Is is possible to breathe from your BCD?

[Slamfire]

4. You could breath tank-air directly via the LPI - depress the deflate and inflate buttons simultaneously and breath from that. If the corrugated hose was u-bent/crimped, you shouldn't get much BCD air in that mix.

And it wouldn't affect your buoyancy.

Have you ever breathed from your BC?

Yes, I have. No emergency. Pure practicing. I'll do 2 to 3 mins breathing out of the inflator. As previously stated, you press both buttons at the same time and you get mostly fresh tank air. Exhale through the nose to avoid putting extra gas in your BC and reduce the likelihood rebreathing higher CO2 content. I've never tried the kinking of the corrugated hose to isolate BC gas. Also, at the surface I can recall having sucked out all the air from my wing a few times. I'm still alive and as far as I know I've never had a fungal lung infection. I do rinse the insides of my BCs with fresh water after every dive and I unscrew the OPV valve and inflator hose to let it "breath" while it's off duty.

[arthurmnev]

Lets re-think this....
His questions is, is it possible to breathe off of a working inflator, and the answer is yes, it is possible.

Now, lets take it a little bit further. Lets say you and your dive buddy really screw up on a cave dive. You've gotten severely lost, and by the time you find your way, you KNOW for a fact that you don't have enough air to make it back to land using the traditional method SCUBA intended. Is it possible to use your wing as a rebreather with the remaining air in your tanks? You inhale from the reg, exhale into the wing. Recycle the gas in the wing 3 times, then discard that gas, and again Inhale through your REG, exhaling through your wing.

Just FYI for those that don't know, we breathe in 21%, we exhale 16% Oxygen. Granted the CO2 levels are growing, but if the crap hit the fan, this is a better alternative than dying.

But how are you going to deal with inflated bc underwater other than tie yourself to something?
And while we are building a scenario what are you doing down there breathing in and out of your bc are you waiting for your buddy are you trying to make your way out?

[flots am]

Pure practicing. I'll do 2 to 3 mins breathing out of the inflator. As previously stated, you press both buttons at the same time and you get mostly fresh tank air.

I hate to bring this up, but you know they make a device that does exactly that, but lets you breathe without adding air to the BC.

flots.

[SkimFisher]

So what you're saying is that you would rather perform a non-recommended procedure that's known dangerous and possibly fatal, instead of a recommended procedure that's been tested by thousands of divers and found to be safe?

flots.

What procedure? You keep referencing a procedure, but which one? Based on the topic, I think we are all assuming that you have no buddy with which to share air. I think we all view breathing off the BC and/or LPI as an absolute last resort. So at 120', what is this procedure you speak of?

[PfcAJ]

120' and no buddy AND you run out of air? Hmm..

[decompression]

I hate to bring this up, but you know they make a device that does exactly that, but lets you breathe without adding air to the BC.

flots.

Not really DIR, is it though?

[flots am]

> Not really DIR, is it though?

This is the "Basic SCUBA" forum, not the "DIR" forum.

flots.

---------- Post added ----------

What procedure? You keep referencing a procedure, but which one? Based on the topic, I think we are all assuming that you have no buddy with which to share air. I think we all view breathing off the BC and/or LPI as an absolute last resort. So at 120', what is this procedure you speak of?

Ummm... The one referenced in the subject line for this thread?

flots.

[XS-NRG]

I asked this same question in OW class. If your regs fail then your LPI may have failed too. If you choose to rebreathe your BC then you're only option at this point is to exhale your breath into your BC and start upwards. You may have air in your BC already. Fresh air from inside it plus air your breathed out would mix and there would still be O2. As you ascend the air would then expand and you would then at this point breath in from BC and exhale into the water. Your BC would run the risk of bursting if you just breathed in an out of it due to expansion as you ascended. Depending on the volume of air you could theoretically breathe 16-17% O2 all the way up because you are exhaling into the water. I would only breathe in about half your lung volume though because that breath would also be expanding in your lungs as you ascend and if you took a full breath you could run a risk of A.G.E. especially if your BC was now providing a runaway ascent. The physics of the operation would be quite tricky especially if you've never done it before and you are panicking.

I wouldn't practice this but if it was my only resort I would consider it. The grunge in the bladder would certainly lead to lung problems if it was dirty inside. You really take a risk either way. Better to practice safe diving techniques and stick with your buddy.

I know this next comment may receive criticism but I'll say it anyway: this is another good reason to consider a pony bottle. Safe diving always trumps all but having a backup certainly isn't the worst idea ever. We do wear seat belts "just in case"

[SkimFisher]

> Not really DIR, is it though?

This is the "Basic SCUBA" forum, not the "DIR" forum.

flots.

Ummm... The one referenced in the subject line for this thread?

flots.

All I see is, "Is it possible to breathe from your BCD?". I don't see anything about a procedure...

[arthurmnev]

I asked this same question in OW class. If your regs fail then your LPI may have failed too. If you choose to rebreathe your BC then you're only option at this point is to exhale your breath into your BC and start upwards. You may have air in your BC already. Fresh air from inside it plus air your breathed out would mix and there would still be O2. As you ascend the air would then expand and you would then at this point breath in from BC and exhale into the water. Your BC would run the risk of bursting if you just breathed in an out of it due to expansion as you ascended. Depending on the volume of air you could theoretically breathe 16-17% O2 all the way up because you are exhaling into the water. I would only breathe in about half your lung volume though because that breath would also be expanding in your lungs as you ascend and if you took a full breath you could run a risk of A.G.E. especially if your BC was now providing a runaway ascent. The physics of the operation would be quite tricky especially if you've never done it before and you are panicking.

I wouldn't practice this but if it was my only resort I would consider it. The grunge in the bladder would certainly lead to lung problems if it was dirty inside. You really take a risk either way. Better to practice safe diving techniques and stick with your buddy.

I know this next comment may receive criticism but I'll say it anyway: this is another good reason to consider a pony bottle. Safe diving always trumps all but having a backup certainly isn't the worst idea ever. We do wear seat belts "just in case"

Well, if you are going into %% of oxygen needed (which is far out of scope of the original question) consider that due to increased depth, PPO will go up, I think the minimal surface PPO is .18, which is 18% oxygen, that will go up with depth. The problem is that CO2 levels (in case of BC breathing will go up as well) which will tell your body that "you are running out of air" which will cause you to breathe more. (this is a reverse of hyperventilating to get rid of CO2 and fool your body into "I dont need to breathe" mode)