• Home
  • Download PDF
  • Order CD-ROM
  • Order in Print
METHODS OF HEAT TRANSFER - 14325_350
REVIEW 7 QUESTIONS - 14325_352

Basic Military Requirements (BMR) Revised Edition
Page Navigation
  333    334    335    336    337  338  339    340    341    342    343  
than solid streams, reducing run off and the effect on ship stability. Convection Convection  is  the  transfer  of  heat  through  the motion  of  circulating  gases  or  liquids.  Heat  is transferred by convection through the motion of smoke, hot air, and heated gases produced by a fire. When heat is confined (as within a ship), convected heat  moves  in  predictable  patterns.  The  fire  produces lighter than air gases that rise toward high parts of the ship. Heated air, which is lighter than cooler air, also rises. As these heated combustion products rise, cool air takes their place; the cool air is heated, in turn, and then rises to the highest point it can reach. Hot smoke originating at a fire on a low deck will travel horizontally along passageways, and then upward by  way  of  ladder  and  hatch  openings,  heating flammable materials in its path. To prevent fire spread, release the heat, smoke, and gases to the atmosphere. However,  the  structural  design  of  a  ship  makes  it difficult  to  rapidly  cut  openings  through  decks, bulkheads,  or  the  ship’s  hull  for  ventilation.  It  is imperative  that  the  fire  be  confined  to  the  smallest possible  area.  Doors  and  hatchways  should  be  kept closed when they are not in use. If a fire is discovered, attempts should be made to close off all openings to the fire area until firefighting personnel and equipment can be brought into position to fight the fire. Radiation Heat radiation is the transfer of heat from a source across  an  intervening  space;  no  material  substance  is involved. The heat travels outward from the fire in the same manner as light; that is, in straight lines. When it contacts a body, it’s absorbed, reflected, or transmitted. Absorbed  heat  increases  the  temperature  of  the absorbing  body.  For  example,  radiant  heat  that  is absorbed by an overhead will increase the temperature of that overhead, perhaps enough to ignite its paint. Heat radiates in all directions unless it’s blocked. Radiant  heat  extends  fire  by  heating  combustible substances in its path, causing them to produce vapors, then igniting the vapor. Within a ship, radiant heat raises the temperature of combustible materials near the fire and, depending on the ship’s design, at quite some distance from the fire. Ship fires can spread as a result of radiating bulkheads and decks. Intense radiated heat can make an approach to the fire extremely difficult. For this reason, protective clothing should be worn by firefighters. REVIEW 6 QUESTIONS Q1.   Fire prevention is the responsibility of— Q2.   List the three components that make up a fire. a. b. c. Q3.   What  process  is  involved  in  most  cases  of spontaneous combustion? Q4.   List the three methods of heat transfer. a. b. c. CLASSES OF FIRE Learning Objective: When you finish this chapter, you will be able to— Recognize  the  four  classifications  of  fire  and identify the means used to extinguish them. Fires  are  divided  into  four  classifications,  each indicating the type of material burning. By knowing the 12-21 Student Notes:







Western Governors University

Privacy Statement
Press Release
Contact

© Copyright Integrated Publishing, Inc.. All Rights Reserved. Design by Strategico.