Step 5. Discharge the dry chemical by squeezing
Step 4. Remove any dry chemical from the
internal threads of the bottle and from the threads of the
the squeeze grip on the nozzle. Hold the nozzle firmly
cap.
and direct the dry chemical at the base of the fire. Use a
wide-sweeping motion from side to side. This will
Step 5.
Replace the fill cap.
apply a dense, wide cloud of dry chemical over the area.
The steps of the procedure you should adhere to
Remember that the 27-pound extinguisher has a 21-foot
when installing a new CO2 cartridge are as follows:
range and the 18-pound extinguisher has a reach of
19 feet.
Step 1. Lift the lever cutter assembly and insert
the locking pin.
Step 6. Be certain that all of the fire in the area in
which you are working is extinguished before you move
Step 2.
Reseal the locking pin and cutter lever.
in farther. If the fire appears to be too large or if there is a
Step 3.
Remove the guard covering the CO2
possibility of being outflanked or surrounded by flames,
cartridge.
attack the fire with the assistance of two or more
Unscrew the expended CO2 cartridge.
Step 4.
personnel using extinguishers.
Step 5. Remove the cap and gasket from a new
Step 7. Do not try to economize on the dry
CO2 cartridge.
chemical. Use as much as necessary (and as many
extinguishers as necessary) to extinguish the fire
Step 6. Thread the new cartridge, which has
completely.
left-hand threads, into the fitting of the cutter assembly.
Step 8.
Always back up dry chemical with water
Replace the CO2 cartridge guard.
Step 7.
or foam.
AQUEOUS FILM-FORMING FOAM FIRE
Step 9. After a dry chemical extinguisher has
EXTINGUISHER
been used, invert the cylinder, squeeze the discharge
Portable aqueous film-forming foam (AFFF) fire
lever of the nozzle, and tap the nozzle on the deck. This
extinguishers are used to provide a vapor seal over a
will release any pressure left in the cylinder and
small fuel spill, extinguish small class BRAVO fires
cartridge and any dry chemical left in the hose and
(such as deep fat fryers), and for standing fire watch
nozzle. By inverting the cylinder, you prevent further
during hotwork.
discharge of dry chemical and conserve the powder.
The portable AFFF fire extinguisher (fig. 5-2) is a
Make sure that dry chemical does not remain in the hose
stainless steel cylinder containing 2 1/2 gallons of
and nozzle; it will cake up and clog them.
p r e m i x e d A F F F c o n c e n t r a t e a n d w a t e r. I t i s
The steps of the procedure you should adhere to
pressurized with air to 100 psi at 70 and weighs
when recharging a dry chemical extinguisher are as
approximately 28 pounds when fully charged. The
follows:
mixture will expand about 6.5 to 1 and will produce
about 16 gallons of foam. The AFFF extinguisher has a
Step 1. Invert the extinguisher and tap the side of
55-65 second continuous discharge time and an initial
the cylinder with the nozzle to knock down any loose
range of 15 feet, which decreases during discharge.
dry chemical. Then bleed off the pressure.
Step 2.
Remove the fill cap.
WARNING
D o N OT l e a n o v e r t h e t o p o f t h e
extinguisher when you remove the fill cap. If
dry chemical splashes on you, it could cause
severe injury to your skin and eyes.
Step 3. Fill the cylinder with dry chemical only to
the bend in the tube. The extra space allows the powder to
DCf0502
be aerated when the cylinder is pressurized. This ensures
Figure 5-2. Portable aqueous film-forming foam fire
that the powder will not be caked when it is applied.
extinguisher.
5-2
