Mailing List Archive Mailing List Archive
Hi all,
I have recently done the IANTD Deep Air course. Part of the theory covered was
CNS Oxygen toxicity and the method of the "CNS clock" for calculating oxygen
exposure for a given dive profile.
What is not clear in the manual is how this is extended to multiple dives
during a single 24 hour period. The NOAA limits specify exposures for
both single dives and total exposure in a 24 our period.
The CNS clock method only talks about single exposures.
My supposition is that you could extend the CNS clock method to the 24 hour
limits and thus effectively have two independent clocks (one for single exposure
and one for the cumulative 24 hour exposure), both of which must remain
below 100%.
It also seems to me that the longer the surface interval between dives,
the less the risk of cumulative CNS toxicity and hence that some concept
of "repetitive group" could be applied to CNS toxicity in a similar way
to inert gas loading.
Can anyone provide any good references to oxygen toxicity that might provide
me with a little more insight into these issues ?
Note: - The above comments are all related to CNS Oxygen toxicity (Paul-Bert
effect), NOT pulmonary toxicity (Lorrain-Smith effect).
- The interest in the daily limit calculations is of more theoretical
interest than practical as it would take some rather heroic diving
to get close to the daily limits!
Thanks for any input.
David.
______________________________________________________________________________
David Giddy, | Voice: +61 3 253 6388
Telstra Corporation, | Fax: +61 3 253 6144
P.O. Box 249, Rosebank MDC, 3169, AUSTRALIA | Internet: d.giddy@tr*.oz*.au*
------------------------------------------------------------------------------
Navigate by Author:
[Previous]
[Next]
[Author Search Index]
Navigate by Subject:
[Previous]
[Next]
[Subject Search Index]
[Send Reply] [Send Message with New Topic]
[Search Selection] [Mailing List Home] [Home]