EP0447538A1 - Compositions extinctrices de feu, procedes et systemes utilisant du bromodifluoromethane - Google Patents

Compositions extinctrices de feu, procedes et systemes utilisant du bromodifluoromethane

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Publication number
EP0447538A1
EP0447538A1 EP90915893A EP90915893A EP0447538A1 EP 0447538 A1 EP0447538 A1 EP 0447538A1 EP 90915893 A EP90915893 A EP 90915893A EP 90915893 A EP90915893 A EP 90915893A EP 0447538 A1 EP0447538 A1 EP 0447538A1
Authority
EP
European Patent Office
Prior art keywords
fire
bromodifluoromethane
composition
fire extinguishant
tetrafluoroethane
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP90915893A
Other languages
German (de)
English (en)
Inventor
Yuichi Iikubo
Mark Lester Robin
Thomas P. Fidelle
Richard S. Rose
Mark A. Sweval
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Great Lakes Chemical Corp
Original Assignee
Great Lakes Chemical Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from US07/439,738 external-priority patent/US5124053A/en
Priority claimed from US07/488,295 external-priority patent/US5113947A/en
Application filed by Great Lakes Chemical Corp filed Critical Great Lakes Chemical Corp
Publication of EP0447538A1 publication Critical patent/EP0447538A1/fr
Withdrawn legal-status Critical Current

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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
    • A62D1/0057—Polyhaloalkanes

Definitions

  • the present invention relates to the field of fire extinguishant compositions, and particularly to extinguishant mixtures including bromodifluoromethane. These compositions display a surprising efficacy in fighting fires, and also are characterized by low ozone depletion potential (ODP), low toxicity and minimal decomposition during extinguishment.
  • ODP ozone depletion potential
  • compositions should be relatively inexpensive, readily discharged onto the fire, and low in both toxicity and ozone depletion potential.
  • Various materials have been considered in the past for use as fire extinguishants, and some are in widespread commercial use. However, these chemicals generally have drawbacks in respect to one or more of these desired properties.
  • bromodifluoromethane is a very effective extinguishing agent, and in fact on a weight basis is superior to Halon 1211
  • bromodifluoromethane is also known to undergo hydrolysis to form HBr and difluorocarbene, CF2, as described in Hine and Langford, J. Amer. Chem. Soc., 79, 5497 (1957), and it might be expected that such behavior would also render bromodifluoromethane toxic.
  • LC50 values the concentration of agent required to cause death in half of the sample population
  • bromodifluoromethane is of approximately the same toxicity as Halon 1211, and the concentrations required for extinguishment with bromodifluoromethane are at levels safe to living
  • bromochlorodifluoromethane These compounds are asserted by some to be capable of destroying the earth's ozone layer, which forms a protective shield against harmful ultraviolet radiation. Clearly a need exists for an effective agent that presents a reduced threat to the earth's protective ozone layer.
  • extinguishing compositions are also discussed in United States Patent No. 3,479,286, issued to Gambaretto. This patent describes a two component system combining a completely halogenated alkane and a chlorofluorohydrocarbon. Japanese Patent No. 58078677 describes fire extinguishing compositions which comprise three component systems including
  • bromotrifluoromethane dibromotrifluoroethane and a cyanamide derivative.
  • bromomethanes typically perhalogenated compounds
  • bromodifluoromethane is not included in any of these references. Instead, bromodifluoromethane is identified in Japanese Patent No. 59221375 as useful in an aerosol composition, and in United States Patent Nos. 2,639,301 and 4,810,403 as a refrigerant for air conditioning units.
  • bromodifluoromethane are effective fire extinguishing agents which satisfy the foregoing criteria.
  • an effective and low ozone depleting method for extinguishing a fire which includes introducing to the fire a fire extinguishing concentration of
  • bromodifluoromethane or mixtures of bromodifluoromethane and a compatible propellant include nitrogen, carbon dioxide, trifluoromethane, carbon
  • the invention also includes fire extinguishant compositions comprising
  • bromodifluoromethane and a compatible propellant which are characterized by desirable fire fighting efficacy and other advantageous physical properties, such as low ozone depletion potential.
  • an effective and low ozone depleting method for extinguishing a fire which includes introducing to the fire a fire extinguishing concentration of a composition including a mixture of bromodifluoromethane and at least one other
  • fluorocarbon fire extinguishant includes bromotrifluoromethane,
  • the invention also provides fire extinguishant compositions, characterized by high fire extinguishing efficacy and low ozone depletion potential, and comprising mixtures of
  • bromodifluoromethane and at least one other fluorocarbon fire extinguishant may further include a compatible propellant.
  • compositions of the present invention have a phase equilibrium pressure of between about 45 psig and about 600 psig at 70°F.
  • the compositions in certain embodiments comprise ozone depletion potentials of less than about 3.0, and even below about 1.0.
  • compositions consist essentially of bromodifluoromethane and propellant, or of
  • bromodifluoromethane propellant and at least one other fluorocarbon fire extinguishant.
  • extinguishants have low ozone depletion potential and good fire extinguishing efficacy.
  • the present invention is also directed to fire
  • compositions comprising discharging from a pressurized container into the combustion zone of a fire, a fire extinguishing amount of a fire extinguishant composition comprising any of the
  • compositions defined hereinabove are compositions defined hereinabove.
  • Another object of the present invention is to provide fire extinguishant compositions which include bromodifluoromethane, alone or in mixture with one or more other fluorocarbon components, the bromodifluoromethane itself and the resulting mixtures being surprisingly effective as fire extinguishants and having relatively low ozone depletion potential and toxicity.
  • FIG. 1 is a perspective view of a room enclosure having a total flooding system in accordance with one aspect of the present invention.
  • FIG. 2 is a schematic, cross-sectional view of a portable fire extinguisher useful in accordance with the present invention.
  • FIG. 3 schematically illustrates a connection between the container of a fire extinguisher and a valve for discharge of extinguishant composition from the extinguisher
  • connection including an O-ring seal of EPDM rubber.
  • the present invention provides surprisingly effective methods and compositions for fire extinguishing.
  • the fire extinguishant compositions comprise bromodifluoromethane as well as mixtures of bromodifluoromethane and other
  • bromodifluoromethane is an effective fire extinguishant, and moreover that it has a desirably low ozone depletion potential (ODP).
  • ODP ozone depletion potential
  • blends of bromodifluoromethane with other extinguishants also exhibit superior fire extinguishing qualities and low ozone depletion potentials. It has further been discovered that certain of the extinguishant mixtures of the present invention generally have even greater efficacy than would be predicted based upon the combination of the separate compounds. This synergistic result makes the
  • inventive mixtures unexpectedly useful as fire extinguishants.
  • bromodifluoromethane have also been demonstrated to have low toxicity and minimum temperature dependency, and to be capable of effective use in a wide variety of fire extinguishing applications. Importantly, it has been demonstrated that such compositions containing bromodifluoromethane can replace high ozone depletion potential fire extinguishing agents in existing equipment.
  • Bromodifluoromethane has the molecular formula CHF 2 Br and is understood to have the following structural formula:
  • Bromodifluoromethane may be prepared by a number of methods, including fluorination of bromoform with HF in the presence of chromium-type catalysts, as described in United States Patent No. 3,210,430 issued to Knight.
  • bromodifluoromethane is the combination of efficacy, low ODP and acceptable toxicity.
  • Prior art fire extinguishants typically are less desirable as to one or more of these properties. Bromodifluoromethane is therefore a superior fire extinguishant in appropriate
  • Halon 1301 are slightly more effective on a weight basis, but their ODP's are substantially higher, rendering them environmentally unacceptable.
  • bromodifluoromethane compositions of the present invention have reduced ODP ratings, but are surprisingly effective at levels safe to humans, i.e. particularly at concentrations less than about 10% (v/v).
  • the present invention provides a distinct
  • bromotrifluoromethane and bromochlorodifluoromethane thereby making it less likely to penetrate into the stratosphere, or to persist in that region. Accordingly, its potential for ozone depletion is dramatically lower than more stable compounds, such as CHF-Br, or CF 3 Br.
  • more stable compounds such as CHF-Br, or CF 3 Br.
  • bromodifluoromethane has been determined to have an ozone depletion potential less than one tenth of that of
  • the fire extinguishant compositions of this invention generally exhibit an ozone depletion potential of less than about 3.0, and preferably less than about 1.0.
  • the ODP of a pure compound may be calculated using the following algorithm developed by G. Dana Babson of the
  • ODP A E P [(#Cl) B + C(#Br)] D (#C-l)
  • P is the photolysis factor.
  • the Babson method provides a reasonable approximation of the ozone depletion potential (ODP) as calculated by the more complex method described in "The Relative Efficiency of a Number of Halocarbons for Destroying Stratospheric Ozone", by D. J. Wuebbles, Lawrence Livermore Laboratory Report
  • compositions of this invention have been found to exhibit excellent fire extinguishment properties, a good combination of physical properties, such as boiling point and vapor pressure, a good combination of handling and use
  • compositions such as cleanliness and superior discharge pattern configurations, reasonable toxicity characteristics, and low ozone depletion potential.
  • Appropriate selection of the components of the composition permit utilization of existing equipment without making expensive hardware changes, and may also minimize the temperature dependency of the discharge agent, thus broadening the range of the composition's
  • mixtures of the present invention may be formulated to have a desirably low ODP or other optimized physical characteristics by
  • bromodifluoromethane compositions of the present invention provide a uniform discharge over a slightly longer discharge period than comparable fire extinguishant compositions based on bromochlorodifluoromethane (Halon 1211), despite the fact that bromodifluoromethane has a higher vapor pressure than Halon 1211 at a given temperature.
  • the bromodifluoromethane compositions also exhibit good throw characteristics, thus providing a significant advantage over bromotrifluoromethane (Halon 1301), which tends to volatilize too quickly. Because of the lower equilibrium pressure of bromodifluoromethane compositions relative to the comparable Halon 1301
  • compositions at the same temperature may be contained and discharged using containers and fittings of lower pressure rating than those required for comparable compositions based on Halon 1301.
  • bromodifluoromethane compositions provide a discharge stream more cohesive than that provided by either Halon 1211 or Halon 1301 compositions. This affords a particular advantage in efficiency.
  • a good cohesive discharge pattern can achieve quick "knock down" of fire by physically displacing high temperature combustion products and oxygen supply from the fuel. This allows the fire to be extinguished more quickly and/or with a lesser amount of fire extinguishant.
  • fire extinguishant compositions comprising
  • bromodifluoromethane alone or in combination with a
  • the fire extinguishants consist essentially of bromodifluoromethane, or of
  • bromodifluoromethane is preferably blended with a propellant gas to produce a gas and liquid phase mixture of fire extinguishant component and compatible propellant.
  • a propellant gas to produce a gas and liquid phase mixture of fire extinguishant component and compatible propellant.
  • the propellant be non-reactive, stable and non-interfering with bromodifluoromethane and that it provide suitable pressure, at moderate weight percents, to propel the bromodifluoromethane adequately into the fire for the given fire extinguishing systems and conditions.
  • gases for use in such a blend include nitrogen, carbon dioxide, trifluoromethane, carbon tetrafluoride, argon and mixtures thereof, or other gases including air.
  • extinguishant composition a wide range of blends of bromodifluoromethane and propellant gases may be suitable.
  • a composition that is effective for delivery under autogenous pressure from conventional fire extinguishing apparatus the relative proportions of
  • bromodifluoromethane and propellant are preferably such that the equilibrium pressure at 70°F of the two phase mixture is between about 45 psig and about 600 psig, and more preferably between about 100 psig and about 400 psig.
  • bromodifluoromethane and propellant into a bromodifluoromethane weight fraction of at least about 70% by weight Proportions in these ranges provide highly effective fire extinguishment qualities, including effective function over a range of ambient temperature, yet provide an ozone depletion potential that is substantially lower than common prior art compounds, including either bromotrifluoromethane or bromochlorodifluoromethane.
  • the fire extinguishing compositions comprise a mixture of bromodifluoromethane and a fluorocarbon fire extinguishant.
  • the fluorocarbon fire extinguishant may comprise any of a wide variety of known, fluorine-containing compounds which form stable, efficacious mixtures with
  • fluorocarbon fire extinguishants typically are those effective at less than about 12% (v/v).
  • fluorocarbons include
  • bromotrifluoromethane bromochlorodifluoromethane
  • chlorodifluoromethane chlorotrifluoromethane
  • bromodifluoromethane may be used as a partial replacement for halogenated hydrocarbons otherwise used in fire extinguishing compositions.
  • bromodifluoromethane may be added thereto to form a fire extinguishant mixture.
  • bromodifluoromethane may be used to partially or fully substitute for one of thoso components. This has the advantage of modifying the overall characteristics of the prior art fire extinguishant
  • Bromodifluoromethane is therefore seen to be extremely flexible in its manner of use in preparing mixtures for use as fire extinguishants.
  • the relative amounts of the bromodifluoromethane and fluorocarbons mixed therewith are not critical, but rather are dictated by the characteristics desired for the overall composition. Thus, certain applications may require lower toxicity, while other instances may call for maximized efficacy. Therefore, no particular ratios of compounds are required.
  • mixtures according to the present invention are those which have at least about a 10% increase in fire extinguishing efficiency over the predicted efficiency for the weighted average of the two components.
  • Effective mixtures for fire extinguishment may be prepared by mixing bromodifluoromethane with a variety of known fire extinguishing agents, such as Halon 1301 (CF 3 Br), Halon 1211 (CF 2 BrCl), Halon 1202 (CF 2 Br 2 ) or Halon 2402
  • Such mixtures optionally include a
  • propellant such as nitrogen, carbon dioxide, trifluoromethane (CF 3 H), tetrafluoromethane (CF 4 ) or argon.
  • compositions which include bromochlorodifluoromethane preferably have an ozone depletion potential of less than about 1.5 and contain between about 5% and about 35% by weight bromochlorodifluoromethane.
  • Compositions which include bromotrifluoromethane preferably have an ozone depletion potential (calculated by the Babson method) of less than about 3.0 and contain between about 0.9% and about 15% by weight bromotrifluoromethane.
  • hydrofluorocarbons such as CF 3 CHFCF 3 , CF 3 CF 2 CF 2 H,
  • the compounds since the compounds contain hydrogen atoms, they are susceptible to breakdown in the lower atmosphere and hence do not pose a threat as greenhouse warming gasses. Mixtures of CHF 2 Br and heptafluoropropane are especially preferred because the compounds have similar vapor pressures over a wide range of temperatures and therefore the composition of the mixture remains relatively constant during discharge or other application.
  • hydrofluorocarbons of this type are compounds of the formula C X H Y F Z , where x is 2 or 3; y is 1 or 2; and z is 5, 6 or 7; where y is 1 and z is 5 when x is 2; and where z is 6 or 7 when x is 3.
  • Hydrofluorocarbons in this class include heptafluoropropane (CF 3 CHFCF 3 ),
  • hydrofluorocarbon compounds are non-toxic and are economical to manufacture.
  • HF anhydrous HF
  • Pentafluoroethane may be obtained by the addition of hydrofluoric acid to
  • hydrofluorocarbons desirably include the hydrofluorocarbon at a level of at least about 10 percent by weight of the blend.
  • the use of hydrofluorocarbons at higher levels in such blends further minimizes the ODP and resultant adverse environmental effects.
  • ozone depletion potential of less than about 0.9 and contain between about 5% and about 90% by weight hydrofluorocarbon.
  • Heptafluoropropane having a boiling point of about -17°C, is highly miscible with bromodifluoromethane. Consequently, mixtures may contain substantially any proportion of heptafluoropropane to bromodifluoromethane.
  • Such compositions preferably include between about 1% and about 99% by weight heptafluoropropane.
  • the ODP for compositions including heptafluoropropane is preferably below about 0.9.
  • Effective extinguishing compositions are also prepared by mixing bromodifluoromethane with a hydrochlorofluorocarbon such as CF 3 CHFCl, CF 2 HCF 2 Cl, CF 3 CHCl 2 or CHF 2 Cl,
  • compositions containing optionally in the presence of a compatible propellant such as nitrogen, trifluoromethane, carbon tetrafluoride, argon or carbon dioxide.
  • a compatible propellant such as nitrogen, trifluoromethane, carbon tetrafluoride, argon or carbon dioxide.
  • hydrochlorofluorocarbons preferably have an ODP of less than about 0.9, and contain about 5% to 90% by weight
  • CFC 124 2-Chloro-1,1,1,2-tetrafluoroethane (CF 3 CHFCl), a halogenated hydrocarbon also known as CFC 124.
  • CFC 124 2-Chloro-1,1,1,2-tetrafluoroethane
  • concentration employed may depend to some extent on the nature of the fire, the combusting material and the circumstances of application.
  • the similarity of boiling points for the two compounds allows the composition discharged or otherwise applied to remain essentially constant.
  • Blends having from about 5% to about 99% by weight CFC 124 and from about 95% to about 1% by weight bromodifluoromethane are particularly preferred.
  • 2-Chloro-1,1,1,2-tetrafluoroethane is that the mixtures are especially attractive due to their low ODP.
  • 2-Chloro-1,1,1,2-tetrafluoroethane has an ODP of 0.03 as calculated by the Babson model. It is believed that the presence of the hydrogen in 2-Chloro-1,1,1,2-tetrafluoroethane makes the compound less stable and contributes to the lower ODP, since the molecules are susceptible to breakdown in the lower atmosphere.
  • a consideration in selecting a concentration for the compositions of this invention is the maintenance of the area in a non-toxic and non-anesthetic condition.
  • a 50% lethal concentration (LC50) for a compound is that concentration of the compound (volume of compound per volume of air) at which 50% of a test population is killed; a 50% anesthetic dose (AD 50) is that concentration at which 50% of a test population is anesthetized.
  • LC50 lethal concentration
  • AD 50 anesthetic dose
  • 2-Chloro-1,1,1,2-tetrafluoroethane has an LC50 of 44.7% v/v, and an AD50 of 15.5% v/v, as
  • a usage rate where humans may be present is preferably below about 15% v/v, and more preferably below about 10% v/v.
  • Mixtures are also provided in the present invention which comprise bromodifluoromethane and a selected fluorocarbon component, all as previously described, and a third component comprising a propellant.
  • a propellant may be any which is compatible and useful in combination with the other
  • propellants include nitrogen, carbon dioxide, trifluoromethane, carbon tetrafluoride and argon.
  • Other compatible propellants or other compounds may also be mixed with the fire extinguishants of the present invention.
  • compositions containing a non-fluorocarbon propellant such as nitrogen, argon or carbon dioxide are preferred.
  • a non-fluorocarbon propellant such as nitrogen, argon or carbon dioxide
  • propellants nitrogen is particularly advantageous because it provides a favorable balance of reasonable cost and low dielectric constant.
  • Carbon dioxide is also advantageous from a cost standpoint, but is less preferred in applications where conductivity of the fire extinguishing agent is or may be a problem.
  • Compositions containing such non-fluorocarbon propellants preferably have a low proportion of propellant, typically in the range of 0.1% to 5% by weight.
  • compositions typically exhibit an ozone depletion potential of less than 1.0.
  • the bromodifluoromethane compositions blended with a propellant gas produce a gas and liquid phase mixture of fire extinguishant component and propellant.
  • a wide range of blends of bromodifluoromethane compositions and propellant gases may be suitable.
  • the relative proportions of bromodifluoromethane composition and propellant are such that the equilibrium pressure of the two phase mixture at 70°F is preferably between about 45 psig and about 600 psig, and more preferably between about 100 psig and about 400 psig. Higher pressures can be used, although there will be an increase in equipment costs.
  • extinguishants such as bromotrifluoromethane or
  • compositions of the invention are mixtures containing bromodifluoromethane, nitrogen, and one of the following: Halon 1211, Halon 1301, heptafluoropropane and CFC 124.
  • the ratios of the components are as already described.
  • the nitrogen content is typically between about 0.3% and about 10% by weight.
  • the nitrogen content is typically between about 0.1% and about 10% by weight.
  • compositions of the invention include those formulated for replacement of Halon 1211 and Halon 1301 in existing systems.
  • Compositions adapted to replace Halon 1211 e.g., in hand held fire extinguisher applications, preferably are formulated to have a phase equilibrium pressure of between about 100 psig and about
  • compositions adapted to replace Halon 1301, typically in large stationary flooding systems preferably are formulated to have a phase equilibrium pressure of between about 300 psig and about 400 psig at 70°F.
  • the bromodifluoromethane compositions may be applied in the variety of ways employed for other halogenated hydrocarbon extinguishants, including application in flooding systems, specialized systems and portable systems, described hereafter in more detail.
  • the methods for application of the described fire extinguishing compositions include those known to be useful for other halogenated hydrocarbons, such as Halon 1211 and Halon 1301. In broad terms, these methods utilize
  • a system may also contain other elements, such as one or more detectors, remote and local alarms, a piping network, mechanical and electrical interlocks to shut down ventilation, etc., directional control valves, etc.
  • Such systems may be stationary or portable, and typically the fire extinguishant may be pressurized with propellant gas at up to about 600 psig at ambient temperature.
  • Figure 1 there is shown a typical system for a room 11 having a raised floor 12 and ceiling 13.
  • Automatic fire detectors 14 are installed in the ceiling and floor and activate the fire extinguishing system when needed.
  • the extinguishing system comprises storage tanks 15, piping 16 and discharge nozzles 17.
  • a control panel 18 operatively connects the detectors with the fire extinguishing system to activate it.
  • compositions of the present invention may be used in a total flooding fire extinguishing system in which the agent is introduced to an enclosed region (e.g., a room or other enclosure) to surround a fire at a concentration
  • Total flooding systems are used, for example, for computer rooms, control rooms, special storage areas, machinery spaces and the like. In a total flooding system apparatus, equipment or even rooms or
  • enclosures may be provided with a source of agent and
  • Local application systems discharge fire extinguishing agent in such a manner that the burning object is surrounded locally by a high concentration of agent to extinguish the fire.
  • Local systems are often employed because the enclosure may not be suitable to provide for total flooding. Examples include use for presses, tanks, spray booths, and electric transformers.
  • compositions of the present invention can be conveniently employed in local application systems through the use of conventional portable fire
  • extinguishing equipment such as those described in the Fire Protection Handbook.
  • the supply of fire extinguishing agent is typically directed by hand at the fire, or larger mobile units with hoses and nozzles are employed for directional spraying. It is usual to increase the pressure in portable fire extinguishers with suitable propellant gases in order to insure that the agent is completely expelled from the extinguisher.
  • Systems in accordance with this invention may be conveniently pressurized at any desirable pressure up to about 600 psig at ambient conditions.
  • extinguishant composition is discharged into the combustion zone of a fire for a time sufficient to suppress the fire.
  • amount of extinguishant applied may desirably be enough to fully extinguish or simply to suppress the fire.
  • the fire may be limited to a controllable volume, and thereafter be fully extinguished with additional use of the
  • bromodifluoromethane compositions or with other extinguishant materials or methods are used or with other extinguishant materials or methods.
  • fire fighting efficacy of the bromodifluoromethane will be usefully employed, and as used herein the term "extinguishing amount" encompasses both suppression and extinguishment.
  • Minimum concentrations employed may be substantially any at which a given fire may be suppressed or extinguished, the exact minimum level being dependent on the nature of the fire, the combusting material, the particular extinguishant
  • compositions are present at a level of at least about 2% (v/v), and more preferably at least about 4% (v/v).
  • the maximum amount to be employed will be governed by matters such as economics and potential toxicity to living things. About 15% (v/v) provides a convenient maximum
  • concentration for the compositions in occupied areas may be employed in unoccupied areas, with the exact level again being determined by the particular combustible material, the
  • compositions in accordance with this invention are in the range of about 4% to about 10% (v/v).
  • the extinguishant composition within the container is a liquid and gas phase mixture of the fire extinguishant components and propellant having an equilibrium pressure typically of about 45 psig to 600 psig, preferably about
  • the initial composition within the container is preferably such that a substantial pressure is maintained as long as there is any significant residue of liquid phase within the container. A substantial pressure should be maintained until an effective amount of
  • FIG. 2 Illustrated schematically in Figure 2 is a portable fire extinguisher which includes a cylinder 21 containing a
  • bromodifluoromethane composition is maintained at a pressure of 45 to 600 psig, preferably 100 to 200 psig, at ambient temperatures contemplated for use in fighting fires.
  • An amount of extinguishant is provided as will be sufficient for blanketing a fire, and thereby extinguishing it or suppressing it to a controllable level.
  • the charge is a gas and liquid phase mixture which is substantially at equilibrium at the aforesaid pressure and ambient temperature.
  • a discharge valve 25 operated by a trigger mechanism 27 provides for release of the fire extinguishant composition from the container, and a discharge horn 29 is adapted to direct the extinguishant to the combustion zone of the fire.
  • the extinguisher discharge valve may be fitted with a hose and spray nozzle for direction of the
  • extinguisher system triggering devices There are four basic types of extinguisher system triggering devices: manual (such as a pull pin), thermatic (similar to a heat activated sprinkler head), electronic (activating a solenoid), and rupture disc. Discharge temperatures typically range from -40° to 120°F (50°C). Large stationary or mobile systems typically also include means such as a filling valve for charging the system with fire extinguishant.
  • the mixtures of the invention may be delivered from a single cylinder or other suitable container containing the bromodifluoromethane and the adjuvant, and optionally also containing a propellant.
  • the components may be stored in separate containers and premixed through common piping or mixture devices prior to delivery to the fire.
  • any desired blend may be effectively delivered to the fire.
  • Fire extinguishant compositions of the present invention were prepared by combining bromodifluoromethane and nitrogen in the proportions shown in nos. B-1, B-2 and B-3 in Table 1. These compositions have low ODP, suitable phase equilibrim pressure for use in conventional systems, and are effective fire extinguishants. Similar mixtures of bromodifluoromethane with carbon dioxide, argon and carbon tetrafluoride yield similarly good compositions.
  • compositions were prepared by combination of bromodifluoromethane, nitrogen and either of Halon 1211 (H-1211) or Halon 1301 (H-1301).
  • compositions listed as T-1 through T-6, also provide
  • Test systems were prepared by filling containers with the compositions set forth in Table 2. In each case the test container was filled about half way on the basis that this would be the minimum fill for a commercial system, maximizing the propellant content. Table 2 also indicates the phase equilibrium pressure exhibited by each composition at 70°F. These compositions perform well as extinguishing materials in terms of discharge and efficacy.
  • Bromodifluoromethane vapor was mixed with air and introduced to a flame produced in a glass cup burner, with the concentration of bromodifluoromethane being slowly increased until the flow was just sufficient to cause extinction of the flame.
  • the data are reported in Tables 3-5, which also show the amount of bromodifluoromethane required on a weight basis. Extinguishing concentrations, % v/v were calculated from the relationship
  • bromodifluoromethane is seen to be more efficient on a weight basis than Halon 1211 for the extinguishment of typical Class B type fuels.
  • Bromodifluoromethane (9 pounds) was charged into an Ansul Model SY 0941 portable extinguisher and sufficient nitrogen added to bring the total cylinder pressure to 125 psig.
  • Halon 1211 (CF2BrCl, 9 pounds) was charged into an identical extinguisher and pressurized with nitrogen to a total of 125 psig. Discharge testing was conducted in accordance with Section 26 of UL Standard 1093, and results are shown in Table 6.
  • bromodifluoromethane was charged at 195 psig (with nitrogen) to an Amerex 1211 extinguisher having an orifice smaller than the Ansul unit, and provided with a short discharge horn.
  • a cupola with adjustable louvers to control drafting conditions was mounted on the top of the roof.
  • Halon 1211 criteria for approval of Halon 1211 for this application.
  • the system was charged with CHF2Br or Halon 1211 and pressurized with nitrogen to 150 psig. All trials were conducted outdoors by discharging the fire extinguishant agent through varying piping configurations into enclosed boxes of varying size.
  • bromodifluoromethane composition was judged to be as good as that of the bromochlorodifluoromethane composition, both in balanced and unbalanced systems. No trials were made to determine the effect of nozzle design on discharge of the CHF 2 Br composition, but nozzle coverage was judged better than that afforded by Halon 1211. Both products mixed well in the test box enclosure. No equipment or valve problems were noted.
  • HX decomposition products
  • Decomposition products were determined by a procedure similar to that described by Sheinson, et al., in Fire &.
  • This example demonstrates the efficacy of blends of bromodifluoromethane with hydrofluorocarbons.
  • Various mixtures of bromodifluoromethane and a hydrofluorocarbon were tested with n-heptane fuel in a cup burner apparatus as described in Example 3, and the results are shown in Tables 10-13.
  • % added to air (cc of agent/cc of air) x 100.
  • Tables 10-13 the volume percents of each agent and the total volume percent of the mixture at extinguishment, and the concentrations of each agent and the total concentration on a weight basis (mg/L) at extinguishment.
  • the Tables also illustrate the range of ODP values obtainable with the various mixtures.
  • the ODP of a given mixture is calculated as the sum of the weight percent of each agent multiplied by its ODP, as calculated by the Babson method. For example a 50:50 (by weight) blend of CHF2Br and CF3Br has an ODP of
  • Blends of CHF2Br with CF3H are particularly useful, and a large synergistic effect is observed.
  • a 52:48 by mole mixture of CHF 2 Br and CF3H affords a 34 % reduction in ODP, with only a 1 % increase in the total weight of agents required for extinguishment.
  • the total weight of agents required is actually less than that required for either pure agent.
  • the present invention provides compositions which release from a contained charge in a uniform, cohesive stream over a sustained period.
  • the compositions yield the distinctive throw characteristics with utilization in existing fire extinguishing equipment with little or no modification to the equipment required.
  • the discharge patterns achieved with the inventive compositions impact the ability to obtain quick "knock down" of a fire, which in turn will affect the amount of extinguishant required to extinguish a given fire.
  • the fire extinguishing systems containing the inventive compositions include means for sealing the components thereof against leakage.
  • Elastomers used in gaskets and O-rings, for example, are vital to assure proper containment and discharge of an extinguishant. It has been found that there is a distinct difference in compatibility of elastomers with bromodifluoromethane, as opposed to other fire extinguishants such as bromochlorodifluoromethane and bromotrifluoromethane.
  • bromodifluoromethane compositions preferably include
  • EPDM ethylene propylene diene terpolymer
  • elastomers will in general be those which have dissimilar solubility parameters. Solubility parameters for certain identified fire extinguishants and elastomers are listed in Table 19, and are consistent with observations as to elastomer compatibility, particularly when it is taken into consideration the range of polymers which can be produced within each classification.
  • compatible elastomers will generally be those which are non-polar and are therefore less susceptible to attack from the more polar bromodifluoromethane (as
  • bromochlorodifluoromethane bromochlorodifluoromethane
  • the more polar elastomers such as acrylonitrile-butadiene copolymers (nitrile rubber, Buna-N) are suitable for use with Halon 1211 and Halon 1301, but are not desirable for use with the
  • FIG. 3 schematically shows the detail of a connection between a container and discharge valve in an extinguisher of the type depicted in Fig. 2.
  • a nozzle 31 at the top of the container 21 comprises a flange 33 having a circular groove 35 in its face concentric with the nozzle.
  • a flange 37 on discharge valve 25 also has a circular groove 39 that matches the groove in flange 33 to define a space for receipt of an O-ring gasket 41 that seals the connection.
  • These preferred sealing materials are stereospecific linear terpolymers of ethylene, propylene and small amounts of a nonconjugated diene, for example a cyclic or aliphatic diene such as hexadiene, dicyclopentadiene, or ethylidene
  • the polymers are vulcanized with conventional vulcanizing materials.
  • EPDM rubber is an especially preferred sealing material.
  • a linear swell of 4.7% is generally considered acceptable in a gasket material, but a linear swell of over 5% is considered unacceptable. Accordingly, it may be seen that, of the various gasket materials tested, only the EPDM materials were found to be feasibly useful in a commercial fire extinguisher.

Abstract

On décrit des procédés, des compositions et des systèmes extincteurs de feu efficaces et présentant de risques minimes pour l'environnement. Lesdits procédés utilisent des compositions comportant du bromodifluorométhane seul ou en combinaison avec au moins un autre élément extincteur à fluorocarbone. Un nombre important des mélanges extincteurs montre une efficacité synergique contre l'incendie, des fluorocarbones représentatifs et utilisables avec ledit bromodifluorométhane étant le bromotrifluorométhane, le bromochlorodifluorométhane, l'heptafluoropropane, 1,1,1,2,3,3-hexafluoropropane, 1,1,1,3,3,3-hexafluoropropane, le pentafluoroéthane, 2-chloro-1, 1,1,2-tétrafluoroéthane, dibromodifluorométhane, dibromotétrafluoroéthane, chloropentafluoroéthane, 2-bromo-1,1,1,2-tétrafluoroéthane, C2F6, C3F8, C4F10, 1-bromo-1,1,2,2-tétrafluoroéthane, 1-chloro-1,1,2,2-tétrafluoréthane et des mélanges de ceux-ci. De plus, on peut utiliser un propulseur compatible. On décrit également lesdites compositions et des systèmes chargés de celles-ci. Les compositions se caractérisent en ce qu'elles présentent une efficacité surprenante contre l'incendie, une toxicité et un potentiel de déplétion d'ozone faibles, ainsi qu'un rendement minimal de produits de décomposition nuisibles à la santé.
EP90915893A 1989-10-10 1990-10-10 Compositions extinctrices de feu, procedes et systemes utilisant du bromodifluoromethane Withdrawn EP0447538A1 (fr)

Applications Claiming Priority (8)

Application Number Priority Date Filing Date Title
US41913289A 1989-10-10 1989-10-10
US419132 1989-10-10
US07/439,738 US5124053A (en) 1989-08-21 1989-11-21 Fire extinguishing methods and blends utilizing hydrofluorocarbons
US07/488,295 US5113947A (en) 1990-03-02 1990-03-02 Fire extinguishing methods and compositions utilizing 2-chloro-1,1,1,2-tetrafluoroethane
US488295 1990-03-02
US56169090A 1990-08-01 1990-08-01
US561690 1990-08-01
US439738 1999-11-15

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EP (1) EP0447538A1 (fr)
JP (1) JPH06500240A (fr)
CN (1) CN1051513A (fr)
AU (1) AU6615290A (fr)
CA (1) CA2027273A1 (fr)
CS (1) CS490890A3 (fr)
HU (1) HU911909D0 (fr)
IL (1) IL95894A0 (fr)
WO (1) WO1991005585A1 (fr)

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FR2662947A1 (fr) * 1990-06-08 1991-12-13 Atochem Utilisation d'une composition a base d'halogenoalcanes comme agent extincteur.
US5080177A (en) * 1990-07-26 1992-01-14 Great Lakes Chemical Corporation Fire extinguishing methods utilizing 1-bromo-1,1,2,2-tetra-fluoroethane
US5538659A (en) * 1993-03-29 1996-07-23 E. I. Du Pont De Nemours And Company Refrigerant compositions including hexafluoropropane and a hydrofluorocarbon
MY132201A (en) * 1995-02-03 2007-09-28 Great Lakes Chemical Corp Method and system for delivering a fire suppression composition to a hazard
US10343003B2 (en) 2014-10-02 2019-07-09 The Boeing Company Aircraft fire suppression system and method
US10653904B2 (en) 2017-12-02 2020-05-19 M-Fire Holdings, Llc Methods of suppressing wild fires raging across regions of land in the direction of prevailing winds by forming anti-fire (AF) chemical fire-breaking systems using environmentally clean anti-fire (AF) liquid spray applied using GPS-tracking techniques
US11395931B2 (en) 2017-12-02 2022-07-26 Mighty Fire Breaker Llc Method of and system network for managing the application of fire and smoke inhibiting compositions on ground surfaces before the incidence of wild-fires, and also thereafter, upon smoldering ambers and ashes to reduce smoke and suppress fire re-ignition
US11865390B2 (en) 2017-12-03 2024-01-09 Mighty Fire Breaker Llc Environmentally-clean water-based fire inhibiting biochemical compositions, and methods of and apparatus for applying the same to protect property against wildfire
US11865394B2 (en) 2017-12-03 2024-01-09 Mighty Fire Breaker Llc Environmentally-clean biodegradable water-based concentrates for producing fire inhibiting and fire extinguishing liquids for fighting class A and class B fires
US11826592B2 (en) 2018-01-09 2023-11-28 Mighty Fire Breaker Llc Process of forming strategic chemical-type wildfire breaks on ground surfaces to proactively prevent fire ignition and flame spread, and reduce the production of smoke in the presence of a wild fire
CN112190866A (zh) * 2019-07-08 2021-01-08 上海汇友精密化学品有限公司 一种六氟丙烷混合灭火剂及其制备方法
US11911643B2 (en) 2021-02-04 2024-02-27 Mighty Fire Breaker Llc Environmentally-clean fire inhibiting and extinguishing compositions and products for sorbing flammable liquids while inhibiting ignition and extinguishing fire
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IL95894A0 (en) 1991-07-18
CS490890A3 (en) 1992-02-19
HU911909D0 (en) 1991-12-30
AU6615290A (en) 1991-05-16
WO1991005585A1 (fr) 1991-05-02
CN1051513A (zh) 1991-05-22
CA2027273A1 (fr) 1991-04-11
JPH06500240A (ja) 1994-01-13

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