JP2580075B2 - Fire extinguishing method using hydrofluorocarbon and blend for fire extinguishing - Google Patents

Abstract

Highly fluorinated, saturated, C2 and C3 hydrofluorocarbons are efficient, economical, non-ozone-depleting fire extinguishing agents used alone or in blends with other fire extinguishing agents in total flooding and portable systems.

Description

DETAILED DESCRIPTION OF THE INVENTION Cross Reference This application is a continuation-in-part of applicant's co-pending U.S. Patent Application No. 396,841 filed August 21, 1989.

FIELD OF THE INVENTION The present invention relates to fire extinguishing methods and extinguishing blends using highly fluorinated C ₂ and C ₃ saturated hydrofluorocarbon.

2. Description of the Prior Art It is generally known to use certain bromine, chlorine and iodine containing halogenated chemical agents for fire fighting. These agents are believed to be effective by interfering with the normal chain reaction that causes flame propagation. The most widely accepted flame suppression mechanism is described by Fryburg in the literature on fire extinguishers and the basic mechanisms of their action.
Review of Literature Pertinent to Fire Extingui
shing Agents and to Basic Mechanisms Involved in T
heir Action) ", a radical trapping mechanism proposed in NACA-TN 2102 (1950). Malcolm (Ma
lcom) " Vaporing Fire Extinguishing
Agents) ", Report 117, Dept. of
Army Engineering Research and Development Laboratories (Dept. of Army Engin
eering Research and Development Laboratolies, Fort Bevoir, VA, 1950 (Project-8-76-04-003), the effectiveness of halogens on a molar scale in the order Cl <Br <I. Some studies support the radical trapping mechanism. Thus, compounds containing halogens Cl, Br and I act by interfering with free radicals or ionic species in a fire, and the effectiveness of these halogens is I> Br
It is generally accepted that the order is> Cl.

In contrast, hydrofluorocarbons (ie,
Compounds containing only C, H, and F atoms) have not been found to have any chemical action to suppress combustion. Thus, to be effective as a fire extinguishing agent, the compound must be C
It is generally believed that l, Br or I must be included. The use of iodine-containing compounds as fire extinguishing agents has hitherto been avoided, mainly because of their production costs or due to toxicity considerations. All three fire extinguishing agents commonly used today are all bromine containing compounds, Halon 1301 (CF ₃ Br), Halon 1211 (CF ₂ BrCl) and Halon 2402 (CF ₂ BrCF ₂ Br). The effectiveness of these three volatile bromine containing compounds in extinguishing fires is described in Owens U.S. Pat. No. 4,014,799.
Although not used commercially, certain chlorine-containing compounds may also be useful, such as Halon 251 (CF ₃ CF ₃ Cl), as described by Larsen in US Pat. No. 3,844,354. It is known to be a fire extinguisher.

Although the bromine-containing halons listed above are effective fire extinguishing agents, some have claimed that such agents, including bromine or chlorine, can destroy the protective ozone layer of the earth. Because these agents do not contain hydrogen atoms that allow their destruction in the troposphere, the greenhouse effect (greenh
ouse warming effect).

Therefore, it is an object of the present invention to provide a fire extinguishing method that extinguishes fire quickly and effectively as well as the method using a halon agent currently used, while avoiding the above-mentioned disadvantages.

It is another object of the present invention to provide an agent for use in a process of the above nature that is effective, economically manufactured, and environmentally safe with respect to ozone depletion and greenhouse effects. .

It is yet another object of the present invention to provide a blend of hydrofluorocarbons and other fire extinguishants that is effective and environmentally safe.

SUMMARY OF THE INVENTION The above and other objects, advantages and features of the present invention are realized by using saturated highly fluorinated hydrofluorocarbons and their blends with other fire extinguishing agents as fire extinguishing agents for use in fire extinguishing methods and apparatus. . More particularly, the method of the present invention includes saturated C ₂ or C ₃ highly fluorinated hydrofluorocarbon fire extinguishing concentration is introduced into the fire, to maintain such concentration to the fire goes out. The saturated highly fluorinated hydrofluorocarbon of the present invention has the formula: C _x H _y F _z [x is 2 or 3, y is 1 or 2, and z is 5, 6
Or 7; when x is 2, y is 1 and z is 5; when x is 3, z is 6 or 7]. A particular hydrofluorocarbon useful according to the invention is heptafluoropropane (CF ₃ CHF
CF ₃ ), 1,1,1,3,3,3-hexafluoropropane (CF ₃ CH ₂
CF ₃ ), 1,1,1,2,3,3-hexafluoropropane (CF ₃ CHF
CHF ₂ ) and pentafluoroethane (CF ₃ CHF ₂ ).
These hydrofluorocarbons may be used alone, in combination with each other, or in combination with other fire extinguishing agents. Generally, the agents of the present invention comprise about 3-15% on a v / v basis,
Preferably, it is used at a concentration in the range of 5 to 10%.

According to the description of the Preferred Embodiments The present invention, saturated higher fluorinated C ₂ or C ₃ hydrofluorocarbons was found to be an effective fire extinguishing agent at a safe concentration for use. However, since such hydrofluorocarbons do not contain bromine or chlorine, their ozone depleting power is zero. Further, since the compound contains a hydrogen atom, it is easily decomposed under a low pressure, and thus has no threat as a greenhouse effect.

Certain hydrofluorocarbons useful according to the invention have the formula: C _x H _y F _z [x is 2 or 3 and y is 1 or 2
And z is 5, 6 or 7; when x is 2, y is 1 and z is 5; when x is 3, z is 6
Or 7]. Useful in accordance with the present invention, certain hydrofluorocarbons heptafluoropropane (CF ₃ CHFCF _3), 1,1,1,3,3,3- hexafluoropropane _{(CF 3 CH 2 CF 3)} , 1,1,1 , 2,3,3-hexafluoropropane (CF ₃ CHFCHF ₂ ) and pentafluoroethane (CF ₃ CHF ₂ ).

These hydrofluorocarbons may be used alone, in combination with each other, or in combination with other fire extinguishing agents. Other agents that can be blended with the hydrofluorocarbons of the present invention include, for example, halogen 1301 (CF ₃ B
r), Halon 1211 (CF ₂ BrCl), Halon 2402 (CF ₂ BrCF ₂ B
r), chlorine and / or bromine containing compounds such as Halon 251 (CF ₃ CF ₂ Cl) and CF ₃ CHFBr. Mixtures of heptafluoropropane and Halon 1201 (CF ₂ HBr) have been found to have similar vapor pressures over a wide range of temperatures, and the composition of the mixture remains relatively constant during release or other use. Are particularly preferred.

When the hydrofluorocarbons of the present invention are used in a blend, they are preferably present at a level of at least about 10% by weight, based on the weight of the blend. It is preferred to use high levels of hydrofluorocarbons in such blends to minimize the adverse environmental effects of agents containing chlorine or bromine.

The hydrofluorocarbons used according to the present invention are non-toxic and are produced economically. For example, heptafluoropropane is conveniently prepared by the reaction of commercially available hexafluoropropene (CF ₃ CF = CF ₂ ) with anhydrous HF, as described in GB 902,590. . Similarly, 1,1,1,3,3,3-hexafluoropropane is anhydrous HF and pentafluoropropane (CF ₃ CH = CF ₂ )
It is synthesized by the reaction with 1,1,1,2,3,3-hexafluoropropane is hexafluoropropane (CF ₃ CF = C
Obtained by hydrogenation of F ₂ ). Pentafluoroethane is obtained by adding hydrofluoric acid to tetrafluoroethylene (CF ₂ = CF ₂ ).

Saturated higher fluorinated C ₂ or C ₃ hydrofluorocarbons of the present invention is effectively used in substantially the lowest concentration that allows extinguishing, exact minimum level certain combustibles, the particular hydrofluorocarbon and the combustion conditions Dependent.
However, in general, best results are obtained when the hydrofluorocarbons or mixtures and blends thereof are used at an agent level of at least about 3% (v / v). Best results are obtained with an agent level of at least about 5% (v / v) when the hydrofluorocarbon is used alone. Similarly, the maximum dose is governed by economic considerations and possible toxicity to the organism. For example, in an area where people usually exist (occupied area) such as an office,
About 15% (V / V) is the maximum concentration at which the hydrofluorocarbon, mixtures and blends thereof can be conveniently used. In unoccupied areas, such as computer equipment rooms, which can be used at concentrations higher than 15% (V / V), the exact concentration depends on the particular combustible, the selected hydrofluorocarbon (or And its combustion conditions. Where "% (V /
V) "represents the volume percentage of fire extinguisher relative to the total volume of air and fire extinguishing agent. Preferred concentrations of the hydrofluorocarbon agents, mixtures and blends according to the invention are from about 5 to 10
% (V / v).

The hydrofluorocarbon can be supplied using conventional feeding methods and the methods used for halon such as, for example, Halon 1301 and Halon 1211. Thus, these agents may be exposed to a total flooding system that introduces the agent into a closed area (eg, a room or other enclosure) surrounding the flame at a concentration sufficient for fire suppression.
fire extinguishing system).
Here, the total flooding system means that the entire area surrounding the fire (for example, the entire room) is filled with a fire extinguishing agent (fl
ooded) means the system. The term is a system distinguished from directing a flow of fire extinguisher directly into a fire, such as putting fire extinguisher into the fire with a digestive organ. According to the total flooding system, even in equipment, equipment or rooms or enclosures,
A fire extinguisher supply, suitable piping, valves and controls may be provided so that the fire extinguishing agent can be introduced automatically or manually at the appropriate concentration in the event of a fire. In this way, the fire extinguisher can be compressed with nitrogen or other inert gas to about 600 psi at ambient conditions, as is well known to those skilled in the art.

Alternatively, the hydrofluorocarbon agent can be supplied to the fire using conventional portable fire fighting equipment. In order to completely release the agent from the fire extinguisher, it is common practice to increase the pressure in the portable fire extinguisher with nitrogen or other inert gas. The hydrofluorocarbon-containing system according to the present invention can be conveniently compressed at ambient conditions at preferred pressures up to about 600 psi.

The practice of the present invention is illustrated by the following examples, which are intended to be illustrative, not limiting.

Example 1 A 28.3 cubic litre test enclosure was configured for a static extinction test (total flooding). Plexiglass viewing window (viewpoint)
And a test agent inlet at the top and an air inlet near the bottom. To test the agent, a 90 × 50 mm glass dish was placed in the center of the enclosure and filled with 10 g of cigarette lighter fluid available under the trademark RONSONOL. The fuel was ignited and pre-burned for 15 seconds before introducing the agent. During pre-combustion, air was introduced into the enclosure through the lower inlet. After 15 seconds, the air inlet was closed and the fire extinguisher was placed in the enclosure. Sufficient to form a concentration of 6.6% v / v of the active agent,
A predetermined amount of the agent was supplied. The extingushment time was measured as the time between the agent injection time and the extinction. Table 1 shows the average fire extinguishing time of heptafluoropropane, halon 1301, halon 1211 and CF ₃ CHFBr at a 6.6% (v / v) concentration.

Example 2 The experimental method of Example 1 was carried out using heptane as fuel. The average fire extinguishing time for the same agent at 6.6% v / v is shown in Table 1.

This table shows the extinguishing time required for various fuels at 6.6% v / v of the active agent used. At this level, heptafluoropropane is as effective as bromine-containing halon in extinguishing n-heptane flames and almost as effective in extinguishing lighter fluid flames as other extinguishing agents.

For general use of the pure hydrofluorocarbons according to the invention, levels of about 5-10% are preferred. The use of too little agent results in fire extinguishing failures, resulting in excessive smoke and possibly HF emissions due to agent burning. The use of excess amounts is uneconomical and can result in dilution of the oxygen level of the air to levels harmful to the organism.

Example 3 Two white mice were placed in a chamber and Example 1
Was repeated. After extinguishing, the mice were exposed to the combustion products for a total of 10 minutes before removal from the pen. All mice showed no pathological effects during exposure and appeared to behave normally after removal from the device.

Example 4 A flame generated in a glass cup burner with air and n-
Dynamic burn test data was obtained for heptafluoropropane and 1,1,1,2,3,3-hexafluoropropane using a cup burner test method that continuously supplies butane. The vapor of the test agent was mixed with air and introduced into the flame, and the concentration of the agent was gradually increased until the flow was just enough to cause quenching. In this way, data for heptafluoropropane and 1,1,1,2,3,3-hexafluoropropane were obtained and, for comparison, the following other halon agents: Halon 1301 (CF ₃ Br), Ha Long 1
211 (CF ₂ BrCl), Halon 251 (CF ₃ CF ₂ Cl), Halon 25 (C
Data on F ₃ CF ₂ H) and Halon 14 (CF ₄ ) were obtained.
Table 2 shows the concentration of each agent in the air required for quenching.

Heptafluoropropane and Halon 1301, Halon 1211,
The n-heptane diffusion flame was extinguished by the method of Example 4 using Halon 251. The test data is reported in Table 3.

Table 2 dynamic test data reported in 3 heptafluoropropane according to the present invention, 1,1,1,2,3,3 use of hexafluoropropane and pentafluoroethane, e.g. Halon 14 (CF ₄₎ Demonstrate that it is significantly more effective than other known bromine or chlorine free halons, such as In addition, heptafluoropropane, in effect, is a chlorine-containing chlorofluorocarbon, Halon 251
Is comparable to The latter relationship is between n-heptane fuel and n-heptane.
Shown for butane fuel. Bromine and chlorine containing agents such as Halon 1301 and Halon 1211 are somewhat more effective than hydrofluorocarbon agents under the cup burner test, but the use of agents according to the present invention is still very effective. , These uses are for example Halon 13
Significant environmental handicaps such as those found with chlorine and bromine containing halons, such as 01, halon 1211, halon 251 can be avoided.

Example 6 Using the method of Example 1, 1,1,1,
Static box flame extinguishment test for 3,3,3-hexafluoropropane
I got In addition to 1,1,1,3,3,3-hexafluoropropane, Halon 1301, Halon 1211 and Halon 25 for comparison.
One was also tested. All agents were supplied at 5.5% (v / v) test conditions.

Table 4 Extinguishing time of 5.5% (v / v) agent (seconds) Agent extinguishing time (seconds) Halon 1301 1.02 (CF ₃ Br) Halon 1211 1.76 (CF ₂ BrCl) Halon 251 2.15 (CF ₃ CF ₂ Cl) CF ₃ CH ₂ CF ₃ 2.98 The data in Table 4 demonstrates that 1,1,1,3,3,3-hexafluoropropane is a very effective fire extinguishing agent. It is almost as effective as Halon 251, chlorofluorocarbons and is sufficiently effective when compared to bromine containing halons, such as Halon 1301 and Halon 1211, and ozone depletion of chlorine and bromine containing halon. (Ozone de
pletion) is preferred because there are no other environmental effects.

1,1,1,2,3,3-Hexafluoropropane, at the concentration according to the method of the invention, besides being a very effective fire extinguishing agent, is well within the toxicologically safe range.

The following example demonstrates the effective use of a hydrofluorocarbon agent according to the present invention as a mixture or blend containing a bromine-containing halon fire extinguisher.

Example 7 Dynamic test data using the cup burner method of Example 4 was obtained for various mixtures of heptafluoropropane and Halon 1201 (CF ₂ HBr). The air and agent mixture were continuously fed to an n-heptane diffusion flame created in a glass cup burner. For a constant heptafluoropropane flow, the CF ₂ HBr flow was gradually increased until the flow was just enough to cause quenching. The experiment was repeated at various heptafluoropropane flow rates and the results are reported in Table 6.

Table 6 reports the actual volume percentage of air observed. Table 6 also reports the calculated weight percent of heptafluoropropane in the mixture. In addition, Table 6 reports the ozone depletion potential (ODP) of each agent.
ODP data of Halon 1201 was calculated as follows. The ODP of the pure compound was calculated by the following formula: ODP = AEP [(# C1) ^B + C (#Br)] D ^{(# C-11) In} this expression, P is the photolysis facto
r). If there are no special structural features that cause tropospheric photolysis of the molecule, then P = 1.0. Otherwise, P = F, G, or H, as shown in the table of constants (Table 5 below).

The ODP of the mixture was obtained by multiplying the weight percent of Halon 1201 by the ODP of pure Halon 1201.

These data are for heptafluoropropane and halon
That effective extinction is carried out by the mixture with 1201;
And that the ODP of Halon 1201 is significantly reduced by supplying heptafluoropropane therewith.

Examples 8 to 11 Tables 7, 8, 9 and 10 show examples 7 for the following agent mixtures:
Report the diffusion quenching data obtained using the method of Table 7: Heptafluoropropane and Halon 1211 (CF ₂ BrC
l) Table 8 heptafluoropropane and Halon 1301 (CF ₃ Br) Table 9 pentafluoropropane and Halon 1201 (CF ₂ HBr) Table 10-1,1,1,2,3,3- hexafluoropropane and Halon 1
201 (CF ₂ HBr) These tables are from Lawrence Rivermore Research
Laboratory (Lawrence Livermore Research Laborato)
ries) reported by pure Halon 1211 and 1301
Also includes ODP data. The ODP data for Halon 1201 was obtained using the method described above, and the ODP data for the mixture was obtained by multiplying the weight percent of Halon agonist by the ODP of pure Halon.

The data in Tables 7-10 show that various mixtures of hydrofluorocarbons and chlorine and / or bromine containing halons according to the present invention are useful fire extinguishing agents, and that a significant reduction in the ODP of chlorine and / or bromine containing materials. It demonstrates that this is achieved by mixing the hydrofluorocarbon according to the invention with it. As well as the chlorine and / or bromine-containing halon used according to the invention, for example heptafluoropropane, 1,1,1,2,3,3-hexafluoropropane,
1,1,1,3,3,3 saturated high fluorinated C ₂ and C ₃ hydrofluorocarbons such as hexafluoropropane and pentafluoroethane is a non-destructive agents, other media (me
This is particularly useful when dia) cleanup is problematic. Some of the uses of the present invention are to extinguish liquid and gas burning fires; protection of electrical equipment such as ordinary combustibles such as wood, paper and textiles, hazardous solids; and computer equipment, data processing equipment and control rooms. Protection.

 ──────────────────────────────────────────────────続 き Continuing the front page (72) Inventor Robin, Mark Leicester, 47906, West Lafayette, Indiana, United States 5411 Hillside Lane 5411 (56) References US Pat. 4459213 (US, A)

Claims (12)

(57) [Claims] A compound of the formula: C _x H _y F _{z wherein} x is 2 or 3, y is 1 or 2, z is 5, 6 or 7; Is that y is 1 and z is 5; x is 3
Where z is 6 or 7]
A composition consisting essentially of only one or more compounds is introduced into the air surrounding the fire in an amount such that the fire extinguishing concentration in the air is sufficient to extinguish the fire to be extinguished. A method of extinguishing fire that comprises introducing and maintaining this concentration of the composition until the fire is extinguished. 2. The method of claim 1 wherein the compound is used at a level of less than about 15% (v / v). 3. The method of claim 1 wherein the fire fighting concentration of the compound is about 5-10% (v / v). 4. The method of claim 1 wherein the compound is used in a total flooding system. 5. A compound of the formula: C _x H _y F _{z wherein} x is 2 or 3, y is 1 or 2, z is 5, 6 or 7; Is that y is 1 and z is 5; x is 3
Where z is 6 or 7]
Use of a composition consisting essentially of only one or more compounds as a non-ozone depleting fire extinguisher. 6. The compound according to claim 1, wherein the compound is heptafluoropropane, 1,1,1,
The method according to claim 1, wherein the element is selected from the group consisting of 3,3,3-hexafluoropropane, 1,1,1,2,3,3-hexafluoropropane, pentafluoroethane, and mixtures thereof. 7. The method according to claim 1, wherein the compound is heptafluoropropane. 8. The step of introducing a composition consisting essentially of heptafluoropropane into the fire at a concentration of about 5 to 15% (v / v) and maintaining this concentration of heptafluoropropane until the fire is extinguished. Extinguishing a fire extinguishing method. 9. The formula: C _x H _y F _{z wherein} x is 2 or 3, y is 1 or 2, z is 5, 6 or 7; Is that y is 1 and z is 5; x is 3
Where z is 6 or 7]
Substantially composition consisting only or more _{compounds, CF 3 Br, CF 2 BrCl} , CF 3 CF 2 Cl, CF 2 BrCF 2 Br, CF 2 HBr , and CF
_{3 A} mixture comprising one or more chlorine and / or bromine-containing fire extinguishers selected from the group consisting of CHFBr, wherein the composition is present in the mixture at a level of at least about 10% by weight of the mixture. Introducing into the air surrounding the fire an amount of the mixture that is sufficient to extinguish the fire to be extinguished, such that the concentration of the mixture is sufficient to extinguish the fire; and maintaining this concentration of the mixture until the fire is extinguished. Fire extinguishing methods including. 10. The fire-extinguishing concentration of the mixture is about 3 to 15% (v / v).
The method of claim 9, wherein 11. The following elements: Formula C _x H _y F _{z wherein} x is 2 or 3, y is 1 or 2, z is 5, 6 or 7; x is 2 In some cases, y is 1 and z is 5; when x is 3, z
Is 6 or 7] comprising at least about 10% by weight of the mixture substantially consisting of only one or more compounds represented by the formula: CF ₃ Br, CF ₂ BrCl, CF ₃ CF ₂ Cl , CF ₂ BrCF ₂ Br, CF ₂ HBr and CF
₃ A fire extinguishing mixture comprising up to about 90% by weight of the mixture of one or more chlorine and / or bromine containing fire extinguishing agents selected from the group consisting of CHFBr. 12. The fire extinguishing mixture according to claim 11, wherein the compound is heptafluoropropane and the element is CF ₂ HBr.