Fire extinguishing mixtures, methods and systems

<u style="single">TECHNICAL FIELD</u>

The present invention relates generally to the field of fire extinguishment, prevention, and suppression. More particularly the present invention relates to fire extinguishing mixtures, methods, and systems.

<u style="single">BACKGROUND OF THE INVENTION</u>

There are a multitude of known fire extinguishing agents, and methods and systems for using the same. The mechanism by which these fire extinguishing agents extinguish a fire can vary from agent to agent. For instance, some fire extinguishing agents operate by inerting or diluting mechanisms that act to deprive the fire of necessary chemicals, such as oxygen or fuels. Other fire extinguishing agents operate chemically to extinguish a fire. Such chemical actions may include scavenging free radicals, thereby breaking the reaction chain required for combustion. Still, other fire extinguishing agents operate thermally to cool the fire.

Traditionally, certain bromine-containing compounds such as Halon 1301 (CF₃Br), Halon 1211 (CF₂BrCl), and Halon 2402 (BrCF₂CF₂Br) have been used as fire extinguishing agents for the protection of occupied rooms. Although these Halons are effective fire extinguishing agents, some believe that they are harmful to the earth's protective ozone layer. As a result, the production and sale of these agents has been prohibited.

Relatively recently, fluorocarbons such as hydrofluorocarbons, fluoroethers and fluorinated ketones have also been proposed as effective fire extinguishing agents. Fluorocarbon systems maybe relatively inefficient and can be high in cost. In addition, some fluorocarbon fire extinguishing agents may react in the flame to form various amounts of decomposition products, such as HF. In sufficient quantities, HF is corrosive to certain equipment and poses a significant health threat.

In addition to fluorocarbon agents, inert gases have been proposed as replacements for the Halon fire extinguishing agents. Gases such as nitrogen or argon, and also blends, such as a 50:50 blend of argon and nitrogen have been proposed. These agents can be relatively inefficient at fire extinguishing, and as a result, significant amounts of the gas are necessary to provide extinguishment. The large amounts of gases required for extinguishment results in the need for a large number of storage cylinders to store the agent, and ultimately, large storage rooms to house the gas storage cylinders.

Hybrids of fluorocarbons and gas blends have also been proposed as fire extinguishing agents. For example, <patcit id="pcit0001" dnum="US6346203B"><text>U.S. Patent No. 6,346,203 to Robin et al</text></patcit>. proposes delivering to the fire gas and fluorocarbon fire extinguishing agents.

Finally, water mists have also been used for the suppression of compartment fires. Hybrid fire extinguishing systems utilizing a water mist followed by the application of either fluorocarbon or gas agents have been proposed.

It would be desirable to develop improved fire extinguishing agents and systems.

<u style="single">SUMMARY OF THE INVENTION</u>

In one aspect, the present invention provides fire extinguishing mixtures that include a diluent gas and an extinguishing compound such as fluoroethers, bromofluorocarbons, fluoroketones, and/or mixtures thereof.

Another aspect of the present invention provides a fire extinguishing mixture comprising water, a diluent gas, and an extinguishing compound that includes fluorocarbons such as hydrofluorocarbons, fluoroethers, bromofluorocarbons, fluoroketones and/or mixtures thereof.

In another aspect, a fire extinguishing mixture is provided comprising water and an extinguishing compound that includes fluorocarbons, such as hydrofluorocarbons, fluoroethers, bromofluorocarbons, fluoroketones and/or mixtures thereof.

In another aspect, a fire extinguishing mixture is provided that comprises an extinguishing compound that includes fluorocarbons such as hydrofluorocarbons, fluoroethers, bromofluorocarbons, fluoroketones and/or mixtures thereof, and a suppressing additive that includes diluent gases, water and/or mixtures thereof.

Fluoroketones useful in accordance with the present invention include CF₃CF₂C(O)CF(CF₃)₂, (CF₃)₂CPC(O)CF(CF₃)₂, CF₃(CF₂)₂C(O)CF(CF₃)₂, CF₃(CF₂)₃C(O)CF(CF₃)₂, CF₃(CF₂)₅C(O)CF₃, CF₃CF₂C(O)CF₂CF₂F₃, CF₃C(O)CF(CF₃)₂, perfluorocyolohexanone and/or mixtures thereof.

Fluoroethers useful in accordance with the present invention include CF₃CHFCF₂OCNF₂, CF₃CHFCF₂OCF₃, (CF₃)₂CHOCHF₂, CHF₂CF₂OCF₂, CF₃CFHOCHF₂, CF₃CFHOCF₃, CF₂=(CF₃)OCF₃, CF₂=C(CF₃)OCHF₂, CF₃CF=CFOCHF₂, CF₂=CFCF₂OCHF₂, CF₃CF=CFOCF₃, CF₂=CFCF₂OCF₃ CF₃CH=CFOCHF₂, CF₃CH=CFOCF₃, CF₃CHBrCF₂OCF₃, CF₃CFBrCF₂OCHF₂, CF₃CHFCF₂OCH₂Br, CF₂BrCF₂OCH₂CF₃, CHF₂CF₂OCH₂Br and/or mixtures thereof.

Fluorocarbons useful in accordance with the present invention include trifluoromethane (CF₃H), pentafluoroethane (CF₃CF₂H), 1.1.1,2-tetraftuoroethane (CF₃CH₂F), 1,1,2,2-tetrafluoroethane (HCF₂CF₂H), 1,1,1,2,3,3,3-heptafluoropropane (CF₃CHFCF₃), 1,1,1,2,2,3,3-heptefluoroprupane (CF₃CF₂CF₂H), 1,1,1,3,3,3-hexafluoropropane (CF₃CH₂CF₃), 1,1,1,2,3,3-hexafluoropropane (CF₃CHFCF₂H), 1,1,2,2,3.3-hexafluoropropane (HCF₂CF₂CF₂H), 1,1,1,2,2,3-hexafluoropropane (CF₃CF₂CH₂F), 1,1,1,2,2-pentafluorobutane (CF₃CH₂CF₂CH₃), CF₃CBr=CH₂, CF₃CH=CHBr, CF₂BrCH=CH₂, CF₂BrCF₂CH=CH₂, CF₃CBr=CF₂ and/or mixtures thereof.

In an aspect of the present invention, methods are provided for extinguishing, suppressing and/or preventing fires using the mixtures of the present invention. in an aspect of the present invention, fire extinguishing, preventing and/or suppressing systems that deliver the mixtures of the present invention are disclosed.

In an aspect of the present invention, methods are provided for extinguishing a fire in a room comprising introducing water to the room; introducing a diluent gas into the room; and introducing an extinguishing compound.

<u style="single">BRIEF DESCRIPTION OF THE DRAWINGS</u>

The Figure shows an illustration of an application of extinguishing mixtures in accordance with an aspect of the present invention.

<u style="single">DESCRIPTION OF THE EMBODIMENTS</u>

The present invention provides fire extinguishing mixtures which comprise blends of extinguishing agents that extinguish fires through inertion, and/or dilution, as well as, chemical, and/or thermal extinguishment. The present invention also provides methods of extinguishing, preventing and/or suppressing a fire using such fire extinguishing mixtures. The present invention further provides fire extinguishing, preventing and/or suppressing systems for delivering such fire extinguishing mixtures. Exemplary aspects of the present invention are described with reference to the Figure.

Referring to the Figure, a space 17 configured with a fire extinguishing system 1 is shown. Fire extinguishing system 1 includes an extinguishing compound storage vessel 3 contiguous with an extinguishing compound dispersing nozzle 7. As depicted, a combustion 11 (as illustrated, including a fire having flames) occurs within a pan 13 on a pedestal 15. An extinguishing mixture 9 exists within space 17 and is applied to substantially extinguish combustion 11.

While depicted in two dimensions, space 17, for purposes of this disclosure, should be considered to have a volume determined from its dimensions (e.g., width, height and length). While the Figure illustrates a system configured for extinguishing fires within a space that as illustrated appears to be enclosed, the application of the mixtures, systems and methods of the present invention are not so limited. In some aspects, the present invention may be used to extinguish fires in open spaces as well as confined spaces.

All combustion suitable for extinguishment, suppression or prevention using the mixtures of the present invention or utilizing the methods and systems according to the present invention, are at least partially surrounded by a space. The available volume of this space can be filled with the compositions of the present invention to extinguish, suppress and/or prevent combustion. Typically the available volume is that volume which can be occupied by a liquid or a gas (i.e. that volume within which fluids (gases and liquids) can exchange). Solid constructions are typically not part of the available volume.

Furthermore, the Figure illustrates a single extinguishing agent storage vessel 3. It should be understood that extinguishing mixture 9 can be provided to space 17 from multiple extinguishing agent storage vessels 3 and the present invention should not be limited to mixtures that can be provided from a single vessel nor methods or systems that utilize a single vessel. Generally, combustion 11 is extinguished when extinguishing mixture 9 is introduced from vessel 3 through nozzle 9 to space 17.

In one aspect of the present invention, extinguishing mixture 9 can comprise, consist essentially of and/or consist of an extinguishing compound and a suppressing additive. In another aspect, extinguishing mixture 9 can comprise, consist essentially of and/or consist of an extinguishing compound and a diluent gas. In a further aspect, extinguishing mixture 9 can comprise, consist essentially of and/or consist of an extinguishing compound and water. In still another aspect, extinguishing mixture 9 can comprise, consist essentially of and/or consist of an extinguishing compound, a diluent gas and water.

The suppressing additive employed can include diluent gases, water and/or mixtures thereof. Exemplary diluent gases can include nitrogen, argon, helium, carbon dioxide and/or mixtures thereof. In an exemplary aspect these gases can deprive fires of necessary fuels, such as oxygen. In the same or other aspects these diluent gases resist decomposition when exposed to Combustion. In some cases these gases are referred to as inert gases. An exemplary diluent gas can comprise, consist essentially of, and/or consist of nitrogen. In one aspect, the concentration of the diluent gas is from about 5% (v/v) to about 26% (v/v). In another aspect the diluent gas may be employed at a concentration of from about 8% (v/v) to about 32% (v/v). In another aspect the diluent gas may be employed at a concentration of from about 4% (v/v) to about 13% (v/v).

It should be understood that the % (v/v) values set forth in this description and in the claims are based on space volume and refer to the design concentration as adopted and described by the <nplcit id="ncit0001" npl-type="b"><text>National Fire Protection Association in NFPA 2001, Standard on Clean Agent Fire Extinguishing, 2000 editi</text></nplcit><i>on,</i> the entirety of which is incorporated by reference herein. The equation used to calculate the concentration of the diluent gas is as follows: <maths id="math0001" num=""><math display="block"><mi mathvariant="normal">X</mi><mo mathvariant="normal">=</mo><mn mathvariant="normal">2.303</mn><mfenced separators=""><msub><mi mathvariant="normal">V</mi><mi mathvariant="normal">s</mi></msub><mo mathvariant="normal">/</mo><mi mathvariant="normal">s</mi></mfenced><mo>⁢</mo><msub><mi>log</mi><mn mathvariant="normal">10</mn></msub><mo>⁢</mo><mfenced separators=""><mn mathvariant="normal">100</mn><mo mathvariant="normal">/</mo><mn mathvariant="normal">100</mn><mo mathvariant="normal">-</mo><mi mathvariant="normal">C</mi></mfenced></math><img file="EP1925338A1_D0001.tif" /></maths> where: <ul id="ul0001" list-style="none"><li>X= volume of diluent gas added (at standard conditions of 1.013bar, 21°C), per volume of hazard space, (m³)</li><li>V_s= specific volume of diluent gas agent at 21 °C and 1.013 bar.</li><li>s= specific volume of diluent gas at 1 atmosphere and temperature, t (m³/kg)</li><li>t= minimum anticipated temperature of the protected volume (°C)</li><li>C= diluent gas design concentration (%)</li></ul>

In another aspect of the present invention, the suppressing additive includes water. Water may be stored and delivered by any standard water storage and delivery system. In one aspect, the water is delivered at a pressure from about 34 kPa to about 690 kPa and, in another aspect it is delivered at a pressure from about 69 kPa to about 827 kPa. In one aspect, the water is delivered at a flow rate of from about 0.03532 L\min\m³ to about 1.06 L\min\m³ and, in another aspect, from about 0.1766 L\min\m³to about 0.71 L\min\m³.

Water may exist in the fire extinguishing mixture in the form of droplets, fog, steam, gas and/or mixtures thereof. In the case of droplets, the majority of water particles can be about 100 µm or less in diameter, and/or from about 20 µm to about 30 µm.

In the case of fog, the majority of water particles can be from about 1 µm to about 10 µm in diameter. The fog may be produced and delivered using any technique and/or system known in the art such as dual injections nozzle system. Fog might also be produced using a higher pressure nozzle system.

In the case of steam, the water may have particle sizes of less than 1 µm and may be produced and delivered using any known technique or system for vaporizing water.

The extinguishing compound can include fluorocarbons such as fluoroketones, fluoroethers and/or mixtures thereof.

Fluoroketones useful as extinguishing compounds in accordance with the present invention can include CF₃CF₂O(O)CF(CF₃)₂, (CF₃)₂CFC(O)CF(CF₃)₂. CF₃(CF₂)₂C(O)CF(CF₃)₂, CF₃(CF₂)₃C(O)CF(CF₃)₂, CF₃(CF₂)₅C(O)CF₃, CF₃CF₂C(O)CF₂CF₂CF₃, CF₃C(O)CF(CF₃)₂, perfluorocyclohexanone and/or mixtures thereof. The extinguishing mixture can comprise from about 0.2% (v/v) to about 10% (v/v) fluoroketone, in some applications, from about 0.1 % (v/v) to about 6% (v/v) fluoroketone and, in particular applications from about 0.5% (v/v) to about 4% (v/v) fluoroketone. The fluoroketone can comprise, consist essentially of and/or consist of CF₃CF₂C(O)CF(CF₃)₂. In another aspect, the extinguishing mixture comprises from about 1.7% (v/v) to about 3.8% (v/v) CF₃CF₂C(O)CF(CF₃)₂.

The equation used to calculate the concentrations of extinguishing compounds has likewise been adopted by the National Fire Protection Association and is as follows: <maths id="math0002" num=""><math display="block"><mi mathvariant="normal">W</mi><mo mathvariant="normal">=</mo><mi mathvariant="normal">V</mi><mo mathvariant="normal">/</mo><mi mathvariant="normal">s</mi><mspace width="1em" /><mfenced separators=""><mi mathvariant="normal">C</mi><mo mathvariant="normal">/</mo><mn mathvariant="normal">100</mn><mo mathvariant="normal">-</mo><mi mathvariant="normal">C</mi></mfenced></math><img file="EP1925338A1_D0002.tif" /></maths> Where: <ul id="ul0002" list-style="none" compact="compact"><li>W = weight of extinguishing compound (kg)</li><li>V = volume of test space (m³)</li><li>s = specific volume of extinguishing compound at test temperature (m³/kg)</li><li>C = concentration (% (v/v))</li></ul>

In another aspect of the present invention, the extinguishing compound can be selected from the group of fluoroethers consisting of CF₃CHFCF₂OCHF₂, CF₃CHFCF₂OCF₃, (CF₃)₂CHOCHF₂, CHF₂CF₂OCF₂, CF₃CFHOCHF₂, CF₃CFHOCF₃, CF₂=C(CF₃)OCF₃, CF₂=C(CF₃)OCHF₂, CF₃CF=CFOCHF₂, CF₂=CFCF₂OCHF₂, CF₃CF=CFOCF₃, CF₂=CFCF₂OCF₃ CF₃CH=CFOCHF₂, CF₃CH=CFOCF₃, CF₃CHBrCF₂OCF₃, CF₃CFBrCF₂OCHF₂, CF₃CHFCF₂OCH₂Br, CF₂BrCF₂OCH₂CF₃, CHF₂CF₂OCH₂Br and/or mixtures thereof.

The extinguishing mixture can comprise from about 0.2% (v/v) to about 5.8% (v/v) fluoroether, in some applications from about 0.1% (v/v) to about 6.0% (v/v) fluoroether and, in particular applications from about 0.1% (v/v) to about 4.8% (v/v) fluoroether. The fluoroether can comprise, consist essentially of and/or consist of CF₃CHFCF₂OCHF₂. In another aspect, the extinguishing mixture can comprise from about 0.1% (v/v) to about 4.8% (v/v) CF₃CHFCF₂OCHF₂.

In another aspect of the present invention, the extinguishing mixture can include a bromofluoropropene selected from the group consisting of CF₃CBr=CH₂, CF₃CH=CHBr, CF₂BrCH=CH₂, CF₂Br₂CH=CH₂, and/or mixtures thereof. The extinguishing mixture can comprise from about 0.2% (v/v) to about 5% (v/v) bromofluoropropene, in some applications from about 0.1 % (v/v) to about 5% (v/v) bromofluoropropene and, in particular applications, from about 1% (v/v) to about 3% (v/v) bromofluoropropene. The bromofluoropropene can comprise, consist essentially of and/or consist of CF₃CBr=CH₂. In an application, the extinguishing mixture can comprise from about 0.2% (v/v) to about 4.2% (v/v) CF₃CBr=CH₂, and, in some applications from about 0.2% (v/v) to about 3.0% (v/v) CF₃CBr=CH₂.

In another aspect, the extinguishing mixture can include hydrofluorocarbons selected from the group consisting of trifluoromethane (CF₃H), pentafluoroethane (CF₃CF₂H), 1,1,1,2-tetrafluoroathane (CF₃CH₂F), 1,1,2,2-tetrafluoroethane (HCF₂CF₂H), 1,1,1,2,3,3,3-heptafluoropropane (CF₃CHFCF₃), 1,1,1,2,2,3,3-heptafluoropropane (CF₃CF₂CF₂H), 1,1,1,3,3,3-hexafluoropropane (CF₃CH₂F₃), 1,1,1,2,3,3-hexafluoropropane (CF₃CHFCF₂H), 1,1,2,2,3,3-hexafluoropropane (HCF₂CF₂CF₂H), 1,1,1,2,2,3-hexafluoropropane (CF₃CF₂CH₂F) and/or mixtures thereof. In one aspect, the extinguishing mixture can comprise from about 1% (v/v) to about 10% (v/v) hydrofluorocarbon and, in some applications, from about 3% (v/v) to about 6% (v/v) hydrofluorocarbon. The hydrofluorocarbon can comprise, consist essentially of and/or consist of heptafluoropropane. In one aspect, the extinguishing mixture can comprise from about 4% (v/v) to about 9% (v/v) heptafluoropropane.

Referring again to the Figure, systems according to the present invention provide for the storage and discharge of the extinguishing mixtures described above. In an exemplary aspect, the extinguishing compound may be stored In vessel 3 connected via appropriate piping and valves to discharge nozzle 7 located proximate space 17. Vessel 3 may be connected to the same nozzle 7 used to discharge the gas and/or water stored in the same or alternative vessel, Vessel 3 may be a conventional fire extinguishing agent storage cylinder fitted with a dip tube to afford delivery of the extinguishing compound, diluent gas and/or water through a piping system. The extinguishing compound in the cylinder may be super-pressurized in the cylinder using nitrogen or another gas, typically to levels of 360 or 600 psig. In the case of lower boiling extinguishing compounds, the extinguishing compound may be stored in and delivered from the vessel without the use of any super-pressurization.

In another aspect, an extinguishing system of the present invention can provide for storing the extinguishing compound as a pure material in vessel 3 to which can be connected a pressurization system (not shown) that may include the diluent gas and/or water. In this case, the extinguishing compound can be stored as a liquid in vessel 3 under its own equilibrium vapor pressure at ambient temperatures, and upon detection of a fire, vessel 3 may be pressurized by suitable means. Once pressurized to the desired level, the delivery of extinguishing mixture 9 can be activated. One method useful for delivering extinguishing mixture 9 to an enclosure is referred to as a "piston flow" method and is described in <patcit id="pcit0002" dnum="US8112822B"><text>Robin, et al. U.S. Pat. No. 8,112,822</text></patcit>, which is hereby incorporated by reference.

Methods according to the present invention include those methods that provide the extinguishing mixtures of the present invention. In one aspect, a method can include delivering water, diluent gas, and the extinguishing compound to a space simultaneously upon detection of the fire. In another aspect, upon detection of the fire the delivery of the water may be initiated first. Delivery of the diluent gas can be initiated at a later time, either during or after the water discharges. Delivery of the extinguishing compound can then be initiated after initiation of the delivery of the diluent gas.

In another aspect, methods according to the present invention provide for the delivery of both the water and the diluent gas simultaneously followed by the delivery of the extinguishing compound, either during or after the discharge of the diluent gas and water. In yet another aspect, the delivery of the diluent gas may be initiated prior to the initiation of the delivery of the water. Delivery of the water and extinguishing compound is then initiated either during or after the diluent gas is discharged.

The invention will be further described with reference to the following specific examples. However, it will be understood that these examples are illustrative and not restrictive in nature.

EXAMPLE I

Extinguishing concentrations of the fluoroketone CF₃CF₂C(O)CF(CF₃)₂ were determined using a cup burner apparatus, as described in <nplcit id="ncit0002" npl-type="s"><text>M. Robin and Thomas F. Rowland, "Development of a Standard Cup Burner Apparatus: NFPA and ISO Standard Methods, 1999 Halon Options Technical Working Conference, Apr. 27-29, 1999</text></nplcit>, Albuquerque, N.Mex." and Incorporated herein by reference. The cup burner method is a standard method for determining extinguishing mixtures, and has been adopted in both national and international fire suppression standards. For example NFPA 2001 Standard on Clean Agent Fire Extinguishing Systems and ISO 14520-1: Gaseous Fire-Extinguishing Systems, both utilize the cup burner method.

A mixture of air, nitrogen and CF₃CF₂C(O)CF(CF₃)₂ was flowed through an 85-mm (ID) Pyrex chimney around a 28-mm (OD) fuel cup. A wire mesh screen and a 76 mm (3 inch) layer of 3 mm (OD) glass beads were employed in the diffuser unit to provide thorough mixing of air, nitrogen and CF₃CF₂C(O)CF(CF₃)₂.

<i>n</i>-Heptane was gravity fed to a cup from a liquid fuel reservoir consisting of a 250 mL separatory funnel mounted on a laboratory jack, which allowed for an adjustable and constant liquid fuel level in the cup. The fuel was ignited with a propane mini-torch, the chimney was placed on the apparatus. The fuel level was then adjusted such that fuel was 1-2 mm from the ground inner edge of the cup. A 90 second preburn period was allowed, and a primary flow of air and nitrogen was initiated at 34.2 Umin.

Primary and secondary air flows were monitored by flow meters (240 and 225 tubes, respectively). Nitrogen flows were monitored with a flow meter (230 tube). Oxygen concentrations were calculated from the measured air and nitrogen flow rates. The flows were maintained until the flames were extinguished. The prima ry flow of 34.2 L/min was maintained in all the tests. The secondary flow of ai r was passed through CF₃CF₂C(O)CF(CF₃)₂ contained in a 1150 ml steel mixing chamber equipped with a dip-tube. The secondary flow, containing air saturated with CF₃CF₂C(O)CF(CF₃)₂, exited the mixing chamber and was mixed with the primary air flow before entering the cup burner's diffuser unit.

Immediately following flame extinction, a sample of the gas stream at a point near the lip of the cup was collected through a length of plastic tubing attached to a Hamilton three way valve and multifit gas syringe. The sample was then subjected to gas chromatographic analysis (G.C.). G.C. calibration was performed by preparing standards samples in a 1L Tedlar bag. A summary of test parameters and results are shown below in Table 1. <tables id="tabl0001" num="0001"><table frame="all"><title>TABLE 1</title><tgroup cols="5"><colspec colnum="1" colname="col1" colwidth="64mm" /><colspec colnum="2" colname="col2" colwidth="19mm" /><colspec colnum="3" colname="col3" colwidth="19mm" /><colspec colnum="4" colname="col4" colwidth="19mm" /><colspec colnum="5" colname="col5" colwidth="47mm" /><thead><row><entry namest="col1" nameend="col5" align="center" valign="top">Extinguishment of <i>n</i>-heptane Flames with CF₃CF₂C(O)CF(CF₃)₂</entry></row><row><entry align="center" valign="top">Total Air Flow [Primary + Secondary] (L/min)</entry><entry align="center" valign="top">N₂(L/min)</entry><entry align="center" valign="top">N₂ % (v/v)</entry><entry align="center" valign="top">O₂ % (v/v)</entry><entry align="center" valign="top">CF₃CF₂C(O)CF(CF₃)₂ % (v/v)</entry></row></thead><tbody><row><entry align="char" char=".">38.7</entry><entry align="char" char="." charoff="20">0.0</entry><entry align="char" char="." charoff="20">0.0</entry><entry align="char" char="." charoff="20">20.6</entry><entry align="center">4.1</entry></row><row><entry align="char" char=".">39.0</entry><entry align="char" char="." charoff="20">2.1</entry><entry align="char" char="." charoff="20">5.2</entry><entry align="char" char="." charoff="20">19.5</entry><entry align="center">3.8</entry></row><row><entry align="char" char=".">37.7</entry><entry align="char" char="." charoff="20">3.3</entry><entry align="char" char="." charoff="20">8.0</entry><entry align="char" char="." charoff="20">18.9</entry><entry align="center">3.4</entry></row><row><entry align="char" char=".">37.7</entry><entry align="char" char="." charoff="20">4.5</entry><entry align="char" char="." charoff="20">10.6</entry><entry align="char" char="." charoff="20">18.4</entry><entry align="center">3.1</entry></row><row><entry align="char" char=".">36.8</entry><entry align="char" char="." charoff="20">5.7</entry><entry align="char" char="." charoff="20">13.5</entry><entry align="char" char="." charoff="20">17.8</entry><entry align="center">2.8</entry></row><row><entry align="char" char=".">36.3</entry><entry align="char" char="." charoff="20">7.0</entry><entry align="char" char="." charoff="20">16.2</entry><entry align="char" char="." charoff="20">17.3</entry><entry align="center">2.4</entry></row><row><entry align="char" char=".">36.3</entry><entry align="char" char="." charoff="20">8.3</entry><entry align="char" char="." charoff="20">18.6</entry><entry align="char" char="." charoff="20">16.8</entry><entry align="center">2.1</entry></row><row><entry align="char" char=".">35.9</entry><entry align="char" char="." charoff="20">9.6</entry><entry align="char" char="." charoff="20">21.1</entry><entry align="char" char="." charoff="20">16.3</entry><entry align="center">1.8</entry></row><row><entry align="char" char=".">35.8</entry><entry align="char" char="." charoff="20">10.9</entry><entry align="char" char="." charoff="20">23.4</entry><entry align="char" char="." charoff="20">15.8</entry><entry align="center">1.5</entry></row><row><entry align="char" char=".">35.4</entry><entry align="char" char="." charoff="20">12.2</entry><entry align="char" char="." charoff="20">25.6</entry><entry align="char" char="." charoff="20">15.3</entry><entry align="center">1.2</entry></row><row><entry align="char" char=".">34.2</entry><entry align="char" char="." charoff="20">15.4</entry><entry align="char" char="." charoff="20">30.6</entry><entry align="char" char="." charoff="20">14.3</entry><entry align="center">0</entry></row></tbody></tgroup></table></tables>

EXAMPLE II

Example I was repeated, substituting, in once instance the bromofluoropropene CF₃CBr=CH₂, alone (under ambient oxygen conditions) for CF₃CF₂C(O)CF(CF₃)₂, and, in another instance, CF₃CBr=CH₂ in combination with diluent gas (reduced oxygen conditions) for CF₃CF₂C(O)CF(CF₃)₂. A summary of test parameters and results are shown below in Tables 2 and 3 respectively. <tables id="tabl0002" num="0002"><table frame="all"><title>TABLE 2</title><tgroup cols="2"><colspec colnum="1" colname="col1" colwidth="37mm" /><colspec colnum="2" colname="col2" colwidth="45mm" /><thead><row><entry namest="col1" nameend="col2" align="center" valign="top">Extinguishment of <i>n</i>-heptane Flames with CF₃CBr=CH₂</entry></row><row><entry align="center" valign="top">Total Flow (L/min.)</entry><entry align="center" valign="top">CF₃CBr=CH₂ % (v/v)</entry></row></thead><tbody><row><entry align="center">35.42</entry><entry align="center">3.7</entry></row><row><entry align="center">42.66</entry><entry align="center">3.7</entry></row><row><entry align="center">42.32</entry><entry align="center">3.5</entry></row><row><entry align="center">42.54</entry><entry align="center">3.6</entry></row><row><entry align="center">42.54</entry><entry align="center">3.9</entry></row><row><entry align="center">42.54</entry><entry align="center">3.6</entry></row><row><entry align="center" /><entry align="center" /></row><row><entry align="center" /><entry align="center">Avg.=3.7</entry></row><row><entry align="center" /><entry align="center">STDEV=0.2</entry></row><row><entry align="center" /><entry align="center">High = 3.9</entry></row><row><entry align="center" /><entry align="center">Low = 3.5</entry></row></tbody></tgroup></table></tables><tables id="tabl0003" num="0003"><table frame="all"><title>TABLE 3</title><tgroup cols="5"><colspec colnum="1" colname="col1" colwidth="31mm" /><colspec colnum="2" colname="col2" colwidth="18mm" /><colspec colnum="3" colname="col3" colwidth="18mm" /><colspec colnum="4" colname="col4" colwidth="20mm" /><colspec colnum="5" colname="col5" colwidth="35mm" /><thead><row><entry namest="col1" nameend="col5" align="center" valign="top">Extinguishment of <i>n</i>-heptane flames with CF₃CBr=CH₂ and N₂*</entry></row><row><entry align="center" valign="top">Total Flow (L/min)</entry><entry align="center" valign="top">N₂(L/min)</entry><entry align="center" valign="top">N₂ % (v/v)</entry><entry align="center" valign="top">O₂ % (v/v)</entry><entry align="center" valign="top">CF₃CBr=CH₂ % (v/v)</entry></row></thead><tbody><row><entry align="char" char="." charoff="12">35.4</entry><entry align="center">0</entry><entry align="char" char="." charoff="20">0.0</entry><entry align="char" char="." charoff="19">20.6</entry><entry align="char" char="." charoff="6">3.7</entry></row><row><entry align="char" char="." charoff="12">35.7</entry><entry align="center">2.1</entry><entry align="char" char="." charoff="20">5.7</entry><entry align="char" char="." charoff="19">19.4</entry><entry align="char" char="." charoff="6">3.0</entry></row><row><entry align="char" char="." charoff="12">38.5</entry><entry align="center">3.5</entry><entry align="char" char="." charoff="20">9.2</entry><entry align="char" char="." charoff="19">18.7</entry><entry align="char" char="." charoff="6">1.9</entry></row><row><entry align="char" char="." charoff="12">40.8</entry><entry align="center">6.0</entry><entry align="char" char="." charoff="20">14.7</entry><entry align="char" char="." charoff="19">17.6</entry><entry align="char" char="." charoff="6">1.4</entry></row><row><entry align="char" char="." charoff="12">41.6</entry><entry align="center">7.0</entry><entry align="char" char="." charoff="20">16.9</entry><entry align="char" char="." charoff="19">17.1</entry><entry align="char" char="." charoff="6">1.0</entry></row><row><entry align="char" char="." charoff="12">44.9</entry><entry align="center">10.6</entry><entry align="char" char="." charoff="20">23.6</entry><entry align="char" char="." charoff="19">15.7</entry><entry align="char" char="." charoff="6">0.4</entry></row><row><entry align="char" char="." charoff="12">46.5</entry><entry align="center">12.2</entry><entry align="char" char="." charoff="20">26.2</entry><entry align="char" char="." charoff="19">15.2</entry><entry align="char" char="." charoff="6">0.2</entry></row><row><entry align="char" char="." charoff="12">49.0</entry><entry align="center">14.8</entry><entry align="char" char="." charoff="20">30.2</entry><entry align="char" char="." charoff="19">14.4</entry><entry align="char" char="." charoff="6">0.0</entry></row></tbody></tgroup><tgroup cols="5" rowsep="0"><colspec colnum="1" colname="col1" colwidth="31mm" /><colspec colnum="2" colname="col2" colwidth="18mm" /><colspec colnum="3" colname="col3" colwidth="18mm" /><colspec colnum="4" colname="col4" colwidth="20mm" /><colspec colnum="5" colname="col5" colwidth="35mm" /><tbody><row><entry namest="col1" nameend="col5" align="justify">*Primary air flow 34.2 L/min.</entry></row></tbody></tgroup></table></tables>

As indicated in Table 2, under ambient oxygen conditions the concentration of CF₃CBr=CH₂ required to extinguish <i>n</i>-heptane flames averages 3.7% (v/v). Table 3 demonstrates that when used in combination with nitrogen, CF₃CBr=CH₂ extinguishes the <i>n</i>-heptane flames at a much lower concentration, as low as about 0.41% (v/v), while maintaining human-safe oxygen levels.

EXAMPLE III

Example I was repeated, substituting the fluoroether CF₃CHFCF₂OCHF₂ for CF₃CF₂C(O)CF(CF₃)₂. A summary of the test parameters and results are shown below in Table 4. <tables id="tabl0004" num="0004"><table frame="all"><title>TABLE 4</title><tgroup cols="5"><colspec colnum="1" colname="col1" colwidth="31mm" /><colspec colnum="2" colname="col2" colwidth="27mm" /><colspec colnum="3" colname="col3" colwidth="20mm" /><colspec colnum="4" colname="col4" colwidth="20mm" /><colspec colnum="5" colname="col5" colwidth="43mm" /><thead><row><entry namest="col1" nameend="col5" align="center" valign="top">Extinguishment of <i>n</i>-heptane Flames with CF₃CHFCF₂OCHF₂ and N₂</entry></row><row><entry align="center" valign="top">Total Flow (L/min.)</entry><entry align="center" valign="top">N₂ Flow (L/min)</entry><entry align="center" valign="top">N₂ % (v/v)</entry><entry align="center" valign="top">O₂ % (v/v)</entry><entry align="center" valign="top">CF₃CHFCF₂OCHF₂ % (v/v)</entry></row></thead><tbody><row><entry align="char" char="." charoff="12">31.7</entry><entry align="center">0</entry><entry align="center">0</entry><entry align="char" char="." charoff="19">20.6</entry><entry align="char" char="." charoff="5">5.7</entry></row><row><entry align="char" char="." charoff="12">31.2</entry><entry align="center">2.89</entry><entry align="center">8.5</entry><entry align="char" char="." charoff="19">19.9</entry><entry align="char" char="." charoff="5">4.8</entry></row><row><entry align="char" char="." charoff="12">31.0</entry><entry align="center">4.16</entry><entry align="center">11.8</entry><entry align="char" char="." charoff="19">18.2</entry><entry align="char" char="." charoff="5">4.3</entry></row><row><entry align="char" char="." charoff="12">29.9</entry><entry align="center">6.00</entry><entry align="center">16.7</entry><entry align="char" char="." charoff="19">17.2</entry><entry align="char" char="." charoff="5">3.3</entry></row><row><entry align="char" char="." charoff="12">29.6</entry><entry align="center">7.34</entry><entry align="center">19.9</entry><entry align="char" char="." charoff="19">16.5</entry><entry align="char" char="." charoff="5">2.8</entry></row><row><entry align="char" char="." charoff="12">28.6</entry><entry align="center">8.71</entry><entry align="center">23.4</entry><entry align="char" char="." charoff="19">15.8</entry><entry align="char" char="." charoff="5">1.8</entry></row><row><entry align="char" char="." charoff="12">27.8</entry><entry align="center">10.80</entry><entry align="center">28.0</entry><entry align="char" char="." charoff="19">14.8</entry><entry align="char" char="." charoff="5">0.9</entry></row><row><entry align="char" char="." charoff="12">27.3</entry><entry align="center">12.80</entry><entry align="center">31.9</entry><entry align="char" char="." charoff="19">14.0</entry><entry align="char" char="." charoff="5">0.0</entry></row></tbody></tgroup></table></tables>

EXAMPLE IV

Example I was repeated, substituting the hydrofluorocarbon CF₃CH₂F for CF₃CF₂C(O)CF(CF₃)₂. A summary of the test parameters and results are shown below in Table 5. <tables id="tabl0005" num="0005"><table frame="all"><title><b>TABLE 5</b></title><tgroup cols="5"><colspec colnum="1" colname="col1" colwidth="31mm" /><colspec colnum="2" colname="col2" colwidth="27mm" /><colspec colnum="3" colname="col3" colwidth="20mm" /><colspec colnum="4" colname="col4" colwidth="20mm" /><colspec colnum="5" colname="col5" colwidth="29mm" /><thead><row><entry namest="col1" nameend="col5" align="center" valign="top">Extinguishment of <i>n</i>-heptane Flames with CF₃CH₂F and N₂</entry></row><row><entry align="center" valign="top">Total Flow (L/min.)</entry><entry align="center" valign="top">N₂ Flow (Umin)</entry><entry align="center" valign="top">N₂ % (v/v)</entry><entry align="center" valign="top">O₂ % (v/v)</entry><entry align="center" valign="top">CF₃CH₂F % (v/v)</entry></row></thead><tbody><row><entry align="center">41.1</entry><entry align="center">0</entry><entry align="center">0</entry><entry align="char" char="." charoff="19">20.6</entry><entry align="center">9.6</entry></row><row><entry align="center">41.1</entry><entry align="center">3.29</entry><entry align="center">7.4</entry><entry align="char" char="." charoff="19">19.1</entry><entry align="center">7.9</entry></row><row><entry align="center">41.1</entry><entry align="center">6.58</entry><entry align="center">13.8</entry><entry align="char" char="." charoff="19">17.8</entry><entry align="center">6.2</entry></row><row><entry align="center">41.1</entry><entry align="center">9.66</entry><entry align="center">19</entry><entry align="char" char="." charoff="19">16.7</entry><entry align="center">4.5</entry></row><row><entry align="center">41.1</entry><entry align="center">12.2</entry><entry align="center">22.9</entry><entry align="char" char="." charoff="19">15.9</entry><entry align="center">3.3</entry></row><row><entry align="center">41.1</entry><entry align="center">14.8</entry><entry align="center">26.9</entry><entry align="char" char="." charoff="19">15.1</entry><entry align="center">1.6</entry></row><row><entry align="center">41.1</entry><entry align="center">18.4</entry><entry align="center">30.9</entry><entry align="char" char="." charoff="19">14.2</entry><entry align="center">0</entry></row></tbody></tgroup></table></tables>

EXAMPLE V

<i>n</i>-Heptane fires where extinguished utilizing an extinguishing mixture according to the present invention. The fire extinguishing tests were conducted according to the test protocol described in UL-2166. More specifically, Class B fire extinguishing tests were conducted using a 0.23 m² square test pan located in the center of a room. The test pan contained at least 5.08 cm of <i>n</i>- heptane with at least 5.08 cm of free board from the top of the pan. The pan was made of steel having a thickness of 0.635 cm and liquid tight welded joints. The pan also included a 3.81 cm (1 ½") (3/16" thickness) angle to reinforce the upper edge.

The internal dimensions of the test facility (room) were 8m x 4m x 3.6m (height); precise measurement of the test portion of the facility yielded a total volume of 115m³. The enclosure walls were constructed of standard concrete cinder block, filled with insulation and covered on the interior with 1,59 cm plywood. The ceiling and floor both consisted of two layers of 1.91 cm plywood on wooden 5.08 cm x 15.24 cm joists, with alternate layers of plywood staggered so that no joints overlapped. The ceiling was also covered with 1.59 cm gypsum wallboard, and the walls and ceiling were finished with tape and joint compound and painted with two coats of primer (Kilz). The windows consisted of standard units employing safety glass and were covered on the interior with Lexan sheets. The enclosure door was of standard solid core construction.

A 45-72 cm x 45.72 cm hinged positive pressure vent installed in a recess in the ceiling was kept open during testing. The ventilation inlet to the enclosure, through an underfloor duct, remained closed during this evaluation. A 3.5 ton commercial heat pump unit provided temperature control of the room. The inlet and outlet ducts were equipped with closable shutters. The exhaust system was also fitted with a closable shutter.

Water spray was discharged at 45 seconds from ignition and continued until extinguishment. The water spray flow rate is shown in Table 5. Water spray was provided using 6 "90 degree solid cone nozzles". These nozzles were installed approximately 150 cm from the ceiling and were installed to cover the whole area of the floor. In some part of the space, there was an overlap of the spray. Heptafluoropropane was discharged 60 seconds from the beginning of water spray discharge (105 seconds from ignition). Each test was conducted at least three times and the parameters and results are summarized in Table 6. <tables id="tabl0006" num="0006"><table frame="all"><title>TABLE 6</title><tgroup cols="5"><colspec colnum="1" colname="col1" colwidth="13mm" /><colspec colnum="2" colname="col2" colwidth="44mm" /><colspec colnum="3" colname="col3" colwidth="39mm" /><colspec colnum="4" colname="col4" colwidth="24mm" /><colspec colnum="5" colname="col5" colwidth="47mm" /><thead><row><entry namest="col1" nameend="col5" align="center" valign="top">Extinguishment of <i>n</i>-heptane Flames with Water and Heptafluoropropane</entry></row><row><entry align="center" valign="top">Test #</entry><entry align="center" valign="top">Heptafluoropropane % (v/v)</entry><entry align="center" valign="top">Heptafluoropropane (kg)</entry><entry align="center" valign="top">Water (L/min)</entry><entry align="center" valign="top">Average Extinguishment Time (sec.)</entry></row></thead><tbody><row><entry align="center">1</entry><entry align="char" char="." charoff="5">8.7</entry><entry align="char" char="." charoff="10">79.83</entry><entry align="char" char="." charoff="15">42.03</entry><entry align="char" char=".">1.0</entry></row><row><entry align="center">2</entry><entry align="char" char="." charoff="5">7.0</entry><entry align="char" char="." charoff="10">63.05</entry><entry align="char" char="." charoff="15">19.69</entry><entry align="char" char=".">6.4</entry></row><row><entry align="center">3</entry><entry align="char" char="." charoff="5">5.8</entry><entry align="char" char="." charoff="10">51.71</entry><entry align="char" char="." charoff="15">42.03</entry><entry align="char" char=".">12.6</entry></row><row><entry align="center">4</entry><entry align="char" char="." charoff="5">5.0</entry><entry align="char" char="." charoff="10">44.09</entry><entry align="char" char="." charoff="15">42.03</entry><entry align="char" char=".">16.0</entry></row><row><entry align="center">5</entry><entry align="char" char="." charoff="5">4.5</entry><entry align="char" char="." charoff="10">39.46</entry><entry align="char" char="." charoff="15">42.03</entry><entry align="char" char=".">24.53</entry></row></tbody></tgroup></table></tables>

EXAMPLE VI

Extinguishment testing was performed as described in Example IV above with the exception that the extinguishing mixture included nitrogen. Nitrogen was discharged from cylinders, pressurized to 13.79 mPa, corresponding to 5.18 m³ of nitrogen at 1 atmosphere and 21.1°C. The cylinders were connected to an end draw manifold via 1.59 cm high pressure flex hoses and cylinder actuation was accomplished via a remote manual lever release actuator. A 3.18 cm orifice union with an orifice plate connected the manifold to the remaining pipe network. This system was designed to afford a 60 second discharge of nitrogen at a concentration of 30% (v/v), and employed a centrally located 2.54 cm (1°), 360° Ansul® (Marinette, Wisconsin, USA) nozzle with an orifice of 1.43 cm². The same nitrogen piping system was employed for all tests and hence discharge times varied with the amount of nitrogen employed.

Water and nitrogen were discharged into the test enclosure 30 seconds after <i>n-</i>heptane ignition, and continued to discharge until flame extinguishment. The water spray was discharged at the rate of 62.47 L/min. At 50 seconds from the beginning of the nitrogen discharge (i.e., 80 seconds from <i>n</i>-heptane ignition), heptafluoropropane was discharged through a separate pipe system terminating in a 5.08 cm (2") 180° Chubb nozzle. Each test was conducted at least three times and the parameters and results are summarized below in Table 7. <tables id="tabl0007" num="0007"><table frame="all"><title>TABLE 7</title><tgroup cols="5"><colspec colnum="1" colname="col1" colwidth="13mm" /><colspec colnum="2" colname="col2" colwidth="42mm" /><colspec colnum="3" colname="col3" colwidth="39mm" /><colspec colnum="4" colname="col4" colwidth="19mm" /><colspec colnum="5" colname="col5" colwidth="54mm" /><thead><row><entry namest="col1" nameend="col5" align="center" valign="top">Extinguishment of <i>n</i>-heptane Flames with Water/Nitrogen/Heptafluoropropane</entry></row><row><entry align="center" valign="top">Test #</entry><entry align="center" valign="top">Heptafluoropropane %(v/v)</entry><entry align="center" valign="top">Heptafluoropropane (kg)</entry><entry align="center" valign="top">N₂ %(v/v)</entry><entry align="center" valign="top">Average Extinguishment Time (sec.)</entry></row></thead><tbody><row><entry align="center">1</entry><entry align="char" char="." charoff="5">4.3</entry><entry align="char" char="." charoff="10">37.65</entry><entry align="char" char="." charoff="20">4.4</entry><entry align="char" char=".">17.4</entry></row><row><entry align="center">2</entry><entry align="char" char="." charoff="5">4.3</entry><entry align="char" char="." charoff="10">37.65</entry><entry align="char" char="." charoff="20">8.6</entry><entry align="char" char=".">22.2</entry></row><row><entry align="center">3</entry><entry align="char" char="." charoff="5">3.5</entry><entry align="char" char="." charoff="10">30.39</entry><entry align="char" char="." charoff="20">8.6</entry><entry align="char" char=".">36.6</entry></row><row><entry align="center">4</entry><entry align="char" char="." charoff="5">3.5</entry><entry align="char" char="." charoff="10">30.39</entry><entry align="char" char="." charoff="20">12.6</entry><entry align="char" char=".">18.7</entry></row></tbody></tgroup></table></tables>

EXAMPLE VII

The test in Example V was repeated using <i>n</i>-Heptane alternative fuels, namely PMMA (polymethyl methacrylate), PP (polypropylene), ABS (acrylonitrile-butadiene-styrene polymer) or wood and permitting a longer preburn. Water spray and nitrogen were discharged into the test enclosure at 210 seconds after ignition (360 seconds in the case of wood), and continued to discharge until flame extinguishment. Heptafluoropropane was discharged at 260 seconds (420 seconds in the case of wood) from ignition and continued for between 8 and 10 seconds. A summary of the parameters and results are shown below in Table 8. <tables id="tabl0008" num="0008"><table frame="all"><title><b>TABLE 8</b></title><tgroup cols="5"><colspec colnum="1" colname="col1" colwidth="18mm" /><colspec colnum="2" colname="col2" colwidth="43mm" /><colspec colnum="3" colname="col3" colwidth="39mm" /><colspec colnum="4" colname="col4" colwidth="19mm" /><colspec colnum="5" colname="col5" colwidth="43mm" /><thead><row><entry namest="col1" nameend="col5" align="center" valign="top">Extinguishment of Alternative Fuel Flames with Water/Nitrogen/Heptafluoropropane</entry></row><row><entry align="center" valign="top">Fuel Type</entry><entry align="center" valign="top">Heptafluoropropane% (v/v)</entry><entry align="center" valign="top">Heptafluoropropane (kg)</entry><entry align="center" valign="top">N₂ %(v/v)</entry><entry align="center" valign="top">Extinguishment Time (sec)</entry></row></thead><tbody><row><entry align="center">PMMA</entry><entry align="char" char="." charoff="5">3.5</entry><entry align="char" char="." charoff="10">30.39</entry><entry align="char" char="." charoff="20">12.6</entry><entry align="center">12</entry></row><row><entry align="center">PMMA</entry><entry align="char" char="." charoff="5">3.5</entry><entry align="char" char="." charoff="10">30.39</entry><entry align="char" char="." charoff="20">12.6</entry><entry align="center">27</entry></row><row><entry align="center">PP</entry><entry align="char" char="." charoff="5">3.5</entry><entry align="char" char="." charoff="10">30.39</entry><entry align="char" char="." charoff="20">12.6</entry><entry align="center">64</entry></row><row><entry align="center">ABS</entry><entry align="char" char="." charoff="5">3.5</entry><entry align="char" char="." charoff="10">30.39</entry><entry align="char" char="." charoff="20">12.6</entry><entry align="center">88</entry></row><row><entry align="center">Wood</entry><entry align="char" char="." charoff="5">3.5</entry><entry align="char" char="." charoff="10">30.39</entry><entry align="char" char="." charoff="20">12.6</entry><entry align="center">&lt;1</entry></row></tbody></tgroup></table></tables>