Mailing List Archive

Mailing List: techdiver

Message Display

At Georges request I will repost the o2 tracking info for those who are 
following this
Tom
Oxygen % tracking is derived based on work by Donald (read oxygen and 
the diver) Dr. Bill Hamilton and numerous other references.
IANTD has a table it circulates that allows calculation of the % risk. 
A value of 100% represents the total SAFE exposure for the average 
population. The IANTD table is slightly more conservative than the OLI 
limits produced by Dr. Hamilton and Randy Bohrer, as the IANTD table is 
linear and provides additional consevatism on the risk at higher po 
2's.

The limits that the table are derived from are.
PO 2 in ata   CNS5/min
1.82           100
1.80            50
1.70            10
1.65             6.25
1.62             5.00
1.60             2.22
1.56             1.19
1.50             0.83
1.46             0.74
1.40             0.65
1.30             0.56
1.20             0.47
1.00             0.33
0.60             0.14

example a dive has a bottom exposur of 70 minutes at a po 2 of 1.30 
ata.

                                                           70 x 0.56 =
on deco 
3 minutes at p0 2 of 1.6 ata at a deep stop                  3 x 2.22
5 minutes at a po 2 of 1.5 ata                               5 x 0.83
10 minutes at a po 2 of 1.4 ata                             10 x 0.65 
20 minutes is spent at a po 2 of 1.6 ATA. at a shallow stop 20 x 2.22 = 
36 minutes at a po 2 of 1.3 ata                             36 x 0.56

If you total this it will equal the total CNS % of the dive.

For deep air diving just for fun run a 20 minute 240 foot profile with 
oxygen deco. It may make you reconsider your risk benefit.          

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]