Fire extinguishant composition comprising a mixture of a finely divided aluminum compound and alkali metal, stannous or plumbous halide is provided. Aluminum compound may be aluminum hydroxide, alumina or boehmite but preferably it is an alkali metal dawsonite. The metal halide may be an alkali metal, e.g. potassium iodide, bromide or chloride or stannous or plumbous iodide, bromide or chloride. Potassium iodide is preferred

Altman, R. L.

Ling, A. C.

Mayer, L. A.

English

NASA Technical Reports Server

United States Patent [ I ~ I  
_________ 
Altman et al. 
- 
[54] FIRE EXTINGUISHANT MATER1AI.S 
[75] Inventors: Robert I.. Altman, Berkeley, Calif.; 
Ludwig A. Mayer; Alan C. Ling, both 
of San Jose, Calif. 
[73] Assignee: The United States of America as 
represented by the Administrator of 
the National Aeronautics and Space 
Administration, Washington, D.C. 
[21] Appl. No.:  317,977 
[22] Filed: Nov. 3, 1981 
[5  11 
[52] 
[ 5 8 ]  
Int. el.’ ............................................... A62D 1/00 
US. CI. .......................................... 252/5; 169/47; 
252/2 
Field of Search .......................... 169/47; 252/2, 5 
I 1  4,406,797 
[45] Sep. 27, 1983 __-___ 
1561 References Cited 
U.S. PATENT DOCUMENTS 
4,149,976 4/1979 Keuillon et al. ....................... 2 5 2 / 5  
4,194,979 3/19RO Gottschall ............................ 2 5 2 / 5  
Primary Examiner-Leland A. Sebastian 
,+Im~rncy, Agenl, or Firm-Darrell G. Brekke; J o h n  R.  
Manning 
[571 ABSTRACI 
Fire extinguishant composition comprising a mixture of 
a finely divided aluminum compound and alkali metal, 
stannous or plumbous halide. Aluminum compound 
may be alumirium hydroxide, alumina or boehmite but 
preferably i t  is an alkali metal dawsonite. The metal 
halide may be an alkali metal, e.g. potassium iodide, 
bromide or chloride or  stannous or  plumbous iodide, 
bromide or chloride. Potassium iodide i\ preferred. 
11 Claims, No Drawings 
https://ntrs.nasa.gov/search.jsp?R=19830027847 2020-03-22T01:37:48+00:00Z
1 
FIRE EXTINGUISHANT MATERIALS 
4,406,797 
ORIGIN OF T H E  INVENTION 
The invention described herein was made in the per- 
formance of work under a NASA contract and is sub- 
ject to the provisions of Section 305 of the National 
Aeronautics and Space Act of 1958, Public Law 85-568 
(72 Stat. 435; 42 USC 2457). 
TECHNICAL FIELD 
This invention relates to compositions of matter 
which are useful for extinguishing fires, more particu- 
larly fires on hot metal surfaces caused by leakage of 
hydrocarbon fuels such as jet fuels, and it relates also to 
the use of such compositions for such purposes. 
BACKGROUND ART 
In Altman US. patent application Ser. No. 178,192 
filed Aug. 14, 1980, now U.S. Pat. No. 4,356,157, enti- 
tled "Synthesis of Dawsonites", a method of synthesiz- 
ing dawsonites [MA 1(OH)2C03 wherein M represents 
an alkali metal or the ammonium radical] is described, 
such dawsonites having utility for extinguishing fires, 
more particularly fires on hot metal surfaces caused by 
leakage of hydrocarbon fuels such as jet fuels. Such fires 
occur, for example, in the nacelles of jet aircraft and it 
is advantageous to be able to pour a powdery, solid 
mixture of fire extinguishing material over the hot en- 
gine surface. It is important that the fire extinguishing 
effect have a sufficient duration to allow time for reme- 
dial action to be taken. 
11 is an object of the present invention to provide 
improvements in  dawsonites and in other aluminum 
compounds such as aluminum hydroxide, boehmite and 
alumina for such purposes. 
DISCLOSURE OF T H E  INVENTION 
The above and other objects of the invention are 
accomplished by providing a mixture of such an alumi- 
num compound, preferably dawsonite and most prefer- 
ably potassium or sodium dawsonite, with a metal hal- 
ide, more particularly potassium iodide. 
DETAILED DESCRIPTION OF T H E  
INVENTION 
In accordance with the present invention the fire 
extinguishant properties of dawsonites (sodium and 
potassium dawsonites) and of aluminum hydroxide, 
alumina and boehmite are greatly improved by incorpo- 
rating therein a substantial amount of metal halide. 
Among halides which may be so used are potassium 
chloride, potassium bromide, potassium iodide; their 
sodium analogs, namely sodium chloride, bromide and 
iodide; also tin and lead salts such as tin chlorides, bro- 
mides and iodides, preferably stannous salts; and also 
lead halides such as lead chloride, bromide and iodide, 
preferably the plumbous halides. 
As stated, the preferred aluminum compound is an 
alkali metal dawsonite, preferably potassium dawsonite. 
This ingredient is preferably prepared by an anhydrous 
method such as that described in the above mentioned 
copending application. Briefly stated such method of 
preparation may be as follows: 
Equimolar quantities of aluminum hydroxide, e.g. 
gibbsite, and an alkali metal hydrogen carbonate in the 
form of a dry, ground powder with a particle size 
smaller than 90 pm, are intimately mixed and trans- 
5 
10 
15 
20 
25 
30 
35 
40 
45 
5u 
55 
60 
65 
- .  
2 
ferred to a cylindrical open-top vessel made of alumi- 
num or other inert metal. The vessel is placed into a 
high pressure reactor. The  reactor is flushed with gase- 
ous carbon dioxide and pressurized with the same gas to 
a level within the range of 120 to 360 psig. The  reactor 
is then heated as quickly as possible to a temperature 
within the range of 150" to 250" C., and it is maintained 
at that temperature for a period of about 1 to 6 hours. 
When potassium hydrogencarbonate is used, the calci- 
nation is preferably carried out at a temperature within 
the range of 240" to 250" C. for about 4 to 6 hours under 
a carbon dioxide pressure of 230 to 250 psig. After cool- 
ing and depressurization, the product is dried in a vac- 
uum oven at 50" C. 
The proportions of aluminum ingredient (salt or ox- 
ide) and of the metal halide ingredient may vary from 25 
to 99% of aluminum ingredients to 75 to 1 %  of metal 
halide. (Percentages throughout are by weight.) 
In the static test a hemicylindrical stainless steel 
trough was employed. The under side of the trough was 
heated electrically, the temperature being measured by 
means of a thermocouple. Jet fuel (the type known as 
JP-4) was caused to drip continuously onto the upper 
surface of the trough. When a flame had developed and 
had reached a more or less steady state the extinguish- 
ant material, in the form of a fine powder, was applied 
to the flame. Meanwhile input of heat and fuel contin- 
ued. Note was taken of the time before the flame rekin- 
dled. 
In the flow test similar fuel was sprayed into a test 
section of a duct to simulate a leakage of fuel. The  test 
section was heated externally by a propane flame. Air 
was caused to flow through the test section to simulate 
in flight conditions. Again, as in the static test, the extin- 
guishant material was applied to the test section when 
the flame had reached a more or less steady state. As in 
the static test note was taken of the time for the flame to 
rekindle. 
Results with the static test are set forth in Tables I 
and I1 below and results with the flow test are set forth 
in Table 111. 
TABLE 1 
REIGNITION DELAY 
INGREDIENTS TIME, SECONDS 
750" C 900°C 
( 1 )  A~(OH)J 1 0 0 ? 3 0  3 t 2  
(2) AlOOH 48 t 35 NONE 
( 3 )  AI203 28 t 12 NONE 
(4) Al(OH)) f Sf112(7% I )  2 0 4 + 2 0  8 1 1  
( 5 )  AI(OH)j + KI (8% I )  233 t 56 - 
( 6 )  AI(OH)1 i K I  (7% 1) 72 L 3 8 1 1  
(7) AlOOH + K1 (7% It  131 I 7  15 t 4 
( 8 )  AI203 + K I  (7% 1) > 900 50 2z 12 
700" c 900" c 
Sn12 (68% I) 380 * 80 2 2 2 
KI (76% I )  > 900 2 5 2  
NOTE 
Mixtures (4) dnd (51 were mechanical mixture, Mixture, ( 6 )  (7) and IR) *ere 
prehcatcd 
TABLE 11 
REIGNITION DELAY 
700°C 8MJ'C 900°C 
1 6 i 6  2 2 2  
750" c 900' c 
(4) N~N(OH)~COI 296 i 50 29 t 5 6 -C 3 
INGREDIENTS TIME. SECONDS 
- 
(I) SnI2(68%) 380 '-c 80 2 i 2  
(2) K1(76% I )  >m 
(3)  Na l (854  1)  m - + m  3 . c  2 
1 
4,406,797 
3 
TABLE 11-continued 
REIGNITION DELAY 
INGREDIENTS TIME, SECONDS 
( 5 )  KAI(OH)ZCO~ 153 f 15 IO  f 4 
(6) KAl(OH)rCO, + Sn12(6% I) 51 h 3 
(7) KAI(OH)2CO) + Sn12(6% I) 50 f 2 
(8)  KAI(OH)2CO3 + KI(7S I)  13 -+ 4 
(9) KAI(OH),COi + KU7% I )  >900 50 f 14 
520 f 52 
419 * 51 
500 t 90 
NOTE: 
Mixtures (6) and (8) were mechanical mixtures. Mixlures (7) and (9) were preheated. 
TABLE 111 
REIGNITION 
DELAY TIME, sec. 
AT VARIOUS 
AIRFLOWS, mps 
DRY CHEMICALS GRAMS 6 36 
( I )  KCl (PYROCHEM) 30 <I 0 
20 
(2) KD 30 >20 05 
(3) KD + KCI (32%) 10-20 2 > 20 
(4) KI 40 < I  0 
(5)  KD + K1 (10%) 20 3 > 20 
(6) KD + K1 (5%) 20 I < I  
25 >20 - 
(7) KD + KI (9%) 15 <I < 20 
(8) KD + K1 (18%) 20 <I > 20 
(9) KD + Sn12(5%) 15 >20 > 20 
(10) KD + Snl2(10S0) I5  >20 > 20 
( 1 1 )  KD + Snl2(20%) IO >20 > 20 
- (SUPER-K) 50 
NO? E 
Minturer (6) to ( I  I )  were preheated 
Referring now to these tables and first to Table I, the 
more significant results are those set forth in the column 
headed 900" C., that being the temperature to which the 
test trough was heated. As will be seen, of the three 
aluminum compounds employed by themselves two 
resulted in no delay time in rekindling and one (alumi- 
num hydroxide) provided a delay time of only 3+2 
seconds. Results with stannous iodide and potassium 
iodide were similar. On the other hand, in each of the 
mixtures very significant improvement was noted. Thus 
in the case of aluminum hydroxide plus stannous iodide 
(7 percent iodine) the delay time was 8+ 1 seconds; in 
the case of the boehmite-potassium iodide mixture, the 
delay time was 15f4 seconds; and in the case of the 
alumina-potassium iodide mixture the delay time was 
50% 12 seconds. 
Referring now to Table I1 potassium dawsonite was 
the chosen aluminum compound. It is apparent that 
mixtures of potassium dawsonite with stannous iodide 
and with potassium iodide performed much better than 
either the dawsonite alone o r  the iodide alone. 
Referring now to Table 111, it is apparent, especially 
at higher rates of air flow and considering the quantities 
of extinguishant material which were used, that mix- 
tures of potassium dawsonite with a potassium halide o r  
stannous iodide performed much better than the indi- 
vidual components. 
4 
In preparing the mixtures of the invention a simple 
mechanical mixing is sufficient. It is preferred that each 
of the ingredients be in a finely divided state, for exam- 
ple about 250 to 350 mesh. Inasmuch as some of the 
5 iodides are somewhat hygroscopic, it is preferred that 
the iodide, or the mixture of iodide and aluminum com- 
pound, be heated to drive off moisture and that the 
mixture be kept in a reasonably airtight container. The  
principal disadvantage resulting from the presence of 
10 moisture is that the product does not pour as readily. It 
is important in extinguishing a fire on  a heated surface, 
such as a fire caused by leakage of jet fuel in a nacelle, 
that the extinguishant mixture be readily pourable so 
that it will spread rapidly and evenly over the burning 
It is therefore apparent that new and useful fire extin- 
We claim: 
1. A fire extinguishant composition comprising sub- 
20 stantial proportions each of (a) an aluminum compound 
selected from the group consisting of AI(OH3), AIOOH 
and alkali metal dawsonites and (b) a metal halide se- 
lected from the group consisting of alkali metal, tin and 
lead halides. 
2. The composition of claim 1 wherein components 
(a) and (b) are present in proportions of about 25 to 99 
percent of (a) and about 75 to 1 percent of (b). 
3. The composition of claim 2 wherein component (a) 
is an alkali metal dawsonite. 
4. The composition of claim 2 wherein component (b) 
is an alkali metal halide. 
5. The composition of claim 2 wherein component (a) 
is an alkali metal dawsonite and component (b) is an 
alkali metal halide. 
6. The composition of claim 1 wherein component (a) 
is potassium or sodium dawsonite, component (b) is 
potassium iodide, and the two are present in the porpor- 
tions of approximately 95 to 80 percent of the dawsonite 
and 50 to 20 percent of potassium iodide. 
7. A method of extinguishing fires arising from leak- 
age of fuel onto a hot solid surface, said method com- 
prising applying to the hot, flaming surface a powdery 
mixture of (a) an aluminum compound selected from the 
group consisting of aluminum hydroxide, boehmite, 
45 alumina and an alkali metal dawsonite, and (b) a metal 
halide. 
8. The  method of claim 7 wherein components (a) and 
(b) are present in the mixture in the proportions of about 
25 to 99 percent of (a) and about 75 to 1 percent of (b). 
9. The method of claim 7 wherein component (a) i s  an 
alkali metal dawsonite. 
10. The method of claim 7 wherein component (b) is 
an alkali metal iodide. 
11. The method of claim 7 wherein the mixture is a 
55 mixture of about 80 to 95 percent of an alkali metal 
dawsonite and about 20 to 5 percent of potassium io- 
dide. 
15 surface. 
guishant conipositions have been provided. 
25 
30 
35 
40 
so 
* * * * *  
65 


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