Chapter 14— Fire Streams

14–2

Chapter 14 Lesson Goal

After completing this lesson, the student shall be able to effectively operate a solid stream nozzle, fog stream nozzle, & broken stream nozzle & effectively apply firefighting foam using various foam types, concentrates, & delivery devices

14–3

DISCUSSION QUESTION

What is a fire stream?

14–4

Methods to Reduce Heat and Provide Protection

• Applying water or foam directly onto burning material to reduce its temperature

• Applying water on full fog in front of a fire to protect FFs from radiant heat & advance handlines

• Reducing high atmospheric temperature

(Continued)

14–5

Methods to Reduce Heat and Provide Protection

• Dispersing hot smoke & fire gases from a heated area

• Wetting exposures to protect them from radiant heat

• Creating a barrier between a fuel & a fire by covering the fuel w/ a foam blanket

14–6

How Water Extinguishes Fire

• Primary way is cooling

• Smothering by diluting or excluding oxygen

14–7

Heat Absorption

• When heated to boiling point, water absorbs heat

• Visible form of steam is called condensed steam

• Components of heat absorption

Heat required to raise temperature of a substance

The additional heat required to change state

• Specific heat: amount of heat energy required to raise temperature of a specified mass of a substance by 1°

Measured in BTU’s & calories

(Continued)

14–8

Heat Absorption

• Latent heat of vaporization: Quantity of heat absorbed by a substance at the point at which it changes from a liquid to a vapor

• Expansion capability (1700:1)

• Effective extinguishment w/ water generally requires steam production

(Continued)

14–9

Heat Absorption

Water absorbs more heat when converted to steam at 212°F (expands 1700:1) than when heated to boiling point

14–10

Characteristics of Water Valuable for Fire Extinguishment

• Water attacks fire in several ways

• Also assists the ventilation process

14–11

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

14–12

Friction Loss

That part of total pressure lost while forcing water through pipes, fittings, fire hose, & adapters

(Continued)

14–13

Friction Loss

• When water flows through hose, couplings, appliances, its molecules rub against insides, producing friction

• Slows water flow, reduces its pressure

(Continued)

14–14

Friction Loss

• Loss of pressure in hoseline between pumper & nozzle is most common example

• Measuring friction loss

• Affected by velocity of water & characteristics of hose layouts

(Continued)

14–15

Friction Loss

• Generally, the smaller the hose diameter & longer the hose lay, the higher the friction loss

• Elevation gain – increases friction loss

Add 5 psi (40 kPa) per floor

• Elevation loss – reduces friction loss

Deduct 5 psi (40 kPa) per floor

Pump

Discharge

14–16

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

14–17

DISCUSSION QUESTION

What can be done to reduce friction loss during a fire ground operation?

14–18

Water Hammer

(Continued)

14–19

Water Hammer

• When flow of water through fire hose or pipe is suddenly stopped, shock wave produced when moving water reaches end of hose & bounces back

• Pressure surge referred to as water hammer

(Continued)

14–20

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 all valves, i.e. nozzle, hydrants slowly

14–21

Identifying Fire Streams

Fire steam is water or other agents as it leaves the nozzle toward a target

14–22

Identifying Fire Streams

• By size & 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)

14–23

Effects on Fire Streams

• Wind, gravity, velocity, & friction all affect a fire stream once it leaves the nozzle

• Nozzle design affects fire streams

• Operating pressure affects fire steams

• Condition of nozzle orifice

• Stream configuration & agents used

14–24

Fire Stream Classifications

• Low-volume stream: < 40 GPM (160 lpm)

• Handline stream: 40 – 350 GPM (160-1400 lpm)

• Master stream: > 350 GPM (1400 lpm)

Flows > 350 GPM never recommended for handlines

14–25

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)

14–26

Fire Stream Considerations

• Type of fire stream indicates specific pattern/shape of water stream

• Requirements of effective streams

• Requirements of all streams

Fire Stream Considerations

Nozzle Operating Minimum Pressures

• Fog Nozzle Handline – 100 psi (700 kPa)

• Fog Nozzle Master Stream – 100 psi (700 kPa)

• Increasing above 100 psi only increases volume but not reach

14–27

Fire Stream Considerations

Nozzle Operating Minimum Pressures

• Solid Stream Handline – 50 psi (350 kPa)

• Solid Stream Master Stream – 80 psi (560 kPa)

• Increasing above 50 or 80 psi only increases volume but not reach

14–28

Solid Stream

• Produced from fixed orifice, solid-bore nozzle

• Has ability to reach areas others might not; reach affected by several factors

• Produces little shower or spray

14–29

(Continued)

14–30

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 – to change flow rates, tips must be changed

14–31

Advantages of Solid Streams

• May maintain better interior visibility than others

• Has greater reach than other nozzles

• Operate at reduced nozzle pressures per gallon (liter) than others

• May be easier to maneuver

(Continued)

14–32

Advantages of Solid Streams

• Have greater penetration power

• Less likely to disturb thermal balance during interior structural attacks

• Produces minimal amount of steam

• Less prone to clogging with debris

(Continued)

14–33

Advantages of Solid Streams

• Produce less steam conversion than fog nozzles

• Can be used to apply compressed-air foam

14–34

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

14–35

DISCUSSION QUESTION

What type of fire situation would be ideal for a solid-stream nozzle?

14–36

Fog Stream

• Fine spray composed of tiny water droplets

• Design of most fog nozzles permits adjustment of tip to produce different stream patterns

(Continued)

14–37

Fog Stream

• Has greatest heat-absorbing capacity due to high surface area

• Desired performance of fog stream nozzles judged by amount of heat that fog stream absorbs & rate by which water is converted into steam/vapor

• Steam can extinguish some hidden fires (Continued)

14–38

Fog Stream

• Nozzles permit settings of straight stream, power cone, & full fog

• Full fog can provide personnel protection

• Nozzles should be operated at designed nozzle pressure

(Continued)

14–39

Fog Stream

• Several factors affect reach of fog stream

Wind in particular

• Interaction of these factors on fog stream results in fire stream w/ less reach than that of straight or solid stream

(Continued)

14–40

Fog Stream

• Shorter reach makes fog streams less useful for outside, defensive fire fighting operations

• Well suited for fighting interior fires

Manually Adjustable Nozzles

• Discharge rate is manually adjustable by the GPM selector ring

• Nozzle operator chooses the flow rate

• Used by FrPD

14–41

Automatic nozzles

• Discharges a wide range of flows with an effective stream depending on the pressure supplied to the nozzle

• Automatically adjust for the available flow rates

14–42

Automatic nozzles

• A minimum pressure is needed to maintain a good spray pattern

• Nozzle operator can change the flow rate by opening or closing the nozzle

• Used by FrPD

14–43

14–44

DISCUSSION QUESTION

With a manually adjustable nozzle, how should adjustments to the rate of flow be made?

14–45

Fog Stream: Nozzle Pressure

• Combination nozzles designed to operate at different pressures

• Designated operating pressure for most combination nozzles is 100 psi (700 kPa)

(Continued)

14–46

Fog Stream: Nozzle Pressure

• Nozzles w/ other operating pressures are available

75 psi & 50 psi

• Have less nozzle reaction

• Droplet size is much greater

• Fog pattern density is lower

• Stream has less velocity

14–47

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 FFs

14–48

DISCUSSION QUESTION

What type of fire situation would be ideal for a fog-stream nozzle?

14–49

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 fire

Broken Stream

• One that has been broken into coarsely divided drops

• Used in cellar, attic & partition fires

• Rotates in a circular spray pattern

14–50

14–51

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

14–52

Disadvantages of Broken Streams

• May have sufficient continuity to conduct electricity

• Stream may not reach some fires

14–53

DISCUSSION QUESTION

What are some examples of when broken streams might be used?

14–54

Handline Nozzles

• Nozzle reaction: force produced on nozzle operator as water leaves nozzle

• The water pattern produced by nozzle may affect ease of operation

Straight stream has higher nozzle reaction

Wide fog has less nozzle reaction

• Nozzles not always easy to control at/above standard operating pressures

14–55

Solid-Stream Nozzles

When water flows from nozzle, reaction equally strong in opposite direction, thus a force pushes back on person handling hoseline

(Continued)

14–56

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

14–57

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

14–58

• 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

• Also allow nozzles to be closed slowly to prevent water hammer

• Three main types

Nozzle Control Valves

(Continued)

14–59

Ball Valve

• Most common

• Provides effective control during nozzle operation w/ minimum effort

(Continued)

14–60

Ball Valve

• Ball, perforated by smooth waterway, is suspended from both sides of nozzle body & seals against seat

• Ball can be rotated up to 90 degrees by moving valve handle backward to open & forward to close

(Continued)

14–61

Ball Valve

• Nozzle will operate in any position between fully closed, fully open

• Operating nozzle w/ valve in fully open position gives maximum flow, performance

14–62

Slide Valve

Cylindrical slide valve control seats movable cylinder against shaped cone to turn off flow of water

(Continued)

14–63

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 w/o creating turbulence

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

(Continued)

14–64

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 & other valves is they also control discharge pattern of stream

14–65

Nozzle Inspections

• Swivel gasket for damage or wear;

• External damage to nozzle

• Internal damage & debris

• Ease of operation of nozzle parts

• Pistol grip (if applicable) is secured to nozzle

14–66

Ways Fire Fighting Foam Extinguishes/Prevents Fire

Class A

• Without foam, most water runs off of fuel

• Class A foam lowers surface tension of water to allow penetration of Class A fuel

• Insulates fuel from fire

Ways Fire Fighting Foam Extinguishes/Prevents Fire

Class B

• Separates fire from fuel surface

• Cools fuel surface

• Smothering: provides a blanket to exclude O2

• Suppresses flammable vapors

14–67

14–68

Terms Associated With Foam

• Foam concentrate: raw foam liquid before eduction of water & air

• Foam proportioner: device introduces foam concentrate into the water stream

• Foam solution: mixture of foam concentrate & water before air is mixed

• Finished foam: completed product after air is introduced to foam solution

14–69

How Foam is Generated

Foams in use today are the mechanical type & before use must be:

Proportioned – mixed w/ water at correct %

Aerated – mixed with air

(Continued)

14–70

How Foam is Generated

Foam is a system

Elements needed to produce firefighting foam:

(Continued)

– Foam concentrate

– Water– Air

– Mechanical agitation

14–71

How Foam is Generated

• For foam to work, concentrates must be proportioned at correct % for which it was intended

• Aeration produces foam bubbles to form effective foam blanket

14–72

Foam Expansion

• The increase in volume of foam when aerated

• Method of aerating results in varying degrees of expansion

• Best foam blankets are produced w/ aerating nozzles

Expansion Rate

Ratio of finished foam produced from foam solution after being agitated & aspirated through a foam-making appliance

• Low expansion

• Medium expansion

• High expansion

• Expansion rates are determined by foam equipment used & to some degree, the type of foam

14–73

Low Expansion

• Ratio up to 20:1

• Effective in controlling & extinguishing most Class B fires

14–74

Medium Expansion

• Ratio of 20:1 to 200:1

• Primarily used to suppress vapors from hazardous chemicals

14–75

High Expansion

• Ratio from 200:1 to 1000:1

• Used for confined space fire situations

14–76

14–77

Foam Concentrates — General Considerations

• Foam concentrates must match fuel to which it is applied

• Class A foams not designed to extinguish Class B fires

• Certain Class B foams may be used on polar solvent fires in addition to hydrocarbon liquids

14–78

Foam Concentrates — General Considerations

• Water alone is not an effective extinguishing agent for fighting Class B fires

• Do not mix different types/brands of foam concentrates in apparatus tanks

Reacts & makes foam too thick

≠

14–79

Class A Foam

• Increasingly used in structural fire fighting

• Wetting agent that reduces surface tension of water

• Allows for better foam penetration

(Continued)

14–80

Class A Foam

• Aerated Class A foam coats, insulates fuels, preventing ignition

• Uses less water

• Used at low %, i.e. .25 %, .5%, 1%

• May be used with variety of nozzles

• Can not be used on Class B fuels

Foam Concentrates used by FrPD

• Fluoroprotein foam

• Aqueous film-forming foam (AFFF)

• Alcohol-resistant film-forming foam (AR-AFFF)

• High-expansion foam

14–81

Fluoroprotein Foam

• Contain fluorochemical surfactants

• Better resistance to fuel pickup

• Faster knockdown

• Good compatibility w/ dry chemicals

• Used on hydrocarbon fuels & some oxygenated fuel additives

• Must be air aspirated to work

14–82

Aqueous Film-Forming Foam (AFFF)

• Fastest knockdown on hydrocarbon fuels

• Can be used as a premixed solution

• Can be used w/ fresh or salt water

• Compatible w/ dry chemicals

14–83

Aqueous Film-Forming Foam (AFFF)

• Hydrocarbons do not mix w/ water

Not water soluble

• Allows foam blanket to float on surface of fuels

• Film spreads ahead of blanket causing fast knockdown

• Can be used with non-aerating nozzles

14–84

Aqueous Film-Forming Foam (AFFF)

• Air/vapor-excluding film is released

• Foam blanket moves across the surface & around objects

• As blanket drains, more film is released, giving blanket ability to "self-heal“

14–85

Alcohol-Resistant Aqueous Film-Forming Foam (AR-AFFF)

• Combination of synthetic detergents, fluorochemicals, & high molecular weight polymers

• Works on polar solvents such as alcohols

• Used at different % depending on which fuel is burning

• One of the most versatile foams

14–86

Alcohol-Resistant Aqueous Film-Forming Foam (AR-AFFF)

• AR-AFFF forms a polymeric membrane between foam & fuel

• Prevents water from foam blanket from mixing w/ fuel & destroying the blanket

• Polar solvents are water soluble & mix with water

Prevent other foams from being used

14–87

Synthetic Detergent Foam (High Expansion)

• Most commonly used on Class A fires

Can be used on confined Class B fires

• Highly effective in confined spaces

• Must be made with special equipment

14–88

14–89

Proportioning

• Mixing of water w/ foam concentrate to form foam solution

• Solution must be aerated to form finished foam

• Most concentrates can be mixed with fresh/salt water

(Continued)

14–90

Proportioning

• For maximum effectiveness, foam concentrates must be proportioned at designated percentage

• Most fire fighting foams intended to be mixed w/ 94 to 99.9 % water

(Continued)

14–91

Proportioning

Foam Percentages

• Designed to be mixed with water at specific ratios

• Varies from 1% to 6% concentrate

99% to 94% water

• Depends on:

Manufacturer

Type of application

Type of fuel

14–92

Proportioning

AFFF

• Used on hydrocarbons & polar solvents

• Educted at 1, 3, & 6% for hydrocarbons

• Educted at 3 & 6% for polar solvents

14–93

(Continued)

Proportioning Methods

Eduction

• Uses venturi principle

• Water forced through a restricted opening, it increases velocity & causes a low pressure area in the eductor

• Cause foam to be picked up

14–94

(Continued)

14–95

Proportioning Methods

Batch-mixing

• Mixing foam in apparatus water tank

• Pour concentrate into tank

• Best for Class A, can be used for Class B

• Used at time of incident

• Not practical for large incidents

14–96

Proportioning Methods

Pre-mixing

• Used on twin agent/skid units

• Used in AFFF fire extinguishers

• One-time use

• Concentrate is pre-mixed in agent tank when tank/extinguisher is charged

14–97

DISCUSSION QUESTION

What proportioning methods does FrPD use?

14–98

Foam Proportioners — General Considerations

• May be portable or apparatus-mounted

• Operate by one of two basic principles

Pressure of water stream flowing through a restriction creates a venturi action

Pressurized proportioning devices inject foam concentrate into the water stream

Courtesy of Conoco/Phillips.

14–99

Portable Foam Proportioners

• In-line foam eductors

• By-pass foam eductor

• Foam nozzle eductors

Foam Proportioners

Types

• Around the pump

ARFF Vehicles

• Balanced pressure

MPAV & Industrial Pumpers

14–100

14–101

DISCUSSION QUESTION

What is the advantage of an apparatus-mounted proportioner?

14–102

Compressed-Air Foam Systems (CAFS)

• Newer structural engines are equipped w/ CAFS

• For fighting Class A fires(Continued)

14–103

Compressed-Air Foam Systems (CAFS)

• Standard centrifugal pump supplies water

• Direct-injection foam-proportioning system mixes foam solution w/ water on discharge side of pump

• Onboard air compressor adds air to mix before discharging from engine

(Continued)

14–104

Compressed-Air Foam Systems (CAFS)

• Unlike other systems, hoseline contains finished foam

• Advantages

Hoselines are lighter

Foam produced is very durable

Foam produced sticks to vertical surfaces.

• Disadvantages

Hose reaction can be significant

Requires extra training

Handline Nozzles

Solid-bore nozzles

• Used in CAFs

14–105

Handline Nozzles

Fog nozzles

• Produces low expansion foam blanket

• Produces short lasting foam blanket

• Has good reach

• Does not produce best quality foam blanket

14–106

Handline Nozzles

Air-aspirating foam nozzles/foam tubes

• Most effective appliance for low expansion foam

• Aerate the foam

• Produces highest quality foam blanket

• Has less reach than fog nozzle

14–107

Medium- and High-Expansion Foam Generating Devices

• Produces foam w/ high air content

• Medium-expansion foam Ratio of 20:1 to 200:1

• High-expansion foam mechanical blower generator Ratio of 200:1 to 1000:1

14–108

14–109

Reasons for Poor-Quality Foam/Failure to Generate Foam

• Eductor, nozzle flow ratings (GPM) do not match so foam concentrate cannot induct into fire stream

• Air leaks at fittings cause loss of suction

(Continued)

14–110

Reasons for Poor-Quality Foam/Failure to Generate Foam

• Improper cleaning of proportioning equipment causes clogged foam passages

Flush eductor after each use

• Nozzle not fully open, restricting water flow

(Continued)

14–111

Reasons for Poor-Quality Foam/Failure to Generate Foam

• Hose lay on discharge side of eductor is too long

• Hose is kinked & stops flow

• Nozzle is too far above eductor

Most eductor more than 6’ above concentrate will not function

• Mixing different types of foam concentrate in same tank results in mixture too thick to pass through eductor

(Continued)

Foam Tactics

• Need an effective size-up

• Once you begin you must have enough foam & water until fire is out

• Common types of fires: Spill fires

Three-dimensional fires

Diked fires

Tank fires

14–112

Foam Tactics

Avoid standing in foam blankets, pools of fuel or foam runoff containing fuel

• Standing or walking in foam may break the blanket

• Unburned vapors form pockets in low spots where they may ignite

14–113

Spill Fires

• Average depth of the fuel is 1" or less

• Bounded by contour of the surface on which it is lying

• Consider topography

• Fight from uphill, upwind

• Match fuel to foam

14–114

Three-Dimensional Fires

• Involve liquid fuel dripping, pouring, or running from one or more horizontal surfaces

• Fuel source must be shut off

• Extinguish fire at lowest level first

14–115

Three-Dimensional Fires

• Foam should reach fuel surface as gently as possible

• Small leaks can be confined by ground monitors or aerial monitors

• Concentrated dry chemical application combined w/ foam is required for large or pressurized leaks

Hydro chem

14–116

Diked Fires

• Areas bounded by contours of land or physical barriers that retain a depth of fuel greater than 1"

• Also known as spill fires in depth

• Require greater resources & present potential tactical challenges that may not exist in spill fires

• Requires pre-planning

14–117

Dike

Tank Fires

• Require a great amount of preplanning & resource management

• Geography is a critical element of preplan

• Tank data is essential

• Firefighting tactics determines application rates & application duration

• Extinguish dike fires first

14–118

Crude Oil

Crude oil tanks have important differences

• Water is present at the bottom of tank

• Heat wave travels through crude oil About 4 feet per hour

• Causes problems when contacting water

14–119

Crude Oil

• Frothover: Water boils under the surface, overflowing the tank

• Slopover: Pockets of water expand to steam causing oil to spill over the side

• Boilover: Water layer expands to steam, violently expelling crude oil

14–120

Boilover can cover 10X the tank diameter

Foam Application Rates

• NOTE: Perform all foam calculations BEFORE starting foam application

• If you do not have sufficient foam, do not apply what you have until you get sufficient foam Wastes the foam

14–121

Foam Application Rates

Foam calculations for spill fires per SOP 262:

Length × width = Surface area

Surface area × 0.16 = Application rate

Application rate × 15 minutes = Total flow

Total flow × 0.01 or 0.03 or 0.06 = Total concentrate needed

14–122

Foam Application Rates

Foam calculations for spill fires:

For foam to be effective at vapor control / fire extinguishment, product involved in spill or fire must have ability to pool & remain in 2-dimensional state within its containment area

14–123

Foam Application Rates

Foam calculations for tank fires per SOP 262:

D2 × 0.8 = Surface area

Surface area × 0.24 = Application rate

Application rate x 65 minutes = Total flow (foam solution)

Total flow × 0.01 or 0.03 or 0.06 = Total concentrate needed

14–124

14–125

Roll-On Foam Application Method

• Directs foam stream on ground near front edge of burning liquid spill

• Foam rolls across surface of fuel(Continued)

14–126

Roll-On Foam Application Method

• FFs continue to apply foam until spreads across entire surface of fuel & fire extinguished

• Used only on pool of liquid fuel on open ground

14–127

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)

14–128

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

14–129

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)

14–130

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

14–131

DISCUSSION QUESTION

What are some examples of when each of these techniques should be used?

14–132

Foam Hazards to Humans

• Foam concentrates pose minimal health risks to humans

• May be mildly irritating to skin, eyes

(Continued)

14–133

Foam Hazards to Humans

• Affected areas should be flushed w/ water

• Some concentrates, vapors may be harmful if ingested/inhaled

• Consult MSDS for specific information

14–134

Foam Hazards to Equipment

• Most Class A, Class B foam concentrates are mildly corrosive

• Follow proper flushing procedures to prevent damage

14–135

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)

14–136

Foam Hazards to Environment

• Environmental impact of foam concentrates varies

• Chemical properties of Class B foams & environmental impact vary on type & manufacturer

• Try not to get foam into waterways

(Continued)

14–137

Summary

• To fight fires safely & effectively, FFs must know the capabilities & limitations of all the various nozzles & extinguishing agents available

• FFs must understand the effects that wind, gravity, velocity, & friction have on a fire stream once it leaves the nozzle

• FFs must know what operating pressure nozzles require & how nozzles can be adjusted during operation

(Continued)

14–138

Summary

• FFs must know the differences between the classes of foam, how to generate foam, & how to apply foam most effectively

14–139

Skills

• Place a foam line in service — In-line eductor. (Exercise 11 Skill Sheet, FF-II-217)

• Perform Exercises 10A-F Hose handling & advancing hose