Document pm7a9w43k7ZGLDmM9nx0BnXxw

fround and Needs What kinda foam do you want with those fries? There are a variety of needs and a variety of standards US00007885 Foam Flavors Protein: "Processed" waste stream proteins FP: FluoroProtein, i.e., protein + fluorosurfactant FFFP: Film Forming FluoroProtein AFFF: Aqueous Film Forming Foam MilSpec AFFF: AFFF passing DoD qualification testing AR (Alcohol Resistant) Variants Sticky foams - 3-D capability for Class A fire scenarios US00007886 ill VV / Ship - Aircraft Carrier Flight D eck 1* W eapons co o k -o ff potential N eed for occupant rescue Greatest potential for immediate multi-plane incident from crash into pack o f aircraft M inim al separation distances betw een A/C, betw een ordnance items, and betw een A/C and ordnance Proximity of threat area to occupied areas H igh value asset Potential for battle damage Ship- H elicopter Flight Deck 2 Same as flight deck, but less potential for multi-plane incident, low er parking density (greater separation distances), and lesser amounts of ordnance Ship- Aircraft Carrier H angar & Amphib W ell D eck 2 Same threat as flight deck, but less probability for sudden m ulti-plane incident and less ordnance Ship- H elicopter H angar on Large D eck A m phib 3 Less ordnance relative to aircraft carrier hangar Ship- M achinery Spaces 3 H igh value asset. B ut no ordnance exposure and minimal life safety threat Ship- Single Helo H angar on Small Ship 4 Single aircraft, m inim al ordnance, negligible life safety threat Shore- CFR Apparatus 2 Need for occupant rescue, weapon cook-off potential Shore-Aircraft Hangar 2 Concentration o f high value assets Shore- H ot Refueling Stations 2 Need for occupant rescue, weapon cook-off potential Shore- H ush Houses, Fuel Farms, Structural Pumpers 4 Physically separated assets, m inimal life safety threat * Priority relative to need for rapid pool fire extinguishment US00007887 Background and Basics AFFF developed in the early 1960's by NRL and 3M to provide better fire protection than was provided by protein foam Class B (liquid fuel) fires in "pools," 2-D, not 3-D Hydrocarbon foaming agents Fluorinated surfactant (required by MilSpec) Specification includes a number of performance and physical property requirements US00007888 The Need for AFFF Many applications worldwide depend on the capabilities of the US military developed AFFF The US military performance requirements for life safety and critical national security asset protection cannot be reduced Many worldwide applications, as well as some military applications, may be able to be satisfied with other than MilSpec qualified products, depending on threat scenario specific protection requirements US00007889 Background AFFF is a vital component of Navy and DoD fire protection for rapid extinguishment of fuel pool fires when a - Pool fire threatens high value assets (such as multiple aircraft and / or aircraft carrier) - Pool fire occurs under an occupied aircraft (must maintain fuselage integrity and rescue occupants) - Pool fire exposes weapons to potential "cook-off' (e.g., aircraft carrier flight deck) Use extends into civilian sector US00007890 Issues The use of AFFF in the future may become more restricted or some uses eliminated because of environmental regulations: potential categorization as "PBT" - Persistent Bio-accumulative - Toxic - Effects to air, water, and wastewater streams Foaming Biochemical and Chemical Oxygen Demand Aquatic Toxicity Hazardous Air Pollutants US00007891 Surfactant Role in AFFF Purpose of surfactants is to reduce surface tension A Fluorinated surfactants allow foam to be produced spontaneously upon ejection from a r ` ated nozzle Even without foam, surfactant allows aqueous layer to cover fuel, even though the water is 1 , and has intrinsic . V \ \ FOAM FILM FUEL US00007892 What are surfactants? Surfactant = SURFace ACTive AgeNT Compound properties Soluble (usually in water, but also oils and other organic solvents) Changes surface activities between materials - Surface tension - Interfacial tension Most common examples are soaps and detergents US00007893 Why do we need surfactants? Surfactants can accomplish many small-scale tasks due to their unique structure and physical properties Surfactants are used for Drug Delivery Textiles and Cleaning Electronics Substrates Film Handling Agriculture Mining Fire Protection US00007894 Why are surfactants so special? Present in very small quantities, but have significant effect on properties of the bulk Surfactant theory involves both transport and thermodynamic considerations Especially important in situations where phase boundary area is large relative to system volume (e.g. films, puddles, bubbles) Many surfactants of different structures can produce similar physico-chemical effects US00007895 AFFF Surfactants Are long chained with hydrophobic and hydrophilic ends Reduce water surface tension Reduce hydrocarbon surface tension Effective in presence of dry chemical agents Solution that drains out from foam is film-forming on hydrocarbon fuels US00007896 What's In A Name? US DoD AFFF MilSpec requires the use of a fluorinated surfactant PFAS Main AFFF example is PFOS (8 carbon skeleton) from 3M Persistent, Bioaccumulative and Toxic (PBT) Manufacturer phase out EPA SNUR ban future manufacture and import. PFAA E.g., PFOA --C-8, PFHxA --C-6 (Not used in manufacture of AFFF) Similar concerns and regulatory review as PFOS Telomerization Process Used to make fluorosurfactants for AFFF Usually C-6; No / Fittle PFOA or PFOS (But C-6 may degrade to PFHxA) Persistent Industry and regulatory review of bio-accumulation and toxicity of perfluorosurfactant telomers and degradation products US00007897 Fire Performance Evaluation Photos show qualification testing of AFFF in 28 ft2 gasoline pan fire. Requirement for extinguishment is 30 seconds. Other tests include salt water dilution of concentrate, V2 strength solution, simulated aging, and 50 ft2pan fire. Applying AFFF Almost Extinguished US00007898 AFFF Performance Prevents radiation from reaching fuel Retards pyrolyzates and fuel from reaching flame Absorbs heat Cools fuel Rapidly spreads, covers and reseals fuel surface US00007899 Key Properties Surface Tension Viscosity Foam quality Drainage Thermal stability Film fire protection US00007900 Understanding Aqueous Film Forming Foam Simplistic model uses two interacting fluids AFFF is less dense and more viscous Use oil over water principles Very simplistic model does not accurately determine spreading Reality: non-Newtonian behavior greatly complicates modeling Surfactant diffusion, adsorption, and solubility further complicates modeling Need model complicated enough to capture essential behaviors, but still manageable US00007901 MilSpec AFFF Capabilities No other agent can equal its ability to rapidly extinguish a pool fire Rapidly spreads, covers and reseals fuel surface Vital to confronting: Potential ordnance cook-off Pool fires threatening aircraft crew Threat to concentrated high value assets We effective foam, and It must be environmentally acceptable US00007902 AFFF Uses Rapid extinguishment of pool fires Flight decks, bilge spaces of Halon (and Halon replacement) protected areas Flight lines Facilities Training AFFF used for a hierarchy of needs, from Critical, to lower threat level applications US00007903 Extinguishment with AFFF The foam blanket covers the fuel surface Prevent radiation from reaching fuel Prevent pyrolyzates from reaching flame Water drains out and cools the fuel Film self-seals the fuel surface, eases foam spread Functions with salt or fresh water Does not work well for three-dimensional fires US00007904 Fate of Surfactants in AFFF Biodegradation Straight-chain hydrophobic groups decompose better than branched-chain or ring-containing groups, although they are less soluble in water and/or hydrocarbons than branched chains or rings Fluorocarbon chains are resistant to biodegradation even when straight US00007905 Wastewater Treatment Plant Generally recognized that the water reaching the treatment plant cannot have a greater concentration of AFFF than 1700 ppm* 6-million gallons per day plant can handle 7 gpm of solution. Medium Sized City Can take days or weeks to process foam depending on the discharge. *Department of the Army Technical Letter No. 1110-3-481, 23 May 1997 US00007906 Operational Restrictions Limitations already exist Training and ship testing protocols have been changed in response Restrictive regulations continue to evolve (UNDS) Need to anticipate impact of future regulations US00007907 Where Are We? Research on firefighting foams is ongoing Only recently has literature become available for review to begin to fully understand surfactant solution properties when spreading on liquid substrates Some avenues of research are only now beginning to be possible US00007908 Environmentally Friendly Foams Physical modeling/scaling - understand fundamental extinguishment mechanisms - Create, refine models - Verify model performance - Correlate with intermediate and large scale testing - Evaluate new formulations Chemical formulations - Non-fluorosurfactant film-formers - "Biodegradable" fluorosurfactants - Novel, "designer" chemicals US00007909 Conclusions AFFF is a fast and efficient way to extinguish two dimensional liquid hydrocarbon pool fires DoD, especially US Navy, has long record of being proactive in protecting the environment Continuing accumulation of information on harmful effects and international concerns and restrictions make it prudent to explore future options Better definition of user needs, as opposed to desires, will enable more options to be considerec Improved understanding of AFFF action will lead to design of less environmentally threatening products, while maintaining required fire protection capabilities US00007910 Onward for Environmentally Friendly Fire Fighting Foams US00007911 Composition and Proposed Film Structure of AFFF Chemical composition of 3M AFFF concentrate AFFF composition is a complicated proprietary mixture unique to each manufacturer. Concentrate is mostly water, glycol ethers to increase viscosity => extend foam lifetime. Contains both fluorocarbon and hydrocarbon surfactants. chemical name percent of total composition w a te r diethylene glyco! butyl ether (butyl carbltoi) am photeric fluoroalkylam ide derivative alkyl sulfate salts perfluoroalkyl sulfonate salts triethanolam ine tolyitriazole (corrosion inhibitor) 69.0 -- 71.0 20.0 1-- 5 1.0-- 5.0 0.5-- 1.5 0.5-- 1.5 0.05 AIR Fluorocarbon surfactant thought to predominate at water/air interface, hydrocarbon surfactant at water/fuel interface. HYDROCARBON PHASE US00007912