Figure 5-1 compares the maximum bottom times
for single dives breathing air, NOAA Nitrox I, and NOAA
Nitrox II. Clearly, there are considerable advantages to
breathing nitrox.
NAUI ENRICHED AIR NITROX TABLES
NAUI has chosen to use the U.S. Navy Dive Tables as
the basis for its standard EAN32 and EAN36 Dive Tables.
The NAUI RGBM Nitrox tables are a different case: They
are based on the Reduced Gradient Bubble Model algorithm
rather than the U.S. Navy Tables and are also nocalculation
tables. They will be discussed separately later.
The NAUI Nitrox Dive Tables use the same format
and have the same safety margin factors as the NAUI Air
Dive Tables. They present all shallow dives as though to
a depth of 12 meters (40 feet), and they require 24 hours
to fully offgas residual nitrogen.
The NOAA Abbreviated EAN32 tables follow the
NAUI EAN32 tables exactly. However, NAUI EAN36 tables
have certain safety factors not incorporated in the NOAA
version of the tables, and they have lesser maximum
dive times than the NOAA Nitrox II tables for dives to 12,
15, and 21 meters (40, 50, and 70 feet) with correspondingly
lower end-of-dive letter groups. NAUI Nitrox Dive
Tables also place the precautionary safety stop at 5
meters (15 feet); the NOAA Nitrox Tables have the stop at
3 meters (10 feet).
Establishing maximum dive times, finding end-ofdive
letter groups, determining surface interval credit,
and planning repetitive dives are accomplished exactly
as with NAUI Air Dive Tables. Table 1: End-of-Dive Letter
Group; Table 2: Surface Interval Time Table; and Table
3: Repetitive Dive Time Table each are formatted and
used as with the air table. If you need to review the use
of dive tables, you should revisit your basic scuba text.
How to use NAUI Dive Tables can also be found on our
web site at www.naui.org/tables.aspx.
On the NAUI Nitrox Tables, Table 1 and Table 3
each have some additional information. They show the
oxygen partial pressure for each depth (a column to the
left on Table 1 and a top row on Table 3). Information
for dives that exceed a PO2 of 1.4 atmospheres is shaded
FIGURE 5-2: NAUI EAN32 DIVE TABLES
light green to make the planner aware that these dives
exceed the normal oxygen exposure limit for recreational
nitrox diving. The maximum depth on both tables is
NAUI Nitrox Diver
56 Dive Tables and Dive Computers
FIGURE 5-3: NAUI EAN36 DIVE TABLES