Chapter 11 Nozzles Fire Streams and Foam Introduction

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Chapter 11 Nozzles, Fire Streams, and Foam

Chapter 11 Nozzles, Fire Streams, and Foam

Introduction • Fires usually extinguished by water • Foam added to improve water’s extinguishment

Introduction • Fires usually extinguished by water • Foam added to improve water’s extinguishment ability – For fires where water ineffective • Water and foam delivered using nozzles and fire streams • Nozzle selection important – Each fire situation requires different appliance 11. 2

Definition of Fire Stream • Fire stream: extinguishing agent that leaves the nozzle and

Definition of Fire Stream • Fire stream: extinguishing agent that leaves the nozzle and flows toward its target • Four elements affecting the stream: – – Pump Water Hose Nozzle • Proper stream has sufficient volume, pressure, and direction to reach its target 11. 3

Nozzles • Nozzles: appliances that allow application of extinguishing agent – Two types: solid

Nozzles • Nozzles: appliances that allow application of extinguishing agent – Two types: solid stream and fog • Combination nozzles: straight stream or adjustable spray patterns • Nozzle pressure: pressure required for effective nozzle operation – Relates to flow and reach • Nozzle flow: amount of water a nozzle provides at a given pressure 11. 4

Figure 11 -1 Nozzles showing the stream shape for straight, solid, and wide pattern

Figure 11 -1 Nozzles showing the stream shape for straight, solid, and wide pattern streams. 11. 5

Nozzles (cont’d. ) • Nozzle reach: distance the water will travel after leaving the

Nozzles (cont’d. ) • Nozzle reach: distance the water will travel after leaving the nozzle • Nozzle reach a function of water pressure – Affected by stream shape, water pressure, wind direction, gravity, air friction • Stream shape (stream pattern): configuration of droplets of water as they leave the nozzle • Nozzle reaction: nozzle moves in opposite direction of water flow 11. 6

Solid Tip or Stream • Deliver unbroken stream of water • Solid stream nozzle

Solid Tip or Stream • Deliver unbroken stream of water • Solid stream nozzle delivers water as a solid cone of water – Large droplets when bounced off wall, ceiling • Flow a factor of tip size at a certain nozzle pressure • Minimal effect of room’s thermal balance • Disadvantages: lack of volume control, lack of fog protection, higher nozzle reaction 11. 7

Fog Nozzles • Deliver fixed spray pattern or variable combination pattern – Straight stream

Fog Nozzles • Deliver fixed spray pattern or variable combination pattern – Straight stream and spray patterns • Fog provides better heat absorption, but can change to steam • Excellent tools for hydraulic ventilation • Large quantities of smoke removed by aiming fog cone out an open window – Can also draw heat from the fire 11. 8

Figure 11 -6 Variable combination fog nozzle patterns. From top to bottom: straight stream,

Figure 11 -6 Variable combination fog nozzle patterns. From top to bottom: straight stream, narrow fog, and wide fog. 11. 9

Figure 11 -7 Parts of a fog nozzle. 11. 10

Figure 11 -7 Parts of a fog nozzle. 11. 10

Straight Stream • Creates a hollow type stream – Similar to solid stream pattern

Straight Stream • Creates a hollow type stream – Similar to solid stream pattern • Straight stream pattern must pass around the baffle of the nozzle – Creates an opening in the pattern – May allow air into the stream and reduce its reach • Newer designs have hollow effect from the tip – Short distance to refocus the stream to create solid stream with good reach and penetration 11. 11

Figure 11 -11 Comparison of (A) straight and (B) solid streams at tip. 11.

Figure 11 -11 Comparison of (A) straight and (B) solid streams at tip. 11. 12

Special Purpose • Not often used • Cellar nozzles and Bresnan distributors: – Fight

Special Purpose • Not often used • Cellar nozzles and Bresnan distributors: – Fight localized fires in basements when firefighters cannot make direct attack • Piercing nozzles originally designed to penetrate the skin of aircraft – Modified to pierce through building walls and floors • Water curtain nozzle – Sprays water to protect against heat exposure 11. 13

(A) (B) Figure 11 -12 (A) Cellar nozzle and (B) Bresnan distributor. 11. 14

(A) (B) Figure 11 -12 (A) Cellar nozzle and (B) Bresnan distributor. 11. 14

Figure 11 -13 Piercing nozzle. Figure 11 -14 Water curtain nozzle. 11. 15

Figure 11 -13 Piercing nozzle. Figure 11 -14 Water curtain nozzle. 11. 15

Nozzle Operations • Solid tip nozzles easy to operate – Nozzle size and tip

Nozzle Operations • Solid tip nozzles easy to operate – Nozzle size and tip selected to match desired flow – Carry smaller nozzle tips in pocket • Fog nozzles with rotating valves common for wildland firefighting – Gallonage and pattern adjustments detected in the dark because nozzle clicks at each position • Fog nozzles have more applications than smooth bore nozzles – Considered more effective 11. 16

Operating Hoselines • Chapter 10 covers: – – – Advancing hoselines, initial nozzle operation

Operating Hoselines • Chapter 10 covers: – – – Advancing hoselines, initial nozzle operation Straightening the hose Properly spacing firefighters on same side of line Bleeding off air from hose and nozzle Selecting proper pattern • Most hoselines operated from crouching or kneeling position – Lying, standing, or sitting positions also used 11. 17

Small-Diameter Handlines • Small-diameter handlines: – Typically 1½, 1¾, or 2 inches in diameter

Small-Diameter Handlines • Small-diameter handlines: – Typically 1½, 1¾, or 2 inches in diameter – Flow from 100 to over 250 gpm • When flowing at lower volumes, operated by one person – Larger volumes require two people • Fog and solid tip nozzles can be used for small lines – Small lines popular because of ease of mobility, number of personnel, extinguishing ability 11. 18

Medium-Diameter Handlines • Medium-diameter hose for handlines: – 2½-inch or 3 -inch hose –

Medium-Diameter Handlines • Medium-diameter hose for handlines: – 2½-inch or 3 -inch hose – Solid tip and fog nozzles – Flow from 165 to 325 gpm • 2½-inch hose is standard size hoseline – Many departments use 1¾-inch and 2 -inch for attack • Increased maneuverability – Large commercial structures or buildings with high fire loading require increased gpm flow of 2½-inch line • Require two or more personnel to operate 11. 19

Master Stream Devices • Master stream devices capable of 350 gpm • Main artillery

Master Stream Devices • Master stream devices capable of 350 gpm • Main artillery of fire service • Used when large volumes of water required • Must be apparatus-mounted or secured properly • Require only one person to operate – Lack of mobility 11. 20

Stream Application, Hydraulics, and Adverse Conditions • Applications of fire streams vary according to

Stream Application, Hydraulics, and Adverse Conditions • Applications of fire streams vary according to method of fire attack, conditions encountered – Including environmental factors and water supply • Fire streams must have proper pressure and flow • Firefighters must understand hydraulics • Improper hydraulic calculations are the leading cause of poor fire streams 11. 21

Direct, Indirect, and Combination Attack • Direct fire attack – Aim the flow of

Direct, Indirect, and Combination Attack • Direct fire attack – Aim the flow of water directly at the seat of the fire – Used on deep-seated fires that require penetration • Indirect fire attack – Apply a fog stream into a closed room – Convert water into steam to extinguish the fire • Combination attack – Typical attack in structural firefighting 11. 22

Figure 11 -20 Firefighter directly attacking a fire. 11. 23

Figure 11 -20 Firefighter directly attacking a fire. 11. 23

Figure 11 -21 Firefighter using indirect attack by applying water into room and then

Figure 11 -21 Firefighter using indirect attack by applying water into room and then closing the door. 11. 24

Figure 11 -22 One cubic foot of water in liquid form expands 1, 700

Figure 11 -22 One cubic foot of water in liquid form expands 1, 700 times when converted to steam at 212°F. 11. 25

Figure 11 -23 Firefighter using combination fire attack directing the stream from the ceiling

Figure 11 -23 Firefighter using combination fire attack directing the stream from the ceiling to the fire with a circular, “Z” or “T” motion. 11. 26

Basic Hydraulics, Friction Loss, and Pressure Losses in Hoselines • Hydraulics: study of fluid

Basic Hydraulics, Friction Loss, and Pressure Losses in Hoselines • Hydraulics: study of fluid in motion • Pressure: force divided over an area • Flow: rate and quantity of water delivered • Friction loss: loss in pressure due to friction • Discharge pressure of a pump: EP = NP + FL ± E + SA 11. 27

Figure 11 -27 Example for friction loss and engine pressure calculations. 11. 28

Figure 11 -27 Example for friction loss and engine pressure calculations. 11. 28

Adverse Conditions • Two types: natural and man-made • Natural: – Wind and wind

Adverse Conditions • Two types: natural and man-made • Natural: – Wind and wind direction • Breaks up stream and deflects it from its target – Rain, snow, hail, tree branches, wires, etc. deflect and break up hose streams – Gravity and air friction: • Move closer to the target or to a better position 11. 29

Types of Foam and Foam Systems • Class B foam: specially formulated concentrated liquid

Types of Foam and Foam Systems • Class B foam: specially formulated concentrated liquid foaming agents – Creates a blanket that cools and smothers the fire – Seals in vapors • Class A foam: detergent or soap-based surfactants – Penetrate ordinary combustible materials – Keeps fuel wet and reduces its ability to 11. 30 burn

Foam Characteristics • Protein foam: natural protein materials with metallic salts • Fluoroprotein foam:

Foam Characteristics • Protein foam: natural protein materials with metallic salts • Fluoroprotein foam: improved protein foam with fluorinated surfactant added • Alcohol-resistant foam: contains a polymer – Forms a layer between burning surface and foam • Fluoroprotein film-forming foam (FFFP): – Combines protein with film-forming fluorosurfactants • Detergent-type foams: synthetic surfactants break surface tension of water 11. 31

Classification of Fuels • Foams used for Class A and B fires • Specific

Classification of Fuels • Foams used for Class A and B fires • Specific considerations affect their use 11. 32

Class A • Piles of Class A materials extinguished using a wetting agent •

Class A • Piles of Class A materials extinguished using a wetting agent • Foamy water solution has the ability to cling to sides of objects • Used to protect homes in urban interface areas during wildland fires • Disadvantages: – Cost of equipment and agent, environmental effects – Fire investigation lab tests, difficult salvage operations 11. 33

Class B • Class B fuels: hydrocarbons and polar solvents – Firefighters do not

Class B • Class B fuels: hydrocarbons and polar solvents – Firefighters do not use foam • Hydrocarbons: – Examples: heating oil, gasoline, paraffin, asphalt – Not miscible; foam is best method to extinguish • Polar solvents: – Examples: alcohols, lacquer thinners, acetone – Normal foams break down when used on fires involving these mixtures – Special foams create a polymeric barrier 11. 34

Figure 11 -29 (A) AFFF applied on Class B fuel. Note the film barrier

Figure 11 -29 (A) AFFF applied on Class B fuel. Note the film barrier on the surface. 11. 35

Figure 11 -31 Polar solvent or alcohol-type foam applied on Class B polar solvent

Figure 11 -31 Polar solvent or alcohol-type foam applied on Class B polar solvent fuel. Note the polymeric film barrier on the surface. 11. 36

Application of Foam • Requires a device to proportion, meter, or mix foam concentrate

Application of Foam • Requires a device to proportion, meter, or mix foam concentrate into the water – Air added to foam solution • Eductor: common proportioner – Works on Venturi principle – Must have proper gpm flow, correct pressure, be clean, not have back-pressure situations • Compressed air foam systems (CAFS): – Concentrate in separate foam tank – Concentrate metered by microprocessor 11. 37

Figure 11 -33 Foam eductor using the venturi principle. 11. 38

Figure 11 -33 Foam eductor using the venturi principle. 11. 38

Bank-In Technique Figure 11 -40 The bank-in technique of foam application. 11. 39

Bank-In Technique Figure 11 -40 The bank-in technique of foam application. 11. 39

Bank-Back Technique Figure 11 -41 The bank-back technique of foam application. 11. 40

Bank-Back Technique Figure 11 -41 The bank-back technique of foam application. 11. 40

Raindown Technique Figure 11 -42 The raindown technique of foam application. 11. 41

Raindown Technique Figure 11 -42 The raindown technique of foam application. 11. 41

Fog Nozzles versus Foam Nozzles • Some nozzles combined all foam-making steps • Modern

Fog Nozzles versus Foam Nozzles • Some nozzles combined all foam-making steps • Modern foam nozzles aspirate air and apply foam to the fuel – Air vents built into the nozzle – Designed for low and medium expansion – Recommended with protein and fluoroprotein foams • Fog nozzles can be used with foam – Clip-on foam nozzle adapters attach to the fog nozzle • Three techniques: bank-in, bounce-off, raindown 11. 42

Nozzle and Foam Equipment Maintenance • Nozzles and foam appliances must be cleaned and

Nozzle and Foam Equipment Maintenance • Nozzles and foam appliances must be cleaned and maintained regularly • Follow manufacturer guidelines and department policies • Guidelines and policies should include: – – Cleaning and maintenance schedule Necessary skill level of firefighter Documentation procedures Replacement and repair process 11. 43

Lessons Learned • Fire streams: water that leaves a nozzle and heads toward the

Lessons Learned • Fire streams: water that leaves a nozzle and heads toward the target – Solid tip and fog nozzles – Nozzle should match fire conditions and department resources • Correct hydraulics calculations require understanding pressure and friction loss • When fuels not compatible with water, other agents are used • Foam requires special equipment 11. 44