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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

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fire streams

Fire Streams

Intermediate

SFFMA Objectives: 6-02.01 – 6-02.06

8Hrs Received

methods to reduce heat and provide protection
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

methods to reduce heat and provide protection1
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

how water extinguishes fire
How Water Extinguishes Fire
  • Primary way is cooling
  • Smothering by diluting or excluding oxygen

Firefighter I

heat absorption
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

heat absorption1
Heat Absorption
  • Latent heat of vaporization
  • Expansion capability
  • Effective extinguishment with water generally requires steam production

(Continued)

Firefighter I

heat absorption2
Heat Absorption
  • Water absorbs more heat when converted to steam than when heated to boiling point

Firefighter I

characteristics of water valuable for fire extinguishment
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

solid stream
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

solid stream1
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

advantages of solid streams
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

advantages of solid streams1
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

advantages of solid streams2
Advantages of Solid Streams
  • Produce less steam conversion than fog nozzles
  • Can be used to apply compressed-air foam

Firefighter I

disadvantages of solid streams
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

discussion question
DISCUSSION QUESTION

What type of fire situation would be ideal for a solid-stream nozzle?

Firefighter I

fog stream
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

fog stream1
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

fog stream2
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

fog stream3
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

fog stream4
Fog Stream
  • Shorter reach makes fog streams less useful for outside, defensive fire fighting operations
  • Well suited for fighting interior fires

Firefighter I

fog stream waterflow adjustment
Fog Stream: Waterflow Adjustment
  • Two types of nozzles control rate of water flow through fog nozzle
  • Manually adjustable nozzles
  • Automatic nozzles

Firefighter I

discussion question1
DISCUSSION QUESTION

How should adjustments to the rate of flow be made?

Firefighter I

fog stream nozzle pressure
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

fog stream nozzle pressure1
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

advantages of fog streams
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

disadvantages of fog streams
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

ways fire fighting foam extinguishes prevents fire
Ways Fire Fighting Foam Extinguishes/Prevents Fire
  • Separating
  • Cooling
  • Smothering
  • Penetrating

Firefighter II

terms associated with foam
Terms Associated With Foam
  • Foam concentrate
  • Foam proportioner
  • Foam solution
  • Foam (finished foam)

Firefighter II

how foam is generated
How Foam is Generated
  • Foams used today are of mechanical type and before use must be
    • Proportioned
    • Aerated

(Continued)

Firefighter II

how foam is generated1
How Foam is Generated
  • Elements needed to produce fire fighting foam

(Continued)

Firefighter II

how foam is generated2
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

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

Firefighter II

foam concentrates general considerations
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

class a foam
Class A Foam
  • Increasingly used in both wildland and structural fire fighting

(Continued)

Firefighter II

class a foam1
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

class b foam
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

class b foam1
Class B Foam

Used to suppress vapors from unignited spills of these liquids

Several types of Class B foam concentrates available

(Continued)

Firefighter II

class b foam2
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

class b foam3
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

class b foam4
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

specific application foams
Specific Application Foams
  • Numerous types of foam available for specific applications
  • Properties of foams vary

Firefighter II

proportioning
Proportioning
  • Mixing of water with foam concentrate to form foam solution
  • Most concentrates can be mixed with fresh/salt water

(Continued)

Firefighter II

proportioning1
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

proportioning2
Proportioning

Firefighter II

proportioning methods
Proportioning Methods
  • Induction
  • Injection

(Continued)

Firefighter II

proportioning methods1
Proportioning Methods
  • Batch-mixing
  • Premixing

Courtesy of Ansul.

Firefighter II

slide47

DISCUSSION QUESTION

What proportion methods does your department use?

Firefighter II

foam proportioners general considerations
Foam Proportioners — General Considerations
  • May be portable or apparatus-mounted
  • Operate by one of two basic principles

Courtesy of Conoco/Phillips.

Firefighter II

portable foam proportioners
Portable Foam Proportioners
  • Simplest, most common form of proportioning devices
  • In-line foam eductors
  • Foam nozzle eductors

Firefighter II

apparatus mounted proportioners
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

slide51

DISCUSSION QUESTION

What is the advantage of an apparatus-mounted proportioner?

Firefighter II

compressed air foam systems cafs
Compressed-Air Foam Systems (CAFS)
  • Newer structural engines are equipped with CAFS

(Continued)

Firefighter II

compressed air foam systems cafs1
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)

Firefighter II

compressed air foam systems cafs2
Compressed-Air Foam Systems (CAFS)
  • Unlike other systems, hoseline contains finished foam
  • Advantages
  • Disadvantages

Firefighter II

handline nozzles
Handline Nozzles
  • Solid-bore nozzles
  • Fog nozzles
  • Air-aspirating foam nozzles

Firefighter II

medium and high expansion foam generating devices
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

Firefighter II

reasons for poor quality foam failure to generate foam
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)

Firefighter II

reasons for poor quality foam failure to generate foam1
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)

Firefighter II

reasons for poor quality foam failure to generate foam2
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)

Firefighter II

reasons for poor quality foam failure to generate foam3
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

Firefighter II

roll on foam application method
Roll-On Foam Application Method
  • Directs foam stream on ground near front edge of burning liquid spill
  • Foam rolls across surface of fuel

(Continued)

Firefighter II

roll on foam application method1
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

Firefighter II

bank down foam application method
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)

Firefighter II

bank down foam application method1
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

Firefighter II

rain down foam application method
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)

Firefighter II

rain down foam application method1
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

Firefighter II

slide67

DISCUSSION QUESTION

What are some examples of when each of these techniques should be used?

Firefighter II

foam hazards to humans
Foam Hazards to Humans
  • Foam concentrates pose minimal health risks to humans
  • May be mildly irritating to skin, eyes

(Continued)

Firefighter II

foam hazards to humans1
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

Firefighter II

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

Firefighter II

foam hazards to environment
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

(Continued)

Firefighter II

foam hazards to environment1
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)

Firefighter II

foam hazards to environment2
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)

Firefighter II