100m air dive & workup, PG

[Kevrumbo]

Re-posting & quoting Joel Silverstein's (an old bold & bald NE Wreckdiver) anecdote post on extreme PO2 Exposure:

. , ,We removed the Exceptional Exposure Oxygen tables from the NOAA diving manual 4th editon because there was fear that if the general public saw them printed that they might take it as an endorsement to use them.

The NOAA exceptional exposure limits are set for extreme emergencies only and are not for routine use. IE: should be used for life saving only.

These are for a working dive meaning with lite exertion. Remember that there are a variety of factors that come into oxygen toxicity, and crossing the 1.6 atm 45min line does not guarantee convulsion, it also does not guarantee it won't.

NOAA OXYGEN
EXCEPTIONAL EXPOSURE LIMITS
PO2 Minutes

2.8 5
2.4 10
2.0 30
1.9 45
1.8 60
1.7 75
1.6 120
1.5 150
1.4 160
1.3 240


As you can see the exceptional times allow you a fairly large margin to use this method for an "escape." The table is NOT linear. Note that exceptional exposures are DANGEROUS and can only be done once in a day. . .

Decompression Gases

My personal physiological deep air depth limit was a solo dive descent approaching 60m in the Nagano Maru's cargo hold, Chuuk Lagoon 2007: Started seeing the "starfield simulation Windows screen saver" all around me, which at the time I thought was due to the severe nitrogen narcosis at 7 ATA ambient pressure (immediately ascended out of the cargo hold and stayed on the deck around 45 to 51m for the duration of the dive). In retrospect however after reading some of the above Rubicon articles, the effect could also have been the beginning symptoms of an Ox-tox event just as well (PO2 at 1.5 ATA). . ,

 

[Tortuga68]

Can you honestly imagine a race car driver forum where people discuss how many drinks you should have before a race and what your 'work up' training is?

No, because that's a poor analogy with only superficial resemblance to deep air diving - alcohol is not an inherent part of car racing; narcosis and exposure to increased partial pressures of gasses are an inherent part of scuba diving no matter what mix you're breathing or how deep you're diving

Can you imagine glider pilots discussing how long you should fly in a mountain wave without oxygen and how you work yourself up to the edge of mental incapacitation?

Can you imagine mountain climbers discussing ascending over 8000m without oxygen, and how to acclimatise yourself to altitude? (Hundreds of people have died on Mt. Everest)

Can you imagine long-distance runners discussing running 26 miles in extreme temperatures, and how to hydrate themselves? (Amateur marathon runners die from hyponatremia)

These are also voluntary activities that non-professional people choose to do for enjoyment even though there are viable alternatives that may be lower risk

 

[vladimir]

Tortuga, I was just renewing my DAN (Asia Pacific) and saw this in the coverage limitations:

In the event of a dive injury insurance claim for a depth beyond 50m, a Member will be required to demonstrate that he/she held an appropriate certification for the dive and was using appropriate breathing gas mixes and equipment during the covered dive or Repetitive Dive Series.

You probably use the same insurer. Have you checked whether they view air as an "appropriate breathing gas mix"?

 

[Tortuga68]

Yes, I have DAN insurance, and had also noted that clause myself some years ago when I first joined - thanks for the heads up though. I also have private expat medical insurance which covers diving too, although the details of the policy are a little vague

No, I have not checked the DAN specifics - but I highly doubt DAN would cover 100m on air. I couldn't see them covering air any deeper than 55m (based on Extended Range certification) really, since I'm not aware of any agency that certifies you for air use deeper than that (PSAI Narcosis Management is not a depth certification course)

 

[vladimir]

I also have private expat medical insurance which covers diving too, although the details of the policy are a little vague

Blue Worldwide Expat, maybe? That's what I have--I am not aware of any exclusion for diving, though, as you say, the details of the policy are a little vague.

 

[Tortuga68]

No mine's from QBE/AXA. Since the DAN isurance policy is suplemental, my first claim would be on my expat medical anyway - I've asked them and they do cover diving, hyperbaric treatment, evacuations & etc - and whatever residual remained I'd have to try and claim from DAN

Not that I plan to be making any claims either way

 

[CuNanoTube]

I am not really sure if there is known LD-50 for O2 at various depth.

Mark Andrew did his 150m air dive also in PG.

An LD-50 would be very difficult to find for O2 at depth, we would have to develop scuba kits to sent the mice / rabbits down.

I would go with our experience on this one.

 

[VooDooGasMan]

I got a pm on deep air diving, ok I have not mentioned 300' in a long while, and found I posted here.

Did not read after I posted, crogue has a good point of view, you have to approach it cautiously, and with full awareness on decent.

I am by no means, want to teach how to dive deep air, its a dive you want to adapt yourself to. Kev has shown ya the po2, you need to find your po2, only you can achieve this.

Ok Now I was going to do a thread on my 310' deep air dive on hp 100's (I do pump it up for more cf, yea I cheat), and well decided not, maybe I did post it but can't find. This is a thing for a way to be prepared for a tropical warm water dive, with only rec dive available.

Now I shall dive single lp steel 80's, 95's, to deep depths on air, these will all be pumped to lets say cave fills. Now I will spend more time on bottom, and a little longer on deco.

Always teach yourself to dive in a comfort zone of your own depth, Never actually have to reach that goal, it will come in time.

Any ways I have to dive everyday to get all the lingcod use to me hanging with them so I can start slaying them in 6 weeks from now. I Have no Idea if I will ever make to the surface once I descend, yet always have.















Happy Diving

 

[Tortuga68]

There are a lot of people on this board - and IRL - who do or have done deep air

Most won't post about it and communicate via PM to avoid the incoming ****storm from the usual suspects, who appear in every deep air thread and say the same things

/shrug Welcome to Scubaboard!

 

[lowviz]

Tortuga68,

-Been waiting this thread out for quite a while now, looks like deep air narcosis has finally been covered.

My question concerns Type IV DCS (dysbaric osteonecrosis). Since I'm venturing deeper into the tech world, this is something that I often wonder about. My concern stems from the uncomfortably high incidence in commercial, military, and shellfish divers.

Care to share your thoughts / experience on this?