United States Patent [I~I I1 4,406,797 Altman et al. [45] Sep. 27, 1983 - ______-___

[54] FIRE EXTINGUISHANT MATER1AI.S 1561 References Cited U.S. PATENT DOCUMENTS [75] Inventors: Robert I.. Altman, Berkeley, Calif.; Ludwig A. Mayer; Alan C. Ling, both 4,149,976 4/1979 Keuillon et al...... 252/5 4,194,979 3/19RO Gottschall ...... 252/5 of San Jose, Calif. Primary Examiner-Leland A. Sebastian [73] Assignee: The United States of America as ,+Im~rncy,Agenl, or Firm-Darrell G. Brekke; John R. represented by the Administrator of Manning the National Aeronautics and Space [571 ABSTRACI Administration, Washington, D.C. Fire extinguishant composition comprising a mixture of a finely divided aluminum compound and , [21] Appl. No.: 317,977 stannous or plumbous halide. Aluminum compound may be alumirium hydroxide, alumina or boehmite but [22] Filed: Nov. 3, 1981 preferably it is an alkali metal dawsonite. The metal halide may be an alkali metal, e.g. iodide, [5 11 Int. el.’ ...... A62D 1/00 bromide or chloride or stannous or plumbous iodide, [52] US. CI...... 252/5; 169/47; bromide or chloride. i\ preferred. 252/2 [58] Field of Search ...... 169/47; 252/2, 5 11 Claims, No Drawings 4,406,797-. 1 2 ferred to a cylindrical open-top vessel made of alumi- FIRE EXTINGUISHANT MATERIALS num or other inert metal. The vessel is placed into a high pressure reactor. The reactor is flushed with gase- ORIGIN OF THE INVENTION ous carbon dioxide and pressurized with the same gas to The invention described herein was made in the per- 5 a level within the range of 120 to 360 psig. The reactor formance of work under a NASA contract and is sub- is then heated as quickly as possible to a temperature ject to the provisions of Section 305 of the National within the range of 150" to 250" C., and it is maintained Aeronautics and Space Act of 1958, Public Law 85-568 at that temperature for a period of about 1 to 6 hours. (72 Stat. 435; 42 USC 2457). When potassium hydrogencarbonate is used, the calci- 10 nation is preferably carried out at a temperature within TECHNICAL FIELD the range of 240" to 250" C. for about 4 to 6 hours under This invention relates to compositions of matter a carbon dioxide pressure of 230 to 250 psig. After cool- which are useful for extinguishing fires, more particu- ing and depressurization, the product is dried in a vac- larly fires on hot metal surfaces caused by leakage of uum oven at 50" C. hydrocarbon fuels such as jet fuels, and it relates also to 15 The proportions of aluminum ingredient ( or ox- the use of such compositions for such purposes. ide) and of the metal halide ingredient may vary from 25 to 99% of aluminum ingredients to 75 to 1% of metal BACKGROUND ART halide. (Percentages throughout are by weight.) In Altman US. patent application Ser. No. 178,192 In the static test a hemicylindrical stainless steel filed Aug. 14, 1980, now U.S. Pat. No. 4,356,157, enti- 20 trough was employed. The under side of the trough was tled "Synthesis of Dawsonites", a method of synthesiz- heated electrically, the temperature being measured by ing dawsonites [MA 1(OH)2C03 wherein M represents means of a thermocouple. Jet fuel (the type known as an alkali metal or the ammonium radical] is described, JP-4) was caused to drip continuously onto the upper such dawsonites having utility for extinguishing fires, surface of the trough. When a flame had developed and 25 more particularly fires on hot metal surfaces caused by had reached a more or less steady state the extinguish- leakage of hydrocarbon fuels such as jet fuels. Such fires ant material, in the form of a fine powder, was applied occur, for example, in the nacelles of jet aircraft and it to the flame. Meanwhile input of heat and fuel contin- is advantageous to be able to pour a powdery, solid ued. Note was taken of the time before the flame rekin- mixture of fire extinguishing material over the hot en- dled. 30 gine surface. It is important that the fire extinguishing In the flow test similar fuel was sprayed into a test effect have a sufficient duration to allow time for reme- section of a duct to simulate a leakage of fuel. The test dial action to be taken. section was heated externally by a propane flame. Air 11 is an object of the present invention to provide was caused to flow through the test section to simulate improvements in dawsonites and in other aluminum compounds such as aluminum hydroxide, boehmite and 35 in flight conditions. Again, as in the static test, the extin- alumina for such purposes. guishant material was applied to the test section when the flame had reached a more or less steady state. As in DISCLOSURE OF THE INVENTION the static test note was taken of the time for the flame to The above and other objects of the invention are rekindle. accomplished by providing a mixture of such an alumi- 40 Results with the static test are set forth in Tables I num compound, preferably dawsonite and most prefer- and I1 below and results with the flow test are set forth ably potassium or dawsonite, with a metal hal- in Table 111. ide, more particularly potassium iodide. TABLE 1 REIGNITION DELAY DETAILED DESCRIPTION OF THE 45 INVENTION INGREDIENTS TIME, SECONDS 750" C 900°C In accordance with the present invention the fire (1) A~(OH)J 100?30 3t2 extinguishant properties of dawsonites (sodium and (2) AlOOH 48 t 35 NONE potassium dawsonites) and of aluminum hydroxide, (3) AI203 28 t 12 NONE alumina and boehmite are greatly improved by incorpo- 5u (4) Al(OH)) f Sf112(7% I) 204+20 811 (5) AI(OH)j + KI (8% I) 233 t 56 - rating therein a substantial amount of metal halide. (6)AI(OH)1 i KI (7% 1) 72 L 3 811 Among halides which may be so used are potassium (7) AlOOH + K1 (7% It 131 I7 15 t 4 chloride, , potassium iodide; their (8)AI203 + KI (7% 1) > 900 50 2z 12 sodium analogs, namely , bromide and 700" c 900" c Sn12 (68% I) 380 * 80 2 2 2 iodide; also tin and lead such as tin chlorides, bro- 55 KI (76% I) > 900 252 mides and iodides, preferably stannous salts; and also NOTE lead halides such as lead chloride, bromide and iodide, Mixtures (4) dnd (51 were mechanical mixture, Mixture, (6) (7) and IR) *ere preferably the plumbous halides. prehcatcd As stated, the preferred aluminum compound is an alkali metal dawsonite, preferably potassium dawsonite. 60 TABLE 11 This ingredient is preferably prepared by an anhydrous REIGNITION DELAY method such as that described in the above mentioned INGREDIENTS TIME. SECONDS copending application. Briefly stated such method of preparation may be as follows: -700°C 8MJ'C 900°C (I)SnI2(68%) 380 '-c 80 2i2 Equimolar quantities of aluminum hydroxide, e.g. 65 (2) K1(76% I) >m 16i6 222 gibbsite, and an alkali metal hydrogen carbonate in the (3) Nal(854 1) m-+m 3.c 2 form of a dry, ground powder with a particle size 750" c 900' c smaller than 90 pm, are intimately mixed and trans- (4) N~N(OH)~COI 296 i 50 29 t 5 6 -C 3 4,406,797 1 3 4 TABLE 11-continued In preparing the mixtures of the invention a simple mechanical mixing is sufficient. It is preferred that each REIGNITION DELAY INGREDIENTS TIME, SECONDS of the ingredients be in a finely divided state, for exam- ple about 250 to 350 mesh. Inasmuch as some of the (5) KAI(OH)ZCO~ 153 15 IO 4 f f 5 iodides are somewhat hygroscopic, it is preferred that (6) KAl(OH)rCO, + Sn12(6% I) 520 f 52 51 h 3 (7) KAI(OH)2CO) + Sn12(6% I) 419 * 51 50 f 2 the iodide, or the mixture of iodide and aluminum com- (8) KAI(OH)2CO3 + KI(7S I) 500 t 90 13 -+ 4 pound, be heated to drive off moisture and that the (9) KAI(OH),COi + KU7% I) >900 50 f 14 mixture be kept in a reasonably airtight container. The principal disadvantage resulting from the presence of NOTE: 10 moisture is that the product does not pour as readily. It Mixtures (6) and (8) were mechanical mixtures. Mixlures (7) and (9) were preheated. is important in extinguishing a fire on a heated surface, such as a fire caused by leakage of jet fuel in a nacelle, TABLE 111 that the extinguishant mixture be readily pourable so REIGNITION that it will spread rapidly and evenly over the burning DELAY TIME, sec. 15 surface. AT VARIOUS AIRFLOWS, mps It is therefore apparent that new and useful fire extin- DRY CHEMICALS GRAMS 6 36 guishant conipositions have been provided. We claim: (I) KCl (PYROCHEM) 30 20 05 20 stantial proportions each of (a) an aluminum compound (3) KD + KCI (32%) 10-20 2 > 20 selected from the group consisting of AI(OH3), AIOOH (4) KI 40 20 lected from the group consisting of alkali metal, tin and (6) KD + K1 (5%) 20 I 20 - lead halides. (7) KD + KI (9%) 15 20 (a) and (b) are present in proportions of about 25 to 99 (9) KD + Sn12(5%) 15 >20 > 20 percent of (a) and about 75 to 1 percent of (b). (10) KD + Snl2(10S0) I5 >20 > 20 (11) KD + Snl2(20%) IO >20 > 20 3. The composition of claim 2 wherein component (a) NO? E is an alkali metal dawsonite. Minturer (6) to (I I)were preheated 30 4. The composition of claim 2 wherein component (b) is an alkali metal halide. Referring now to these tables and first to Table I, the 5. The composition of claim 2 wherein component (a) more significant results are those set forth in the column is an alkali metal dawsonite and component (b) is an headed 900" C., that being the temperature to which the alkali metal halide. test trough was heated. As will be seen, of the three 35 6. The composition of claim 1 wherein component (a) aluminum compounds employed by themselves two is potassium or sodium dawsonite, component (b) is resulted in no delay time in rekindling and one (alumi- potassium iodide, and the two are present in the porpor- num hydroxide) provided a delay time of only 3+2 tions of approximately 95 to 80 percent of the dawsonite seconds. Results with stannous iodide and potassium and 50 to 20 percent of potassium iodide. iodide were similar. On the other hand, in each of the 40 7. A method of extinguishing fires arising from leak- mixtures very significant improvement was noted. Thus age of fuel onto a hot solid surface, said method com- in the case of aluminum hydroxide plus stannous iodide prising applying to the hot, flaming surface a powdery (7 percent ) the delay time was 8+ 1 seconds; in mixture of (a) an aluminum compound selected from the the case of the boehmite-potassium iodide mixture, the group consisting of aluminum hydroxide, boehmite, delay time was 15f4 seconds; and in the case of the 45 alumina and an alkali metal dawsonite, and (b) a metal alumina-potassium iodide mixture the delay time was halide. 50% 12 seconds. 8. The method of claim 7 wherein components (a) and Referring now to Table I1 potassium dawsonite was (b) are present in the mixture in the proportions of about the chosen aluminum compound. It is apparent that 25 to 99 percent of (a) and about 75 to 1 percent of (b). mixtures of potassium dawsonite with stannous iodide so 9. The method of claim 7 wherein component (a) is an and with potassium iodide performed much better than alkali metal dawsonite. either the dawsonite alone or the iodide alone. 10. The method of claim 7 wherein component (b) is Referring now to Table 111, it is apparent, especially an alkali metal iodide. at higher rates of air flow and considering the quantities 11. The method of claim 7 wherein the mixture is a of extinguishant material which were used, that mix- 55 mixture of about 80 to 95 percent of an alkali metal tures of potassium dawsonite with a potassium halide or dawsonite and about 20 to 5 percent of potassium io- stannous iodide performed much better than the indi- dide. vidual components. *****

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