Nitrox mixes above 40%?

[616fun]

I have often thought it make make sense for liveaboards to make 75% available on the hang bar for more efficient safety stops, but I have never seen it and I am guessing it will never happen for lots of different reasons.

My guess is most shops aren't going to invest the money in a booster to offer this. Getting a tank with 75% at a decent pressure is tougher than it appears.

 

[wedivebc]

FWIW, I am aware of at least one incident where a diver toxed at a PPO2 of 1.4. Different people have differing sensitivities to high PPO2's.

If it is the same incident I am thinking of it also likely involved certain over the counter medication.

 

[currier]

Scuba Dive Medical Articles ? Decompression, Heart Safety ? DAN | Divers Alert Network

An interesting read.

 

[billgraham]

Just finished "The Last Dive." They mention several times about hanging reg with pure O2 over the side to aid in decompression. I am not a deep tech diver, but I imagine that is still done on some boats. Although, the techology has probably evolved extensively since the early '90s. I imagine a lot of the equivelent divers today would be using CCR rather than carrying elaborate selections of tanks with different mixes on the extreme dives described in the book. I you want to read about the penalties of ox-tox it describes several instances and gives some very dramatic descriptions of what happens when you screw the pooch in really deep water.

The problem with hanging deco/safety gas on an equipment line or whatever is what happens when the boat breaks loose? The CCR is nice but you have to carry bailout bottom and deco gas anyway, so you still have roughly the same amount of "stuff".

 

[Colliam7]

FWIW, I am aware of at least one incident where a diver toxed at a PPO2 of 1.4. Different people have differing sensitivities to high PPO2's.

If it is the same incident I am thinking of it also likely involved certain over the counter medication.

In the recent issue of Alert Diver, Petar Denoble also refers to a case of a diver reporting symptoms of oxygen toxicity at a pPO2 of 1.3. The diver happened to be taking a prescription medication, for ED, which probably contributed to the event. But, it adds emphasis to the potential for symptoms at lower pPO2 values. What is more interesting to me, however, is what Petar wrote at the conclusion of the article: 'The best protection is to keep inspired oxygen pressure at or below 1.2 while physically active, . . . '. I don't know if the statement was intended simply as a general comment about a possible conservative suggestion of an approach to minimizing risk, or as a more specific recommendation. I mentioned to a DAN colleague that the potential legal implications of such a statement are intriguing, where many agencies refer to a MOD associated with a pPO2 of 1.4 in their recreational enriched air courses.

 

[Doppler]

Guys... worth noting that the 24-hour limits set by NOAA are the ones I suspect in all these "low partial pressure" incidents. It's not just the single dive numbers but the daily limits too that we need to watch

 

[darushin]

The problem with hanging deco/safety gas on an equipment line or whatever is what happens when the boat breaks loose? The CCR is nice but you have to carry bailout bottom and deco gas anyway, so you still have roughly the same amount of "stuff".

Depends on your preference and what standards you are following. If you are in a group of three and the team is comfortable with it, you only need to carry 1/2 the amount of the maximum deco gas you need to complete deco. This per TDI standards

Daru

 

[flots am]

Does it mean you have to be tec certified before you can venture into rebreather?

Rebreather diving is a completely different animal. A rebreather can quietly kill you and you'll never know anything happened.

Rebreather usage procedures, maintenance and prep is more like what you would expect from an anesthesiologist, not a SCUBA diver.

flots.

 

[wedivebc]

Rebreather diving is a completely different animal. A rebreather can quietly kill you and you'll never know anything happened.

Rebreather usage procedures, maintenance and prep is more like what you would expect from an anesthesiologist, not a SCUBA diver.

flots.

What a total load of crap!

 

[billgraham]

Depends on your preference and what standards you are following. If you are in a group of three and the team is comfortable with it, you only need to carry 1/2 the amount of the maximum deco gas you need to complete deco. This per TDI standards

Daru

I don't do the team bailout thing. The boat broke loose, all three of you are going to deco on one lift bag string?

Rebreather diving is a completely different animal. A rebreather can quietly kill you and you'll never know anything happened.

Rebreather usage procedures, maintenance and prep is more like what you would expect from an anesthesiologist, not a SCUBA diver.

flots.

The first part of that statement is true, but as far as the set up, maintenance and prep go, it's not all that much different than ordinary scuba gear. I sure spend a lot less time goofing around making nitrox and trimix.