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20 Cards in this Set
- Front
- Back
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Define a fire stream
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A stream of water or other extinguishing agent after it leaves a fire hose and nozzle until it reaches the desired point
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Streams are influenced by
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+Operating Pressure
+Nozzle adjustment +Nozzle design +condition of orifice +velocity, gravity, wind, friction with air |
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Physical states of water
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+solid: -32 degrees
+liquid: -32 to 212 degrees +gas: Above 212 degrees |
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Expansion capability when converted to steam
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+Cools fire by driving heat and smoke away
+Steam prudced aids in smothering and reduces oxygen +Can cause injuries to firefighters and occupants |
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Ways water extinguishes
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+Cooling
+Smothering: Obsorbs heat and dilutes oxygen. coverts liquid to a gas |
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Surface area
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+Same principle as surface area to mass ratio
+Small droplets of water VS large solid stream of water |
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Why Water
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+Available and inexpensive
+Good heat obsorption +Water to steam requires lots of heat +Greater the water surface are the faster it obsorbs heat |
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Pressure Loss/Gain
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Friction loss: Total +Friction loss: pressure lost while forcing water through pipes, fittings, hose and adapters
+Elevation: Posistion of nozzle in relation to the pumping apparatus |
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Reason for pressure loss
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+Damage Couplings
+Kinks or bends +Elevation +Hose diameter/Length |
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Water Hammer
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Closing all nozzles and valves slowly
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Fire streams classified by size
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+Low Volume streams: Discharge less than 40gpm
+Handlines: Discharge 40-350GPM fed by 1 1/2 to 3 inch +Master streams: Discharge more than 350 GPM fed by 2 1/2 to 3 inch supply lines |
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Fire Streams by characteristics
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+Pressuring device (pump)
+hose +Agent (water) +Nozzle |
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Solid Stream
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+Smooth Bore Nozzle:
Mfd Handlines; 7/8 and 1 1/8 at 50 psi Master streams, deluge sets, and water towers at 80 psi. 1 1/4 to 2inch |
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Solid advantages
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+Better visibility
+Greater Reach +Reduce nozzle pressure +Greater penatrating power +Less Likely to disturb thermal balance |
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Solid Disadvantage
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+No Pattern selection
+Less heat obsorption +Cannot be used for foam |
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Fog Stream patterns
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+Straight
+Narrow fog 15-45 degrees +Wide fog 45-80 Degreea |
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Fog streams
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+Composed of small water droplets
+Absorbs large amount of heat +Nozzle settings -Straight stream -narrow fog -wide fog |
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Factors affecting reach of fog stremas
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+Gravity
+water Velocity +Pattern selection +Water droplet friction with air +wind |
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Fog Advantages
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+High heat obsorption due to water surface exposure
+Aid in ventilation +Adjustable GPM Settings +Pattern Selection |
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Fog Disadvantages
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+Reach and Penetration
+susceptible to wind +May contribute to fire spread, create heat inversion and cause steam burns to FF's when used improperly without adequate ventilation |
