1. Fire Streams
Module II & III

2. Fire Hydraulics
Deal with properties of energy, pressure, and water flow as related to fire suppression.

3. Flow Volume of water that is being moved
Measured in gallons per minute (gpm)
Metric measured in liters per minute (lpm)

4. Pressure Amount of energy in a body or stream of water
Measured in pounds per square inch (psi)
Metric measured in kilopascals (kPa)
Required to push water through a hose or to a higher level
Pumps usually provide the pressure.

5. Friction Loss Loss of pressure as water moves through a pipe or hose
Loss represents the energy required to push the water.
Greater flow in same hose, greater friction loss
Smaller hose with same flow, greater friction loss
All else equal, loss proportional to distance

7. Elevation Pressure Elevation affects water pressure.
Elevated water tanks supply pressure to pipes due to elevation.
Difference between nozzle elevation and engine elevation affects pressure.
Hoses laid downhill have greater pressure.
Hoses laid up stairs will have less pressure.

9. Water Hammer
Surge in pressure caused by sudden stop in the flow of water
Shock wave is transmitted back through the hose.
Can damage hose, couplings, and plumbing
To prevent, open and close valves slowly.

11. Foam Used to fight several types of fires
Used to prevent ignition of materials
Used to neutralize hazardous materials
Produced by mixing foam concentrate with water and air

12. Foam Classifications (1 of 2)
Class A foam
Used to fight fires involving ordinary combustible materials
Increases effectiveness of water by reducing the surface tension of water
Can be added to water streams and applied with several types of nozzles

14. Foam Classifications (2 of 2)
Class B foam
Used for class B fires
Specific foam varies by type of flammable liquid
Separates fuel from the fire
Foam blanket must not be disturbed
Can be applied to flammable liquid spills to prevent fire

16. Class A Foam Concentrates
From 0.1% to 1% solution
“Wet” foam has good penetration properties.
“Stiff” foam is more effective when applied for protecting buildings.

17. Class B Foam Concentrates (1 of 3)
Used as either 3% or 6% solution
Types of foams should not be mixed.
Brands of the same foams should not be mixed.
Incompatible mixtures may congeal and plug foam systems.
Older foams have environmental hazards.

18. Class B Foam Concentrates (2 of 3)
Protein foams
Made from animal byproducts
Effective on hydrocarbon fires
Fluoroprotein foams
Made with same base materials as protein foam
Includes a flurochemical surfactant
Produce fast-spreading membrane
Provide a greater seal against edges of objects

19. Class B Foam Concentrates (3 of 3)
Aqueous film-forming foam (AFFF)
Synthetic base
Particularly suited for gasoline
Seals across surface quickly
Excellent vapor suppression ability
Alcohol-resistant foam
Properties similar to AFFF
Won’t dissolve in alcohols and other polar solvents

23. Ways Fire Fighting Foam Extinguishes/Prevents Fire
Separating
Cooling
Smothering
Penetrating

24. Terms Associated With Foam
Foam concentrate
Foam proportioner
Foam solution
Foam (finished foam)

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

26. How Foam is Generated Elements needed to produce fire fighting foam
Foam concentrate
Water
Air
Mechanical agitation
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27. How Foam is Generated
All elements must be present and blended in correct ratios
Aeration produces foam bubbles to form effective foam blanket

28. Foam Expansion The increase in volume of foam when aerated
Method of aerating results in varying degrees of expansion
Types of foam

29. 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

30. Class A Foam
Increasingly used in both wildland and structural fire fighting
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31. 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

32. Class B Foam
Used to prevent ignition of or extinguish fires involving flammable and combustible liquids
Courtesy of Williams Fire & Hazard Control, Inc.
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33. Class B Foam
Used to suppress vapors from unignited spills of these liquids
Several types of Class B foam concentrates available
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34. 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)

35. 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)

36. 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

37. Specific Application Foams
Numerous types of foam available for specific applications
Properties of foams vary

38. Proportioning
Mixing of water with foam concentrate to form foam solution
Most concentrates can be mixed with fresh/salt water
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39. 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
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40. Proportioning

41. Proportioning Methods
Induction
Injection
(Continued)

42. Proportioning Methods
Batch-mixing
Premixing
Courtesy of Ansul.

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

44. Portable Foam Proportioners
Simplest, most common form of proportioning devices
In-line foam eductors
Foam nozzle eductors

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

46. Compressed-Air Foam Systems (CAFS)
Newer structural engines are equipped with CAFS
(Continued)

47. Compressed-Air Foam Systems (CAFS)
Standard centrifugal pump supplies water, direct-injection foam-proportioning system mixes foam solution with water on discharge side of pump, onboard air compressor adds air to mix before discharging from engine
(Continued)

48. Compressed-Air Foam Systems (CAFS)
Unlike other systems, hoseline contains finished foam
Advantages
Disadvantages

49. Handline Nozzles Solid-bore nozzles Fog nozzles
Air-aspirating foam nozzles

50. Medium- and High-Expansion Foam Generating Devices
Produce foam that is semistable with high air content
Medium-expansion foam
High-expansion foam
Water-aspirating type nozzle
Mechanical blower generator

51. Reasons for Poor-Quality Foam/ Failure to Generate Foam
Eductor, nozzle flow ratings do not match so foam concentrate cannot induct into fire stream
Air leaks at fittings cause loss of suction
(Continued)

52. Reasons for Poor-Quality Foam/ Failure to Generate Foam
Improper cleaning of proportioning equipment causes clogged foam passages
Nozzle not fully open, restricting water flow
(Continued)

53. Reasons for Poor-Quality Foam/ Failure to Generate Foam
Hose lay on discharge side of eductor is too long
Hose is kinked and stops flow
Nozzle is too far above eductor
(Continued)

54. Reasons for Poor-Quality Foam/ Failure to Generate Foam
Mixing different types of foam concentrate in same tank results in mixture too viscous to pass through eductor

55. Roll-On Foam Application Method
Directs foam stream on ground near front edge of burning liquid spill
Foam rolls across surface of fuel
(Continued)

56. Roll-On Foam Application Method
Firefighters continue to apply foam until spreads across entire surface of fuel and fire extinguished
Used only on pool of liquid fuel on open ground

57. Bank-Down Foam Application Method
May be employed when elevated object is near/ within area of burning pool of liquid or unignited liquid spill
Object may be wall, tank shell, similar vertical structure
(Continued)

58. Bank-Down Foam Application Method
Foam stream directed onto object, allowing foam to run down onto surface of fuel
Used primarily in dike fires, fires involving spills around damaged/ overturned transport vehicles

59. Rain-Down Foam Application Method
Used when other two methods not feasible because of size of spill area or lack of object from which to bank foam
(Continued)

60. Rain-Down Foam Application Method
Primary manual application technique on aboveground storage tank fires
Directs stream into air above fire/spill, allows foam to float gently down onto surface of fuel

61. Foam Hazards to Humans
Foam concentrates pose minimal health risks to humans
May be mildly irritating to skin, eyes
(Continued)

62. Foam Hazards to Humans Affected areas should be flushed with water
Some concentrates, vapors may be harmful if ingested/inhaled
Consult MSDS for specific information

63. Foam Hazards to Equipment
Most Class A, Class B foam concentrates are mildly corrosive
Follow proper flushing procedures to prevent damage

64. Foam Hazards to Environment
Primary impact is effect of finished foam after application to fire/liquid spill
Biodegradability of foam determined by rate at which environmental bacteria cause decomposition
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65. Foam Hazards to Environment
Environmental impact of foam concentrates varies
In the U.S., Class A foams should be approved by USDA Forest Service
(Continued)

66. Foam Hazards to Environment
Chemical properties of Class B foams and environmental impact vary on type and manufacturer
Protein-based foams safer for environment
(Continued)

67. Summary
Firefighters must know the differences between the classes of foam, how to generate foam, and how to apply foam most effectively