U.S. Navy Diving ManualVolume 2
Partial Pressure Mixing with Air. Oil-free air can be used as a Nitrogen
source for the partial pressure mixing of NITROX using the following
Prior to charging air into a NITROX bottle, the NITROX mixing
technician shall smell, taste, and feel the oil-free air coming from
the compressor for signs of oil, mist, or particulates, or for any
unusual smell. If any signs of compressor malfunction are found,
the system must not be used until a satisfactory air sample has been
Prior to charging with oxygen, to produce a NITROX mix, the
NITROX-charging technician shall charge the bottle to at least 100
psi with oil-free air. This will reduce the risk of adiabatic compres-
sion temperature increase. Once 100 psi of oil-free air has been
added to the charging vessel, the required amount of oxygen should
then be added. The remaining necessary amount of oil-free air can
then be safely charged into the bottle. The charging rate for
NITROX mixing shall not exceed 200 psi per minute.
Mixing contaminated or non-oil free air with 100% oxygen can result in a
catastrophic fire and explosion.
Figure 10-3. NITROX O2 Injection System.
NITROX Storage Bank
Oil-Free H.P. Compressor
Gas Mixing Coils
Oxygen Injection System