FOAM FIRE STREAMS

1. FOAM FIRE STREAMS

2. MOTIVATION • Understanding how foam works in extinguishing different types of fires, and the principles of making different foams correctly, are essential to successful foam fire fighting operations. All too often, foam fire streams fail to accomplish their objective due to a lack of understanding and training on the part of the operator. Foam is an efficient firefighting tool that is gaining greater acceptance and use throughout the fire fighting community.

3. TERMINAL OBJECTIVE • The Firefighter II candidate shall correctly define or describe, in writing, how foam prevents or controls a hazard, the principles of foam generation, common problems associated with foam making, and the different types of foam concentrates used on various types of fuels.

4. HOW FOAM WORKS • Foam forms a blanket on the burning fuel. This blanket excludes oxygen and stops the burning process. The water in the foam is slowly released as the foam breaks down. This action provides a cooling effect on the fuel.

5. HOW FOAM WORKS • Smothering -Dilution / Reduction of 02 • Separating -Elimination of Fuel • Cooling -Reduction of Fuel Temp • Suppressing -Interruption of Chemical Chain Reaction Fuel Oxygen Heat ChainReaction

7. EFFECTIVENESS Fire fighting foam is especially effective on the two basic categories of flammable liquids: • Hydrocarbon fuels –petroleum-based products that float on water (i.e.: crude oil, fuel oil, gasoline, benzene, naphtha, jet fuel, and kerosene) • Polar solvents –flammable liquids that have an attraction for water, much like a positive magnetic pole attracts a negative pole (i.e.: alcohols, acetone, lacquer thinner, ketones, esters, and acids)

8. FLAMMABLE LIQUIDS • Hydrocarbons • Kerosene • Gasoline • Toluene • Methyl Ethyl Ketone • Polar Solvents • Ethanol • Acetone

9. FOUR ELEMENTS OF FOAM • Foam Concentrate. • Water (proportioned). • Air (aerated). • Mechanical Aeration.

11. FOAM TERMINOLOGY • Foam solution –Mixture of foam concentrate and water before the introduction of air. • Finished foam –Completed product after air is introduced into the foam solution. • Expansion ratio –Refers to the increase in volume of a foam solution when it is aerated. • Concentrate –Raw foam liquid as it rests in its storage container before the introduction of water and air. • Concentrate Percentage. • Foam proportioner –Device that introduces foam concentrate into the water stream to make the foam solution.

13. DEGREES OF EXPANSION FACTORS TO CONSIDER • Type of foam concentrate used • Accurate proportioning (mixing) of the foam concentrate in the solution • Quality of the foam concentrate • Method of aspiration

14. TYPES OF FOAM • Low-expansion –has an air/solution ratio up to 20 parts finished foam for every part of foam solution (20:1 ratio) • Medium-expansion –most commonly used at the rate 20:1 to 200:1 through hydraulically operated nozzle-style delivery devices • High-expansion –rate is 200:1 to 1000:1

16. COMPATIBILITY ISSUES CAUTION: Failure to match the proper foam concentrate with the burning fuel will result in an unsuccessful extinguishing attempt and could endanger firefighters. • Many foams that are intended for polar solvents may be used on hydrocarbon fires, but this should not be attempted unless the manufacturer of the particular concentrate specifically says this can be done.

17. CLASS A FOAM • Class A foam is a special formulation of hydrocarbon surfactants that reduce the surface tension of water in the foam solution. By doing so, this provides for better water penetration, thereby increasing its effectiveness. • It may be used with fog nozzles, aspirating foam nozzles, medium- and high- expansion devices, and compressed air foam systems (CAFS). • However, the concentrate is mildly corrosive and it is important to thoroughly flush equipment after use.

18. CLASS B FOAM • Class B foam is used to extinguish fires involving flammable and combustible liquids and also to suppress vapors from unignited spills of these liquids. • These concentrates are manufactured from either a synthetic or protein (animal) base. • It may be proportioned into the fire stream via a fixed system, an apparatus-mounted system, or by portable foam proportioning equipment.

19. CLASS B FOAM • Foams such as aqueous film forming foam (AFFF) and film forming fluoroprotein foams (FFFP) may be applied either with standard fog nozzles or with air-aspirating foam nozzles (all types). • The rate of application (minimum amount of foam solution that must be applied) for Class B foam varies depending on any one of several variables: Type of foam concentrate used Whether or not the fuel is on fire Type of fuel (hydrocarbon/polar solvent) involved Whether the fuel is spilled or in a tank Whether the foam is applied via either a fixed system or portable equipment

21. AFFF

22. CONCENTRATION LEVELS 1 Gallon AFFF Concentrate 99 Gallons of Water 100 Gallons 1% Foam Solution 3 Gallons AFFF Concentrate 97 Gallons of Water 100 Gallons 3% Foam Solution 6 Gallons AFFF Concentrate 94 Gallons of Water 100 Gallons 6% Foam Solution + + +

23. FOAM PROPORTIONING • Most fire fighting foam concentrates (except Class A foams) are intended to be mixed with 94 to 99.9% water. For example, when using 3% foam concentrate, 97 parts water and 3 parts foam concentrate equals 100 parts foam solution. For 6% foam concentrate, 94 parts water mixed with 6 parts foam concentrate equals 100% foam solution.

25. 4 WAYS FOAM IS PROPORTIONED • Induction –uses the pressure energy in the stream of water to draft foam concentrate into the fire stream. • Injection –uses an external pump or head pressure to force foam concentrate into the fire stream at the correct ratio in comparison to the flow. • Batch-mixing –adding foam concentrate to the apparatus water tank. • Premixing –premeasured portions of water and foam concentrate are mixed in a container.

26. FOAM PROPORTIONERS In general, foam proportioning devices operate by one of two basic principles: • The pressure of the water stream flowing through an orifice creates a venturi action that inducts (drafts) foam concentrate into the water stream. • Pressurized proportioning devices inject foam concentrate into the water stream at a desired ratio and at a higher pressure than that of water.

27. PROPORTIONING PROBLEMS • Mismatched Eductor & Nozzle. • Clogged Screens & Passages. • Partially Closed Nozzle. • Too Much Back Pressure. • Metering Valve Closed.

28. PROPORTIONING PROBLEMS • By-Pass Valve Open. • Incorrect Pump Pressure. • Temperature Below Pour Point (should be kept at anywhere between 10° F and 120° F) • Air Leaks. • Kinks in Hose.

29. IN-LINE FOAM EDUCTORS • Most common type used • Designed to be used either attached to the pump panel discharge outlet or connected at some point in the hose lay • The foam concentrate inlet to the eductor should not be more than 6 feet above the liquid surface of the foam concentrate

31. IN-LINE FOAM EDUCTORS

32. FOAM NOZZLE EDUCTORS • Operates on the same principle as the in-line eductor, however, this eductor is built into the nozzle rather than into the hoseline • May compromise firefighter safety should they be forced to retreat because they may have to leave their concentrate supplies behind

33. APPARTAUS-MOUNTED PROPORTIONERS Three various types of the various apparatus-mounted proportioning systems are installed: • Installed in-line eductors • Around-the-pump proportioners • Balanced pressure proportioners

34. LINE PROPORTIONING Eductor at Pump 95 gpm 150 ft. of 1½” hose 95 gpm 100 psi at nozzle Concentrate • A maximum of 150 ft. of 1½’’ hose between eductor & nozzle with a 95 gpm flow.

35. LINE PROPORTIONING EDUCTOR IN HOSELINE 2½” Inlet 1½” outlet 95 gpm Eductor Variable Flow Fog Nozzle 95 gpm 100 psi 250 ft. of 2½” hose 150 ft. of 1½” hose • Eductor and foam nozzle matched 95 gpm flow • Nozzle pressure 100 psi with valve fully open • Friction loss = 52.75 (250 ft. 2½” hose x 2.3/100 ft. = 5.75 ) • + ( 150 ft. 1½” hose x 31/100 ft. = 47) • Back pressure = elevation divided by 2.31 Water Supply

36. FOAM NOZZLE PROPORTIONING 1½” 95 gpm Foam Nozzle with Pickup Tube 100 psi 150 ft. of 1½” hose Water Supply • Foam nozzle with pickup tube - 95 gpm flow • Nozzle pressure 100 psi with valve fully open • Friction loss = 47 psi (150 ft. 1½” x 31 psi drop per 100 ft.) • Back pressure = Elevation divided by 2.31

37. BACK PRESSURE Nozzle Pressure Friction Loss in the Hose + Elevation Loss Back Pressure

38. MOTIVATION • The proficient use of foam fire streams and appliances are an essential part of many fire ground applications. It takes time and knowledge to set-up and discharge a foam fire stream. Quick and decisive action by firefighters to put a foam fire stream into action may make the difference as to whether or not an operation is successful. Constant training using foam fire streams and their appliances is essential to maintain a proficiency in foam use. This proficiency will enhance the efficiency and safety of any fire ground operation. The instructor must demonstrate the use of various foam appliances, and improvise using detergent and water where necessary to accomplish his/her training objectives.

39. OBJECTIVE • The Firefighter II candidate shall correctly list and describe, in writing, the seven types of foam concentrates, their characteristics, and their advantages / disadvantages.

40. TYPES OF FOAM CONCENTRATE • Protein Foam (3% and 6%) • Fluoroprotein Foam (3% and 6%) • Film Forming Fluoroprotein Foam (FFFP) (3% and 6%) • Aqueous Film Forming Foam (AFFF) (1%, 3%, and 6%)

41. TYPES OF FOAM CONCENTRATE • Alcohol - Resistant AFFF • (3% and 6%). • Medium and High Expansion Foam. • Class ‘A’ Foam.

42. PROTEIN FOAM • Use of protein foam started before World War II (mid 1930’s) • Regular protein foams are chemically broken down (hydrolyzed) protein solids. The end product of this chemical digestion is protein liquid concentrate.

43. PROTEIN FOAM • Disadvantages • Protein foam tends to mix with fuel • Application requires FF’s to use a close approach • Allowing protein foam to plunge into the fuel allows burning to continue & may splash the fuel, increasing the fire hazard

44. FLUOROPROTEIN FOAM • Synthetic detergent foams were developed in the 1950’s • Fluoroproteins were developed in the 1960’s

45. FLUOROPROTEIN FOAM • Are fortified with fluoronated surfactants. These surfactants enable the foam to shed, or separate from hydrocarbon fuels. This ability allows for direct foam application using a plunge technique. • FF’s can apply from a distance. • Can be injected at the base of a burning storage tank.

46. OBJECTIVE • Given the appropriate equipment, the Firefighter II candidate shall correctly assemble and operate a foam fire stream and shall correctly demonstrate the methods for applying a foam fire stream.

47. HANDLINE NOZZLES • IFSTA defines a handline nozzle as “any nozzle that one to three firefighters can safely handle and that flows less than 350 gpm.”

49. SOLID BORE NOZZLES • The use of solid bore nozzles is limited to certain types of Class A applications. In these applications, the solid bore nozzle provides an effective fire stream that has maximum reach capabilities.

50. FOG NOZZLES • Either fixed-flow or automatic fog nozzles can be used with foam solutions to produce a low-expansion, short-lasting foam. • This nozzle breaks the foam solution into tiny droplets and uses the agitation of water droplets moving through air to achieve its foaming action. • Best when used with AFFF and Class A foams. • Cannot be used with protein and fluoroprotein foams. • May be used with alcohol-resistant AFFF foams on hydrocarbon fires but should not be used on polar solvent fires.