NITROX diving can be performed using a variety of equipment that can be broken
down into two general categories: surface-supplied or closed- and open-circuit
scuba. Closed-circuit scuba apparatus is discussed in Chapter 17.
Open-Circuit Scuba Systems. Open-circuit scuba systems for NITROX diving
are identical to air scuba systems with one exception: the scuba bottles are filled
with NITROX (nitrogen-oxygen) rather than air. There are specific regulators
authorized for NITROX diving, which are identified on the ANU list. These regulators
have been tested to confirm their compatibility with the higher oxygen
percentages encountered with NITROX diving.
Regulators. IScuba regulators designated for NITROX use should be cleaned to
the standards of MILSTD 1330. Once designated for NITROX use and cleaned,
the regulators should be maintained to the level of cleanliness outlined in MILSTD
1330.
Bottles. Scuba bottles designated for
use with NITROX should be oxygen
cleaned and maintained to that level.
The bottles should have a NITROX label
in large yellow letters on a green
background. Once a bottle is cleaned
and designated for NITROX diving, it
should not be used for any other type of
diving (Figure 10-2).
General. All high-pressure flasks,
scuba cylinders, and all high-pressure
NITROX charging equipment that
comes in contact with 100 percent oxygen
during NITROX diving, mixing, or
charging evolutions much be cleaned
and maintained for NITROX service in
accordance with the current MILSTD 1330 series.
Surface-Supplied NITROX Diving. ISurface-supplied NITROX diving systems
must be modified to make them compatible with the higher percentage of oxygen
found in NITROX mixtures. A request to convert the system to NITROX must be
forwarded to NAVSEA 00C for review and approval. The request must be accompanied
by the proposed changes to the Pre-survey Outline Booklet (PSOB)
permitting system use with NITROX. Once the system is designated for NITROX,
it shall be labeled NITROX with large yellow letters on a green background.
MILSTD 1330.D outlines the cleanliness requirements to which a surfacesupplied
NITROX system must be maintained.
A NITROX system must not be used for air diving except in an emergency. Once
a designated NITROX system is used with air, it must be re-cleaned to MILSTD
1330 series prior to use with NITROX. An exception to this would be if the air
used in the banks is charged with an oil-free NITROX-approved compressor or if
the air meets the purity requirements of oil-free air.
