nitrogen narcosis

[wedivebc]

Did I miss something here or what?
A certain training agency states in the tech manual that:
"Oxygen is twice as soluable as nittrogen; suggesting thatit is potentially more narcotic than nitrogren. This is offset somewhat by you body metabolizing oxygen however, so it doesn't appear to be nessasary to raise you END with enriched air compared to air"

Then this same agency in the SCR rebreather instructor outline states: "...higher than planned oxygen consumption will elevate nitrogen, creating more potential nitrogen narcosis at a given depth."

Is this a contradiction? Maybe I'm narked

cheers,

 

[MikeFerrara]

I don't know about the SCR end of it but the general consensus seems to be that O2 is just as narcotic as nitrogen.

 

[roakey]

Then this same agency in the SCR rebreather instructor outline states: "...higher than planned oxygen consumption will elevate nitrogen, creating more potential nitrogen narcosis at a given depth."

Is this a contradiction?

No. If you exert yourself on a constant mass SCR, for example, you will deplete the O2 faster than it's being replaced. So you scrub out the CO2, less O2 is put into the loop than is being consumed and the only gas left to "take up the volume" is N2, so the % of N2 in the loop increases.

I'm not an SCR diver and I don't play one on TV either.

Roak

 

[wedivebc]

No. If you exert yourself on a constant mass SCR, for example, you will deplete the O2 faster than it's being replaced. So you scrub out the CO2, less O2 is put into the loop than is being consumed and the only gas left to "take up the volume" is N2, so the % of N2 in the loop increases.

I'm not an SCR diver and I don't play one on TV either.

Roak

Right so which is it, increased nitrogen increases narcosis or oxygen and nitrogen both contribute the same amout to the narcosis? It has to be one or the other. Since both documents are published by the same agency they should agree right?

 

[Mako Mark]

Aparently CO2 significantly contributes to narcosis as well, I had a good discussion with MHK about that a couple of months ago on a thread about deep air diving.

 

[wedivebc]

Aparently CO2 significantly contributes to narcosis as well, I had a good discussion with MHK about that a couple of months ago on a thread about deep air diving.

I believe that is true. That may be why some people experience narcosis differently one dive to the next.

 

[MikeFerrara]

Aparently CO2 significantly contributes to narcosis as well, I had a good discussion with MHK about that a couple of months ago on a thread about deep air diving.

Narcosis and oxtox both.

 

[MikeFerrara]

Right so which is it, increased nitrogen increases narcosis or oxygen and nitrogen both contribute the same amout to the narcosis? It has to be one or the other. Since both documents are published by the same agency they should agree right?

I hate to say it. LOL but just because an agency printed it doesn't make it right.

I have heard that the PPO2 can run low for a given diluent but I wouldn't expect it to have a significant effect on the narcosis.

 

[SamDiver14]

No. If you exert yourself on a constant mass SCR, for example, you will deplete the O2 faster than it's being replaced. So you scrub out the CO2, less O2 is put into the loop than is being consumed and the only gas left to "take up the volume" is N2, so the % of N2 in the loop increases.

I don't mean to be dense but could you explain that a little more?

 

[jagfish]

Me too...
Also, this statement make me wonder about partial pressures. So, say the loop had gas at 1ATA (just for discussion). If this gas was composed of 3 components (O2, CO2 and N2), in equal amounts (once again for discussion), they would each have a partial pressure of 1/3 ATA.

However, if we scrubbed out all the CO2 (just for discussion) in a closed system, that would leave only the O2 and N2 taking up the same space. Would the total pressure in the system drop below 1ATA, and would the partial pressures of O2 and N2 remain the same? (making the pressure of the total system like .66 ATA, 1/3 ATA + 1/3 ATA?)