Intermediate SFFMA Objectives: 6-02.01 – 6-02.06 8Hrs Received 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 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 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 Primary way is cooling Smothering by diluting or excluding oxygen Firefighter I
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 Absorption Latent heat of vaporization Expansion capability Effective extinguishment with water generally requires steam production (Continued) Firefighter I
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 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 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 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 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 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 Streams Produce less steam conversion than fog nozzles Can be used to apply compressed-air foam Firefighter I
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 What type of fire situation would be ideal for a solid-stream nozzle? Firefighter I
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 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 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 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 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 Two types of nozzles control rate of water flow through fog nozzle Manually adjustable nozzles Automatic nozzles Firefighter I
DISCUSSION QUESTION How should adjustments to the rate of flow be made? Firefighter I
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 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 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 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 Separating Cooling Smothering Penetrating Firefighter II
Terms Associated With Foam Foam concentrate Foam proportioner Foam solution Foam (finished foam) Firefighter II
How Foam is Generated Foams used today are of mechanical type and before use must be Proportioned Aerated (Continued) Firefighter II
How Foam is Generated Elements needed to produce fire fighting foam Foam concentrate Water Air Mechanical agitation (Continued) Firefighter II
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 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 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 Increasingly used in both wildland and structural fire fighting (Continued) Firefighter II
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 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 Foam Used to suppress vapors from unignited spills of these liquids Several types of Class B foam concentrates available (Continued) Firefighter II
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 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 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 Numerous types of foam available for specific applications Properties of foams vary Firefighter II
Proportioning Mixing of water with foam concentrate to form foam solution Most concentrates can be mixed with fresh/salt water (Continued) Firefighter II
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
Proportioning Firefighter II
Proportioning Methods Induction Injection (Continued) Firefighter II
Proportioning Methods Batch-mixing Premixing Courtesy of Ansul. Firefighter II
DISCUSSION QUESTION What proportion methods does your department use? Firefighter II
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 Simplest, most common form of proportioning devices In-line foam eductors Foam nozzle eductors Firefighter II
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
DISCUSSION QUESTION What is the advantage of an apparatus-mounted proportioner? Firefighter II
Compressed-Air Foam Systems (CAFS) Newer structural engines are equipped with CAFS (Continued) Firefighter II
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 (CAFS) Unlike other systems, hoseline contains finished foam Advantages Disadvantages Firefighter II
Handline Nozzles Solid-bore nozzles Fog nozzles Air-aspirating foam nozzles Firefighter II
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 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 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 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 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 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 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 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 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 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 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
DISCUSSION QUESTION What are some examples of when each of these techniques should be used? Firefighter II
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 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 Most Class A, Class B foam concentrates are mildly corrosive Follow proper flushing procedures to prevent damage Firefighter II
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 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 Environment Chemical properties of Class B foams and environmental impact vary on type and manufacturer Protein-based foams safer for environment (Continued) Firefighter II