For a solid fuel to burn, it must be changed into a
When flammable liquids spill or leak from a
vapor state. This chemical action is known as
pressurized source, they will cover a large area,
pyrolysis and is defined as a chemical decomposition
release a great amount of vapor, and produce a great
due to the application of heat. This decomposition
amount of heat when ignited. One of the
creates a fuel vapor, which, mixed with oxygen,
specifications of flammable liquids is that they have a
produces a fire.
minimum flashpoint. Anytime a ship is refueled, the
Removal of any one of the three elements of the
fuel it receives is tested for both quality and for
fire triangle (heat, oxygen, and fuel) will extinguish a
flashpoint.
fire. A common method of attacking class ALPHA
fires is the application of water. The water cools the
Some flammables require special storage, often in
fuel below its ignition point, thereby removing heat
special lockers with temperature detection and
from the fire triangle and thus extinguishing the fire.
sprinkler systems installed. Some of the materials
On larger fires of this type, aqueous film-forming
stored in these lockers are paints, welding gases,
foam (AFFF) will be more effective than seawater. In
flammable cleaning solvents, and other materials. An
all such fires, other nearby combustibles (including
accurate inventory of hazardous materials stored in
unseen materials on the other side of that bulkhead)
must either be moved or kept cool to prevent further
such lockers should be readily available. Fuels for
spread of the fire.
portable fire-fighting pumps and special small boats
may sometimes be stored on the weather decks of the
CLASS BRAVO FIRE
ship.
A class BRAVO fire presents challenges not
Your ship's supply department can provide
encountered in other types of fires. This is because they
information about flammable materials (including
can be fueled by any of the flammable liquids stored
safety and handling precautions, hazards, and
aboard ship, including fuels, liquid lubricants, and
minimum flashpoints). The Material Safety Data
solvents. Class BRAVO fires may be extinguished with
Sheets (MSDS) have information on each individual
H a l o n , A F F F, p u r p l e - K p o w d e r ( P K P ) , o r a
hazardous product carried onboard ship.
combination of agents. The single most important step
in combating this casualty is to secure the source of the
CLASS CHARLIE FIRE
fuel.
A class CHARLIE fire is an energized electrical
One of the characteristics of a flammable liquid is
fire, and may be attacked with nonconductive agents
known as flashpoint, which is the lowest temperature at
such as carbon dioxide (CO2) or with low-velocity
which the liquid will give off sufficient vapor to form
water fog. Special care must be taken to maintain a safe
what is known as an ignitable mixture. When mixed
d i s t a n c e f r o m e n e rg i z e d e q u i p m e n t . T h e m o s t
with air at this minimum temperature, this vapor will
common (and safest) method of dealing with a class
ignite if an ignition source is present.
CHARLIE fire is to secure the electrical power, and
treat it as a class ALPHA (burning insulation) fire.
WARNING
WARNING
Fuels and other liquids stored aboard ship
are often pressurized (to pump them to other
areas of the ship), or may be stored under
Special care must be taken to avoid
pressure to minimize the release of vapors.
contact with energized electrical equipment.
Leaks in these pressurized fuel systems will
CO2 bottles must be grounded, and the horn of
tend to spray outward, and they often atomize,
the portable extinguisher must not come in
increasing the possibility of coming into
contact with the energized equipment. If it is
contact with an ignition source. As an
necessary to use water fog as an extinguishing
example, the ignition source could be a heated
agent, a minimum distance of 4 feet must be
surface in an engineering compartment or an
maintained. A straight stream of water must
electrical spark from a faulty electrical
never be used on a class CHARLIE fire, due to
component.
the likelihood of electrical shock.
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