class of fire, the primary agent and best method for
extinguishing the fire can be determined as shown in
figure 12-9.
Many substances, such as liquids, gases, and solids,
are used as firefighting agents. The selection and use of
these agents varies with the class of fire, its location, and
the extent of the fire involvement. Although seawater is
the most valuable firefighting agent available based on
its endless supply, considerations should always be
taken to determine if water is the best agent to put out the
type of fire being fought.
REVIEW 7 QUESTIONS
Q1. Match the class of fire with the types of materials
involved.
12-22
Student Notes:
CLASSES OF
FIRE
TYPES OF MATERIALS
INVOLVED
METHOD(S) OF EXTINGUISHING
A
Wood and wood products,
cloth, textiles and fibrous
materials, and paper and
paper products.
Water in straight or fog pattern. If the fire is deep-seated,
aqueous film forming foam (AFFF) is more effective than
seawater and can be used as a wetting agent.
B
Flammable liquids, such as
gasoline, diesel fuel (F-76),
jet fuels, hydraulic fluid, and
lube oil. Also, involves
flammable gases.
Extinguished with AFFF, Halon 1211, Halon 1301, or
potassium bicarbonate (PKP). Never extinguish flammable
gases unless there is a good chance that the flow of gas can
be secured. Securing the flow of gas is the single most
important step in controlling a gas fire.
C
Energized electrical fires.
Use nonconductive agents, such as CO2, Halon 1211, or
water spray. Most effective tactic is to de-energize and
handle the fire as a class A fire. If fire isn’t deep-seated,
clean agents that don’t a cleanup problem are preferred
(CO2 or Halon 1211).
D
Combustible metals, such as
magnesium and titanium.
Water in quantity, using fog patterns. When water is
applied to burning class D materials, explosions may occur.
Apply water from a safe distance or from behind shelter.
Figure 12-9.—Classes of fire.
MATERIALS
CLASSES OF FIRE
a.
Hydraulic fluid
A
b. Energized circuit board
B
c.
Paper
C
d. Gasoline
D
e.
Magnesium
f.
Cloth
g. Titanium
