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The reaction acts against both the nozzle and the curves of the hoseline, making itdifficult to handle*One person can usually operate a smooth bore nozzle on a 1½” or smaller hoseline
Shiroma ifsta 20161¾” or larger hoseline require additional personnel to overcome the reaction of thehose.*as the fog patterns widens, the reaction decreases making the nozzle easier tohandlenozzles should be inspected after each use and at least annually.It should be alsocleaned after each use to prevent the build-up of contaminantsFIRE FIGHTING FOAM- works by forming a blanket of foam on the surface of burningfuels, both liquid and solids.FOAM extinguishes fires by [separating, cooling, smothering, penetrating]Separating- creates a barrier between the fuel and the fireCooling- lowers the temp. of the fuel and adjacent surfacesSmothering- prevents air from reaching the fuel and mixing with the vapors andprevents the release of flammable vapors. [reduces the possibility of reignition]Penetrating- lowers the surface tension of water and allows it to penetrate fires inclass A materialsOn solid fuels, class A foam blankets and cools the fuel and stops the burningprocess.After controlling the flames, the water in the foam is slowly released intothe fuel process as the foam breaks down.This action provides a cooling effect onthe fuel.Class a works by penetrating the fireOn class B liquid fuels, the class B blanket also prevents or reduces the release offlammable vapors from the surface of the fuel.Class B foam is especially effective onthe 2 basic categories of flammable liquids [hydrocarbons, polar solvents].Class Bfoam works by suppressing vapors, separating the fuel from the fire, cooling the fueland other surfaces, and smothering flaming combustion.Foam concentrate- chemical compound solution that is mixed with water and air toproduce finished foamFoam proportioner-device that introduces foam concentrate into the water streamto make the foam solutionFoam solution- mixture of foam concentrate and water before the introduction of air.Finished foam- completed product after air is introduced into the foam solutionAeration is needed to produce quality foam bubbles, and produces uniform-sizedbubbles that produce a linger lasting blanket.Foam expansion- refers to increase in volume of a foam solution when it is aerated,result of adding foam solution consisting of water and foam concentrate.Foam expansion depends on [type of foam, proportioning, quality of concentrate,method]
Shiroma ifsta 2016There are 3 classifications of foam based on their expansion ratio [low, medium,high]Low expansion- 20:1 ratio, effective for controlling most Class B fires and coolingand penetrating Class A firesMedium expansion- 20:1- 200:1, delivered through a hydraulically operated nozzlestyle delivery devices.Used to suppress vapors from hazardous materials spillswhen applied at expansion rates of 30:1-55:1.
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Presentation on theme: "Chapter 14 Lesson Goal After completing this lesson, the student shall be able to effectively apply fire fighting foam using various foam types, concentrates,"— Presentation transcript:
0 Essentials of Fire Fighting, 5th Edition
Chapter 14 —
Fire Streams Firefighter II
1 Chapter 14 Lesson Goal After completing this lesson, the student shall be able to effectively apply fire fighting foam using various foam types, concentrates, and delivery devices following the policies and procedures set forth by the authority having jurisdiction
[AHJ]. Firefighter II
2 Specific Objectives 1. Describe the suppression characteristics of fire fighting foam. 2. Define terms associated with types of
foam and the foam-making process. 3. Discuss how foam is generated. [Continued] Firefighter II
3 Specific Objectives 4. Discuss foam concentrates.
5. Describe methods by which foam may be proportioned.
6. Discuss foam proportioners. 7. Discuss foam delivery devices. [Continued] Firefighter II
4 Specific
Objectives 8. List reasons for failure to generate foam or for generating poor-quality foam. 9. Describe foam application techniques. [Continued] Firefighter II
5 Specific Objectives 10. Discuss hazards associated with foam
concentrates. 11. Place a foam line in service — In-line eductor. [Skill Sheet 14-II-1] Firefighter II
6 Ways Fire Fighting Foam Extinguishes/Prevents Fire
Separating Cooling
Smothering Penetrating Firefighter II
7 Terms Associated With Foam
Foam concentrate Foam proportioner Foam solution Foam [finished foam] Firefighter II
8 How Foam is Generated Foams used today are of mechanical type and before use must be Proportioned Aerated [Continued]
Firefighter II
9 How Foam is Generated Elements needed to produce fire fighting foam
Foam concentrate Water Air Mechanical agitation [Continued]
Firefighter II
10 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
11 Foam Expansion The increase in volume of foam when aerated
Method of aerating
results in varying degrees of expansion Types of foam Firefighter II
12 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
13 Class A Foam Increasingly used in both wildland and structural fire fighting Special formulation of hydrocarbon
surfactants [Continued] Firefighter II
14 Class A Foam Aerated
Class A foam coats, insulates fuels, preventing pyrolysis and ignition May be used with variety of nozzles Firefighter II
15
Class B Foam Used to prevent ignition of or extinguish fires involving flammable and combustible liquids Used to suppress vapors from unignited spills of these liquids Several types of Class B foam concentrates available [Continued] Firefighter II
16 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
17 Class B Foam Foams such as AFFF and FFFP foam may be applied with standard fog nozzles or air-aspirating foam
nozzles Rate of application depends on several factors [Continued] Firefighter II
18 Class B Foam 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
19 Specific Application Foams
Numerous types of foam available for specific applications Properties of
foams vary Firefighter II
20 Proportioning Mixing of water with foam concentrate
to form foam solution Most concentrates can be mixed with fresh/salt water [Continued] Firefighter II
21
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 Firefighter II
22 Proportioning Methods
Induction
Injection Batch-mixing Premixing Firefighter II
23 Foam Proportioners — General Considerations
May be portable or apparatus-mounted Operate by one of two basic principles
Firefighter II
24 Portable Foam Proportioners
Simplest, most common form of proportioning devices In-line foam eductors Foam nozzle eductors Firefighter II
25 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
26 Compressed-Air Foam Systems [CAFS]
Newer structural engines are equipped with CAFS [Continued] Firefighter II
27 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
28 Compressed-Air Foam Systems [CAFS]
Unlike other systems, hoseline contains finished foam Advantages Disadvantages Firefighter II
29 Handline Nozzles Solid-bore nozzles Fog nozzles
Air-aspirating foam nozzles Firefighter II
30 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
31 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 Improper cleaning of proportioning equipment causes clogged foam passages [Continued] Firefighter II
32 Reasons for Poor-Quality Foam/ Failure to Generate Foam
Nozzle not fully open,
restricting water flow Hose lay on discharge side of eductor is too long Hose is kinked and stops flow [Continued] Firefighter II
33 Reasons for Poor-Quality Foam/ Failure to Generate
Foam
Nozzle is too far above eductor Mixing different types of foam concentrate in same tank results in mixture too viscous to pass through eductor Firefighter II
34 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
35 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
36 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
37 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
38 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
39 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
40 Foam Hazards to Humans Foam concentrates pose minimal health risks to humans May be mildly irritating to skin, eyes
[Continued] Firefighter II
41 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
42 Foam Hazards to Equipment
Most Class A, Class B foam concentrates are mildly corrosive Follow proper flushing procedures to prevent damage Firefighter II
43 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
44 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
45 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
46 Summary Firefighters must know the differences between the classes of foam, how to generate
foam, and how to apply foam most effectively Firefighter II
47 Review
Questions 1. What are the ways that fire fighting foam extinguishes and/or prevents fire? 2. Describe types of foam concentrates. 3. What are the methods by which foam may be proportioned? [Continued] Firefighter II
48 Review Questions 4. What are the types of portable foam proportioners and how do they work?
5. Describe the techniques used to apply foam. Firefighter II