100m air dive & workup, PG

[DevonDiver]

....but you'll find plenty of old bald divers.

 

[Kevrumbo]

I've heard that speculation before. Has anyone seen any sort of data to support that speculation, or is it just totally SWAG?

No direct data . . .but there are indirect anecdotes about extreme pO2 exposure as a contingency. . .

(i.g. PO2 of 2.4 for 10min -->100m on deep air)

 

[Lobzilla]

No direct data . . .but there are indirect anecdotes about extreme pO2 exposure as a contingency. . .

(i.g. PO2 of 2.4 for 10min -->100m on deep air)

just don't make it a habit to use plan "C" as plan "A". Especially not with phenomena where both the predictability and the survivability is low.

 

[Lobzilla]

BTW: This thread illustrates nicely what a wonderfully tolerant place the dive 'industry' is.

Can you honestly imagine a race car driver forum where people discuss how many drinks you should have before a race and what your 'work up' training is?

Can you imagine glider pilots discussing how long you should fly in a mountain wave without oxygen and how you work yourself up to the edge of mental incapacitation?

Welcome to diving, where you can proudly admit that you do not give a rat's tail about your cognitive capacity.

 

[Centrals]

I was under the impression that the oxygen in air becomes toxic after 50m .... what happened to that? Do the laws of physics work differently in the Philippines?

I am not really sure if there is known LD-50 for O2 at various depth.

Mark Andrew did his 150m air dive also in PG.

 

[rjack321]

Welcome to diving, where you can proudly admit that you do not give a rat's tail about your cognitive capacity.

Before, during, or after the dive?

 

[rjack321]

I've heard that speculation before. Has anyone seen any sort of data to support that speculation, or is it just totally SWAG?

GeneH has posted a few references to this on TDS in the past. This thread would not be a place I'd expect to see him or repost legitimate information.

 

[Cave Diver]

GeneH has posted a few references to this on TDS in the past. This thread would not be a place I'd expect to see him or repost legitimate information.

Yeah, after a couple of the other references I was gonna start a thread on it elsewhere, but have been too lazy to yet.

 

[Kevrumbo]

GeneH has posted a few references to this on TDS in the past. This thread would not be a place I'd expect to see him or repost legitimate information.

Rubicon Research Repository: Item 123456789/1313
(no files, articles or data checked in with abstract link though)

Abstract: INTRODUCTION: The greatest risk in closed-circuit oxygen diving is of central nervous system (CNS) oxygen toxicity. There are disagreements as to the effect of inert gas, and there are no comprehensive data on the quantitative effect of inert gas[as of this date]. The upper oxygen pressure allowed in diving with oxygen enriched air has been set by NOAA and ANDI at 162 kPa, which is lower than the limit set for pure oxygen diving. The purpose of the study was to quantify the effect of inert gas and oxygen pressure on CNS oxygen toxicity. . ,

DISCUSSION: The general effect of the PN2 is to reduce the latency to CNS oxygen toxicity. However, rats showed prolongation of the latency at a specific PN2, mainly in the region of 200 kPa. It is suggested that rats sensitive to nitrogen narcosis will exhibit prolongation of latency, until HPNS effect that facilitates oxygen toxicity takes over. nitrogen narcosis, HPNS, oxygen toxicity, diving. See J Appl Physiol. 2005 Jan;98(1):144-50. for updated article.

http://archive.rubicon-foundation.org/dspace/handle/123456789/2445

While increasing the inert gas pressure, the latency gradually shortened, reaching the lowest values in mixtures of 5 ATA oxygen and 3 ATA of either inert gas [He & N]. On further increase in the inert gas pressure up to a total ambient pressure of 10 ATA [90msw], the latency returned to control (pure 5 ATA oxygen) values. No difference was found between nitrogen and helium of equal partial pressures. These findings suggest that the risk of CNS oxygen toxicity in gas mixtures is not determined solely by the PO2, and even a relatively low pressure of inert gas can contribute to the imminence of hyperbaric-oxygen-induced seizures.

Data-mine this thread if y'all want, and find something definitive:
http://archive.rubicon-foundation.o...n+toxicity,+deep+air,+nitrogen+buffer&start=0

 

[Tortuga68]

There's also this: The Rubicon Foundation: RRR Suggested Reading List

This thread would not be a place I'd expect to see him or repost legitimate information

Yet you've read every post in it haven't you