Classifications

• • A—HUMAN NECESSITIES
  • A62—LIFE-SAVING; FIRE-FIGHTING
  • A62C—FIRE-FIGHTING
  • A62C99/00—Subject matter not provided for in other groups of this subclass
  • A62C99/0009—Methods of extinguishing or preventing the spread of fire by cooling down or suffocating the flames
  • A62C99/0018—Methods of extinguishing or preventing the spread of fire by cooling down or suffocating the flames using gases or vapours that do not support combustion, e.g. steam, carbon dioxide
• • 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 extinguishing compositions and methods, and particularly to compositions and methods employing compositions comprised of hydrofluorocarbons and acid scavenging additives.
• bromine-containing compounds are effective fire fighting agents, those agents containing bromine or chlorine are asserted to be capable of the destruction of the earth's protective ozone layer.
• Halon 1301 has an Ozone Depletion Potential (ODP) rating of 10
• Halon 1211 has an ODP of 3.
• hydrofluorocarbons as extinguishing agents has been proposed only recently, for example as described in U.S. Patent 5,124,053 to Iikubo and Robin. Since the hydro luorocarbons do not contain bromine or chlorine, the compounds have no effect on the stratospheric ozone layer and their ODP is zero. It has been discovered that certain of these compounds, especially those with a higher ratio of hydrogen to fluorine in the molecule, can decompose to some extent in a fire, producing hydrogen fluoride, HF, which is potentially damaging to personnel and equipment if formed in large quantities.
• a method of extinguishing a fire that comprises introducing to the fire a fire extinguishing concentration of an extinguishant composition comprising, and preferably consisting essentially of, a hydrofluorocarbon and an acid-scavenging additive, and maintaining the concentration of the composition until the fire is extinguished.
• Fire extinguishing compositions comprising, or consisting essentially of, a hydrofluorocarbon and an acid-scavenging additive are also provided.
• a further object of the present invention is to provide fire extinguishing compositions comprising blends of hydrofluorocarbons and acid-scavenging additives, which blends are effective and safe in use.
• a further object of the present invention is to provide fire extinguishing compositions which produce reduced amounts of decomposition products compared to other fire extinguishing agents when employed in the extinguishment of fires.
• compositions comprising a hydrofluorocarbon in combination with an acid-scavenging additive provide particularly effective fire extingiiishants at concentrations safe for use. Because the compositions contain no bromine or chlorine, they have an ozone depletion potential of zero.
• compositions produce less decomposition products than the hydrofluorocarbon analogs, and hence are of reduced toxicity with regard to use in a fire scenario.
• the invention relates to methods for extinguishing fires which are improved by using these compositions as the fire extinguishing agents.
• extinguishant compositions may preferably consist essentially of the hydro luorocarbon and the acid-scavenger(s) .
• hydrofluorocarbons useful in accordance with the present invention include trifluoromethane (CF-H), pentafluoroethane (CF CF II) , 1, 1, 1,2-tetrafluoroethane (CF 3 CH 2 F) , 1,1, 1,2,3,3-hexafluoropropane (CF 3 CHFCF 2 H) , 1, 1,1,3,3,3-hexafluoropropane (CF CH CF ) , 1, 1,2,2,3,3-hexafluoropropane (HCF 2 CF 2 CF 2 H) , 1,1, 1,2, 3,3, 3-heptafluoropropane (CF 3 CHFCF_) , 1,1, 1, 2,2,3,3-heptafluoropropane (CF CF.CF H) , 1,1, 1,2,2,3,3,4,4-nonafluorobutane (CF 3 CF 2 CF 2 CF 2 II) , 1, 1,1,2,3,4,4, -octafluorobutane
• hydrofluorocarbons within the present invention are C 3 H 3 F 5 , C 4 I. 3 F 7 . 5 HF 3 F ⁇ , C ⁇ F ⁇ , C 5 H 3 F 9 , C 5 H 4 F B . and C ⁇ I ⁇ .
• Specific terpenes useful in accordance with the present invention include citral, citronellal, limonene, dipentene, menthol, alpha-pinene, beta-pinene, camphor, vitamin A beta-carotene, and isopro ⁇ enyl-1-methylcyclohexene.
• the terpenes preferably comprise from about 0.1% to about 10% by weight of the extinguishing composition.
• Specific unsaturated oils useful in accordance witli the present invention include oleic acid, linoleic acid, palinitoleic acid and vaccenic acid.
• the unsaturated oils preferably comprise from about 0.1% to about 10% by weight of the extinguishing composition.
• alkali metal halides useful in accordance with the present invention include sodium chloride, potassium chloride, sodium bromide and potassium bromide.
• the alkali metal halides preferably comprise from about 0.1% to about 10% by weight of the extinguishing composition.
• a method for extinguishing fires which includes the use of a composition comprised of a hydrofluorocarbon and an acid-scavenging additive as a fire ext nguishing agent.
• the compositions may be applied in the variety of methods employed for other halogenated hydrocarbons, including application in a flooding system, portable system or specialized system.
• the extinguishant is effective in low concentrations, and of course, at high concentrations as well.
• the concentration employed may depend to some extent on the nature of the fire, the combusting material and tiie circumstances of application.
• application rates preferably range from about 1% to about 25% v/v, and more preferably from about 2% and to about 15% v/v, of the hydrofluorocarbon component in the atmosphere.
• the acid-scavenging additives comprise from about 0.1% to about 10% by weight of the composition.
• the relative amounts of the hydrofluorocarbon and the acid-scavenging additive are not critical, but rather are dictated by the characteristics desired for the overall composition. For example, in certain applications there may be a greater need for low toxicity, and in other instances, the emphasis may be on cleanliness of the extinguishment .
• the methods for application of the described fire extinguishing compositions are those known to be useful for the Halon agents. In broad terms, these methods utilize application systems which typically include a supply of agent, a means for releasing or propelling the agent from its container, and one or more discharge nozzles to apply the agent into the hazard or directly onto the burning object.
• the agents of this invention may be used in total flooding systems in which the agent is introduced into an enclosed region surrounding a fire at a concentration sufficient to extinguish the fire.
• equipment or even rooms may be provided with a source of agent and appropriate piping, valves and controls so as to automatically and/or manually be introduced at appropriate concentrations in the event that fire should break out.
• the fire extinguishant may be pressurized with nitrogen or other inert gas at up to about 600 psig at ambient conditions.
• compositions of the invention may be applied to a fire through the use of conventional portable fire extinguishing equipment. It is usual to increase the pressure in portable fire extinguishers with nitrogen or other inert gases in order to ensure that the agent is completely expelled from the extinguisher. Systems in accordance witli this invention may be conveniently pressurized at any desirable pressure up to about 600 psig at ambient conditions.
• EXAMPLE 1 A test facility with a total internal volume of 1440 cubic feet was constructed from 2x4 lumber and 3/4" plywood. The enclosure was equipped with two 3 foot by 3 foot windows and two standard doors located on opposite walls. The delivery system consisted of a standard Halon cylinder connected to 1" carbon steel pipe via a stainless steel flexhose, terminating in a standard Halon nozzle located 6 inches down from the center of the ceiling.
• a large steel pan was filled with commercial n-heptane and placed in the center of the facility, and the n-heptane was then ignited. Thirty seconds after ignition, the doors to the enclosure were closed and the extinguishing agent released.
• the enclosure atmosphere was sampled after extinguishment of the fire by pulling a sample of the post-extinguishment atmosphere through a buffer solution contained in a polypropylene bubbler equipped with a 70 micron porous polyethylene frit. Fluoride and HF concentrations were determined employing a fluoride ion selective electrode (ISE).
• the post-extinguishment atmosphere was sampled at two locations, one at a height of 6 feet and the second at a height of 2 feet, both sampling points located 2 feet diagonally out from the corner of the enclosure.
• Example 2 The procedure of Example 1 was repeated employing G9 pounds of 1, 1, 1,2, 3,3 ,3-heptafluoropropane (CF CHFCF ) to which had been added 1.0 pounds of dipeutene (1.4 % by weight) . Analysis showed the concentration of HF to be 2403 ppm at the 6 foot location and 1202 ppm at the 2 foot location.
• CF CHFCF 1, 1, 1,2, 3,3 ,3-heptafluoropropane
• This example demonstrates the advantageous effect of the addition of a small amount of an acid-scavenging additive to the hydrofluorocarbon.
• the amount of HF produced was reduced by 32% at the 6 foot location and by 38% at the 2 foot location.
• Example 3 The procedure of Example 1 was repeated employing a small steel pan filled with n-heptane. Analysis of the post-extinguishment atmosphere showed a concentration of HF of 50 ppm at the 6 foot location and 11 ppm at the 2 foot location.
• EXAMPLE 4 The procedure of Example 3 was repeated employing 69 pounds of 1, 1,1,2,3,3,3-heptafluoropropane (CF-CHFCF..,) to which had been added 1.0 pounds of limonene (1.4 % by weight) . Following extinguishment of the fire, analysis showed the concentration of HF to be 32 ppm at the 6 foot location and 7 ppm at the 2 foot location.
• CF-CHFCF.. 1, 1,1,2,3,3,3-heptafluoropropane
• This example demonstrates the advantageous effect of the addition of a small amount of an acid-scavenging additive to the hydrofluorocarbon.
• the amount of HF produced was reduced by 36% at botli locations.
• Desirable results are achieved for combinations of 90% to 99.9% by weight of the 1, 1, 1 , 2,3,3 , 3-heptafluoropropane and of 0.1% to 10.0% of the acid-scavenger.
• suitable results are obtained for fire extinguishant compositions comprising blends of the foregoing ac d-scavengers and the various other hydrofluorocarbons defined herein, including for example, trifluoromethane, pentafluoroethane, 1,1,1, 2-tetrafluoroethane, 1,1,1,2,3,3-hexafluoropropane, 1,1,1,3,3,3-hexafluoropropane, 1,1,2,2,3, 3-hexafluoropropane, 1,1,1,2,2,3 ,3-heptafluoropropane, 1,1,1,2,2,3,3,4,4-nonafluorobutane, 1,1,1,2,3,4,4,4-octafluorobutane and 1, 1, 1, 1,3,3,

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• Business, Economics & Management (AREA)
• Emergency Management (AREA)
• Health & Medical Sciences (AREA)
• Public Health (AREA)
• Chemical & Material Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• General Chemical & Material Sciences (AREA)
• Fire-Extinguishing Compositions (AREA)

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Cited By (14)

Citations (6)

• 1995
  • 1995-03-21 EP EP95913781A patent/EP0752900A1/en not_active Withdrawn
  • 1995-03-21 NZ NZ283089A patent/NZ283089A/en unknown
  • 1995-03-21 PL PL95316629A patent/PL316629A1/xx unknown
  • 1995-03-21 CA CA002185910A patent/CA2185910A1/en not_active Abandoned
  • 1995-03-21 WO PCT/US1995/003490 patent/WO1995026218A1/en not_active Application Discontinuation
  • 1995-03-21 MX MX9604320A patent/MX9604320A/es unknown
  • 1995-03-21 JP JP7525205A patent/JPH09510891A/ja active Pending
  • 1995-03-21 AU AU21039/95A patent/AU2103995A/en not_active Abandoned
  • 1995-03-21 HU HU9602662A patent/HU9602662D0/hu unknown
  • 1995-03-22 IL IL11308695A patent/IL113086A0/xx unknown
  • 1995-03-23 ZA ZA952385A patent/ZA952385B/xx unknown
• 1996
  • 1996-09-25 KR KR1019960705361A patent/KR970702089A/ko not_active Application Discontinuation
  • 1996-09-26 NO NO964046A patent/NO964046L/no unknown

Patent Citations (6)

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