Scuba Nitrox Incident for Analysis

[kammel78]

E.g.: Compressed Air Systems: Causes of CO2 Contamination - Compressed Air Testing - Trace Analytics

Interesting, I've always thought it was CO that was more common from exhaust.

 

[John C. Ratliff]

The no bc broke the camels back John C. Ratliff, and even the dumb snorkel that he thankfully didn't use
See there it is a guy starting to drown in still flat water, doesn't dump weights, no need to wonder what happens to divers in a moving ocean
I used to dive no bc before the bc didn't like it, still don't like it can do it to show off but it's too much work, dangerous.
Thank you.

One of the responders on the YouTube site said that I should have immediately dumped his weights. But to me the actual emergency ended when he grabbed the float. Then I was able to talk with him, move him and get him to the dock. That rather obnoxious responder also said that I should have gone straight to shore with him. But shore was actually further away than the dock, and he would have been going backwards through those water weeds, and probably further tangled in them too. So the dock, to me, was the better choice, getting out in deeper water over these water weeds.

SeaRat

 

[John C. Ratliff]

Exactly! Where did you find that picture?
And what is its English name?
Or is this another of those Italian-only diving techniques which never landed in other countries?

English name is a “surface dive.”

SeaRat

 

[tursiops]

Interesting, I've always thought it was CO that was more common from exhaust.

It might be, but the article you quote is about CO2, not CO.

 

[kammel78]

It might be, but the article you quote is about CO2, not CO.

Yes, that's why I was surprised.

 

[JohnN]

Exactly! Where did you find that picture?
And what is its English name?
Or is this another of those Italian-only diving techniques which never landed in other countries?

I googled "capovolta in squadra"

I thought this was an old-school way of descending while snorkeling, I remember being taught a feet first approach and then an underwater pivot, but it wasn't nearly as effective

 

[tursiops]

How does one get CO2 contamination?

E.g.: Compressed Air Systems: Causes of CO2 Contamination - Compressed Air Testing - Trace Analytics

Interesting, I've always thought it was CO that was more common from exhaust.

It might be, but the article you quote is about CO2, not CO.

Yes, that's why I was surprised.

Let's start over again.
You asked how does one get CO2 contamination?
wnissen gave a link, that included exhausts as one possible source of CO2.
You expressed surprise, since you thought CO was more likely from an exhaust
I asked why, since the link was only talking about CO2, which is what you asked about
And then you said that is why you were surprised.

Sorry, I'm confused. The subject was CO2, not CO, or which is more likely from an exhaust.
Just what is it that you are surprised about?

 

[kammel78]

Let's start over again.
You asked how does one get CO2 contamination?
wnissen gave a link, that included exhausts as one possible source of CO2.
You expressed surprise, since you thought CO was more likely from an exhaust
I asked why, since the link was only talking about CO2, which is what you asked about
And then you said that is why you were surprised.

Sorry, I'm confused. The subject was CO2, not CO, or which is more likely from an exhaust.
Just what is it that you are surprised about?

The CGA link within the article said that testing showed CO2 contamination was the most common contaminant in their testing, probably due to compressor location (exhaust).
"Excess carbon dioxide (CO2) is the most common reason found by Trace Analytics’ laboratory for dive retailers to fail the Compressed Gas Association (CGA) Grade E air quality specification."

Maybe it didn't mean CO2 exclusively and that they found CO2, CO and other stuff, but I had just assumed that CO would cause more failed inspections than CO2.

 

[Celt]

The CGA link within the article said that testing showed CO2 contamination was the most common contaminant in their testing, probably due to compressor location (exhaust).
"Excess carbon dioxide (CO2) is the most common reason found by Trace Analytics’ laboratory for dive retailers to fail the Compressed Gas Association (CGA) Grade E air quality specification."

Maybe it didn't mean CO2 exclusively and that they found CO2, CO and other stuff, but I had just assumed that CO would cause more failed inspections than CO2.

I thought the same, why would a compressor intake be in a closed room full of people exhaling CO2, and how much CO2 would there have to be in a tank to affect a diver. Seems bizarre. It can’t have anything to do with this tread as the diver said he was using 36% oxygen

 

[wnissen]

I thought the same, why would a compressor intake be in a closed room full of people exhaling CO2, and how much CO2 would there have to be in a tank to affect a diver. Seems bizarre. It can’t have anything to do with this tread as the diver said he was using 36% oxygen

We're may be getting off topic, but human breath is about 4% CO2, about 100x as much as the atmosphere. The Chemical Composition of Exhaled Air From Human Lungs

So it's not that far fetched that a small room with a compressor and people in it would have excess CO2. And since it's the partial pressure that matters, if you started with 1.5% CO2, descended to 25 meters, you'd have about the same CO2 as exhaled breath. That would eventually leave you feeling very short of breath. I admit that's a crazy high starting concentration unless you have a bunch of people respiring around a compressor in a closet.