Breathing the gas from your BCD

[Bento.Box]

A bold claim. I have seen an OOA situation where a first stage got blocked when a diver went vertical head down and crap inside the tank blocked the first stage.

given that tanks are regularly inspected, this should be an exceptional rare occurance.

Still, you have a 2nd first stage that may or may not be clogged (they are usually designed to fail open). You have the air from your buddy or your redundant air if you go solo.

And for additional safety, you could carry a spare air.

 

[Coelacanthic]

A more efficient way to rinse your BC after a dive is to cannabalise an old power inflator hose with a quick garden hose tap connector. Clip to the power inflator. You can flush the bladder, hose and inflator properly. Any unwanted contents will be flushed out via the dump valve. Sanitiser can be added to the inflator beforehand and flushed in by the water.

 

[boulderjohn]

I stand (well, sit) corrected, so far as current standards go. Is that surface inflation or buoyancy management underwater?

Both. For example, students have to demonstrate the ability to hover while controlling their BCD inflation orally. They also have to demonstrate it on the surface for following a CESA because their cylinder is supposedly empty.

 

[TrimixToo]

<snip>

The link to the article is posted on this thread by another member that's how I found it.

That article does not cite a credible study. It merely cites the result of a single test with unspecified parameters and limits: "Tests conducted by the late Al Pierce of the YMCA concluded that you can exhale back into your BCD and keep rebreathing the same air as many as 13 times without becoming overly hungry for fresh air."

In particular, it does not address depth, PPO2 or PPCO2. Further, it does not compare the ratio between tidal volume and BC volume. If there were a link to Al Pierce's documentation for the test, we might get somewhere, but there's not. I'd be very hesitant to accept 13 as the value of *n* based on the information available in that article. Most of the breathing reflex is triggered by the blood level of CO2.

This is not a simple question. As you rebreathe some of the same gas, the PPO2 declines and the PPCO2 increases. It could be a race between hypoxia and hypercapnia depending on initial depth and ascent rate. I'm not going to attempt the math. That's why I was interested in an actual study.

 

[boulderjohn]

Further, it does not compare the ratio between tidal volume and BC volume.

As has been mentioned several times in this thread already, at the end of the dive, a BC should have very little air in it.

 

[Belzelbub]

A more efficient way to rinse your BC after a dive is to cannabalise an old power inflator hose with a quick garden hose tap connector. Clip to the power inflator. You can flush the bladder, hose and inflator properly. Any unwanted contents will be flushed out via the dump valve. Sanitiser can be added to the inflator beforehand and flushed in by the water.

True.

There are also a couple of other options that can be purchased and work without having to swap the corrugated.

XS Scuba (and others possibly) have a BC washout hose. This attaches to the quick connect on the inflator and connects to a garden hose. You hold down the inflate button, turn on the hose and water fills the BC.

Zeagle inflators, Octo-Z and Atomic SS1 (not sure about the Atomic Inflator) offer a more hands-off solution. The inflator or Octo-Z/SS1 simply unscrews from the end of the corrugated hose. A garden hose can then be attached and turned on. You can let it run and rinse while it does the work.

While I have no intention of breathing from my BC, I'm fairly confident that the inside of my BC is clean enough should I find myself in a situation where it might be necessary.

 

[TrimixToo]

Both. For example, students have to demonstrate the ability to hover while controlling their BCD inflation orally. They also have to demonstrate it on the surface for following a CESA because their cylinder is supposedly empty.

Good. I think it's important to be able to do both.

As has been mentioned several times in this thread already, at the end of the dive, a BC should have very little air in it.

Fair enough.

 

[Blackcrusader]

As has been mentioned several times in this thread already, at the end of the dive, a BC should have very little air in it.

Yes but lets say you are at deeper then 25m, have some air in your BCD or not.. the point is you exhale back into the BCD and do not exhale. You make it to the surface alive is all that is required. It's use if for an exceptional time.
I am often the last in a group of divers.... rarely do other divers look behind. I find insta buddies will not stay with a photographer they just follow the guide instead. It seems the buddy rule just goes away like a fart in the wind with some divers.

So in effect I just became a solo diver. I rely on myself first.

 

[boulderjohn]

Yes but lets say you are at deeper then 25m, have some air in your BCD or not.. the point is you exhale back into the BCD and do not exhale. You make it to the surface alive is all that is required. It's use if for an exceptional time.
I am often the last in a group of divers.... rarely do other divers look behind. I find insta buddies will not stay with a photographer they just follow the guide instead. It seems the buddy rule just goes away like a fart in the wind with some divers.

So in effect I just became a solo diver. I rely on myself first.

Why not just head to the surface with a CESA or buoyant ascent?