APPD Appendix D 97
Appendix D
NOAA Oxygen Exposure Limits
PO2 (atm)
Maximum
Single
Dive Limit
(minutes)
Maximum
24-Hour
Limit
(minutes)
1.60 45 150
1.55 83 165
1.50 120 180
1.45 135 180
1.40 150 180
1.35 165 195
1.30 180 210
1.25 195 225
1.20 210 240
1.10 240 270
1.00 300 300
0.90 360 360
0.80 450 450
0.70 570 570
0.60 720 720
Figure D-10 NOAA Oxygen Exposure Time Limits.
The table gives the limits for a single
dive exposure to various PO2 levels and
for exposure during any 24-hour period.
(NOAA Diving Manual, 4th edition, 2001).
Oxygen partial pressures between 1.4
ata and 1.6 ata are shaded.
Oxygen Percentages for Best Mix
PO2 1.2 1.3 1.4 1.5 1.6
msw fsw
12 40 40% 40% 40% 40% 40%
14 45 40% 40% 40% 40% 40%
15 50 40% 40% 40% 40% 40%
17 55 40% 40% 40% 40% 40%
18 60 40% 40% 40% 40% 40%
20 65 40% 40% 40% 40% 40%
21 70 40% 40% 40% 40% 40%
23 75 37% 40% 40% 40% 40%
24 80 35% 38% 40% 40% 40%
26 85 34% 36% 39% 40% 40%
27 90 32% 35% 38% 40% 40%
29 95 31% 34% 36% 39% 40%
30 100 30% 32% 35% 37% 40%
32 105 29% 31% 33% 36% 38%
33 110 28% 30% 32% 35% 37%
35 115 27% 29% 31% 33% 36%
36 120 26% 28% 30% 32% 35%
38 125 25% 27% 29% 31% 33%
40 130 24% 26% 28% 30% 32%
Figure D-11 By selecting the planned maximum
depth and the maximum oxygen partial
pressure (usually 1.4 ata), the best
oxygen percentage for the nitrox mix is
easily established. Although percentages
higher than 40% are obtained by
calculation, this table shows EAN40
as the highest oxygen mix used in
recreational nitrox diving.