Initial Fire-Fighting Operations
In fire-fighting operations, you must first
determine the location and type of fire and then
determine the method of extinguishing the fire,
as shown in table 7-4. For complicated or
simultaneous fires, fog will serve in nearly every
situation. In case of a class C fire, first de-energize
all circuits where possible. Next, establish fire
boundaries by cIosing all doors, hatches, man-
holes, ventilation ducts, and other vents in the
area as practical and de-energize power as
CO2 Safety Precautions
You must be aware that the very qualities that
make carbon dioxide (CO2) a valuable ex-
tinguishing agent also make it dangerous to life.
When CO2 replaces oxygen in the air where
combustion cannot be sustained, there is no
respiration. Prolonged exposure to carbon dioxide
causes suffocation, very much as immersion in
water does when a person drowns. CO2 cannot
be seen or smelled. It gives no evidence of its
presence that can be recognized by the senses.
Since CO2 is heavier than air, it remains close to
the surface of the space in a deep or shallow pool,
depending on the amount of area covered and the
amount of CO2 used. When a portable carbon
dioxide extinguisher is used, there is practically
no breathing danger in the average compartment
because its 135 cubic feet of CO2 lies in a shallow
pool well below the usual breathing level.
When entering a compartment that contains
carbon dioxide (or any other harmful gas) in a
dangerous concentration, you must wear an OBA.
Except in an emergency, you should not open
a CO2 flooded compartment for at least 15
minutes after it has been flooded. This delay is
a precautionary measure to give all the burning
substances time to cool down below their ignition
temperature; this prevents reignition upon contact
Warn anyone who uses a carbon dioxide ex-
tinguisher that the snow will blister the skin
and cause painful burns if it is allowed to remain
on the skin.
Discharge of CO2 leads to a buildup of a static
electrical charge. You should keep the cylinder in
contact (grounded) with the metal structure of the
ship when discharging CO2.
Halon 1301 Hazards
The mechanism by which Halon 1301 ex-
tinguishes a fire is not thoroughly understood. The
phenomenon appears to be a physical/chemical
action that inhibits combustion. Halon 1301 has
the ability to extinguish both the flammable
liquid spill and spray types of fire. Halon 1301
decomposes upon contact with flames or hot
surfaces above 900°F (482°C). While this decom-
position allows the Halon 1301 to function
effectively, it also results in the formation
of several decomposition products, primarily
hydrogen fluoride and hydrogen bromide.
Fuel decomposition products, carbon monoxide,
oxygen depletion, heat, and smoke create person-
nel hazards. Personnel should not remain in a
space where Halon 1301 has been released to
extinguish a fire unless OBAs are worn. Although
personnel can be exposed to concentrations of 5
to 7 percent of Halon 1301 for up to 10 minutes
without danger to health, spaces should still be
evacuated upon accidental discharge.
If Halon 1301 is discharged where no fire
exists, several hazards may arise. For example,
noise from the discharge can be startling;
turbulence may be sufficient to move light objects;
direct contact with the vaporizing liquid may have
a strong chilling effect and can cause frostbite and
burns to the skin; and obscured vision may result
because of condensation of water vapor in the air.
If you are in a space where Halon 1301 is dis-
charged and vision is obscured, do not move
about until vision improves. Moving blindly could
result in injuries.
Preventing Spreading of Fires
In fighting a fire, you should secure any
breaches in bulkheads adjacent to the fire. Also,
be sure to cool adjacent bulkheads. Remove any
combustibles from nearby compartments or
render the compartments safe by one or more of
the following methods:
Cool or smother compartments with fog.
Fill compartments with CO2.
Flood compartments as practical.
Start postfire action while fire fighting is still
in progress. As the on-scene leader you should