Posted by MHK on April 03, 2000 at 12:38:36:
In Reply to: Re: Nitrox Safety Margins posted by Wayne on April 02, 2000 at 19:04:11:
I have seen them, only right now I can't place my hands on the URL. They were basically tests conducted in a chamber by Navy personell and they involved card and memory games and a few mathematical equations. I'll try to find the URL. But the basic premise is that in the area you are describing the 85' area, it's much like the guy who has 2 beers and swears he is fine. It's that subtle narcotic area. At the 100' - 130' range the narcotic effect is more noticeable.
I'm sure you are familiar with the formula below but for those that are not to calculate the EAD or Equivalent Air Depth use this formula:
EAD= | FN2(.74) *( depth + 33 ) |
|------------------------- | - 33 = EAD
| .79 |
So for example, if you were diving a EANx 36% to 85' you would solve for the above as follows:
.74 * (85' + 33)
----------------- = 110.53 - 33 = 77.53
So if you were diving a 36% Nitrox mix at 85' you would have the clear head as if you were diving an air mix to 78'.
And as you say you do not dive much deeper than 85' where you play so the OxTox concern that the anti-nitrox crowd likes to trot out as a scare tactic is really inapplicable to your type of diving.
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