Let me clarify several of the points that Alec was
making:
1.
While the standards for scuba air
require almost no oil, a very minimal is allowed. Only Class "E" air
used in the mixing of NITROX is no oil allowed. Small amounts of oil
will accelerate the deterioration of the LP and HP flexible hoses associated
with a SCUBA regulator.
2.
There are two primary reasons for
NO moisture in the air finally compressed into the SCUBA
cylinders:
a.
On swift release of air from a
SCUBA tank as in blowing ballast at depth in an emergency instead of motoring
to near the surface, the adiabatic cooling will occur within the tank
resulting in condensation. This moisture does not subsequently become
revaporized when the tank is later refilled. The accumulated moisture
will cause a hastened corrosion of the tank interior resulting in a failed
hydro or tank failure.
b.
If the gas expansion occurs under
low temperature ambient conditions, the moisture can freeze in the
1st or 2nd stages of the regulator that is surrounded by
air resulting in an uncontrollable free flow condition which can result in
rapid loss of tank pressure.
3.
SCUBA tanks available from AGA
are rated to 4,400 psi.
4.
Studies conducted in the 70s at
the University
of Rhode Island from that
99.9% of SCUBA tank failures due to corrosion were “soft” and not explosive
(i.e., the air slow leaked out of a pin hole). A catastrophic failure of
a SCUBA tank releases the energy equivalent to 10 pounds of dynamite.
Aluminum tanks have a variety of other reasons for catastrophic failure such
as overheating and brittle fractures forming in the neck due to poor forming
methods to name a few.
Respectfully,
Jay K. Jeffries
Ocean Engineer
Andros Is., Bahamas