dissolved in acetone, and are assigned Navy serial
CONSTRUCTION OF CYLINDERS
numbers on the volume basis. In other words, gases in
the liquid state are measured by weight, and those in
Gas cylinders are made of high-quality steel.
the gaseous state are measured by volume. Acetylene,
High-pressure gases, such as oxygen, hydrogen,
though dissolved in a liquid, is measured as a gas by
nitrogen, and compressed air are stored in cylinders of
volume.
seamless construction. Only nonshatterable
high-pressure gas cylinders may be used by ships or
Since 1 August 1944, Navy serial numbers have a
activities operating outside the continental United
designated letter placed before the numerals. This
States. Cylinders for low-pressure gases, such as
letter shows the type of gas carried in the cylinder.
acetylene, may be welded or brazed. All cylinders are
The lettering system assigns the following letters to
carefully tested, either at the factory or a designated
the gases:
processing station, at pressures above the maximum
permissible charging pressure.
A--Acetylene
The cylinders for most compressed gases are
M--Ammonia
shaped alike. However, cylinders for acetylene are
D--Carbon dioxide
shorter and of a larger diameter, as shown in figure
5-65.
K--Chlorine
All gas cylinders have safety devices either in the
E--Ethylene oxide
valve, in the shoulder, in the bottom of the cylinder,
H--Helium
or in a combination of these places. A threaded valve
protection cap screws on the neck ring and protects the
N --Nitrogen
valve.
J--Nitrous oxide
MARKING AND IDENTIFYING GAS
G--Aerosol
CYLINDERS
X--Oxygen
Gas cylinders are manufactured and maintained
P--Liquefied petroleum gas (propane, butane, and
according to the regulations of the Interstate
so on)
Commerce Commission (ICC). The ICC stipulates
S--Sulfur dioxide
that each cylinder be indented or stenciled with
F--Freon
prescribed identification markings. Cylinders larger
than 2 inches in diameter must be indented with serial
B--Carboxide
numbers. Therefore, cylinders exceeding 2 inches in
diameter, which are not assigned Navy serial numbers,
require manufacturer's serial numbers. No more than
R--Methyl chloride
500 cylinders are allowed in each lot manufactured.
Z--Compressed air
Requirements for ICC 8 (acetylene) and ICC 9
(aerosol dispenser) cylinders are exceptions to this
L--Ethyl chloride
requirement. ICC 8 cylinders of all sizes require serial
numbers and ICC 9 cylinders of all sizes are assigned
lot numbers. However, an unlimited number per lot is
V--Argon
authorized.
In addition to markings required by the ICC, gas
Navy-owned compressed-gas cylinders are
cylinders used by all three services--Navy, Army, and
indented with figures and letters. In addition to the
Air Force --have certain standard identifying
identifications required by ICC regulations,
features. So much injury and damage can be, and has
Navy-owned cylinders for gases in the liquid state
been, caused by mistaking one gas cylinder for
with a water capacity in excess of 15 pounds, or gases
another. Therefore, a national program has been
in the gaseous state with a volume in excess of 658
established to make it almost impossible to confuse
cubic inches, are identified by an indented Navy serial
cylinders. The identifying features used by the Armed
number. This number is preceded and followed by the
Forces in this program consist of using a color code
for painting the cylinders, stenciling the name of the
letters USN. Acetylene cylinders contain acetylene
5-41