Page 141 - NAVAL SCIENCE 3 TEXTBOOK

146 NAVAL SKILLS

Oxygen ClI1 be removed in h\'o ways. In a closed space, carbon rules for preventing fires Me generally the same anywhere, but
dioxide (CO) can be pumped in to displace the ox,'gen and starve special precautions must be taken in the Navy and aboard ships
the fire. Another method is to smother the fire with a blanket of because of the concentration of flammable fuels and explosives.
chemic.ll powders, toam, or sand. The first rule is to keep things squared away-clean, in good
Removing the heat side of the triangle, or cooling the fire, is order, and in their proper places. rIammable materials must be
the method most often employed, usually b)1 the use of lots of kept awa), from potential fire starters sllch as torches, cig<lretles,
water, both solid stream and fog (spray), to cool the burning sur- and sparking equipment.
lace rapidl),. Hrefighting equipment must be welll11aintained.lf a fire starts,
the right gear must be immediately available and operating prop-
erly to prevent the fire from spreading.
Classes of Fires
One of the more common causes of Class A fires is lighted cig-
There are four classes of I1res, depending on the type of fuel or arettes or matches thrown into trash cans. Smoking in bunks is
material burning and the methods required to extinguish theill. strictly forbidden by regulations, but the regulations have been bro-
Class A (Alpha) fires involve solid combustible materials such ken with serious consequences. Through spontaneous combustion,
as wood, cloth, or paper. They often leave ashes. Explosives are also piled up oily rags and papers also comlllonly cause stich fires.
in this categor)'. \Vater is the usual means of putting out Class A Class 13 fires are very difficult to predict, especially if fumes leak
fires. Carbon dioxide (CO) may be used on small fires, but not on in voids and tanks aboard ship. Sparking from welding torches,
explosives. The flames of a large fire arc usually cooled down with light switches, and even flashlights can be sufficient to calise an
fog. Then a solid stream of water is used to break up the material explosion and fire with gasoline fumes. Grease fires in galleys are
for further cooling. not uncommon if hot oil or grease spills onto burners. The smok-
elms B (Bml'o) fires involve flammable liquids such as oil, gas- ing lamp (term for permission to smoke in authorized spaces) is
oline, other fuels, cleaning agents, and paints. COl is good for put- out whenever handling fuels or explosives aboard a ship.
ting out small Class B I1res. For larger fires, light water (a mixture Paint and oils should be kept away ti'olll electric wires. Fl"il}'ed
of water and chemicals) or water fog or spray should be used. A or worn wires and insulation must be repaired or replaced imme-
solid stream of water should never be used on Class B fires; it will diatel}'. Dust alld dirt should 110t be aUo\\'cd to accumulate around
only scatter the fuel and spread the naIlleS. electrical equipment. Unauthorized c1ectric.ll i.lppliallces and over-
Clms C (Charlie) fires are those burning in electrical or elec- loaded circuits, extension cords, and plugs are an open invitation
tronic equipment stich as radios, radars, generators, and electric to overheating and fires.
control panels. The main extinguishing agents are COl and dry
chemical extinguishers. Liquids should not be used bec.ll1se they
Firefighting Equipment
will damage the equipment and may be a shock hazard. If at all
possible, electrical gear should be deenergizcd before any I1re- The fire main s},stem aboard ship is designed to deliver se,lwa-
fighting is undertaken, to eliminate the potential shock hazard. ter to fireplugs and sprinkler systems, just like i.l cit}"s fire main
Electricity can trawl along wet decks and electrocute firefighters. delivers water under pressure to the fire hydrants. 1\\'0 connected
Clnss D (De/ta) fires involve combustible metals such as mag- 50-foot lengths of fire hose---one end attached to the I1re main,
nesium, titanium, sodium, and in some cases, aluminum. These the other fitted with a nozzle-arc placed on racks at each fire sta-
elements arc used in certain parts of ships, aircraft, missiles, some tioll throughout a ship. AdditiOlli.lllengths of hose are rolled and
weapons, and computers and other electronic gear. A magnesium stowed in repair lockers.
aircraft parachute flare, for instance, can burn ilt a temperature Sprinkler systems are installed ill magazines, gun tUITets,
greater thaI14,000° Fahrenheit, with a brilli<l11cy 01'2 trillion candle- aml1lunition-handling rooms, spaces where flammable materi-
powcr. Dry powder e)\1inguishillg agents containing sodium chlo- als arc stored, and hangar bays aboard ships that operate aircmft.
ridc granules or copper powder arc lIsed on this type of fire. "\'<lter Some systems are automatically triggered when the temperature
can excite these fires and make them worse. firefighters dealing with in the protected compartment reaches a certilin temperature. but
Class 0 fires should wem welders' goggles with dark lenses to protect most are operated manually by control valves.
their eyes from the ollen-intense glare of this type fire. Light water used to fight Class 13 fires acts as a blanket that
floats 0 11 top of the burning liquid and smothers the fire. It should
not be llsed on Class C fires because of the potential shock haz<lrds
Fire Prevention
involved.
A fire is certain to GlllSe some damage. The most firefighters C1I1 Two types of portable extillgllishers are cOlllmon: CO and
2
do is to minimize the damage and keep the fire from spreading. purple-K powder (PKP). Both are effective in nghting Class 1l and
A main objective, therefore. is to prevent fires from starting. The Class C fires. The COL extillgllisher is used mainly for putting out