Note: Descriptions are shown in the official language in which they were submitted.
-
2 1 80586
~ Ar.r.Y Rr!NTrN NON-T~'YTC
FIRE F~QODING ~ rs
FI~ F T~ INVRNTION
This invention involves novel total flooding and
streaming-type fire exting~; RhAnt~ and novel detoxifiers
which are envirnnmPnt;~l 1 y safe and non-toxic in natural
form as well as fire exposed degraded forms.
DESrr~TPTION OF ~ P~TOR ART
In recent years, it has been discovered that
certain halocarbons such as CFC 11, CFC 12, Halon 1301, and
15 the like, which have been widely used as refrigerants,
blowing agents and fire exting~ hAnte are damaging to the
environment because they accumulate in the stratosphere and
damage the integrity of the ozone layer, which protects
life on earth from harmful radiation from the sun and
20 3pace. These harmful substance3 are being phased out of
product ion .
Halocarbons have been used as f ire
extinglli~h~ntR. Thacker, U.K. 1,603,867, discloses CFC 11
25 and CFC 12 in combination with a monoterpene, that is, an
essential oil or citrous oil, as a fire extinguishing
agent. A monoterpene is defined in the chemical literature
as CloHI6. As stated, CFC ll and CFC 12 are now well known
to be detrimental to the ozone layer.
Halocarbon exting ~ hi~ntf~ fall into two broad
groups, streaming agents and flooding agents. A streamlng
agent is directed at the source of the fire and should be
high boiling to thereby resist decomposition until it
35 reaches the source of the fire. A flooding agent fills a
volume around the fire and smothers the fire. It should be
low-boiling 80 that it vaporizes readily.
~ 2 ~ 80586
-- 2
U.S Patent No. 4,826,610, issued May 2, 1989,
Derek A. Thacker, discloses a firefighting composition
comprising one or more halocarbons, namely Halons 11 (CFC
11), 12 (CFC 12), 113 (CFC 113) and 114 (CFC 114), together
5 with 1~ to 14~ by weight of the extinguishant base of a
sesquiterpene and one or more essential oils. A
sesquiterpene is a compound having the formula Cl5U24.
Solvents and dispersing agents may also be provided. This
composition is suited for stream-type firefighting si tu-
10 ations. The formulation is not touted to be ozone friend-
ly .
United States Patent No. 4,954,271, issued
September 4, 1990, Raymond W. Green, discloses and protects
15 high boiling enviL~ ~l ly amicable gtream-type fire
extinguishing agents. The stream-type agents comprise in
combination: (a) more than 50~ by weight of a fluoro-
chlorocarbon selected from the group consisting of: 1,1-
dichloro-2, 2, 2-trifluoroethane, and 1,2-dichloro-2, 2-
20 difluoroethane; (b) less than 48~6 by weight of a fluorocar-
bon selected from the group consisting of: chlorodifluoro-
methane, 1-chloro-1, 2, 2, 2-tetrafluoroethane, penta-
fluoroethane, 1, 2, 2, 2-tetrafluoroethane; and (c) a
detoxifying substance selected from the group consisting of
25 terpenes: citral, citronellal, citronellol, l; ~nf~,
dipentene, menthol, terpinene, terpinolene, sylve~trene,
sabinene, methadiene, zingiberene, ocimene, myrcene, ~-
pinene, ~-pinene, turpentine, camphor, phytol, vitamin A,
abietic acid, squalene, lanosterol, saponin, oleanolic
30 acid, lycopene, ~-carotene, lutein, o~-terpineol, and p-
cymeme; and unsaturated oils; oleic acid, linoleic acid,
linolenic acid, eleosearic acid, lincanic acid, ricinoleic
acid, palmitoleic acid, petroselenic acid, vaccenic acid,
and erucic acid, in the range of from 2 to 10~6 by weight.
In the chlorof luorocarbon stream- type mixtures
taught by Green, it is emphasized that high boiling chloro-
~ 2 1 805~6
-- 3
fluorocarbons should comprise more than 50~ weight of his
mixtures. In contrast, low boiling compounds must be less
than 50~ weight ~see column 2, lines 22-27). In the
examples disclosed in Green, a low boiling chlorofluoro-
carbon such as CFC 12, which boils at -30~C, amounts to 15%
weight of the total form-llAt;nn. The other components are
in the vast majority and boil at temperatures well above
0~C. For ;ncltAn~, in Example 2 of Green, column 4, line
61, the boiling point of the NAF Interior Mixture is stated
as being 10~C. Thus, the high boiling mixtures disclosed
by Green are useful as stream-type exting~ hAnt~ and are
virtually the opposite of the low boiling mixtures which
are suitable as flooding agents.
Two U. S . patents, U. S . Patent No . 5, 141, 654,
issued August 25, 1992, F~rnAn~f~7~ and IJ.S. Patent No.
5,393,438, issued February 28, 1995, FPrnAn~7, are of
general interest because they digcloge exting-~ hAnt~
Both patents of Ff~rnAnr~ disclose chlorofluorocarbons
which are not ~ully halogenated, with the provision that
there be at least one fluorine atom (see column 2, line 57,
of 5,141,654~ in each halocarbon. However, the halocarbons
are used in pure form. There is no disclosure in either
F-~rnAn~1~7 patent of using one or more detoxifying sub-
stances. Furthermore, neither FPrnAn-1.o7 patent discloses
any significance inherent with low boiling chlorofluoro-
carbons .
SUMM~RY OF THE INVE~IQN
The invention pertains to a f ire extinguishing
mixture of the formula:
(a) about 909c to 100 . 0~6 wt . of a halocarbon
selected from the group consisting of:
hydrochlorofluorocarbon.21 - dichlorofluoromethane
hydrochlorof luorocarbon . 2 2 - ch~orodi f luoromethane
hydrofluorocarbon 23 - trifluoromethane
-
~ 2~8~586
hydrochlorofluorocarbon.123 - 2,2-dichloro-1,1,1-
trif luoroethane
hydrochlorof luorocarbon . 123a - 1, 2 -dichloro-1, 1, 2 -
trif luoroethane
hydrochlorofluorocarbon.124 - 2-chloro-1,1,1,2-
tetraf luoroethane
hydrochlorofluorocarbon.124a - 1-chloro-1,1, 2, 2-
tetraf luoroethane
hydrofluorocarbon 125 - pentafluoroethane
hydrochlorofluorocarbon.131 - chlorotrlflll--roethalle
hydrochlorofluorocarbon.132 - 1,2-dichloro-1,1-
dif luoroethane
hydrochlorofluorocarbon. 133 - 2-chloro-1, 1,1-
trifluorethane
hydrofluorocarbon.134a - 1,1,1, 2-
tetraf luoroethane
hydrofluorocarbon.227 - heptafluoropropane
hydro f luorocarbon . 2 3 6 - hexa f luoropropane
hydrofluorocarbon.245 - pentafluoLu~,~J~dlle; and
(b) between 0.25 and 10~ by weight of a
detoxifying substance selected ~rom the group consisting
of:
ethene propene butene
isopropene pentene isopentene
25 trimethylethene tetramethylethene butadiene
z-methylbutadiene pentadiene isobutylene; and
1, 3-butadiene;
the mixture having a boiling point of between
about -85~ or -80~C and about -10~C to 25~C, a formula
molecular weight in the range of about 70 to 250, and a
vapour pressure of about 0.1 MPa to about 5 MPa at 25~C,
said fire extinguishing agent being non-toxic and environ-
mentally benign in both natural form and degraded fire
exposed form.
In another aspect, the invention pertains to an
additive for halogenated fire exting-i~h~ and fire
2 1 805~6
-- 5
extingui~hing flooding mixtures consiRting of one or more
hydrocarbons having f rom two to six carbon atom~, with one
or more double bonds, said additive reducing the amount of
hydrogen halides and carbonyl halides that are produced on
5 exposure of the extinguishant or mixture~ to fire. The
additive for halogenated fire exting~l; Rh~ntR and fire
extinguishing mixtures can have four or more carbon atoms
with two or more double bonds, where at least two of the
double bonds are conjugated.
The additive can be selected from the group
consisting of: ~
ethene propene butene
isopropene pentene . isopentene
15 trimethylethene tetramethylethene butadiene
2-methylbutadiene pentadiene isobutylene; and
1, 3-butadiene;
The invention iR also directed to a specif ic
20 additive for halogenated fire extinguishants and fire
extinguiRhing flooding mixtures consisting of l,3-
butadiene, said additive reducing the amount of hydrogen
halides and carbonyl halides that are produced by the
halogenated f ire extinguishants and f ire extinguishing
25 mixtures on exposure to fire. The fluid viscosity of the
mixture can be below l. 0 ccntipoise between the initial
boiling point of the mixture and 25~C.
The invention is also directed to a non-toxic
30 envill -It~l ly benign fire extinguishing mixture for use
in a flooding fire extinguishing techni~ue, said fire
extinguishing mixture comprising about 8296 by weight HCFC-
22, about 9.5~ by weight ~CFC-124, about 4.75g6 by weight
HCFC-123 and about 2~ by weight 1,3-butadiene.
~ 21 u0586
-- 6
DETATT Rn DES~RTPTION OF ~ kt~:~]
EMBODI~Rl~TS OF TT~ INVENTION
The inventors have determined that f ully
5 halogenated halocarbons are highly stable, have long
lifetimes, and are difficult to decompose. Thus when fully
halogenated halocarbons enter the stratosphere, they take
a long time to decompose and hence the damage time on the
ozone layer is extensive.
Specifically, two chlorofluorocarbons disclosed
in Thacker, U.S. Patent No. 4,826,610, are fully
halogenated compounds. In other wordA, all of the avail-
able substitution pos~tion6 on the carbon backbone are
taken up by either chlorine or fluorine. Thacker did not
recognize that fully halogenated chlorofluorocarbon com-
pounds are highly stable, difficult to decompose, and hence
are a primary enemy of the ozone layer enveloping the
earth .
Specifically, Green discloses high boiling fully
and partially halogenated chlorofluorocarbon mixtures which
are suitable as streaming extingll~Ahi~rtA. The Green
mixtures comprise the following chlorofluorocarbons: CFC
11, CFC 12, CFC 22, CFC 114, HCFC 123, HCFC 124, HFC 125,
HCFC 132 and HFC 134. Of these chlorofluorocarbons, CFC
11, CFC 12 and CFC 114 are fully halogenated chloro-
f luorocarbons . Green did not acknowledge the dif f erence
between fully and partially halogenated chlorofluorocarbons
and that chlorofluorocarbons that are fully saturated with
halogen atoms are difficult to decompose and are harmful to
the ozone layer protecting the earth.
The inventors have invented a family of low
boiling partially halogenated chlorofluorocarbon ~ormula-
tions, which are ideal as fire flooding agents. Further-
more, the formulations are environmentally benign because
21 8~5~6
the haloearbons are not fully halogenated, that is, tllere
is always at least one hydrogen atom present in the
ehlorofluoroearbons and fluoroearbons eomprising the
family. In other words, the low boiling partially
5 halogenated ehlorofluoroearbon eompounds disclosed herein
provide at least one hydrogen site on each molecule whieh
thereby provides a location for the breakdown or deeomposi-
tion of the molecule.
As is well understood in the art, the inclusion
of hydrogen in a compound changes the physical and ehemieal
eharaeteristies of that eompound suf f ieiently that it is
not immediately predietable or obvious that the eompound
ineluding the hydrogen atom will function or perform in a
15 manner that is similar to eompounds whieh are fully
halogenated. The inelusion of hydrogen, a highly flammable
and reactive element in its lln~ - in~-l form, in a fully
halogenated hydroearbon to thereby render it only partially
halogenated, can be expected by a person skilled in the art
20 to dramatically alter the chemical characteristics of the
fully halogenated hydrocarbon. It is unlikely that a
person skilled in the art would expect that a partially
halogenated aliphatic hydrocarbon could be substituted for
a fully halogenated aliphatic hydrocarbon in a flood-type
25 fire extinguishing mixture because the results would not be
predictable .
Furthermore, knowledge ac~[uired by a skilled
artisan from stream-type halocarbon exting~ h~nt~ cannot
30 be extrapolated with predictability to flood-type
halocarbon exting-1; 4h~nt~,
At the time of development of the Thacker and
Green stream-type fire extinguishing fur ll~t;~n~, indis-
35 criminately using by and large high boiling fullyhalogenated chlorof luorocarbons, Thacker and Green did not
disclose that such chlorofluorocarbons would be damaging to
~ 2 1 80586
the ozone layer encompassing the earth. Furthermore,
Thacker and Green would not have been aware of global
warming consequences of their fully halogenated chloro-
f luorocarbons .
The low boiling fire flooding mixtures disclosed
by the inventors herein are partially halogenated halo-
carbons and have highly desirable low ozone depletion
potentials, and perform well as fire flooding agents, in
10 natural form as well a3 degraded form which occurs on
exposure of the extinguishant to fire.
We have also invented a family of low boiling
hydrocarbons of two to 3iX carbons with one or more double
15 bonds in each molecule, for use in detoxifiers (or acid
scavengers) in association with low-boiling halocarbo~s
used as flooding-type exting~l; Rh~nt~.
Overall, we have invented a family of lower
20 alkenes detoxifying agents which, when used in combination
with a f amily of new hydrochlorof luorocarbon and hydro-
fluorocarbon fire extinguishing agents, make ideal flood-
type fire e~ctingl];~h~t~ and also rehder the decomposed
halocarbons non-toxic and cause minimum damage to the ozone
25 layer of the earth. The family of flood-type
exting~ h~nt~: I have invented contain no bromofluoro-
carbons which have been discovered to have serious ozone
damagi~g ef f ects .
Fire extinguishing mixtures for flooding applica-
tions, that is, smothering the fire by filling a volume
space, as opposed to streaming the fire extinguishing agent
onto the source of the fire, should be considerably more
volatile than for streaming-type applications. In stream-
ing applications, the mixture should remain cohesive and
resist decomposition due to heat, until it reaches the
source of the fire. The need for cohesion of the mixture
21 8G~86
in flooding-type situations is not only reduced but in fact
cohesion becomes detrimental to rapid dispersion of the
agent throughout the volume. Thus, for flooding applica-
tions, it is desirable that the halocarbons making up the
5 extinguishant have low boiling points. It is also desir-
able that the detoxifying substance used in the ~ormula-
tions for flooding applications have a lower boiling point
than that used for streaming-type applications. Lower
boiling points of both the halocarbons and the detoxifiers
10 promote disper3ion.
Apart from that, we have discovered that some of
the substances listed by Thacker and Green can in some
cases leave an undesirable terpene or ses~uiterpene residue
15 when used in flooding applications to extinguish fires
(even though the Green and Thacker formulations are primar-
ily intended for stream-type use).
While we do not wish to be bound by any theories,
20 we believe that the halogen scavenging by the detoxifier
when a halocarbon is used as a fire extinguishant takes
place on a molecular basis and thus lower molecular weight
detoxifiers are re~uired at a lower weight fractions of
halocarbons to achieve the same degree of detoxification as
25 in the case oi higher molecular weight compounds.
We have discovered that low-boiling light hydro-
carbons with two or more con~ugated double bonds are
particularly e~ective as detoxifiers (acid scavengers) for
30 low-boiling halocarbons used as flooding exting~ hi~n~R.
There is resonance stabilization of formed intGrr~~; ~te
products during the halogen scavenging process when the
low-boiling halo~-~rh~-n~ are used a3 a flooding fire extin-
guishants. Alkenes, having six or less carbons and one or
35 more double bonds, have higher vapour pre~sures and lower
boiling points than the terpene additives listed by Green.
2180586
-- 10 --
Again, regarding halocarbons and ozone layer
damage, we do not wish to be bound by any adverse theories.
However, we offer the following discussion as a possible
aid to understanding why the low boiling halocarbons we
5 have invented are successful as enviI~ -nti~l ~y friendly
flood-type extinguishants. Halocarbons which contain at
least one hydrogen, we believe, are generally more environ-
mentally benign than their fully halogenated counterparts
because the presence of even a single hydrogen on a halo-
10 carbon molecule provides a site which is subject to attackby hydroxyl radicals. This leads to breaking down of the
molecule and a drastic reduction in the atmospheric life-
time of the molecule. The ozone depletion potential of a
compound is, we believe, dependent on its atmospheric
15 lifetime mainly due to the long time that it takes the
compound to be transported from near the earth~s surface up
and into the stratosphere. Global warming pot-~nt;;-l~ are
also strongly dependent on atmospheric lifetime as the time
integrated climate forcing of even a strongly absorbing
20 molecule will be minimal if the molecule does not survive
a significant time in the atmosphere. Our invention
therefore involves using partially halogenated halocarbons
which contain at least one ~lydr U~t:ll to thereby provide a
molecule breakdown site and thus the compound is relatively
2 5 envi r ~ t i~ 1 1 y benign .
When a f looding or inerting f ire extinguishing
technique is to be used, that is, where the extinguishant
is released into an enclosed volume cr-nt;~;n;n~ a fire, and
30 maximum toxic decomposition products are generated, we have
discovered that fires of this type are ~uickly and safely
extinguished using low-boiling partially halogenated non-
toxic mixtures as follows:
(a) 90 to 99 . 996 by weight of one or more of:
dichlorofluoromethane (HCFC 21)
chlorodifluoromethane (HCFC 22)
- 11 - 2~8~586
trifluoromethane (HFC 23)
dichlorotrifluoroethane (HCFC 123)
chlorotetrafluoroethane (HCFC 124)
pentafluoroethane (HCFC 125)
dichlorodifluoroethane (HCFC 132)
chlorotrifluoroethane (HCFC 133)
tetraf luoroethane (HCFC 13 4 )
heptafluoLu~lu~alle (HFC 227)
pentafluu~u~Lu~alle (HFC 245)
hexafluo,u~lu~alle (HCFC 236)
(b) 0.1~ to 1096 weight of one or more hydrocar-
bons having from two to six carbon atoms, and one or more
double bonds .
The mixture should be relatively volatile and
preferably have a boiling point between -85~C and 25~C, a
formula molecular weight between 70 and 250 and a vapour
pressure between about 0.1 MPa and 5 MPa at 25~C.
The 0.196 to 10~ by weight of any one or more
detoxifying hydrocarbons with from two to 8iX carbon atoms,
with one or more double bonds, may be one or more of the
following light alkenes:
ethene propene butene
isopropene pentene isopentene
trimethylethene tetramethylethene butadiene
2-methylbutadiene p.on~ l; .on~ isobutylene
3 o1, 3 -butadiene
The precise choice of agents and compositions
will be governed in each case by a balance of cost, factors
governing fluid and vapor flow, factors governing fluid and
35 vapor physical characteristics, and the configuration of
the extinguishant flooding system nee~ed to protect the in-
tended volume (8) .
- 12 - 2 1 805~6
We have also discovered that for extinguishing
f ires in enclosed volumes by f looding or inerting tech-
niques, it is critical that the initial boiling point o~
the f ire extinguishant is low. This includes both the
5 halocarbons and the detoxifier. We have also discovered
that it i3 important in such flooding fire exting l; ~hAnt~
that the detoxifying agent (8) has a low boiling point which
coincides closely with that o~ the halocarbon ( s ) so that
they volatilize at the same time.
The mixtures we have invented that are suitable
for flooding or inerting fire extinguishing agents have the
following beneficial characteristics and attributes:
1. The class of fire flooding mixtures according to
the invention must be rich in lower boiling
compounds, and not exhibit much cohesion. The
flooding class we have described will therefore
rapidly vaporize and flood the intended volume
with extinguishant to a concentration level that
is required to smother or inert the gaseous phase
and prevent or extinguish the included f ire .
2. The low boiling points exhibited by our class of
flooding mixtures enables low boiling detoxifying
agents to be used. This comprises low boiling
light unsaturated alkenes which cannot, because
of their low boiling points, be successfully used
with higher boiling streaming-type
3 0 ext ing~ h il n t .~,
5. We have found surprislngly that when the
detoxifying agents are eliminated completely from
the fire extinguishing mixtures, the fire extin-
guishing capacity is less efficient than when the
detoxifying compounds are included in the agents.
Also, when detoxifying lower alkenes are omitted,
- 13 - 2 1 8()5~36
dangerous levels of toxic halogen and hydrogen
halides are produced when the halocarbon extin-
guishant mixture i3 decomposed by the heat of the
fire.
6. To maximize the foregoing attributes, we have
determined that the physical characteristics of
a f looding mixture should have a boiling range
between -80~C and -10~~. It should also have a
lo liquid viscosity less than 1. 0 centipoise
throughout a temperature range from initial
boiling point of the mixture to approximately
25~C.
Exam~le
In one particular test, a test chamber measuring
0.5 x 3 x 3 meters and ~r~ntA;n;ng five standard pot fires
was f looded using a pipe system about 3 meters in total
20 length. The pot fires were extinguished in less than 10
seconds by using 1 kg of a mixture consisting of 96 percent
by weight of chlorodifluor~mf~thAn~ and 4 percent by weight
Of 1; ~ n~nf~ through the pipe . This mixture had an initial
boiling point of -40.5~C and a liquid viscosity of 0.21
25 centipoise at 25~C.
Exam~le 2
In another evaluation using the same test chamber
30 as in Example 1, the five pot fires were extinguished in
less than 10 seconds using 1 kg of a mixture consisting of
85 percent by weight of chlorodifluoromethane, 11.5 percent
by weight of 1- chloro -1, 2, 2, 2 - tetraf luoroethane, and 3 . 5
percent by weight of dipentene
2 ~ 8~586
-- 14 --
Examb~le 3
In a third test using the same test chamber as ln
Example 1, the five pot flres were extinguished in less
S than 10 seconds using 1 kg of a mixture consisting of 65
percent by weight of chlorodifluoromethane, 15.5 percent by
weight of 1,2-dichlorotetrafluoroethane, 15.5 percent by
weight of trichlorof luoromethane, and 4 percent by weight
Of l; ~nP. This mixture had an initial boiling point of
-27~C and a fluid vlscosity of 0.28 centipoise at 25~C.
Exam,,le 4
In a fourth application using the same test
chamber as in Example 1, the f ive pot f ires were extin-
guished in less than 10 seconds using 1 kg of a mlxture
consisting of 65 percent by weight of
dichlorodifluoromethane, 15.5 percent by weight of 1,2-
dichlorotetrafluoroethane, 15.5 percent by weight of
trichlorofluoromethane and 4 percent by weight o~ rAnp,
This mixture exhibited an initial boiling point of -13~C
and a viscosity of 0.36 centipoise at 25~C.
F;XA le 5
In a fifth test using the same test chamber as in
Example l, the f ive pot f ires were extinguished in less
than 10 seconds using 1 kg of a mixture consisting of about
65 percent by weight of dichlorodifluoromethane, about 15.5
percent of 1,2-dichlorotetrafluoroethane, about 15.5
percent by weight of trichlorof luoromethane, and about 4
percent by weight of dipentene.
ExamAle 6
In a sixth evaluation using the same test chamber
as in Example 1, the five pot fires were extinguished in
~ ~ ~ 805~6
-- 15 --
less than 10 seconds using 1 kg of a mixture consisting of
about 75 percent by weight of chlorodifluoromethane, about
11.75 percent by weight of 1,1-dichloro-2,2,2-trifluoro-
ethane, about 9.5 percent by weight of 1-chloro-1,2,2,2-
5 tetrafluoroethane, and aboout 3.75 percent by weight ofl; nF~.
Exam~le 7
In fire extinguishing tests conducted using a
mixture of HCFC's in the ratio 82:9.5:4.75 HCFC-22:HCFC-
124:HCFC-123, it was found that when 2 parts of 1,3-
butadiene were added, the HF concentrations generated
decreased by 60~ compared to the tests where no hydrocarbon
15 was added to the HCFC mixture.
These examples vividly demonstrate the key role
that low fluid viscosity and low boiling point plays in
parameterizing the mixtures required to achieve optimum
20 volume of flood-type fire extin~uishin~ performance. The
goal is to achieve mixtures having an initial boiling point
appr~ ;r~;n3 -60~C and a fluid viscosity approximating
o.15 centipoise at 25~C.
As will boe apparent to those skilled in the art
in the light of the foregoing disclosure, many alterations
and modifications are possible in the practice of this
invention without departing from the spirit or scope
thereof. Accordingly, the scope of the invention is to be
3 0 conE~trued in accordance with the substance def ined by the
following claimg.
