Quantcast Section VI. EXTINGUISHING AGENTS - TM-55-1915-200-SDC0056

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TM 55-1915-200-SDC
deep fat fryer fire. If not, AFFF or PKP extinguishers should be used, applying the AFFF continuously or the chemical in
short bursts of 3 seconds to extinguish flames. Repeat if oil reignites. The range exhaust hood damper should be closed
immediately. As soon as a fire hose with a low-velocity fog applicator is charged, apply water fog simultaneously with a
3-second PKP extinguisher discharge if the fire is still burning. If the oil reignites, repeat this procedure. Low-velocity
fog should be maintained available for the reflash watch.
f. Gasoline. Fires involving gasoline fuel can be extinguished only by smothering. CO2 provides only temporary
smothering and, the flammable vapors which continue to evolve from these fuels at ordinary temperatures can easily be
reignited causing the fire to begin all over again. Dry chemical agents provide a more permanent smothering effect and
should be utilized to avoid reignition. Since water does not mix with these fuels, nor does it stop evolution of flammable
vapors, water alone usually causes flammable fuel fires to spread dangerously.
g. Paper products. Paper products constitute one of the larger fire loads, but if good housekeeping is observed,
there is a low potential for a large fire.
Section VI. EXTINGUISHING AGENTS
6-14. TYPES OF AGENTS. The extinguishing agents dispensed from hand-held equipment and which are used on
ships are water, carbon dioxide (CO2), dry potassium bicarbonate chemical (PKP), and Aqueous Film Forming Foam
(AFFF).
a. Water.  Water is, and has long been, the most commonly used extinguishing agent.  Water lowers the
temperature of a burning substance below its ignition point. Water brought to bear on a fire can be in the form of high-
velocity fog, low-velocity fog or solid stream using the all-purpose nozzle. Extensive fire tests have shown that the all-
purpose nozzle with the low-velocity fog applicator is the best nozzle for ship use. Using water in the form of water fog
greatly increases the surface area and consequently the rate of heat exchange between the burning material and the
water. This heat exchange produces steam, which has a smothering effect on fire.
(1) High-velocity fog. High-velocity fog allows the fire fighter to attack the fire from a greater distance and will
cause cool air to be drawn toward the fire past the fire fighter. High-velocity fog shields the fire fighter from heat, thus
protecting from fire exposure. However, the high-velocity fog tip will also introduce more water, which is not desired in
most cases. See FIGURE 6-2. The all-purpose nozzle was designed to operate at 60 to 100 psi and, when used at the
minimum pressure, the high-velocity tip does not perform as well as the low-velocity fog based on a study conducted by
the Navy. The Navy reports a 27-square-foot pan fire could not always be extinguished using high-velocity fog but could
be extinguished consistently using low-velocity fog. See FIGURE 6-3.
6-6


 


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