 liters of it with his NP SCUBA but if 10L/200bar will increase your confidence,go for it.

Firstly I tested how much the pressure drops after opening and closing the cylinder. The pressure barely dropped after 10 minutes waiting, so this was all good

Although the HP leak test is recommended in the SCBA/SCUBA manual, it is not enough because you can have leak while the HP leak test is satisfactory.

I consumed 8*5L = 40 liters in this short time. So this means that I would consume the remaining part in 18 minutes.

Those calculations are for SCBA cylinders for firefighters.
For example:
6.8L × 300bar ÷ 40LPM - 10(for safety margin) = 41 minutes

or

They recommend that firefighters immediately exit the hazardous area when they hear the low pressure alarm/whistle of their SCBA.This whistle will activate at ~50 bar pressure.
6.8L × 300bar = 2040L
6.8L × 50 bar = 340L
2040L - 340L= 1700L
1700L ÷ 40LPM = 42 minutes

With PP LDV:
Wunderkind lost 20bar with 5L/150bar cylinder
Das Nichts lost 40bar with 5L/220bar cylinder

It's better to buy a separate 5L/200bar(or instead of two 5/200, just one 10/200) for blackout test with SCBA because after you pass out, that PP LDV will go crazy.

 

[NoFutureAnymore]

Slovak guy had a 6L/200bar cylinder and only consumed 678 liters of it with his NP SCUBA but if 10L/200bar will increase your confidence,go for it.

Do you know if he started with a full cylinder?

Although the HP leak test is recommended in the SCBA/SCUBA manual, it is not enough because you can have leak while the HP leak test is satisfactory.

Uhm so it might still leak at the cylinder. Is this caused by a check valve? However I still don't think this was the case (I will still do this extra check next time with the spray). The pressure didn't go down when everything was connected with the mask off. So if there was a leak then the pressure should also have gone down before and after my test (the valve was open). The most likely explanation is my breathing which was really fast and deep (I felt extremely nervous, maybe SI because I didn't want to die yet). It might have been as fast as when you normally do "heavy physical exertion". My 50LPM consumption during this 50 seconds falls in the range of your screenshot.

Those calculations are for SCBA cylinders for firefighters.
For example:
6.8L × 300bar ÷ 40LPM - 10(for safety margin) = 41 minutes

My cylinder is now at 182 bar. So that's with this extreme consumption 5 * 182 / 50 = 18 minutes.
When I decide to CTB I will try to relax more and take some medication to help relaxing, so I hope I can manage to get my breathing down to 12LPM.
And I hope that it will anyway go down to 12LPM minute after passing out.
So that's worst case 182-8 bar = 174bar at the moment of passing out and then there are 5 * 174 / 12 -10 = 62 minutes left while being unconsciousness. Or am I seeing something wrong?

 

[ztem]

-10

That -10 is for firefighters,they consider that 10 minutes of remaining air in the cylinder to get out of dangerous environments.

If your breathing rate is really 50LPM when you are stressed and anxious, then yes, you will breathe about 50LPM in the first minutes,cessation of breathing happens in less than 5 minutes.