PRINCIPLES OF NAVAL ENGINEERING 



CONTROL OF FIRES 



Fire is a constant potential hazard aboard 

 ship. All possible measures must be taken to 

 prevent its occurrence or to bring about its 

 rapid control and extinguishment. In many cases, 

 fire occurs in conjunction with other damage, 

 as a result of enemy action, weather, or acci- 

 dent. Unless fire is rapidly and effectively ex- 

 tinguished, it may cause more damage than the 

 initial casualty and it may, in fact, cause the 

 loss of a ship even after other damage has been 

 repaired or minimized. 



Fires are classified according to the nature 

 of the combustible material. Class A fires are 

 those which involve ordinary combustible mate- 

 rial such as wood, paper, mattresses, canvas, 

 etc. Class B fires are those which involve the 

 burning of oils, greases, gasoline, and similar 

 materials. Class C fires are those which occur 

 in electrical equipment. Class D fires are those 

 which involve certain metals such as magne- 

 sium, potassium, powdered aluminum zinc, 

 sodium, titanium, zirconium and others. 



Class A fires are extinguished by the use 

 of water. Class B fires are extinguished chiefly 

 by smothering with foam, fog, steam, or purple 

 K powder dry chemical agent (as appropriate 

 for the particular fire). Class C fires are 

 preferably extinguished by the use of carbon 

 dioxide. Because of the danger of electric shock, 

 a solid stream of water must never be used 

 to extinguish a class C fire. Class D fires are 

 presently extinguished by using large amounts 

 of water. Personnel safety is of prime concern 

 when fighting this class fire; toxic gasses, 

 possible hydrogen explosions, splattering of 

 molten metal, and intense heat are prime char- 

 acteristics of this type of fire. Presently, 

 intensive research is being conducted on better 

 methods of attack and more suitable extinguish- 

 ing agents. 



The organization of a firefighting party de- 

 pends on the number of men available. Figure 

 4-1 shows the basic organization of a small 

 firefighting party, and figure 4-2 shows the 

 basic organization of a large firefighting party. 

 At times it is necessary for one person to per- 

 form more than one of the indicated duties, and 

 this fact is taken into consideration in organiz- 

 ing firefighting parties. 



One man in the firefighting party must be 

 designated as the groupor scene leader (investi- 

 gator). His first duty is to get to the fire quickly; 

 he investigates the situation, determines the 



8.80 

 Figure 4-1.— Organization of small firefighting 

 party. 



nature of the fire, decides what type of equip- 

 ment should be used, and informs damage con- 

 trol central. Later developments may require 

 the use of different or additional equipment, 

 but the scene leader must decide what to use 

 first. 



The number of hosemen assigned to a fire- 

 fighting party varies in accordance with the 

 number of men available and the size of the 

 firehose. At least three men are required for 

 a 1 1/2-inch hose, and four or five men are 

 required for a 2 1/2-inch hose. The hosemen 

 lead out the hose, remove kinks and sharp bends, 

 and stand by the nozzles. Nozzlemen should 

 wear oxygen breathing apparatus (OBA) while 

 fighting fires. 



The plugman stands by to operate the fire- 

 plug valve, when so ordered. He rigs and stands 

 by jumper lines, assists on the hose lines, and 

 clears the fireplug strainer when necessary. 



The access men open doors, hatches, 

 scuttles, and other openings and clear routes 

 as necessary to gain access to the fire. These 

 men carry equipment to open jammed fittings 

 and locked doors. Once they have gained access 

 to the fire, they make a detailed investigation 

 of the fire area. 



The foam supply man sets up the foam equip- 

 ment for operation and operates it as required. 

 He obtains spare foam cans from racks and 

 prepares them for use. 



The electrical kit man (or electrician) de- 

 energizes all electrical equipment in the fire 

 area, both to protect personnel and to prevent 

 explosions or flashbacks. When necessary, he 

 rigs power cables for portable tools, lights, and 

 blowers. 



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