Requiring shallow helium mixes?

[Kay Dee]

You're right. I forgot about the 1.6 crowd and just ballparked. Cameron

Hi Cameron,

Would you be kind enough to elaborate / clarify on just what you mean by the '1.6 crowd' please ?

Just wondering what that brief statement actually means in this instance is all.

TIA

 

[northernone]

Hi Cameron,

Would you be kind enough to elaborate / clarify on just what you mean by the '1.6 crowd' please ?

Just wondering what that brief statement actually means in this instance is all.

TIA

Those who might be comfortable with 1.6 ppo2 rather than 1.8 or 1.4. It was (is) a fairly common maximum so there might be a lot of divers. Would you prefer the term pod, or school, perhaps gaggle? Joking aside maybe just (unable to add an option for ppo2 1.6) and leave it at that

 

[Basking Ridge Diver]

Would you be kind enough to elaborate / clarify on just what you mean by the '1.6 crowd' please ?

He is referencing PO2 - Partial Pressure of 1.6 rather than 1.4 thought/proven to be generally safer.

Disregard I see Cameron answered.

 

[100days-a-year]

P02 is whole nother critter,I am unconvinced 02 is as big a friend as claimed.I try to limit my exposure to <1.0 as the effects of long term heavy exposure are riskier to me than N or HE.

 

[RyanT]

P02 is whole nother critter,I am unconvinced 02 is as big a friend as claimed.I try to limit my exposure to <1.0 as the effects of long term heavy exposure are riskier to me than N or HE.

Not sure I understand what you mean by long term exposure. Oxygen exposure on the order of minutes to hours can have important negative health consequences ranging from seizures, to pulmonary toxicity (e.g. inflammation of the respiratory membranes), to systemic inflammatory responses from oxidative stress. Seizing underwater obviously has some serious consequences. That aside, however, the negative effects of prolonged/high PO2 exposure are fairly short lived. In addition, there is some evidence that pure O2 exposure can have some beneficial short-term effects of reducing inflammatory responses to micro bubble formation (hence one reason why DCS patients are treated on O2).

 

[sunnyboy]

One thing missing from the poll is type of diving, i.e. OC vs. rebreather.

With a rebreather, it's quite inexpensive to put helium in the diluent. Consequently I have helium for dives 100ft and deeper.

As for suit gas, due to the small size of diluent tanks, I always have a 6cf suit gas cylinder on my rig. So helium in my diluent does not go into my suit.

 

[stuartv]

One thing missing from the poll is type of diving, i.e. OC vs. rebreather

The poll is about what you "require". What is the depth where you would not plan to go deeper, period, unless you had helium? Are you saying that number is different for you depending on whether you are going OC or CCR?

 

[sunnyboy]

I don't go deep on OC anymore, so the number does not change for me. If it's deep or long, then I'm on my Prism Topaz. If it's deeper than 100ft, then my diluent has helium in it.

I wondered about that "requires" thing in the thread title. I always wonder who these scuba cops are who "require" stuff. I don't require anything except getting to dive frequently.

 

[stuartv]

I don't go deep on OC anymore, so the number does not change for me. If it's deep or long, then I'm on my Prism Topaz. If it's deeper than 100ft, then my diluent has helium in it.

I wondered about that "requires" thing in the thread title. I always wonder who these scuba cops are who "require" stuff. I don't require anything except getting to dive frequently.

I took it as "what do I require for myself?" Fortunately, when I arrest myself, it does not go down on my permanent record.

 

[100days-a-year]

Not sure I understand what you mean by long term exposure. Oxygen exposure on the order of minutes to hours can have important negative health consequences ranging from seizures, to pulmonary toxicity (e.g. inflammation of the respiratory membranes), to systemic inflammatory responses from oxidative stress. Seizing underwater obviously has some serious consequences. That aside, however, the negative effects of prolonged/high PO2 exposure are fairly short lived. In addition, there is some evidence that pure O2 exposure can have some beneficial short-term effects of reducing inflammatory responses to micro bubble formation (hence one reason why DCS patients are treated on O2).

Oxygen Toxicity and Special Operations Forces Diving: Hidden and Dangerous. - PubMed - NCBI

Yeah,the chance of osteonecrosis and permanent lung damage doesn't sound high but it's there.
PubMed is the place get the scoop on this stuff if you're interested either way.