The NOAA CNS Oxygen Exposure Limits chart is used for avoiding CNS Oxygen Toxicity problems while conducting multiple dives on one day. The first column represents the maximum oxygen partial pressure exposure in atmospheres.

Aug 15, 2014 · When diving long and deep it is important to track your CNS and OTU exposure. Here is a brief overview of what they are and how to calculate them. What is CNS Oxygen Exposure? Although it is possible to reach CNS Oxygen Toxicity by going below the maximum allowable depth of your breathing gas, you…

Mar 23, 2015 · You can see that even small increases of PPO2 above 1.6 cause the allowable exposure time to decrease dramatically. Above a PPO2 of 1.65 ata, the CNS rate increases at a fixed rate of 1% every 4 seconds! This is fast, but is derived from the widely used NOAA values.

Feb 10, 2009 · DSAT tells you to follow 1.4 and 1.6, and NOAA CNS is just an additional check on top of OTU limits for pulmonary toxicity, despite being called CNS. IANTD is a little more circumspect, and I’ve formed the opinion that it was designed to manage both forms of toxicity.

The National Oceanic and Atmospheric Administration (NOAA) recommends a more conservative 180 minutes at 1.3 ATA for normal exposures and 240 minutes only for exceptional exposures. The Professional Association of Diving Instructors (PADI) has proposed a limit of 1.4 ATA for open-circuit nitrox scuba diving.

Oxygen exposure tracking is important in technical and rebreather diving. Use these tables to determine the Percent CNS O2 clock or Oxygen Toxicity Units (OTU) for any time exposure to PO2's from 0.60 ATA to 1.60 ATA in 0.05 ATA increments.

Oct 18, 2006 · The hazards of CNS oxygen toxicity are easily avoided by ensuring that your dive profiles don't violate the NOAA limits. Set your PO2 at 1.6 (less for longer dives), watch your computer's display of dose accumulation, and do not exceed the maximum depth limit for your nitrox mix. Signs and Symptoms of CNS Oxygen Toxicity. Facial pallor. Sweating

Aug 15, 2019 · It seems, everybody is using essentially the same table of values published by NOAA, with the time being infinite for pO2 < 0.5 bar, then starting with 720 minutes and then steeply decreasing to 45 minted at a pO2 of 1.6 bar where the table ends as you are not supposed to breath a pO2 above that value.

Apr 8, 2019 · The best reference that I have found is the NOAA Divers Manual, Chapter 3 which gives % saturation calculations for various PP02s in 5 minute intervals. This would allow one to calculate Oxygen saturation in multi-level and repetitive dives manually.

Jul 16, 2012 · Turns out according to NOAA you're allowed 1440 OTUs in a day (O2 at 1.0 ATA for a 24 hour period). The recommended maximums in the tables come from leaving enough OTUs to tolerate a USN TT6 recompression session. A TT6 is approximately 600 OTUs; 1440-600 = 840, rounded up to 850 for the first day.