Diving 32% Nitrox with "Air" Algorithms

[scubadada]

Sad that the simplest threads get the most responses, perhaps because everyone feels qualified to reply

 

[arew+4]

Inflammation of airways and lungs due to oxygen.
Increased metabolism and consequent reduction of sugar.
Hypoxic drive, causing shallow breathing, CO2 retention and consequent narcosys.
All the side effects reported with oxygen therapy: What are the Possible Side Effects Of Oxygen Therapy? | VitalAire Canada

Another nicely irrelevant post, oxygen therapy for folks with compromised respiratory systems.

 

[arew+4]

That was also a response to post #224, which also was a response to you.

Read it!

Abstract
Reactive oxygen and nitrogen species (RONS) are produced by several endogenous and exogenous processes, and their negative effects are neutralized by antioxidant defenses. Oxidative stress occurs from the imbalance between RONS production and these antioxidant defenses. Aging is a process characterized by the progressive loss of tissue and organ function. The oxidative stress theory of aging is based on the hypothesis that age-associated functional losses are due to the accumulation of RONS-induced damages. At the same time, oxidative stress is involved in several age-related conditions (ie, cardiovascular diseases [CVDs], chronic obstructive pulmonary disease, chronic kidney disease,

Reactive oxygen species
Article Talk
Language
Download PDF
Watch
Edit
In chemistry, reactive oxygen species (ROS) are highly reactive chemicals formed from diatomic oxygen (O2). Examples of ROS include peroxides, superoxide, hydroxyl radical, singlet oxygen,[1] and alpha-oxygen.


Lewis structure of some of the reactive oxygen species.
A: hydroxyl radical (HO•);
B: hydroxide ion (HO−);
C: triplet oxygen (O22•);
D: superoxide anion (O2•-);
E: peroxide ion (O
2−
2
);
F: hydrogen peroxide (H2O2);
G: nitric oxide (NO•)

The 1000 hrs of elevated O2 you get in a life time of diving EAN isn't going to amount to sh!t compared to all the toxic chemicals you will inhale, imbibe, and eat.

 

[Bigbella]

In the interest of adding "conservatism" to our diving, my wife and I when diving the tropics (mostly shore diving on Bonaire ) dive 32% Nitrox. But to increase safety, we still keep our computers set to Air. We fully understand and adhere to the 111ft MOD for 32% and we even augment that by agreeing to stay inside of 100ft max depth as a rule. We just keep our computers set to AIR to add in some more "conservatism" . We then plan and dive the AIR algorithms ....... and NEVER go below the MOD for 32% Nitrox.

Anyone else do this........or does anyone have a reason why not to do this?

I guess that I don't quite understand that rationale.

Most every dive computer that I had ever owned, since the early 1990s offered some varying levels of "personal adjustment settings" for diving on air, from Suunto, through Oceanic and Shearwater -- and some even suggested hiking the altitude adjustment for greater conservatism . . .

 

[NW Dive Dawg]

I guess that I don't quite understand that rationale.

Most every dive computer that I had ever owned, since the early 1990s offered some varying levels of "personal adjustment settings" for diving on air, from Suunto, through Oceanic and Shearwater -- and some even suggested hiking the altitude adjustment for greater conservatism . . .

I get your point...... but isn't making a false altitude adjustment still "lying" to your computer to create a more conservative profile?

 

[Cheizz]

It's a little less than 1.6, and 1.6 is considered the contingency depth. If you take a nitrox class, which apparently you have not, you will be taught that although 1.4 is the standard, it is acceptable to go to 1.6 when needed. (That is with almost all agencies.)

I have done a Nitrox class actually. And I called it a risk (otherwise 1.6 would be the standard and not 1.4). I didn't call 1.6 certain death.

You assume a lot and don’t read very carefully.

 

[clownfishsydney]

I love all the divers commenting on this topic who have less than 100 or 200 dives experience. Unless you are a medical professional, then perhaps you should realise you do not have the experience to understand this whole subject.

Unless you are diving very high oxygen percentages and/or very very long and deep dives, then oxygen exposure will never be a problem.

The only person I know who has ever come close to this is a person who was doing very deep dives over consecutive days and using 100% oxygen for decompression. The impact on him was his vision was affected, but he actually did not need glasses to read for many months.

 

[boulderjohn]

I have done a Nitrox class actually. And I called it a risk (otherwise 1.6 would be the standard and not 1.4). I didn't call 1.6 certain death.

You assume a lot and don’t read very carefully.

I reacted to the entire sequence of steps in which you participated.

Step 1: Arew+4 wrote: "Even if you went to rec limit of 130' on EAN 32, your max ppo2 would be just under 1.6 WHILE THIS IS AN UNACCEPTABLE LEVEL OF RISK, it is not guaranteed to cause O2 toxicity or cns symptoms." His use of all caps in saying it was an unacceptable risk emphasized that point of view.

Step 2: I asked why it was such an unacceptable risk if it is listed as acceptable on dive tables.

Step 3: You responded in the next post by stating that the PPO2 made it a risk.

While you did not say it was "certain death," and I did not say you did, you did support an all-caps statement that the risk was unacceptable.

In the strictest of terms, all diving is "a risk."

 

[Belzelbub]

I get your point...... but isn't making a false altitude adjustment still "lying" to your computer to create a more conservative profile?

Yes. I would say it is.

If dealing with an older (antique?) dive computer, you may be forced to lie to your computer in order to add a safety buffer.

But, I'd be hard pressed to find a computer today that doesn't offer some method of adding conservatism. So, if you have a computer that can support additional conservatism, exercise that first. The manufacturer went through the effort to add in that adjustability, so why not take advantage of it.

Even if your computer doesn't have conservatism adjustments, that doesn't mean that you can't set your own personal safety buffers. Just because an NDL line exists, that doesn't mean you need to be just under NDL on every single dive. Keeping a personal goal of 5 minutes, 10 minutes, etc. is perfectly acceptable. My computers offer custom GFs, so I can pretty much set whatever safety buffer I want. Instead, I have them set relatively liberal, but still use personal safety buffers to make sure I stay as safe as possible.

 

[BoltSnap]

Just because an NDL line exists, that doesn't mean you need to be just under NDL on every single dive. Keeping a personal goal of 5 minutes, 10 minutes, etc. is perfectly acceptable.

Exactly, this is the most important point.