NOTE: Remember you are dealing with high-
-pressure gas. Before attempting to recharge any
extinguisher, you should become thoroughly
acquainted with the recharging pump and the
methods of recharging. Carefully read the instruc-
tions that pertain to the recharge pump and be
sure all connections are tight at all times.
C O2 CYLINDERS AND SAFETY DISC
Carbon dioxide cylinders should be charged
with bone-dry carbon dioxide. Extreme care
must be taken in the charging, weighing, sealing,
and testing of cylinders.
The safety discs of the cylinders are painted
various colors to identify the pressure at which
they will rupture. The correct color disc must be
used in every case. All cylinders are manufactured
in accordance with the requirements of the
Interstate Commerce Commission (ICC) as set
d o w n b y t h e B u r e a u o f E x p l o s i v e s . T h e s e
requirements specify that the cylinder be tested
to five-thirds of its normal working pressure and
that the normal working pressure be stamped on
the cylinder immediately following the letters
ICC3A. We refer to this procedure as hydrostatic
testing. Common cylinder stampings and the
corresponding test pressures are as follows:
ICC 3A 1800
ICC 3A 2015
ICC 3A 2205
White or red
ICC 3A 2300
White or red
You should never use a disc in a valve where
it would be working in connection with a different
type of safety disc retainer. Never trim a safety
disc to fit a valve other than the one for which
it was intended.
You will find similar markings on the shoulder
of every cylinder.
ICC 3A 1800
W. K. & Co.
An explanation of these marks follows:
ICC 3A 1800 signifies the specific ICC test
procedure followed. The number 1800 indicates
the service pressure.
221974 is the cylinder serial number. Some
cylinders have one or two letters as part of the
serial number. (The U.S. Navy also assigns one
of their numbers to all cylinders they purchase.
This number has the letters USN accompanying
it.) The letter H in a shield is the designation mark
of the accredited ICC inspecting laboratory that
supervises our tests.
The letters W. K. & Co designate the manufac-
turer of the cylinder.
The numbers 10-84 mean that the cylinder was
tested in October of 1984 and that its next test
will be October 1989.
Before any cylinder is recharged, the date must
be checked; if more than 5 years has elapsed, the
cylinder must be retested hydrostatically. The
date of the retest is then stamped on the cylinder
directly under the original date. This new date is
the one against which future checks should be
Remember you are dealing with high-pressure
gas. Before recharging any cylinder, you must
become thoroughly familiar with the proper
procedure for recharging.
When you handle or ship cylinders, the
shipping cap should always be assembled on the
cylinder. On cylinders where this is not possible,
the cylinder should be carefully crated.
Be thoroughly familiar with these procedures
before you attempt to recharge any cylinder. A
few minutes spent on becoming familiar with the
procedure may prevent an accident involving
injury to personnel or damage to equipment.
The PR is not normally tasked with the
responsibility of recharging fire extinguishers and
engine fire bottles.
H o w e v e r , y o u m a y be
assigned to an AIMD that supports aircraft that
require winterizing of CO2 cylinders.
All carbon dioxide portable fire extinguishers
installed in aircraft and all aircraft carbon
dioxide built-in engine fire extinguishers are
serviced to operate throughout the temperature
range of 65°F to 160°F. The extinguishers are
supercharged with the addition of 200 psi of dry,
oil-free nitrogen. This servicing of extinguishers
is done in connection with the U.S. Air Force
winterization program. Extinguishers charged to
meet this winterization requirement are identified
by a yellow dot, three-fourths of an inch in
diameter or larger, on opposite sides of the
cylinder. Extinguishers so marked are winterized