Document RajrJBbXY99VRE5gXBGM3xY87

DEPARTMENT OF THE NAVY NAVAL RESEARCH LABORATORY 4555 OVERLOOK AVE SW WASHINGTON DC 20375-5320 IN REPLY REFERTO 3900 Ser 6180/0071 MAR 3 1 2014 From: Commanding Officer, Naval Research Laboratory To: Commander, Naval Sea Systems Command (Code 05P M. Hunstad) Subj: COMPARISON OF COMMERCIAL GRADE HEPTANE WITH UNLEADED, ETHANOL-FREE GASOLINE AS FUELS FOR AFFF QUALIFICATION TESTING UNDER THE MIL-F-24385F PROTOCOL - FINAL REPORT Enel: (1) One copy o f subject report 1. Enclosure (1) is forwarded for your information and review. 2. This report documents the results o f the Aqueous Film-Forming Foam (AFFF) fire tests comparing the fire extinguishing performance o f AFFF products appearing on the MIL-F24385F Qualified Products List (QPL) when using either heptane or gasoline as the test fuel. This project was sponsored by the Naval Sea Systems Command (NAVSEA) under the Cross Platform Systems Development Program, Task Number 3.13.10 / MILSPEC AFFF Re-Baseline. 3. The overall finding o f this test series confirms the acceptability o f changing the test fuel for AFFF MILSPEC qualification testing to commercial grade heptane with a boiling point range o f 87-105 C. 4. In addition to recommending changes to the AFFF MILSPEC fire test protocol, the AFFF Re-Baseline project also identified additional chemical and physical MIL-F-24385F requirements that could be modified including changes to Fish Toxicity testing, Halide Concentration testing, Biological Oxygen Demand (BOD) testing, Index of Refraction testing, Packaging and Shelf Life requirements. 5. The Naval Research Laboratory's points of contact are John P. Farley, Code 6186, (202) 404-8459, e-mail: iohn.farlev@nrl.naw.mil and Dr. Bradley A. Williams, Code 6185, (202) 767-3583, e-mail: bradlev.williams@nrl.naw.mil. By direction US00000881 6180/0071 A:JPF 28 March 2014 Comparison of Commercial Grade Heptane with Unleaded, Ethanol-Free Gasoline as Fuels for AFFF Qualification Testing under the MIL-F-24385F Protocol - Final Report Ralph Ouellette Hughes Associates Inc. Baltimore, MD John P. Farley Clarence L. Whitehurst Bradley A. Williams Navy Technology Centerfo r Safety & Survivability Chemistry Division Washington, DC Enel (1) to NRL Ltr 3900 Ser 6180/0071 DISTRIBUTION STATEMENT D: Distribution authorized to the Department of Defense and U.S. DoD Contractors only; Critical Technology, March 28, 2014. Other request shall be referred to the Naval Sea Systems Command (NAVSEA), SEA 05P, 1333 Isaac Hull Ave, Stop 5050, Washington Navy Yard, DC 20376 US00000882 COMPARISON OF COMMERCIAL GRADE HEPTANE WITH UNLEADED, ETHANOL-FREE GASOLINE AS FUELS FOR AFFF QUALIFICATION TESTING UNDER THE MIL-F-24385F PROTOCOL - FINAL REPORT 1.0 OBJECTIVE Aqueous Film Forming Foam (AFFF) is an important component of Department of Defense (DoD) fire protection against liquid fuel fire threats, particularly on carrier flight decks, landbased aviation facilities and fuel storage depots. MIL-F-24385F [1] is the current DoD qualification protocol for AFFF. "MILSPEC" qualified AFFFs are required for designated applications aboard Navy ships and other DoD facilities, and are also widely used in civilian applications, especially in airports and fuel storage facilities. NAVSEA Code 05P is the Technical Warrant Holder (TWH) for the MIL-F-24385F standard and the Qualified Products List [2] for MILSPEC AFFFs. Currently, the fuel used for MIL-F-24385 testing is unleaded gasoline [1], This fuel was chosen in part because it is commonly available and has a low flash point, typically about -40 C. Most fuels which are common fire threats in DoD applications, such as JP-5, JP-8, and F-76 diesel, have much higher flash points; therefore testing the AFFF on a lower flash point fuel is believed to provide an additional safety factor. At the time the MILSPEC was first established, JP-4 (the military version of Jet-B) was in common use; this fuel also has a low flash point (typically around -18 C). This may have been an additional motivation for the choice of gasoline as the AFFF MILSPEC test fuel. Recently, use of unleaded gasoline for AFFF testing has been complicated by the addition of ethanol to gasoline in many areas. In designated areas, the addition of ethanol at the 10% level (E10) is mandated for environmental reasons. The NRL test facility at the Chesapeake Bay Detachment, in Chesapeake Beach, MD, is located in an area where ethanol is required to be added to gasoline. Although NRL has obtained an exemption from the Environmental Protection Agency (EPA) to purchase non-ethanol-containing gasoline for AFFF fire testing, locating suppliers who can provide such gasoline is made difficult by tax credits given for renewable fuels (including ethanol) which lead many distributors to supply E10 even in instances where its use is not mandated. MILSPEC AFFF is not intended for use on water miscible fuels, as these fuels are known to disperse foam and interfere with AFFF's performance. Even a 10% ethanol concentration in gasoline might impact the performance of a candidate AFFF under the very stringent test protocol required for AFFF MILSPEC qualification. Therefore E10 cannot be used for MIL-F24385 qualification testing. Additionally, the flashpoint and vapor pressure of gasoline varies with the geographical location and time of year, as a compromise between ease of starting an engine and minimizing fugitive emissions. The issue of gasoline having variable properties which might influence AFFF performance in MIL-F-24385 qualification tests has been raised in the past by AFFF manufacturers. Therefore, NAVSEA, in consultation with NRL, desired to explore the use of a different fuel for AFFF qualification testing. After considering possible fuel choices, commercial grade heptane 2 US00000883 has been identified as a candidate fuel as a replacement for gasoline in future AFFF qualification tests. Heptane is currently used as the test fuel in some commercial certification standards [3], The present test report documents the results of the AFFF fire tests comparing the performance of AFFFs appearing on the MIL-F-24385F Qualified Products List (QPL) between heptane and gasoline. 2.0 TEST SERIES PROTOCOL AND MATERIALS 2.1 Test Methodology In order to validate the viability of using commercial grade heptane in lieu of unleaded, ethanol free gasoline as fuels for AFFF qualification testing under the MIL-F-24385F protocol, NAVSEA 05P directed that the fire test series be divided into two fire test phases. Phase one included fifty-four extinguishment and burnback fire tests in a 28 ft (6 ft diameter) fire pan using both full strength fresh & seawater Type-3 AFFF solutions and half strength seawater Type-3 AFFF solutions. Table 1 provides an overview of the phase one fire test matrix. Table 1 - Phase One Fire Test Matrix A gent/T est National: Full Strength/Fresh Chemguard: Full Strength/Fresh Buckeye: Full Strength/Fresh National: Full Strength/Seawater Chemguard: Full Strength/Seawater Buckeye: Full Strength/Seawater National: Half Strength/Seawater Chemguard: Half Strength/Seawater Buckeye: Half Strength/Seawater Fuel (G asoline) 3 3 3 3 3 3 3 3 3 Fuel (H eptane) 3 3 3 3 3 3 3 3 3 F ire Size ( f t 2) 28 28 28 28 28 28 28 28 28 AFFF (N ew /A ged) New New New New New New New New New Phase two testing, which included an additional forty-two fire tests addressed half-strength freshwater Type-3 AFFF solutions, half-strength seawater Type-3 AFFF solutions using aged concentrate (both in the 28 ft2 (6 ft diameter) fire pan, and full strength seawater Type-3 AFFF solutions conducted in a 50 ft (8 ft diameter) fire pan. Table 2 provides an overview of the phase two fire test matrix. 3 US00000884 Table 2 - Phase Two Fire Test Matrix A gent/T est National: Half Strength/Fresh Chemguard: Half Strength/Fresh Buckeye: Half Strength/Fresh National: Half Strength/Seawater Chemguard: Half Strength/Seawater Buckeye: Half Strength/Seawater National: Full Strength/Seawater Chemguard: Full Strength/Seawater Buckeye: Full Strength/Seawater Fuel (G asoline) 3 3 3 3 3 3 1 1 1 Fuel (H eptane) 3 3 3 3 3 3 1 1 1 F ire Size ( f t 2) 28 28 28 28 28 28 50 50 50 AFFF (N ew /A ged) New New New Aged Aged Aged New New New 2.2 Fuels All fire tests were performed using ethanol-free gasoline, obtained from a local supplier, and commercial grade heptane (Shell Chemical). Heptane has a higher flash point than gasoline. Commercial grade heptane is not isomerically pure, but is defined by a certain boiling range, and can have a variable composition depending on the supplier. One manufacturer (Shell Chemical) specifies limits of 87-105 C for the allowable boiling point range, and lists "typical values" of 93 - 99 C. Typically n-heptane is a substantial component of the mixture. The measured closed cup flash point of the lot used in testing was -9 C (manufacturer's data). Typical material properties of the Shell product from the manufacturer's data [4] (not product specifications) are shown in Table 3. Table 3 - Selected Properties (Typical Values) of Commercial Heptane used in Testing P ro p er ty Initial Boiling Point 50% Boiling Point Final Boiling Point Flash Point Vapor Pressure @ 20 C Composition: Aromatics Cycloparaffins Paraffins n-Heptane V alue 93 C 94 C 99 C <-7 C 49 Torr <0.1% 10% 90% 28% 2.3 AFFF Concentrate Formulations Used in Testing COTS samples of three Type-3 AFFF concentrates were purchased and used for phase one and phase two testing. All foams used are on the current Qualified Products List [2], Different COTS samples were used in the two series of tests. The AFFFs, lot numbers, and dates of manufacture are listed in Table 4. 4 US00000885 Table 4 - Lot numbers and dates of manufacture of AFFFs in Phase 1 and Phase 2 testing AFFF National Foam 3EM Chemguard C-301MS Buckeye BFC-3MS P hase 1 testing Lot # L11360 0923112 50285 M anufacture date Oct. 2011 Sept. 2011 Aug. 2011 P hase 2 testing Lot # L13133 0708131 120050 M anufacture date August 2013 July 2013 August 2012 3.0 PHASE ONE TEST RESULTS Phase one fire extinguishment and burnback tests were conducted for the following conditions: AFFF at nominal strength, mixed with fresh water in 28 ft fire pan AFFF at nominal strength, mixed with artificial sea water in 28 ft fire pan AFFF at one-half nominal strength, mixed with artificial sea water in 28 ft fire pan 3.1 Testsfo r AFFF Extinguishment at Full Strength, M ixed with Fresh Water in 28f t Fire Pan Extinguishment and burnback times for the tested AFFF solutions at full strength in fresh water are provided in Table 5. Table 5 - Extinguishment and 25% Burnback Times for 28 ft2, Full Strength, Fresh Water Tests Test # Fuel Type COTS M ILSPEC A FFF C oncentrate Fire O ut T im e (s) F oam A pplication Tim e B efore B u rn b ack (s) 25% Burnback T im e (s) M IL -F-24385F R equirem ent <30 90 > 360 01 Gasoline National Type 3 26 90 501 02 Gasoline National Type 3 28 90 501 03 Gasoline National Type 3 27 N/A n.d. 04 Heptane National Type 3 25 90 690 05 Heptane National Type 3 24 90 728 06 Heptane National Type 3 29 N/A n.d. 07 Gasoline Chemguard Type 3 26 90 432 08 Gasoline Chemguard Type 3 26 90 392 09 Gasoline Chemguard Type 3 26 N/A n.d. 10 Heptane Chemguard Type 3 24 90 552 11 Heptane Chemguard Type 3 25 90 529 12 Heptane Chemguard Type 3 26 N/A n.d. 13 Gasoline Buckeye Type 3 22 90 919 14 Gasoline Buckeye Type 3 22 90 704 15 Gasoline Buckeye Type 3 23 N/A n.d. 16 Heptane Buckeye Type 3 26 90 726 17 Heptane Buckeye Type 3 28 90 640 18 Heptane Buckeye Type 3 28 N/A n.d. n.d.: test not performed; N/A: not applicable 5 US00000886 2 3.2 Tests fo r AFFF Extinguishment at Full Strength, M ixed with Artificial Sea Water in a 28 f t Fire Pan Extinguishment and bumback times for the AFFF solutions tested at full strength, mixed with artificial sea water are provided in Table 6.2 Table 6 - Extinguishment and 25% Bumback Times for 28 ft2, Full Strength, Artificial Sea Water Tests Test # Fuel Type COTS M ILSPEC A FFF C oncentrate Fire O ut T im e (s) F oam A pplication T im e (s) 25% Bum back T im e (s) M IL -F-24385F R equirem ent 19 Gasoline National Type 3 20 Gasoline National Type 3 21 Gasoline National Type 3 22 Heptane National Type 3 23 Heptane National Type 3 24 Heptane National Type 3 25 Gasoline Chemguard Type 3 26 Gasoline Chemguard Type 3 27 Gasoline Chemguard Type 3 28 Heptane Chemgurad Type-3 29 Heptane Chemguard Type-3 30 Heptane Chemguard Type-3 31 Gasoline 32 Gasoline Buckeye Type-3 Buckeye Type-3 33 Gasoline Buckeye Type-3 34 Heptane Buckeye Type-3 35 Heptane Buckeye Type-3 36 Heptane Buckeye Type-3 n.d.: test not performed; N/A: not applicable <30 27 31 26 33 30 30 30 29 29 28 27 26 27 27 24 36 30 30 90 > 360 90 579 90 438 N/A n.d. 90 671 90 667 N/A n.d. 90 492 90 521 N/A n.d. 90 706 90 598 N/A n.d. 90 575 90 572 N/A n.d. 90 662 90 646 N/A n.d. 2 3.3 Tests fo r AFFF Extinguishment at H a lf Strength, M ixed with Artificial Sea Water in a 28 f t Fire Pan Fire extinguishment and burnback times for the AFFF solutions tested at half strength, mixed with artificial sea water are provided in Table 7. 6 US00000887 Table 7 - Extinguishment and 25% Bumback Times for 28 ft2, Half Strength with artificial Sea Water Tests Test # Fuel Type COTS M ILSPEC A FFF C oncentrate Fire O ut T im e (s) F oam A pplication T im e (s) 25% Burnback T im e (s) M IL -F-24385F R equirem ent 37 Gasoline National Type 3 38 Gasoline National Type 3 39 Gasoline National Type 3 40 Heptane National Type 3 41 Heptane National Type 3 42 Heptane National Type 3 43 Gasoline Chemguard Type 3 44 Gasoline Chemguard Type 3 45 Gasoline Chemguard Type 3 46 Heptane Chemguard Type 3 47 Heptane Chemguard Type 3 48 Heptane Chemguard Type 3 49 Gasoline 50 Gasoline Buckeye Type 3 Buckeye Type 3 51 Gasoline Buckeye Type 3 52 Heptane Buckeye Type 3 53 Heptane Buckeye Type 3 54 Heptane Buckeye Type 3 n.d.: test not performed; N/A: not applicable <45 42 43 35 41 47 45 48 36 37 48 40 36 38 31 31 30 45 28 90 > 300 90 522 90 461 N/A n.d. 90 681 90 664 N/A n.d. 90 453 90 455 N/A n.d. 90 655 90 508 N/A n.d. 90 422 90 637 N/A n.d. 90 559 90 590 N/A n.d. 4.0 PHASE TWO TEST RESULTS Phase two fire extinguishment and burnback tests were conducted for the following conditions: AFFF one-half nominal strength using aged concentrate, mixed with artificial sea water in a 28 ft2 fire pan. 2 AFFF one-half nominal strength, mixed with fresh water in a 28 ft fire pan. AFFF at nominal strength, mixed with artificial sea water in a 50 ft fire pan. 4.1 Tests fo r AFFF Extinguishment at H a lf Strength using Aged Concentrate M ixed with Artificial Sea Water in a 28f t 2Fire Pan Extinguishment and burnback times for the tested AFFF solutions at half strength with aged concentrate in artificial sea water are provided in Table 8. 7 US00000888 Table 8 - Extinguishment and 25% Bumback Times for 28 ft2, Aged Concentrate, Half Strength, Artificial Sea Water Tests Test # Fuel Type COTS M ILSPEC A FFF C oncentrate M IL -F-24385F R equirem ent 01 Gasoline National Type 3 02 Gasoline National Type 3 03 Gasoline National Type 3 04 Heptane National Type 3 05 Heptane National Type 3 06 Heptane National Type 3 07 Gasoline Chemguard Type 3 08 Gasoline Chemguard Type 3 09 Gasoline Chemguard Type 3 10 Heptane Chemguard Type 3 11 Heptane Chemguard Type 3 12 Heptane Chemguard Type 3 13 Gasoline 14 Gasoline 15 Gasoline Buckeye Type 3 Buckeye Type 3 Buckeye Type 3 16 Heptane Buckeye Type 3 17 Heptane 18 Heptane Buckeye Type 3 Buckeye Type 3 n.d.: test not performed; N/A: not applicable Fire O ut T im e (s) <45 33 30 28 50 47 48 34 48 55 59 52 62 28 25 27 34 29 31 F oam A pplication T im e (s) 90 90 N/A N/A 90 N/A N/A 90 N/A N/A 90 N/A N/A 90 N/A N/A 90 N/A N/A 25% Bum back T im e (s) >300 610 n.d. n.d. 720 n.d. n.d. 545 n.d. n.d. 714 n.d. n.d. 360 n.d. n.d. 519 n.d. n.d. 2 4.2 Tests fo r AFFF Extinguishment at H a lf Strength, M ixed with Fresh Water in a 28 f t Fire Pan Fire extinguishment and bumback times for AFFF solutions tested at half strength, mixed with fresh water are provided in Table 9. 8 US00000889 Table 9 - Extinguishment and 25% Bumback Times for 28 ft2, Half Strength, Fresh Water Tests Test # Fuel Type COTS M il,SPEC A FFF C oncentrate Fire O ut T im e (s) F oam A pplication T im e (s) 25% Bum back T im e (s) M IL -F-24385F R equirem ent <45 90 > 300 19 Gasoline National Type 3 28 90 412 20 Gasoline National Type 3 28 N/A n.d. 21 Gasoline National Type 3 30 N/A n.d. 22 Heptane National Type 3 31 90 739 23 Heptane National Type 3 31 N/A n.d. 24 Heptane National Type 3 28 N/A n.d. 25 Gasoline Chemguard Type 3 50 90 482 26 Gasoline Chemguard Type 3 43 N/A n.d. 27 Gasoline Chemguard Type 3 5" N/A n.d. 28 Heptane Chemguard Type 3 62 90 553 29 Heptane Chemguard Type 3 60 N/A n.d. 30 Heptane Chemguard Type 3 65 N/A n.d. 31 Gasoline Buckeye Type 3 35 90 481 32 Gasoline Buckeye Type 3 35 N/A n.d. 33 Gasoline Buckeye Type 3 61 N/A n.d. 34 Heptane Buckeye Type 3 31 90 726 35 Heptane Buckeye Type 3 37 N/A n.d. 36 Heptane Buckeye Type 3 38 N/A n.d. n.d.: test not performed; N/A: not applicable 2 4.3 Tests fo r AFFF Extinguishment at fu ll Strength, M ixed with Artificial Sea Water in a 50 f t Fire Pan Fire extinguishment and summation times for AFFF solutions tested at full strength, mixed with artificial sea water are provided in Table 10. 9 US00000890 Table 10 - Extinguishment and Summation Times for 50 ft2, Full Strength, Artificial Sea Water Tests Test # 37 38 39 40 41 42 Fuel Type COTS M ILSPEC A FFF C oncentrate M IL -F -24385F requirem ent Gasoline National Type 3 Heptane National Type 3 Gasoline Heptane Chemguard Type 3 Chemguard Type 3 Gasoline Heptane Buckeye Type 3 Buckeye Type 3 F ire O ut T im e (s) <50 36 50 50 39 38 40 40 Second Sum m ation A pplication 320 (Sec) 365 363 354 359 364 359 5.0 ANALYSIS & DISCUSSION OF TEST RESULTS 5.1 Extinguishment Performance There does not appear to be a clear trend in extinguishment time between gasoline and heptane fuels that holds for all AFFFs and all test conditions. In general, the extinguishment times were slightly longer for heptane (particularly in the half strength tests), but exceptions to this trend are observed. Heptane does have a lower surface tension in comparison to gasoline and therefore film formation is more difficult on heptane [5], Because of this trend it may be appropriate to extend the required fire out time for the half strength tests to 50 seconds instead of the 45 seconds currently required for gasoline fuel. In the full strength tests, all of the AFFFs tested were able to extinguish the fire within 30 seconds in at least two out of three replicates using both fresh water and artificial seawater, on both gasoline and heptane fires. Therefore, there does not appear to be a reason to alter the 30 second extinguishment requirement for a change to heptane test fuel. In the 50 ft2 tests, all three AFFFs tested passed the fire out time and the summation requirements on both fuels, with no clear trends observed between heptane and gasoline. It does not appear necessary to change the requirements for the 50 ft2 test from their current values. 5.2 Burnback Performance As noted previously in preliminary testing on heptane conducted in 2010, heptane fuel tends to produce far longer burnback times than gasoline [6], As an example, in Table 9 the burnback times for the three AFFFs averaged over three minutes longer on heptane than on gasoline. Because the burnback test is much easier to pass on heptane, an AFFF would still be able to pass the test while providing burnback protection that is not as good. In Reference 6 it was found that reduction of the total foam application time to 60 seconds from the current 90 seconds produces burnback times on heptane comparable to the current values using gasoline, resulting in a comparably challenging test. 6.0 RECOMMENDATIONS 6.1 Changes to Fire Test Protocol We recommend changing the test fuel for AFFF MILSPEC qualification to commercial grade heptane of the boiling point range used in the present test series (87-105 C specification, 93 - 99 10 US00000891 C typical). The present test series demonstrates that heptane presents a comparable challenge to AFFF performance as gasoline, and use of heptane avoids the difficulty in obtaining ethanol-free gasoline, as well as seasonal and location-dependent variations in fuel properties. The recommended changes listed below for fire out time and burnback procedure are intended to make a qualification test on heptane as comparable as possible to the current MIL-F-24385F on gasoline. We recommend increasing the allowable fire out time for the half strength tests to 50 seconds from the current 45 seconds. We do not recommend changing the allowable fire out time for the full strength 28 ft2 tests (currently 30 seconds), nor for the 50 ft2tests (currently 50 seconds). For the burnback tests, we recommend reducing the total foam application time from the current 90 seconds to 75 seconds. We do not recommend changing the 25% burnback times from their current values. 6.2 Other Changes to MIL-F-24385F In addition to the change of the test fuel and other modifications above, we suggest the following changes to other aspects of the qualification test for consideration. 6.2.1 Fish Toxicity Testing MI1.-F-24385F specifies AFFF concentrate fish toxicity testing on Fundulus heteroclitus, commonly known as the killifish or mummichog. This species is found in streams and estuaries on the east coast of the U.S. and Canada, and can live in both salt and fresh water. Significantly, it is known to be an extremely hardy species which can survive in wide ranges of temperature, salinity, turbidity, and oxygen concentration, as well as in environments with high levels of pollution [7], O f special relevance to AFFF toxicity testing is the ability of this fish to survive low oxygen levels, as one of the toxicity mechanisms of AFFF concentrate is thought to be adherence of the surfactants in AFFF to the fishes' gills, causing suffocation. Because of the ability of Fundulus heteroclitus to survive in harsh conditions, it appears not to be an appropriate indicator species, as other fish species in a given environment may have significantly lower LC50 concentrations for AFFF concentrate. Furthermore, Fundulus heteroclitus is not commonly used in toxicity testing; for toxicity testing of non-MILSPEC AFFF concentrates; most data are recorded using either rainbow trout (Oncorhynchus mykiss) or fathead minnow (.Pimephales promelas). An EPA guideline on fish toxicity testing [8] recommends rainbow trout and bluegill sunfish (Lepomis macrochirus) as indicator species, respectively, for cold and warm freshwater environments "since they are sensitive indicator species and a large data base which characterizes the response to environmental contaminants is available." For species which can live in saltwater environments, Reference [9] recommends the Atlantic silverside (Menidia menidia) or the sheepshead minnow (Cyprinodon variegatus); however the latter species is also known to be able to survive oxygen depletion, so may not be an appropriate species for AFFF testing. Tyndall AFB has conducted toxicity testing on alternative fire suppressant agents on the fathead minnow (Pimephales promelas), using Type 3 MILSPEC AFFF as a baseline compound [10], In different series of tests Chemguard and Ansul AFFFs have been used as baseline compounds. In both cases, the LC50 for these AFFFs on Pimephales promelas was greater than the 500 ppm requirement of MIL-F-24385F. In the case of the Ansul AFFF, the measured LC50 of 522 ppm was only slightly greater than 500 ppm. 11 US00000892 We recommend that the fathead minnow (Pimephales promelas) be used as the test species for AFFF fish toxicity, with minimum LC50 concentrations of 400 ppm and 800 ppm for Type 3 and Type 6 concentrate, respectively. 6.2.2 Halide Concentrations Test MIL-F-24385F currently includes a test for halide concentration following the procedure of ATSM D-1821. We recommend removing this test for the following reasons: 1. The test is not general for all halides; in particular, it does not include fluorides 2. The D-1821 standard is obsolete, and 3. The rationale for determining halide concentration in the AFFF concentrate is presumably to ensure the concentrate is not too corrosive to metal surfaces; however, MIL-F-24385F already includes pitting and corrosion tests on various metals of construction used in shipboard AFFF systems. Therefore, any AFFF which produced excessive corrosion would be identified in the corrosion tests, rendering the halide test redundant. 6.2.2 COD/BOD We recommend leaving the Chemical Oxygen Demand test unchanged, as this measured the amount of organic material present in AFFF, which may cause oxygen depletion in case of spillage into a body of water. We recommend deleting the Biological Oxygen Demand test. This test tends to give poor reproducibility of results between analytical laboratories, and sometimes an impossible BOD/COD ratio greater than one is found. Most of the organic material in AFFF consists of glycol ether solvents, and the biological consumption rate of these compounds, which are not typical food sources in the environment, depends on the biota added to the solution for the test. Furthermore, although the BOD/COD ratio is intended to assess biodegradability of the material, the components of AFFF which are not biodegradable are the fluorosurfactants, which are a small proportion of the material, but extremely persistent in the environment. 6.2.4 Refractometry Because the purpose of the index of refraction requirement is to allow shipboard determination of proportioning accuracy via refractometry, we propose changing the requirement from a fixed refractive index value to following the procedure specified on the Shipboard Maintenance Requirement Card (MRC), which specifies a field procedure for shipboard determination of AFFF proportioning by refractometry [10], In accordance with Table 2 of reference 10, the proportion of AFFF concentrate in an AFFF solution is calculated by the following formula, which assumes a linear interpolation of refractive index between pure water and pure concentrate: A = R s (index of AFFF solution) - Rw(index of artificial seawater) B = Rt (index of AFFF concentrate) - Rw(index of artificial seawater) % foam concentration = 100 x A B 12 US00000893 The acceptable range for shipboard and/or field foam concentration analysis specified in reference 11 is 5% to 8% for Type 6 AFFF solutions and 2.5% to 4% for Type 3 AFFF solutions. This recommendation is also consistent with a previous finding noted in reference 11. 6.2.5 Repeatability o fPassing Fire Extinguishment and Burnback Times Currently, the MILSPEC requires specified fire extinguishment times for various test conditions. However, there is no guidance for the number of tests allowed to achieve a passing time. In testing, outlier values for fire out time are obtained, due to factors in the test conditions other than the foam itself. However, an AFFF should not be given a passing grade due to a fortuitous value obtained on a single test which is not repeatable. Therefore, we recommend that the requisite fire extinguishment and burnback times must be obtained on two consecutive tests for the result to be considered a "pass". 6.3 Other AFFF Issues The following topics are not formally related to the proposed change in AFFF test fuel or other modifications to the MILSPEC test. They are, however, important for assuring adequate AFFF fire protection in DoD which have come to our attention during recent AFFF testing. 6.3.1 Packaging It was noted that the specified color scheme for AFFF packaging (white letters on a green background for Type 3, white letters on a blue background for Type 6) was not followed for any of the Type 3 AFFFs tested. All containers were white, and the different brands used three different colors of lettering: Buckeye and Chemguard used green lettering, National used blue lettering, and Ansul used red lettering. While these samples were purchased commercially rather than being obtained through the DoD supply, commercially-obtained samples can find their way onto Navy ships through shipyards or other contractors. 6.3.2 ShelfLife Based on previous AFFF testing conducted at NRL, in which AFFF remaining from the original qualification tests and subsequently stored for a long period (typically 20 years or more) failed to perform well, we recommend instituting a maximum shelf life requirement for AFFF concentrate of fifteen years. 7.0 REFERENCES 1. MIL-F-24385F, Fire Extinguishing Agent, Aqueous Film-Forming Foam (AFFF), Liquid Concentrate, for Fresh and SeaWater, Naval Sea Systems Command, 7 January 1992. 2. "Qualified Products List: Products Qualified Under Military Specification MIL-F-24385 (Fire Extinguishing Agent, Aqueous Film-Forming Foam (AFFF), Liquid Concentrate, for Fresh and Sea Water)" QPL-24385-35, Naval Sea Systems Command, 3 January 2007. 3. Underwriters Laboratory (UL) Standard 162, "Fire Safety for Foam Equipment and Liquid Concentrates," l x Edition, Northbrook IL, 30 March 1994. 4. Shell Chemical Company, Data Sheet for SHELLSOL Heptane, 02 July 2003 http://www.scdvnamiccontent.shell.com/Files/specialboilingpointsolvents heptane ameri cas.pdf 13 US00000894 5. Leonard, J.T., and Burnett, "Suppression of Evaporation of Hydrocarbon Liquids and Fuels by Films Containing Aqueous File Forming Foam (AFFF) Concentrate FC-196, NRL Report 7842, 31 December 1974. 6. Williams, B.A., Murray, T., Butterworth, C., Whitehurst, C.L., Farley, J.P., Sheinson, R.S., "Comparison of Commercial Grade Heptane with Unleaded, Ethanol-Free Gasoline as Fuels of AFFF Qualification Testing under MIL-F-24385F Protocol," NRL Ltr Rpt Ser 6180/0041, 05 April 2011. 7. Weis, J.S., "Tolerance to Environmental Contaminants in the Mummichog, Fundulus Heteroclitus," Human and Ecological Risk Assessment; 8 (2002); 933-953. 8. U.S. Environmental Protection Agency, Ecological Effects Test Guidelines; OPPTS 850.1075: Fish Acute Toxicity Test, Freshwater and Marine (EPA 712-C-96-118; April 1996). 9. Kiel, J.C., Kalberer, J.L. and Rochefort, M.M. "Aquatic Toxicity Screening of Fire Fighting Agents," AFRL-ML-TY-TR-2005-4580 (2004). 10. Maintenance Requirement Card (MRC), OPNAV 4790/85 (Rev. 9-97). 11. Farley, J.P., Williams, B.A., Whitehurst, C.L., Murray, T., Fleming, J.W., Ouellette, R., Blevins, J., "Results of Follow-up MIL-F-24385F Qualification Testing of Fire-Ade AFFF Type 3/6 Concentrate," NRL Ltr Rpt 6180/0069, 07 April 2011. 14 US00000895