Module5 FireFightingFoamPrinciplesAndEthanol Blended

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Module 5: Fire FightingFoam Principles and

Ethanol-Blended Fuel



2

Objective

Upon the successful completion of thismodule, participants will be able todevelop foam use strategies for

controlling / fighting fires associatedwith ethanol-blended fuels.



3

Introduction

Production of ethanol large & likely tocontinue to increase

Predominate danger from tanker trucks &

rail cars carrying large amounts of ethanol, manufacturing facilities, & storage facilities

Responders need to be prepared for

large-scale emergencies & prepared withmost effective techniques & extinguishingmedia



4

Basic Foam Principles

What is foam?– “…an aggregate of air-filled bubbles formed

from aqueous solutions which is lower indensity than flammable liquids. It is used

principally to form a cohesive floating blanketon flammable and combustible liquids, andprevents or extinguishes fire by excluding airand cooling the fuel. It also prevents reignitionby suppressing formation of flammable vapors.

It has the property of adhering to surfaces,which provides a degree of exposureprotection from adjacent fires” (NFPA 11).



5


Why use foam?

–Only agent capable of suppressingvapors & providing visible proof of

security

–Foam blanket on unignited spill canprevent fire

–Suppression of vapors prevents themfrom finding ignition source



6


Why use foam?

–Can provide post-fire security byprotecting hazard until it can be

secured / removed

–Can provide protection from flammableliquids for fire & rescue personnel during

emergency operations




How foam works:

–Foam can:

Exclude oxygen from fuel vapors

Cool fuel surface with water content of foam

Prevent release of flammable vapors fromfuel surface

Emulsify fuel




How foam works:

– Foam tetrahedron:

Before being usedmust beproportioned & aerated

4 elements:

– Foam concentrate

– Water

– Air

– Aeration

Copyright 2007, TEEX/ESTI




What is foam not effective on?

–Foam is not effective on Class Celectrical fires:

Foam contains 94–97% water & waterconducts electricity

Class C fires can be extinguished usingnonconductive extinguishing agents





–Foam is not effective on 3-dimensionalfires:

Recommended to first control spill fire

Extinguish flowing fire using dry chemicalagent





–Foam is not effective on pressurizedgases:

Vapor pressure too high for foam to beeffective

Examples:

– Propane

– Butane

– Vinyl chloride

– Butadiene





–Foam is not effective on combustiblemetals:

Combustible metals usually react with water

Fires involving combustible metals requirespecialized techniques & extinguishingagents




What is foam effective on?

–Effective at suppressing vapors & extinguishing Class B fires

–2 categories of Class B products:

Hydrocarbons

Polar solvents

–Hydrocarbons–Polar solvents




Foam terminology:

–Foam concentrate

–Foam solution

–Finished foam




Types of foam:

–Protein foam

–Fluoroprotein foams

–AFFF

–FFFP

–AR foam




Foam characteristics:

–Knockdown

–Heat resistance

–Fuel tolerance

–Vapor suppression

–Alcohol tolerance



Foam Characteristics

Property Protein Fluoroprotein AFFF FFFP AR-AFFF

Knockdown Fair Good Excellent Good Excellent

HeatResistance Excellent Excellent Fair Good Good

FuelTolerance

Fair Excellent Moderate Good Good

Vapor

Suppression

Excellent Excellent Good Good Good

AlcoholTolerance

None None None None Excellent

Source: National Foam




Foam proportioning & delivery systems:

Concentration levels:

– Hydrocarbons: 3%

– Polar solvents: 6%

Foam proportioningsystems:

– Eductors:

In-line

eductors:Advantages

Property of Chauncey Naylor, reprinted with permission





Foam proportioning& deliverysystems:

– Foam proportioningsystems:

Eductors:

– Bypass eductors

– Common eductor

failures





20


Foam proportioning & delivery systems:

– Foam proportioning systems:

Foam nozzles:

– Foam proportioning nozzles:

Advantages




21


Foam proportioning& deliverysystems:

– Foam proportioningsystems:

Air aspiratingnozzles

Non-air aspirating

nozzles




22


Application techniques:

–Never plunge foam directly into the fuel

–Bounce-off:

Effective if there is an object in / behind spillarea

–Bank-in:

Particularly effective with non-air aspiratingfog nozzles



23


Application techniques:

–Rain-down:

Nozzle elevated & foam allowed to fall over

spill as gently as possible



24

Foam and Ethanol andEthanol-Fuel Blends

Foams not developed for applicationon alcohol- / ethanol-blended fuels:

– Ineffective on fuels containing alcohols /

ethanol: Alcohol / Ethanol attacks & absorbs foam

solution



25


AR foams:

–Forms tough membrane between foamblanket & alcohol-type fuel

–Crucial to use in combatingethanol-blended fuel fires

–Apply gently to surface of alcohol- /

ethanol-blended fuels



26


AR foams:

–Use Type II application techniques:

Apply indirectly to fire

–Type III application:

Effective only when deflected off surfaces

Best option may be to protect surroundingexposures



27


Require higher flow rate of foam toextinguish fires:

–AFFF-type: 1 gpm foam / 10 ft2 burning

surface on hydrocarbon-type fuel

–Ethanol-blended fuels: 2 gpm foam / 10ft2 of AR type foam



28

Foam Recommendations forFire Departments

Consider converting to AR foamconcentrates

Develop means of having cache of AR foam readily available



29


AR foams effective on both alcohol & hydrocarbon fires:

–Some have quicker knockdown abilities

& longer foam retention times thanprotein-based hydrocarbon foams

–Thermal imaging camera recommended



30


Copyright ERG



31


AR foams effective on both alcohol & hydrocarbon fires:

–Uncertain if fire is

alcohol- / ethanol-blended: Consider doubling application rate

–Foam of choice



Summary

AR foam best choice for incidents

AR foam recommended choice for allfuel fires involving gasoline- /

ethanol-blended fuels AR foam performs on hydrocarbon

fires as well:

–Preferred choice from responsestandpoint if nature of burning fuel isunclear

Module5 FireFightingFoamPrinciplesAndEthanol Blended

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