b. Fire Extinguishers, Descriptions, Class Uses, and Directions. With the exception of water,
the three most common types of fire extinguishers are-
(1) CO2 extinguishers (Figure 1-22, page 1-31) may be used on Class B and C fires. To
operate a C02 extinguisher, pull the seal locking pin and open the operating valve. Direct the C02
toward the base of the fire with a sweeping motion.
(2) Dry chemical extinguishers may be used on Class B and C fires. These units contain a
dry powder, usually sodium bicarbonate, and an activating agent of CO2 or nitrogen gas. Do not use
these units on trash fires. To operate the extinguisher, remove the locking pin, open the cartridge
discharge valve, and squeeze the nozzle handle.
(3) Foam extinguishers (Figure 1-23, page 1-31) may be used on Class A and B fires. For a
fire involving liquids, invert the extinguisher and direct the hose so that the foam is played over the
surface of the fire. In a solid-material fire, direct the stream of foam to fall lightly on or flow over the
burning surface of the material.
c. Fire-Prevention Safety Rules. Observe the following safety rules in connection with fire
Prevent the obstruction of approaches (driveways, doors, and aisles) to fire-fighting
apparatus or equipment.
Avoid using flammable liquids to start fires in a salamander or a rubbish pile.
Use a low-hazard solvent, preferably nonflammable, instead of gasoline as a cleaning
Avoid the use of a gasoline furnace or a blowtorch where flammable vapors are present.
Train all personnel in the use and the proper selection of a fire extinguisher that is
appropriate to the different classes of fires.
Notify the fire department immediately whenever a fire extinguisher has been used so
that it can be recharged or replaced.