Q10-14. Which of the following activities can
escape ports. If a cylinder becomes heated above the
perform a hot nitrogen purge on a LOX
melting point of the fusible metal, the pressure in the
cart?
cylinder will increase and the frangible disc will
rupture, venting the gas to the atmosphere. To protect
1.
An organizational-level activity
the valves of gas cylinders, threaded valve protection
2.
An intermediate-level activity
caps screw onto the cylinder neck ring.
3.
A depot-level activity
4.
A Navy contracted activity
Identifying Markings
GASEOUS OXYGEN
Gas cylinders used by the Navy, Army, and Air
Force carry standard identifying features, in addition
LEARNING OBJECTIVES: Identify the
to markings required by the Interstate Commerce
components of gaseous oxygen cart systems.
Commission. In the past, many injuries occurred and a
Identify procedures for inspecting, checking,
great deal of damage was caused by mistaking one gas
cleaning, testing, and adjusting gaseous oxygen
cylinder for another. To remedy this situation, a
cart system components. Identify procedures
for troubleshooting gaseous oxygen cart
national program was started to make it almost
systems. Identify procedures for repairing,
impossible to mistake one type of cylinder from
removing, and replacing gaseous oxygen cart
another. Under this program, the identifying features
system components.
used by the Armed Forces consist of color coding the
cylinders, stenciling the name of the gas along two
There are two types of gaseous oxygen used in the
sides of the cylinders, and affixing decals to the
Navy: aviators' breathing oxygen (99.5% pure) and
shoulders of cylinders.
technical (or industrial) oxygen. Technical oxygen
may have a small moisture content that can freeze at
The official color codes for marking compressed
high altitudes, so it isn't suitable for breathing aboard
gas cylinders is given in the current MIL-STD-101.
aircraft Gaseous oxygen is colorless, odorless, and
Aviators' breathing oxygen cylinders are green with
tasteless.
one white band. Technical oxygen cylinders are solid
green with no bands.
GAS CYLINDERS
Gas cylinders are made of high quality steel.
WARNING
Cylinders for high-pressure gases, such as oxygen and
Do not rely solely on color codes for identifying
nitrogen, are seamless. Cylinders used for
the contents of gas cylinders. Exact identification
low-pressure gases, such as acetylene, may be welded
of the contents of a cylinder can only be made from
or brazed. All cylinders are carefully tested at
the name stenciled on the cylinder and from the
pressures above the maximum permissible charging
affixed decals.
pressure.
Safety Devices
Navy-owned gas cylinders are further identified by
All gas cylinders have safety devices in their
indented serial numbers, preceded and followed by
valves, in their shoulders, in the bottoms of the
letters in the following pattern:
cylinders, or in a combination of these places. One type
of safety device is the fusible plug, which may be
U
U
described as a threaded hex head bolt with a center
SX618793S
filled with a fusible metal. If the cylinder is subjected
N
N
to high temperatures, the fusible metal will melt,
allowing the gas to vent to the atmosphere.
Navy serial numbers are also augmented by a
designated letter preceding the numerals. This letter
Safety caps with rupture discs are used in the
identifies the cylinder in respect to the specific gas
valves of cylinders that contain nitrogen and oxygen.
contained within. In the above example, the letter X
These caps have a frangible disc supported by fusible
identifies the cylinder as one that contains oxygen.
metal (contained in the safety cap), which blocks off
10-23
