Is it really worth the risk?

[Father]

I don't understand [-]guns[/-] rebreathers and I don't own a [-]gun[/-] rebreather so I don't think anyone should have one and the government should ban them so nobody else dies from using them.

I know very little about rebreathers but I'm going to give my input anyway because it's a discussion forum and well worded opinions are apparently an important factor in swaying someone's decision to do something. :diver:

I'd definitely agree that the risk is directly proportional to the comfort and more importantly skill level of the person using one.
The quality, assembly, operation, and maintenance of the equipment is also a critical factor in the level of risk you have of a catastrophic failure.

 

[Taliena]

You, or your current breathing gas?

LOL. I hope that I breathe now some normoxic air while sitting behind a computer (I didn't analyse the gas I am breathing now). But I know in some of my stages are hypoxic and hyperoxic gases.

 

[boulderjohn]

LOL. I hope that I breathe now some normoxic air while sitting behind a computer (I didn't analyse the gas I am breathing now). But I know in some of my stages are hypoxic and hyperoxic gases.

Well, I am sitting at a computer right now, but I am breathing a hypoxic mix.

When I set my computer to air for local diving (Or just plain breathing, I guess), it warns me that I am breathing a dangerously hypoxic mix. That's in my house in Boulder, Colorado. If I took it up to the mountains to an even higher altitude, it would really get upset.

 

[HIGHwing]

Admittedly, my idea got derailed. I was going to write a lengthy post about how the CCR diver should stop trying to be a physician underwater and more of a diver. There is an argument to be made that *if* you are above your intended Set Point you are hyperoxic (you're experiencing MORE oxygen than intended); below your indended Set Point you are hypoxic (you're experiencing LESS oxygen than you intended). If you choose to apply definitions to the terms hyperoxic/hypoxic specific to the diving context and avoid trying to be an on-the-spot M.D. self-prescribing oxygen dosages in ranges that are essentially untested lower/upper limits (for you on a specific dive) it forces you to rethink acceptable deviation from your intended PO2/Set Point. If we accept and apply those definitions we can prescribe an action a diver can take to remedy the current PO2 to match the intended SP.

Anyway, it didn't really come together. Sorry for the distraction.

All this really comes back to situational awareness, but I thought it would be interesting.

 

[PfcAJ]

Well, I am sitting at a computer right now, but I am breathing a hypoxic mix.

When I set my computer to air for local diving (Or just plain breathing, I guess), it warns me that I am breathing a dangerously hypoxic mix. That's in my house in Boulder, Colorado. If I took it up to the mountains to an even higher altitude, it would really get upset.

To be accurate, you're breathing a normoxic mix (21%) at a reduced atmospheric pressure.

 

[Dr. Lecter]

To be accurate, you're breathing a normoxic mix (21%) at a reduced atmospheric pressure.

Which comes back to my point about HIGHwing's question: does he want to know if the diver is hypo/hyperoxic, or just whether what they're breathing is one of those? boulderjohn might, if he went high enough, himself become hypoxic...the surrounding air would not.

 

[HIGHwing]

Which comes back to my point about HIGHwing's question: does he want to know if the diver is hypo/hyperoxic, or just whether what they're breathing is one of those? boulderjohn might, if he went high enough, himself become hypoxic...the surrounding air would not.

Let's go with the breathing gas.

 

[boulderjohn]

To be accurate, you're breathing a normoxic mix (21%) at a reduced atmospheric pressure.

Sure, but that it a technicality. It's the same Dalton's Law equation used to determine safe O2 levels in all diving. In theory, what I am breathing right now as I type will not support life.