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LESSON 13 Water Fire Streams

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LESSON 13 Water Fire Streams

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    2. INSTRUCTOR INTRO

    4. Water Fire Streams Used to reduce temperatures Permit closer proximity with handlines through the following methods Direct application Reduction of high temperatures Dispersion of hot smoke and fire gases Production of a water curtain to protect firefighters and property from heat

    5. Three Physical States of Water Solid(ice) Liquid(water) Vapor/steam (gas)

    7. Extinguishing Properties of Water Water extinguishes by: Cooling Smothering Smothering is accomplished by absorbing large quantities of heat and diluting oxygen Water broken into small particles absorb more heat because of greater surface area

    8. Examples of greater surface area Chipped ice vs. single ice cube Fog stream vs. solid stream steam vs. liquid

    9. Water is unique It expands upon both freezing and vaporizing Water in water mains and sprinklers may damage the pipes upon freezing Water expands 1700:1 during vaporization allowing it to absorb more heat

    11. Why must adequate ventilation be provided ahead of the hoseline when using fog stream? High possibility of steam or even fire rolling back over and around the hose team

    12. Waters Value to Fire Fighting Readily available Inexpensive Great heat-absorbing capacity > surface area=> heat absorption Steam conversion requires large amount of heat

    14. Friction Loss Critical velocity can be detected when the entire stream is being agitated by resistance When critical velocity has been reached parallel or siamese hoselines should be used to increase flow & reduce friction

    15. Causes of Friction Loss Rough hose lining Damaged couplings Sharp bends/kinks in hose Adapters Partially closed valves/ nozzles Wrong size gasket Excessive hose length Excess flow for hose size

    16. Other factors that may lead to loss of water pressure Broken hoselines Mechanical problem due to poor water supply Error in hydraulics calculation Obstructions Elevations of nozzle above pump

    17. Elevation Nozzle above ? fire pump = pressure loss? Nozzle below ? fire pump = pressure gain ?

    19. Guidelines For Reducing Pressure Loss Check for rough linings in fire hose Replace damaged hose couplings Eliminate sharp bends Use adapters only when necessary

    20. Guidelines For Reducing Pressure Loss Keep nozzles and valves fully open Use proper size gasket Use larger hose Reduce the amount of flow

    21. Water Hammer Caused by suddenly stopping water flow Often heard as a distinct clank Causes a change in direction of energy

    23. Water Hammer can cause damage to: Pumps Hoselines Water mains Couplings Nozzles Hydrants Firefighters

    24. Water Hammer Can Be Prevented By Opening and Closing Nozzle controls Hydrants Valves Hose clamps

    25. Four Essential Things Needed To Produce An Effective Fire Stream Water Pressure device Hose Nozzle

    27. Fire Streams Are Categorized By: Size low-volume handline master stream Type solid fog broken streams Rate of discharge - GPM

    29. Volume of water discharged is determined by: Nozzle design Pressure at the nozzle

    30. Affect of Fire stream volume and type on extinguishment Sufficient volume to absorb more heat than what is being created Stream type must have sufficient volume to penetrate the heated area

    32. Solid Stream Nozzles Advantages Maintain better visibility Greater reach Operate at reduced pressure Greater penetration Less likely to disturb normal thermal balance

    33. Solid Stream Nozzles Disadvantages Do not allow for different stream pattern selections Cannot be used for foam application Provide less heat absorption

    34. Fog Stream Nozzles Advantages Pattern may be adjusted Can control the amount of water Aid ventilation Dissipate heat

    35. Fog Stream Nozzles Disadvantages Don’t have the reach of solid streams Don’t have the penetration of solid streams More susceptible to wind currents May contribute to fire spread May create heat inversion May cause steam burns when improperly used

    36. Difference between solid stream and straight stream Produced from a fixed orifice smoothbore nozzle Straight stream is produced from an adjustable nozzle fog nozzle

    37. Solid streams are used when: A powerful, long-ranging, high-volume stream is desired exterior attack May be used also for interior attack

    38. Breakover point Solid stream begins to lose its forward velocity

    39. Physical Characteristics of a “good” solid stream Does not lose its continuity until it reaches breakover and falls into showers of spray Stiff enough to maintain its original shape and attain the required height even in a breeze

    44. Factors that affect the reach of a fog stream Pattern Gravity Water velocity Water droplet friction with air Wind

    47. Manually adjustable nozzles Can change the rate of discharge by rotating the selector ring May make flow adjustments before or after opening the nozzle Low-volume = 10 gpm to 250 gpm High-volume = 300 gpm to 2,500 gpm Adjustments should be made in increments to avoid nozzle reaction

    48. Automatic nozzles Automatically vary the rate of flow to maintain effective nozzle pressure Rate of flow can be changed by opening and closing the shut off valve Allow delivery of large quantities of water at constant operating pressures Allow for reduction of flow for mobility while maintaining efficient discharge pattern

    50. Three Major Types of Broken Stream, Special Application Nozzles Piercing/ penetrating nozzle Chimney nozzle Distributor(cellar) nozzle

    57. Ball Valve Provides effective control during fire fighting with minimum effort Partially opened valve may affect desired stream in solid stream nozzles(turbulence)

    58. Slide Valve Controls flow of water through nozzle without creating turbulence Compensates for increase or decrease in flow by moving the baffle

    59. Rotary Nozzle Found only in rotary control fog nozzles Controls the stream pattern as well as water flow

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