will remain a liquid under-normal atmospheric
Once converted into a liquid, oxygen will
remain in its liquid state as long as the temperature
is maintained below -297°F. The liquid has an
expansion ratio of about 862 to 1, which means
that one volume of LOX will expand about 862
times when converted to a gas at atmospheric
pressure. Thus, 1 liter of LOX produces about
862 liters of gaseous oxygen.
As already mentioned, the main dangers of
LOX are the extremely low temperature of the
liquid, its expansion ratio, and its support of
violent combustion. The liquid is nontoxic, but
will freeze (burn) the skin severely upon contact.
Use extreme caution not to touch implements
containing LOX unless gloves are worn. Without
gloves, bare skin would immediately stick and
freeze to the metal surface.
Personnel that could be exposed to accidental
spillage of LOX must wear a face shield, coveralls,
gloves, and oxygen safety shoes to prevent skin
and vision damage. Open gloves, low cut shoes,
trousers with cuffs, and similar improper clothing
that can form pockets capable of holding a
quantity of LOX in contact with the skin present
a severe hazard. All personnel handling LOX must
wear the protective clothing specified in the
protective clothing section of NAVAIR 13-1-6.4.
A greater danger than freezing is the
combustion supporting potential of oxygen. When
LOX is used, it is possible to build up high
concentrations of oxygen quickly. Many materials
such as cloth, wood, grease, oil, paint, or tar will
burn violently when saturated with oxygen,
provided an ignition source is supplied. A static
electric discharge or spark can serve as an igniter.
Once an oxygen-enriched fire is started, it is
virtually impossible to extinguish until the oxygen
supply is cut off.
An added danger exists if a combustible
material is saturated with oxygen at low
temperatures. Many materials, especially hydro-
carbons, tar, etc., will burn with explosive
violence when so saturated or subjected to very
mild shock or impact.
Extreme care must be taken not to splash or
spill LOX on clothing. When LOX come in
contact with cloth, an ideal and deadly situation
for a fire existsa fire that cannot be put out.
LOX by itself will not burn, but mixed with
the smallest amount of almost any material will
cause the liquid to boil and splash violently,
making combustion possible. If splashed out of
a container, LOX will break into many parts upon
contact with the floor\deck. It must be poured
slowly from one container to another to avoid
splashing, and to allow the gaining receptacle to
cool sufficiently without thermal breakage.
NEVER seal or cap the vent port of a
liquid oxygen system because liquid oxygen at
atmospheric pressure will generate up to 12,000
pounds of pressure if allowed to evaporate in a
sealed container or system that has no relief
Access to oxygen supply/storage areas should
be limited only to personnel familiar with proper
handling procedures. The area should be
adequately ventilated and free of any materials
that could present a fire hazard. All pressure-type
containers, plumbing, and pressure-relief devices
should conform to the applicable maintenance
manual and be kept in good repair. The vents on
LOX containers are designed to have a sufficient
flow capacity to carry away any oxygen that may
boil off in case of accidental loss of insulation.
Do NOT cap such vents or cause the opening to
be restricted in any way.
The pressure relief assembly in LOX system
storage vessels consists of a reseatable relief valve
and a rupture disc in parallel. The assembly is
designed so that the relief valve relieves first, with
the rupture disc acting as a safety backup in the
event the relief valve malfunctions or its relieving
capacity is exceeded.
LOX converters and servicing trailers should
be stowed or parked so that they are protected
from excessive heat and the direct rays of
sunlight as much as is practical. All LOX
should be segregated from containers of other
gases or liquids and all flammable materials.
Hydrocarbons such as oil and grease in the
xygen handling area could result in death, serious
injury, and property damage.
Smoking, open flames, or sparks are not
ermitted in any oxygen handling area. When
transferring oxygen, provide adequate ventilation
to prevent the formation of an oxygen enriched
Avoid spilling LOX on floors or deck areas.
In case of accidental spillage, ventilate the area.
Intentional drainage of LOX from a system or
container must be caught in a clean drain pan and
allowed to evaporate in a suitable open area that
will not present a hazard.
In the event that LOX is spilled on clothing,
separate clothing from skin contact immediately,