Document qmGqqBEbDeLg8K1XYE9ppLp5

f fffc\ AFFF Update. Fire Fighting Foam Coalition 1001 19th Street North AFcraloxinr(gt(i55nt7o7aw1n1e)w,)Sc33Vw@u8A8i.t4cfe4f2o--fc277x1.299.2on1050re5g990t September 2011 Milspec Testing of AFFF and Fluorine-free Foam Special Edition and isooctane. It is difficult based on such limited data tboetwdreaewn failnmy ffoirrmmactioonnclaunsdionbsurnabboacukt ptheerforremlaatinocnes.hip Executive Summary At the 2011 SUPDET Conference in Orlando, the Naval Research Laboratories (NRL) presented the results of fire testing of AFFF agents and fluorine-free foam1. Although the testing was limited in scope, it provided clear evidence of the importance of film for mation to foam performance. Extinguishment times for AFFF agents on 28ft2 pool fires tested at full strength were on average 77% faster for gasoline, 88% faster for methylcyclohexane (MCH), and 70% faster fifsooorromhcetapantaefni,lemwwh, ehfrleeunothrcieonmete-pfsrtaeerededAfotFoaFmFfluaeogxretiinnnetgs-ufwrieseehreefdouantmahbe. leFfitoroer about 10% faster. AFFF agents extinguished all gasoline and heptane fires in less than 30 seconds, the time required to pass the military specification (milspec). The fluorine-free foam was unable to extinguish any gasoline or heptane fire in less than 30 seconds. Foam agents must meet the requirements of the milspec in order to be listed on the US Department of Defense qualified products database t(hQePFDe)dearnadl Ausveiadtifoonr Amdilmitainryistarpaptiloicnat(iFoAnsA.) Irneqaudirdeistioanll US airports to carry AFFF agents listed on the QPD2. Burnback times were similar among the foams tested. AFFF agents performed on average 37% better on heptane and 28% better on gasoline. AFFF agents and fluorine-free foam performed almost identical on MCH Introduction AFFF is the premier fire fighting foam in the United States (US) and many parts of the world. Its ability to rapidly extinguish flammable liquid pool fires is unmatched by any other agent. AFFF agents are fusousrerfmdacutmlaanatetisnd.lyWbyahs ecfnoomammbiiixnnegindgawgheintyhtdsrwowcaaitterhbr,opntehrefsluurrofearsicuntlaatitnnetdgs solution achieves the optimum surface and interfacial tension characteristics needed to produce an aqueous film that spreads across the surface of a hydrocarbon fuel. It is this film formation feature that provides sduepsiegrnioartiofinre- eAxqtiunegouuisshFmilemntFaonrmd iinsgthFeoasmou(rAceFFoFf).the Over the past decade, most foam manufacturers have developed fluorine-free foam products to offer as TphyohdteersnoetciafaorlbamoalnsterufnsoauataimvlleiynsgctoonagtAaeiFnntFsFhiaginhndersoocmtohneecreanpitnprglaitrcieaodtniioesnnosts.f in order to make up for the lack of film forming fluorinated surfactants. Although they do not contain persistent chemicals, fluorine-free foams have an environmental profile related to biodegradation, acute toxicity, chemical oxygen demand (COD), and biochemical oxygen demand (BOD) that is similar to AFFF. A study of commercially available fire fighting foam agents indicates that some fluorine-free foams are at least an order of magnitude higher in aquatic toxicity than AFFF agents3. US00007916 Military Specification Ts(mthaineldspUaerSdc)sDfioesrpofainrrteemfioegnfhtttihonefgDfmoeoafmestnssreiingmothrioeliutwasroyarlndsdp. eIcrteifsiispcmeactoitoernde difficult to meet than other standards such as ISO and UL, and there are many foam products that meet the requirements of those standards but do not meet the requirements of the milspec. These requirements include conformance to concentration as determined by refractive index and fluorine content; corrosivity (pH, total halides, general and localized corrosion); storage issues related to compatibility with other AFFF agents and stability based on aging of the agent; efaanncvdtiorrobsni,omlsopegenictcaiaflilciamollxpyya,gccethnaesmddeiecmtaelarmnodixnye(gdBenObyDdbe)i,modaaenngddra(daCaqbuOialDittiyc) toxicity (short term measurement for salt water Killifish); performance as a film forming agent (dry chemical compatibility, film formation and sealability, viscosity, spreading coefficient, and foamability); and, finally, fire performance on a 28 and 50ft2 unleaded gasoline pool fire. As part of the fire performance taetshtianlgf-sftoraemngtahg4e.nts must extinguish the 28ft2 pool fire NRL Foam Testing Taghernetes cliosmtemd eornciathlley QavPaDilabalnedfofalumoriangee-nfrtse,etwfooamAFthFaFt Nt2h8ReftLm^ iphlsoaposelcpfrinreoevziuzoslueins,lgaypfpowluoircrakdteiifodfnewrreainttthe,,fuawenlesd.retAetsleltsttpeesrdtostoouncseodal wdeistihgnfrsetrsehngwtha.ter and the foam mixture at its full Gasoline and heptane were tested to collect data comparing the two fuels for a possible changeover to heptane as the milspec test fuel in the future. The comparison of MCH, isooctane, and heptane was part of a mechanistic study to isolate the different factors influencing suppression and burnback. These three fuels were chosen to vary the spreading coefficient for AFFF agents while keeping the fuel flashpoint nearly coofnfustealnftl.asPhpreoviinotuoslny tNheRmL ehcahdanloisomkeodf abtutrhnebaicnkfl.uence Results tFmiimirleespsoeuacrteretiqpmureeirsseemnarteeendptsri,ensaeTfnoatbaemlde ia2ng.eTnIatnbmleoursd1teaernxttdoinbgmuuerinsehtbatthhckee 28ft2pool fire at full strength in 30 seconds or less and have a burnback time of at least 360 seconds. Table 1: Fire Out Times (seconds) Fuel A(6F%FF) A(3F%FF) Fluo(r6i%ne)-free Gasoline 22 21 35,41 Heptane 23, 28 25 43 MCH 22, 23 19, 20 33, 46 Isooctane 32, 33 32, 33 29, 30 AFFF agents extinguished the test fires in an average time of 21.5 seconds for gasoline, 25.3 seconds for heptane, 21 seconds for MCH, and 32.5 seconds for isooctane. The fluorine-free foam extinguished the test fires in an average time of 38 seconds for gasoline, 43 ssaeegcceoonnntsddsswffeoorrreihsoeonpotcaatnvaeenr,ea.3g9eE.5x7t7si%necgoufniasdshstemfroefrnotMrtigCmaHseos,lifanonerd,A82F89F%.F5 faster for MCH, and 70% faster for heptane when compared to fluorine-free foam. For isooctane, where the tested AFFF agents were unable to form a film, fluorine-free foam extinguished the fire about 10% faster. AFFF agents extinguished all gasoline and heptane fires in less than the 30 seconds required to pass the milspec. The fluorine-free foam was unable to extinguish any gasoline or heptane fire in less than 30 seconds. Table 2: Burnback Times (seconds) Fuel A(6F%FF) A(3F%FF) Fluo(r6i%ne)-free Gasoline 652 657 512 Heptane 878, 758 674 563 MCH 522 499 503 Isooctane 767 820 789 US00007917 Burnback times were similar among the foams tested. AFFF agents performed on average 37% better on heptane and 28% better on gasoline. AFFF agents and fluorine-free foam performed almost identical on MCH and isooctane. Both the AFFF agents and the fluorine-free foam had burnback times for gasoline and heptane that were well in excess of the 360 seconds needed to pass the milspec. Discussion Aitldthifofuicguhltthtoe dlirmawitemd asncyopceooncfltuhseioNnsR, Lit tdeosteisngcomnfaikrems the already well-known fact that the ability of fluorosurfactant foams to form an aqueous film on hydrocarbon fuels is the key to exceptional extinguishing performance. AFFF agents performed significantly better than fluorine-free foam on fuels where they could form a film, but performed similar to fluorinefree foam when they could not form a film. It should bcoemnmotoend ftlhaamt mAaFbFleF, hagyednrtoscafrobromn aliqfuilimds osnuchmoasst gethmaeseorolginnelenycafyonasdimtujeaattgioefnnustes.l Tatphhpaisrtoivwseowduhlfydorthbmeeyileictnaocrnoytuionnruteeareitrdopobirnet use in the US. In order to compensate for the lack of film formation, fluorine-free foams rely upon having a good enough foam blanket in terms of expansion ratio and drainage rate. Expansion ratios for foams generated using the milspec nozzle in this study were high, in the range of 9:1 to 10:1. These are much higher expansion ratios than would be expected from the equipment used by tmnooons7-ta:1fsipreifrfoairgtehdateirfrosaaimnsp.tihraEetxefdpiealndfs,oiawomnhircaahtniodarse3ol:if1k9e:l1tyotaon5d:b1e105f::o11r would be expected to enhance the effectiveness of fluorine-free foam by producing a thick foam blanket that is unlikely to be achieved in real life situations. AFFF agents on the other hand actually perform better with lower expansion ratios similar to what would be expected in the field. Additional testing on the 50ft2 pool fire and the 28ft2 pool fire at half-strength, as required under the milspec, pcoeruflodrmaalnsoce baendismhpouolrdtabnet coinnsibdeetrteedr indefufitnuirnegstufdoiaems. References 1 Extinguishment and Burnback Tests of Fluorinated and Fluorine-free Firefighting Foams with and without FCihlmristFooprhmeartioBnu,ttBerrwadolertyh,WZillaicahmasr,yTiBmuorgthery, MRuornraalyd, JSohheninsFoanrl,eyJ,amNeasvaFl leRmesineagr,chClLaarebnocreatoWryh, iWtehaushrsint,gtaonnd, DC, presented on March 25, 2011, at the SUPDET Conference,www.nfpa.org/assets/files//PDF/Proceedings /SUPDET 11WilliamsPaper.pdf. 2 FAA Advisory Cautionary Non-directive (CertAlert), AANqdoum. ei0onu6iss-0trF2ai,tlimoFne,FborNurmaatriiyonng8a,Fl o2Pa0amr0t6m13ae9netdiCngeFretMdAeIlreLarl-tFAN-2vo4i.a3t8i1o51n, 02, Identifying Mil-Spec Aqueous Film Forming Foam (AFFF), February 15, 2011 3 96-hour LC50 Value in Fathead Minnows (flow-through test), Report of tests on six fire fighting foam agents performed by Aqua Survey Inc., Flemington, New Jersey, USA and 96-hour LC50 Test in Fingerling Rainbow Trout, Report of tests on six fire fighting foams agents performed by Harris Industrial Testing Service Ltd., Nova Scotia, Canada 4 United States Department of Defense Military Specification, Mil-F-24385, "Fire Extinguishing Agent, Aqueous Film Forming Foam" US00007918