Define Fire Stream. A stream of water, or other extinguishing agent, after it leaves the fire hose and nozzle until it reaches the desired point

Transcription

1 Nozzles and Streams

2 Define Fire Stream A stream of water, or other extinguishing agent, after it leaves the fire hose and nozzle until it reaches the desired point

3 Identify the Purposes of a Fire Stream Applying water or foam directly to burning material to reduce its temperature Applying water or foam over an open fire to reduce the temperature so firefighters can advance hand lines closer to effect extinguishment Reducing high atmospheric temperature Dispersing hot smoke and fire gases from a heated area by using a fire stream Creating a water curtain to protect firefighters and property from heat Creating a barrier between a fuel and a fire by covering with a foam blanket

4 Identify the Various Uses of Water as an Extinguishing Agent Advantages Water is an efficient, plentiful, and inexpensive extinguishing agent. Greater heat absorbing capacity than other common extinguishing agents One BTU is the amount of heat required to raise the temperature of one pound of water one degree F Cools fuel below ignition temperature A relatively large amount of heat is required to vaporize water to steam 970 BTU s are required to vaporize water, changing it to steam The greater the surface area of the water exposed, the more rapidly heat will be absorbed Water converted to steam occupies 1700 times the original volume occupied by the liquid Displaces hot gases, smoke and other products of combustion

5 Water as Steam At 212ºF (100ºC) water expands to approximately 1,700 times its original volume. Steam absorbs more heat faster, cooling fuel below ignition temperature. Steam displaces hot gases, smoke, and other products of combustion. In some cases, steam may smother fire by excluding oxygen. 10 feet (3m) 20 cubic feet (0.57 m 3 ) of 500 F (260 C) converts to 48,000 feet (1 359 m) of steam 96 feet (29 m)

6 Identify the Various Uses of Water as Disadvantages an Extinguishing Agent Water has a considerable amount of surface tension Will not readily penetrate certain porous materials Will react with certain combustible materials Freezing will occur at 32 0 F (0 0 C) Water has low viscosity; it will not cling or readily coat materials May conduct electricity under certain conditions

7 Identify the Types of Fire Stream Nozzles Solid Stream Discharge Orifice No Greater Than Half Size of Hoseline Smooth, Cylindrical Bore Length One to One and One-half Times its Diameter

8 Identify the Types of Fire Stream Nozzles Solid Stream Flow rate is dependant on the velocity of the stream and size of discharge opening Increase of size of discharge orifice or velocity will increase flow Longer reach than other types of streams; The greater the discharge pressure, the greater the reach Maximum horizontal reach is attained at an angle of 32 degrees Vertical reach into structures is best at a degree angle Greatest vertical reach is a 90 degree angle Wind will affect stream shape and reach Reduced problem of steam burns to firefighters and trapped civilians as a result of disturbance to the normal thermal layering of heat and gases during interior structural attack Operating pressures 50 psi on handlines 80 psi on master stream devices

9 Identify the Types of Fire Stream Nozzles Fog Stream / Straight Stream

10 Identify the Types of Fire Stream Nozzles Fog Stream / Straight Stream A fog stream is a patterned stream composed of fine water droplets Greater heat absorption due to more surface area of water May be used in close proximity to energized electrical equipment Has less reach and penetrating power than solid streams Improper use during interior attacks can Spread the fire Create heat inversion Cause steam burns to firefighters and trapped civilians

11 Identify the Types of Fire Stream Nozzles Fog Stream / Straight Stream Flow rate is dependent on type of nozzle, pressure and stream pattern Constant gallonage nozzles One flow rate at a given discharge pressure Adjustable gallonage nozzles Allows one of several preset gallon settings to be selected Automatic nozzles Discharge a wide range of flows depending on the pressure being supplied to the nozzle

12 Identify the Types of Fire Stream Nozzles Fog Stream / Straight Stream Can produce variable stream patterns Wide angle fog 45 to 80 Narrow angle fog Straight stream 15 to 45 A very narrow fog pattern with broken water dropets Not to be confused with a solid stream

13 Identify the Types of Fire Stream Nozzles Fog Stream / Straight Stream Wider the pattern, shorter the reach Low nozzle pressure will reduce velocity, reach and volume Once maximum reach is attained, increases in nozzle pressure have little effect on reach and volume

14 Identify the Types of Fire Stream Nozzles Broken stream

15 Identify the Types of Fire Stream Nozzles Broken stream Limited to special applications Designed for a specific use Solid stream broken into coarsely divided water droplets Droplets are larger than fog stream droplets and have better penetration

16 Identify the Water Flow/GPM of Handlines and Master Streams Hand Lines - Generally range from GPM ½ to 1 diameter hand lines (small) GPM 1 to 2 diameter hand lines (medium) GPM 2½ - 3 diameter hand lines (medium/large) GPM Master Stream - Discharge is greater than 350 GPM

17 Identify the Safe Operation of Fire Stream Nozzles Watch for over-pressurization Operate hand lines with minimum of two firefighters Remain aware of fire conditions Follow personal safety procedures Hand lines should be operated with two or more firefighters Methods of preventing damage Open nozzles and other appliances slowly Close nozzles and other appliances slowly Avoid dropping nozzles and appliances In cold weather, leave nozzles cracked open to prevent freezing

18 Define Nozzle Reaction The force of nature that makes the nozzle move in the opposite direction of the water flow. The nozzle operator must counteract the thrust exerted by the nozzle to maintain control Newton s Third Law: For every action, there is an equal and opposite reaction The greater the nozzle discharge pressure, the greater the nozzle reaction

19 Define Water Hammer and Techniques for Its Prevention Sudden stopping of water flow resulting in surge of energy in the opposite direction

20 Define Water Hammer and Techniques for Its Prevention Effects Broken pipes, hoses, pumps and hydrants Prevention Open and close valves slowly Cause Rapid/sudden closing of nozzles or valves

21 Identify results that are obtained when the proper application of a fire stream is accomplished Thermal layer is maintained Steam conversion Temperature reduction Fire reduction / extinguishment (darkens down)

22 Identify Methods of Water Application Direct Apply water directly on burning fuels: Most efficient use of water Should be applied in short bursts Application of water until the fire "darkens down"

23 Identify Methods of Water Application Indirect Fog stream directed at ceiling, into superheated atmosphere results in the production of large quantities of steam Not desirable when victims may yet be present Used where spread of fire into uninvolved spaces cannot be contained

24 Identify Methods of Water Application Combination A ceiling level attack combined with an direct attack on burning materials at the floor level Nozzle is rotated with stream edge reaching the ceiling, wall, floor and opposite wall T Z O

25 Identify the Use of Various Nozzles Carried on Fire Apparatus Fog Immediate reduction of heat Helps to avoid flashover Adjustable stream pattern Wide Angle Fog Narrow Angle Fog Straight Stream Smooth bore nozzle Longer reach than a combination nozzle Capable of deeper penetration into burning material Operate at a lower pressure Less disturbance of the thermal layering Easier to see the pathway than a fog stream Piercing nozzle Used to make holes in sheet metal, aircraft, or building walls Extinguish behind these surfaces Cellar nozzle/bresnan distributor nozzles: Fires in cellars and other inaccessible places Water curtain Deliver a flat screen of water to form a protective sheet of water

26 Identify the Procedures for Cleaning, Maintaining and Inspecting Nozzles Inspecting Check the gasket Check for external damage Check for internal damage and debris Check for ease of operation Cleaning and Maintaining Clean with soap and water using a soft bristle brush Replace the gasket Clean and lubricate any moving parts that stick according to manufacturer s recommendations

27 Identify the Principals of Both Class A and Class B Foam as an Extinguishing Agent Components of foam Air Foam Solution Water Concentrate Water Foam Proportioner Finished Foam Mechanical Agitation Foam Concentrate

28 Identify the Principals of Both Class A and Class B Foam as an Extinguishing Agent Types of foam concentrate Class A Are used on wildland and structural fires Contain hydrocarbon surfactants Reduce water tension in foam solution Coat and insulate fuels May be applied with a variety of nozzles, expansion devices, and CAFS Have supercleaning characteristics Are mildly corrosive

29 Identify the Principals of Both Class A and Class B Foam as an Extinguishing Agent Types of foam concentrate Class B Are used on fires involving flammable and combustible liquids Are used to suppress unignited vapors Are made from fluorosurfactants, animal proteins, and combinations of these Are generally formulated for either hydrocarbons or polar solvents

30 Class B Fuels Hydrocarbon Fuels Petroleum based Float on water Examples Crude oil Fuel oil Gasoline Benzene Naphtha Jet fuel Kerosene Polar Solvent Fuels Flammable liquids Mix with water Examples Alcohols Esters Acids Acetone Lacquer thinner Ketones

31 Class B Foam Types Protein Fluoroprotein Film Forming Fluoroprotein Contain natural proteins Bio-degradable Better used on deep pools of fuel

32 Class B Foam Types Aqueous Film Forming Foam (AFFF) Alcohol Resistant Film Forming Foam (AR-AFFF) Synthetic foaming agents Film is formed on the surface of the flammable liquid by the foam solution as it drains from the foam blanket Best used on spills

33 How AFFF Works Water drained from foam blanket floats on hydrocarbon fuel spills. This light water send an air-excluding film ahead of foam blanket. Foam Aqueous Film Fuel

34 Identify the Methods by Which Foam Prevents or Controls a Hazard Separates barrier between fuel and fire Cooling reduces the temperature of the fuel Suppressing holds down flammable vapors Tension / Penetration reduces surface tension allowing for greater penetrating ability (Class A)

35 Proportioning Concentrations 3% foam = 97 parts of water + 3 parts foam concentrate Class B foams are normally mixed in proportions of 1% to 6%. Class A foams can be mixed across a wider range of proportions than Class B foams. 3% concentrate is normally used for hydrocarbon fuels. 6% concentrate is normally used for polar solvent fuels. Multipurpose foam is often mixed at 3% concentration regardless of the fuel. Dry (thick) foam used for exposure protection and fire breaks can be produced by increasing the percentage of foam concentrate. Wet (thin) foam that will sink below the surface of the fuel can be produced by decreasing the percentage of foam concentrate.

36 Identify the Necessary Equipment for the Application of Class A and Class B Foam Eductors Venture principle to pick up the foam In-line water always piped through the eductor By-pass separate waterway to by-pass the waterway

37 Identify the Necessary Equipment for the Application of Class A and Class B Foam Proportioner The device that mixes the foam concentrate into the fire stream in the proper percentage Fixed Portable Should be located less then 6 from foam tank/source

38 Identify the Necessary Equipment for the Application of Class A and Class B Foam Nozzles Smooth Bore Fog Air Aspirating Water Aspirating Mechanical Blower Compressed Air Foam Systems (CAFS)

39 Identify the Principle by Which Foam is Picked up (educted) Generated Pressure energy in the water stream drafts concentrate into the fire stream Proper mixture (proportioned) An external pump or head pressure forces concentrate into the fire stream Mixed with air (aerated)(nozzle) Nozzle designed to draw air into the foam mix to allow for a greater expansion of the foam mixture

40 Identify the Techniques of Applying Class B Foam Bank-in or Roll-On Rain-Down or Snowflake Bank-Back, Bounce-Off, Bank-Down or Deflection

41 Identify Common Causes for Poor Foam Generation and How to Correct It Eductor and nozzle flow ratings do not match Air leaks at fittings cause a loss of suction Foam passages are clogged due to improper cleaning Nozzle is not fully open Hose lay on discharge side of eductor is too long Hose is kinked and stops flow Nozzle is too far above eductor Mixture is too viscous to pass through eductor

42 Identify the Procedures for Inspecting, Cleaning and Maintaining Foam Appliances Inspecting; Check the gasket Check for external damage Check for internal damage and debris Check for ease of operation Cleaning and Maintaining The foam appliance should be flushed with water at the end of each use Clean with soap and water using a soft bristle brush Replace the gasket Clean and lubricate any moving parts that stick according to manufacturer s recommendations

43 Q & A