Does any computer manufactures post oxygen half times?
It is my understanding that oxygen has a single dive limit and a 24 hour limit and that half times are considered for elimination but not used for the calculation of a 24 hour limit.
If you are talking about the 24 hour limit it is like a cup and once you put some in it is always in until 24 hours has passed then it is not there anymore, so there are no half times to consider.
Doppler has a good article here;
Daily Limits for CNS Oxygen Toxicity | Doppler's Tech Diving Blog
You are not entirely correct. The NOAA table was designed to be used as a 24 hour exposure, as you point out. Steve Lewis (Doppler,you would likely enjoy his books) prescribes to this method to track oxygen exposure. However, there is an oxygen tissue elimination half life, most often said to be 90 minutes. This makes intuitive sense, similar to nitrogen elimination when the concentration gradient is downhill.
Some manufacturers use 24 hour exposure without an elimintion half life like my Oceanic computers. Some manufacturers use an oxygen elimination half like Scubapro and others. See the attached section form page 40 of the Luna owners manual:
The CNS O2 clock increases when the
oxygen partial pressure is higher than
0.5bar, and decreases when the oxygen
partial pressure is lower than 0.5bar. Hence,
while on the surface breathing air you will
always be decreasing the CNS O2 clock.
During the dive, the depth at which 0.5bar
is reached for various mixes is as follows:
Air: 13m/43ft
32%: 6m/20ft
36%: 4m/13ft
So, all I want to know from Scubapro is what oxygen elimination half life they use, really not a difficult question
Good diving, Craig
