Nitrogen Absorbtion at 2-3' mark?

[Driznik]

A fellow diver in my office just asked an interesting question - at least it was interesting to me.

With this David Blaine stunt in NYC, is he absorbing nitrogen even though he's only 2-3' underwater?

This gentleman was a marine biology major who did some 10' reef surveys as part of his course work. Because they gave him special tables for 10' during those surveys, he figured there must be some absorbtion even if you're only a few feet under.

I did a quick search here and on google, but I couldn't find anything.

D

 

[GDI]

The moment your body has any increased pressure on it then what is the norm there is an absorbtion of nitorgen. At only 2-3 ft the time limits are so large that a diver would need hours and days before significant amounts of nitrogen were of concern. Now No body can predict who will and who will not get bent and under what conditions this will occur at. depth is only one aspect of the DCS concern. Thge depth of 3 ft is only 1.09 ata and not very great. I did not see the stunt but I believe he was breath holding and not breathing compressed gases

 

[Diver Dennis]

If I'm not mistaken GDI, the breath holding part is after more than a week in a water filled sphere.

 

[Don Burke]

Any increase in pressure causes an increase in gas loading.

However, the deco programs I have fiddled with seem to think that a person fully saturated at about ten to thirteen feet can make a direct ascent to the surface with no ill effects.

I would not try that, but I would have no problem going from fully saturated at three feet to the surface. That would be less change than an ascent from the surface to a few thousand feet, something pilots do every day.

 

[wedivebc]

The Haldanean model allows you suface with less than 2ata gradient. That means all tissue saturated at <33 fsw. Other models have backed away from that but the chance of getting bent from a 3' dive is practically zero.

 

[spectrum]

At those depths and deeper at the beginning of a dive my computer's NDL is maxed out at 9:59.

Pretty low risk diving.

Just remember that lung over expansion can still be an issue so come up slow and breathing.

Pete

 

[curtmdavis]

At those depths and deeper at the beginning of a dive my computer's NDL is maxed out at 9:59.

Pretty low risk diving.

Just remember that lung over expansion can still be an issue so come up slow and breathing.

Pete

:lol:

from 2 feet!?!?

 

[spectrum]

:lol:

from 2 feet!?!?

Well he said 2-3 and 4 feet it is a real posibility so it seemed prudent to make the distinction between absorbtion and expansion.

Pete

 

[1_T_Submariner]

My computer doesn't even read until 4 feet above that it thinks you are on the surface.

 

[elcameroon]

I will give it a try using the law of partial pressures. At the surface we breathe a mixture of gas that is roughly 21% Oxygen and 79% Nitrogen. There are additional trace elements but lets keep it simple. 3' is 12/11's atmospheres of pressure = 1.091 ata. That mean's that Mr. blaine is breathing the equivalent of 86.181% Nitrogen.

While I do not have any tables or means of calculating off-gas because they are all theoretical anyway. I would venture a guess that Mr. Blaine would be able to maintain that depth indefinitely without negative reprecussions.