1 / 73

Fire Streams

Fire Streams. Intermediate SFFMA Objectives: 6-02.01 – 6-02.06 8Hrs Received. Methods to Reduce Heat and Provide Protection . Applying water or foam directly onto burning material to reduce its temperature

komala
Download Presentation

Fire Streams

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Fire Streams Intermediate SFFMA Objectives: 6-02.01 – 6-02.06 8Hrs Received

  2. Methods to Reduce Heat and Provide Protection • Applying water or foam directly onto burning material to reduce its temperature • Applying water or foam over an open fire to reduce the temperature so firefighters can advance handlines • Reducing high atmospheric temperature (Continued) Firefighter I

  3. Methods to Reduce Heat and Provide Protection • Dispersing hot smoke and fire gases from a heated area • Creating a water curtain to protect firefighters and property from heat • Creating a barrier between a fuel and a fire by covering the fuel with a foam blanket Firefighter I

  4. How Water Extinguishes Fire • Primary way is cooling • Smothering by diluting or excluding oxygen Firefighter I

  5. Heat Absorption • When heated to boiling point, water absorbs heat • Visible form of steam is called condensed steam • Components of heat absorption • Specific heat (Continued) Firefighter I

  6. Heat Absorption • Latent heat of vaporization • Expansion capability • Effective extinguishment with water generally requires steam production (Continued) Firefighter I

  7. Heat Absorption • Water absorbs more heat when converted to steam than when heated to boiling point Firefighter I

  8. Characteristics of Water Valuable for Fire Extinguishment • Readily available, relatively inexpensive • Has greater heat-absorbing capacity than most other common agents • Water changing to steam requires large amount of heat • Can be applied in variety of ways Firefighter I

  9. Solid Stream • Produced from fixed orifice, solid-bore nozzle • Has ability to reach areas others might not; reach affected by several factors • Design capabilities (Continued) Firefighter I

  10. Solid Stream • Velocity of stream a result of nozzle pressure • Nozzle pressure, size of discharge opening determine flow • Characteristics of effective fire streams • Flow rate Firefighter I

  11. Advantages of Solid Streams • May maintain better interior visibility than others • May have greater reach than others • Operate at reduced nozzle pressures per gallon (liter) than others • May be easier to maneuver (Continued) Firefighter I

  12. Advantages of Solid Streams • Have greater penetration power • Less likely to disturb normal thermal layering of heat, gases during interior structural attacks • Less prone to clogging with debris (Continued) Firefighter I

  13. Advantages of Solid Streams • Produce less steam conversion than fog nozzles • Can be used to apply compressed-air foam Firefighter I

  14. Disadvantages of Solid Streams • Do not allow for different stream pattern selections • Provide less heat absorption per gallon (liter) delivered than others • Hoselines more easily kinked at corners, obstructions Firefighter I

  15. DISCUSSION QUESTION What type of fire situation would be ideal for a solid-stream nozzle? Firefighter I

  16. Fog Stream • Fine spray composed of tiny water droplets • Design of most fog nozzles permits adjustment of tip to produce different stream patterns (Continued) Firefighter I

  17. Fog Stream • Water droplets formed to expose maximum water surface for heat absorption • Desired performance of fog stream nozzles judged by amount of heat that fog stream absorbs and rate by which the water is converted into steam/vapor (Continued) Firefighter I

  18. Fog Stream • Nozzles permit settings of straight stream, narrow-angle fog, and wide-angle fog • Nozzles should be operated at designed nozzle pressure (Continued) Firefighter I

  19. Fog Stream • Several factors affect reach of fog stream • Interaction of these factors on fog stream results in fire stream with less reach than that of straight or solid stream (Continued) Firefighter I

  20. Fog Stream • Shorter reach makes fog streams less useful for outside, defensive fire fighting operations • Well suited for fighting interior fires Firefighter I

  21. Fog Stream: Waterflow Adjustment • Two types of nozzles control rate of water flow through fog nozzle • Manually adjustable nozzles • Automatic nozzles Firefighter I

  22. DISCUSSION QUESTION How should adjustments to the rate of flow be made? Firefighter I

  23. Fog Stream: Nozzle Pressure • Combination nozzles designed to operate at different pressures • Designated operating pressure for most combination nozzles is 100 psi (700 kPa) (Continued) Firefighter I

  24. Fog Stream: Nozzle Pressure • Nozzles with other designated operating pressures available • Setbacks of nozzles with lower operating pressures Courtesy of Elkhart Brass Manufacturing Company. Firefighter I

  25. Advantages of Fog Streams • Discharge pattern can be adjusted for situation • Can aid ventilation • Reduce heat by exposing maximum water surface for heat absorption • Wide fog pattern provides protection to firefighters Firefighter I

  26. Disadvantages of Fog Streams • Do not have as much reach/penetrating power as solid streams • More affected by wind than solid streams • May disturb thermal layering • May push air into fire area, intensifying the fire Firefighter I

  27. Ways Fire Fighting Foam Extinguishes/Prevents Fire • Separating • Cooling • Smothering • Penetrating Firefighter II

  28. Terms Associated With Foam • Foam concentrate • Foam proportioner • Foam solution • Foam (finished foam) Firefighter II

  29. How Foam is Generated • Foams used today are of mechanical type and before use must be • Proportioned • Aerated (Continued) Firefighter II

  30. How Foam is Generated • Elements needed to produce fire fighting foam (Continued) Firefighter II

  31. How Foam is Generated • All elements must be present and blended in correct ratios • Aeration produces foam bubbles to form effective foam blanket Firefighter II

  32. Foam Expansion • The increase in volume of foam when aerated • Method of aerating results in varying degrees of expansion • Types of foam Firefighter II

  33. Foam Concentrates — General Considerations • Foam concentrates must match fuel to which applied • Class A foams not designed to extinguish Class B fires • Class B foams designed solely for hydrocarbon fires will not extinguish polar solvent fires Firefighter II

  34. Class A Foam • Increasingly used in both wildland and structural fire fighting (Continued) Firefighter II

  35. Class A Foam • Special formulation of hydrocarbon surfactants • Aerated Class A foam coats, insulates fuels, preventing pyrolysis and ignition • May be used with variety of nozzles Firefighter II

  36. Class B Foam • Used to prevent ignition of or extinguish fires involving flammable and combustible liquids Courtesy of Williams Fire & Hazard Control, Inc. (Continued) Firefighter II

  37. Class B Foam Used to suppress vapors from unignited spills of these liquids Several types of Class B foam concentrates available (Continued) Firefighter II

  38. Class B Foam • Manufactured from synthetic or protein base • May be proportioned into the fire stream through fixed system, apparatus-mounted system, or by portable foam proportioning equipment (Continued) Firefighter II

  39. Class B Foam • Foams such as AFFF and FFFP foam may be applied with standard fog nozzles or air-aspirating foam nozzles Courtesy of Harvey Eisner. (Continued) Firefighter II

  40. Class B Foam • Rate of application depends on several factors • Unignited spills do not require same application rates as ignited spills • To be most effective, blanket of foam 4 inches (100 mm) thick should be applied to fuel surface Firefighter II

  41. Specific Application Foams • Numerous types of foam available for specific applications • Properties of foams vary Firefighter II

  42. Proportioning • Mixing of water with foam concentrate to form foam solution • Most concentrates can be mixed with fresh/salt water (Continued) Firefighter II

  43. Proportioning • For maximum effectiveness, foam concentrates must be proportioned at designated percentage • Most fire fighting foams intended to be mixed with 94 to 99.9 percent water (Continued) Firefighter II

  44. Proportioning Firefighter II

  45. Proportioning Methods • Induction • Injection (Continued) Firefighter II

  46. Proportioning Methods • Batch-mixing • Premixing Courtesy of Ansul. Firefighter II

  47. DISCUSSION QUESTION What proportion methods does your department use? Firefighter II

  48. Foam Proportioners — General Considerations • May be portable or apparatus-mounted • Operate by one of two basic principles Courtesy of Conoco/Phillips. Firefighter II

  49. Portable Foam Proportioners • Simplest, most common form of proportioning devices • In-line foam eductors • Foam nozzle eductors Firefighter II

  50. Apparatus-Mounted Proportioners • Mounted on structural, industrial, wildland, and aircraft rescue and fire fighting apparatus, as well as on fire boats • Three types Firefighter II

More Related