Essentials of Fire Fighting 5 th Edition Chapter

Essentials of Fire Fighting, 5 th Edition Chapter 14 — Fire Streams Firefighter I

Chapter 14 Lesson Goal • After completing this lesson, the student shall be able to effectively operate a solid stream nozzle, fog stream nozzle, and broken stream nozzle following the policies and procedures set forth by the authority having jurisdiction (AHJ). Firefighter I 1

Specific Objectives 1. List methods that are used with fire streams to reduce the heat from a fire and provide protection to firefighters and exposures. 2. Discuss the extinguishing properties of water. (Continued) Firefighter I 2

Specific Objectives 3. Describe friction loss. 4. Define water hammer. 5. Distinguish among characteristics of fire stream sizes. (Continued) Firefighter I 3

Specific Objectives 6. Discuss types of streams and nozzles. 7. Discuss handling handline nozzles. 8. Describe types of nozzle control valves. 9. List checks that should be (Continued) included in nozzle inspections. Firefighter I 4

Specific Objectives 10. (Skill 11. (Skill 12. (Skill Operate a solid-stream nozzle. Sheet 14 -I-1) Operate a fog-stream nozzle. Sheet 14 -I-2) Operate a broken-stream nozzle. Sheet 14 -I-3) Firefighter I 5

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 6

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 7

How Water Extinguishes Fire • Primary way is cooling • Smothering by diluting or excluding oxygen Firefighter I 8

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 9

Heat Absorption • Latent heat of vaporization • Expansion capability • Effective extinguishment with water generally requires steam production (Continued) Firefighter I 10

Heat Absorption • Water absorbs more heat when converted to steam than when heated to boiling point Firefighter I 11

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 12

Friction Loss • That part of total pressure lost while forcing water through pipes, fittings, fire hose, and adapters (Continued) Firefighter I 13

Friction Loss • When water flows through hose, couplings, appliances, its molecules rub against insides, producing friction • Slows water flow, reduces its pressure (Continued) Firefighter I 14

Friction Loss • Loss of pressure in hoseline between pumper and nozzle is most common example • Measuring friction loss • Affected by velocity of water and characteristics of hose layouts (Continued) Firefighter I 15

Friction Loss • Generally, the smaller the hose diameter and longer the hose lay, the higher the friction loss at a given pressure, flow volume Firefighter I 16

Factors Increasing Friction Loss • • • Rough linings in fire hose Damaged hose couplings Kinks/sharp bends in hose More adapters than necessary Hoselines longer than necessary Hose diameter too small for volume needed Firefighter I 17

Elevation Loss/Gain • Elevation — Position of nozzle above or below pumping apparatus • Elevation pressure — Gain/loss in hoseline pressure caused by gravity when there is difference in elevation (Continued) Firefighter I 18

Elevation Loss/Gain • Pressure loss — When nozzle is above fire pump • Pressure gain — When nozzle is below pump Firefighter I 19

Water Hammer (Continued) Firefighter I 20

Water Hammer • When flow of water through fire hose or pipe is suddenly stopped, shock wave produced when moving water reaches end of hose and bounces back • Pressure surge referred to as water hammer (Continued) Firefighter I 21

Water Hammer • Sudden change in direction creates excessive pressures that can cause damage to water mains, plumbing, fire hose, hydrants, fire pumps • Can often be heard as distinct clank • To prevent when water flowing, close components slowly Firefighter I 22

Identifying Fire Streams • • By size and type Size = Volume of flowing per minute Type = specific pattern/shape of water Rate of discharge measured in gallons per minute (gpm) or liters per minute (L/min) Firefighter I 23

Fire Stream Classifications • Low-volume stream • Handline stream • Master stream Firefighter I 24

Fire Stream Considerations • Volume discharged determined by design of nozzle, pressure at nozzle • To be effective, stream must deliver volume of water sufficient to absorb heat faster than it is being generated (Continued) Firefighter I 25

Fire Stream Considerations • Type of fire stream indicates specific pattern/shape of water stream • Requirements of effective streams • Requirements of all streams Firefighter I 26

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 27

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 28

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 29

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 30

Advantages of Solid Streams • Produce less steam conversion than fog nozzles • Can be used to apply compressed-air foam Firefighter I 31

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 32

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 33

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 34

Fog Stream • Nozzles permit settings of straight stream, narrow-angle fog, and wideangle fog • Nozzles should be operated at designed nozzle pressure (Continued) Firefighter I 35

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 36

Fog Stream • Shorter reach makes fog streams less useful for outside, defensive fire fighting operations • Well suited for fighting interior fires Firefighter I 37

Fog Stream: Waterflow Adjustment • Two types of nozzles control rate of water flow through fog nozzle • Manually adjustable nozzles • Automatic nozzles Firefighter I 38

Fog Stream: Nozzle Pressure • Combination nozzles designed to operate at different pressures • Designated operating pressure for most combination nozzles is 100 psi (700 k. Pa) (Continued) Firefighter I 39

Fog Stream: Nozzle Pressure • Nozzles with other designated operating pressures available • Setbacks of nozzles with lower operating pressures Firefighter I 40

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 41

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 42

Broken Stream • One that has been broken into coarsely divided drops • While solid stream may become broken stream past point of breakover, true broken stream takes on that form as it leaves nozzle • Cellar nozzle is an example Firefighter I 43

Advantages of Broken Streams • Absorb more heat per gallon (liter) than solid stream • Have greater reach, penetration than fog stream • Can be effective on fires in confined spaces Firefighter I 44

Disadvantages of Broken Streams • May have sufficient continuity to conduct electricity • Stream may not reach some fires Firefighter I 45

Handline Nozzles • Differing designs cause each one to handle somewhat differently when operated at recommended pressure • Those with variable patterns may handle differently in different settings (Continued) Firefighter I 46

Handline Nozzles • The water pattern produced by nozzle may affect ease of operation • Nozzles not always easy to control at/above standard operating pressures Firefighter I 47

Solid-Stream Nozzles • When water flows from nozzle, reaction equally strong in opposite direction, thus a force pushes back on person handling hoseline (Continued) Firefighter I 48

Solid-Stream Nozzles • Reaction caused by velocity, flow rate, discharge pattern of stream • Reaction can make nozzle difficult to handle • Increasing nozzle discharge pressure, flow rate increases nozzle reaction Firefighter I 49

Fog Stream Nozzles • When water is discharged at angles from center line of nozzle, reaction forces may counterbalance each other, reduce nozzle reaction • Balancing of forces is why a nozzle set on wide-angle fog handles more easily than straight-stream pattern Firefighter I 50

Nozzle Control Valves • Enable operator to start, stop, or reduce flow of water while maintaining effective control of nozzle • Allow nozzles to open slowly so operator can adjust as nozzle reaction increases (Continued) Firefighter I 51

Nozzle Control Valves • Also allow nozzles to be closed slowly to prevent water hammer • Three main types Firefighter I 52

Ball Valve • Most common • Provides effective control during nozzle operation with minimum effort (Continued) Firefighter I 53

Ball Valve • Ball, perforated by smooth waterway, is suspended from both sides of nozzle body and seals against seat • Ball can be rotated up to 90 degrees by moving valve handle backward to open and forward to close (Continued) Firefighter I 54

Ball Valve • Nozzle will operate in any position between fully closed, fully open • Operating nozzle with valve in fully open position gives maximum flow, performance Firefighter I 55

Slide Valve • Cylindrical slide valve control seats movable cylinder against shaped cone to turn off flow of water (Continued) Firefighter I 56

Slide Valve • Flow increases/decreases as shutoff handle is moved to change position of sliding cylinder relative to cone • Stainless steel slide valve controls flow of water through nozzle without creating turbulence (Continued) Firefighter I 57

Slide Valve • Pressure control compensates for increase/decrease in flow by moving baffle to develop proper tip size, pressure Firefighter I 58

Rotary Control Valve • Found only on rotary fog nozzles • Consists of exterior barrel guided by screw that moves it forward/backward, rotating around interior barrel • Major difference between rotary control and other valves is they also control discharge pattern of stream Firefighter I 59

Nozzle Inspections • Swivel gasket for damage or wear; • • replace worn or missing gaskets External damage to the nozzle Internal damage and debris Ease of operation of the nozzle parts Pistol grip (if applicable) is secured to the nozzle Firefighter I 60

Summary • To fight fires safely and effectively, firefighters must know the capabilities and limitations of all the various nozzles and extinguishing agents available in their departments. (Continued) Firefighter I 61

Summary • They must understand the effects that wind, gravity, velocity, and friction have on a fire stream once it leaves the nozzle. (Continued) Firefighter I 62

Summary • Firefighters must know what operating pressure their nozzles require and how the nozzles can be adjusted during operation. Firefighter I 63

Review Questions 1. What are the ways that water can extinguish fire? 2. Define friction loss, elevation loss/gain, and water hammer. 3. What factors can increase friction loss in fire hose? (Continued) Firefighter I 64

Review Questions 4. What are three size classifications of fire streams? 5. What is the difference between a solid stream and a fog stream? Firefighter I 65