Classifications

• • A—HUMAN NECESSITIES
  • A62—LIFE-SAVING; FIRE-FIGHTING
  • A62D—CHEMICAL MEANS FOR EXTINGUISHING FIRES OR FOR COMBATING OR PROTECTING AGAINST HARMFUL CHEMICAL AGENTS; CHEMICAL MATERIALS FOR USE IN BREATHING APPARATUS
  • A62D1/00—Fire-extinguishing compositions; Use of chemical substances in extinguishing fires
  • A62D1/0028—Liquid extinguishing substances
• • A—HUMAN NECESSITIES
  • A62—LIFE-SAVING; FIRE-FIGHTING
  • A62D—CHEMICAL MEANS FOR EXTINGUISHING FIRES OR FOR COMBATING OR PROTECTING AGAINST HARMFUL CHEMICAL AGENTS; CHEMICAL MATERIALS FOR USE IN BREATHING APPARATUS
  • A62D1/00—Fire-extinguishing compositions; Use of chemical substances in extinguishing fires
• • A—HUMAN NECESSITIES
  • A62—LIFE-SAVING; FIRE-FIGHTING
  • A62D—CHEMICAL MEANS FOR EXTINGUISHING FIRES OR FOR COMBATING OR PROTECTING AGAINST HARMFUL CHEMICAL AGENTS; CHEMICAL MATERIALS FOR USE IN BREATHING APPARATUS
  • A62D1/00—Fire-extinguishing compositions; Use of chemical substances in extinguishing fires
  • A62D1/0007—Solid extinguishing substances
• • A—HUMAN NECESSITIES
  • A62—LIFE-SAVING; FIRE-FIGHTING
  • A62D—CHEMICAL MEANS FOR EXTINGUISHING FIRES OR FOR COMBATING OR PROTECTING AGAINST HARMFUL CHEMICAL AGENTS; CHEMICAL MATERIALS FOR USE IN BREATHING APPARATUS
  • A62D1/00—Fire-extinguishing compositions; Use of chemical substances in extinguishing fires
  • A62D1/0092—Gaseous extinguishing substances, e.g. liquefied gases, carbon dioxide snow

Definitions

• the present invention generally relates to prevention and extinguishment of fires of combustible materials by utilizing a composition of matter group which is highly efficient and environmentally friendly. More particularly, the invention relates to prevention and extinguishment of fires of combustible materials by using a group of fire suppressants having labile bonds between bromine atoms and atoms other than carbon.
• Halon 1 301 CF 3 Br
• Halon 1 21 1 CF 2 1 Br
• These compounds are very stable, so they survive long enough in the troposphere to be gradually transported to the stratosphere, where they are photolyzed by solar ultraviolet radiation to produce free radicals that catalyze ozone depletion as taught, for example, in J.G. Anderson, D.W. Toohey, and W.F. Brune, Science, 251 , 39 ( 1 991 ) . Production of these materials has therefore been internationally prohibited after January, 1 994 by the Montreal Protocol on Substances that Deplete the Ozone Layer. The problem is therefore to find fire suppression materials and methods which are at least as effective as Halon 1 301 and Halon
• compositions of matter having labile bromine atoms bound to atoms other than carbon have been discovered to have improved fire suppressant properties and to be environmentally friendly.
• Compounds which release bromine atoms and are commonly used as brominating agents in organic synthesis such as phosphorous tribromide (PBr 3 ), thionyl bromide (SOBr 2 ), boron tribromide (BBr 3 ), and the like are very efficient at extinguishing fires. Moreover, they hydrolyze or oxidize rapidly in the troposphere and consequently they have no stratospheric ozone depletion potential.
• SiBr 4 silicon tetrabromide
• TiBr 4 titanium tetrabromide
• IBr iodine bromide
• POBr 3 phosphorous oxybromide
• BrF 3 bromine trifluoride
• bromine pentaflouride (BrF 5 ) N- bromosuccinimide (C 4 H 4 O 2 NBr) ⁇ the bromine is bound to nitrogen, not carbon ⁇ , nitrosyl bromide (NOBr) chlorine bromide (CIBr), and cuprous bromide (CuBr).
• non-labile bromine compositions are found in such high-melting, ionically bound salts as lithium bromide (LiBr, m.p. 547° C), calcium bromide (CaBr 2 , m.p. 730° C), or chromous bromide (CrBr 2 , m.p. 842° C), and other bromine-containing compositions that are thermally and oxidatively stable according to criteria familiar to people practiced in the art of synthetic chemistry.
• equipment for delivering the composition incorporates such factors as specific geometry, gas flow, and flame conditions.
• a method of delivery of a composition having one or more liquid compounds of the aforesaid class of fires suppressants may employ a nonflammable, pressurized gas to propel the composition through a nozzle to the flame.
• Another method of delivery of liquid compositions may employ a deflagrating solid, gas-generating cartridge, such as is found in automotive airbags, to propel a mist of liquid to the flame.
• a third method for delivery of liquid compositions may employ a pressurized liquid propellant such a liquid carbon dioxide or liquid argon to atomize and direct a mist of suppressant onto the flame.
• Other methods for propelling powders or slurries of solid materials of the aforesaid class may employ a deflagrating solid gas generating cartridge and a wider nozzle such as would be used for na ordinary shotgun cartridge.
• Other methods for propelling gaseous materials of the aforesaid class may employ mixtures with pressurized inert propellants to aid transport of suppressant to the flame.
• the effectiveness of the class of suppressants described herein is a result of the relative ease with which bromine atoms are liberated in a flame environment.
• Halons 1 301 and 1 21 1 also liberate bromine atoms in a flame; however, the strength of the C-Br bond in these materials requires higher temperatures or longer interaction times than the compositions of matter described herein.
• the stability of the Halons against oxidation or hydrolysis in the troposphere is one indication of the stability of the C-BR bond.
• the compositions of matter described herein are not stable in the presence of water, oxygen, or heat, liberating bromine atoms under these conditions and thereby providing a catalyst for flame suppression.
• Another indication of the stability of the C-Br bond is the measurement of its bond dissociation energy of 68 kilocalories per mole as taught by A.H. Sehon and M. Szwarc (Proceedings of the Royal Society (London), page 1 10, [1 951 ]). This energy is larger than the bond energy of typical P-Br bonds (63 kcal/mole), l-Br bonds (43 kcal/mole), or S-Br bonds (52 kcal/mole) as taught by Streitweiser and
• TiBR 4 solid 87 reacts with water
• IBr solid 39 decomposes at 1 1 6 ° C
• liquid SOBr 2 is introduced as an air- pressurized mist into a 500,000 Btu/hr fire resulting from kerosene flowing at a rate of 4 grams per second through a nozzle with cross-flowing compressed air to atomize the liquid into a fine mist.
• the fire is contained in a flame holder whose volume is approximately 8 liters and is further blown by an atmospheric cross-wind of 40 miles per hour.
• the fire is reproducible and irreversibly extinguished with less than one gram of SOBr 2 in less than 0.2 seconds as confirmed by videotape records of the experiments.
• the same fire is not reproducible suppressed with aliquots of 25 grams of CF 3 Br added to the same location.
• PBr 3 0.2 cubic centimeters of PBr 3 is mixed with 0.7 cubic centimeters of liquid carbon dioxide.
• the liquid CO 2 propels the PBr 3 through a valve and into the flame zone, generated as herein above described, as it is opened, irreversibly and completely extinguishing the flame in the presence of flowing fuel, air, and hot surfaces.
• Halon 1 301 Extinguishment of a similar fire, with a hydrocarbon fuel burn rate of 1 2 grams per second, by Halon 1 301 is taught by Alvarez in chapter 3 of Gann (ibid.) to require between 90 and 1 30 grams per second of CF 3 Br for suppression.
• Halon 1 301 for reproducible suppression.
• the quantity of Halon 1 301 required to suppress a similar fire is between 1 00 and 1 000 times greater than that required of the compositions of matter described herein above, of which SOBr 2 and PBr 3 are specific embodiments.
• the labile bromine atoms and high proportion of bromine in the composition of matter listed in Table I provide a more efficient fire suppression formulation than the Halons, which typically have less bromine by weight (Halon 1301 and 121 1 are 54% and 48% Br, respectively) and lesser proclivity for liberating bromine atoms when thermally or chemically activated in a combustion environment.
• Methods for dispersing gas, liquid, or solid suppressants require designs based upon such factors as specific geometry of the locus of the fire, flow properties of the fire suppressants, and flame conditions of the fire. For example, fine mists of liquid are transported by fluid-dynamical drag forces along flow streamlines in the nacelle of an aircraft engine. The mists vaporize in hot zones, liberating bromine atoms by pyrolysis in precisely the regions where the heat released by combustion is most intense. Inasmuch as the drag coefficient is inversely proportional to the droplet diameter, as is known to people practiced in the art of fluid dynamics, there is a range of aerosol size distributions which most effectively deliver specific suppressants to specific fires.
• Dispersing methods designed for suppressing fire in the nacelle of a jet engine differ from dispersing methods designed for suppressing fire in the engine compartment of a motor vehicle, the flu of a chimney, or the gas- handling manifold of a semiconductor processing clean-room.

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• Chemical & Material Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• General Chemical & Material Sciences (AREA)
• Business, Economics & Management (AREA)
• Emergency Management (AREA)
• Fire-Extinguishing Compositions (AREA)
• Fireproofing Substances (AREA)
• Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)

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• 1996
  • 1996-10-08 DE DE69608707T patent/DE69608707T2/de not_active Expired - Lifetime
  • 1996-10-08 EP EP96936260A patent/EP0932432B1/de not_active Expired - Lifetime
  • 1996-10-08 WO PCT/US1996/016089 patent/WO1998015322A1/en active IP Right Grant
  • 1996-10-08 JP JP51746898A patent/JP3868500B2/ja not_active Expired - Lifetime
  • 1996-10-08 AU AU73952/96A patent/AU7395296A/en not_active Abandoned

Non-Patent Citations (1)

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