r AD-A141 928 EVALUATION OF AQUEOUS FILM FORMING FOAMS

(AFFF) ON DECK IFIRES(U) COAST GUARD RESEARCH AND DEVELOPMENT CENTERGROONCT D EBEENE OCT 83 CGRDC-583 USCG-D-184

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HE-PORT NO: CG-D-11-84 (j.. I

EVALUATION OF AQUEOUS FILM FORMING FOAMS (AFFF)ON DECK FIRES

DAVID E. BEENE, JR.

00 U.S. Coast Guard Research and Development Center

C%4 Avery Point Groton, Connecticut 06340

Ir.

October 1983

Final Report D T IC~ ELECTE

JUN 8 1984

Document is avadable to the U.S. Public through the - BNational Technical Information Smovce B

Springfield. Virginia 2161

PREPARED FOR

U. S. DEPARTMENT OF TRANSPORTATIONUNITED STATES COAST GUARD

OFFICE OF RESEARCH AND DEVELOPMENTWASHINGTON D.C. 20593

84 06 Olt- 004

This document is disseminated under the sponsorship of theDepartment of Transportation in the interest of informationexchange. The United States Government assumes no liabilitytor its contents or use thereof.

The United States Government does not endorse products ormanufacturers. Trade or manufacturers' names appear hereinsoley because they are considered essential to the object ofthis report.

The contents of this report reflect the views of the CoastGuard Research and Development Center, which is responsiblefor the facts and accuracy of data presented;- This reportdoes not constitute a standard , specification, or regulation.

SAMUEL F. POWEL, Ill

Technical DirectorU.S. Coast Guard Research and Development CenterAvery Point, Groton, Connecticut 06340

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Technical Report Documentation Page

1. ROg*" NO. 2. Government Accession No. 3. Recsilent's Catalog No.

CG-D-11-84 V A A - _ _ _ _ _ _

4. Title and SuOttne 5. Recort Date

Evaluation of Aqueous Film Forming Foams (AFFF) On October 1983Deck Fires S. Pirtorminq Organization Code

a. Poirtorming Organization Regort NO.T. Aulreor(s)David E. Beene, Jr. CGR&DC 5/83

9. Performing Organization Name and Addresa 10. Work Unit No. CTRAIS)

U.S. Coast Guard Research and Development CenterAvery Point 11. Contract or Grant No.Groton, Connecticut 06340

13. Tyoe ot Reor and Period Covered12. Sonsoring Agency Name and AddressDepartment of Transportation Final ReportU.S. Coast GuardOffice of Research and Development 14. Soonsoring Agency COoWashington, D.C. 20593

15. Suaolenmentary Notes

Aqueous film forming foam (AFFF) concentrates were tested in full-scale deck fires at the U.S. CoastGuard Fire and Safety Test Detachment in Mobile, Alabama. The testing was conducted on the after tank deck ofthe Tank Vessel A.E. WATTS. It simulated a spill fire with obstructions on the after flight deck of a CoastGuard cutter. The spill fires were conducted..using marine diesel as the test fuel.

The purpose of the testing was to evaluate the firefighting effectiveness of different AFFFconcentrates and to determine whether 1% or 3% AFFF concentrates could be used to replace the 6% MilitarySpecification AFFF concentrate used on board Coast Guard cutters. This replacement could reduce the weight andspace required for AFFF storage or increase the overall time of firefighting effectiveness. The AFFF's testedwere 3% and 6% AFFF concentrates meeting Military Specification MIL-F-24385, two commercial 37 AFFFconcentrates, two polar solvent resistant 3% AFFF concentrates, and a 1% commercial AFFF concentrate. %Asecondary objective was to evaluate the firefighting effectiveness of the four nozzles used aboard Coast Guardcutters when using AFFF.

The tests demonstrated that the 3% AFFF concentrates were as effective as the 6% MilitarySpecification AFFF concentrate in controlling and extinguishing deck fires, The test results also indicatedthat the 3% AFFF concentrates compared equally to the 6% Military Specification AFFF concentrate-in sealingaround hot metal surfaces and in burnback resistance. The 1% AFFF concentrate had control and extinguishmenttimes comparable to those of the 6% AFFF Military Specification concentrate, but it was the least acceptableAFFF because of its poor burnback resistance. These test results are based on accurate AFFF proportioning. Ifthe accuracy of the proportioners used is questionable, then sensivity testing should be conducted.

The Coast Guard All Purpose (CGAP) nozzle and the Twin Agent Unit (TAU) nozzle had the longest controland extinguishment times while the Mechanical Foam Nozzle (MFN) and the Select-O-Flow (SFL) nozzle had theshortest control and extinguishment times. The SFL nozzle with its multiple control modes was the mostversatile and overall effective nozzle. I

17. K*e erd 18. OL ieoutlon SatementAFFFDeck Fires Document is available to the U.S. publicAqueous Film Foming Foam through the National Technical Information

Service, Springfield, VA 22161

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Acknowledgements

The U.S. Coast Guard appreciates the assistance of National Foam System,Inc., Ansul Fire Protection, 3M-Fire Protection Systems, Elkhart BrassManufacturing Company, Inc., and Akron Brass Company in providing materialsand equipment used during the testing. The willing cooperation andparticipation of these companies led to the successful accomplishment of thistest program.

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TABLE OF CONTENTS

1.0OINTRODUCTION. .. ... ..... ...... ..... ...... 1

2.0OOBJECTIVES .. .. .... ...... ..... ............

3.0BACKGROUND .. .. .... ...... ..... ........... 2

3.1 Aqueous Film Forming Foam (AFFF) .. .. ... ......... 23.2 Extinguishment by AFFF .. .. .. ............. 23.3 Codes and Specifications for Conmmercial Veisels ; 43.4 AFFF On Coast Guard Cutters .. .. ..... .......... 53.5 Nozzles Used on Coast Guard Cutters .. .. ..... ..... 5

4.0OAPPROACH .. .. .... ...... ..... ...... ..... 7

4.1 Fire Scenario .. .. ..... ..... ...... ..... 74.2 Limitations. .. ... ..... ...... ......... 7

5.0OPROCEDURES. .. ... ..... ...... ..... ....... 11

5.1 Test Pen and Fuel .. .. ..... ...... ........ 115.2 Fire Tests. .. .. .... ...... ..... ....... 115.3 Nozzle Operation .. .. .. ...... ..... ....... 115.4 Foam Quality .. .. .. ...... ..... ......... 145.5 Application Rate.g... ...... ..... ....... 145.6 Foam Proportioning. ...... ..... ......... 165.7 Control/Extinguishment. .. .. .... ..... ...... 165.8 Sealability Tests .. ...... ..... ......... 165.9 Burnback Tests .. . .. .... .. ............ 175.10 Instrumentation. .. ... ..... ...... ....... 17

6.0ORESULTS AND DISCUSSION .. ... .... ..... ......... 17

6.1 Environmental Factors .. .. ..... ..... ....... 196.2 Pretest Fires. .... .. .. .............. 196.3 Foam Quality......................20

6.3.1 AFFF Concentrates.................226.3.2 Nozzles .. .. .. .......... ........ 23

6.4 Control/Extinguishment Times .. .. .. ...... ..... 246.5 Sealability .. .. ...... .... ...... ..... 286.6 Burnback Resistance .. .. .... ..... ........ 28

7.0 SUW4ARY/CONCLUSIONS .. .. .. ...... ..... ........ 32

7.1 AFFF Concentrates .. .. ..... ..... ......... 327.2 Nozzles .. .. ........ .. .............. 33

REFERENCES. .. ... .... ...... .............. 35

v

TABLE OF CONTENTS (con't)

APPENDIX A Suggested Test Methods and Calculations. .. .. ...... A-1

APPENDIX B Instrumentation. .. .. ..... . .... ........ B-1

APPENDIX C AFFr Fire Test Data. .. .. ... ....... ..... C-1

LIST OF ILLUSTRATIONS

Figure pg

1 How AFFF Works ........ ....................... 3

2 Nozzles Used on Coast Guard Cutters ..... ............ 6

3 Test Area on Tank Vessel A.E. WATTS ..... ............ 8

4 Diagram of Test Variables ....... ................. 9

5 Test Pen ......... .......................... 12

6 Fire Protection After Extinguishment ................ 18

7 Nozzle Control Modes Used ... ................. .... 26

8 Pipe Temperatures in Sealability Tests ............... 29

9 AFFF Burnback Resistance ....... .................. 30

10 The Effect of Nozzle Design on Burnback Resistance ..... ... 31

LIST OF TABLiS

Table Page

1 Test Schedule ........ ....................... 10

2 Comparison of Fuel Characteristics ..... ............. 13

3 Control Modes Used During Testing ..... ............. 15

4 Foam Quality Results ....... .................... 21

5 Control/Extinguishment Times .................... ... 25

vii

1.0 INTRODUCTION

Aqueous film forming foam (AFFF) has gained widespread recognition in thefire service community as being an effective fire fighting foam for use onliquid spill fires and petroleum storage tank fires. This recognition isnoted by the fact that AFFF is used by the Navy for shipboard firefighting andby the U.S. Air Force for crash rescue vehicles at its airfields. Firefighting brigades of large oil refineries are also adopting AFFF for use. Dueto its effectiveness and widespread use, the National Fire ProtectionAssociation has developed a National Fire Code of recommended practices forthe use of AFFF.

Six percent AFFF meeting the requirements of MIL-F-24385 Type 6 is theonly firefighting foam concentrate authorized for use on Coast Guard cuttersand boats. The specification for 6% concentrate requires that 6% of eachgallon of AFFF solution mixed is AFFF concentrate. Currently 3% and 1% AFFFconcentrates are also commercially available. The 3% AFFF would require that3% of each gallon of AFFF solution mixed is AFFF concentrate whereas a 1% AFFconcentrate would require that 1% of each gallon of AFFF solution mixed isAFFF concentrate.

2.0 OBJECTIVES

The purpose of this testing was to evaluate the firefightingeffectiveness of different AFFF concentrates to determine whether 1% or 3%AFFF concentrates could be used to replace the 6% Military Specification AFFFconcentrate used on board Coast Guard cutters.1 Such a replacement couldreduce the weight and space required for AFFF storage aboard Coast Guardcutters by as much as 50% for 3% AFFF and 83% for 1% AFFF. The foams testedwere 3% and 6% AFFF concentrates meeting Military Specification MIL-F-24385,two commercial 3% AFFF concentrates, two polar solvent resistant 3% AFFFconcentrates, and a 1% commercial AFFF concentrate. All the foams tested areadvertised for use on hydrocarbon (Class B) fires. TWO of the foams are alsodesigned for use on polar solvent (e.g. alcohol) type fires. The specificobjectives were:

(1) To evaluate the firefighting effectiveness of different AFFFconcentrates on deck fires.

(2) To evaluate the AFFF's ability to resist breakdown around hot metalobstructions.

(3) To evaluate the AFFF's foam blanket stability over an extendedperiod of time.

(4) To evaluate and compare the above mentioned characteristics forcommercial AFFF and AFFF meeting Military Specification MIL-F-24385C.

A secondary objective was to evaluate the firefighting effectiveness ofnozzles on Coast Guard cutters while using AFFF. The AFFF used in thistesting was to be either 6% AFFF or whichever concentrate proved equivalent toit.

, , - . . . . .. . . i - - , - -

The specific objectives of the nozzles evaluation were:

(1) To evaluate and compare the firefighting effectiveness of nozzlesused on Coast Guard cutters when using AFFF.

(2) To evaluate and compare the foam characteristics produced by thenozzles.

3.0 BACKGROUND

3.1 Aqueous Film Forming Foam (AFFF)

AFFF is a combination of fluorocarbon surfactants and syntheticfoaming agents which spread out across the surface of a liquid which is onfire to provide a rapid "knock-down" of the flames.2 The new dimension inthis foam is its aqueous film. This film is a thin layer of foam solutionthat rapidly spreads across the hydrocarbon fuel while extinguishing theflames as it spreads (figure 1). The aqueous film is produced by the actionof the fluorocarbon surfactant reducing the surface tension of the foamsolution to a point where the solution can actually be supported by thesurface tension of the hydrocarbon fuel. The effectiveness and durability ofthe aqueous film is directly influenced by the surface tension of thehydrocarbon fuel. For example, AFFF is more effective on fuels having highersurface tension such as diesel oil, jet fuels and kerosene. It is lesseffective on fuels having lower surface tension such as hexane and high octanegasolines. It is the rapid drainage of the foam solution from the foam bubblewhich produces optimum filming for rapid fire extinguishment. There isconcern that this rapid drainage results in short-term sealability and limitedburnback resistance.

AFFF's have also been developed to combat polar solvent (watersoluble) flammable liquids. This type of AFFF forms a cohesive polymeric filmon the fuel surface of the polar solvent.3 This polymeric layer protectsthe foam and its aqueous film from the chemical and physical breakdown actionof the polar solvent. If the protective layer of polymeric film is broken byagitation, more polymeric film is produced to fill the break. When polarsolvent resistant AFFF's are used on hydrocarbon fires, they extinguish thefire in the same manner as normal AFFF. Although polar solvent resistantfoams may be used on hydrocarbon fires, historically they have not been aseffective as normal protein or fluoroprotein foams. The new polar solventresistant AFFF's have been specially formulated to be equally effective onhydrocarbon fires.

3.2 Extinguishment by AFFF

AFFF extinguishes a fire in three ways:

(1) It smothers the fire by using its aqueous film to prevent airfrom mixing with the flammable vapors.

.. .. .... . .... .... . _ _

HYDROCARBON FLAMMABLE FLAMES

... ....

(2) It suppresses flammable vapors ?d prevents their release.

(3) It cooT ILe fuel and adjacent metal surfaces.

The aqueous film, which produces the rapid "knockdown" of the fire,appears to be produced at the sacrifice of the foam blanket's cooling abilityand its burnback resistance. This occurs as the aqueous film drains from thefoam to knockdown the flames, for as the film is disrupted it regeneratesitself at the foam's expense.

3.3 Codes and Specifications for Commercial Vessels

It has been the position of the Coast Guard that the rapid fireknockdown ability of AFFF is indicative of only a portion of fire fightingrequirements. Title 46 Code of Federal Regulation, Part 34.05, requires theinstallation of deck foam systems aboard tankers, and that all such systemsare Coast Guard approved. Coast Guard approval requires that the foamsuccessfully meet the fire test requirements of Federal SpecificationO-F-555C. These requirements address the firefighting effectiveness,sealability, and burnback resistance.

0-F-555C is a small-scale 100 square feet (9.3 sq m) fire testconsidered to be representative of some of the conditions encountered infull-scale tanker fires. It simulates:

1. The ability of the foam to resist breakdown when propelled from afoam monitor through a curtain of flame on to a metal backboard, theil flowingdown the hot metal and covering the surface of the ourning fuel. This is incontrast to many industrial applications where the foam is spread gently fromtank-side nozzles positioned at the liquid level height, resulting in aminimum exposure of the foam to flames and hot steel; or where loams areinjected into the bottom of a tank and then float up through the fuel to itssurface.

2. The ability of the foam blanket to resist breakdown over a periodof time, thus preventing re-exposure of the fuel to sources of ignition. Thisis representative of tanker fire conditions where given the certain timeneeded for fire detection, system activation and response, a large segment ofthe ship may become involved in flames. If the fire is progressively foughtfrom aft to forward from foam station to foam station, the length of timerequired for the foam blanket to remain effective in covering and sealing thefuel is considered to be a minimum of 20 minutes.

3. The ability of the foam to contain reignited openings in the foamblanket, and thus prevent the entire hazard area from reflashing. This isdetermined by opening a measured area in the foam blanket, igniting it, anddetermining the breakdown rate of the surrounding foam blanket.

At the time Federal Specification 0-F-555C was developed as asmall-scale fire test and correlated to full-scale tanker-type fires, the onlycommercially available foam was 6% protein foam concentrate. Later, 30protein foam concentrate, flouroprotein synthetic foams, and AFFF weredeveloped. A modified Coast Guard version of 0-F-555C was not adopted sinceit was the Coast Guard's position that the hazard conditions addressed byO-F-555C remained unchanged and any newer foams should address these same

J4

• . . .. . . . . . . . . .

hazardous conditions.

3.4 AFFF On Coast Guard Cutters

Aqueous film forming foam plays an important role in the overall fireprotection on Coast Guard cutters.

a. Engine room protection is proved by a Twin Agent Unit(TAU). This unit provides AFFF solution and PKP (dry powder) through twinhoses and a dual nozzle setup such that an operator can apply either foam andor dry chemical as needed.

b. Helicopter flight deck protection is provided from two AFFFhose stations with SFL type variable pattern foam nozzles. The foam solutionfor these stations is usually provided from an installed proportioner system.

c. All cutters carry Type 6 AFFF in pails [5 gallons (18.9liters) each], portable inline eductor type proportioners, and mechanical foamnozzles for protection of machinery spaces, and flight decks.

d. The only foam concentrate currently authorized by theCommandant for use aboard Coast Guard cutters and boats is MilitarySpecification MIL-F-24385C Type 6. When properly proportioned, 6 parts ofAFFF concentrate plus 94 parts water equal 100 parts of unexpanded foamsolution.

3.5 Nozzles Used on Coast Guard Cutters

Only four nozzles are authorized for use on Coast Guard cutters.These authorized nozzles include the 1 1/2-inch Coast Guard All Purpose (CGAP)nozzle, the 1 1/2-inch Mechanical Foam Nozzle (MFN), the I 1/2-inchSelect-O-Flow fSFL) nozzle, and the Twin Agent Unit (TAU) nozzle (figure 2).Each of these nozzles can use an AFFF solution to attack a fire, but basicallyonly two of the nozzles are designed as foam application devices. Thefirefighting effectiveness thus varies because of different nozzle design anddepending on how and where the nozzle is being used. For example, the TwinAgent Unit nozzle is an aerating type nozzle with the aeration being externalto the nozzle as the solution passes through an expanded metal screen. It isdesigned for close-up fire situations such as in a bilge or engine fire. It,therefore, provides a wide fog pattern but does not have a great reach againsta deck fire. The 1 1/2-inch SFL nozzle because of its adjustable fog patternand straight stream patterns would be capable of both closeup and long-rangetype fire fighting. The spray pattern generated and the teeth in the face ofthe nozzle aerates the foam to some degree thereby increasing its overalleffectiveness. The I 1/2-inch Mechanical Foam Nozzle is an aerating typenozzle with eration occurring inside the nozzle. It has good rangecapabilities but has no adjustment mechanism for a fog pattern for closefirefighting situations. In this type situation its foam discharge would haveto be banked off a wall or obstruction. Close-up firefighting could behazardous to its operator. The 1 1/2-inch Coast Guard All Purpose nozzle hasboth a straight stream and fog pattern setting but its design fails to aeratethe AFFF sufficiently to create a thick frothy foam blanket.

5

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COAST GUARD ALL PURPOSE TWIN AGENT UNIT NOZZLENOZZLE

SF1 NOZZLE MECHANICAL FOAM NOZZLE

FIGURE 2NOZZLES USED ON COAST GUARD CUTTERS

6

4.0 APPROACH

All testing was conducted at the U.S. Coast Guard Fire and Safety TestDetachment in Mobile, Alabama. Full-scale fire tests, burnback tests,sealability tests, and foam quality tests were conducted on the after tankdeck of the Tank Vessel A. E. WATTS at Little Sand Island (figure 3). Apremix foam tank and a foam pump were used in all the full-scale firetesting. The vessel was fitted with the necessary fire containment barriers,fire mains, and instrumentation. Three pretest fires were conducted todetermine the application rate which would provide optimum control andextinguishing times for comparison and evaluation of the AFFF concentrates andof the different nozzles. All final nozzle adjustments were worked out in thepretest fires. The different AFFF's were evaluated with an SFL nozzle on anoscillating mount while the four nozzle described in Section 3.5 wereevaluated under manual operating conditions.

The primary independent variables for the AFFF evaluation were the firetype, the extinguishing mode, the AFFF concentrates and the different nozzles(Figure 4). Test parameters held constant were: number of tests per set-up,preburn time, fuel type, ignition source, and fire fighting technique. Theprincipal dependent variables measured were control times, extinguishingtimes, sealability and burnback resistance.

4.1 Fire Scenario

The test series was intended to simulate a fire surrounding adisabled helicopter on the aft deck of a Coast Guard cutter. A worst casefire scenario describing this situation is as follows: During the finalrefueling of a helicopter on the deck of a Coast Guard cutter, the landingcarriage collapses and the fuel tank ruptures spilling fuel onto the cutter'sdeck. The fuel then ignites by an ignition source created by the helicopter'scollapse. The fire spreads rapidly across the deck and is fueled by the hoseline which was refueling the helicopter. A spill fire with obstructions hasoccurred. Wind conditions and a delay in attacking the fire add to thedifficulty of its extinguishment.

4.2 Limitations

An inherent problem in any full-scale testing is the difficulty induplicating all the variables which affect the results. This in turn leads todifficulty in the repeatability of test results and a potential loss of testcredibility. In this test series, each test was conducted three times toprovide confidence and credibility in the results.

The test schedule was designed to provide consistent results in thepresence of experimental testing which often produces bias or random errors.Blocking and randomization were used to reduce or eliminate bias errorsattributed to different AFFF concentrates, nozzles, and environmentalfactors. The test schedule in Table 1 employed the above techniques for thetesting sequence of the AFFF concentrates and the nozzles.

The use of the oscillating nozzle reduced any bias error associatedwith different operators. Additionally, it insured that each of the foamconcentrates was applied in the same manner and that the same quantity of foam

7

ViVEAMER IAER

TESTJTE SUPPAINLYC

TANK~ TOM AN

TEST AE PREMIAN FESSE TAEWTT

8

TEST VARIABLES

- INDEPENDENT DEPENDENTINPNDT

-Extmpuishment Time

-Sealablity-Burnback

F1RTP M7AREYSPECFATN

31 & 6%SILITARYECIFICATION AIRE

MOFGUE 4OD

TWO % CMMER AGRAM OF TESTIVRIABLE

MII"

,ABLE 1TEST SCHEDULE

OSCILLATING OPERATION MANUAL OPERATION

Pretest#/Nozzle-AFFF Test*/Nozzl e-AFFF Test#/Nozzl e-AFFF

1-A 1-A 22-H2-A 2-B 23-I3-A 3-C 24-J

4-C 25-K5-A 26-H6-8 27-17-8 28-J8-C 29-K9-A 30-H10-0 31-1ll-E 32-J12-F 33-K13-F14-015-E16-E17-F18-019-G20-G21-G

Legend: (Nozzle, AFFF Concentrate, Foam Manufacturer)

A - SFL 61 Military Specification (Ansulite) Ansul Fire ProtectionB - SFL 3% Comercial (Aer-O-Water) National Foam System, Inc.C - SFL 31 Military Specification (Ansulite) Ansul Fire Protection0 - SFL 31 Polar Solvent Resistant (National Universal) Hationa) Foam System, Inc.E - SR. 3% Commercial (Light Water) 3M Fire ProtectionF - SFL 1 Commercial (Ansulite) Ansul Fire ProtectionG - SFL 31 Polar Solvent Resistant (Alcohol Type Concentrate) 3M Fire ProtectionH - TAU 31 Military Specification (Ansulite) Ansul Fire ProtectionI - CGAP 31 Military Specification (Ansulite) Ansul Fire ProtectionJ - SF1. 3% Military Specification (Ansulite) Ansul Fire ProtectionK - MFN 31 Military Specification (Ansulite) Ansul Fire Protection

was delivered inside the test pen. The nozzle pattern was preadjusted toinsure no waste. Longer control and extinguishment times might be expectedbecause of the passive extinguishment method of the oscillating nozzle, butthe most valid comparison of foam effectiveness was made with a reproduciblefi ref ighti ng technique.

Only one operator was used in the nozzle testing in order toeliminate different extinguishing techniques or methods attributed to

* different human operators. Randomization of the different nozzles reduced any* additive learning effects by not allowing the same nozzle to be used

consecutively. The active extinguishing method of the operator provided arealistic evaluation of the different nozzle's effectiveness during manualoperation.

5.0 PROCEDURES

The testing was conducted in a test pen fitted with the instrumentationnecessary to record temperatures, wind speed, wind direction, test time, andheat fluxes. Color videotapes and 35nin cameras were used to document eachtest.

5.1 Test Pen And Fuel

A series of steel coamings on the after main deck of the Tank VesselA.E. WATTS was used as the test pen. The test pen contained approximately1000 square feet (92.9 sq m) and was 33 feet (10.1m) long by 30 feet (9.1m)wide (figure 5). Several obstructions were included inside the test pen.Normally, the fire situation during the crash of a helicopter refueling on aCoast Guard cutter would involve JP5. Its high cost and the difficulty ofsecuring and transporting it to the test site necessitated the use of asubstitute fuel. Marine diesel was used as the test fuel since it is lessexpensive, more available, and has similar flanmmability characteristics5

* (Table 2).

The test pen was filled with water to a depth of two to four inches(5.1 to 10.2 cm) below the top of the coaming. The test fuel was floated onthe water's surface, its depth ranging from one to two inches (2.5 to 5.0cm). The test fuel covered the entire test pen except for an existing tanktop and obstructions. Floating the fuel on the water surface served toprotect the deck from the intense heat of the flames. Sections of the deckaround the test pen required water applied to it during each test to keep thedeck plates from buckling.

Since the more volatile fuel elements burned off and the fuel wasdiluted by the continued application of foam during each test, fresh fuel wasadded before each test to reproduce flame severity. Ten gallons of mineralspirits were spread over the fuel prior to each test to aid in ignition. Twofirefighters used special propane torches to ignite the mineral spirits alongthree sides of the test pen. Flames normally engulfed the entire test pen intwo and a half minutes. A one minute full involvement preburn was given foreach test. Foam discharge was initiated at the foam pump at the conclusion ofthe one-minute preburn. At the conclusion of each test the water level in thetest pen was raised so that the remaining AFFF could be skinmmed off the fuelsurface into an adjacent holding pen.

6 G, STARBOARD

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HATCH

5' VALVE--

Ar' 10 VALVE

BURNBACK

t AFFF COVERAGE

CATWALK =,-SUPPORTS

PORT?

Oscillating Nozzle Location

FIGURE 5

TEST PEN

TABLE 2COMPARISON OF FUEL CHARACTERISTICS

Marine Diesel JP-5Flash Point 125°F (51.70C) 140OF (600C)Flammable Limits in Air 1.3% - 6.0% 0.6% - 4.6%Ignition Temperature 490-545°F (254.4-2850C) 475OF (2460C)

NFPA Fire HazardClassification Red, 2 Red, 2Availability Delivered to test ship Hire a truck

by barge driver forpickup anddelivery fromout of state(three trips).Move LCM withstorage tankback and forthto test ships(three trips)

Price $1.05/gal $l.25/gal

13

5.2 Fire rests

A total of 36 fire tests were conducted, including three pretestfires to insure that the oscillating nozzle and the foam pump were functioningproperly. Twenty-one fire tests were conducted to evaluate the seven AFFFconcentrates while 12 fire tests were conducted to investigate theeffectiveness of the four nozzles. Each of the seven AFFF concentrates andeach of the nozzles was used in three separate fire tests.

5.3 Nozzle Operation

A non-aerating type nozzle on an oscillating base was used in the 21fire tests fires to evaluate the different AFFF concentrates (Table 3). TheSFL nozzle was used for the 21 tests. This nozzle is normally located on aCoast Guard cutter flight deck and would be the primary nozzle used in anafter deck spill fire. The oscillating base was preadjusted to a fixed angleof elevation and arc of oscillation. Identical oscillation of the SFL nozzlewas used in each test. This increased the repeatability of test results andserved to eliminate errors associated with different attack patternsassociated to human operators. The non-aerating nozzle was operated at a flowrate of 95 gallons per minute (360 1pm) and a nozzle pressure of 100 psi (685kN/m2) for the AFFF evaluation. This flow rate was determined from thethree pretest fires.

The 12 nozzle fire tests were extinguished by a firefighter in aproximity suit. A different nozzle was used each time to insure that theoperator's learning curve developed equally for each nozzle (Table 3). Thefour nozzles tested are listed in section 3.5. The nozzles were operated atflow rates from 60 to 45 gallons per minute (227 1pm to 170 1pm) and at anoperating pressure of 100 psi (685 kN/m2) Variable flow rates were usedbecause a single rate was not commnon to each nozzle. This did permit acomparison of similar flow rates. The aggressive attack procedure of theoperator made up for the difference in flow rates between the AFFF concentratetesting and the nozzle testing.

5.4 Foam Quality

For each fire test a foam sample was collected for qualitativetesting. The samples were collected in accordance with National FireProtection Association Standard No. (NFPA) 4126, Appendix A-220. Foamexpansion determination was determined according to NFPA 412, page 412-20,Appendix A-230, and foam drainage times were determined according to NFPA 412,Appendix A-240. The above methods are described in Appendix A.

5.5 Application Rate

A single application rate of 0.1 gallons per minute per square foot(4.1 liters per minute per square meter (lpmin/sqm)) was used with theoscillating nozzle to conduct the AFFF concentrate testing. A smallerapplication rate of 0.04 gallons per minute per square foot (1.6 lpmin/sqm)was tested with the oscillating nozzle on two pretest fires but the fires wereneither controlled nor extinguished. A third pretest fire was successfullyextinguished in 3 minutes and 20 seconds using the 0.1 gallons per minute persquare foot (4.1 lpmin/sqm) rate, therefore it was used as the test rate.Previous small scale testing indicates that fires can be extinguished manuallyby smaller application rates when using an aggressive attack mode. The largertest application rate, however, provided a margin of safety to account for the

14

application rate selected is also used in Coast Guard approved AFFF systemsfor protecting helicopter decks on mobile offshore drilling rigs and isrecommended by the National Fire Codes for the extinguishment of hydrocarbonspill fires.

Application rates used in testing the effectiveness of the fournozzles mentioned varied from .045 to 0.06 gallons per minute per square foot(1.8 to 2.4 Ipmin/sqm). These rates are considered to be slightly above theminimum rate considered necessary for flame extinguishment.

TABLE 3CONTROL MODES USED DURING TESTING

Control Number Nozzle AFFF Concentrate

Mode of Tests

Oscillating 3 SFL 1% Commercial (Ansulite)

Oscillating 3 SFL 3% Military SpecificationMIL-F-24385C (Ansul ite)

Oscillating 3 SFL 6% Military Specification

PIIL-F-24385C (Ansul ite)

Oscillating 3 SFL 3% Commercial (Light Water)

Oscillating 3 SFL 3% Commercial(Aer-O-Water)

Oscillating 3 SFL 3% Polar Solvent Resistant(Alcohol Type Concentrate)

Oscillating 3 SFL 3% Polar Solvent Resistant(National Universal)

Manual 3 1 1/2" SFL 3% Military SpecificationMIL-F-24385C (Ansul ite)

Manual 3 1 1/2" CG 3% Military SpecificationAll Purpose MIL-F-24385C (Ansulite)Nozzle

Manual 3 1 1/2" TAU 3% Military SpecificationMIL-F-24385C (Ansul ite)

Manual 3 1 1/2" MFN 3% Military SpecificationMIL-F-24385C (Ansul ite)

15

... . ..L . .

5.6 Foam Proportioning

A 500 gallon (1892.5 1) premix tank and pump were used to provide thefoam solution used in each test. The foam proportioning concentration waschecked by two methods. One method used is listed in NFPA 412, AppendixA-250. The second method is used by the Navy and also involves the use of arefractometer. The formula for this method is:

PC = RN - RSRC - RS x 100

where: proportioning concentration = PCrefractive index of foam solution at nozzle = RNrefractive index of saltwater = RSrefractive index of foam concentrate = RC

Before each test the tank was filled with seawater and apredetermined quantity of foam concentrate to form the desired foam solutionconcentration. A motor driven propeller was located inside the tank tothoroughly mix the foam concentrate and seawater. After each test, the tankwas drained and flushed before the next AFFF soluton was mixed.

5.7 Control/Extinguishment

Control time was subjectively determined as the time from AFFFapplication until the point where the fire would be of no further danger tothe vessel if eventual extinguishment were made. This was considered to be apoint where flames cover no more than ten percent of the test pen area.Extinguishment time was the time from AFFF application until all visibleflames in the test pen coamings was out. Control times provide moreconsistant results than extinguishment times in evaluating fire fightingeffectiveness because extinguishment times constantly vary due to flickeringfires which continue to burn around obstructions or in and around the cornersand edges of a test pen. 7 , 8

5.8 Sealability Tests

Sealability is a measure of a foam's ability to maintain its sealaround surfaces when subjected to high temperatures. Failure occurs if thefoam retracts from the high temperature sources and the fuel ignites. Aftereach test fire had been extinguished, a heated pipe apparatus and two propanetorches were used to determine the sealability of the AFFF being tested. Onepropane torch was placed inside a section of pipe which was half-submerged inthe test pen water, fuel, and foam (figure 5). The second propane torch waspositioned approximately 6 inches (15.2 cm) above the surface of the heatedpipe which corresponded to about 7 inches (17.7 cm) above the surface of thefuel. Both propane torches were energized one minute after the test fire was

16

LI

fully extinguished. Flames were applied for 15 minutes. The purpose was todetermine if the foam would break away from the hot metal and if fuel vapor inthis area would subsequently ignite.

5.9 Burnback Tests

The burnback tests were designed to measure hie resistance of thefoam blanket on the fuel to burnback after the test fires had beenextinguished. One minute after each test fire was extinguished a one-foot(0.3 m) diameter circular open pan was placed inside the designated burnbackarea of the test pen. It was positioned on a line near the center of theforward coaming and three feet (0.9 m) inside the pen. This area was markedoff in one-foot (0.3 m) spacings by steel rods extending one foot (0.3 m) highabove the fuel and foam (Figure 5). These rods provide a reference forestimating the burnback area. The foam was cleaned out of the one-foot(0.3 m) pan and 14 ounces (0.4 1) of mineral spirits were added inside the panto assist the ignition of the fuel. The mineral spirits were ignited by apropane torch two minutes after the entire test pen had been extinguished.The fuel inside the one-foot (0.3 m) pan was allowed to burn for one minuteand then the pan was removed (Figure 6). The flames were allowed to continuefor 15 minutes or until they consumed their way outside the designed testarea. During this time, the rate and time of the enlargement of the fire wererecorded.

5.10 Instrumentation

The instrumentation and procedure used to measure foam expansion,drainage time, and AFFF concentrations are described in Appendix A.Temperatures, wind speed, wind direction, foam solution flow, foam solutionpressure and other test data (Appendix B) were recorded using a DataAcquisition system. Photographic recordings included two video cameras(equipped with time data generators), one recorder, and two 35m cameras. Apublic address was set up on the main deck and in the control room where thevideo recording equipment was located. Comments made through the publicaddress system were recorded on the video recording system.

6.0 RESULTS AND DISCUSSION

Three pretest fires and 33 fire tests were conducted in the test penaccording to the schedule in Table 1. Data is recorded in Appendix C. Thethree pretest fires were necessary to correctly position the oscillatingnozzle and to determine the appropriate test application rate. Identicalapplication rates and a single nozzle were used in the 21 AFFF concentratefire tests while four nozzles and similar but slightly different applicationrates were used in the 12 nozzles fire tests. Variable application rates wereused in the nozzle testing since a single application rate was not common toeach of the four nozzles.

Only four and one-half minutes of AFFF solution was applied to each of theAFFF concentrate fire tests. This was done to form an even baseline for

17

Sealability Test

ol.

Burnback Test

FIGURE 6.

FIRE PROTECTION AFTER EXTINGUISHMENT

18

comparing the effectiveness of the same quantities of different AFFFsolutions. T~ests were terminated after four and one-half minutes regardlessof whether the flames were extinguished. Dry chemical extinguishers or asecond foam nozzle were used to extinguish any remaining flames. The controland extinguishment times were found to be more rapid when using a manualoperator than with the oscillating nozzle, therefore, only two and one-halfminutes of AFFF solution was applied for each of the 12 nozzle tests.

Al11 the AFFF concentrate tests were successful in bringing the test firesunder control. Because the oscillating nozzle was positioned to project allthe AFFF solution into the pen, certain areas of the pen such as the nearcorners did not have AFFF applied directly tc 1" (Figure 5). In some testsdue to a combination of swirling winds, wind shifts, and the resulting flowcharacteristics of the AFFF being used, the AFFF never flowed or pushed itsway into corner areas to extinguish the flames completely. In these tests theremaining flames were extinguished after the conclusion of the standard foamapplication time. These remaining flames usually covered less than twopercent of the test pen and took less than 15 seconds to extinguish. Detailedr~esults of individual tests are listed and described in the following sections.

6.1 Environmental Factors

Wind was the only environmental factor which had an adverse effect onthe fire test results. Wind effect was more pronounced on the AFFF evaluationtestino than on the nozzle evaluations. Due to the preadjusted nozzleoscillations, computations for sudden wind shifts could not be accomplishedduring a test. Swirling winds or wind shifts created longer control andextinguishment ti'mes in some tests even though all foam was discharged intothe test pen. During the nozzle evaluation, the manual operator attempted toattack the flames so that the wind was coming from behind him. This provedthe ideal firefighting approach as the control and extinguishment times couldbe reduced by approximately 20 seconds when compared to extinguishing the firewhen the wind was blowing directly at the firefighter.

6.2 Pretest Fires

The SFL nozzle on the oscillating base was used to conduct the threepretest fires. Each pretest fire involved 1,000 square feet (92.9m) and wasconducted using 6t, Military Specification AFFF. This was to be the baselineAFFF for comparison since it is the standard foam used on Coast Guardcutters. One pretest fire was conducted at an application rate of 0.04gallons per square foot(l.6 lpmin/sqm). This rate neither controlled norextinguished the f"ire after 12 minutes of AFFF application. The intensity ofthe flames appeared to consume the AFFF as it was applied by the oscillatingnozzle. It was decided to try a second pretest using the same applicationrate but using a different application method. This second method involvedapplying the AFFF only to the front center portion of the pen to first buildup a layer of AFFF in this area to establish control. It was thought thatonce control was established in this area the AFFF would then spread out to

19

extinguish the rest of the flames. This did not happen as planned. After sixminutes of AFFF application only 50% of the flames were extinguished. Theaction of the AFFF as it was applied was being held in check by the flames.The two pretests showed that the AFFF when applied in a passive mode and at alow application rate was not sufficient to control or extinguish the fullyinvolved fire. The flames easily consumed the smaller application rate of0.04 gallon per square foot (1.6 lpmin/sqm). Therefore, it was decided tomake a quantum jump to a 0.1 gallons per minute per square foot(4.07 lpmin/sqm) application rate. If this test application rate provedeffective with the oscillating nozzle, it would also decrease the timerequired for control and extinguishment and reduce the fuel requirementsneeded for testing. This rate was selected for testing since as mentioned inSection 5.5 it has been used effectively in extinguishing fires. To serve ourpurpose, however, the extinguishment rate had to permit a long enough controltime to differentiate between the effectiveness of the different AFFFs.Pretest fire num5er three was extinguished in three minutes and 18 seconds.This extinguishment time and application rate provided good data forcomparison purposes.

6.3 Foam Quality

Foam quality is primarily a function of nozzle design. The samenozzle was used in evaluating all the AFFF concentrates so that differencesinherent to a particular concentrate could be characterized. The foam qualityproduced by the four nozzles described in Section 3.5 was evaluated using the3%" Military Specification AFFF. This AFFF was selected for reasons mentionedin Section 6.3.2.

The foam quality results listed in Table 4 are based on the averageof three observations for each nozzle used. The low expansion ratios anddrainage times were expected as the nozzles used in the testing were designediprimarily for water application. The twin agent nozzle designed for use withAFFF was the exception. As expected, it provided the highest expansion ratiosand longest drainage times. Foam expansion in the 6-15 range and drainagetimes in the 3-8 minute range normally provide the greatest degree of fireprotection after extinguishment.6 Differences in drainage times orexpansion ratios did not appear to affect flame extinguishing capabilities ofthe AFFF solution when discharged on the test fires. The greatest degree offire protection after extinguishment however was found to be provided by AFFFconcentrates having the highest expansion ratio and the longest drainagetimes.

The percent plus or minus deviation for the different foam qualitycolumns in Table 4 were calculated by comparing the highest or lowest singledeviation to the mean of the observations. One explanation for the consistenthigher percentage proportioning rate is that the seawater used in the premixtank was drafted from over the side and could have contained a weak solutionof foam from each prior test. This was because after each test the premixtank was drained and flushed several times over the test ship's side where itmixed with water in Mobile Bay which was then used in the next test.

20

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6.3.1 AFFF Concentrates

The AFFF concentrates and their expansion ratios are listedbelow in order of their decreasing values.

AFFF CONCENTRATES EXPANSION RATIOS3% Light Water, 3% Aer-O-Water 5.9, 5.83% National Universal, 3% Alcohol Type Concentrate 4.2, 4.16% Military Specification 3.43% Military Specification 3.31% Ansulite 3.1

This data shows that the commercial 3% AFFF concentrates and the 3% polarsolvent resistant AFFF concentrates had larger expansion ratios than eitherthe 3% or 6% Military Specification AFFF's or the 1% commercial AFFFconcentrate. Military Specification AFFFs are not equivalent to thecommercial or polar solvent resistant AFFFs in the degree of fire protectionprovided after flame extinguishment. Table 4 also shows that the 3% MilitarySpecification AFFF concentrate and the 6% Military Specification AFFFconcentrate are quite similar when comparing expansion ratios, therebyindicating a close degree of similarity in fire protection afterextinguishment.

The AFFF concentrates are listed below in order of theirdecreasing drainage times:

AFFF CONCENTRATES DRAINAGE TIMES(Minutes)

3% National Universal, 3% Alcohol Type Concentrate 1.2, 1.06% Military Specification .83% Aer-O-Water, 3% Light Water .7, .73% Military Specification .61% Ansulite .4

The data shows that the 3% polar solvent resistant AFFF's had the longestdrainage times wnile the 1% commercial AFFF concentrate had the shortestdrainage time. Drainage times were similar for the 3% commercial AFFFconcentrates, and the 3% and 6% Military Specification AFFF concentrates.Thus the 3% and the 6% Military Specification AFFF concentrates are comparableregarding both drainage times and expansion numbers as previously indicated.

The foam depth measurements in Table 4 represent an averagecoverage of the different AFFF concentrates over the entire test pen surface.

22

The AFFF concentrates and their respective foam depths were averaged for threetests and are listed below in order of decreasing thickness:

AFFF CONCENTRATE FOAM DEPTHSInches (Centimeters)

3% Aer-O-Water 1 1/2 - 2 (3.8 - 5.1)3 % L i g h t W a te r ....3% National Universal ....3% Alcohol Type Concentrate I - 1 1/2 (2.5 - 3.8)6% Military Specification ....

3% Military Specification 1 - 1 1/4 (2.5 - 3.2)1% Ansulite 1/2 - 3/4 (1.3 - 1.9)

A 3% commercial AFFF concentrate had the thickest average foam depth while the1% commercial AFFF concentrate had the thinnest overall foam depth. One 3%commercial AFFF, both polar solvent resistant AFFFs and the 6% MilitarySpecification AFFF, were equal to each other and second in overall depths.The foam depth was slightly greater for the 6% Military Specification AFFFconcentrate than for the 3% Military Specification AFFF concentrate.

6.3.2 Nozzles

The foam quality produced by the four different nozzlesdescribed in Section 3.5 was evaluated using the 3% Military SpecificationAFFF concentrate. This concentrate was selected for several reasons.Presently it conforms to Military Specification MIL-F-24385, is used by theAir Force, and is being evaluated by the Navy. If proven effective for thespecific fire test scenario, it could be considered as an alternative for the6% AFFF concentrate now being used on Coast Guard cutters.

The nozzles and their associated expansion ratios,drainage times, and average foam depths are listed below in their decreasingorder:

NOZZLES EXPANSION RATIO DRAINAGE TIME FOAM DEPTH

Inches (Centimeters)

TAU 5.4 3.8 1/2 - 1 (1.3 - 2.5)MFN 4.5 2.8 1/2 - 3/4 (1.3 - 1.9)SFL 3.3 .9 1/2 (1.3)CGAP 2.2 .8 1/4 (0.6)

The data shows that the highest expansion ratio and drainage times wereproduced by the TAU nozzle while the CGAP nozzle produced the lowest expansionratio and drainage times. The MFN produced the second best expansion ratioand drainage times, while the SFL nozzle was third in foam quality. Theaverage foam depths produced by the nozzles decreases with the expansionratios and drainage times.

23

[ I,,

6.4 Control/Extinguishment Times

The average control and extinguishment times for the fire tests arelisted in Table 5. Each fire test covered 1000 square feet (92.9 sq mi) andhad a fully involved preburn of one minute. Fresh fuel was added to the testpen before each test. This assured the presence of lighter hydrocarbons forsimilar fire severity and decreased the time required for total flameinvolvement of the fuel surface. The fresh fuel insured the same degree ofseverity for conducting burnback and sealability tests.

The same application rate and nozzle (SFL) were used in the AFFFconcentrate tests while different but similar application rates were used inthe nozzle evaluations. A semi-straight stream pattern was used in all testsinvolving the SFL nozzle. This pattern insured that the application of theAFFF solution was confined to the test pen. The MFN was used in astraight-stream pattern due to its tube design construction. The CGAP nozzlewas used in its fog pattern which in effect closely resembled a semi-straightstream. The TAU nozzle was used in a wide-angle fog pattern because of itsfixed nozzle screen.

Individual control times for all fire tests are listed in AppendixC. Control times rather than extinguishment times provided a more accuratereflection of the capabilities of the AFFF concentrates because theoscillating attack pattern and wind shifts created difficulty in totallyextinguishing all flames around the edges of the test pen. This is apparentwhen noticing that 11 of the 21 AFFF concentrate tests required a dry chemicalextinguisher or second foam nozzle to extinguish flames in corners of the testpen where the AFFF concentrate did not reach.

The longer control times in the oscillating mode are a result ofdifferent extinguishing techniques (Figure 7). The oscillating mode used apassive methodical technique of extinguishment while the manual operator useda more aggressive technique. The oscillating nozzle was set at a preset angleand arc of oscillation which methodically covered as much of the entire testarea as possible without wasting any AFFF outside the pen. Because of thispattern, certain corners and edges of the test pen did not receive AFFFdirectly over it and depended upon AFFF piling up and then spreading intothese corners for extinguishment to occur. Even minor swirling winds insidethe test parameters could shift the AFFF around the surface of the test penand cause delays in flame extinguishment around the test pen corners.

Conversely, the manual operator with his aggressive techniqueproduced the quickest control times despite a lower application rate. Thenozzle operator was constantly on the offensive and used aggressive sweepingmotions combined with a rapid advance toward the flames. This close approachto the flames was possible because the nozzle operator was fully dressed in aproximity suit. His support men on the hoseline behind him were also dressedin protective gear consisting of bunker coats, protective headgear, faceshields, and gloves.

AFFF must be sprayed directly on the flames in order to achieve idealextinguishing effectiveness. Piling the foam in one area of the test pen andwaiting for it to spread out over the entire flaming surface was not totallyeffective or sufficient for extinguishment to occur in every test. In a fire

24

4A

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Oscillating (passive)

Manual (aggressive)

FIGURE 7

NOZZLE CONTROL MODES USED

26

situation where it would be impossible for a vessel to maneuver to takeadvantage of the wind, a nozzle capable of projecting foam a reasonabledistance would be required in order for the AFFF to reach and extinguish allof the flames. An example of this would be a fire on a vessel at a dock whichwould require the firefighting to take place regardless of the vessel 'sorientation to the wind.

The AFFF concentrates are listed in Table 5 according to increasingcontrol times. The data shows all AFFF concentrates tested had quickercontrol times than the 6% Military Specification AFFF. Longer control timesof the 60/1 Military Specification AFFF are partially attributed to the windshifts occurring during its fire tests. The data also indicates, however,that the fire extinguishing capablity of AFFF solutions is not dependent uponhigher concentrates to be effective, lower concentrates can be equallyeffective.

The nozzles are listed in Table 5 in order of decreasingeffectiveness. Although the MFN and SFL nozzle exhibited the best overallcontrol and extinguishment times, they did have a slightly higher testapplication rate than the two nozzles they outperformed. The difference inthe application rate between the nozzles creates a question as to whether thehigher application rate or the nozzle effectiveness caused the shorter controland extinguishment times. Although a 40% time difference existed between thenozzles with the shortest control times and the nozzles with the longestcontrol times, this difference jumped to 76% when comparing extinguishmenttimes. Although the rapid knockdown power of AFFF is well documented, it alsoappears that the key to its rapid effectiveness is its widespread deploymentover the entire fire surface. Based upon this premise, the nozzles with thegreatest application rate and the capability to reach out to a fire withoutscattering it would be the most effective. The longer extinguishment times ofthe CGAP nozzle and the TAU nozzle indicate that when using the same AFFF andsimilar application rates on the same fire size, that nozzle design is moreimportant in the extinguishment phase than in the control phase.

Table 5 indicates the MFN and the SFL nozzle as having the bestcontrol and extinguishment times. These nozzles were tested in a straightstream pattern and the test results indicated both were effective in reachinga fire to control and extinguish it. The added foam thickness created by theMFN provided slightly greater control and extinguishment times by retainingbetter control of the areas it passed over. The MFN had only a straightstream pattern and in a close-up fire situation would require banking the foamoff an obstruction. In this type of situation the risk occurs of splashingthe fire in several directions occur due to the force of the straight stream.The SF1 nozzle has the additional design capability over the MFN of projectinga fog pattern at a close-up fire without scattering it to endanger either thefirefighter or the fire area.

The TAU nozzle and the CGAP nozzle were tested at application ratessimilar to the MFN and the SFL nozzle. A fog pattern was used with the TAUnozzle and the CGAP nozzle in order to achieve a similar application rate.The lack of reach attributed to the TAU nozzle and the CGAP nozzle is theprinciple reason for longer control and extinguishmnent times. The nozzleoperator had to move his position several times in order to blanket the entirefire. The time required for this movement rather than the slightly lower

27

application rate is felt to be the reason for the longer control andextinguishment times. There is only a slight time difference required forcontrol between the top two nozzles and between the other two nozzles in Table5. This difference is greater when comparing extinguishment times.

A factor which could affect control and extinguishment times is anerror in the proportioning rate. A premix foam tank was used to prepare thefoam solution concentration to be used in each test. The actual testproportioning rate was checked by the two methods previously mentioned inSection 5.4. Small errors did show up in the actual test proportioning ratesand were attributed to techniques used in filling the tank with AFFF orseawater and the use of the refractometers. The errors in the proportioningrates measurements were quite small and it is felt that the control andextinguishment times of the different AFFF concentrates were not affected.

6.5 Sealability

Each of the AFFF foams tested produced a foam blanket which wassufficient to keep the test fuel from reigniting around the hot metal pipedescribed in section 3.8 and the open flame source above it (Figure 6).Although each of the AFFF foam blankets blackened and bubbled around the hotmetal piping during each test, open flames never broke out. This lack offlame breakout is attributed to the protection provided by the AFFF foamblanket as well as the fuel's overall low volatility. Figure 8 shows thetemperatures recorded by a thermocouple attached to the surface of the pipingused in the sealability testing. The highest temperatures indicated occurduring the fire test when the thermocouple is exposed to the open flamesduring initial testing. As the flames are extinguished the temperatures dropimmediately but then rise again when the propane burner is placed in thepiping to conduct the sealability testing. Even though the hot metal pipingwas above the ignition temperature of the fuel during the sealability portionof the test the hot metal surface did not produce sufficient vapors from thelow volatile test fuel for a flashback to occur. It is obvious, however, thatsome vapors were leaking through the foam blanKet around the hot pipe becausebrief flashes of flames could sometimes be seen in that area. These flasheswere always less than one second long. If the fuel source had been a morehighly volatile fuel such as gasoline, it is questionable as to whether theAFFF concentrations would have kept the fuel from reigniting around the hotpipe surface since the AFFF foam blanket blackened around the pipe to a widthof three inches (7.6 cm).

6.6 Burnback Resistance

Each of the curves in figure 9 and 10 represent the average of 8 to12 data points recorded on the rate and time of fire enlargement during eachburnback test. A curve fitting computer program was used to provide a smoothline curve in order to observe any major differences.

All of the AFFF's tested exhibited varing degrees of resistance inthe burnback tests. Figure 9 shows that three of the 3% AFFF's produced agreater burnback resistance than the 6% Military Specification AFFF while twoof the 3% AFFF's had a burnback resistance slightly less than that of the 6%Military Specification AFFF. The 1% AFFF produced the least effectiveburnback resistance. The test results indicated that a correlation existed

28

S°.

1000-*IGNITION TEMPERATURE OF TEST FUEL

900

c8) OPEN FLAME

700 TEMPERATURE

600-

W.I 500-cr

400- PIPE TEMPERATURE

a 300-

200-.

100.

00 5 10 15 20 25 30

l.-. --.. Sealability Test " "

[4 Control/Extinguishment

Test

TIME (Minutes)

FIGURE 8

PIPE TEMPERATURES IN SEALABILITY TESTS

29

if J.

LEGEND

1% Ansulite

%Military Saectfication Ansute~

3% Nationar nvra

6%Milntary QctcvnAslt

3% 1 Ug n? W a e3% Nati-onaniersa

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11- I

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0 1 2 34 5878910a 910112 21314 15

TIME (Minutes)

FIGURE 9AFFF 8URNBACK RESISTANCE

30

20-190- SFL N0271E TWI VN AGENT

Sa18- NIT NCC -QJ Ar17- L PURPOS

NO ZZLE -- . /

L 14U

<3ILL. 1 -MECHANICA,.L

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13

a- , t I i i I 1 I I0 1 2 3 4, 5 8 7 8 9 10 11 12 13 14. 15

TIME clk'tesj

FIGURE 10

THE EFFECT OF NOZZLE DESIGN ON

BUJRNBACK RESISTANCE

31

''

between visible foam depth and resulting burnback resistance. The greater thevisible foam depth, the greater the burnback resistance, while thinner foamblankets exhibited less burnback resistance. The AFFF's listed in table 5with the greater foam depths show the longest burnback resistance (Figure 9),while the AFFF's with the thinnest foam depths exhibited the shortest burnbackresistance. An example of this is that the 3% Aer-O-Water AFFF produced oneof the thickest foam depths and also exhibited the longest burnbackresistance. At the other end of the scale, the 1% Ansulite AFFF had thethinnest foam layer and the shortest burnback resistance.

The 4 nozzles tested produced foams with a range of differentburnback resistance. The MFN produced foam with the best burnback resistancewhile the TAU nozzle was second. The SFL nozzle produced foam which was thirdin burnback resistance while the CGAP nozzle's foam was rated last. The testresults indicate that the nozzles which produced the greatest foam depths(Table 5) also had the greatest burnback resistance (Figure 10).

7.0 SUMMARY/CONCLUSIONS

7.1 AFFF Concentrates

The test program showed that all the AFFF's tested (section 2.0)were as effective as or comparable to the 6% Military Specification AFFF incontrolling and extinguishing deck spill fires involving a low volatile ClassB fuel. The 3% Aer-O-Water AFFF and the 3% Military Specification AFFFexhibited the best overall control times while the 3% Light Water AFF7 and the6% Military Specification AFFF had the longest control times (i.e. poorerresults). It is felt that the control times of the 3% light water AFFF andthe 6% Military Specification AFFF were attributed to the shifting windconditions which occurred during the testing of these AFFF's rather than tothe characteristics of the agents themselves. The 3% National Universal AFFF,the 3% Alcohol Type Concentrate AFFF, and the 1% Ansulite AFFF exhibitedsimilar control times which were between the AFFF's with the shortest controltimes and the AFFF's with the longest control times.

Each of the AFFF's tested exhibited a resistance to foam breakdownaround the hot metal piping which was sufficient to prevent a reflash fromoccurring from the open flame source above the piping. The test resultsindicated that an AFFF's ability to resist breakdown around hot metalobstructions is closely linked to the depth of the foam around the hotobstruction. The AFFF's which produced the greatest foam depth also providedthe greater resistance to blackening and edging away from the hot metalsurfaces which in turn prevented the release of flammable vapors. AFFF'swhich produced thin foam layers exhibited less resistance to blackening oftheir edges and agreater recession from the hot metal piping. A reflash did not occur aroundthe hot metal piping in any of the testing. It is felt that a reflash did notoccur because of the fuel's low volatility and the action of the AFFF.

The 3% commercial AFFF's produced the most effective burnbackresistance while the 3% polar solvent resistant AFFF's were second. The 3%and 6% Military Specification AFFF's were comparable and also third in rankingby burnback resistance. The 1% AFFF was the least effective of AFFF's inburnback resistance. A significant difference existed between the burnbackresistance of the most effective 3% AFFF compared to that of the 6% Military

32

Specification AFFF. Only a minor difference existed between the burnbackresistance of the least effective 3% AFFF when compared to the 6% militaryspecification AFFF.

Test results demonstrate that 3% Military Specification AFFF couldreplace 6% Military Specification AFFF on Coast Guard cutters without a lossin fire fighting performance. The 3% Military Specification AFFF exhibitedcontrol times superior to those of the 6% Military Specification AFFF. It isfelt, however, that the longer control times of the 6% Military SpecificationAFFF were attributed somewhat to swirling wind conditions occurring during thetesting and not to foam characteristics. It was noted throughout the testingthat slight shifts in wind directions occurring during a test could add 20 to30 seconds to a control time effort. The 3% Military Specification AFFF didexhibit a slightly shorter burnback resistance than the 6% MilitarySpecification AFFF but the difference, as noted in figure 9, is insignificant.

The conclusion that a 3% AFFF concentrate could replace the 6%Military Specification AFFF concentrate used on Coast Guard cutters was basedon accurate foam proportioning. Test results indicate that the amount of AFFFconcentrate in the foam solution plays an important part in making a fireresistant foam. This can be seen in Figure 9 which shows the 1% AFFFconcentrate as being less effective in its burnback resistance compared to theother AFFF's. Because a premix tank was used in the testing, the proper AFFFproportioning was always maintained. No attempt was made to use or to testthe accuracy of various AFFF proportioners used on Coast Guard cutters. Thistype of testing and sensivity testing of the firefighting performance tovariations in proportioning should be considered if lower percentage AFFFconcentrates are to be considered for use on Coast Guard cutters.

7.2 Nozzles

The four nozzles tested were effective in controlling andextinguishing the deck fires when using the 3% Military Specification AFFF.:t was clearly demonstrated, however, that the effectiveness of a nozzle usingAFFF for controlling and extinguishing deck fires is greatly increased when itis uperated in a mode which can cover the entire fire area. This is evidencedby the shorter control and extinguishment times of the two nozzles (MFN andSFL) used in a straight stream mode when compared to the longer control andextinguishment times of the two nozzles (CGAP and TAU) which were operated ina fog pattern mode. In the fog pattern mode the operator had to repositionhimself several times to attack the fire because the pattern could not coverthe entire flame surface. Additional nozzle operator movements and lack ofreach were responsible for the longer control and extinguishment times. Thisis demonstrated clearly by the increased time difference in the finalextinguishment phase rather than the control phase (table 5) of the nozzlepatterns in use. The quick knockdown characteristics of AFFF was quiteevident but the test results also indicated that the AFFF must be spreadrapidly across the entire flame surface to be utilized to its fulleffectiveness. This effectiveness will be reduced by tending to pile the AFFFin one area and waiting for it to flow across the flame surface.

The MFN and the SFL nozzle had the shortest control and extinguish-ment times while the CGAP nozzle and the TAU nozzle had the longest controland extinguishment times. The SFL nozzle with its multiple control modes

33

I'

permitted it a greater flexibility which made it a more versatile and overall

effective nozzle. Test results show the MFN produced a foam which had the

longest burnback resistance, the second highest expansion ratio and the second

longest drainage time. The twin-agent nozzle especially designed for AFFF fog

usage gave as expected the highest expansion ratio and the longest drainage

but it came in second in the burnback resistance. The foam this nozzle

produced was blotchy in covering the test pan. Because of this the fuel

surface was not covered by a visible foam and was quick to ignite. Although

the SFL nozzle produced foam which was third in burnback resistance, expansion

ratio and drainage times compared to the MFN or the TAU nozzle, it could

function in both their modes and still be equally effective. The CGAP nozzle

provided foam with the worse burnback resistance and the lowest expansion

ratio and drainage time. It was the least effective of the nozzles.

34

REFERENCES

1. Commandant Instruction M9000.6, 1983 edition, Chapter 555 - Firefighting.

2. Fire Protection Systems, National Foam Engineering Manual, 1979.

3. "Light Water" AFFF Products and Systems, 3M Engineering Manual, 1982.

4. Military Specification MIL-E-24385, 26 April 1982, Fire ExtinguishingAgent, Aqueous Film-Forming Foam (AFFF), Liquid Concentrate, for Fresh and SeaWater.

5. Commandant Instruction M16465.12, October 1978, Hazardous Chemical Data.

6. National Fire Codes, Standard for Evaluating Foam Fire Fighting Equipmenton Aircraft Rescue and Fire Fighting Vehicles, NFPA No. 412, 1974.

7. McDaniel, Dale. Report of Deck Foam Fire Extinguishing Test AboardM/V RHODE ISLAND. Department of Transportation and U.S. Coast Guard,June 1972.

8. Beene, Jr., David, and Richards, Robert. Automated Deck Foam FireExtinguishing Systems for Tankers. Department of Transportation and U.S.Coast Guard, April "19//.

9. Geyer, George; Neri, Lawrence; Urban, Charles. Comparative Evaluation ofFirefightin Foam Agents. Department of Transportation. Federal AviationATdministration. August 1979.

10. Geyer, George. Equivalency Evaluation of Firefighting Agents and MinimumRequirements at U.S. Air Force Airfields. Department of Transportation.Federal Aviation Administration. November 1982.

11. Geyer, George. Assessment of the Requirements for Combatting AircraftCarrier Flight Deck Fires. Department of the Navy. November 1982.

35

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APPENDIX BINSTRUMENTATION

Title: AFFF Deck FiresChannelNumber Instrument Description Location Output Range In Engineering inits0 Thermocouple, Type K F w test coaming, 0-.38F (O-IO00UC1

inconel - sheathed 10 ft from Stbd test coaming

I Thermocouple, Type K Fwd test coaming, 0-538OF (0-10000C)

incooel - sheathed 10 ft from Port test coaming

2 Thermocouple, Type K Port test coaming, 0-5380F (O-100C)

inconel - sheathed 10 ft from Fwd coaming

3 Thermocouple, Type K Port test coaming, 0-538OF (0-lOO0OC)inconel - sheathed 10 ft from Aft coaming

4 Thermocouple, Type K Aft test coaming, 0-538OF (O-lOOOOC)inconel - sheathed 10 ft from Port test coaming

S Thermocouple, Type K Aft test coaming, 0-538OF (0-1000oC)inconel - sheathed 10 ft from Stbd test coaming

6 Thermocouple, Type K Stbd test coaming, 0-538OF (0-lO00C)inconel - sheathed 10 ft from Aft test coaming

7 Thermocouple, Type K Stbd test coaming, 0-538oF (0-1OOOOC)Inconel - sheathed 10 ft from Fwd test coaming

8 Thermocouple, Type K Reignition source, 0-538OF 10-IO00OC)incone) - sheathed corner pipe (Aft-Stbd)

g Thermocouple, Type K Reignition source, 0-538OF (O-1O00oC)inconel - sheathed pipe burner (flame)

10 Thermocouple, Type K Water in test 0-5380F (0-1O000C)inconel - sheathed pen

11 Thermocouple, Type K Foam solution 0-538oF (0-10000C)

quick lip in tank

12 Wind Direction 02 deck, FWD 0-3600T

13 Anemometer 02 deck, rnid-ship 0-50 mph

14 Barometer Trailer 27-31.5 in. of Hg

15 Fire Main Pressure At nozzle 0-120 psi (0-827 kN/m2)

16 Foam Solution Flow At nozzle 0-150 gpm (568 lpm)

17 Ambient temperature Outside trailer 0-538OF (0-1000oC )

18 Calorimeter Aft of test pen 0-15 Stu/sq ft/sec(0-145 kW/sq m/sec)

Ig Radiometer Aft of test pen 0-5 Btu/sq ft/sec

0-51 kW/sq n/sec)

20 Humidity Outside trailer 0-100% R.H.

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