CHAPTER 8
CARBON DIOXIDE
Learning Objective: Upon completion of this chapter, you will be able to
describe, inspect, recharge, and perform maintenance on carbon dioxide
cylinders and transfer units.
Carbon dioxide is a heavy, colorless
gas. The chemical symbol for carbon dioxide
is CO2. You will find that most people
use this symbol when referring to carbon
dioxide.
C O2 doesn’t burn and does not sup-
port combustion; therefore, it makes a fine
fire-fighting agent. It is strongly recommended
for use on electrical fires.
The servicing
of fire-fighting equipment is not part of the
PR rate, and so this text does not cover
fire extinguishers.
As a PR you deal with life raft and life
preserver CO2 cylinders, which you weigh,
recharge, and repair.
Carbon dioxide is ordinarily procured from
local commercial sources. It is stored in standard
supply cylinders that contain 50 pounds of carbon
dioxide when full.
Before learning how to recharge CO2
cylinders, you should be familiar with the
following information:
In its gas form, carbon dioxide is 1.53
times heavier than air.
C O2 g a s c a n be
converted into a liquid by applying pressure
to the gas. With as little as 600 psi at
a temperature below 88°F, the CO2 g as
can be converted into a liquid and stored
in that state until it is subjected to the
outside atmosphere. By opening the cylinder
valve and letting the carbon dioxide escape
into the atmosphere, you cause a rapid drop
in pressure. As the CO2 escapes through
the small opening, it forms carbon diox-
ide snow. This snow, when compressed into
blocks or cubes, is known as dry ice.
At atmospheric pressure, dry ice will re-
main at – 110°F, directly evaporating into CO2
gas. CO2 exists as a liquid only when under
pressure.
Whenever you are working with CO2
in any of its three stages—gas, liquid, or dry
ice, you should be aware that small percent-
ages of CO2 in the air causes tiredness
and perhaps headaches. Experiments have
shown that a 3-percent concentration in the
air doubles your breathing effort, 5 percent
causes panting, 8 percent causes marked dis-
tress, and 10 percent causes unconsciousness
very quickly.
Treatment of exposed personnel includes
removing them from the CO2-laden atmos-
phere, artificial resuscitation, administering
oxygen, and keeping the patient warm.
CO2 RECHARGE EQUIPMENT
Carbon dioxide recharge equipment is
manufactured for the Navy by several dif-
ferent companies. The two most widely used
units are those manufactured by the C-O-
TWO Company of Newark, New Jersey (do
not confuse this company with the chemical
symbol CO2) and the Walter Kidde Company
of Belleville, New Jersey.
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